Signed-off-by: Huacai Chen <[email protected]>
---
arch/loongarch/Kconfig | 2 +
arch/loongarch/include/uapi/asm/perf_regs.h | 40 +
arch/loongarch/kernel/Makefile | 2 +
arch/loongarch/kernel/perf_event.c | 909 ++++++++++++++++++++
arch/loongarch/kernel/perf_regs.c | 50 ++
5 files changed, 1003 insertions(+)
create mode 100644 arch/loongarch/include/uapi/asm/perf_regs.h
create mode 100644 arch/loongarch/kernel/perf_event.c
create mode 100644 arch/loongarch/kernel/perf_regs.c
diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
index 24665808cf3d..9478f9646fa5 100644
--- a/arch/loongarch/Kconfig
+++ b/arch/loongarch/Kconfig
@@ -93,6 +93,8 @@ config LOONGARCH
select HAVE_NMI
select HAVE_PCI
select HAVE_PERF_EVENTS
+ select HAVE_PERF_REGS
+ select HAVE_PERF_USER_STACK_DUMP
select HAVE_REGS_AND_STACK_ACCESS_API
select HAVE_RSEQ
select HAVE_SETUP_PER_CPU_AREA if NUMA
diff --git a/arch/loongarch/include/uapi/asm/perf_regs.h b/arch/loongarch/include/uapi/asm/perf_regs.h
new file mode 100644
index 000000000000..9943d418e01d
--- /dev/null
+++ b/arch/loongarch/include/uapi/asm/perf_regs.h
@@ -0,0 +1,40 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+#ifndef _ASM_LOONGARCH_PERF_REGS_H
+#define _ASM_LOONGARCH_PERF_REGS_H
+
+enum perf_event_loongarch_regs {
+ PERF_REG_LOONGARCH_PC,
+ PERF_REG_LOONGARCH_R1,
+ PERF_REG_LOONGARCH_R2,
+ PERF_REG_LOONGARCH_R3,
+ PERF_REG_LOONGARCH_R4,
+ PERF_REG_LOONGARCH_R5,
+ PERF_REG_LOONGARCH_R6,
+ PERF_REG_LOONGARCH_R7,
+ PERF_REG_LOONGARCH_R8,
+ PERF_REG_LOONGARCH_R9,
+ PERF_REG_LOONGARCH_R10,
+ PERF_REG_LOONGARCH_R11,
+ PERF_REG_LOONGARCH_R12,
+ PERF_REG_LOONGARCH_R13,
+ PERF_REG_LOONGARCH_R14,
+ PERF_REG_LOONGARCH_R15,
+ PERF_REG_LOONGARCH_R16,
+ PERF_REG_LOONGARCH_R17,
+ PERF_REG_LOONGARCH_R18,
+ PERF_REG_LOONGARCH_R19,
+ PERF_REG_LOONGARCH_R20,
+ PERF_REG_LOONGARCH_R21,
+ PERF_REG_LOONGARCH_R22,
+ PERF_REG_LOONGARCH_R23,
+ PERF_REG_LOONGARCH_R24,
+ PERF_REG_LOONGARCH_R25,
+ PERF_REG_LOONGARCH_R26,
+ PERF_REG_LOONGARCH_R27,
+ PERF_REG_LOONGARCH_R28,
+ PERF_REG_LOONGARCH_R29,
+ PERF_REG_LOONGARCH_R30,
+ PERF_REG_LOONGARCH_R31,
+ PERF_REG_LOONGARCH_MAX = PERF_REG_LOONGARCH_R31 + 1,
+};
+#endif /* _ASM_LOONGARCH_PERF_REGS_H */
diff --git a/arch/loongarch/kernel/Makefile b/arch/loongarch/kernel/Makefile
index e5be17009fe8..a213e994db68 100644
--- a/arch/loongarch/kernel/Makefile
+++ b/arch/loongarch/kernel/Makefile
@@ -26,4 +26,6 @@ obj-$(CONFIG_NUMA) += numa.o
obj-$(CONFIG_UNWINDER_GUESS) += unwind_guess.o
obj-$(CONFIG_UNWINDER_PROLOGUE) += unwind_prologue.o
+obj-$(CONFIG_PERF_EVENTS) += perf_event.o perf_regs.o
+
CPPFLAGS_vmlinux.lds := $(KBUILD_CFLAGS)
diff --git a/arch/loongarch/kernel/perf_event.c b/arch/loongarch/kernel/perf_event.c
new file mode 100644
index 000000000000..00cdbcebaf80
--- /dev/null
+++ b/arch/loongarch/kernel/perf_event.c
@@ -0,0 +1,909 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Linux performance counter support for LoongArch.
+ *
+ * Copyright (C) 2022 Loongson Technology Corporation Limited
+ */
+
+#include <linux/cpumask.h>
+#include <linux/interrupt.h>
+#include <linux/smp.h>
+#include <linux/kernel.h>
+#include <linux/perf_event.h>
+#include <linux/uaccess.h>
+#include <linux/sched/task_stack.h>
+
+#include <asm/irq.h>
+#include <asm/irq_regs.h>
+#include <asm/stacktrace.h>
+#include <asm/unwind.h>
+
+/*
+ * Get the return address for a single stackframe and return a pointer to the
+ * next frame tail.
+ */
+static unsigned long
+user_backtrace(struct perf_callchain_entry_ctx *entry, unsigned long fp)
+{
+ struct stack_frame buftail;
+ unsigned long err;
+ unsigned long __user *user_frame_tail = (unsigned long *)(fp - sizeof(struct stack_frame));
+
+ /* Also check accessibility of one struct frame_tail beyond */
+ if (!access_ok(user_frame_tail, sizeof(buftail)))
+ return 0;
+
+ pagefault_disable();
+ err = __copy_from_user_inatomic(&buftail, user_frame_tail, sizeof(buftail));
+ pagefault_enable();
+
+ if (err || (unsigned long)user_frame_tail >= buftail.fp)
+ return 0;
+
+ perf_callchain_store(entry, buftail.ra);
+
+ return buftail.fp;
+}
+
+void perf_callchain_user(struct perf_callchain_entry_ctx *entry,
+ struct pt_regs *regs)
+{
+ unsigned long fp;
+
+ if (perf_guest_state()) {
+ /* We don't support guest os callchain now */
+ return;
+ }
+
+ perf_callchain_store(entry, regs->csr_era);
+
+ fp = regs->regs[22];
+
+ while (entry->nr < entry->max_stack && fp && !((unsigned long)fp & 0xf))
+ fp = user_backtrace(entry, fp);
+}
+
+void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry,
+ struct pt_regs *regs)
+{
+ struct unwind_state state;
+ unsigned long addr;
+
+ for (unwind_start(&state, current, regs);
+ !unwind_done(&state); unwind_next_frame(&state)) {
+ addr = unwind_get_return_address(&state);
+ if (!addr || perf_callchain_store(entry, addr))
+ return;
+ }
+}
+
+#define LOONGARCH_MAX_HWEVENTS 4
+
+struct cpu_hw_events {
+ /* Array of events on this cpu. */
+ struct perf_event *events[LOONGARCH_MAX_HWEVENTS];
+
+ /*
+ * Set the bit (indexed by the counter number) when the counter
+ * is used for an event.
+ */
+ unsigned long used_mask[BITS_TO_LONGS(LOONGARCH_MAX_HWEVENTS)];
+
+ /*
+ * Software copy of the control register for each performance counter.
+ * LoongArch CPUs vary in performance counters. They use this differently,
+ * and even may not use it.
+ */
+ unsigned int saved_ctrl[LOONGARCH_MAX_HWEVENTS];
+};
+static DEFINE_PER_CPU(struct cpu_hw_events, cpu_hw_events) = {
+ .saved_ctrl = {0},
+};
+
+/* The description of LoongArch performance events. */
+struct loongarch_perf_event {
+ unsigned int event_id;
+};
+
+static struct loongarch_perf_event raw_event;
+static DEFINE_MUTEX(raw_event_mutex);
+
+#define C(x) PERF_COUNT_HW_CACHE_##x
+#define HW_OP_UNSUPPORTED 0xffffffff
+#define CACHE_OP_UNSUPPORTED 0xffffffff
+
+#define PERF_MAP_ALL_UNSUPPORTED \
+ [0 ... PERF_COUNT_HW_MAX - 1] = {HW_OP_UNSUPPORTED}
+
+#define PERF_CACHE_MAP_ALL_UNSUPPORTED \
+[0 ... C(MAX) - 1] = { \
+ [0 ... C(OP_MAX) - 1] = { \
+ [0 ... C(RESULT_MAX) - 1] = {CACHE_OP_UNSUPPORTED}, \
+ }, \
+}
+
+struct loongarch_pmu {
+ u64 max_period;
+ u64 valid_count;
+ u64 overflow;
+ const char *name;
+ u64 (*read_counter)(unsigned int idx);
+ void (*write_counter)(unsigned int idx, u64 val);
+ const struct loongarch_perf_event *(*map_raw_event)(u64 config);
+ const struct loongarch_perf_event (*general_event_map)[PERF_COUNT_HW_MAX];
+ const struct loongarch_perf_event (*cache_event_map)
+ [PERF_COUNT_HW_CACHE_MAX]
+ [PERF_COUNT_HW_CACHE_OP_MAX]
+ [PERF_COUNT_HW_CACHE_RESULT_MAX];
+ unsigned int num_counters;
+};
+
+static struct loongarch_pmu loongarch_pmu;
+
+#define M_PERFCTL_EVENT(event) (event & CSR_PERFCTRL_EVENT)
+
+#define M_PERFCTL_COUNT_EVENT_WHENEVER (CSR_PERFCTRL_PLV0 | \
+ CSR_PERFCTRL_PLV1 | \
+ CSR_PERFCTRL_PLV2 | \
+ CSR_PERFCTRL_PLV3 | \
+ CSR_PERFCTRL_IE)
+
+#define M_PERFCTL_CONFIG_MASK 0x1f0000
+
+#define CNTR_BIT_MASK(n) (((n) == 64) ? ~0ULL : ((1ULL<<(n))-1))
+
+static void resume_local_counters(void);
+static void pause_local_counters(void);
+
+static u64 loongarch_pmu_read_counter(unsigned int idx)
+{
+ u64 val = -1;
+
+ switch (idx) {
+ case 0:
+ val = read_csr_perfcntr0();
+ break;
+ case 1:
+ val = read_csr_perfcntr1();
+ break;
+ case 2:
+ val = read_csr_perfcntr2();
+ break;
+ case 3:
+ val = read_csr_perfcntr3();
+ break;
+ default:
+ WARN_ONCE(1, "Invalid performance counter number (%d)\n", idx);
+ return 0;
+ }
+
+ return val;
+}
+
+static void loongarch_pmu_write_counter(unsigned int idx, u64 val)
+{
+ switch (idx) {
+ case 0:
+ write_csr_perfcntr0(val);
+ return;
+ case 1:
+ write_csr_perfcntr1(val);
+ return;
+ case 2:
+ write_csr_perfcntr2(val);
+ return;
+ case 3:
+ write_csr_perfcntr3(val);
+ return;
+ }
+}
+
+static unsigned int loongarch_pmu_read_control(unsigned int idx)
+{
+ unsigned int val = -1;
+
+ switch (idx) {
+ case 0:
+ val = read_csr_perfctrl0();
+ break;
+ case 1:
+ val = read_csr_perfctrl1();
+ break;
+ case 2:
+ val = read_csr_perfctrl2();
+ break;
+ case 3:
+ val = read_csr_perfctrl3();
+ break;
+ default:
+ WARN_ONCE(1, "Invalid performance counter number (%d)\n", idx);
+ return 0;
+ }
+
+ return val;
+}
+
+static void loongarch_pmu_write_control(unsigned int idx, unsigned int val)
+{
+ switch (idx) {
+ case 0:
+ write_csr_perfctrl0(val);
+ return;
+ case 1:
+ write_csr_perfctrl1(val);
+ return;
+ case 2:
+ write_csr_perfctrl2(val);
+ return;
+ case 3:
+ write_csr_perfctrl3(val);
+ return;
+ }
+}
+
+static int loongarch_pmu_alloc_counter(struct cpu_hw_events *cpuc,
+ struct hw_perf_event *hwc)
+{
+ int i;
+
+ for (i = loongarch_pmu.num_counters - 1; i >= 0; i--) {
+ if (!test_and_set_bit(i, cpuc->used_mask))
+ return i;
+ }
+
+ return -EAGAIN;
+}
+
+static void loongarch_pmu_enable_event(struct hw_perf_event *evt, int idx)
+{
+ struct perf_event *event = container_of(evt, struct perf_event, hw);
+ struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
+ unsigned int cpu;
+
+ WARN_ON(idx < 0 || idx >= loongarch_pmu.num_counters);
+
+ cpuc->saved_ctrl[idx] = M_PERFCTL_EVENT(evt->event_base & 0xff) |
+ (evt->config_base & M_PERFCTL_CONFIG_MASK) |
+ /* Make sure interrupt enabled. */
+ CSR_PERFCTRL_IE;
+
+ cpu = (event->cpu >= 0) ? event->cpu : smp_processor_id();
+
+ pr_debug("Enabling perf counter for CPU%d\n", cpu);
+ /*
+ * We do not actually let the counter run. Leave it until start().
+ */
+}
+
+static void loongarch_pmu_disable_event(int idx)
+{
+ struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
+ unsigned long flags;
+
+ WARN_ON(idx < 0 || idx >= loongarch_pmu.num_counters);
+
+ local_irq_save(flags);
+ cpuc->saved_ctrl[idx] = loongarch_pmu_read_control(idx) &
+ ~M_PERFCTL_COUNT_EVENT_WHENEVER;
+ loongarch_pmu_write_control(idx, cpuc->saved_ctrl[idx]);
+ local_irq_restore(flags);
+}
+
+static int loongarch_pmu_event_set_period(struct perf_event *event,
+ struct hw_perf_event *hwc,
+ int idx)
+{
+ u64 left = local64_read(&hwc->period_left);
+ u64 period = hwc->sample_period;
+ int ret = 0;
+
+ if (unlikely((left + period) & (1ULL << 63))) {
+ /* left underflowed by more than period. */
+ left = period;
+ local64_set(&hwc->period_left, left);
+ hwc->last_period = period;
+ ret = 1;
+ } else if (unlikely((left + period) <= period)) {
+ /* left underflowed by less than period. */
+ left += period;
+ local64_set(&hwc->period_left, left);
+ hwc->last_period = period;
+ ret = 1;
+ }
+
+ if (left > loongarch_pmu.max_period) {
+ left = loongarch_pmu.max_period;
+ local64_set(&hwc->period_left, left);
+ }
+
+ local64_set(&hwc->prev_count, loongarch_pmu.overflow - left);
+
+ loongarch_pmu.write_counter(idx, loongarch_pmu.overflow - left);
+
+ perf_event_update_userpage(event);
+
+ return ret;
+}
+
+static void loongarch_pmu_event_update(struct perf_event *event,
+ struct hw_perf_event *hwc,
+ int idx)
+{
+ u64 delta;
+ u64 prev_raw_count, new_raw_count;
+
+again:
+ prev_raw_count = local64_read(&hwc->prev_count);
+ new_raw_count = loongarch_pmu.read_counter(idx);
+
+ if (local64_cmpxchg(&hwc->prev_count, prev_raw_count,
+ new_raw_count) != prev_raw_count)
+ goto again;
+
+ delta = new_raw_count - prev_raw_count;
+
+ local64_add(delta, &event->count);
+ local64_sub(delta, &hwc->period_left);
+}
+
+static void loongarch_pmu_start(struct perf_event *event, int flags)
+{
+ struct hw_perf_event *hwc = &event->hw;
+
+ if (flags & PERF_EF_RELOAD)
+ WARN_ON_ONCE(!(hwc->state & PERF_HES_UPTODATE));
+
+ hwc->state = 0;
+
+ /* Set the period for the event. */
+ loongarch_pmu_event_set_period(event, hwc, hwc->idx);
+
+ /* Enable the event. */
+ loongarch_pmu_enable_event(hwc, hwc->idx);
+}
+
+static void loongarch_pmu_stop(struct perf_event *event, int flags)
+{
+ struct hw_perf_event *hwc = &event->hw;
+
+ if (!(hwc->state & PERF_HES_STOPPED)) {
+ /* We are working on a local event. */
+ loongarch_pmu_disable_event(hwc->idx);
+ barrier();
+ loongarch_pmu_event_update(event, hwc, hwc->idx);
+ hwc->state |= PERF_HES_STOPPED | PERF_HES_UPTODATE;
+ }
+}
+
+static int loongarch_pmu_add(struct perf_event *event, int flags)
+{
+ struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
+ struct hw_perf_event *hwc = &event->hw;
+ int idx;
+ int err = 0;
+
+ perf_pmu_disable(event->pmu);
+
+ /* To look for a free counter for this event. */
+ idx = loongarch_pmu_alloc_counter(cpuc, hwc);
+ if (idx < 0) {
+ err = idx;
+ goto out;
+ }
+
+ /*
+ * If there is an event in the counter we are going to use then
+ * make sure it is disabled.
+ */
+ event->hw.idx = idx;
+ loongarch_pmu_disable_event(idx);
+ cpuc->events[idx] = event;
+
+ hwc->state = PERF_HES_STOPPED | PERF_HES_UPTODATE;
+ if (flags & PERF_EF_START)
+ loongarch_pmu_start(event, PERF_EF_RELOAD);
+
+ /* Propagate our changes to the userspace mapping. */
+ perf_event_update_userpage(event);
+
+out:
+ perf_pmu_enable(event->pmu);
+ return err;
+}
+
+static void loongarch_pmu_del(struct perf_event *event, int flags)
+{
+ struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
+ struct hw_perf_event *hwc = &event->hw;
+ int idx = hwc->idx;
+
+ WARN_ON(idx < 0 || idx >= loongarch_pmu.num_counters);
+
+ loongarch_pmu_stop(event, PERF_EF_UPDATE);
+ cpuc->events[idx] = NULL;
+ clear_bit(idx, cpuc->used_mask);
+
+ perf_event_update_userpage(event);
+}
+
+static void loongarch_pmu_read(struct perf_event *event)
+{
+ struct hw_perf_event *hwc = &event->hw;
+
+ /* Don't read disabled counters! */
+ if (hwc->idx < 0)
+ return;
+
+ loongarch_pmu_event_update(event, hwc, hwc->idx);
+}
+
+static void loongarch_pmu_enable(struct pmu *pmu)
+{
+ resume_local_counters();
+}
+
+static void loongarch_pmu_disable(struct pmu *pmu)
+{
+ pause_local_counters();
+}
+
+static atomic_t active_events = ATOMIC_INIT(0);
+static DEFINE_MUTEX(pmu_reserve_mutex);
+
+static void reset_counters(void *arg);
+static int __hw_perf_event_init(struct perf_event *event);
+
+static void hw_perf_event_destroy(struct perf_event *event)
+{
+ if (atomic_dec_and_mutex_lock(&active_events,
+ &pmu_reserve_mutex)) {
+ /*
+ * We must not call the destroy function with interrupts
+ * disabled.
+ */
+ on_each_cpu(reset_counters,
+ (void *)(long)loongarch_pmu.num_counters, 1);
+ mutex_unlock(&pmu_reserve_mutex);
+ }
+}
+
+/* This is needed by specific irq handlers in perf_event_*.c */
+static void handle_associated_event(struct cpu_hw_events *cpuc,
+ int idx, struct perf_sample_data *data,
+ struct pt_regs *regs)
+{
+ struct perf_event *event = cpuc->events[idx];
+ struct hw_perf_event *hwc = &event->hw;
+
+ loongarch_pmu_event_update(event, hwc, idx);
+ data->period = event->hw.last_period;
+ if (!loongarch_pmu_event_set_period(event, hwc, idx))
+ return;
+
+ if (perf_event_overflow(event, data, regs))
+ loongarch_pmu_disable_event(idx);
+}
+
+static irqreturn_t pmu_handle_irq(int irq, void *dev)
+{
+ int handled = IRQ_NONE;
+ unsigned int counters = loongarch_pmu.num_counters;
+ u64 counter;
+ struct pt_regs *regs;
+ struct perf_sample_data data;
+ struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
+
+ /*
+ * First we pause the local counters, so that when we are locked
+ * here, the counters are all paused. When it gets locked due to
+ * perf_disable(), the timer interrupt handler will be delayed.
+ *
+ * See also loongarch_pmu_start().
+ */
+ pause_local_counters();
+
+ regs = get_irq_regs();
+
+ perf_sample_data_init(&data, 0, 0);
+
+ switch (counters) {
+#define HANDLE_COUNTER(n) \
+ case n + 1: \
+ if (test_bit(n, cpuc->used_mask)) { \
+ counter = loongarch_pmu.read_counter(n); \
+ if (counter & loongarch_pmu.overflow) { \
+ handle_associated_event(cpuc, n, &data, regs); \
+ handled = IRQ_HANDLED; \
+ } \
+ }
+ HANDLE_COUNTER(3)
+ fallthrough;
+ HANDLE_COUNTER(2)
+ fallthrough;
+ HANDLE_COUNTER(1)
+ fallthrough;
+ HANDLE_COUNTER(0)
+ }
+
+ resume_local_counters();
+
+ /*
+ * Do all the work for the pending perf events. We can do this
+ * in here because the performance counter interrupt is a regular
+ * interrupt, not NMI.
+ */
+ if (handled == IRQ_HANDLED)
+ irq_work_run();
+
+ return handled;
+}
+
+static int get_pmc_irq(void)
+{
+ struct irq_domain *d = irq_find_matching_fwnode(cpuintc_handle, DOMAIN_BUS_ANY);
+
+ if (d)
+ return irq_create_mapping(d, EXCCODE_PMC - EXCCODE_INT_START);
+
+ return -EINVAL;
+}
+
+static int loongarch_pmu_event_init(struct perf_event *event)
+{
+ int r, irq;
+ unsigned long flags;
+
+ /* does not support taken branch sampling */
+ if (has_branch_stack(event))
+ return -EOPNOTSUPP;
+
+ switch (event->attr.type) {
+ case PERF_TYPE_RAW:
+ case PERF_TYPE_HARDWARE:
+ case PERF_TYPE_HW_CACHE:
+ break;
+
+ default:
+ /* Init it to avoid false validate_group */
+ event->hw.event_base = 0xffffffff;
+ return -ENOENT;
+ }
+
+ if (event->cpu >= 0 && !cpu_online(event->cpu))
+ return -ENODEV;
+
+ irq = get_pmc_irq();
+ flags = IRQF_PERCPU | IRQF_NOBALANCING | IRQF_NO_THREAD | IRQF_NO_SUSPEND | IRQF_SHARED;
+ if (!atomic_inc_not_zero(&active_events)) {
+ mutex_lock(&pmu_reserve_mutex);
+ if (atomic_read(&active_events) == 0) {
+ r = request_irq(irq, pmu_handle_irq,
+ flags, "Perf_PMU", &loongarch_pmu);
+ if (r < 0) {
+ pr_warn("PMU IRQ request failed\n");
+ return -ENODEV;
+ }
+ }
+ atomic_inc(&active_events);
+ mutex_unlock(&pmu_reserve_mutex);
+ }
+
+ return __hw_perf_event_init(event);
+}
+
+static struct pmu pmu = {
+ .pmu_enable = loongarch_pmu_enable,
+ .pmu_disable = loongarch_pmu_disable,
+ .event_init = loongarch_pmu_event_init,
+ .add = loongarch_pmu_add,
+ .del = loongarch_pmu_del,
+ .start = loongarch_pmu_start,
+ .stop = loongarch_pmu_stop,
+ .read = loongarch_pmu_read,
+};
+
+static unsigned int loongarch_pmu_perf_event_encode(const struct loongarch_perf_event *pev)
+{
+ return (pev->event_id & 0xff);
+}
+
+static const struct loongarch_perf_event *loongarch_pmu_map_general_event(int idx)
+{
+ const struct loongarch_perf_event *pev;
+
+ pev = &(*loongarch_pmu.general_event_map)[idx];
+
+ if (pev->event_id == HW_OP_UNSUPPORTED)
+ return ERR_PTR(-ENOENT);
+
+ return pev;
+}
+
+static const struct loongarch_perf_event *loongarch_pmu_map_cache_event(u64 config)
+{
+ unsigned int cache_type, cache_op, cache_result;
+ const struct loongarch_perf_event *pev;
+
+ cache_type = (config >> 0) & 0xff;
+ if (cache_type >= PERF_COUNT_HW_CACHE_MAX)
+ return ERR_PTR(-EINVAL);
+
+ cache_op = (config >> 8) & 0xff;
+ if (cache_op >= PERF_COUNT_HW_CACHE_OP_MAX)
+ return ERR_PTR(-EINVAL);
+
+ cache_result = (config >> 16) & 0xff;
+ if (cache_result >= PERF_COUNT_HW_CACHE_RESULT_MAX)
+ return ERR_PTR(-EINVAL);
+
+ pev = &((*loongarch_pmu.cache_event_map)
+ [cache_type]
+ [cache_op]
+ [cache_result]);
+
+ if (pev->event_id == CACHE_OP_UNSUPPORTED)
+ return ERR_PTR(-ENOENT);
+
+ return pev;
+}
+
+static int validate_group(struct perf_event *event)
+{
+ struct perf_event *sibling, *leader = event->group_leader;
+ struct cpu_hw_events fake_cpuc;
+
+ memset(&fake_cpuc, 0, sizeof(fake_cpuc));
+
+ if (loongarch_pmu_alloc_counter(&fake_cpuc, &leader->hw) < 0)
+ return -EINVAL;
+
+ for_each_sibling_event(sibling, leader) {
+ if (loongarch_pmu_alloc_counter(&fake_cpuc, &sibling->hw) < 0)
+ return -EINVAL;
+ }
+
+ if (loongarch_pmu_alloc_counter(&fake_cpuc, &event->hw) < 0)
+ return -EINVAL;
+
+ return 0;
+}
+
+static void reset_counters(void *arg)
+{
+ int counters = (int)(long)arg;
+
+ switch (counters) {
+ case 4:
+ loongarch_pmu_write_control(3, 0);
+ loongarch_pmu.write_counter(3, 0);
+ fallthrough;
+ case 3:
+ loongarch_pmu_write_control(2, 0);
+ loongarch_pmu.write_counter(2, 0);
+ fallthrough;
+ case 2:
+ loongarch_pmu_write_control(1, 0);
+ loongarch_pmu.write_counter(1, 0);
+ fallthrough;
+ case 1:
+ loongarch_pmu_write_control(0, 0);
+ loongarch_pmu.write_counter(0, 0);
+ }
+}
+
+static const struct loongarch_perf_event loongson_new_event_map[PERF_COUNT_HW_MAX] = {
+ PERF_MAP_ALL_UNSUPPORTED,
+ [PERF_COUNT_HW_CPU_CYCLES] = { 0x00 },
+ [PERF_COUNT_HW_INSTRUCTIONS] = { 0x01 },
+ [PERF_COUNT_HW_CACHE_REFERENCES] = { 0x08 },
+ [PERF_COUNT_HW_CACHE_MISSES] = { 0x09 },
+ [PERF_COUNT_HW_BRANCH_INSTRUCTIONS] = { 0x02 },
+ [PERF_COUNT_HW_BRANCH_MISSES] = { 0x03 },
+};
+
+static const struct loongarch_perf_event loongson_new_cache_map
+ [PERF_COUNT_HW_CACHE_MAX]
+ [PERF_COUNT_HW_CACHE_OP_MAX]
+ [PERF_COUNT_HW_CACHE_RESULT_MAX] = {
+PERF_CACHE_MAP_ALL_UNSUPPORTED,
+[C(L1D)] = {
+ /*
+ * Like some other architectures (e.g. ARM), the performance
+ * counters don't differentiate between read and write
+ * accesses/misses, so this isn't strictly correct, but it's the
+ * best we can do. Writes and reads get combined.
+ */
+ [C(OP_READ)] = {
+ [C(RESULT_ACCESS)] = { 0x8 },
+ [C(RESULT_MISS)] = { 0x9 },
+ },
+ [C(OP_WRITE)] = {
+ [C(RESULT_ACCESS)] = { 0x8 },
+ [C(RESULT_MISS)] = { 0x9 },
+ },
+ [C(OP_PREFETCH)] = {
+ [C(RESULT_ACCESS)] = { 0xaa },
+ [C(RESULT_MISS)] = { 0xa9 },
+ },
+},
+[C(L1I)] = {
+ [C(OP_READ)] = {
+ [C(RESULT_ACCESS)] = { 0x6 },
+ [C(RESULT_MISS)] = { 0x7 },
+ },
+},
+[C(LL)] = {
+ [C(OP_READ)] = {
+ [C(RESULT_ACCESS)] = { 0xc },
+ [C(RESULT_MISS)] = { 0xd },
+ },
+ [C(OP_WRITE)] = {
+ [C(RESULT_ACCESS)] = { 0xc },
+ [C(RESULT_MISS)] = { 0xd },
+ },
+},
+[C(ITLB)] = {
+ [C(OP_READ)] = {
+ [C(RESULT_MISS)] = { 0x3b },
+ },
+},
+[C(DTLB)] = {
+ [C(OP_READ)] = {
+ [C(RESULT_ACCESS)] = { 0x4 },
+ [C(RESULT_MISS)] = { 0x3c },
+ },
+ [C(OP_WRITE)] = {
+ [C(RESULT_ACCESS)] = { 0x4 },
+ [C(RESULT_MISS)] = { 0x3c },
+ },
+},
+[C(BPU)] = {
+ /* Using the same code for *HW_BRANCH* */
+ [C(OP_READ)] = {
+ [C(RESULT_ACCESS)] = { 0x02 },
+ [C(RESULT_MISS)] = { 0x03 },
+ },
+},
+};
+
+static int __hw_perf_event_init(struct perf_event *event)
+{
+ struct perf_event_attr *attr = &event->attr;
+ struct hw_perf_event *hwc = &event->hw;
+ const struct loongarch_perf_event *pev;
+ int err;
+
+ /* Returning LoongArch event descriptor for generic perf event. */
+ if (PERF_TYPE_HARDWARE == event->attr.type) {
+ if (event->attr.config >= PERF_COUNT_HW_MAX)
+ return -EINVAL;
+ pev = loongarch_pmu_map_general_event(event->attr.config);
+ } else if (PERF_TYPE_HW_CACHE == event->attr.type) {
+ pev = loongarch_pmu_map_cache_event(event->attr.config);
+ } else if (PERF_TYPE_RAW == event->attr.type) {
+ /* We are working on the global raw event. */
+ mutex_lock(&raw_event_mutex);
+ pev = loongarch_pmu.map_raw_event(event->attr.config);
+ } else {
+ /* The event type is not (yet) supported. */
+ return -EOPNOTSUPP;
+ }
+
+ if (IS_ERR(pev)) {
+ if (PERF_TYPE_RAW == event->attr.type)
+ mutex_unlock(&raw_event_mutex);
+ return PTR_ERR(pev);
+ }
+
+ /*
+ * We allow max flexibility on how each individual counter shared
+ * by the single CPU operates (the mode exclusion and the range).
+ */
+ hwc->config_base = CSR_PERFCTRL_IE;
+
+ hwc->event_base = loongarch_pmu_perf_event_encode(pev);
+ if (PERF_TYPE_RAW == event->attr.type)
+ mutex_unlock(&raw_event_mutex);
+
+ if (!attr->exclude_user) {
+ hwc->config_base |= CSR_PERFCTRL_PLV3;
+ hwc->config_base |= CSR_PERFCTRL_PLV2;
+ }
+ if (!attr->exclude_kernel) {
+ hwc->config_base |= CSR_PERFCTRL_PLV0;
+ }
+ if (!attr->exclude_hv) {
+ hwc->config_base |= CSR_PERFCTRL_PLV1;
+ }
+
+ hwc->config_base &= M_PERFCTL_CONFIG_MASK;
+ /*
+ * The event can belong to another cpu. We do not assign a local
+ * counter for it for now.
+ */
+ hwc->idx = -1;
+ hwc->config = 0;
+
+ if (!hwc->sample_period) {
+ hwc->sample_period = loongarch_pmu.max_period;
+ hwc->last_period = hwc->sample_period;
+ local64_set(&hwc->period_left, hwc->sample_period);
+ }
+
+ err = 0;
+ if (event->group_leader != event)
+ err = validate_group(event);
+
+ event->destroy = hw_perf_event_destroy;
+
+ if (err)
+ event->destroy(event);
+
+ return err;
+}
+
+static void pause_local_counters(void)
+{
+ struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
+ int ctr = loongarch_pmu.num_counters;
+ unsigned long flags;
+
+ local_irq_save(flags);
+ do {
+ ctr--;
+ cpuc->saved_ctrl[ctr] = loongarch_pmu_read_control(ctr);
+ loongarch_pmu_write_control(ctr, cpuc->saved_ctrl[ctr] &
+ ~M_PERFCTL_COUNT_EVENT_WHENEVER);
+ } while (ctr > 0);
+ local_irq_restore(flags);
+}
+
+static void resume_local_counters(void)
+{
+ struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
+ int ctr = loongarch_pmu.num_counters;
+
+ do {
+ ctr--;
+ loongarch_pmu_write_control(ctr, cpuc->saved_ctrl[ctr]);
+ } while (ctr > 0);
+}
+
+static const struct loongarch_perf_event *loongarch_pmu_map_raw_event(u64 config)
+{
+ raw_event.event_id = config & 0xff;
+
+ return &raw_event;
+}
+
+static int __init
+init_hw_perf_events(void)
+{
+ int counters = 4;
+
+ if (!cpu_has_pmp)
+ return -ENODEV;
+
+ pr_info("Performance counters: ");
+
+ loongarch_pmu.num_counters = counters;
+ loongarch_pmu.max_period = (1ULL << 63) - 1;
+ loongarch_pmu.valid_count = (1ULL << 63) - 1;
+ loongarch_pmu.overflow = 1ULL << 63;
+ loongarch_pmu.name = "loongarch/loongson64";
+ loongarch_pmu.read_counter = loongarch_pmu_read_counter;
+ loongarch_pmu.write_counter = loongarch_pmu_write_counter;
+ loongarch_pmu.map_raw_event = loongarch_pmu_map_raw_event;
+ loongarch_pmu.general_event_map = &loongson_new_event_map;
+ loongarch_pmu.cache_event_map = &loongson_new_cache_map;
+
+ on_each_cpu(reset_counters, (void *)(long)counters, 1);
+
+ pr_cont("%s PMU enabled, %d %d-bit counters available to each "
+ "CPU.\n", loongarch_pmu.name, counters, 64);
+
+ perf_pmu_register(&pmu, "cpu", PERF_TYPE_RAW);
+
+ return 0;
+}
+early_initcall(init_hw_perf_events);
diff --git a/arch/loongarch/kernel/perf_regs.c b/arch/loongarch/kernel/perf_regs.c
new file mode 100644
index 000000000000..a5e9768e8414
--- /dev/null
+++ b/arch/loongarch/kernel/perf_regs.c
@@ -0,0 +1,50 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2022 Loongson Technology Corporation Limited
+ */
+
+#include <linux/perf_event.h>
+
+#include <asm/ptrace.h>
+
+#ifdef CONFIG_32BIT
+u64 perf_reg_abi(struct task_struct *tsk)
+{
+ return PERF_SAMPLE_REGS_ABI_32;
+}
+#else /* Must be CONFIG_64BIT */
+u64 perf_reg_abi(struct task_struct *tsk)
+{
+ if (test_tsk_thread_flag(tsk, TIF_32BIT_REGS))
+ return PERF_SAMPLE_REGS_ABI_32;
+ else
+ return PERF_SAMPLE_REGS_ABI_64;
+}
+#endif /* CONFIG_32BIT */
+
+int perf_reg_validate(u64 mask)
+{
+ if (!mask)
+ return -EINVAL;
+ if (mask & ~((1ull << PERF_REG_LOONGARCH_MAX) - 1))
+ return -EINVAL;
+ return 0;
+}
+
+u64 perf_reg_value(struct pt_regs *regs, int idx)
+{
+ if (WARN_ON_ONCE((u32)idx >= PERF_REG_LOONGARCH_MAX))
+ return 0;
+
+ if ((u32)idx == PERF_REG_LOONGARCH_PC)
+ return regs->csr_era;
+
+ return regs->regs[idx];
+}
+
+void perf_get_regs_user(struct perf_regs *regs_user,
+ struct pt_regs *regs)
+{
+ regs_user->regs = task_pt_regs(current);
+ regs_user->abi = perf_reg_abi(current);
+}
--
2.31.1
On 2022/8/15 20:47, Huacai Chen wrote:
> Signed-off-by: Huacai Chen <[email protected]>
> ---
> arch/loongarch/Kconfig | 2 +
> arch/loongarch/include/uapi/asm/perf_regs.h | 40 +
> arch/loongarch/kernel/Makefile | 2 +
> arch/loongarch/kernel/perf_event.c | 909 ++++++++++++++++++++
> arch/loongarch/kernel/perf_regs.c | 50 ++
> 5 files changed, 1003 insertions(+)
> create mode 100644 arch/loongarch/include/uapi/asm/perf_regs.h
> create mode 100644 arch/loongarch/kernel/perf_event.c
> create mode 100644 arch/loongarch/kernel/perf_regs.c
The code seems mostly ripped from arch/mips/kernel/perf_event_mipsxx.c.
I reviewed about half of the code then suddenly realized I might be
looking at MIPS code, given some of the English strings there seemed way
too "natural"...
But unfortunately, at least for 3A5000 whose micro-architecture is
largely shared with the MIPS-implementing 3A4000, it seems inevitable to
involve some of the more MIPS-looking logic. The 1st-generation LA
privileged architecture is way too much MIPS-like after all, so if we
want any support for the 3A5000 we'd have to include this.
>
> diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
> index 24665808cf3d..9478f9646fa5 100644
> --- a/arch/loongarch/Kconfig
> +++ b/arch/loongarch/Kconfig
> @@ -93,6 +93,8 @@ config LOONGARCH
> select HAVE_NMI
> select HAVE_PCI
> select HAVE_PERF_EVENTS
> + select HAVE_PERF_REGS
> + select HAVE_PERF_USER_STACK_DUMP
> select HAVE_REGS_AND_STACK_ACCESS_API
> select HAVE_RSEQ
> select HAVE_SETUP_PER_CPU_AREA if NUMA
> diff --git a/arch/loongarch/include/uapi/asm/perf_regs.h b/arch/loongarch/include/uapi/asm/perf_regs.h
> new file mode 100644
> index 000000000000..9943d418e01d
> --- /dev/null
> +++ b/arch/loongarch/include/uapi/asm/perf_regs.h
> @@ -0,0 +1,40 @@
> +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
> +#ifndef _ASM_LOONGARCH_PERF_REGS_H
> +#define _ASM_LOONGARCH_PERF_REGS_H
> +
> +enum perf_event_loongarch_regs {
> + PERF_REG_LOONGARCH_PC,
> + PERF_REG_LOONGARCH_R1,
> + PERF_REG_LOONGARCH_R2,
> + PERF_REG_LOONGARCH_R3,
> + PERF_REG_LOONGARCH_R4,
> + PERF_REG_LOONGARCH_R5,
> + PERF_REG_LOONGARCH_R6,
> + PERF_REG_LOONGARCH_R7,
> + PERF_REG_LOONGARCH_R8,
> + PERF_REG_LOONGARCH_R9,
> + PERF_REG_LOONGARCH_R10,
> + PERF_REG_LOONGARCH_R11,
> + PERF_REG_LOONGARCH_R12,
> + PERF_REG_LOONGARCH_R13,
> + PERF_REG_LOONGARCH_R14,
> + PERF_REG_LOONGARCH_R15,
> + PERF_REG_LOONGARCH_R16,
> + PERF_REG_LOONGARCH_R17,
> + PERF_REG_LOONGARCH_R18,
> + PERF_REG_LOONGARCH_R19,
> + PERF_REG_LOONGARCH_R20,
> + PERF_REG_LOONGARCH_R21,
> + PERF_REG_LOONGARCH_R22,
> + PERF_REG_LOONGARCH_R23,
> + PERF_REG_LOONGARCH_R24,
> + PERF_REG_LOONGARCH_R25,
> + PERF_REG_LOONGARCH_R26,
> + PERF_REG_LOONGARCH_R27,
> + PERF_REG_LOONGARCH_R28,
> + PERF_REG_LOONGARCH_R29,
> + PERF_REG_LOONGARCH_R30,
> + PERF_REG_LOONGARCH_R31,
> + PERF_REG_LOONGARCH_MAX = PERF_REG_LOONGARCH_R31 + 1,
No need for this "PERF_REG_LOONGARCH_R31 + 1" because it's what happens
without the assignment anyway?
> +};
> +#endif /* _ASM_LOONGARCH_PERF_REGS_H */
> diff --git a/arch/loongarch/kernel/Makefile b/arch/loongarch/kernel/Makefile
> index e5be17009fe8..a213e994db68 100644
> --- a/arch/loongarch/kernel/Makefile
> +++ b/arch/loongarch/kernel/Makefile
> @@ -26,4 +26,6 @@ obj-$(CONFIG_NUMA) += numa.o
> obj-$(CONFIG_UNWINDER_GUESS) += unwind_guess.o
> obj-$(CONFIG_UNWINDER_PROLOGUE) += unwind_prologue.o
>
> +obj-$(CONFIG_PERF_EVENTS) += perf_event.o perf_regs.o
> +
> CPPFLAGS_vmlinux.lds := $(KBUILD_CFLAGS)
> diff --git a/arch/loongarch/kernel/perf_event.c b/arch/loongarch/kernel/perf_event.c
> new file mode 100644
> index 000000000000..00cdbcebaf80
> --- /dev/null
> +++ b/arch/loongarch/kernel/perf_event.c
> @@ -0,0 +1,909 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Linux performance counter support for LoongArch.
Please indicate its MIPS origin and copyright info ;-)
> + *
> + * Copyright (C) 2022 Loongson Technology Corporation Limited
> + */
> +
> +#include <linux/cpumask.h>
> +#include <linux/interrupt.h>
> +#include <linux/smp.h>
> +#include <linux/kernel.h>
> +#include <linux/perf_event.h>
> +#include <linux/uaccess.h>
> +#include <linux/sched/task_stack.h>
> +
> +#include <asm/irq.h>
> +#include <asm/irq_regs.h>
> +#include <asm/stacktrace.h>
> +#include <asm/unwind.h>
> +
> +/*
> + * Get the return address for a single stackframe and return a pointer to the
> + * next frame tail.
> + */
> +static unsigned long
> +user_backtrace(struct perf_callchain_entry_ctx *entry, unsigned long fp)
> +{
> + struct stack_frame buftail;
> + unsigned long err;
> + unsigned long __user *user_frame_tail = (unsigned long *)(fp - sizeof(struct stack_frame));
> +
> + /* Also check accessibility of one struct frame_tail beyond */
> + if (!access_ok(user_frame_tail, sizeof(buftail)))
> + return 0;
> +
> + pagefault_disable();
> + err = __copy_from_user_inatomic(&buftail, user_frame_tail, sizeof(buftail));
> + pagefault_enable();
> +
> + if (err || (unsigned long)user_frame_tail >= buftail.fp)
> + return 0;
> +
> + perf_callchain_store(entry, buftail.ra);
> +
> + return buftail.fp;
> +}
> +
> +void perf_callchain_user(struct perf_callchain_entry_ctx *entry,
> + struct pt_regs *regs)
> +{
> + unsigned long fp;
> +
> + if (perf_guest_state()) {
> + /* We don't support guest os callchain now */
> + return;
> + }
> +
> + perf_callchain_store(entry, regs->csr_era);
> +
> + fp = regs->regs[22];
> +
> + while (entry->nr < entry->max_stack && fp && !((unsigned long)fp & 0xf))
> + fp = user_backtrace(entry, fp);
> +}
> +
> +void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry,
> + struct pt_regs *regs)
> +{
> + struct unwind_state state;
> + unsigned long addr;
> +
> + for (unwind_start(&state, current, regs);
> + !unwind_done(&state); unwind_next_frame(&state)) {
> + addr = unwind_get_return_address(&state);
> + if (!addr || perf_callchain_store(entry, addr))
> + return;
> + }
> +}
> +
> +#define LOONGARCH_MAX_HWEVENTS 4
> +
> +struct cpu_hw_events {
> + /* Array of events on this cpu. */
> + struct perf_event *events[LOONGARCH_MAX_HWEVENTS];
> +
> + /*
> + * Set the bit (indexed by the counter number) when the counter
> + * is used for an event.
> + */
> + unsigned long used_mask[BITS_TO_LONGS(LOONGARCH_MAX_HWEVENTS)];
> +
> + /*
> + * Software copy of the control register for each performance counter.
> + * LoongArch CPUs vary in performance counters. They use this differently,
> + * and even may not use it.
I can't easily make sense of the paragraph. "Software copy" could mean
"Saved copy", but how do "use differently" and "even may not use it"
mean? For the latter I can't deduce if it's originally "some even may
not exist" in someone's head, and for the former I can't imagine what's
the possible cases and why we would care.
Maybe explain a little bit more?
> + */
> + unsigned int saved_ctrl[LOONGARCH_MAX_HWEVENTS];
> +};
> +static DEFINE_PER_CPU(struct cpu_hw_events, cpu_hw_events) = {
> + .saved_ctrl = {0},
> +};
> +
> +/* The description of LoongArch performance events. */
> +struct loongarch_perf_event {
> + unsigned int event_id;
> +};
> +
> +static struct loongarch_perf_event raw_event;
> +static DEFINE_MUTEX(raw_event_mutex);
> +
> +#define C(x) PERF_COUNT_HW_CACHE_##x
> +#define HW_OP_UNSUPPORTED 0xffffffff
> +#define CACHE_OP_UNSUPPORTED 0xffffffff
> +
> +#define PERF_MAP_ALL_UNSUPPORTED \
> + [0 ... PERF_COUNT_HW_MAX - 1] = {HW_OP_UNSUPPORTED}
> +
> +#define PERF_CACHE_MAP_ALL_UNSUPPORTED \
> +[0 ... C(MAX) - 1] = { \
> + [0 ... C(OP_MAX) - 1] = { \
> + [0 ... C(RESULT_MAX) - 1] = {CACHE_OP_UNSUPPORTED}, \
> + }, \
> +}
> +
> +struct loongarch_pmu {
> + u64 max_period;
> + u64 valid_count;
> + u64 overflow;
> + const char *name;
> + u64 (*read_counter)(unsigned int idx);
> + void (*write_counter)(unsigned int idx, u64 val);
> + const struct loongarch_perf_event *(*map_raw_event)(u64 config);
> + const struct loongarch_perf_event (*general_event_map)[PERF_COUNT_HW_MAX];
> + const struct loongarch_perf_event (*cache_event_map)
> + [PERF_COUNT_HW_CACHE_MAX]
> + [PERF_COUNT_HW_CACHE_OP_MAX]
> + [PERF_COUNT_HW_CACHE_RESULT_MAX];
Apparently general_event_map and cache_event_map are not function
pointers? So the parens around the field name should be removed.
> + unsigned int num_counters;
> +};
> +
> +static struct loongarch_pmu loongarch_pmu;
> +
> +#define M_PERFCTL_EVENT(event) (event & CSR_PERFCTRL_EVENT)
> +
> +#define M_PERFCTL_COUNT_EVENT_WHENEVER (CSR_PERFCTRL_PLV0 | \
> + CSR_PERFCTRL_PLV1 | \
> + CSR_PERFCTRL_PLV2 | \
> + CSR_PERFCTRL_PLV3 | \
> + CSR_PERFCTRL_IE)
> +
> +#define M_PERFCTL_CONFIG_MASK 0x1f0000
> +
> +#define CNTR_BIT_MASK(n) (((n) == 64) ? ~0ULL : ((1ULL<<(n))-1))
Isn't this just GENMASK(n - 1, 0)?
> +
> +static void resume_local_counters(void);
> +static void pause_local_counters(void);
> +
> +static u64 loongarch_pmu_read_counter(unsigned int idx)
> +{
> + u64 val = -1;
> +
> + switch (idx) {
> + case 0:
> + val = read_csr_perfcntr0();
> + break;
> + case 1:
> + val = read_csr_perfcntr1();
> + break;
> + case 2:
> + val = read_csr_perfcntr2();
> + break;
> + case 3:
> + val = read_csr_perfcntr3();
> + break;
> + default:
> + WARN_ONCE(1, "Invalid performance counter number (%d)\n", idx);
> + return 0;
> + }
> +
> + return val;
> +}
> +
> +static void loongarch_pmu_write_counter(unsigned int idx, u64 val)
> +{
> + switch (idx) {
> + case 0:
> + write_csr_perfcntr0(val);
> + return;
> + case 1:
> + write_csr_perfcntr1(val);
> + return;
> + case 2:
> + write_csr_perfcntr2(val);
> + return;
> + case 3:
> + write_csr_perfcntr3(val);
> + return;
Want a default branch for this function, similar to the read case?
> + }
> +}
> +
> +static unsigned int loongarch_pmu_read_control(unsigned int idx)
> +{
> + unsigned int val = -1;
> +
> + switch (idx) {
> + case 0:
> + val = read_csr_perfctrl0();
> + break;
> + case 1:
> + val = read_csr_perfctrl1();
> + break;
> + case 2:
> + val = read_csr_perfctrl2();
> + break;
> + case 3:
> + val = read_csr_perfctrl3();
> + break;
> + default:
> + WARN_ONCE(1, "Invalid performance counter number (%d)\n", idx);
> + return 0;
> + }
> +
> + return val;
> +}
> +
> +static void loongarch_pmu_write_control(unsigned int idx, unsigned int val)
> +{
> + switch (idx) {
> + case 0:
> + write_csr_perfctrl0(val);
> + return;
> + case 1:
> + write_csr_perfctrl1(val);
> + return;
> + case 2:
> + write_csr_perfctrl2(val);
> + return;
> + case 3:
> + write_csr_perfctrl3(val);
> + return;
Similarly here.
> + }
> +}
> +
> +static int loongarch_pmu_alloc_counter(struct cpu_hw_events *cpuc,
> + struct hw_perf_event *hwc)
> +{
> + int i;
> +
> + for (i = loongarch_pmu.num_counters - 1; i >= 0; i--) {
> + if (!test_and_set_bit(i, cpuc->used_mask))
> + return i;
> + }
> +
> + return -EAGAIN;
> +}
> +
> +static void loongarch_pmu_enable_event(struct hw_perf_event *evt, int idx)
> +{
> + struct perf_event *event = container_of(evt, struct perf_event, hw);
> + struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
> + unsigned int cpu;
> +
> + WARN_ON(idx < 0 || idx >= loongarch_pmu.num_counters);
> +
> + cpuc->saved_ctrl[idx] = M_PERFCTL_EVENT(evt->event_base & 0xff) |
> + (evt->config_base & M_PERFCTL_CONFIG_MASK) |
> + /* Make sure interrupt enabled. */
> + CSR_PERFCTRL_IE;
> +
> + cpu = (event->cpu >= 0) ? event->cpu : smp_processor_id();
> +
> + pr_debug("Enabling perf counter for CPU%d\n", cpu);
> + /*
> + * We do not actually let the counter run. Leave it until start().
> + */
> +}
> +
> +static void loongarch_pmu_disable_event(int idx)
> +{
> + struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
> + unsigned long flags;
> +
> + WARN_ON(idx < 0 || idx >= loongarch_pmu.num_counters);
> +
> + local_irq_save(flags);
> + cpuc->saved_ctrl[idx] = loongarch_pmu_read_control(idx) &
> + ~M_PERFCTL_COUNT_EVENT_WHENEVER;
> + loongarch_pmu_write_control(idx, cpuc->saved_ctrl[idx]);
> + local_irq_restore(flags);
> +}
> +
> +static int loongarch_pmu_event_set_period(struct perf_event *event,
> + struct hw_perf_event *hwc,
> + int idx)
> +{
> + u64 left = local64_read(&hwc->period_left);
> + u64 period = hwc->sample_period;
> + int ret = 0;
> +
> + if (unlikely((left + period) & (1ULL << 63))) {
> + /* left underflowed by more than period. */
> + left = period;
> + local64_set(&hwc->period_left, left);
> + hwc->last_period = period;
> + ret = 1;
> + } else if (unlikely((left + period) <= period)) {
> + /* left underflowed by less than period. */
> + left += period;
> + local64_set(&hwc->period_left, left);
> + hwc->last_period = period;
> + ret = 1;
> + }
> +
> + if (left > loongarch_pmu.max_period) {
> + left = loongarch_pmu.max_period;
> + local64_set(&hwc->period_left, left);
> + }
> +
> + local64_set(&hwc->prev_count, loongarch_pmu.overflow - left);
> +
> + loongarch_pmu.write_counter(idx, loongarch_pmu.overflow - left);
> +
> + perf_event_update_userpage(event);
> +
> + return ret;
> +}
> +
> +static void loongarch_pmu_event_update(struct perf_event *event,
> + struct hw_perf_event *hwc,
> + int idx)
> +{
> + u64 delta;
> + u64 prev_raw_count, new_raw_count;
> +
> +again:
> + prev_raw_count = local64_read(&hwc->prev_count);
> + new_raw_count = loongarch_pmu.read_counter(idx);
> +
> + if (local64_cmpxchg(&hwc->prev_count, prev_raw_count,
> + new_raw_count) != prev_raw_count)
> + goto again;
> +
> + delta = new_raw_count - prev_raw_count;
> +
> + local64_add(delta, &event->count);
> + local64_sub(delta, &hwc->period_left);
> +}
> +
> +static void loongarch_pmu_start(struct perf_event *event, int flags)
> +{
> + struct hw_perf_event *hwc = &event->hw;
> +
> + if (flags & PERF_EF_RELOAD)
> + WARN_ON_ONCE(!(hwc->state & PERF_HES_UPTODATE));
> +
> + hwc->state = 0;
> +
> + /* Set the period for the event. */
> + loongarch_pmu_event_set_period(event, hwc, hwc->idx);
> +
> + /* Enable the event. */
> + loongarch_pmu_enable_event(hwc, hwc->idx);
> +}
> +
> +static void loongarch_pmu_stop(struct perf_event *event, int flags)
> +{
> + struct hw_perf_event *hwc = &event->hw;
> +
> + if (!(hwc->state & PERF_HES_STOPPED)) {
> + /* We are working on a local event. */
> + loongarch_pmu_disable_event(hwc->idx);
> + barrier();
> + loongarch_pmu_event_update(event, hwc, hwc->idx);
> + hwc->state |= PERF_HES_STOPPED | PERF_HES_UPTODATE;
> + }
> +}
> +
> +static int loongarch_pmu_add(struct perf_event *event, int flags)
> +{
> + struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
> + struct hw_perf_event *hwc = &event->hw;
> + int idx;
> + int err = 0;
> +
> + perf_pmu_disable(event->pmu);
> +
> + /* To look for a free counter for this event. */
> + idx = loongarch_pmu_alloc_counter(cpuc, hwc);
> + if (idx < 0) {
> + err = idx;
> + goto out;
> + }
> +
> + /*
> + * If there is an event in the counter we are going to use then
> + * make sure it is disabled.
> + */
> + event->hw.idx = idx;
> + loongarch_pmu_disable_event(idx);
> + cpuc->events[idx] = event;
> +
> + hwc->state = PERF_HES_STOPPED | PERF_HES_UPTODATE;
> + if (flags & PERF_EF_START)
> + loongarch_pmu_start(event, PERF_EF_RELOAD);
> +
> + /* Propagate our changes to the userspace mapping. */
> + perf_event_update_userpage(event);
> +
> +out:
> + perf_pmu_enable(event->pmu);
> + return err;
> +}
> +
> +static void loongarch_pmu_del(struct perf_event *event, int flags)
> +{
> + struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
> + struct hw_perf_event *hwc = &event->hw;
> + int idx = hwc->idx;
> +
> + WARN_ON(idx < 0 || idx >= loongarch_pmu.num_counters);
> +
> + loongarch_pmu_stop(event, PERF_EF_UPDATE);
> + cpuc->events[idx] = NULL;
> + clear_bit(idx, cpuc->used_mask);
> +
> + perf_event_update_userpage(event);
> +}
> +
> +static void loongarch_pmu_read(struct perf_event *event)
> +{
> + struct hw_perf_event *hwc = &event->hw;
> +
> + /* Don't read disabled counters! */
> + if (hwc->idx < 0)
> + return;
> +
> + loongarch_pmu_event_update(event, hwc, hwc->idx);
> +}
> +
> +static void loongarch_pmu_enable(struct pmu *pmu)
> +{
> + resume_local_counters();
> +}
> +
> +static void loongarch_pmu_disable(struct pmu *pmu)
> +{
> + pause_local_counters();
> +}
> +
> +static atomic_t active_events = ATOMIC_INIT(0);
> +static DEFINE_MUTEX(pmu_reserve_mutex);
> +
> +static void reset_counters(void *arg);
> +static int __hw_perf_event_init(struct perf_event *event);
> +
> +static void hw_perf_event_destroy(struct perf_event *event)
> +{
> + if (atomic_dec_and_mutex_lock(&active_events,
> + &pmu_reserve_mutex)) {
> + /*
> + * We must not call the destroy function with interrupts
> + * disabled.
> + */
> + on_each_cpu(reset_counters,
> + (void *)(long)loongarch_pmu.num_counters, 1);
> + mutex_unlock(&pmu_reserve_mutex);
> + }
> +}
> +
> +/* This is needed by specific irq handlers in perf_event_*.c */
> +static void handle_associated_event(struct cpu_hw_events *cpuc,
> + int idx, struct perf_sample_data *data,
> + struct pt_regs *regs)
> +{
> + struct perf_event *event = cpuc->events[idx];
> + struct hw_perf_event *hwc = &event->hw;
> +
> + loongarch_pmu_event_update(event, hwc, idx);
> + data->period = event->hw.last_period;
> + if (!loongarch_pmu_event_set_period(event, hwc, idx))
> + return;
> +
> + if (perf_event_overflow(event, data, regs))
> + loongarch_pmu_disable_event(idx);
> +}
> +
> +static irqreturn_t pmu_handle_irq(int irq, void *dev)
> +{
> + int handled = IRQ_NONE;
> + unsigned int counters = loongarch_pmu.num_counters;
> + u64 counter;
> + struct pt_regs *regs;
> + struct perf_sample_data data;
> + struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
> +
> + /*
> + * First we pause the local counters, so that when we are locked
> + * here, the counters are all paused. When it gets locked due to
> + * perf_disable(), the timer interrupt handler will be delayed.
> + *
> + * See also loongarch_pmu_start().
> + */
> + pause_local_counters();
> +
> + regs = get_irq_regs();
> +
> + perf_sample_data_init(&data, 0, 0);
> +
> + switch (counters) {
> +#define HANDLE_COUNTER(n) \
> + case n + 1: \
> + if (test_bit(n, cpuc->used_mask)) { \
> + counter = loongarch_pmu.read_counter(n); \
> + if (counter & loongarch_pmu.overflow) { \
> + handle_associated_event(cpuc, n, &data, regs); \
> + handled = IRQ_HANDLED; \
> + } \
> + }
> + HANDLE_COUNTER(3)
> + fallthrough;
> + HANDLE_COUNTER(2)
> + fallthrough;
> + HANDLE_COUNTER(1)
> + fallthrough;
> + HANDLE_COUNTER(0)
> + }
> +
> + resume_local_counters();
> +
> + /*
> + * Do all the work for the pending perf events. We can do this
> + * in here because the performance counter interrupt is a regular
> + * interrupt, not NMI.
> + */
> + if (handled == IRQ_HANDLED)
> + irq_work_run();
> +
> + return handled;
> +}
> +
> +static int get_pmc_irq(void)
> +{
> + struct irq_domain *d = irq_find_matching_fwnode(cpuintc_handle, DOMAIN_BUS_ANY);
> +
> + if (d)
> + return irq_create_mapping(d, EXCCODE_PMC - EXCCODE_INT_START);
> +
> + return -EINVAL;
> +}
> +
> +static int loongarch_pmu_event_init(struct perf_event *event)
> +{
> + int r, irq;
> + unsigned long flags;
> +
> + /* does not support taken branch sampling */
> + if (has_branch_stack(event))
> + return -EOPNOTSUPP;
> +
> + switch (event->attr.type) {
> + case PERF_TYPE_RAW:
> + case PERF_TYPE_HARDWARE:
> + case PERF_TYPE_HW_CACHE:
> + break;
> +
> + default:
> + /* Init it to avoid false validate_group */
> + event->hw.event_base = 0xffffffff;
> + return -ENOENT;
> + }
> +
> + if (event->cpu >= 0 && !cpu_online(event->cpu))
> + return -ENODEV;
> +
> + irq = get_pmc_irq();
> + flags = IRQF_PERCPU | IRQF_NOBALANCING | IRQF_NO_THREAD | IRQF_NO_SUSPEND | IRQF_SHARED;
> + if (!atomic_inc_not_zero(&active_events)) {
> + mutex_lock(&pmu_reserve_mutex);
> + if (atomic_read(&active_events) == 0) {
> + r = request_irq(irq, pmu_handle_irq,
> + flags, "Perf_PMU", &loongarch_pmu);
> + if (r < 0) {
> + pr_warn("PMU IRQ request failed\n");
> + return -ENODEV;
> + }
> + }
> + atomic_inc(&active_events);
> + mutex_unlock(&pmu_reserve_mutex);
> + }
> +
> + return __hw_perf_event_init(event);
> +}
> +
> +static struct pmu pmu = {
> + .pmu_enable = loongarch_pmu_enable,
> + .pmu_disable = loongarch_pmu_disable,
> + .event_init = loongarch_pmu_event_init,
> + .add = loongarch_pmu_add,
> + .del = loongarch_pmu_del,
> + .start = loongarch_pmu_start,
> + .stop = loongarch_pmu_stop,
> + .read = loongarch_pmu_read,
> +};
> +
> +static unsigned int loongarch_pmu_perf_event_encode(const struct loongarch_perf_event *pev)
> +{
> + return (pev->event_id & 0xff);
> +}
> +
> +static const struct loongarch_perf_event *loongarch_pmu_map_general_event(int idx)
> +{
> + const struct loongarch_perf_event *pev;
> +
> + pev = &(*loongarch_pmu.general_event_map)[idx];
> +
> + if (pev->event_id == HW_OP_UNSUPPORTED)
> + return ERR_PTR(-ENOENT);
> +
> + return pev;
> +}
> +
> +static const struct loongarch_perf_event *loongarch_pmu_map_cache_event(u64 config)
> +{
> + unsigned int cache_type, cache_op, cache_result;
> + const struct loongarch_perf_event *pev;
> +
> + cache_type = (config >> 0) & 0xff;
> + if (cache_type >= PERF_COUNT_HW_CACHE_MAX)
> + return ERR_PTR(-EINVAL);
> +
> + cache_op = (config >> 8) & 0xff;
> + if (cache_op >= PERF_COUNT_HW_CACHE_OP_MAX)
> + return ERR_PTR(-EINVAL);
> +
> + cache_result = (config >> 16) & 0xff;
> + if (cache_result >= PERF_COUNT_HW_CACHE_RESULT_MAX)
> + return ERR_PTR(-EINVAL);
> +
> + pev = &((*loongarch_pmu.cache_event_map)
> + [cache_type]
> + [cache_op]
> + [cache_result]);
> +
> + if (pev->event_id == CACHE_OP_UNSUPPORTED)
> + return ERR_PTR(-ENOENT);
> +
> + return pev;
> +}
> +
> +static int validate_group(struct perf_event *event)
> +{
> + struct perf_event *sibling, *leader = event->group_leader;
> + struct cpu_hw_events fake_cpuc;
> +
> + memset(&fake_cpuc, 0, sizeof(fake_cpuc));
> +
> + if (loongarch_pmu_alloc_counter(&fake_cpuc, &leader->hw) < 0)
> + return -EINVAL;
> +
> + for_each_sibling_event(sibling, leader) {
> + if (loongarch_pmu_alloc_counter(&fake_cpuc, &sibling->hw) < 0)
> + return -EINVAL;
> + }
> +
> + if (loongarch_pmu_alloc_counter(&fake_cpuc, &event->hw) < 0)
> + return -EINVAL;
> +
> + return 0;
> +}
> +
> +static void reset_counters(void *arg)
> +{
> + int counters = (int)(long)arg;
> +
> + switch (counters) {
> + case 4:
> + loongarch_pmu_write_control(3, 0);
> + loongarch_pmu.write_counter(3, 0);
> + fallthrough;
> + case 3:
> + loongarch_pmu_write_control(2, 0);
> + loongarch_pmu.write_counter(2, 0);
> + fallthrough;
> + case 2:
> + loongarch_pmu_write_control(1, 0);
> + loongarch_pmu.write_counter(1, 0);
> + fallthrough;
> + case 1:
> + loongarch_pmu_write_control(0, 0);
> + loongarch_pmu.write_counter(0, 0);
> + }
> +}
> +
> +static const struct loongarch_perf_event loongson_new_event_map[PERF_COUNT_HW_MAX] = {
> + PERF_MAP_ALL_UNSUPPORTED,
> + [PERF_COUNT_HW_CPU_CYCLES] = { 0x00 },
> + [PERF_COUNT_HW_INSTRUCTIONS] = { 0x01 },
> + [PERF_COUNT_HW_CACHE_REFERENCES] = { 0x08 },
> + [PERF_COUNT_HW_CACHE_MISSES] = { 0x09 },
> + [PERF_COUNT_HW_BRANCH_INSTRUCTIONS] = { 0x02 },
> + [PERF_COUNT_HW_BRANCH_MISSES] = { 0x03 },
> +};
> +
> +static const struct loongarch_perf_event loongson_new_cache_map
> + [PERF_COUNT_HW_CACHE_MAX]
> + [PERF_COUNT_HW_CACHE_OP_MAX]
> + [PERF_COUNT_HW_CACHE_RESULT_MAX] = {
> +PERF_CACHE_MAP_ALL_UNSUPPORTED,
> +[C(L1D)] = {
> + /*
> + * Like some other architectures (e.g. ARM), the performance
> + * counters don't differentiate between read and write
> + * accesses/misses, so this isn't strictly correct, but it's the
> + * best we can do. Writes and reads get combined.
> + */
> + [C(OP_READ)] = {
> + [C(RESULT_ACCESS)] = { 0x8 },
> + [C(RESULT_MISS)] = { 0x9 },
> + },
> + [C(OP_WRITE)] = {
> + [C(RESULT_ACCESS)] = { 0x8 },
> + [C(RESULT_MISS)] = { 0x9 },
> + },
> + [C(OP_PREFETCH)] = {
> + [C(RESULT_ACCESS)] = { 0xaa },
> + [C(RESULT_MISS)] = { 0xa9 },
> + },
> +},
> +[C(L1I)] = {
> + [C(OP_READ)] = {
> + [C(RESULT_ACCESS)] = { 0x6 },
> + [C(RESULT_MISS)] = { 0x7 },
> + },
> +},
> +[C(LL)] = {
> + [C(OP_READ)] = {
> + [C(RESULT_ACCESS)] = { 0xc },
> + [C(RESULT_MISS)] = { 0xd },
> + },
> + [C(OP_WRITE)] = {
> + [C(RESULT_ACCESS)] = { 0xc },
> + [C(RESULT_MISS)] = { 0xd },
> + },
> +},
> +[C(ITLB)] = {
> + [C(OP_READ)] = {
> + [C(RESULT_MISS)] = { 0x3b },
> + },
> +},
> +[C(DTLB)] = {
> + [C(OP_READ)] = {
> + [C(RESULT_ACCESS)] = { 0x4 },
> + [C(RESULT_MISS)] = { 0x3c },
> + },
> + [C(OP_WRITE)] = {
> + [C(RESULT_ACCESS)] = { 0x4 },
> + [C(RESULT_MISS)] = { 0x3c },
> + },
> +},
> +[C(BPU)] = {
> + /* Using the same code for *HW_BRANCH* */
> + [C(OP_READ)] = {
> + [C(RESULT_ACCESS)] = { 0x02 },
> + [C(RESULT_MISS)] = { 0x03 },
> + },
> +},
> +};
> +
> +static int __hw_perf_event_init(struct perf_event *event)
> +{
> + struct perf_event_attr *attr = &event->attr;
> + struct hw_perf_event *hwc = &event->hw;
> + const struct loongarch_perf_event *pev;
> + int err;
> +
> + /* Returning LoongArch event descriptor for generic perf event. */
> + if (PERF_TYPE_HARDWARE == event->attr.type) {
> + if (event->attr.config >= PERF_COUNT_HW_MAX)
> + return -EINVAL;
> + pev = loongarch_pmu_map_general_event(event->attr.config);
> + } else if (PERF_TYPE_HW_CACHE == event->attr.type) {
> + pev = loongarch_pmu_map_cache_event(event->attr.config);
> + } else if (PERF_TYPE_RAW == event->attr.type) {
> + /* We are working on the global raw event. */
> + mutex_lock(&raw_event_mutex);
> + pev = loongarch_pmu.map_raw_event(event->attr.config);
> + } else {
> + /* The event type is not (yet) supported. */
> + return -EOPNOTSUPP;
> + }
> +
> + if (IS_ERR(pev)) {
> + if (PERF_TYPE_RAW == event->attr.type)
> + mutex_unlock(&raw_event_mutex);
> + return PTR_ERR(pev);
> + }
> +
> + /*
> + * We allow max flexibility on how each individual counter shared
> + * by the single CPU operates (the mode exclusion and the range).
> + */
> + hwc->config_base = CSR_PERFCTRL_IE;
> +
> + hwc->event_base = loongarch_pmu_perf_event_encode(pev);
> + if (PERF_TYPE_RAW == event->attr.type)
> + mutex_unlock(&raw_event_mutex);
> +
> + if (!attr->exclude_user) {
> + hwc->config_base |= CSR_PERFCTRL_PLV3;
> + hwc->config_base |= CSR_PERFCTRL_PLV2;
> + }
> + if (!attr->exclude_kernel) {
> + hwc->config_base |= CSR_PERFCTRL_PLV0;
> + }
> + if (!attr->exclude_hv) {
> + hwc->config_base |= CSR_PERFCTRL_PLV1;
> + }
> +
> + hwc->config_base &= M_PERFCTL_CONFIG_MASK;
> + /*
> + * The event can belong to another cpu. We do not assign a local
> + * counter for it for now.
> + */
> + hwc->idx = -1;
> + hwc->config = 0;
> +
> + if (!hwc->sample_period) {
> + hwc->sample_period = loongarch_pmu.max_period;
> + hwc->last_period = hwc->sample_period;
> + local64_set(&hwc->period_left, hwc->sample_period);
> + }
> +
> + err = 0;
> + if (event->group_leader != event)
> + err = validate_group(event);
> +
> + event->destroy = hw_perf_event_destroy;
> +
> + if (err)
> + event->destroy(event);
> +
> + return err;
> +}
> +
> +static void pause_local_counters(void)
> +{
> + struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
> + int ctr = loongarch_pmu.num_counters;
> + unsigned long flags;
> +
> + local_irq_save(flags);
> + do {
> + ctr--;
> + cpuc->saved_ctrl[ctr] = loongarch_pmu_read_control(ctr);
> + loongarch_pmu_write_control(ctr, cpuc->saved_ctrl[ctr] &
> + ~M_PERFCTL_COUNT_EVENT_WHENEVER);
> + } while (ctr > 0);
> + local_irq_restore(flags);
> +}
> +
> +static void resume_local_counters(void)
> +{
> + struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
> + int ctr = loongarch_pmu.num_counters;
> +
> + do {
> + ctr--;
> + loongarch_pmu_write_control(ctr, cpuc->saved_ctrl[ctr]);
> + } while (ctr > 0);
> +}
> +
> +static const struct loongarch_perf_event *loongarch_pmu_map_raw_event(u64 config)
> +{
> + raw_event.event_id = config & 0xff;
> +
> + return &raw_event;
> +}
> +
> +static int __init
> +init_hw_perf_events(void)
> +{
> + int counters = 4;
> +
> + if (!cpu_has_pmp)
> + return -ENODEV;
> +
> + pr_info("Performance counters: ");
> +
> + loongarch_pmu.num_counters = counters;
> + loongarch_pmu.max_period = (1ULL << 63) - 1;
> + loongarch_pmu.valid_count = (1ULL << 63) - 1;
> + loongarch_pmu.overflow = 1ULL << 63;
> + loongarch_pmu.name = "loongarch/loongson64";
> + loongarch_pmu.read_counter = loongarch_pmu_read_counter;
> + loongarch_pmu.write_counter = loongarch_pmu_write_counter;
> + loongarch_pmu.map_raw_event = loongarch_pmu_map_raw_event;
> + loongarch_pmu.general_event_map = &loongson_new_event_map;
> + loongarch_pmu.cache_event_map = &loongson_new_cache_map;
> +
> + on_each_cpu(reset_counters, (void *)(long)counters, 1);
> +
> + pr_cont("%s PMU enabled, %d %d-bit counters available to each "
> + "CPU.\n", loongarch_pmu.name, counters, 64);
> +
> + perf_pmu_register(&pmu, "cpu", PERF_TYPE_RAW);
> +
> + return 0;
> +}
> +early_initcall(init_hw_perf_events);
> diff --git a/arch/loongarch/kernel/perf_regs.c b/arch/loongarch/kernel/perf_regs.c
> new file mode 100644
> index 000000000000..a5e9768e8414
> --- /dev/null
> +++ b/arch/loongarch/kernel/perf_regs.c
> @@ -0,0 +1,50 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2022 Loongson Technology Corporation Limited
And this file.
> + */
> +
> +#include <linux/perf_event.h>
> +
> +#include <asm/ptrace.h>
> +
> +#ifdef CONFIG_32BIT
> +u64 perf_reg_abi(struct task_struct *tsk)
> +{
> + return PERF_SAMPLE_REGS_ABI_32;
> +}
> +#else /* Must be CONFIG_64BIT */
> +u64 perf_reg_abi(struct task_struct *tsk)
> +{
> + if (test_tsk_thread_flag(tsk, TIF_32BIT_REGS))
> + return PERF_SAMPLE_REGS_ABI_32;
> + else
> + return PERF_SAMPLE_REGS_ABI_64;
> +}
> +#endif /* CONFIG_32BIT */
> +
> +int perf_reg_validate(u64 mask)
> +{
> + if (!mask)
> + return -EINVAL;
> + if (mask & ~((1ull << PERF_REG_LOONGARCH_MAX) - 1))
> + return -EINVAL;
> + return 0;
> +}
> +
> +u64 perf_reg_value(struct pt_regs *regs, int idx)
> +{
> + if (WARN_ON_ONCE((u32)idx >= PERF_REG_LOONGARCH_MAX))
> + return 0;
> +
> + if ((u32)idx == PERF_REG_LOONGARCH_PC)
> + return regs->csr_era;
> +
> + return regs->regs[idx];
> +}
> +
> +void perf_get_regs_user(struct perf_regs *regs_user,
> + struct pt_regs *regs)
> +{
> + regs_user->regs = task_pt_regs(current);
> + regs_user->abi = perf_reg_abi(current);
> +}
--
WANG "xen0n" Xuerui
Linux/LoongArch mailing list: https://lore.kernel.org/loongarch/
Hi, Xuerui,
On Tue, Aug 16, 2022 at 1:46 PM WANG Xuerui <[email protected]> wrote:
>
> On 2022/8/15 20:47, Huacai Chen wrote:
> > Signed-off-by: Huacai Chen <[email protected]>
> > ---
> > arch/loongarch/Kconfig | 2 +
> > arch/loongarch/include/uapi/asm/perf_regs.h | 40 +
> > arch/loongarch/kernel/Makefile | 2 +
> > arch/loongarch/kernel/perf_event.c | 909 ++++++++++++++++++++
> > arch/loongarch/kernel/perf_regs.c | 50 ++
> > 5 files changed, 1003 insertions(+)
> > create mode 100644 arch/loongarch/include/uapi/asm/perf_regs.h
> > create mode 100644 arch/loongarch/kernel/perf_event.c
> > create mode 100644 arch/loongarch/kernel/perf_regs.c
>
> The code seems mostly ripped from arch/mips/kernel/perf_event_mipsxx.c.
> I reviewed about half of the code then suddenly realized I might be
> looking at MIPS code, given some of the English strings there seemed way
> too "natural"...
>
> But unfortunately, at least for 3A5000 whose micro-architecture is
> largely shared with the MIPS-implementing 3A4000, it seems inevitable to
> involve some of the more MIPS-looking logic. The 1st-generation LA
> privileged architecture is way too much MIPS-like after all, so if we
> want any support for the 3A5000 we'd have to include this.
>
> >
> > diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
> > index 24665808cf3d..9478f9646fa5 100644
> > --- a/arch/loongarch/Kconfig
> > +++ b/arch/loongarch/Kconfig
> > @@ -93,6 +93,8 @@ config LOONGARCH
> > select HAVE_NMI
> > select HAVE_PCI
> > select HAVE_PERF_EVENTS
> > + select HAVE_PERF_REGS
> > + select HAVE_PERF_USER_STACK_DUMP
> > select HAVE_REGS_AND_STACK_ACCESS_API
> > select HAVE_RSEQ
> > select HAVE_SETUP_PER_CPU_AREA if NUMA
> > diff --git a/arch/loongarch/include/uapi/asm/perf_regs.h b/arch/loongarch/include/uapi/asm/perf_regs.h
> > new file mode 100644
> > index 000000000000..9943d418e01d
> > --- /dev/null
> > +++ b/arch/loongarch/include/uapi/asm/perf_regs.h
> > @@ -0,0 +1,40 @@
> > +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
> > +#ifndef _ASM_LOONGARCH_PERF_REGS_H
> > +#define _ASM_LOONGARCH_PERF_REGS_H
> > +
> > +enum perf_event_loongarch_regs {
> > + PERF_REG_LOONGARCH_PC,
> > + PERF_REG_LOONGARCH_R1,
> > + PERF_REG_LOONGARCH_R2,
> > + PERF_REG_LOONGARCH_R3,
> > + PERF_REG_LOONGARCH_R4,
> > + PERF_REG_LOONGARCH_R5,
> > + PERF_REG_LOONGARCH_R6,
> > + PERF_REG_LOONGARCH_R7,
> > + PERF_REG_LOONGARCH_R8,
> > + PERF_REG_LOONGARCH_R9,
> > + PERF_REG_LOONGARCH_R10,
> > + PERF_REG_LOONGARCH_R11,
> > + PERF_REG_LOONGARCH_R12,
> > + PERF_REG_LOONGARCH_R13,
> > + PERF_REG_LOONGARCH_R14,
> > + PERF_REG_LOONGARCH_R15,
> > + PERF_REG_LOONGARCH_R16,
> > + PERF_REG_LOONGARCH_R17,
> > + PERF_REG_LOONGARCH_R18,
> > + PERF_REG_LOONGARCH_R19,
> > + PERF_REG_LOONGARCH_R20,
> > + PERF_REG_LOONGARCH_R21,
> > + PERF_REG_LOONGARCH_R22,
> > + PERF_REG_LOONGARCH_R23,
> > + PERF_REG_LOONGARCH_R24,
> > + PERF_REG_LOONGARCH_R25,
> > + PERF_REG_LOONGARCH_R26,
> > + PERF_REG_LOONGARCH_R27,
> > + PERF_REG_LOONGARCH_R28,
> > + PERF_REG_LOONGARCH_R29,
> > + PERF_REG_LOONGARCH_R30,
> > + PERF_REG_LOONGARCH_R31,
> > + PERF_REG_LOONGARCH_MAX = PERF_REG_LOONGARCH_R31 + 1,
>
> No need for this "PERF_REG_LOONGARCH_R31 + 1" because it's what happens
> without the assignment anyway?
PERF_REG_LOONGARCH_MAX is used in perf_events.c
>
> > +};
> > +#endif /* _ASM_LOONGARCH_PERF_REGS_H */
> > diff --git a/arch/loongarch/kernel/Makefile b/arch/loongarch/kernel/Makefile
> > index e5be17009fe8..a213e994db68 100644
> > --- a/arch/loongarch/kernel/Makefile
> > +++ b/arch/loongarch/kernel/Makefile
> > @@ -26,4 +26,6 @@ obj-$(CONFIG_NUMA) += numa.o
> > obj-$(CONFIG_UNWINDER_GUESS) += unwind_guess.o
> > obj-$(CONFIG_UNWINDER_PROLOGUE) += unwind_prologue.o
> >
> > +obj-$(CONFIG_PERF_EVENTS) += perf_event.o perf_regs.o
> > +
> > CPPFLAGS_vmlinux.lds := $(KBUILD_CFLAGS)
> > diff --git a/arch/loongarch/kernel/perf_event.c b/arch/loongarch/kernel/perf_event.c
> > new file mode 100644
> > index 000000000000..00cdbcebaf80
> > --- /dev/null
> > +++ b/arch/loongarch/kernel/perf_event.c
> > @@ -0,0 +1,909 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Linux performance counter support for LoongArch.
>
> Please indicate its MIPS origin and copyright info ;-)
OK, thanks.
>
> > + *
> > + * Copyright (C) 2022 Loongson Technology Corporation Limited
> > + */
> > +
> > +#include <linux/cpumask.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/smp.h>
> > +#include <linux/kernel.h>
> > +#include <linux/perf_event.h>
> > +#include <linux/uaccess.h>
> > +#include <linux/sched/task_stack.h>
> > +
> > +#include <asm/irq.h>
> > +#include <asm/irq_regs.h>
> > +#include <asm/stacktrace.h>
> > +#include <asm/unwind.h>
> > +
> > +/*
> > + * Get the return address for a single stackframe and return a pointer to the
> > + * next frame tail.
> > + */
> > +static unsigned long
> > +user_backtrace(struct perf_callchain_entry_ctx *entry, unsigned long fp)
> > +{
> > + struct stack_frame buftail;
> > + unsigned long err;
> > + unsigned long __user *user_frame_tail = (unsigned long *)(fp - sizeof(struct stack_frame));
> > +
> > + /* Also check accessibility of one struct frame_tail beyond */
> > + if (!access_ok(user_frame_tail, sizeof(buftail)))
> > + return 0;
> > +
> > + pagefault_disable();
> > + err = __copy_from_user_inatomic(&buftail, user_frame_tail, sizeof(buftail));
> > + pagefault_enable();
> > +
> > + if (err || (unsigned long)user_frame_tail >= buftail.fp)
> > + return 0;
> > +
> > + perf_callchain_store(entry, buftail.ra);
> > +
> > + return buftail.fp;
> > +}
> > +
> > +void perf_callchain_user(struct perf_callchain_entry_ctx *entry,
> > + struct pt_regs *regs)
> > +{
> > + unsigned long fp;
> > +
> > + if (perf_guest_state()) {
> > + /* We don't support guest os callchain now */
> > + return;
> > + }
> > +
> > + perf_callchain_store(entry, regs->csr_era);
> > +
> > + fp = regs->regs[22];
> > +
> > + while (entry->nr < entry->max_stack && fp && !((unsigned long)fp & 0xf))
> > + fp = user_backtrace(entry, fp);
> > +}
> > +
> > +void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry,
> > + struct pt_regs *regs)
> > +{
> > + struct unwind_state state;
> > + unsigned long addr;
> > +
> > + for (unwind_start(&state, current, regs);
> > + !unwind_done(&state); unwind_next_frame(&state)) {
> > + addr = unwind_get_return_address(&state);
> > + if (!addr || perf_callchain_store(entry, addr))
> > + return;
> > + }
> > +}
> > +
> > +#define LOONGARCH_MAX_HWEVENTS 4
> > +
> > +struct cpu_hw_events {
> > + /* Array of events on this cpu. */
> > + struct perf_event *events[LOONGARCH_MAX_HWEVENTS];
> > +
> > + /*
> > + * Set the bit (indexed by the counter number) when the counter
> > + * is used for an event.
> > + */
> > + unsigned long used_mask[BITS_TO_LONGS(LOONGARCH_MAX_HWEVENTS)];
> > +
> > + /*
> > + * Software copy of the control register for each performance counter.
> > + * LoongArch CPUs vary in performance counters. They use this differently,
> > + * and even may not use it.
>
> I can't easily make sense of the paragraph. "Software copy" could mean
> "Saved copy", but how do "use differently" and "even may not use it"
> mean? For the latter I can't deduce if it's originally "some even may
> not exist" in someone's head, and for the former I can't imagine what's
> the possible cases and why we would care.
>
> Maybe explain a little bit more?
I think we should remove those useless lines.
>
> > + */
> > + unsigned int saved_ctrl[LOONGARCH_MAX_HWEVENTS];
> > +};
> > +static DEFINE_PER_CPU(struct cpu_hw_events, cpu_hw_events) = {
> > + .saved_ctrl = {0},
> > +};
> > +
> > +/* The description of LoongArch performance events. */
> > +struct loongarch_perf_event {
> > + unsigned int event_id;
> > +};
> > +
> > +static struct loongarch_perf_event raw_event;
> > +static DEFINE_MUTEX(raw_event_mutex);
> > +
> > +#define C(x) PERF_COUNT_HW_CACHE_##x
> > +#define HW_OP_UNSUPPORTED 0xffffffff
> > +#define CACHE_OP_UNSUPPORTED 0xffffffff
> > +
> > +#define PERF_MAP_ALL_UNSUPPORTED \
> > + [0 ... PERF_COUNT_HW_MAX - 1] = {HW_OP_UNSUPPORTED}
> > +
> > +#define PERF_CACHE_MAP_ALL_UNSUPPORTED \
> > +[0 ... C(MAX) - 1] = { \
> > + [0 ... C(OP_MAX) - 1] = { \
> > + [0 ... C(RESULT_MAX) - 1] = {CACHE_OP_UNSUPPORTED}, \
> > + }, \
> > +}
> > +
> > +struct loongarch_pmu {
> > + u64 max_period;
> > + u64 valid_count;
> > + u64 overflow;
> > + const char *name;
> > + u64 (*read_counter)(unsigned int idx);
> > + void (*write_counter)(unsigned int idx, u64 val);
> > + const struct loongarch_perf_event *(*map_raw_event)(u64 config);
> > + const struct loongarch_perf_event (*general_event_map)[PERF_COUNT_HW_MAX];
> > + const struct loongarch_perf_event (*cache_event_map)
> > + [PERF_COUNT_HW_CACHE_MAX]
> > + [PERF_COUNT_HW_CACHE_OP_MAX]
> > + [PERF_COUNT_HW_CACHE_RESULT_MAX];
>
> Apparently general_event_map and cache_event_map are not function
> pointers? So the parens around the field name should be removed.
They are not function pointers, but "array pointers", but we shouldn't
change them to "array to pointers"..
>
> > + unsigned int num_counters;
> > +};
> > +
> > +static struct loongarch_pmu loongarch_pmu;
> > +
> > +#define M_PERFCTL_EVENT(event) (event & CSR_PERFCTRL_EVENT)
> > +
> > +#define M_PERFCTL_COUNT_EVENT_WHENEVER (CSR_PERFCTRL_PLV0 | \
> > + CSR_PERFCTRL_PLV1 | \
> > + CSR_PERFCTRL_PLV2 | \
> > + CSR_PERFCTRL_PLV3 | \
> > + CSR_PERFCTRL_IE)
> > +
> > +#define M_PERFCTL_CONFIG_MASK 0x1f0000
> > +
> > +#define CNTR_BIT_MASK(n) (((n) == 64) ? ~0ULL : ((1ULL<<(n))-1))
>
> Isn't this just GENMASK(n - 1, 0)?
Yes, you are right.
>
> > +
> > +static void resume_local_counters(void);
> > +static void pause_local_counters(void);
> > +
> > +static u64 loongarch_pmu_read_counter(unsigned int idx)
> > +{
> > + u64 val = -1;
> > +
> > + switch (idx) {
> > + case 0:
> > + val = read_csr_perfcntr0();
> > + break;
> > + case 1:
> > + val = read_csr_perfcntr1();
> > + break;
> > + case 2:
> > + val = read_csr_perfcntr2();
> > + break;
> > + case 3:
> > + val = read_csr_perfcntr3();
> > + break;
> > + default:
> > + WARN_ONCE(1, "Invalid performance counter number (%d)\n", idx);
> > + return 0;
> > + }
> > +
> > + return val;
> > +}
> > +
> > +static void loongarch_pmu_write_counter(unsigned int idx, u64 val)
> > +{
> > + switch (idx) {
> > + case 0:
> > + write_csr_perfcntr0(val);
> > + return;
> > + case 1:
> > + write_csr_perfcntr1(val);
> > + return;
> > + case 2:
> > + write_csr_perfcntr2(val);
> > + return;
> > + case 3:
> > + write_csr_perfcntr3(val);
> > + return;
>
> Want a default branch for this function, similar to the read case?
Yes, that is needed.
>
> > + }
> > +}
> > +
> > +static unsigned int loongarch_pmu_read_control(unsigned int idx)
> > +{
> > + unsigned int val = -1;
> > +
> > + switch (idx) {
> > + case 0:
> > + val = read_csr_perfctrl0();
> > + break;
> > + case 1:
> > + val = read_csr_perfctrl1();
> > + break;
> > + case 2:
> > + val = read_csr_perfctrl2();
> > + break;
> > + case 3:
> > + val = read_csr_perfctrl3();
> > + break;
> > + default:
> > + WARN_ONCE(1, "Invalid performance counter number (%d)\n", idx);
> > + return 0;
> > + }
> > +
> > + return val;
> > +}
> > +
> > +static void loongarch_pmu_write_control(unsigned int idx, unsigned int val)
> > +{
> > + switch (idx) {
> > + case 0:
> > + write_csr_perfctrl0(val);
> > + return;
> > + case 1:
> > + write_csr_perfctrl1(val);
> > + return;
> > + case 2:
> > + write_csr_perfctrl2(val);
> > + return;
> > + case 3:
> > + write_csr_perfctrl3(val);
> > + return;
>
> Similarly here.
>
> > + }
> > +}
> > +
> > +static int loongarch_pmu_alloc_counter(struct cpu_hw_events *cpuc,
> > + struct hw_perf_event *hwc)
> > +{
> > + int i;
> > +
> > + for (i = loongarch_pmu.num_counters - 1; i >= 0; i--) {
> > + if (!test_and_set_bit(i, cpuc->used_mask))
> > + return i;
> > + }
> > +
> > + return -EAGAIN;
> > +}
> > +
> > +static void loongarch_pmu_enable_event(struct hw_perf_event *evt, int idx)
> > +{
> > + struct perf_event *event = container_of(evt, struct perf_event, hw);
> > + struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
> > + unsigned int cpu;
> > +
> > + WARN_ON(idx < 0 || idx >= loongarch_pmu.num_counters);
> > +
> > + cpuc->saved_ctrl[idx] = M_PERFCTL_EVENT(evt->event_base & 0xff) |
> > + (evt->config_base & M_PERFCTL_CONFIG_MASK) |
> > + /* Make sure interrupt enabled. */
> > + CSR_PERFCTRL_IE;
> > +
> > + cpu = (event->cpu >= 0) ? event->cpu : smp_processor_id();
> > +
> > + pr_debug("Enabling perf counter for CPU%d\n", cpu);
> > + /*
> > + * We do not actually let the counter run. Leave it until start().
> > + */
> > +}
> > +
> > +static void loongarch_pmu_disable_event(int idx)
> > +{
> > + struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
> > + unsigned long flags;
> > +
> > + WARN_ON(idx < 0 || idx >= loongarch_pmu.num_counters);
> > +
> > + local_irq_save(flags);
> > + cpuc->saved_ctrl[idx] = loongarch_pmu_read_control(idx) &
> > + ~M_PERFCTL_COUNT_EVENT_WHENEVER;
> > + loongarch_pmu_write_control(idx, cpuc->saved_ctrl[idx]);
> > + local_irq_restore(flags);
> > +}
> > +
> > +static int loongarch_pmu_event_set_period(struct perf_event *event,
> > + struct hw_perf_event *hwc,
> > + int idx)
> > +{
> > + u64 left = local64_read(&hwc->period_left);
> > + u64 period = hwc->sample_period;
> > + int ret = 0;
> > +
> > + if (unlikely((left + period) & (1ULL << 63))) {
> > + /* left underflowed by more than period. */
> > + left = period;
> > + local64_set(&hwc->period_left, left);
> > + hwc->last_period = period;
> > + ret = 1;
> > + } else if (unlikely((left + period) <= period)) {
> > + /* left underflowed by less than period. */
> > + left += period;
> > + local64_set(&hwc->period_left, left);
> > + hwc->last_period = period;
> > + ret = 1;
> > + }
> > +
> > + if (left > loongarch_pmu.max_period) {
> > + left = loongarch_pmu.max_period;
> > + local64_set(&hwc->period_left, left);
> > + }
> > +
> > + local64_set(&hwc->prev_count, loongarch_pmu.overflow - left);
> > +
> > + loongarch_pmu.write_counter(idx, loongarch_pmu.overflow - left);
> > +
> > + perf_event_update_userpage(event);
> > +
> > + return ret;
> > +}
> > +
> > +static void loongarch_pmu_event_update(struct perf_event *event,
> > + struct hw_perf_event *hwc,
> > + int idx)
> > +{
> > + u64 delta;
> > + u64 prev_raw_count, new_raw_count;
> > +
> > +again:
> > + prev_raw_count = local64_read(&hwc->prev_count);
> > + new_raw_count = loongarch_pmu.read_counter(idx);
> > +
> > + if (local64_cmpxchg(&hwc->prev_count, prev_raw_count,
> > + new_raw_count) != prev_raw_count)
> > + goto again;
> > +
> > + delta = new_raw_count - prev_raw_count;
> > +
> > + local64_add(delta, &event->count);
> > + local64_sub(delta, &hwc->period_left);
> > +}
> > +
> > +static void loongarch_pmu_start(struct perf_event *event, int flags)
> > +{
> > + struct hw_perf_event *hwc = &event->hw;
> > +
> > + if (flags & PERF_EF_RELOAD)
> > + WARN_ON_ONCE(!(hwc->state & PERF_HES_UPTODATE));
> > +
> > + hwc->state = 0;
> > +
> > + /* Set the period for the event. */
> > + loongarch_pmu_event_set_period(event, hwc, hwc->idx);
> > +
> > + /* Enable the event. */
> > + loongarch_pmu_enable_event(hwc, hwc->idx);
> > +}
> > +
> > +static void loongarch_pmu_stop(struct perf_event *event, int flags)
> > +{
> > + struct hw_perf_event *hwc = &event->hw;
> > +
> > + if (!(hwc->state & PERF_HES_STOPPED)) {
> > + /* We are working on a local event. */
> > + loongarch_pmu_disable_event(hwc->idx);
> > + barrier();
> > + loongarch_pmu_event_update(event, hwc, hwc->idx);
> > + hwc->state |= PERF_HES_STOPPED | PERF_HES_UPTODATE;
> > + }
> > +}
> > +
> > +static int loongarch_pmu_add(struct perf_event *event, int flags)
> > +{
> > + struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
> > + struct hw_perf_event *hwc = &event->hw;
> > + int idx;
> > + int err = 0;
> > +
> > + perf_pmu_disable(event->pmu);
> > +
> > + /* To look for a free counter for this event. */
> > + idx = loongarch_pmu_alloc_counter(cpuc, hwc);
> > + if (idx < 0) {
> > + err = idx;
> > + goto out;
> > + }
> > +
> > + /*
> > + * If there is an event in the counter we are going to use then
> > + * make sure it is disabled.
> > + */
> > + event->hw.idx = idx;
> > + loongarch_pmu_disable_event(idx);
> > + cpuc->events[idx] = event;
> > +
> > + hwc->state = PERF_HES_STOPPED | PERF_HES_UPTODATE;
> > + if (flags & PERF_EF_START)
> > + loongarch_pmu_start(event, PERF_EF_RELOAD);
> > +
> > + /* Propagate our changes to the userspace mapping. */
> > + perf_event_update_userpage(event);
> > +
> > +out:
> > + perf_pmu_enable(event->pmu);
> > + return err;
> > +}
> > +
> > +static void loongarch_pmu_del(struct perf_event *event, int flags)
> > +{
> > + struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
> > + struct hw_perf_event *hwc = &event->hw;
> > + int idx = hwc->idx;
> > +
> > + WARN_ON(idx < 0 || idx >= loongarch_pmu.num_counters);
> > +
> > + loongarch_pmu_stop(event, PERF_EF_UPDATE);
> > + cpuc->events[idx] = NULL;
> > + clear_bit(idx, cpuc->used_mask);
> > +
> > + perf_event_update_userpage(event);
> > +}
> > +
> > +static void loongarch_pmu_read(struct perf_event *event)
> > +{
> > + struct hw_perf_event *hwc = &event->hw;
> > +
> > + /* Don't read disabled counters! */
> > + if (hwc->idx < 0)
> > + return;
> > +
> > + loongarch_pmu_event_update(event, hwc, hwc->idx);
> > +}
> > +
> > +static void loongarch_pmu_enable(struct pmu *pmu)
> > +{
> > + resume_local_counters();
> > +}
> > +
> > +static void loongarch_pmu_disable(struct pmu *pmu)
> > +{
> > + pause_local_counters();
> > +}
> > +
> > +static atomic_t active_events = ATOMIC_INIT(0);
> > +static DEFINE_MUTEX(pmu_reserve_mutex);
> > +
> > +static void reset_counters(void *arg);
> > +static int __hw_perf_event_init(struct perf_event *event);
> > +
> > +static void hw_perf_event_destroy(struct perf_event *event)
> > +{
> > + if (atomic_dec_and_mutex_lock(&active_events,
> > + &pmu_reserve_mutex)) {
> > + /*
> > + * We must not call the destroy function with interrupts
> > + * disabled.
> > + */
> > + on_each_cpu(reset_counters,
> > + (void *)(long)loongarch_pmu.num_counters, 1);
> > + mutex_unlock(&pmu_reserve_mutex);
> > + }
> > +}
> > +
> > +/* This is needed by specific irq handlers in perf_event_*.c */
> > +static void handle_associated_event(struct cpu_hw_events *cpuc,
> > + int idx, struct perf_sample_data *data,
> > + struct pt_regs *regs)
> > +{
> > + struct perf_event *event = cpuc->events[idx];
> > + struct hw_perf_event *hwc = &event->hw;
> > +
> > + loongarch_pmu_event_update(event, hwc, idx);
> > + data->period = event->hw.last_period;
> > + if (!loongarch_pmu_event_set_period(event, hwc, idx))
> > + return;
> > +
> > + if (perf_event_overflow(event, data, regs))
> > + loongarch_pmu_disable_event(idx);
> > +}
> > +
> > +static irqreturn_t pmu_handle_irq(int irq, void *dev)
> > +{
> > + int handled = IRQ_NONE;
> > + unsigned int counters = loongarch_pmu.num_counters;
> > + u64 counter;
> > + struct pt_regs *regs;
> > + struct perf_sample_data data;
> > + struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
> > +
> > + /*
> > + * First we pause the local counters, so that when we are locked
> > + * here, the counters are all paused. When it gets locked due to
> > + * perf_disable(), the timer interrupt handler will be delayed.
> > + *
> > + * See also loongarch_pmu_start().
> > + */
> > + pause_local_counters();
> > +
> > + regs = get_irq_regs();
> > +
> > + perf_sample_data_init(&data, 0, 0);
> > +
> > + switch (counters) {
> > +#define HANDLE_COUNTER(n) \
> > + case n + 1: \
> > + if (test_bit(n, cpuc->used_mask)) { \
> > + counter = loongarch_pmu.read_counter(n); \
> > + if (counter & loongarch_pmu.overflow) { \
> > + handle_associated_event(cpuc, n, &data, regs); \
> > + handled = IRQ_HANDLED; \
> > + } \
> > + }
> > + HANDLE_COUNTER(3)
> > + fallthrough;
> > + HANDLE_COUNTER(2)
> > + fallthrough;
> > + HANDLE_COUNTER(1)
> > + fallthrough;
> > + HANDLE_COUNTER(0)
> > + }
> > +
> > + resume_local_counters();
> > +
> > + /*
> > + * Do all the work for the pending perf events. We can do this
> > + * in here because the performance counter interrupt is a regular
> > + * interrupt, not NMI.
> > + */
> > + if (handled == IRQ_HANDLED)
> > + irq_work_run();
> > +
> > + return handled;
> > +}
> > +
> > +static int get_pmc_irq(void)
> > +{
> > + struct irq_domain *d = irq_find_matching_fwnode(cpuintc_handle, DOMAIN_BUS_ANY);
> > +
> > + if (d)
> > + return irq_create_mapping(d, EXCCODE_PMC - EXCCODE_INT_START);
> > +
> > + return -EINVAL;
> > +}
> > +
> > +static int loongarch_pmu_event_init(struct perf_event *event)
> > +{
> > + int r, irq;
> > + unsigned long flags;
> > +
> > + /* does not support taken branch sampling */
> > + if (has_branch_stack(event))
> > + return -EOPNOTSUPP;
> > +
> > + switch (event->attr.type) {
> > + case PERF_TYPE_RAW:
> > + case PERF_TYPE_HARDWARE:
> > + case PERF_TYPE_HW_CACHE:
> > + break;
> > +
> > + default:
> > + /* Init it to avoid false validate_group */
> > + event->hw.event_base = 0xffffffff;
> > + return -ENOENT;
> > + }
> > +
> > + if (event->cpu >= 0 && !cpu_online(event->cpu))
> > + return -ENODEV;
> > +
> > + irq = get_pmc_irq();
> > + flags = IRQF_PERCPU | IRQF_NOBALANCING | IRQF_NO_THREAD | IRQF_NO_SUSPEND | IRQF_SHARED;
> > + if (!atomic_inc_not_zero(&active_events)) {
> > + mutex_lock(&pmu_reserve_mutex);
> > + if (atomic_read(&active_events) == 0) {
> > + r = request_irq(irq, pmu_handle_irq,
> > + flags, "Perf_PMU", &loongarch_pmu);
> > + if (r < 0) {
> > + pr_warn("PMU IRQ request failed\n");
> > + return -ENODEV;
> > + }
> > + }
> > + atomic_inc(&active_events);
> > + mutex_unlock(&pmu_reserve_mutex);
> > + }
> > +
> > + return __hw_perf_event_init(event);
> > +}
> > +
> > +static struct pmu pmu = {
> > + .pmu_enable = loongarch_pmu_enable,
> > + .pmu_disable = loongarch_pmu_disable,
> > + .event_init = loongarch_pmu_event_init,
> > + .add = loongarch_pmu_add,
> > + .del = loongarch_pmu_del,
> > + .start = loongarch_pmu_start,
> > + .stop = loongarch_pmu_stop,
> > + .read = loongarch_pmu_read,
> > +};
> > +
> > +static unsigned int loongarch_pmu_perf_event_encode(const struct loongarch_perf_event *pev)
> > +{
> > + return (pev->event_id & 0xff);
> > +}
> > +
> > +static const struct loongarch_perf_event *loongarch_pmu_map_general_event(int idx)
> > +{
> > + const struct loongarch_perf_event *pev;
> > +
> > + pev = &(*loongarch_pmu.general_event_map)[idx];
> > +
> > + if (pev->event_id == HW_OP_UNSUPPORTED)
> > + return ERR_PTR(-ENOENT);
> > +
> > + return pev;
> > +}
> > +
> > +static const struct loongarch_perf_event *loongarch_pmu_map_cache_event(u64 config)
> > +{
> > + unsigned int cache_type, cache_op, cache_result;
> > + const struct loongarch_perf_event *pev;
> > +
> > + cache_type = (config >> 0) & 0xff;
> > + if (cache_type >= PERF_COUNT_HW_CACHE_MAX)
> > + return ERR_PTR(-EINVAL);
> > +
> > + cache_op = (config >> 8) & 0xff;
> > + if (cache_op >= PERF_COUNT_HW_CACHE_OP_MAX)
> > + return ERR_PTR(-EINVAL);
> > +
> > + cache_result = (config >> 16) & 0xff;
> > + if (cache_result >= PERF_COUNT_HW_CACHE_RESULT_MAX)
> > + return ERR_PTR(-EINVAL);
> > +
> > + pev = &((*loongarch_pmu.cache_event_map)
> > + [cache_type]
> > + [cache_op]
> > + [cache_result]);
> > +
> > + if (pev->event_id == CACHE_OP_UNSUPPORTED)
> > + return ERR_PTR(-ENOENT);
> > +
> > + return pev;
> > +}
> > +
> > +static int validate_group(struct perf_event *event)
> > +{
> > + struct perf_event *sibling, *leader = event->group_leader;
> > + struct cpu_hw_events fake_cpuc;
> > +
> > + memset(&fake_cpuc, 0, sizeof(fake_cpuc));
> > +
> > + if (loongarch_pmu_alloc_counter(&fake_cpuc, &leader->hw) < 0)
> > + return -EINVAL;
> > +
> > + for_each_sibling_event(sibling, leader) {
> > + if (loongarch_pmu_alloc_counter(&fake_cpuc, &sibling->hw) < 0)
> > + return -EINVAL;
> > + }
> > +
> > + if (loongarch_pmu_alloc_counter(&fake_cpuc, &event->hw) < 0)
> > + return -EINVAL;
> > +
> > + return 0;
> > +}
> > +
> > +static void reset_counters(void *arg)
> > +{
> > + int counters = (int)(long)arg;
> > +
> > + switch (counters) {
> > + case 4:
> > + loongarch_pmu_write_control(3, 0);
> > + loongarch_pmu.write_counter(3, 0);
> > + fallthrough;
> > + case 3:
> > + loongarch_pmu_write_control(2, 0);
> > + loongarch_pmu.write_counter(2, 0);
> > + fallthrough;
> > + case 2:
> > + loongarch_pmu_write_control(1, 0);
> > + loongarch_pmu.write_counter(1, 0);
> > + fallthrough;
> > + case 1:
> > + loongarch_pmu_write_control(0, 0);
> > + loongarch_pmu.write_counter(0, 0);
> > + }
> > +}
> > +
> > +static const struct loongarch_perf_event loongson_new_event_map[PERF_COUNT_HW_MAX] = {
> > + PERF_MAP_ALL_UNSUPPORTED,
> > + [PERF_COUNT_HW_CPU_CYCLES] = { 0x00 },
> > + [PERF_COUNT_HW_INSTRUCTIONS] = { 0x01 },
> > + [PERF_COUNT_HW_CACHE_REFERENCES] = { 0x08 },
> > + [PERF_COUNT_HW_CACHE_MISSES] = { 0x09 },
> > + [PERF_COUNT_HW_BRANCH_INSTRUCTIONS] = { 0x02 },
> > + [PERF_COUNT_HW_BRANCH_MISSES] = { 0x03 },
> > +};
> > +
> > +static const struct loongarch_perf_event loongson_new_cache_map
> > + [PERF_COUNT_HW_CACHE_MAX]
> > + [PERF_COUNT_HW_CACHE_OP_MAX]
> > + [PERF_COUNT_HW_CACHE_RESULT_MAX] = {
> > +PERF_CACHE_MAP_ALL_UNSUPPORTED,
> > +[C(L1D)] = {
> > + /*
> > + * Like some other architectures (e.g. ARM), the performance
> > + * counters don't differentiate between read and write
> > + * accesses/misses, so this isn't strictly correct, but it's the
> > + * best we can do. Writes and reads get combined.
> > + */
> > + [C(OP_READ)] = {
> > + [C(RESULT_ACCESS)] = { 0x8 },
> > + [C(RESULT_MISS)] = { 0x9 },
> > + },
> > + [C(OP_WRITE)] = {
> > + [C(RESULT_ACCESS)] = { 0x8 },
> > + [C(RESULT_MISS)] = { 0x9 },
> > + },
> > + [C(OP_PREFETCH)] = {
> > + [C(RESULT_ACCESS)] = { 0xaa },
> > + [C(RESULT_MISS)] = { 0xa9 },
> > + },
> > +},
> > +[C(L1I)] = {
> > + [C(OP_READ)] = {
> > + [C(RESULT_ACCESS)] = { 0x6 },
> > + [C(RESULT_MISS)] = { 0x7 },
> > + },
> > +},
> > +[C(LL)] = {
> > + [C(OP_READ)] = {
> > + [C(RESULT_ACCESS)] = { 0xc },
> > + [C(RESULT_MISS)] = { 0xd },
> > + },
> > + [C(OP_WRITE)] = {
> > + [C(RESULT_ACCESS)] = { 0xc },
> > + [C(RESULT_MISS)] = { 0xd },
> > + },
> > +},
> > +[C(ITLB)] = {
> > + [C(OP_READ)] = {
> > + [C(RESULT_MISS)] = { 0x3b },
> > + },
> > +},
> > +[C(DTLB)] = {
> > + [C(OP_READ)] = {
> > + [C(RESULT_ACCESS)] = { 0x4 },
> > + [C(RESULT_MISS)] = { 0x3c },
> > + },
> > + [C(OP_WRITE)] = {
> > + [C(RESULT_ACCESS)] = { 0x4 },
> > + [C(RESULT_MISS)] = { 0x3c },
> > + },
> > +},
> > +[C(BPU)] = {
> > + /* Using the same code for *HW_BRANCH* */
> > + [C(OP_READ)] = {
> > + [C(RESULT_ACCESS)] = { 0x02 },
> > + [C(RESULT_MISS)] = { 0x03 },
> > + },
> > +},
> > +};
> > +
> > +static int __hw_perf_event_init(struct perf_event *event)
> > +{
> > + struct perf_event_attr *attr = &event->attr;
> > + struct hw_perf_event *hwc = &event->hw;
> > + const struct loongarch_perf_event *pev;
> > + int err;
> > +
> > + /* Returning LoongArch event descriptor for generic perf event. */
> > + if (PERF_TYPE_HARDWARE == event->attr.type) {
> > + if (event->attr.config >= PERF_COUNT_HW_MAX)
> > + return -EINVAL;
> > + pev = loongarch_pmu_map_general_event(event->attr.config);
> > + } else if (PERF_TYPE_HW_CACHE == event->attr.type) {
> > + pev = loongarch_pmu_map_cache_event(event->attr.config);
> > + } else if (PERF_TYPE_RAW == event->attr.type) {
> > + /* We are working on the global raw event. */
> > + mutex_lock(&raw_event_mutex);
> > + pev = loongarch_pmu.map_raw_event(event->attr.config);
> > + } else {
> > + /* The event type is not (yet) supported. */
> > + return -EOPNOTSUPP;
> > + }
> > +
> > + if (IS_ERR(pev)) {
> > + if (PERF_TYPE_RAW == event->attr.type)
> > + mutex_unlock(&raw_event_mutex);
> > + return PTR_ERR(pev);
> > + }
> > +
> > + /*
> > + * We allow max flexibility on how each individual counter shared
> > + * by the single CPU operates (the mode exclusion and the range).
> > + */
> > + hwc->config_base = CSR_PERFCTRL_IE;
> > +
> > + hwc->event_base = loongarch_pmu_perf_event_encode(pev);
> > + if (PERF_TYPE_RAW == event->attr.type)
> > + mutex_unlock(&raw_event_mutex);
> > +
> > + if (!attr->exclude_user) {
> > + hwc->config_base |= CSR_PERFCTRL_PLV3;
> > + hwc->config_base |= CSR_PERFCTRL_PLV2;
> > + }
> > + if (!attr->exclude_kernel) {
> > + hwc->config_base |= CSR_PERFCTRL_PLV0;
> > + }
> > + if (!attr->exclude_hv) {
> > + hwc->config_base |= CSR_PERFCTRL_PLV1;
> > + }
> > +
> > + hwc->config_base &= M_PERFCTL_CONFIG_MASK;
> > + /*
> > + * The event can belong to another cpu. We do not assign a local
> > + * counter for it for now.
> > + */
> > + hwc->idx = -1;
> > + hwc->config = 0;
> > +
> > + if (!hwc->sample_period) {
> > + hwc->sample_period = loongarch_pmu.max_period;
> > + hwc->last_period = hwc->sample_period;
> > + local64_set(&hwc->period_left, hwc->sample_period);
> > + }
> > +
> > + err = 0;
> > + if (event->group_leader != event)
> > + err = validate_group(event);
> > +
> > + event->destroy = hw_perf_event_destroy;
> > +
> > + if (err)
> > + event->destroy(event);
> > +
> > + return err;
> > +}
> > +
> > +static void pause_local_counters(void)
> > +{
> > + struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
> > + int ctr = loongarch_pmu.num_counters;
> > + unsigned long flags;
> > +
> > + local_irq_save(flags);
> > + do {
> > + ctr--;
> > + cpuc->saved_ctrl[ctr] = loongarch_pmu_read_control(ctr);
> > + loongarch_pmu_write_control(ctr, cpuc->saved_ctrl[ctr] &
> > + ~M_PERFCTL_COUNT_EVENT_WHENEVER);
> > + } while (ctr > 0);
> > + local_irq_restore(flags);
> > +}
> > +
> > +static void resume_local_counters(void)
> > +{
> > + struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
> > + int ctr = loongarch_pmu.num_counters;
> > +
> > + do {
> > + ctr--;
> > + loongarch_pmu_write_control(ctr, cpuc->saved_ctrl[ctr]);
> > + } while (ctr > 0);
> > +}
> > +
> > +static const struct loongarch_perf_event *loongarch_pmu_map_raw_event(u64 config)
> > +{
> > + raw_event.event_id = config & 0xff;
> > +
> > + return &raw_event;
> > +}
> > +
> > +static int __init
> > +init_hw_perf_events(void)
> > +{
> > + int counters = 4;
> > +
> > + if (!cpu_has_pmp)
> > + return -ENODEV;
> > +
> > + pr_info("Performance counters: ");
> > +
> > + loongarch_pmu.num_counters = counters;
> > + loongarch_pmu.max_period = (1ULL << 63) - 1;
> > + loongarch_pmu.valid_count = (1ULL << 63) - 1;
> > + loongarch_pmu.overflow = 1ULL << 63;
> > + loongarch_pmu.name = "loongarch/loongson64";
> > + loongarch_pmu.read_counter = loongarch_pmu_read_counter;
> > + loongarch_pmu.write_counter = loongarch_pmu_write_counter;
> > + loongarch_pmu.map_raw_event = loongarch_pmu_map_raw_event;
> > + loongarch_pmu.general_event_map = &loongson_new_event_map;
> > + loongarch_pmu.cache_event_map = &loongson_new_cache_map;
> > +
> > + on_each_cpu(reset_counters, (void *)(long)counters, 1);
> > +
> > + pr_cont("%s PMU enabled, %d %d-bit counters available to each "
> > + "CPU.\n", loongarch_pmu.name, counters, 64);
> > +
> > + perf_pmu_register(&pmu, "cpu", PERF_TYPE_RAW);
> > +
> > + return 0;
> > +}
> > +early_initcall(init_hw_perf_events);
> > diff --git a/arch/loongarch/kernel/perf_regs.c b/arch/loongarch/kernel/perf_regs.c
> > new file mode 100644
> > index 000000000000..a5e9768e8414
> > --- /dev/null
> > +++ b/arch/loongarch/kernel/perf_regs.c
> > @@ -0,0 +1,50 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Copyright (C) 2022 Loongson Technology Corporation Limited
>
> And this file.
OK, thanks.
Huacai
>
> > + */
> > +
> > +#include <linux/perf_event.h>
> > +
> > +#include <asm/ptrace.h>
> > +
> > +#ifdef CONFIG_32BIT
> > +u64 perf_reg_abi(struct task_struct *tsk)
> > +{
> > + return PERF_SAMPLE_REGS_ABI_32;
> > +}
> > +#else /* Must be CONFIG_64BIT */
> > +u64 perf_reg_abi(struct task_struct *tsk)
> > +{
> > + if (test_tsk_thread_flag(tsk, TIF_32BIT_REGS))
> > + return PERF_SAMPLE_REGS_ABI_32;
> > + else
> > + return PERF_SAMPLE_REGS_ABI_64;
> > +}
> > +#endif /* CONFIG_32BIT */
> > +
> > +int perf_reg_validate(u64 mask)
> > +{
> > + if (!mask)
> > + return -EINVAL;
> > + if (mask & ~((1ull << PERF_REG_LOONGARCH_MAX) - 1))
> > + return -EINVAL;
> > + return 0;
> > +}
> > +
> > +u64 perf_reg_value(struct pt_regs *regs, int idx)
> > +{
> > + if (WARN_ON_ONCE((u32)idx >= PERF_REG_LOONGARCH_MAX))
> > + return 0;
> > +
> > + if ((u32)idx == PERF_REG_LOONGARCH_PC)
> > + return regs->csr_era;
> > +
> > + return regs->regs[idx];
> > +}
> > +
> > +void perf_get_regs_user(struct perf_regs *regs_user,
> > + struct pt_regs *regs)
> > +{
> > + regs_user->regs = task_pt_regs(current);
> > + regs_user->abi = perf_reg_abi(current);
> > +}
>
> --
> WANG "xen0n" Xuerui
>
> Linux/LoongArch mailing list: https://lore.kernel.org/loongarch/
>
Hi Huacai,
I love your patch! Perhaps something to improve:
[auto build test WARNING on linus/master]
[also build test WARNING on v6.0-rc1 next-20220816]
[cannot apply to soc/for-next]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Huacai-Chen/LoongArch-Add-perf-events-support/20220815-204852
base: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 568035b01cfb107af8d2e4bd2fb9aea22cf5b868
config: loongarch-randconfig-s051-20220815 (https://download.01.org/0day-ci/archive/20220816/[email protected]/config)
compiler: loongarch64-linux-gcc (GCC) 12.1.0
reproduce:
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# apt-get install sparse
# sparse version: v0.6.4-39-gce1a6720-dirty
# https://github.com/intel-lab-lkp/linux/commit/0e6d9490ff3f6129799675b9288135022a0908e2
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Huacai-Chen/LoongArch-Add-perf-events-support/20220815-204852
git checkout 0e6d9490ff3f6129799675b9288135022a0908e2
# save the config file
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' ARCH=loongarch
If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <[email protected]>
sparse warnings: (new ones prefixed by >>)
>> arch/loongarch/kernel/perf_event.c:30:50: sparse: sparse: incorrect type in initializer (different address spaces) @@ expected unsigned long [noderef] __user *user_frame_tail @@ got unsigned long * @@
arch/loongarch/kernel/perf_event.c:30:50: sparse: expected unsigned long [noderef] __user *user_frame_tail
arch/loongarch/kernel/perf_event.c:30:50: sparse: got unsigned long *
arch/loongarch/kernel/perf_event.c: note: in included file (through arch/loongarch/include/asm/cpu-info.h, arch/loongarch/include/asm/processor.h, ...):
arch/loongarch/include/asm/loongarch.h:237:16: sparse: sparse: undefined identifier '__builtin_loongarch_csrrd_d'
arch/loongarch/include/asm/loongarch.h:237:16: sparse: sparse: cast from unknown type
arch/loongarch/include/asm/loongarch.h:237:16: sparse: sparse: cast from unknown type
arch/loongarch/include/asm/loongarch.h:237:16: sparse: sparse: cast from unknown type
arch/loongarch/include/asm/loongarch.h:237:16: sparse: sparse: cast from unknown type
arch/loongarch/include/asm/loongarch.h:247:9: sparse: sparse: undefined identifier '__builtin_loongarch_csrwr_d'
arch/loongarch/include/asm/loongarch.h:247:9: sparse: sparse: cast from unknown type
arch/loongarch/include/asm/loongarch.h:247:9: sparse: sparse: cast from unknown type
arch/loongarch/include/asm/loongarch.h:247:9: sparse: sparse: cast from unknown type
arch/loongarch/include/asm/loongarch.h:247:9: sparse: sparse: cast from unknown type
arch/loongarch/include/asm/loongarch.h:237:16: sparse: sparse: cast from unknown type
arch/loongarch/include/asm/loongarch.h:237:16: sparse: sparse: cast from unknown type
arch/loongarch/include/asm/loongarch.h:237:16: sparse: sparse: cast from unknown type
arch/loongarch/include/asm/loongarch.h:237:16: sparse: sparse: cast from unknown type
arch/loongarch/include/asm/loongarch.h:247:9: sparse: sparse: cast from unknown type
arch/loongarch/include/asm/loongarch.h:247:9: sparse: sparse: cast from unknown type
arch/loongarch/include/asm/loongarch.h:247:9: sparse: sparse: cast from unknown type
arch/loongarch/include/asm/loongarch.h:247:9: sparse: sparse: cast from unknown type
vim +30 arch/loongarch/kernel/perf_event.c
20
21 /*
22 * Get the return address for a single stackframe and return a pointer to the
23 * next frame tail.
24 */
25 static unsigned long
26 user_backtrace(struct perf_callchain_entry_ctx *entry, unsigned long fp)
27 {
28 struct stack_frame buftail;
29 unsigned long err;
> 30 unsigned long __user *user_frame_tail = (unsigned long *)(fp - sizeof(struct stack_frame));
31
32 /* Also check accessibility of one struct frame_tail beyond */
33 if (!access_ok(user_frame_tail, sizeof(buftail)))
34 return 0;
35
36 pagefault_disable();
37 err = __copy_from_user_inatomic(&buftail, user_frame_tail, sizeof(buftail));
38 pagefault_enable();
39
40 if (err || (unsigned long)user_frame_tail >= buftail.fp)
41 return 0;
42
43 perf_callchain_store(entry, buftail.ra);
44
45 return buftail.fp;
46 }
47
--
0-DAY CI Kernel Test Service
https://01.org/lkp
On 2022/8/16 16:18, Huacai Chen wrote:
> Hi, Xuerui,
>
> On Tue, Aug 16, 2022 at 1:46 PM WANG Xuerui <[email protected]> wrote:
>> On 2022/8/15 20:47, Huacai Chen wrote:
>>> Signed-off-by: Huacai Chen <[email protected]>
>>> ---
>>> arch/loongarch/Kconfig | 2 +
>>> arch/loongarch/include/uapi/asm/perf_regs.h | 40 +
>>> arch/loongarch/kernel/Makefile | 2 +
>>> arch/loongarch/kernel/perf_event.c | 909 ++++++++++++++++++++
>>> arch/loongarch/kernel/perf_regs.c | 50 ++
>>> 5 files changed, 1003 insertions(+)
>>> create mode 100644 arch/loongarch/include/uapi/asm/perf_regs.h
>>> create mode 100644 arch/loongarch/kernel/perf_event.c
>>> create mode 100644 arch/loongarch/kernel/perf_regs.c
>> The code seems mostly ripped from arch/mips/kernel/perf_event_mipsxx.c.
>> I reviewed about half of the code then suddenly realized I might be
>> looking at MIPS code, given some of the English strings there seemed way
>> too "natural"...
>>
>> But unfortunately, at least for 3A5000 whose micro-architecture is
>> largely shared with the MIPS-implementing 3A4000, it seems inevitable to
>> involve some of the more MIPS-looking logic. The 1st-generation LA
>> privileged architecture is way too much MIPS-like after all, so if we
>> want any support for the 3A5000 we'd have to include this.
>>
>>> diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
>>> index 24665808cf3d..9478f9646fa5 100644
>>> --- a/arch/loongarch/Kconfig
>>> +++ b/arch/loongarch/Kconfig
>>> @@ -93,6 +93,8 @@ config LOONGARCH
>>> select HAVE_NMI
>>> select HAVE_PCI
>>> select HAVE_PERF_EVENTS
>>> + select HAVE_PERF_REGS
>>> + select HAVE_PERF_USER_STACK_DUMP
>>> select HAVE_REGS_AND_STACK_ACCESS_API
>>> select HAVE_RSEQ
>>> select HAVE_SETUP_PER_CPU_AREA if NUMA
>>> diff --git a/arch/loongarch/include/uapi/asm/perf_regs.h b/arch/loongarch/include/uapi/asm/perf_regs.h
>>> new file mode 100644
>>> index 000000000000..9943d418e01d
>>> --- /dev/null
>>> +++ b/arch/loongarch/include/uapi/asm/perf_regs.h
>>> @@ -0,0 +1,40 @@
>>> +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
>>> +#ifndef _ASM_LOONGARCH_PERF_REGS_H
>>> +#define _ASM_LOONGARCH_PERF_REGS_H
>>> +
>>> +enum perf_event_loongarch_regs {
>>> + PERF_REG_LOONGARCH_PC,
>>> + PERF_REG_LOONGARCH_R1,
>>> + PERF_REG_LOONGARCH_R2,
>>> + PERF_REG_LOONGARCH_R3,
>>> + PERF_REG_LOONGARCH_R4,
>>> + PERF_REG_LOONGARCH_R5,
>>> + PERF_REG_LOONGARCH_R6,
>>> + PERF_REG_LOONGARCH_R7,
>>> + PERF_REG_LOONGARCH_R8,
>>> + PERF_REG_LOONGARCH_R9,
>>> + PERF_REG_LOONGARCH_R10,
>>> + PERF_REG_LOONGARCH_R11,
>>> + PERF_REG_LOONGARCH_R12,
>>> + PERF_REG_LOONGARCH_R13,
>>> + PERF_REG_LOONGARCH_R14,
>>> + PERF_REG_LOONGARCH_R15,
>>> + PERF_REG_LOONGARCH_R16,
>>> + PERF_REG_LOONGARCH_R17,
>>> + PERF_REG_LOONGARCH_R18,
>>> + PERF_REG_LOONGARCH_R19,
>>> + PERF_REG_LOONGARCH_R20,
>>> + PERF_REG_LOONGARCH_R21,
>>> + PERF_REG_LOONGARCH_R22,
>>> + PERF_REG_LOONGARCH_R23,
>>> + PERF_REG_LOONGARCH_R24,
>>> + PERF_REG_LOONGARCH_R25,
>>> + PERF_REG_LOONGARCH_R26,
>>> + PERF_REG_LOONGARCH_R27,
>>> + PERF_REG_LOONGARCH_R28,
>>> + PERF_REG_LOONGARCH_R29,
>>> + PERF_REG_LOONGARCH_R30,
>>> + PERF_REG_LOONGARCH_R31,
>>> + PERF_REG_LOONGARCH_MAX = PERF_REG_LOONGARCH_R31 + 1,
>> No need for this "PERF_REG_LOONGARCH_R31 + 1" because it's what happens
>> without the assignment anyway?
> PERF_REG_LOONGARCH_MAX is used in perf_events.c
I think Xuerui wants to say "PERF_REG_LOONGARCH_MAX" is enough, and "=
PERF_REG_LOONGARCH_R31 + 1" can be removed.
Qi
>>> +};
>>> +#endif /* _ASM_LOONGARCH_PERF_REGS_H */
>>> diff --git a/arch/loongarch/kernel/Makefile b/arch/loongarch/kernel/Makefile
>>> index e5be17009fe8..a213e994db68 100644
>>> --- a/arch/loongarch/kernel/Makefile
>>> +++ b/arch/loongarch/kernel/Makefile
>>> @@ -26,4 +26,6 @@ obj-$(CONFIG_NUMA) += numa.o
>>> obj-$(CONFIG_UNWINDER_GUESS) += unwind_guess.o
>>> obj-$(CONFIG_UNWINDER_PROLOGUE) += unwind_prologue.o
>>>
>>> +obj-$(CONFIG_PERF_EVENTS) += perf_event.o perf_regs.o
>>> +
>>> CPPFLAGS_vmlinux.lds := $(KBUILD_CFLAGS)
>>> diff --git a/arch/loongarch/kernel/perf_event.c b/arch/loongarch/kernel/perf_event.c
>>> new file mode 100644
>>> index 000000000000..00cdbcebaf80
>>> --- /dev/null
>>> +++ b/arch/loongarch/kernel/perf_event.c
>>> @@ -0,0 +1,909 @@
>>> +// SPDX-License-Identifier: GPL-2.0
>>> +/*
>>> + * Linux performance counter support for LoongArch.
>> Please indicate its MIPS origin and copyright info ;-)
> OK, thanks.
>
>>> + *
>>> + * Copyright (C) 2022 Loongson Technology Corporation Limited
>>> + */
>>> +
>>> +#include <linux/cpumask.h>
>>> +#include <linux/interrupt.h>
>>> +#include <linux/smp.h>
>>> +#include <linux/kernel.h>
>>> +#include <linux/perf_event.h>
>>> +#include <linux/uaccess.h>
>>> +#include <linux/sched/task_stack.h>
>>> +
>>> +#include <asm/irq.h>
>>> +#include <asm/irq_regs.h>
>>> +#include <asm/stacktrace.h>
>>> +#include <asm/unwind.h>
>>> +
>>> +/*
>>> + * Get the return address for a single stackframe and return a pointer to the
>>> + * next frame tail.
>>> + */
>>> +static unsigned long
>>> +user_backtrace(struct perf_callchain_entry_ctx *entry, unsigned long fp)
>>> +{
>>> + struct stack_frame buftail;
>>> + unsigned long err;
>>> + unsigned long __user *user_frame_tail = (unsigned long *)(fp - sizeof(struct stack_frame));
>>> +
>>> + /* Also check accessibility of one struct frame_tail beyond */
>>> + if (!access_ok(user_frame_tail, sizeof(buftail)))
>>> + return 0;
>>> +
>>> + pagefault_disable();
>>> + err = __copy_from_user_inatomic(&buftail, user_frame_tail, sizeof(buftail));
>>> + pagefault_enable();
>>> +
>>> + if (err || (unsigned long)user_frame_tail >= buftail.fp)
>>> + return 0;
>>> +
>>> + perf_callchain_store(entry, buftail.ra);
>>> +
>>> + return buftail.fp;
>>> +}
>>> +
>>> +void perf_callchain_user(struct perf_callchain_entry_ctx *entry,
>>> + struct pt_regs *regs)
>>> +{
>>> + unsigned long fp;
>>> +
>>> + if (perf_guest_state()) {
>>> + /* We don't support guest os callchain now */
>>> + return;
>>> + }
>>> +
>>> + perf_callchain_store(entry, regs->csr_era);
>>> +
>>> + fp = regs->regs[22];
>>> +
>>> + while (entry->nr < entry->max_stack && fp && !((unsigned long)fp & 0xf))
>>> + fp = user_backtrace(entry, fp);
>>> +}
>>> +
>>> +void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry,
>>> + struct pt_regs *regs)
>>> +{
>>> + struct unwind_state state;
>>> + unsigned long addr;
>>> +
>>> + for (unwind_start(&state, current, regs);
>>> + !unwind_done(&state); unwind_next_frame(&state)) {
>>> + addr = unwind_get_return_address(&state);
>>> + if (!addr || perf_callchain_store(entry, addr))
>>> + return;
>>> + }
>>> +}
>>> +
>>> +#define LOONGARCH_MAX_HWEVENTS 4
>>> +
>>> +struct cpu_hw_events {
>>> + /* Array of events on this cpu. */
>>> + struct perf_event *events[LOONGARCH_MAX_HWEVENTS];
>>> +
>>> + /*
>>> + * Set the bit (indexed by the counter number) when the counter
>>> + * is used for an event.
>>> + */
>>> + unsigned long used_mask[BITS_TO_LONGS(LOONGARCH_MAX_HWEVENTS)];
>>> +
>>> + /*
>>> + * Software copy of the control register for each performance counter.
>>> + * LoongArch CPUs vary in performance counters. They use this differently,
>>> + * and even may not use it.
>> I can't easily make sense of the paragraph. "Software copy" could mean
>> "Saved copy", but how do "use differently" and "even may not use it"
>> mean? For the latter I can't deduce if it's originally "some even may
>> not exist" in someone's head, and for the former I can't imagine what's
>> the possible cases and why we would care.
>>
>> Maybe explain a little bit more?
> I think we should remove those useless lines.
>
>>> + */
>>> + unsigned int saved_ctrl[LOONGARCH_MAX_HWEVENTS];
>>> +};
>>> +static DEFINE_PER_CPU(struct cpu_hw_events, cpu_hw_events) = {
>>> + .saved_ctrl = {0},
>>> +};
>>> +
>>> +/* The description of LoongArch performance events. */
>>> +struct loongarch_perf_event {
>>> + unsigned int event_id;
>>> +};
>>> +
>>> +static struct loongarch_perf_event raw_event;
>>> +static DEFINE_MUTEX(raw_event_mutex);
>>> +
>>> +#define C(x) PERF_COUNT_HW_CACHE_##x
>>> +#define HW_OP_UNSUPPORTED 0xffffffff
>>> +#define CACHE_OP_UNSUPPORTED 0xffffffff
>>> +
>>> +#define PERF_MAP_ALL_UNSUPPORTED \
>>> + [0 ... PERF_COUNT_HW_MAX - 1] = {HW_OP_UNSUPPORTED}
>>> +
>>> +#define PERF_CACHE_MAP_ALL_UNSUPPORTED \
>>> +[0 ... C(MAX) - 1] = { \
>>> + [0 ... C(OP_MAX) - 1] = { \
>>> + [0 ... C(RESULT_MAX) - 1] = {CACHE_OP_UNSUPPORTED}, \
>>> + }, \
>>> +}
>>> +
>>> +struct loongarch_pmu {
>>> + u64 max_period;
>>> + u64 valid_count;
>>> + u64 overflow;
>>> + const char *name;
>>> + u64 (*read_counter)(unsigned int idx);
>>> + void (*write_counter)(unsigned int idx, u64 val);
>>> + const struct loongarch_perf_event *(*map_raw_event)(u64 config);
>>> + const struct loongarch_perf_event (*general_event_map)[PERF_COUNT_HW_MAX];
>>> + const struct loongarch_perf_event (*cache_event_map)
>>> + [PERF_COUNT_HW_CACHE_MAX]
>>> + [PERF_COUNT_HW_CACHE_OP_MAX]
>>> + [PERF_COUNT_HW_CACHE_RESULT_MAX];
>> Apparently general_event_map and cache_event_map are not function
>> pointers? So the parens around the field name should be removed.
> They are not function pointers, but "array pointers", but we shouldn't
> change them to "array to pointers"..
>
>>> + unsigned int num_counters;
>>> +};
>>> +
>>> +static struct loongarch_pmu loongarch_pmu;
>>> +
>>> +#define M_PERFCTL_EVENT(event) (event & CSR_PERFCTRL_EVENT)
>>> +
>>> +#define M_PERFCTL_COUNT_EVENT_WHENEVER (CSR_PERFCTRL_PLV0 | \
>>> + CSR_PERFCTRL_PLV1 | \
>>> + CSR_PERFCTRL_PLV2 | \
>>> + CSR_PERFCTRL_PLV3 | \
>>> + CSR_PERFCTRL_IE)
>>> +
>>> +#define M_PERFCTL_CONFIG_MASK 0x1f0000
>>> +
>>> +#define CNTR_BIT_MASK(n) (((n) == 64) ? ~0ULL : ((1ULL<<(n))-1))
>> Isn't this just GENMASK(n - 1, 0)?
> Yes, you are right.
>
>>> +
>>> +static void resume_local_counters(void);
>>> +static void pause_local_counters(void);
>>> +
>>> +static u64 loongarch_pmu_read_counter(unsigned int idx)
>>> +{
>>> + u64 val = -1;
>>> +
>>> + switch (idx) {
>>> + case 0:
>>> + val = read_csr_perfcntr0();
>>> + break;
>>> + case 1:
>>> + val = read_csr_perfcntr1();
>>> + break;
>>> + case 2:
>>> + val = read_csr_perfcntr2();
>>> + break;
>>> + case 3:
>>> + val = read_csr_perfcntr3();
>>> + break;
>>> + default:
>>> + WARN_ONCE(1, "Invalid performance counter number (%d)\n", idx);
>>> + return 0;
>>> + }
>>> +
>>> + return val;
>>> +}
>>> +
>>> +static void loongarch_pmu_write_counter(unsigned int idx, u64 val)
>>> +{
>>> + switch (idx) {
>>> + case 0:
>>> + write_csr_perfcntr0(val);
>>> + return;
>>> + case 1:
>>> + write_csr_perfcntr1(val);
>>> + return;
>>> + case 2:
>>> + write_csr_perfcntr2(val);
>>> + return;
>>> + case 3:
>>> + write_csr_perfcntr3(val);
>>> + return;
>> Want a default branch for this function, similar to the read case?
> Yes, that is needed.
>
>>> + }
>>> +}
>>> +
>>> +static unsigned int loongarch_pmu_read_control(unsigned int idx)
>>> +{
>>> + unsigned int val = -1;
>>> +
>>> + switch (idx) {
>>> + case 0:
>>> + val = read_csr_perfctrl0();
>>> + break;
>>> + case 1:
>>> + val = read_csr_perfctrl1();
>>> + break;
>>> + case 2:
>>> + val = read_csr_perfctrl2();
>>> + break;
>>> + case 3:
>>> + val = read_csr_perfctrl3();
>>> + break;
>>> + default:
>>> + WARN_ONCE(1, "Invalid performance counter number (%d)\n", idx);
>>> + return 0;
>>> + }
>>> +
>>> + return val;
>>> +}
>>> +
>>> +static void loongarch_pmu_write_control(unsigned int idx, unsigned int val)
>>> +{
>>> + switch (idx) {
>>> + case 0:
>>> + write_csr_perfctrl0(val);
>>> + return;
>>> + case 1:
>>> + write_csr_perfctrl1(val);
>>> + return;
>>> + case 2:
>>> + write_csr_perfctrl2(val);
>>> + return;
>>> + case 3:
>>> + write_csr_perfctrl3(val);
>>> + return;
>> Similarly here.
>>
>>> + }
>>> +}
>>> +
>>> +static int loongarch_pmu_alloc_counter(struct cpu_hw_events *cpuc,
>>> + struct hw_perf_event *hwc)
>>> +{
>>> + int i;
>>> +
>>> + for (i = loongarch_pmu.num_counters - 1; i >= 0; i--) {
>>> + if (!test_and_set_bit(i, cpuc->used_mask))
>>> + return i;
>>> + }
>>> +
>>> + return -EAGAIN;
>>> +}
>>> +
>>> +static void loongarch_pmu_enable_event(struct hw_perf_event *evt, int idx)
>>> +{
>>> + struct perf_event *event = container_of(evt, struct perf_event, hw);
>>> + struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
>>> + unsigned int cpu;
>>> +
>>> + WARN_ON(idx < 0 || idx >= loongarch_pmu.num_counters);
>>> +
>>> + cpuc->saved_ctrl[idx] = M_PERFCTL_EVENT(evt->event_base & 0xff) |
>>> + (evt->config_base & M_PERFCTL_CONFIG_MASK) |
>>> + /* Make sure interrupt enabled. */
>>> + CSR_PERFCTRL_IE;
>>> +
>>> + cpu = (event->cpu >= 0) ? event->cpu : smp_processor_id();
>>> +
>>> + pr_debug("Enabling perf counter for CPU%d\n", cpu);
>>> + /*
>>> + * We do not actually let the counter run. Leave it until start().
>>> + */
>>> +}
>>> +
>>> +static void loongarch_pmu_disable_event(int idx)
>>> +{
>>> + struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
>>> + unsigned long flags;
>>> +
>>> + WARN_ON(idx < 0 || idx >= loongarch_pmu.num_counters);
>>> +
>>> + local_irq_save(flags);
>>> + cpuc->saved_ctrl[idx] = loongarch_pmu_read_control(idx) &
>>> + ~M_PERFCTL_COUNT_EVENT_WHENEVER;
>>> + loongarch_pmu_write_control(idx, cpuc->saved_ctrl[idx]);
>>> + local_irq_restore(flags);
>>> +}
>>> +
>>> +static int loongarch_pmu_event_set_period(struct perf_event *event,
>>> + struct hw_perf_event *hwc,
>>> + int idx)
>>> +{
>>> + u64 left = local64_read(&hwc->period_left);
>>> + u64 period = hwc->sample_period;
>>> + int ret = 0;
>>> +
>>> + if (unlikely((left + period) & (1ULL << 63))) {
>>> + /* left underflowed by more than period. */
>>> + left = period;
>>> + local64_set(&hwc->period_left, left);
>>> + hwc->last_period = period;
>>> + ret = 1;
>>> + } else if (unlikely((left + period) <= period)) {
>>> + /* left underflowed by less than period. */
>>> + left += period;
>>> + local64_set(&hwc->period_left, left);
>>> + hwc->last_period = period;
>>> + ret = 1;
>>> + }
>>> +
>>> + if (left > loongarch_pmu.max_period) {
>>> + left = loongarch_pmu.max_period;
>>> + local64_set(&hwc->period_left, left);
>>> + }
>>> +
>>> + local64_set(&hwc->prev_count, loongarch_pmu.overflow - left);
>>> +
>>> + loongarch_pmu.write_counter(idx, loongarch_pmu.overflow - left);
>>> +
>>> + perf_event_update_userpage(event);
>>> +
>>> + return ret;
>>> +}
>>> +
>>> +static void loongarch_pmu_event_update(struct perf_event *event,
>>> + struct hw_perf_event *hwc,
>>> + int idx)
>>> +{
>>> + u64 delta;
>>> + u64 prev_raw_count, new_raw_count;
>>> +
>>> +again:
>>> + prev_raw_count = local64_read(&hwc->prev_count);
>>> + new_raw_count = loongarch_pmu.read_counter(idx);
>>> +
>>> + if (local64_cmpxchg(&hwc->prev_count, prev_raw_count,
>>> + new_raw_count) != prev_raw_count)
>>> + goto again;
>>> +
>>> + delta = new_raw_count - prev_raw_count;
>>> +
>>> + local64_add(delta, &event->count);
>>> + local64_sub(delta, &hwc->period_left);
>>> +}
>>> +
>>> +static void loongarch_pmu_start(struct perf_event *event, int flags)
>>> +{
>>> + struct hw_perf_event *hwc = &event->hw;
>>> +
>>> + if (flags & PERF_EF_RELOAD)
>>> + WARN_ON_ONCE(!(hwc->state & PERF_HES_UPTODATE));
>>> +
>>> + hwc->state = 0;
>>> +
>>> + /* Set the period for the event. */
>>> + loongarch_pmu_event_set_period(event, hwc, hwc->idx);
>>> +
>>> + /* Enable the event. */
>>> + loongarch_pmu_enable_event(hwc, hwc->idx);
>>> +}
>>> +
>>> +static void loongarch_pmu_stop(struct perf_event *event, int flags)
>>> +{
>>> + struct hw_perf_event *hwc = &event->hw;
>>> +
>>> + if (!(hwc->state & PERF_HES_STOPPED)) {
>>> + /* We are working on a local event. */
>>> + loongarch_pmu_disable_event(hwc->idx);
>>> + barrier();
>>> + loongarch_pmu_event_update(event, hwc, hwc->idx);
>>> + hwc->state |= PERF_HES_STOPPED | PERF_HES_UPTODATE;
>>> + }
>>> +}
>>> +
>>> +static int loongarch_pmu_add(struct perf_event *event, int flags)
>>> +{
>>> + struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
>>> + struct hw_perf_event *hwc = &event->hw;
>>> + int idx;
>>> + int err = 0;
>>> +
>>> + perf_pmu_disable(event->pmu);
>>> +
>>> + /* To look for a free counter for this event. */
>>> + idx = loongarch_pmu_alloc_counter(cpuc, hwc);
>>> + if (idx < 0) {
>>> + err = idx;
>>> + goto out;
>>> + }
>>> +
>>> + /*
>>> + * If there is an event in the counter we are going to use then
>>> + * make sure it is disabled.
>>> + */
>>> + event->hw.idx = idx;
>>> + loongarch_pmu_disable_event(idx);
>>> + cpuc->events[idx] = event;
>>> +
>>> + hwc->state = PERF_HES_STOPPED | PERF_HES_UPTODATE;
>>> + if (flags & PERF_EF_START)
>>> + loongarch_pmu_start(event, PERF_EF_RELOAD);
>>> +
>>> + /* Propagate our changes to the userspace mapping. */
>>> + perf_event_update_userpage(event);
>>> +
>>> +out:
>>> + perf_pmu_enable(event->pmu);
>>> + return err;
>>> +}
>>> +
>>> +static void loongarch_pmu_del(struct perf_event *event, int flags)
>>> +{
>>> + struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
>>> + struct hw_perf_event *hwc = &event->hw;
>>> + int idx = hwc->idx;
>>> +
>>> + WARN_ON(idx < 0 || idx >= loongarch_pmu.num_counters);
>>> +
>>> + loongarch_pmu_stop(event, PERF_EF_UPDATE);
>>> + cpuc->events[idx] = NULL;
>>> + clear_bit(idx, cpuc->used_mask);
>>> +
>>> + perf_event_update_userpage(event);
>>> +}
>>> +
>>> +static void loongarch_pmu_read(struct perf_event *event)
>>> +{
>>> + struct hw_perf_event *hwc = &event->hw;
>>> +
>>> + /* Don't read disabled counters! */
>>> + if (hwc->idx < 0)
>>> + return;
>>> +
>>> + loongarch_pmu_event_update(event, hwc, hwc->idx);
>>> +}
>>> +
>>> +static void loongarch_pmu_enable(struct pmu *pmu)
>>> +{
>>> + resume_local_counters();
>>> +}
>>> +
>>> +static void loongarch_pmu_disable(struct pmu *pmu)
>>> +{
>>> + pause_local_counters();
>>> +}
>>> +
>>> +static atomic_t active_events = ATOMIC_INIT(0);
>>> +static DEFINE_MUTEX(pmu_reserve_mutex);
>>> +
>>> +static void reset_counters(void *arg);
>>> +static int __hw_perf_event_init(struct perf_event *event);
>>> +
>>> +static void hw_perf_event_destroy(struct perf_event *event)
>>> +{
>>> + if (atomic_dec_and_mutex_lock(&active_events,
>>> + &pmu_reserve_mutex)) {
>>> + /*
>>> + * We must not call the destroy function with interrupts
>>> + * disabled.
>>> + */
>>> + on_each_cpu(reset_counters,
>>> + (void *)(long)loongarch_pmu.num_counters, 1);
>>> + mutex_unlock(&pmu_reserve_mutex);
>>> + }
>>> +}
>>> +
>>> +/* This is needed by specific irq handlers in perf_event_*.c */
>>> +static void handle_associated_event(struct cpu_hw_events *cpuc,
>>> + int idx, struct perf_sample_data *data,
>>> + struct pt_regs *regs)
>>> +{
>>> + struct perf_event *event = cpuc->events[idx];
>>> + struct hw_perf_event *hwc = &event->hw;
>>> +
>>> + loongarch_pmu_event_update(event, hwc, idx);
>>> + data->period = event->hw.last_period;
>>> + if (!loongarch_pmu_event_set_period(event, hwc, idx))
>>> + return;
>>> +
>>> + if (perf_event_overflow(event, data, regs))
>>> + loongarch_pmu_disable_event(idx);
>>> +}
>>> +
>>> +static irqreturn_t pmu_handle_irq(int irq, void *dev)
>>> +{
>>> + int handled = IRQ_NONE;
>>> + unsigned int counters = loongarch_pmu.num_counters;
>>> + u64 counter;
>>> + struct pt_regs *regs;
>>> + struct perf_sample_data data;
>>> + struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
>>> +
>>> + /*
>>> + * First we pause the local counters, so that when we are locked
>>> + * here, the counters are all paused. When it gets locked due to
>>> + * perf_disable(), the timer interrupt handler will be delayed.
>>> + *
>>> + * See also loongarch_pmu_start().
>>> + */
>>> + pause_local_counters();
>>> +
>>> + regs = get_irq_regs();
>>> +
>>> + perf_sample_data_init(&data, 0, 0);
>>> +
>>> + switch (counters) {
>>> +#define HANDLE_COUNTER(n) \
>>> + case n + 1: \
>>> + if (test_bit(n, cpuc->used_mask)) { \
>>> + counter = loongarch_pmu.read_counter(n); \
>>> + if (counter & loongarch_pmu.overflow) { \
>>> + handle_associated_event(cpuc, n, &data, regs); \
>>> + handled = IRQ_HANDLED; \
>>> + } \
>>> + }
>>> + HANDLE_COUNTER(3)
>>> + fallthrough;
>>> + HANDLE_COUNTER(2)
>>> + fallthrough;
>>> + HANDLE_COUNTER(1)
>>> + fallthrough;
>>> + HANDLE_COUNTER(0)
>>> + }
>>> +
>>> + resume_local_counters();
>>> +
>>> + /*
>>> + * Do all the work for the pending perf events. We can do this
>>> + * in here because the performance counter interrupt is a regular
>>> + * interrupt, not NMI.
>>> + */
>>> + if (handled == IRQ_HANDLED)
>>> + irq_work_run();
>>> +
>>> + return handled;
>>> +}
>>> +
>>> +static int get_pmc_irq(void)
>>> +{
>>> + struct irq_domain *d = irq_find_matching_fwnode(cpuintc_handle, DOMAIN_BUS_ANY);
>>> +
>>> + if (d)
>>> + return irq_create_mapping(d, EXCCODE_PMC - EXCCODE_INT_START);
>>> +
>>> + return -EINVAL;
>>> +}
>>> +
>>> +static int loongarch_pmu_event_init(struct perf_event *event)
>>> +{
>>> + int r, irq;
>>> + unsigned long flags;
>>> +
>>> + /* does not support taken branch sampling */
>>> + if (has_branch_stack(event))
>>> + return -EOPNOTSUPP;
>>> +
>>> + switch (event->attr.type) {
>>> + case PERF_TYPE_RAW:
>>> + case PERF_TYPE_HARDWARE:
>>> + case PERF_TYPE_HW_CACHE:
>>> + break;
>>> +
>>> + default:
>>> + /* Init it to avoid false validate_group */
>>> + event->hw.event_base = 0xffffffff;
>>> + return -ENOENT;
>>> + }
>>> +
>>> + if (event->cpu >= 0 && !cpu_online(event->cpu))
>>> + return -ENODEV;
>>> +
>>> + irq = get_pmc_irq();
>>> + flags = IRQF_PERCPU | IRQF_NOBALANCING | IRQF_NO_THREAD | IRQF_NO_SUSPEND | IRQF_SHARED;
>>> + if (!atomic_inc_not_zero(&active_events)) {
>>> + mutex_lock(&pmu_reserve_mutex);
>>> + if (atomic_read(&active_events) == 0) {
>>> + r = request_irq(irq, pmu_handle_irq,
>>> + flags, "Perf_PMU", &loongarch_pmu);
>>> + if (r < 0) {
>>> + pr_warn("PMU IRQ request failed\n");
>>> + return -ENODEV;
>>> + }
>>> + }
>>> + atomic_inc(&active_events);
>>> + mutex_unlock(&pmu_reserve_mutex);
>>> + }
>>> +
>>> + return __hw_perf_event_init(event);
>>> +}
>>> +
>>> +static struct pmu pmu = {
>>> + .pmu_enable = loongarch_pmu_enable,
>>> + .pmu_disable = loongarch_pmu_disable,
>>> + .event_init = loongarch_pmu_event_init,
>>> + .add = loongarch_pmu_add,
>>> + .del = loongarch_pmu_del,
>>> + .start = loongarch_pmu_start,
>>> + .stop = loongarch_pmu_stop,
>>> + .read = loongarch_pmu_read,
>>> +};
>>> +
>>> +static unsigned int loongarch_pmu_perf_event_encode(const struct loongarch_perf_event *pev)
>>> +{
>>> + return (pev->event_id & 0xff);
>>> +}
>>> +
>>> +static const struct loongarch_perf_event *loongarch_pmu_map_general_event(int idx)
>>> +{
>>> + const struct loongarch_perf_event *pev;
>>> +
>>> + pev = &(*loongarch_pmu.general_event_map)[idx];
>>> +
>>> + if (pev->event_id == HW_OP_UNSUPPORTED)
>>> + return ERR_PTR(-ENOENT);
>>> +
>>> + return pev;
>>> +}
>>> +
>>> +static const struct loongarch_perf_event *loongarch_pmu_map_cache_event(u64 config)
>>> +{
>>> + unsigned int cache_type, cache_op, cache_result;
>>> + const struct loongarch_perf_event *pev;
>>> +
>>> + cache_type = (config >> 0) & 0xff;
>>> + if (cache_type >= PERF_COUNT_HW_CACHE_MAX)
>>> + return ERR_PTR(-EINVAL);
>>> +
>>> + cache_op = (config >> 8) & 0xff;
>>> + if (cache_op >= PERF_COUNT_HW_CACHE_OP_MAX)
>>> + return ERR_PTR(-EINVAL);
>>> +
>>> + cache_result = (config >> 16) & 0xff;
>>> + if (cache_result >= PERF_COUNT_HW_CACHE_RESULT_MAX)
>>> + return ERR_PTR(-EINVAL);
>>> +
>>> + pev = &((*loongarch_pmu.cache_event_map)
>>> + [cache_type]
>>> + [cache_op]
>>> + [cache_result]);
>>> +
>>> + if (pev->event_id == CACHE_OP_UNSUPPORTED)
>>> + return ERR_PTR(-ENOENT);
>>> +
>>> + return pev;
>>> +}
>>> +
>>> +static int validate_group(struct perf_event *event)
>>> +{
>>> + struct perf_event *sibling, *leader = event->group_leader;
>>> + struct cpu_hw_events fake_cpuc;
>>> +
>>> + memset(&fake_cpuc, 0, sizeof(fake_cpuc));
>>> +
>>> + if (loongarch_pmu_alloc_counter(&fake_cpuc, &leader->hw) < 0)
>>> + return -EINVAL;
>>> +
>>> + for_each_sibling_event(sibling, leader) {
>>> + if (loongarch_pmu_alloc_counter(&fake_cpuc, &sibling->hw) < 0)
>>> + return -EINVAL;
>>> + }
>>> +
>>> + if (loongarch_pmu_alloc_counter(&fake_cpuc, &event->hw) < 0)
>>> + return -EINVAL;
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +static void reset_counters(void *arg)
>>> +{
>>> + int counters = (int)(long)arg;
>>> +
>>> + switch (counters) {
>>> + case 4:
>>> + loongarch_pmu_write_control(3, 0);
>>> + loongarch_pmu.write_counter(3, 0);
>>> + fallthrough;
>>> + case 3:
>>> + loongarch_pmu_write_control(2, 0);
>>> + loongarch_pmu.write_counter(2, 0);
>>> + fallthrough;
>>> + case 2:
>>> + loongarch_pmu_write_control(1, 0);
>>> + loongarch_pmu.write_counter(1, 0);
>>> + fallthrough;
>>> + case 1:
>>> + loongarch_pmu_write_control(0, 0);
>>> + loongarch_pmu.write_counter(0, 0);
>>> + }
>>> +}
>>> +
>>> +static const struct loongarch_perf_event loongson_new_event_map[PERF_COUNT_HW_MAX] = {
>>> + PERF_MAP_ALL_UNSUPPORTED,
>>> + [PERF_COUNT_HW_CPU_CYCLES] = { 0x00 },
>>> + [PERF_COUNT_HW_INSTRUCTIONS] = { 0x01 },
>>> + [PERF_COUNT_HW_CACHE_REFERENCES] = { 0x08 },
>>> + [PERF_COUNT_HW_CACHE_MISSES] = { 0x09 },
>>> + [PERF_COUNT_HW_BRANCH_INSTRUCTIONS] = { 0x02 },
>>> + [PERF_COUNT_HW_BRANCH_MISSES] = { 0x03 },
>>> +};
>>> +
>>> +static const struct loongarch_perf_event loongson_new_cache_map
>>> + [PERF_COUNT_HW_CACHE_MAX]
>>> + [PERF_COUNT_HW_CACHE_OP_MAX]
>>> + [PERF_COUNT_HW_CACHE_RESULT_MAX] = {
>>> +PERF_CACHE_MAP_ALL_UNSUPPORTED,
>>> +[C(L1D)] = {
>>> + /*
>>> + * Like some other architectures (e.g. ARM), the performance
>>> + * counters don't differentiate between read and write
>>> + * accesses/misses, so this isn't strictly correct, but it's the
>>> + * best we can do. Writes and reads get combined.
>>> + */
>>> + [C(OP_READ)] = {
>>> + [C(RESULT_ACCESS)] = { 0x8 },
>>> + [C(RESULT_MISS)] = { 0x9 },
>>> + },
>>> + [C(OP_WRITE)] = {
>>> + [C(RESULT_ACCESS)] = { 0x8 },
>>> + [C(RESULT_MISS)] = { 0x9 },
>>> + },
>>> + [C(OP_PREFETCH)] = {
>>> + [C(RESULT_ACCESS)] = { 0xaa },
>>> + [C(RESULT_MISS)] = { 0xa9 },
>>> + },
>>> +},
>>> +[C(L1I)] = {
>>> + [C(OP_READ)] = {
>>> + [C(RESULT_ACCESS)] = { 0x6 },
>>> + [C(RESULT_MISS)] = { 0x7 },
>>> + },
>>> +},
>>> +[C(LL)] = {
>>> + [C(OP_READ)] = {
>>> + [C(RESULT_ACCESS)] = { 0xc },
>>> + [C(RESULT_MISS)] = { 0xd },
>>> + },
>>> + [C(OP_WRITE)] = {
>>> + [C(RESULT_ACCESS)] = { 0xc },
>>> + [C(RESULT_MISS)] = { 0xd },
>>> + },
>>> +},
>>> +[C(ITLB)] = {
>>> + [C(OP_READ)] = {
>>> + [C(RESULT_MISS)] = { 0x3b },
>>> + },
>>> +},
>>> +[C(DTLB)] = {
>>> + [C(OP_READ)] = {
>>> + [C(RESULT_ACCESS)] = { 0x4 },
>>> + [C(RESULT_MISS)] = { 0x3c },
>>> + },
>>> + [C(OP_WRITE)] = {
>>> + [C(RESULT_ACCESS)] = { 0x4 },
>>> + [C(RESULT_MISS)] = { 0x3c },
>>> + },
>>> +},
>>> +[C(BPU)] = {
>>> + /* Using the same code for *HW_BRANCH* */
>>> + [C(OP_READ)] = {
>>> + [C(RESULT_ACCESS)] = { 0x02 },
>>> + [C(RESULT_MISS)] = { 0x03 },
>>> + },
>>> +},
>>> +};
>>> +
>>> +static int __hw_perf_event_init(struct perf_event *event)
>>> +{
>>> + struct perf_event_attr *attr = &event->attr;
>>> + struct hw_perf_event *hwc = &event->hw;
>>> + const struct loongarch_perf_event *pev;
>>> + int err;
>>> +
>>> + /* Returning LoongArch event descriptor for generic perf event. */
>>> + if (PERF_TYPE_HARDWARE == event->attr.type) {
>>> + if (event->attr.config >= PERF_COUNT_HW_MAX)
>>> + return -EINVAL;
>>> + pev = loongarch_pmu_map_general_event(event->attr.config);
>>> + } else if (PERF_TYPE_HW_CACHE == event->attr.type) {
>>> + pev = loongarch_pmu_map_cache_event(event->attr.config);
>>> + } else if (PERF_TYPE_RAW == event->attr.type) {
>>> + /* We are working on the global raw event. */
>>> + mutex_lock(&raw_event_mutex);
>>> + pev = loongarch_pmu.map_raw_event(event->attr.config);
>>> + } else {
>>> + /* The event type is not (yet) supported. */
>>> + return -EOPNOTSUPP;
>>> + }
>>> +
>>> + if (IS_ERR(pev)) {
>>> + if (PERF_TYPE_RAW == event->attr.type)
>>> + mutex_unlock(&raw_event_mutex);
>>> + return PTR_ERR(pev);
>>> + }
>>> +
>>> + /*
>>> + * We allow max flexibility on how each individual counter shared
>>> + * by the single CPU operates (the mode exclusion and the range).
>>> + */
>>> + hwc->config_base = CSR_PERFCTRL_IE;
>>> +
>>> + hwc->event_base = loongarch_pmu_perf_event_encode(pev);
>>> + if (PERF_TYPE_RAW == event->attr.type)
>>> + mutex_unlock(&raw_event_mutex);
>>> +
>>> + if (!attr->exclude_user) {
>>> + hwc->config_base |= CSR_PERFCTRL_PLV3;
>>> + hwc->config_base |= CSR_PERFCTRL_PLV2;
>>> + }
>>> + if (!attr->exclude_kernel) {
>>> + hwc->config_base |= CSR_PERFCTRL_PLV0;
>>> + }
>>> + if (!attr->exclude_hv) {
>>> + hwc->config_base |= CSR_PERFCTRL_PLV1;
>>> + }
>>> +
>>> + hwc->config_base &= M_PERFCTL_CONFIG_MASK;
>>> + /*
>>> + * The event can belong to another cpu. We do not assign a local
>>> + * counter for it for now.
>>> + */
>>> + hwc->idx = -1;
>>> + hwc->config = 0;
>>> +
>>> + if (!hwc->sample_period) {
>>> + hwc->sample_period = loongarch_pmu.max_period;
>>> + hwc->last_period = hwc->sample_period;
>>> + local64_set(&hwc->period_left, hwc->sample_period);
>>> + }
>>> +
>>> + err = 0;
>>> + if (event->group_leader != event)
>>> + err = validate_group(event);
>>> +
>>> + event->destroy = hw_perf_event_destroy;
>>> +
>>> + if (err)
>>> + event->destroy(event);
>>> +
>>> + return err;
>>> +}
>>> +
>>> +static void pause_local_counters(void)
>>> +{
>>> + struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
>>> + int ctr = loongarch_pmu.num_counters;
>>> + unsigned long flags;
>>> +
>>> + local_irq_save(flags);
>>> + do {
>>> + ctr--;
>>> + cpuc->saved_ctrl[ctr] = loongarch_pmu_read_control(ctr);
>>> + loongarch_pmu_write_control(ctr, cpuc->saved_ctrl[ctr] &
>>> + ~M_PERFCTL_COUNT_EVENT_WHENEVER);
>>> + } while (ctr > 0);
>>> + local_irq_restore(flags);
>>> +}
>>> +
>>> +static void resume_local_counters(void)
>>> +{
>>> + struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
>>> + int ctr = loongarch_pmu.num_counters;
>>> +
>>> + do {
>>> + ctr--;
>>> + loongarch_pmu_write_control(ctr, cpuc->saved_ctrl[ctr]);
>>> + } while (ctr > 0);
>>> +}
>>> +
>>> +static const struct loongarch_perf_event *loongarch_pmu_map_raw_event(u64 config)
>>> +{
>>> + raw_event.event_id = config & 0xff;
>>> +
>>> + return &raw_event;
>>> +}
>>> +
>>> +static int __init
>>> +init_hw_perf_events(void)
>>> +{
>>> + int counters = 4;
>>> +
>>> + if (!cpu_has_pmp)
>>> + return -ENODEV;
>>> +
>>> + pr_info("Performance counters: ");
>>> +
>>> + loongarch_pmu.num_counters = counters;
>>> + loongarch_pmu.max_period = (1ULL << 63) - 1;
>>> + loongarch_pmu.valid_count = (1ULL << 63) - 1;
>>> + loongarch_pmu.overflow = 1ULL << 63;
>>> + loongarch_pmu.name = "loongarch/loongson64";
>>> + loongarch_pmu.read_counter = loongarch_pmu_read_counter;
>>> + loongarch_pmu.write_counter = loongarch_pmu_write_counter;
>>> + loongarch_pmu.map_raw_event = loongarch_pmu_map_raw_event;
>>> + loongarch_pmu.general_event_map = &loongson_new_event_map;
>>> + loongarch_pmu.cache_event_map = &loongson_new_cache_map;
>>> +
>>> + on_each_cpu(reset_counters, (void *)(long)counters, 1);
>>> +
>>> + pr_cont("%s PMU enabled, %d %d-bit counters available to each "
>>> + "CPU.\n", loongarch_pmu.name, counters, 64);
>>> +
>>> + perf_pmu_register(&pmu, "cpu", PERF_TYPE_RAW);
>>> +
>>> + return 0;
>>> +}
>>> +early_initcall(init_hw_perf_events);
>>> diff --git a/arch/loongarch/kernel/perf_regs.c b/arch/loongarch/kernel/perf_regs.c
>>> new file mode 100644
>>> index 000000000000..a5e9768e8414
>>> --- /dev/null
>>> +++ b/arch/loongarch/kernel/perf_regs.c
>>> @@ -0,0 +1,50 @@
>>> +// SPDX-License-Identifier: GPL-2.0
>>> +/*
>>> + * Copyright (C) 2022 Loongson Technology Corporation Limited
>> And this file.
> OK, thanks.
>
> Huacai
>>> + */
>>> +
>>> +#include <linux/perf_event.h>
>>> +
>>> +#include <asm/ptrace.h>
>>> +
>>> +#ifdef CONFIG_32BIT
>>> +u64 perf_reg_abi(struct task_struct *tsk)
>>> +{
>>> + return PERF_SAMPLE_REGS_ABI_32;
>>> +}
>>> +#else /* Must be CONFIG_64BIT */
>>> +u64 perf_reg_abi(struct task_struct *tsk)
>>> +{
>>> + if (test_tsk_thread_flag(tsk, TIF_32BIT_REGS))
>>> + return PERF_SAMPLE_REGS_ABI_32;
>>> + else
>>> + return PERF_SAMPLE_REGS_ABI_64;
>>> +}
>>> +#endif /* CONFIG_32BIT */
>>> +
>>> +int perf_reg_validate(u64 mask)
>>> +{
>>> + if (!mask)
>>> + return -EINVAL;
>>> + if (mask & ~((1ull << PERF_REG_LOONGARCH_MAX) - 1))
>>> + return -EINVAL;
>>> + return 0;
>>> +}
>>> +
>>> +u64 perf_reg_value(struct pt_regs *regs, int idx)
>>> +{
>>> + if (WARN_ON_ONCE((u32)idx >= PERF_REG_LOONGARCH_MAX))
>>> + return 0;
>>> +
>>> + if ((u32)idx == PERF_REG_LOONGARCH_PC)
>>> + return regs->csr_era;
>>> +
>>> + return regs->regs[idx];
>>> +}
>>> +
>>> +void perf_get_regs_user(struct perf_regs *regs_user,
>>> + struct pt_regs *regs)
>>> +{
>>> + regs_user->regs = task_pt_regs(current);
>>> + regs_user->abi = perf_reg_abi(current);
>>> +}
>> --
>> WANG "xen0n" Xuerui
>>
>> Linux/LoongArch mailing list: https://lore.kernel.org/loongarch/
>>
On Tue, Aug 16, 2022 at 6:07 PM Qi Hu <[email protected]> wrote:
>
>
> On 2022/8/16 16:18, Huacai Chen wrote:
> > Hi, Xuerui,
> >
> > On Tue, Aug 16, 2022 at 1:46 PM WANG Xuerui <[email protected]> wrote:
> >> On 2022/8/15 20:47, Huacai Chen wrote:
> >>> Signed-off-by: Huacai Chen <[email protected]>
> >>> ---
> >>> arch/loongarch/Kconfig | 2 +
> >>> arch/loongarch/include/uapi/asm/perf_regs.h | 40 +
> >>> arch/loongarch/kernel/Makefile | 2 +
> >>> arch/loongarch/kernel/perf_event.c | 909 ++++++++++++++++++++
> >>> arch/loongarch/kernel/perf_regs.c | 50 ++
> >>> 5 files changed, 1003 insertions(+)
> >>> create mode 100644 arch/loongarch/include/uapi/asm/perf_regs.h
> >>> create mode 100644 arch/loongarch/kernel/perf_event.c
> >>> create mode 100644 arch/loongarch/kernel/perf_regs.c
> >> The code seems mostly ripped from arch/mips/kernel/perf_event_mipsxx.c.
> >> I reviewed about half of the code then suddenly realized I might be
> >> looking at MIPS code, given some of the English strings there seemed way
> >> too "natural"...
> >>
> >> But unfortunately, at least for 3A5000 whose micro-architecture is
> >> largely shared with the MIPS-implementing 3A4000, it seems inevitable to
> >> involve some of the more MIPS-looking logic. The 1st-generation LA
> >> privileged architecture is way too much MIPS-like after all, so if we
> >> want any support for the 3A5000 we'd have to include this.
> >>
> >>> diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
> >>> index 24665808cf3d..9478f9646fa5 100644
> >>> --- a/arch/loongarch/Kconfig
> >>> +++ b/arch/loongarch/Kconfig
> >>> @@ -93,6 +93,8 @@ config LOONGARCH
> >>> select HAVE_NMI
> >>> select HAVE_PCI
> >>> select HAVE_PERF_EVENTS
> >>> + select HAVE_PERF_REGS
> >>> + select HAVE_PERF_USER_STACK_DUMP
> >>> select HAVE_REGS_AND_STACK_ACCESS_API
> >>> select HAVE_RSEQ
> >>> select HAVE_SETUP_PER_CPU_AREA if NUMA
> >>> diff --git a/arch/loongarch/include/uapi/asm/perf_regs.h b/arch/loongarch/include/uapi/asm/perf_regs.h
> >>> new file mode 100644
> >>> index 000000000000..9943d418e01d
> >>> --- /dev/null
> >>> +++ b/arch/loongarch/include/uapi/asm/perf_regs.h
> >>> @@ -0,0 +1,40 @@
> >>> +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
> >>> +#ifndef _ASM_LOONGARCH_PERF_REGS_H
> >>> +#define _ASM_LOONGARCH_PERF_REGS_H
> >>> +
> >>> +enum perf_event_loongarch_regs {
> >>> + PERF_REG_LOONGARCH_PC,
> >>> + PERF_REG_LOONGARCH_R1,
> >>> + PERF_REG_LOONGARCH_R2,
> >>> + PERF_REG_LOONGARCH_R3,
> >>> + PERF_REG_LOONGARCH_R4,
> >>> + PERF_REG_LOONGARCH_R5,
> >>> + PERF_REG_LOONGARCH_R6,
> >>> + PERF_REG_LOONGARCH_R7,
> >>> + PERF_REG_LOONGARCH_R8,
> >>> + PERF_REG_LOONGARCH_R9,
> >>> + PERF_REG_LOONGARCH_R10,
> >>> + PERF_REG_LOONGARCH_R11,
> >>> + PERF_REG_LOONGARCH_R12,
> >>> + PERF_REG_LOONGARCH_R13,
> >>> + PERF_REG_LOONGARCH_R14,
> >>> + PERF_REG_LOONGARCH_R15,
> >>> + PERF_REG_LOONGARCH_R16,
> >>> + PERF_REG_LOONGARCH_R17,
> >>> + PERF_REG_LOONGARCH_R18,
> >>> + PERF_REG_LOONGARCH_R19,
> >>> + PERF_REG_LOONGARCH_R20,
> >>> + PERF_REG_LOONGARCH_R21,
> >>> + PERF_REG_LOONGARCH_R22,
> >>> + PERF_REG_LOONGARCH_R23,
> >>> + PERF_REG_LOONGARCH_R24,
> >>> + PERF_REG_LOONGARCH_R25,
> >>> + PERF_REG_LOONGARCH_R26,
> >>> + PERF_REG_LOONGARCH_R27,
> >>> + PERF_REG_LOONGARCH_R28,
> >>> + PERF_REG_LOONGARCH_R29,
> >>> + PERF_REG_LOONGARCH_R30,
> >>> + PERF_REG_LOONGARCH_R31,
> >>> + PERF_REG_LOONGARCH_MAX = PERF_REG_LOONGARCH_R31 + 1,
> >> No need for this "PERF_REG_LOONGARCH_R31 + 1" because it's what happens
> >> without the assignment anyway?
> > PERF_REG_LOONGARCH_MAX is used in perf_events.c
>
> I think Xuerui wants to say "PERF_REG_LOONGARCH_MAX" is enough, and "=
> PERF_REG_LOONGARCH_R31 + 1" can be removed.
Yes, you are right, I'm sorry.
Huacai
>
> Qi
>
> >>> +};
> >>> +#endif /* _ASM_LOONGARCH_PERF_REGS_H */
> >>> diff --git a/arch/loongarch/kernel/Makefile b/arch/loongarch/kernel/Makefile
> >>> index e5be17009fe8..a213e994db68 100644
> >>> --- a/arch/loongarch/kernel/Makefile
> >>> +++ b/arch/loongarch/kernel/Makefile
> >>> @@ -26,4 +26,6 @@ obj-$(CONFIG_NUMA) += numa.o
> >>> obj-$(CONFIG_UNWINDER_GUESS) += unwind_guess.o
> >>> obj-$(CONFIG_UNWINDER_PROLOGUE) += unwind_prologue.o
> >>>
> >>> +obj-$(CONFIG_PERF_EVENTS) += perf_event.o perf_regs.o
> >>> +
> >>> CPPFLAGS_vmlinux.lds := $(KBUILD_CFLAGS)
> >>> diff --git a/arch/loongarch/kernel/perf_event.c b/arch/loongarch/kernel/perf_event.c
> >>> new file mode 100644
> >>> index 000000000000..00cdbcebaf80
> >>> --- /dev/null
> >>> +++ b/arch/loongarch/kernel/perf_event.c
> >>> @@ -0,0 +1,909 @@
> >>> +// SPDX-License-Identifier: GPL-2.0
> >>> +/*
> >>> + * Linux performance counter support for LoongArch.
> >> Please indicate its MIPS origin and copyright info ;-)
> > OK, thanks.
> >
> >>> + *
> >>> + * Copyright (C) 2022 Loongson Technology Corporation Limited
> >>> + */
> >>> +
> >>> +#include <linux/cpumask.h>
> >>> +#include <linux/interrupt.h>
> >>> +#include <linux/smp.h>
> >>> +#include <linux/kernel.h>
> >>> +#include <linux/perf_event.h>
> >>> +#include <linux/uaccess.h>
> >>> +#include <linux/sched/task_stack.h>
> >>> +
> >>> +#include <asm/irq.h>
> >>> +#include <asm/irq_regs.h>
> >>> +#include <asm/stacktrace.h>
> >>> +#include <asm/unwind.h>
> >>> +
> >>> +/*
> >>> + * Get the return address for a single stackframe and return a pointer to the
> >>> + * next frame tail.
> >>> + */
> >>> +static unsigned long
> >>> +user_backtrace(struct perf_callchain_entry_ctx *entry, unsigned long fp)
> >>> +{
> >>> + struct stack_frame buftail;
> >>> + unsigned long err;
> >>> + unsigned long __user *user_frame_tail = (unsigned long *)(fp - sizeof(struct stack_frame));
> >>> +
> >>> + /* Also check accessibility of one struct frame_tail beyond */
> >>> + if (!access_ok(user_frame_tail, sizeof(buftail)))
> >>> + return 0;
> >>> +
> >>> + pagefault_disable();
> >>> + err = __copy_from_user_inatomic(&buftail, user_frame_tail, sizeof(buftail));
> >>> + pagefault_enable();
> >>> +
> >>> + if (err || (unsigned long)user_frame_tail >= buftail.fp)
> >>> + return 0;
> >>> +
> >>> + perf_callchain_store(entry, buftail.ra);
> >>> +
> >>> + return buftail.fp;
> >>> +}
> >>> +
> >>> +void perf_callchain_user(struct perf_callchain_entry_ctx *entry,
> >>> + struct pt_regs *regs)
> >>> +{
> >>> + unsigned long fp;
> >>> +
> >>> + if (perf_guest_state()) {
> >>> + /* We don't support guest os callchain now */
> >>> + return;
> >>> + }
> >>> +
> >>> + perf_callchain_store(entry, regs->csr_era);
> >>> +
> >>> + fp = regs->regs[22];
> >>> +
> >>> + while (entry->nr < entry->max_stack && fp && !((unsigned long)fp & 0xf))
> >>> + fp = user_backtrace(entry, fp);
> >>> +}
> >>> +
> >>> +void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry,
> >>> + struct pt_regs *regs)
> >>> +{
> >>> + struct unwind_state state;
> >>> + unsigned long addr;
> >>> +
> >>> + for (unwind_start(&state, current, regs);
> >>> + !unwind_done(&state); unwind_next_frame(&state)) {
> >>> + addr = unwind_get_return_address(&state);
> >>> + if (!addr || perf_callchain_store(entry, addr))
> >>> + return;
> >>> + }
> >>> +}
> >>> +
> >>> +#define LOONGARCH_MAX_HWEVENTS 4
> >>> +
> >>> +struct cpu_hw_events {
> >>> + /* Array of events on this cpu. */
> >>> + struct perf_event *events[LOONGARCH_MAX_HWEVENTS];
> >>> +
> >>> + /*
> >>> + * Set the bit (indexed by the counter number) when the counter
> >>> + * is used for an event.
> >>> + */
> >>> + unsigned long used_mask[BITS_TO_LONGS(LOONGARCH_MAX_HWEVENTS)];
> >>> +
> >>> + /*
> >>> + * Software copy of the control register for each performance counter.
> >>> + * LoongArch CPUs vary in performance counters. They use this differently,
> >>> + * and even may not use it.
> >> I can't easily make sense of the paragraph. "Software copy" could mean
> >> "Saved copy", but how do "use differently" and "even may not use it"
> >> mean? For the latter I can't deduce if it's originally "some even may
> >> not exist" in someone's head, and for the former I can't imagine what's
> >> the possible cases and why we would care.
> >>
> >> Maybe explain a little bit more?
> > I think we should remove those useless lines.
> >
> >>> + */
> >>> + unsigned int saved_ctrl[LOONGARCH_MAX_HWEVENTS];
> >>> +};
> >>> +static DEFINE_PER_CPU(struct cpu_hw_events, cpu_hw_events) = {
> >>> + .saved_ctrl = {0},
> >>> +};
> >>> +
> >>> +/* The description of LoongArch performance events. */
> >>> +struct loongarch_perf_event {
> >>> + unsigned int event_id;
> >>> +};
> >>> +
> >>> +static struct loongarch_perf_event raw_event;
> >>> +static DEFINE_MUTEX(raw_event_mutex);
> >>> +
> >>> +#define C(x) PERF_COUNT_HW_CACHE_##x
> >>> +#define HW_OP_UNSUPPORTED 0xffffffff
> >>> +#define CACHE_OP_UNSUPPORTED 0xffffffff
> >>> +
> >>> +#define PERF_MAP_ALL_UNSUPPORTED \
> >>> + [0 ... PERF_COUNT_HW_MAX - 1] = {HW_OP_UNSUPPORTED}
> >>> +
> >>> +#define PERF_CACHE_MAP_ALL_UNSUPPORTED \
> >>> +[0 ... C(MAX) - 1] = { \
> >>> + [0 ... C(OP_MAX) - 1] = { \
> >>> + [0 ... C(RESULT_MAX) - 1] = {CACHE_OP_UNSUPPORTED}, \
> >>> + }, \
> >>> +}
> >>> +
> >>> +struct loongarch_pmu {
> >>> + u64 max_period;
> >>> + u64 valid_count;
> >>> + u64 overflow;
> >>> + const char *name;
> >>> + u64 (*read_counter)(unsigned int idx);
> >>> + void (*write_counter)(unsigned int idx, u64 val);
> >>> + const struct loongarch_perf_event *(*map_raw_event)(u64 config);
> >>> + const struct loongarch_perf_event (*general_event_map)[PERF_COUNT_HW_MAX];
> >>> + const struct loongarch_perf_event (*cache_event_map)
> >>> + [PERF_COUNT_HW_CACHE_MAX]
> >>> + [PERF_COUNT_HW_CACHE_OP_MAX]
> >>> + [PERF_COUNT_HW_CACHE_RESULT_MAX];
> >> Apparently general_event_map and cache_event_map are not function
> >> pointers? So the parens around the field name should be removed.
> > They are not function pointers, but "array pointers", but we shouldn't
> > change them to "array to pointers"..
> >
> >>> + unsigned int num_counters;
> >>> +};
> >>> +
> >>> +static struct loongarch_pmu loongarch_pmu;
> >>> +
> >>> +#define M_PERFCTL_EVENT(event) (event & CSR_PERFCTRL_EVENT)
> >>> +
> >>> +#define M_PERFCTL_COUNT_EVENT_WHENEVER (CSR_PERFCTRL_PLV0 | \
> >>> + CSR_PERFCTRL_PLV1 | \
> >>> + CSR_PERFCTRL_PLV2 | \
> >>> + CSR_PERFCTRL_PLV3 | \
> >>> + CSR_PERFCTRL_IE)
> >>> +
> >>> +#define M_PERFCTL_CONFIG_MASK 0x1f0000
> >>> +
> >>> +#define CNTR_BIT_MASK(n) (((n) == 64) ? ~0ULL : ((1ULL<<(n))-1))
> >> Isn't this just GENMASK(n - 1, 0)?
> > Yes, you are right.
> >
> >>> +
> >>> +static void resume_local_counters(void);
> >>> +static void pause_local_counters(void);
> >>> +
> >>> +static u64 loongarch_pmu_read_counter(unsigned int idx)
> >>> +{
> >>> + u64 val = -1;
> >>> +
> >>> + switch (idx) {
> >>> + case 0:
> >>> + val = read_csr_perfcntr0();
> >>> + break;
> >>> + case 1:
> >>> + val = read_csr_perfcntr1();
> >>> + break;
> >>> + case 2:
> >>> + val = read_csr_perfcntr2();
> >>> + break;
> >>> + case 3:
> >>> + val = read_csr_perfcntr3();
> >>> + break;
> >>> + default:
> >>> + WARN_ONCE(1, "Invalid performance counter number (%d)\n", idx);
> >>> + return 0;
> >>> + }
> >>> +
> >>> + return val;
> >>> +}
> >>> +
> >>> +static void loongarch_pmu_write_counter(unsigned int idx, u64 val)
> >>> +{
> >>> + switch (idx) {
> >>> + case 0:
> >>> + write_csr_perfcntr0(val);
> >>> + return;
> >>> + case 1:
> >>> + write_csr_perfcntr1(val);
> >>> + return;
> >>> + case 2:
> >>> + write_csr_perfcntr2(val);
> >>> + return;
> >>> + case 3:
> >>> + write_csr_perfcntr3(val);
> >>> + return;
> >> Want a default branch for this function, similar to the read case?
> > Yes, that is needed.
> >
> >>> + }
> >>> +}
> >>> +
> >>> +static unsigned int loongarch_pmu_read_control(unsigned int idx)
> >>> +{
> >>> + unsigned int val = -1;
> >>> +
> >>> + switch (idx) {
> >>> + case 0:
> >>> + val = read_csr_perfctrl0();
> >>> + break;
> >>> + case 1:
> >>> + val = read_csr_perfctrl1();
> >>> + break;
> >>> + case 2:
> >>> + val = read_csr_perfctrl2();
> >>> + break;
> >>> + case 3:
> >>> + val = read_csr_perfctrl3();
> >>> + break;
> >>> + default:
> >>> + WARN_ONCE(1, "Invalid performance counter number (%d)\n", idx);
> >>> + return 0;
> >>> + }
> >>> +
> >>> + return val;
> >>> +}
> >>> +
> >>> +static void loongarch_pmu_write_control(unsigned int idx, unsigned int val)
> >>> +{
> >>> + switch (idx) {
> >>> + case 0:
> >>> + write_csr_perfctrl0(val);
> >>> + return;
> >>> + case 1:
> >>> + write_csr_perfctrl1(val);
> >>> + return;
> >>> + case 2:
> >>> + write_csr_perfctrl2(val);
> >>> + return;
> >>> + case 3:
> >>> + write_csr_perfctrl3(val);
> >>> + return;
> >> Similarly here.
> >>
> >>> + }
> >>> +}
> >>> +
> >>> +static int loongarch_pmu_alloc_counter(struct cpu_hw_events *cpuc,
> >>> + struct hw_perf_event *hwc)
> >>> +{
> >>> + int i;
> >>> +
> >>> + for (i = loongarch_pmu.num_counters - 1; i >= 0; i--) {
> >>> + if (!test_and_set_bit(i, cpuc->used_mask))
> >>> + return i;
> >>> + }
> >>> +
> >>> + return -EAGAIN;
> >>> +}
> >>> +
> >>> +static void loongarch_pmu_enable_event(struct hw_perf_event *evt, int idx)
> >>> +{
> >>> + struct perf_event *event = container_of(evt, struct perf_event, hw);
> >>> + struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
> >>> + unsigned int cpu;
> >>> +
> >>> + WARN_ON(idx < 0 || idx >= loongarch_pmu.num_counters);
> >>> +
> >>> + cpuc->saved_ctrl[idx] = M_PERFCTL_EVENT(evt->event_base & 0xff) |
> >>> + (evt->config_base & M_PERFCTL_CONFIG_MASK) |
> >>> + /* Make sure interrupt enabled. */
> >>> + CSR_PERFCTRL_IE;
> >>> +
> >>> + cpu = (event->cpu >= 0) ? event->cpu : smp_processor_id();
> >>> +
> >>> + pr_debug("Enabling perf counter for CPU%d\n", cpu);
> >>> + /*
> >>> + * We do not actually let the counter run. Leave it until start().
> >>> + */
> >>> +}
> >>> +
> >>> +static void loongarch_pmu_disable_event(int idx)
> >>> +{
> >>> + struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
> >>> + unsigned long flags;
> >>> +
> >>> + WARN_ON(idx < 0 || idx >= loongarch_pmu.num_counters);
> >>> +
> >>> + local_irq_save(flags);
> >>> + cpuc->saved_ctrl[idx] = loongarch_pmu_read_control(idx) &
> >>> + ~M_PERFCTL_COUNT_EVENT_WHENEVER;
> >>> + loongarch_pmu_write_control(idx, cpuc->saved_ctrl[idx]);
> >>> + local_irq_restore(flags);
> >>> +}
> >>> +
> >>> +static int loongarch_pmu_event_set_period(struct perf_event *event,
> >>> + struct hw_perf_event *hwc,
> >>> + int idx)
> >>> +{
> >>> + u64 left = local64_read(&hwc->period_left);
> >>> + u64 period = hwc->sample_period;
> >>> + int ret = 0;
> >>> +
> >>> + if (unlikely((left + period) & (1ULL << 63))) {
> >>> + /* left underflowed by more than period. */
> >>> + left = period;
> >>> + local64_set(&hwc->period_left, left);
> >>> + hwc->last_period = period;
> >>> + ret = 1;
> >>> + } else if (unlikely((left + period) <= period)) {
> >>> + /* left underflowed by less than period. */
> >>> + left += period;
> >>> + local64_set(&hwc->period_left, left);
> >>> + hwc->last_period = period;
> >>> + ret = 1;
> >>> + }
> >>> +
> >>> + if (left > loongarch_pmu.max_period) {
> >>> + left = loongarch_pmu.max_period;
> >>> + local64_set(&hwc->period_left, left);
> >>> + }
> >>> +
> >>> + local64_set(&hwc->prev_count, loongarch_pmu.overflow - left);
> >>> +
> >>> + loongarch_pmu.write_counter(idx, loongarch_pmu.overflow - left);
> >>> +
> >>> + perf_event_update_userpage(event);
> >>> +
> >>> + return ret;
> >>> +}
> >>> +
> >>> +static void loongarch_pmu_event_update(struct perf_event *event,
> >>> + struct hw_perf_event *hwc,
> >>> + int idx)
> >>> +{
> >>> + u64 delta;
> >>> + u64 prev_raw_count, new_raw_count;
> >>> +
> >>> +again:
> >>> + prev_raw_count = local64_read(&hwc->prev_count);
> >>> + new_raw_count = loongarch_pmu.read_counter(idx);
> >>> +
> >>> + if (local64_cmpxchg(&hwc->prev_count, prev_raw_count,
> >>> + new_raw_count) != prev_raw_count)
> >>> + goto again;
> >>> +
> >>> + delta = new_raw_count - prev_raw_count;
> >>> +
> >>> + local64_add(delta, &event->count);
> >>> + local64_sub(delta, &hwc->period_left);
> >>> +}
> >>> +
> >>> +static void loongarch_pmu_start(struct perf_event *event, int flags)
> >>> +{
> >>> + struct hw_perf_event *hwc = &event->hw;
> >>> +
> >>> + if (flags & PERF_EF_RELOAD)
> >>> + WARN_ON_ONCE(!(hwc->state & PERF_HES_UPTODATE));
> >>> +
> >>> + hwc->state = 0;
> >>> +
> >>> + /* Set the period for the event. */
> >>> + loongarch_pmu_event_set_period(event, hwc, hwc->idx);
> >>> +
> >>> + /* Enable the event. */
> >>> + loongarch_pmu_enable_event(hwc, hwc->idx);
> >>> +}
> >>> +
> >>> +static void loongarch_pmu_stop(struct perf_event *event, int flags)
> >>> +{
> >>> + struct hw_perf_event *hwc = &event->hw;
> >>> +
> >>> + if (!(hwc->state & PERF_HES_STOPPED)) {
> >>> + /* We are working on a local event. */
> >>> + loongarch_pmu_disable_event(hwc->idx);
> >>> + barrier();
> >>> + loongarch_pmu_event_update(event, hwc, hwc->idx);
> >>> + hwc->state |= PERF_HES_STOPPED | PERF_HES_UPTODATE;
> >>> + }
> >>> +}
> >>> +
> >>> +static int loongarch_pmu_add(struct perf_event *event, int flags)
> >>> +{
> >>> + struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
> >>> + struct hw_perf_event *hwc = &event->hw;
> >>> + int idx;
> >>> + int err = 0;
> >>> +
> >>> + perf_pmu_disable(event->pmu);
> >>> +
> >>> + /* To look for a free counter for this event. */
> >>> + idx = loongarch_pmu_alloc_counter(cpuc, hwc);
> >>> + if (idx < 0) {
> >>> + err = idx;
> >>> + goto out;
> >>> + }
> >>> +
> >>> + /*
> >>> + * If there is an event in the counter we are going to use then
> >>> + * make sure it is disabled.
> >>> + */
> >>> + event->hw.idx = idx;
> >>> + loongarch_pmu_disable_event(idx);
> >>> + cpuc->events[idx] = event;
> >>> +
> >>> + hwc->state = PERF_HES_STOPPED | PERF_HES_UPTODATE;
> >>> + if (flags & PERF_EF_START)
> >>> + loongarch_pmu_start(event, PERF_EF_RELOAD);
> >>> +
> >>> + /* Propagate our changes to the userspace mapping. */
> >>> + perf_event_update_userpage(event);
> >>> +
> >>> +out:
> >>> + perf_pmu_enable(event->pmu);
> >>> + return err;
> >>> +}
> >>> +
> >>> +static void loongarch_pmu_del(struct perf_event *event, int flags)
> >>> +{
> >>> + struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
> >>> + struct hw_perf_event *hwc = &event->hw;
> >>> + int idx = hwc->idx;
> >>> +
> >>> + WARN_ON(idx < 0 || idx >= loongarch_pmu.num_counters);
> >>> +
> >>> + loongarch_pmu_stop(event, PERF_EF_UPDATE);
> >>> + cpuc->events[idx] = NULL;
> >>> + clear_bit(idx, cpuc->used_mask);
> >>> +
> >>> + perf_event_update_userpage(event);
> >>> +}
> >>> +
> >>> +static void loongarch_pmu_read(struct perf_event *event)
> >>> +{
> >>> + struct hw_perf_event *hwc = &event->hw;
> >>> +
> >>> + /* Don't read disabled counters! */
> >>> + if (hwc->idx < 0)
> >>> + return;
> >>> +
> >>> + loongarch_pmu_event_update(event, hwc, hwc->idx);
> >>> +}
> >>> +
> >>> +static void loongarch_pmu_enable(struct pmu *pmu)
> >>> +{
> >>> + resume_local_counters();
> >>> +}
> >>> +
> >>> +static void loongarch_pmu_disable(struct pmu *pmu)
> >>> +{
> >>> + pause_local_counters();
> >>> +}
> >>> +
> >>> +static atomic_t active_events = ATOMIC_INIT(0);
> >>> +static DEFINE_MUTEX(pmu_reserve_mutex);
> >>> +
> >>> +static void reset_counters(void *arg);
> >>> +static int __hw_perf_event_init(struct perf_event *event);
> >>> +
> >>> +static void hw_perf_event_destroy(struct perf_event *event)
> >>> +{
> >>> + if (atomic_dec_and_mutex_lock(&active_events,
> >>> + &pmu_reserve_mutex)) {
> >>> + /*
> >>> + * We must not call the destroy function with interrupts
> >>> + * disabled.
> >>> + */
> >>> + on_each_cpu(reset_counters,
> >>> + (void *)(long)loongarch_pmu.num_counters, 1);
> >>> + mutex_unlock(&pmu_reserve_mutex);
> >>> + }
> >>> +}
> >>> +
> >>> +/* This is needed by specific irq handlers in perf_event_*.c */
> >>> +static void handle_associated_event(struct cpu_hw_events *cpuc,
> >>> + int idx, struct perf_sample_data *data,
> >>> + struct pt_regs *regs)
> >>> +{
> >>> + struct perf_event *event = cpuc->events[idx];
> >>> + struct hw_perf_event *hwc = &event->hw;
> >>> +
> >>> + loongarch_pmu_event_update(event, hwc, idx);
> >>> + data->period = event->hw.last_period;
> >>> + if (!loongarch_pmu_event_set_period(event, hwc, idx))
> >>> + return;
> >>> +
> >>> + if (perf_event_overflow(event, data, regs))
> >>> + loongarch_pmu_disable_event(idx);
> >>> +}
> >>> +
> >>> +static irqreturn_t pmu_handle_irq(int irq, void *dev)
> >>> +{
> >>> + int handled = IRQ_NONE;
> >>> + unsigned int counters = loongarch_pmu.num_counters;
> >>> + u64 counter;
> >>> + struct pt_regs *regs;
> >>> + struct perf_sample_data data;
> >>> + struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
> >>> +
> >>> + /*
> >>> + * First we pause the local counters, so that when we are locked
> >>> + * here, the counters are all paused. When it gets locked due to
> >>> + * perf_disable(), the timer interrupt handler will be delayed.
> >>> + *
> >>> + * See also loongarch_pmu_start().
> >>> + */
> >>> + pause_local_counters();
> >>> +
> >>> + regs = get_irq_regs();
> >>> +
> >>> + perf_sample_data_init(&data, 0, 0);
> >>> +
> >>> + switch (counters) {
> >>> +#define HANDLE_COUNTER(n) \
> >>> + case n + 1: \
> >>> + if (test_bit(n, cpuc->used_mask)) { \
> >>> + counter = loongarch_pmu.read_counter(n); \
> >>> + if (counter & loongarch_pmu.overflow) { \
> >>> + handle_associated_event(cpuc, n, &data, regs); \
> >>> + handled = IRQ_HANDLED; \
> >>> + } \
> >>> + }
> >>> + HANDLE_COUNTER(3)
> >>> + fallthrough;
> >>> + HANDLE_COUNTER(2)
> >>> + fallthrough;
> >>> + HANDLE_COUNTER(1)
> >>> + fallthrough;
> >>> + HANDLE_COUNTER(0)
> >>> + }
> >>> +
> >>> + resume_local_counters();
> >>> +
> >>> + /*
> >>> + * Do all the work for the pending perf events. We can do this
> >>> + * in here because the performance counter interrupt is a regular
> >>> + * interrupt, not NMI.
> >>> + */
> >>> + if (handled == IRQ_HANDLED)
> >>> + irq_work_run();
> >>> +
> >>> + return handled;
> >>> +}
> >>> +
> >>> +static int get_pmc_irq(void)
> >>> +{
> >>> + struct irq_domain *d = irq_find_matching_fwnode(cpuintc_handle, DOMAIN_BUS_ANY);
> >>> +
> >>> + if (d)
> >>> + return irq_create_mapping(d, EXCCODE_PMC - EXCCODE_INT_START);
> >>> +
> >>> + return -EINVAL;
> >>> +}
> >>> +
> >>> +static int loongarch_pmu_event_init(struct perf_event *event)
> >>> +{
> >>> + int r, irq;
> >>> + unsigned long flags;
> >>> +
> >>> + /* does not support taken branch sampling */
> >>> + if (has_branch_stack(event))
> >>> + return -EOPNOTSUPP;
> >>> +
> >>> + switch (event->attr.type) {
> >>> + case PERF_TYPE_RAW:
> >>> + case PERF_TYPE_HARDWARE:
> >>> + case PERF_TYPE_HW_CACHE:
> >>> + break;
> >>> +
> >>> + default:
> >>> + /* Init it to avoid false validate_group */
> >>> + event->hw.event_base = 0xffffffff;
> >>> + return -ENOENT;
> >>> + }
> >>> +
> >>> + if (event->cpu >= 0 && !cpu_online(event->cpu))
> >>> + return -ENODEV;
> >>> +
> >>> + irq = get_pmc_irq();
> >>> + flags = IRQF_PERCPU | IRQF_NOBALANCING | IRQF_NO_THREAD | IRQF_NO_SUSPEND | IRQF_SHARED;
> >>> + if (!atomic_inc_not_zero(&active_events)) {
> >>> + mutex_lock(&pmu_reserve_mutex);
> >>> + if (atomic_read(&active_events) == 0) {
> >>> + r = request_irq(irq, pmu_handle_irq,
> >>> + flags, "Perf_PMU", &loongarch_pmu);
> >>> + if (r < 0) {
> >>> + pr_warn("PMU IRQ request failed\n");
> >>> + return -ENODEV;
> >>> + }
> >>> + }
> >>> + atomic_inc(&active_events);
> >>> + mutex_unlock(&pmu_reserve_mutex);
> >>> + }
> >>> +
> >>> + return __hw_perf_event_init(event);
> >>> +}
> >>> +
> >>> +static struct pmu pmu = {
> >>> + .pmu_enable = loongarch_pmu_enable,
> >>> + .pmu_disable = loongarch_pmu_disable,
> >>> + .event_init = loongarch_pmu_event_init,
> >>> + .add = loongarch_pmu_add,
> >>> + .del = loongarch_pmu_del,
> >>> + .start = loongarch_pmu_start,
> >>> + .stop = loongarch_pmu_stop,
> >>> + .read = loongarch_pmu_read,
> >>> +};
> >>> +
> >>> +static unsigned int loongarch_pmu_perf_event_encode(const struct loongarch_perf_event *pev)
> >>> +{
> >>> + return (pev->event_id & 0xff);
> >>> +}
> >>> +
> >>> +static const struct loongarch_perf_event *loongarch_pmu_map_general_event(int idx)
> >>> +{
> >>> + const struct loongarch_perf_event *pev;
> >>> +
> >>> + pev = &(*loongarch_pmu.general_event_map)[idx];
> >>> +
> >>> + if (pev->event_id == HW_OP_UNSUPPORTED)
> >>> + return ERR_PTR(-ENOENT);
> >>> +
> >>> + return pev;
> >>> +}
> >>> +
> >>> +static const struct loongarch_perf_event *loongarch_pmu_map_cache_event(u64 config)
> >>> +{
> >>> + unsigned int cache_type, cache_op, cache_result;
> >>> + const struct loongarch_perf_event *pev;
> >>> +
> >>> + cache_type = (config >> 0) & 0xff;
> >>> + if (cache_type >= PERF_COUNT_HW_CACHE_MAX)
> >>> + return ERR_PTR(-EINVAL);
> >>> +
> >>> + cache_op = (config >> 8) & 0xff;
> >>> + if (cache_op >= PERF_COUNT_HW_CACHE_OP_MAX)
> >>> + return ERR_PTR(-EINVAL);
> >>> +
> >>> + cache_result = (config >> 16) & 0xff;
> >>> + if (cache_result >= PERF_COUNT_HW_CACHE_RESULT_MAX)
> >>> + return ERR_PTR(-EINVAL);
> >>> +
> >>> + pev = &((*loongarch_pmu.cache_event_map)
> >>> + [cache_type]
> >>> + [cache_op]
> >>> + [cache_result]);
> >>> +
> >>> + if (pev->event_id == CACHE_OP_UNSUPPORTED)
> >>> + return ERR_PTR(-ENOENT);
> >>> +
> >>> + return pev;
> >>> +}
> >>> +
> >>> +static int validate_group(struct perf_event *event)
> >>> +{
> >>> + struct perf_event *sibling, *leader = event->group_leader;
> >>> + struct cpu_hw_events fake_cpuc;
> >>> +
> >>> + memset(&fake_cpuc, 0, sizeof(fake_cpuc));
> >>> +
> >>> + if (loongarch_pmu_alloc_counter(&fake_cpuc, &leader->hw) < 0)
> >>> + return -EINVAL;
> >>> +
> >>> + for_each_sibling_event(sibling, leader) {
> >>> + if (loongarch_pmu_alloc_counter(&fake_cpuc, &sibling->hw) < 0)
> >>> + return -EINVAL;
> >>> + }
> >>> +
> >>> + if (loongarch_pmu_alloc_counter(&fake_cpuc, &event->hw) < 0)
> >>> + return -EINVAL;
> >>> +
> >>> + return 0;
> >>> +}
> >>> +
> >>> +static void reset_counters(void *arg)
> >>> +{
> >>> + int counters = (int)(long)arg;
> >>> +
> >>> + switch (counters) {
> >>> + case 4:
> >>> + loongarch_pmu_write_control(3, 0);
> >>> + loongarch_pmu.write_counter(3, 0);
> >>> + fallthrough;
> >>> + case 3:
> >>> + loongarch_pmu_write_control(2, 0);
> >>> + loongarch_pmu.write_counter(2, 0);
> >>> + fallthrough;
> >>> + case 2:
> >>> + loongarch_pmu_write_control(1, 0);
> >>> + loongarch_pmu.write_counter(1, 0);
> >>> + fallthrough;
> >>> + case 1:
> >>> + loongarch_pmu_write_control(0, 0);
> >>> + loongarch_pmu.write_counter(0, 0);
> >>> + }
> >>> +}
> >>> +
> >>> +static const struct loongarch_perf_event loongson_new_event_map[PERF_COUNT_HW_MAX] = {
> >>> + PERF_MAP_ALL_UNSUPPORTED,
> >>> + [PERF_COUNT_HW_CPU_CYCLES] = { 0x00 },
> >>> + [PERF_COUNT_HW_INSTRUCTIONS] = { 0x01 },
> >>> + [PERF_COUNT_HW_CACHE_REFERENCES] = { 0x08 },
> >>> + [PERF_COUNT_HW_CACHE_MISSES] = { 0x09 },
> >>> + [PERF_COUNT_HW_BRANCH_INSTRUCTIONS] = { 0x02 },
> >>> + [PERF_COUNT_HW_BRANCH_MISSES] = { 0x03 },
> >>> +};
> >>> +
> >>> +static const struct loongarch_perf_event loongson_new_cache_map
> >>> + [PERF_COUNT_HW_CACHE_MAX]
> >>> + [PERF_COUNT_HW_CACHE_OP_MAX]
> >>> + [PERF_COUNT_HW_CACHE_RESULT_MAX] = {
> >>> +PERF_CACHE_MAP_ALL_UNSUPPORTED,
> >>> +[C(L1D)] = {
> >>> + /*
> >>> + * Like some other architectures (e.g. ARM), the performance
> >>> + * counters don't differentiate between read and write
> >>> + * accesses/misses, so this isn't strictly correct, but it's the
> >>> + * best we can do. Writes and reads get combined.
> >>> + */
> >>> + [C(OP_READ)] = {
> >>> + [C(RESULT_ACCESS)] = { 0x8 },
> >>> + [C(RESULT_MISS)] = { 0x9 },
> >>> + },
> >>> + [C(OP_WRITE)] = {
> >>> + [C(RESULT_ACCESS)] = { 0x8 },
> >>> + [C(RESULT_MISS)] = { 0x9 },
> >>> + },
> >>> + [C(OP_PREFETCH)] = {
> >>> + [C(RESULT_ACCESS)] = { 0xaa },
> >>> + [C(RESULT_MISS)] = { 0xa9 },
> >>> + },
> >>> +},
> >>> +[C(L1I)] = {
> >>> + [C(OP_READ)] = {
> >>> + [C(RESULT_ACCESS)] = { 0x6 },
> >>> + [C(RESULT_MISS)] = { 0x7 },
> >>> + },
> >>> +},
> >>> +[C(LL)] = {
> >>> + [C(OP_READ)] = {
> >>> + [C(RESULT_ACCESS)] = { 0xc },
> >>> + [C(RESULT_MISS)] = { 0xd },
> >>> + },
> >>> + [C(OP_WRITE)] = {
> >>> + [C(RESULT_ACCESS)] = { 0xc },
> >>> + [C(RESULT_MISS)] = { 0xd },
> >>> + },
> >>> +},
> >>> +[C(ITLB)] = {
> >>> + [C(OP_READ)] = {
> >>> + [C(RESULT_MISS)] = { 0x3b },
> >>> + },
> >>> +},
> >>> +[C(DTLB)] = {
> >>> + [C(OP_READ)] = {
> >>> + [C(RESULT_ACCESS)] = { 0x4 },
> >>> + [C(RESULT_MISS)] = { 0x3c },
> >>> + },
> >>> + [C(OP_WRITE)] = {
> >>> + [C(RESULT_ACCESS)] = { 0x4 },
> >>> + [C(RESULT_MISS)] = { 0x3c },
> >>> + },
> >>> +},
> >>> +[C(BPU)] = {
> >>> + /* Using the same code for *HW_BRANCH* */
> >>> + [C(OP_READ)] = {
> >>> + [C(RESULT_ACCESS)] = { 0x02 },
> >>> + [C(RESULT_MISS)] = { 0x03 },
> >>> + },
> >>> +},
> >>> +};
> >>> +
> >>> +static int __hw_perf_event_init(struct perf_event *event)
> >>> +{
> >>> + struct perf_event_attr *attr = &event->attr;
> >>> + struct hw_perf_event *hwc = &event->hw;
> >>> + const struct loongarch_perf_event *pev;
> >>> + int err;
> >>> +
> >>> + /* Returning LoongArch event descriptor for generic perf event. */
> >>> + if (PERF_TYPE_HARDWARE == event->attr.type) {
> >>> + if (event->attr.config >= PERF_COUNT_HW_MAX)
> >>> + return -EINVAL;
> >>> + pev = loongarch_pmu_map_general_event(event->attr.config);
> >>> + } else if (PERF_TYPE_HW_CACHE == event->attr.type) {
> >>> + pev = loongarch_pmu_map_cache_event(event->attr.config);
> >>> + } else if (PERF_TYPE_RAW == event->attr.type) {
> >>> + /* We are working on the global raw event. */
> >>> + mutex_lock(&raw_event_mutex);
> >>> + pev = loongarch_pmu.map_raw_event(event->attr.config);
> >>> + } else {
> >>> + /* The event type is not (yet) supported. */
> >>> + return -EOPNOTSUPP;
> >>> + }
> >>> +
> >>> + if (IS_ERR(pev)) {
> >>> + if (PERF_TYPE_RAW == event->attr.type)
> >>> + mutex_unlock(&raw_event_mutex);
> >>> + return PTR_ERR(pev);
> >>> + }
> >>> +
> >>> + /*
> >>> + * We allow max flexibility on how each individual counter shared
> >>> + * by the single CPU operates (the mode exclusion and the range).
> >>> + */
> >>> + hwc->config_base = CSR_PERFCTRL_IE;
> >>> +
> >>> + hwc->event_base = loongarch_pmu_perf_event_encode(pev);
> >>> + if (PERF_TYPE_RAW == event->attr.type)
> >>> + mutex_unlock(&raw_event_mutex);
> >>> +
> >>> + if (!attr->exclude_user) {
> >>> + hwc->config_base |= CSR_PERFCTRL_PLV3;
> >>> + hwc->config_base |= CSR_PERFCTRL_PLV2;
> >>> + }
> >>> + if (!attr->exclude_kernel) {
> >>> + hwc->config_base |= CSR_PERFCTRL_PLV0;
> >>> + }
> >>> + if (!attr->exclude_hv) {
> >>> + hwc->config_base |= CSR_PERFCTRL_PLV1;
> >>> + }
> >>> +
> >>> + hwc->config_base &= M_PERFCTL_CONFIG_MASK;
> >>> + /*
> >>> + * The event can belong to another cpu. We do not assign a local
> >>> + * counter for it for now.
> >>> + */
> >>> + hwc->idx = -1;
> >>> + hwc->config = 0;
> >>> +
> >>> + if (!hwc->sample_period) {
> >>> + hwc->sample_period = loongarch_pmu.max_period;
> >>> + hwc->last_period = hwc->sample_period;
> >>> + local64_set(&hwc->period_left, hwc->sample_period);
> >>> + }
> >>> +
> >>> + err = 0;
> >>> + if (event->group_leader != event)
> >>> + err = validate_group(event);
> >>> +
> >>> + event->destroy = hw_perf_event_destroy;
> >>> +
> >>> + if (err)
> >>> + event->destroy(event);
> >>> +
> >>> + return err;
> >>> +}
> >>> +
> >>> +static void pause_local_counters(void)
> >>> +{
> >>> + struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
> >>> + int ctr = loongarch_pmu.num_counters;
> >>> + unsigned long flags;
> >>> +
> >>> + local_irq_save(flags);
> >>> + do {
> >>> + ctr--;
> >>> + cpuc->saved_ctrl[ctr] = loongarch_pmu_read_control(ctr);
> >>> + loongarch_pmu_write_control(ctr, cpuc->saved_ctrl[ctr] &
> >>> + ~M_PERFCTL_COUNT_EVENT_WHENEVER);
> >>> + } while (ctr > 0);
> >>> + local_irq_restore(flags);
> >>> +}
> >>> +
> >>> +static void resume_local_counters(void)
> >>> +{
> >>> + struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
> >>> + int ctr = loongarch_pmu.num_counters;
> >>> +
> >>> + do {
> >>> + ctr--;
> >>> + loongarch_pmu_write_control(ctr, cpuc->saved_ctrl[ctr]);
> >>> + } while (ctr > 0);
> >>> +}
> >>> +
> >>> +static const struct loongarch_perf_event *loongarch_pmu_map_raw_event(u64 config)
> >>> +{
> >>> + raw_event.event_id = config & 0xff;
> >>> +
> >>> + return &raw_event;
> >>> +}
> >>> +
> >>> +static int __init
> >>> +init_hw_perf_events(void)
> >>> +{
> >>> + int counters = 4;
> >>> +
> >>> + if (!cpu_has_pmp)
> >>> + return -ENODEV;
> >>> +
> >>> + pr_info("Performance counters: ");
> >>> +
> >>> + loongarch_pmu.num_counters = counters;
> >>> + loongarch_pmu.max_period = (1ULL << 63) - 1;
> >>> + loongarch_pmu.valid_count = (1ULL << 63) - 1;
> >>> + loongarch_pmu.overflow = 1ULL << 63;
> >>> + loongarch_pmu.name = "loongarch/loongson64";
> >>> + loongarch_pmu.read_counter = loongarch_pmu_read_counter;
> >>> + loongarch_pmu.write_counter = loongarch_pmu_write_counter;
> >>> + loongarch_pmu.map_raw_event = loongarch_pmu_map_raw_event;
> >>> + loongarch_pmu.general_event_map = &loongson_new_event_map;
> >>> + loongarch_pmu.cache_event_map = &loongson_new_cache_map;
> >>> +
> >>> + on_each_cpu(reset_counters, (void *)(long)counters, 1);
> >>> +
> >>> + pr_cont("%s PMU enabled, %d %d-bit counters available to each "
> >>> + "CPU.\n", loongarch_pmu.name, counters, 64);
> >>> +
> >>> + perf_pmu_register(&pmu, "cpu", PERF_TYPE_RAW);
> >>> +
> >>> + return 0;
> >>> +}
> >>> +early_initcall(init_hw_perf_events);
> >>> diff --git a/arch/loongarch/kernel/perf_regs.c b/arch/loongarch/kernel/perf_regs.c
> >>> new file mode 100644
> >>> index 000000000000..a5e9768e8414
> >>> --- /dev/null
> >>> +++ b/arch/loongarch/kernel/perf_regs.c
> >>> @@ -0,0 +1,50 @@
> >>> +// SPDX-License-Identifier: GPL-2.0
> >>> +/*
> >>> + * Copyright (C) 2022 Loongson Technology Corporation Limited
> >> And this file.
> > OK, thanks.
> >
> > Huacai
> >>> + */
> >>> +
> >>> +#include <linux/perf_event.h>
> >>> +
> >>> +#include <asm/ptrace.h>
> >>> +
> >>> +#ifdef CONFIG_32BIT
> >>> +u64 perf_reg_abi(struct task_struct *tsk)
> >>> +{
> >>> + return PERF_SAMPLE_REGS_ABI_32;
> >>> +}
> >>> +#else /* Must be CONFIG_64BIT */
> >>> +u64 perf_reg_abi(struct task_struct *tsk)
> >>> +{
> >>> + if (test_tsk_thread_flag(tsk, TIF_32BIT_REGS))
> >>> + return PERF_SAMPLE_REGS_ABI_32;
> >>> + else
> >>> + return PERF_SAMPLE_REGS_ABI_64;
> >>> +}
> >>> +#endif /* CONFIG_32BIT */
> >>> +
> >>> +int perf_reg_validate(u64 mask)
> >>> +{
> >>> + if (!mask)
> >>> + return -EINVAL;
> >>> + if (mask & ~((1ull << PERF_REG_LOONGARCH_MAX) - 1))
> >>> + return -EINVAL;
> >>> + return 0;
> >>> +}
> >>> +
> >>> +u64 perf_reg_value(struct pt_regs *regs, int idx)
> >>> +{
> >>> + if (WARN_ON_ONCE((u32)idx >= PERF_REG_LOONGARCH_MAX))
> >>> + return 0;
> >>> +
> >>> + if ((u32)idx == PERF_REG_LOONGARCH_PC)
> >>> + return regs->csr_era;
> >>> +
> >>> + return regs->regs[idx];
> >>> +}
> >>> +
> >>> +void perf_get_regs_user(struct perf_regs *regs_user,
> >>> + struct pt_regs *regs)
> >>> +{
> >>> + regs_user->regs = task_pt_regs(current);
> >>> + regs_user->abi = perf_reg_abi(current);
> >>> +}
> >> --
> >> WANG "xen0n" Xuerui
> >>
> >> Linux/LoongArch mailing list: https://lore.kernel.org/loongarch/
> >>
>