v11:
-- Rebase on the latest code
-- Address all the review comments, thank you all
-- Modify arch_prepare_kprobe() and setup_singlestep()
to make the probe logic more clear
-- Mark some assembler symbols as non-kprobe-able
-- Use common function sign_extend64()
-- Test 20 times about 36 hours for all the 71 assembler
functions annotated with SYM_CODE_START and SYM_FUNC_START
under arch/loongarch, especially test memset alone for 10
hours, no hang problems
v10:
-- Remove sign_extend() based on the latest code
-- Rename insns_are_not_supported() to insns_not_supported()
-- Rename insns_are_not_simulated() to insns_not_simulated()
-- Set KPROBE_HIT_SSDONE if cur->post_handler is not NULL
-- Enable preemption for KPROBE_REENTER in kprobe_fault_handler()
v9:
-- Rename sign_extended() to sign_extend()
-- Modify kprobe_fault_handler() to handle all of kprobe_status
v8:
-- Put "regs->csr_prmd &= ~CSR_PRMD_PIE;" ahead to save one line
-- Add code comment of preempt_disable()
-- Put kprobe_page_fault() in __do_page_fault()
-- Modify the check condition of break insn in kprobe_breakpoint_handler()
v7:
-- Remove stop_machine_cpuslocked() related code
v6:
-- Add a new patch to redefine larch_insn_patch_text() with
stop_machine_cpuslocked()
-- Modify kprobe_breakpoint_handler() to consider the original
insn is break and return the correct value
-- Modify do_bp() to refresh bcode when original insn is break
v5:
-- Rebase on the latest code
-- Use stop_machine_cpuslocked() to modify insn to avoid CPU race
v4:
-- Remove kprobe_exceptions_notify() in kprobes.c
-- Call kprobe_breakpoint_handler() and kprobe_singlestep_handler()
in do_bp()
v3:
-- Rebase on the latest code
-- Check the alignment of PC in simu_branch() and simu_pc()
-- Add ibar in flush_insn_slot()
-- Rename kprobe_{pre,post}_handler() to {post_}kprobe_handler
-- Add preempt_disable() and preempt_enable_no_resched()
-- Remove r0 save/restore and do some minor changes
in kprobes_trampoline.S
-- Do not enable CONFIG_KPROBES by default
v2:
-- Split simu_branch() and simu_pc() into a single patch
-- Call kprobe_page_fault() in do_page_fault()
-- Add kprobes_trampoline.S for kretprobe
Tiezhu Yang (6):
LoongArch: Simulate branch and PC* instructions
LoongArch: Add kprobe support
LoongArch: Add kretprobe support
LoongArch: Mark some assembler symbols as non-kprobe-able
samples/kprobes: Add LoongArch support
LoongArch: Use common function sign_extend64()
arch/loongarch/Kconfig | 2 +
arch/loongarch/include/asm/asm.h | 10 +
arch/loongarch/include/asm/inst.h | 28 +-
arch/loongarch/include/asm/kprobes.h | 58 +++++
arch/loongarch/include/asm/ptrace.h | 1 +
arch/loongarch/kernel/Makefile | 2 +
arch/loongarch/kernel/alternative.c | 6 +-
arch/loongarch/kernel/entry.S | 1 +
arch/loongarch/kernel/inst.c | 123 +++++++++
arch/loongarch/kernel/kprobes.c | 405 +++++++++++++++++++++++++++++
arch/loongarch/kernel/kprobes_trampoline.S | 96 +++++++
arch/loongarch/kernel/traps.c | 11 +-
arch/loongarch/lib/memcpy.S | 3 +
arch/loongarch/mm/fault.c | 3 +
samples/kprobes/kprobe_example.c | 8 +
15 files changed, 741 insertions(+), 16 deletions(-)
create mode 100644 arch/loongarch/include/asm/kprobes.h
create mode 100644 arch/loongarch/kernel/kprobes.c
create mode 100644 arch/loongarch/kernel/kprobes_trampoline.S
--
2.1.0
There exists a common function sign_extend64() to sign extend a 64-bit
value using specified bit as sign-bit in include/linux/bitops.h, it is
more efficient, let us use it and remove the arch-specific sign_extend()
under arch/loongarch.
Suggested-by: Jinyang He <[email protected]>
Signed-off-by: Tiezhu Yang <[email protected]>
---
arch/loongarch/include/asm/inst.h | 8 --------
arch/loongarch/kernel/alternative.c | 6 +++---
2 files changed, 3 insertions(+), 11 deletions(-)
diff --git a/arch/loongarch/include/asm/inst.h b/arch/loongarch/include/asm/inst.h
index e0771d2..ba18ce8 100644
--- a/arch/loongarch/include/asm/inst.h
+++ b/arch/loongarch/include/asm/inst.h
@@ -397,14 +397,6 @@ static inline bool unsigned_imm_check(unsigned long val, unsigned int bit)
return val < (1UL << bit);
}
-static inline unsigned long sign_extend(unsigned long val, unsigned int idx)
-{
- if (!is_imm_negative(val, idx + 1))
- return ((1UL << idx) - 1) & val;
- else
- return ~((1UL << idx) - 1) | val;
-}
-
#define DEF_EMIT_REG0I26_FORMAT(NAME, OP) \
static inline void emit_##NAME(union loongarch_instruction *insn, \
int offset) \
diff --git a/arch/loongarch/kernel/alternative.c b/arch/loongarch/kernel/alternative.c
index c5aebea..4ad1384 100644
--- a/arch/loongarch/kernel/alternative.c
+++ b/arch/loongarch/kernel/alternative.c
@@ -74,7 +74,7 @@ static void __init_or_module recompute_jump(union loongarch_instruction *buf,
switch (src->reg0i26_format.opcode) {
case b_op:
case bl_op:
- jump_addr = cur_pc + sign_extend((si_h << 16 | si_l) << 2, 27);
+ jump_addr = cur_pc + sign_extend64((si_h << 16 | si_l) << 2, 27);
if (in_alt_jump(jump_addr, start, end))
return;
offset = jump_addr - pc;
@@ -93,7 +93,7 @@ static void __init_or_module recompute_jump(union loongarch_instruction *buf,
fallthrough;
case beqz_op:
case bnez_op:
- jump_addr = cur_pc + sign_extend((si_h << 16 | si_l) << 2, 22);
+ jump_addr = cur_pc + sign_extend64((si_h << 16 | si_l) << 2, 22);
if (in_alt_jump(jump_addr, start, end))
return;
offset = jump_addr - pc;
@@ -112,7 +112,7 @@ static void __init_or_module recompute_jump(union loongarch_instruction *buf,
case bge_op:
case bltu_op:
case bgeu_op:
- jump_addr = cur_pc + sign_extend(si << 2, 17);
+ jump_addr = cur_pc + sign_extend64(si << 2, 17);
if (in_alt_jump(jump_addr, start, end))
return;
offset = jump_addr - pc;
--
2.1.0
According to LoongArch Reference Manual, simulate branch and PC*
instructions, this is preparation for later patch.
Link: https://loongson.github.io/LoongArch-Documentation/LoongArch-Vol1-EN.html#branch-instructions
Link: https://loongson.github.io/LoongArch-Documentation/LoongArch-Vol1-EN.html#_pcaddi_pcaddu121_pcaddu18l_pcalau12i
Co-developed-by: Jinyang He <[email protected]>
Signed-off-by: Jinyang He <[email protected]>
Signed-off-by: Tiezhu Yang <[email protected]>
---
arch/loongarch/include/asm/inst.h | 5 ++
arch/loongarch/include/asm/ptrace.h | 1 +
arch/loongarch/kernel/inst.c | 123 ++++++++++++++++++++++++++++++++++++
3 files changed, 129 insertions(+)
diff --git a/arch/loongarch/include/asm/inst.h b/arch/loongarch/include/asm/inst.h
index a463b51..c83cfb7 100644
--- a/arch/loongarch/include/asm/inst.h
+++ b/arch/loongarch/include/asm/inst.h
@@ -7,6 +7,7 @@
#include <linux/types.h>
#include <asm/asm.h>
+#include <asm/ptrace.h>
#define INSN_NOP 0x03400000
#define INSN_BREAK 0x002a0000
@@ -32,6 +33,7 @@ enum reg1i20_op {
lu12iw_op = 0x0a,
lu32id_op = 0x0b,
pcaddi_op = 0x0c,
+ pcalau12i_op = 0x0d,
pcaddu12i_op = 0x0e,
pcaddu18i_op = 0x0f,
};
@@ -351,6 +353,9 @@ static inline bool is_stack_alloc_ins(union loongarch_instruction *ip)
is_imm12_negative(ip->reg2i12_format.immediate);
}
+void simu_pc(struct pt_regs *regs, union loongarch_instruction insn);
+void simu_branch(struct pt_regs *regs, union loongarch_instruction insn);
+
int larch_insn_read(void *addr, u32 *insnp);
int larch_insn_write(void *addr, u32 insn);
int larch_insn_patch_text(void *addr, u32 insn);
diff --git a/arch/loongarch/include/asm/ptrace.h b/arch/loongarch/include/asm/ptrace.h
index 59c4608..58596c4 100644
--- a/arch/loongarch/include/asm/ptrace.h
+++ b/arch/loongarch/include/asm/ptrace.h
@@ -6,6 +6,7 @@
#define _ASM_PTRACE_H
#include <asm/page.h>
+#include <asm/irqflags.h>
#include <asm/thread_info.h>
#include <uapi/asm/ptrace.h>
diff --git a/arch/loongarch/kernel/inst.c b/arch/loongarch/kernel/inst.c
index badc590..258ef26 100644
--- a/arch/loongarch/kernel/inst.c
+++ b/arch/loongarch/kernel/inst.c
@@ -10,6 +10,129 @@
static DEFINE_RAW_SPINLOCK(patch_lock);
+void simu_pc(struct pt_regs *regs, union loongarch_instruction insn)
+{
+ unsigned long pc = regs->csr_era;
+ unsigned int rd = insn.reg1i20_format.rd;
+ unsigned int imm = insn.reg1i20_format.immediate;
+
+ if (pc & 3) {
+ pr_warn("%s: invalid pc 0x%lx\n", __func__, pc);
+ return;
+ }
+
+ switch (insn.reg1i20_format.opcode) {
+ case pcaddi_op:
+ regs->regs[rd] = pc + sign_extend64(imm << 2, 21);
+ break;
+ case pcaddu12i_op:
+ regs->regs[rd] = pc + sign_extend64(imm << 12, 31);
+ break;
+ case pcaddu18i_op:
+ regs->regs[rd] = pc + sign_extend64(imm << 18, 37);
+ break;
+ case pcalau12i_op:
+ regs->regs[rd] = pc + sign_extend64(imm << 12, 31);
+ regs->regs[rd] &= ~((1 << 12) - 1);
+ break;
+ default:
+ pr_info("%s: unknown opcode\n", __func__);
+ return;
+ }
+
+ regs->csr_era += LOONGARCH_INSN_SIZE;
+}
+
+void simu_branch(struct pt_regs *regs, union loongarch_instruction insn)
+{
+ unsigned int imm, imm_l, imm_h, rd, rj;
+ unsigned long pc = regs->csr_era;
+
+ if (pc & 3) {
+ pr_warn("%s: invalid pc 0x%lx\n", __func__, pc);
+ return;
+ }
+
+ imm_l = insn.reg0i26_format.immediate_l;
+ imm_h = insn.reg0i26_format.immediate_h;
+ switch (insn.reg0i26_format.opcode) {
+ case b_op:
+ regs->csr_era = pc + sign_extend64((imm_h << 16 | imm_l) << 2, 27);
+ return;
+ case bl_op:
+ regs->csr_era = pc + sign_extend64((imm_h << 16 | imm_l) << 2, 27);
+ regs->regs[1] = pc + LOONGARCH_INSN_SIZE;
+ return;
+ }
+
+ imm_l = insn.reg1i21_format.immediate_l;
+ imm_h = insn.reg1i21_format.immediate_h;
+ rj = insn.reg1i21_format.rj;
+ switch (insn.reg1i21_format.opcode) {
+ case beqz_op:
+ if (regs->regs[rj] == 0)
+ regs->csr_era = pc + sign_extend64((imm_h << 16 | imm_l) << 2, 22);
+ else
+ regs->csr_era = pc + LOONGARCH_INSN_SIZE;
+ return;
+ case bnez_op:
+ if (regs->regs[rj] != 0)
+ regs->csr_era = pc + sign_extend64((imm_h << 16 | imm_l) << 2, 22);
+ else
+ regs->csr_era = pc + LOONGARCH_INSN_SIZE;
+ return;
+ }
+
+ imm = insn.reg2i16_format.immediate;
+ rj = insn.reg2i16_format.rj;
+ rd = insn.reg2i16_format.rd;
+ switch (insn.reg2i16_format.opcode) {
+ case beq_op:
+ if (regs->regs[rj] == regs->regs[rd])
+ regs->csr_era = pc + sign_extend64(imm << 2, 17);
+ else
+ regs->csr_era = pc + LOONGARCH_INSN_SIZE;
+ break;
+ case bne_op:
+ if (regs->regs[rj] != regs->regs[rd])
+ regs->csr_era = pc + sign_extend64(imm << 2, 17);
+ else
+ regs->csr_era = pc + LOONGARCH_INSN_SIZE;
+ break;
+ case blt_op:
+ if ((long)regs->regs[rj] < (long)regs->regs[rd])
+ regs->csr_era = pc + sign_extend64(imm << 2, 17);
+ else
+ regs->csr_era = pc + LOONGARCH_INSN_SIZE;
+ break;
+ case bge_op:
+ if ((long)regs->regs[rj] >= (long)regs->regs[rd])
+ regs->csr_era = pc + sign_extend64(imm << 2, 17);
+ else
+ regs->csr_era = pc + LOONGARCH_INSN_SIZE;
+ break;
+ case bltu_op:
+ if (regs->regs[rj] < regs->regs[rd])
+ regs->csr_era = pc + sign_extend64(imm << 2, 17);
+ else
+ regs->csr_era = pc + LOONGARCH_INSN_SIZE;
+ break;
+ case bgeu_op:
+ if (regs->regs[rj] >= regs->regs[rd])
+ regs->csr_era = pc + sign_extend64(imm << 2, 17);
+ else
+ regs->csr_era = pc + LOONGARCH_INSN_SIZE;
+ break;
+ case jirl_op:
+ regs->csr_era = regs->regs[rj] + sign_extend64(imm << 2, 17);
+ regs->regs[rd] = pc + LOONGARCH_INSN_SIZE;
+ break;
+ default:
+ pr_info("%s: unknown opcode\n", __func__);
+ return;
+ }
+}
+
int larch_insn_read(void *addr, u32 *insnp)
{
int ret;
--
2.1.0
Some assembler symbols are not kprobe safe, such as handle_syscall
(used as syscall exception handler), *memcpy* (may cause recursive
exceptions), they can not be instrumented, just blacklist them for
kprobing.
Here is a related problem and discussion:
Link: https://lore.kernel.org/lkml/[email protected]/
Signed-off-by: Tiezhu Yang <[email protected]>
---
arch/loongarch/include/asm/asm.h | 10 ++++++++++
arch/loongarch/kernel/entry.S | 1 +
arch/loongarch/lib/memcpy.S | 3 +++
3 files changed, 14 insertions(+)
diff --git a/arch/loongarch/include/asm/asm.h b/arch/loongarch/include/asm/asm.h
index 40eea6a..f591b32 100644
--- a/arch/loongarch/include/asm/asm.h
+++ b/arch/loongarch/include/asm/asm.h
@@ -188,4 +188,14 @@
#define PTRLOG 3
#endif
+/* Annotate a function as being unsuitable for kprobes. */
+#ifdef CONFIG_KPROBES
+#define _ASM_NOKPROBE(name) \
+ .pushsection "_kprobe_blacklist", "aw"; \
+ .quad name; \
+ .popsection
+#else
+#define _ASM_NOKPROBE(name)
+#endif
+
#endif /* __ASM_ASM_H */
diff --git a/arch/loongarch/kernel/entry.S b/arch/loongarch/kernel/entry.S
index d53b631..55e23b1 100644
--- a/arch/loongarch/kernel/entry.S
+++ b/arch/loongarch/kernel/entry.S
@@ -67,6 +67,7 @@ SYM_FUNC_START(handle_syscall)
RESTORE_ALL_AND_RET
SYM_FUNC_END(handle_syscall)
+_ASM_NOKPROBE(handle_syscall)
SYM_CODE_START(ret_from_fork)
bl schedule_tail # a0 = struct task_struct *prev
diff --git a/arch/loongarch/lib/memcpy.S b/arch/loongarch/lib/memcpy.S
index 7c07d59..3b7e1de 100644
--- a/arch/loongarch/lib/memcpy.S
+++ b/arch/loongarch/lib/memcpy.S
@@ -17,6 +17,7 @@ SYM_FUNC_START(memcpy)
ALTERNATIVE "b __memcpy_generic", \
"b __memcpy_fast", CPU_FEATURE_UAL
SYM_FUNC_END(memcpy)
+_ASM_NOKPROBE(memcpy)
EXPORT_SYMBOL(memcpy)
@@ -41,6 +42,7 @@ SYM_FUNC_START(__memcpy_generic)
2: move a0, a3
jr ra
SYM_FUNC_END(__memcpy_generic)
+_ASM_NOKPROBE(__memcpy_generic)
/*
* void *__memcpy_fast(void *dst, const void *src, size_t n)
@@ -93,3 +95,4 @@ SYM_FUNC_START(__memcpy_fast)
3: move a0, a3
jr ra
SYM_FUNC_END(__memcpy_fast)
+_ASM_NOKPROBE(__memcpy_fast)
--
2.1.0
Kprobe allows you to trap at almost any kernel address and execute a
callback function, this commit adds kprobe support for LoongArch.
Signed-off-by: Tiezhu Yang <[email protected]>
---
arch/loongarch/Kconfig | 1 +
arch/loongarch/include/asm/inst.h | 15 ++
arch/loongarch/include/asm/kprobes.h | 58 ++++++
arch/loongarch/kernel/Makefile | 2 +
arch/loongarch/kernel/kprobes.c | 378 +++++++++++++++++++++++++++++++++++
arch/loongarch/kernel/traps.c | 11 +-
arch/loongarch/mm/fault.c | 3 +
7 files changed, 463 insertions(+), 5 deletions(-)
create mode 100644 arch/loongarch/include/asm/kprobes.h
create mode 100644 arch/loongarch/kernel/kprobes.c
diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
index 9be74ec..ce930f2 100644
--- a/arch/loongarch/Kconfig
+++ b/arch/loongarch/Kconfig
@@ -103,6 +103,7 @@ config LOONGARCH
select HAVE_IOREMAP_PROT
select HAVE_IRQ_EXIT_ON_IRQ_STACK
select HAVE_IRQ_TIME_ACCOUNTING
+ select HAVE_KPROBES
select HAVE_MOD_ARCH_SPECIFIC
select HAVE_NMI
select HAVE_PCI
diff --git a/arch/loongarch/include/asm/inst.h b/arch/loongarch/include/asm/inst.h
index c83cfb7..e0771d2 100644
--- a/arch/loongarch/include/asm/inst.h
+++ b/arch/loongarch/include/asm/inst.h
@@ -24,6 +24,10 @@
#define ADDR_IMM(addr, INSN) ((addr & ADDR_IMMMASK_##INSN) >> ADDR_IMMSHIFT_##INSN)
+enum reg0i15_op {
+ break_op = 0x54,
+};
+
enum reg0i26_op {
b_op = 0x14,
bl_op = 0x15,
@@ -180,6 +184,11 @@ enum reg3sa2_op {
alsld_op = 0x16,
};
+struct reg0i15_format {
+ unsigned int immediate : 15;
+ unsigned int opcode : 17;
+};
+
struct reg0i26_format {
unsigned int immediate_h : 10;
unsigned int immediate_l : 16;
@@ -265,6 +274,7 @@ struct reg3sa2_format {
union loongarch_instruction {
unsigned int word;
+ struct reg0i15_format reg0i15_format;
struct reg0i26_format reg0i26_format;
struct reg1i20_format reg1i20_format;
struct reg1i21_format reg1i21_format;
@@ -323,6 +333,11 @@ static inline bool is_imm_negative(unsigned long val, unsigned int bit)
return val & (1UL << (bit - 1));
}
+static inline bool is_break_ins(union loongarch_instruction *ip)
+{
+ return ip->reg0i15_format.opcode == break_op;
+}
+
static inline bool is_pc_ins(union loongarch_instruction *ip)
{
return ip->reg1i20_format.opcode >= pcaddi_op &&
diff --git a/arch/loongarch/include/asm/kprobes.h b/arch/loongarch/include/asm/kprobes.h
new file mode 100644
index 0000000..7b9fc3e
--- /dev/null
+++ b/arch/loongarch/include/asm/kprobes.h
@@ -0,0 +1,58 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef __ASM_LOONGARCH_KPROBES_H
+#define __ASM_LOONGARCH_KPROBES_H
+
+#include <asm-generic/kprobes.h>
+
+#ifdef CONFIG_KPROBES
+
+#include <asm/inst.h>
+#include <asm/cacheflush.h>
+
+#define __ARCH_WANT_KPROBES_INSN_SLOT
+#define MAX_INSN_SIZE 2
+
+#define flush_insn_slot(p) \
+do { \
+ if (p->addr) \
+ flush_icache_range((unsigned long)p->addr, \
+ (unsigned long)p->addr + \
+ (MAX_INSN_SIZE * sizeof(kprobe_opcode_t))); \
+} while (0)
+
+#define kretprobe_blacklist_size 0
+
+typedef union loongarch_instruction kprobe_opcode_t;
+
+/* Architecture specific copy of original instruction */
+struct arch_specific_insn {
+ /* copy of the original instruction */
+ kprobe_opcode_t *insn;
+ /* restore address after simulation */
+ unsigned long restore;
+};
+
+struct prev_kprobe {
+ struct kprobe *kp;
+ unsigned int status;
+};
+
+/* per-cpu kprobe control block */
+struct kprobe_ctlblk {
+ unsigned int kprobe_status;
+ unsigned long saved_status;
+ struct prev_kprobe prev_kprobe;
+};
+
+void arch_remove_kprobe(struct kprobe *p);
+bool kprobe_fault_handler(struct pt_regs *regs, int trapnr);
+bool kprobe_breakpoint_handler(struct pt_regs *regs);
+bool kprobe_singlestep_handler(struct pt_regs *regs);
+
+#else /* !CONFIG_KPROBES */
+
+static inline bool kprobe_breakpoint_handler(struct pt_regs *regs) { return false; }
+static inline bool kprobe_singlestep_handler(struct pt_regs *regs) { return false; }
+
+#endif /* CONFIG_KPROBES */
+#endif /* __ASM_LOONGARCH_KPROBES_H */
diff --git a/arch/loongarch/kernel/Makefile b/arch/loongarch/kernel/Makefile
index fcaa024..6fe4a4e 100644
--- a/arch/loongarch/kernel/Makefile
+++ b/arch/loongarch/kernel/Makefile
@@ -47,4 +47,6 @@ obj-$(CONFIG_UNWINDER_PROLOGUE) += unwind_prologue.o
obj-$(CONFIG_PERF_EVENTS) += perf_event.o perf_regs.o
+obj-$(CONFIG_KPROBES) += kprobes.o
+
CPPFLAGS_vmlinux.lds := $(KBUILD_CFLAGS)
diff --git a/arch/loongarch/kernel/kprobes.c b/arch/loongarch/kernel/kprobes.c
new file mode 100644
index 0000000..a0c2f9d
--- /dev/null
+++ b/arch/loongarch/kernel/kprobes.c
@@ -0,0 +1,378 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/kdebug.h>
+#include <linux/kprobes.h>
+#include <linux/preempt.h>
+#include <asm/break.h>
+
+static const union loongarch_instruction breakpoint_insn = {
+ .reg0i15_format = {
+ .opcode = break_op,
+ .immediate = BRK_KPROBE_BP,
+ }
+};
+
+static const union loongarch_instruction singlestep_insn = {
+ .reg0i15_format = {
+ .opcode = break_op,
+ .immediate = BRK_KPROBE_SSTEPBP,
+ }
+};
+
+DEFINE_PER_CPU(struct kprobe *, current_kprobe);
+DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
+
+static void post_kprobe_handler(struct kprobe *, struct kprobe_ctlblk *, struct pt_regs *);
+
+static bool insns_not_supported(union loongarch_instruction insn)
+{
+ switch (insn.reg2i14_format.opcode) {
+ case llw_op:
+ case lld_op:
+ case scw_op:
+ case scd_op:
+ pr_notice("kprobe: ll and sc instructions are not supported\n");
+ return true;
+ }
+
+ switch (insn.reg1i21_format.opcode) {
+ case bceqz_op:
+ pr_notice("kprobe: bceqz and bcnez instructions are not supported\n");
+ return true;
+ }
+
+ return false;
+}
+NOKPROBE_SYMBOL(insns_not_supported);
+
+static bool insn_need_simulation(struct kprobe *p)
+{
+ if (is_pc_ins(&p->opcode))
+ return true;
+
+ if (is_branch_ins(&p->opcode))
+ return true;
+
+ return false;
+}
+NOKPROBE_SYMBOL(insn_need_simulation);
+
+static void arch_simulate_insn(struct kprobe *p, struct pt_regs *regs)
+{
+ if (is_pc_ins(&p->opcode))
+ simu_pc(regs, p->opcode);
+ else if (is_branch_ins(&p->opcode))
+ simu_branch(regs, p->opcode);
+}
+NOKPROBE_SYMBOL(arch_simulate_insn);
+
+static void arch_prepare_ss_slot(struct kprobe *p)
+{
+ p->ainsn.insn[0] = *p->addr;
+ p->ainsn.insn[1] = singlestep_insn;
+ p->ainsn.restore = (unsigned long)p->addr + LOONGARCH_INSN_SIZE;
+}
+NOKPROBE_SYMBOL(arch_prepare_ss_slot);
+
+static void arch_prepare_simulate(struct kprobe *p)
+{
+ p->ainsn.restore = 0;
+}
+NOKPROBE_SYMBOL(arch_prepare_simulate);
+
+int arch_prepare_kprobe(struct kprobe *p)
+{
+ /* copy instruction */
+ p->opcode = *p->addr;
+
+ /* decode instruction */
+ if (insns_not_supported(p->opcode))
+ return -EINVAL;
+
+ if (insn_need_simulation(p)) {
+ p->ainsn.insn = NULL;
+ } else {
+ p->ainsn.insn = get_insn_slot();
+ if (!p->ainsn.insn)
+ return -ENOMEM;
+ }
+
+ /* prepare the instruction */
+ if (p->ainsn.insn)
+ arch_prepare_ss_slot(p);
+ else
+ arch_prepare_simulate(p);
+
+ return 0;
+}
+NOKPROBE_SYMBOL(arch_prepare_kprobe);
+
+/* Install breakpoint in text */
+void arch_arm_kprobe(struct kprobe *p)
+{
+ *p->addr = breakpoint_insn;
+ flush_insn_slot(p);
+}
+NOKPROBE_SYMBOL(arch_arm_kprobe);
+
+/* Remove breakpoint from text */
+void arch_disarm_kprobe(struct kprobe *p)
+{
+ *p->addr = p->opcode;
+ flush_insn_slot(p);
+}
+NOKPROBE_SYMBOL(arch_disarm_kprobe);
+
+void arch_remove_kprobe(struct kprobe *p)
+{
+ if (p->ainsn.insn) {
+ free_insn_slot(p->ainsn.insn, 0);
+ p->ainsn.insn = NULL;
+ }
+}
+NOKPROBE_SYMBOL(arch_remove_kprobe);
+
+static void save_previous_kprobe(struct kprobe_ctlblk *kcb)
+{
+ kcb->prev_kprobe.kp = kprobe_running();
+ kcb->prev_kprobe.status = kcb->kprobe_status;
+}
+NOKPROBE_SYMBOL(save_previous_kprobe);
+
+static void restore_previous_kprobe(struct kprobe_ctlblk *kcb)
+{
+ __this_cpu_write(current_kprobe, kcb->prev_kprobe.kp);
+ kcb->kprobe_status = kcb->prev_kprobe.status;
+}
+NOKPROBE_SYMBOL(restore_previous_kprobe);
+
+static void set_current_kprobe(struct kprobe *p)
+{
+ __this_cpu_write(current_kprobe, p);
+}
+NOKPROBE_SYMBOL(set_current_kprobe);
+
+/*
+ * Interrupts need to be disabled before single-step mode is set,
+ * and not reenabled until after single-step mode ends.
+ * Without disabling interrupt on local CPU, there is a chance of
+ * interrupt occurrence in the period of exception return and start
+ * of out-of-line single-step, that result in wrongly single stepping
+ * into the interrupt handler.
+ */
+static void save_local_irqflag(struct kprobe_ctlblk *kcb,
+ struct pt_regs *regs)
+{
+ kcb->saved_status = regs->csr_prmd;
+ regs->csr_prmd &= ~CSR_PRMD_PIE;
+}
+NOKPROBE_SYMBOL(save_local_irqflag);
+
+static void restore_local_irqflag(struct kprobe_ctlblk *kcb,
+ struct pt_regs *regs)
+{
+ regs->csr_prmd = kcb->saved_status;
+}
+NOKPROBE_SYMBOL(restore_local_irqflag);
+
+static void setup_singlestep(struct kprobe *p, struct pt_regs *regs,
+ struct kprobe_ctlblk *kcb, int reenter)
+{
+ if (reenter) {
+ save_previous_kprobe(kcb);
+ set_current_kprobe(p);
+ kcb->kprobe_status = KPROBE_REENTER;
+ } else {
+ kcb->kprobe_status = KPROBE_HIT_SS;
+ }
+
+ if (p->ainsn.insn) {
+ /* IRQs and single stepping do not mix well */
+ save_local_irqflag(kcb, regs);
+ /* set ip register to prepare for single stepping */
+ regs->csr_era = (unsigned long)p->ainsn.insn;
+ } else {
+ /* simulate single steping */
+ arch_simulate_insn(p, regs);
+ /* now go for post processing */
+ post_kprobe_handler(p, kcb, regs);
+ }
+}
+NOKPROBE_SYMBOL(setup_singlestep);
+
+static bool reenter_kprobe(struct kprobe *p, struct pt_regs *regs,
+ struct kprobe_ctlblk *kcb)
+{
+ switch (kcb->kprobe_status) {
+ case KPROBE_HIT_SSDONE:
+ case KPROBE_HIT_ACTIVE:
+ case KPROBE_HIT_SS:
+ kprobes_inc_nmissed_count(p);
+ setup_singlestep(p, regs, kcb, 1);
+ break;
+ case KPROBE_REENTER:
+ pr_warn("Failed to recover from reentered kprobes.\n");
+ dump_kprobe(p);
+ WARN_ON_ONCE(1);
+ break;
+ default:
+ WARN_ON(1);
+ return false;
+ }
+
+ return true;
+}
+NOKPROBE_SYMBOL(reenter_kprobe);
+
+static void post_kprobe_handler(struct kprobe *cur, struct kprobe_ctlblk *kcb,
+ struct pt_regs *regs)
+{
+ /* return addr restore if non-branching insn */
+ if (cur->ainsn.restore != 0)
+ instruction_pointer_set(regs, cur->ainsn.restore);
+
+ /* restore back original saved kprobe variables and continue */
+ if (kcb->kprobe_status == KPROBE_REENTER) {
+ restore_previous_kprobe(kcb);
+ preempt_enable_no_resched();
+ return;
+ }
+
+ /*
+ * update the kcb status even if the cur->post_handler is
+ * not set because reset_curent_kprobe() doesn't update kcb.
+ */
+ kcb->kprobe_status = KPROBE_HIT_SSDONE;
+ if (cur->post_handler)
+ cur->post_handler(cur, regs, 0);
+
+ reset_current_kprobe();
+ preempt_enable_no_resched();
+}
+NOKPROBE_SYMBOL(post_kprobe_handler);
+
+bool kprobe_breakpoint_handler(struct pt_regs *regs)
+{
+ struct kprobe_ctlblk *kcb;
+ struct kprobe *p, *cur_kprobe;
+ kprobe_opcode_t *addr = (kprobe_opcode_t *)regs->csr_era;
+
+ /*
+ * We don't want to be preempted for the entire
+ * duration of kprobe processing.
+ */
+ preempt_disable();
+ kcb = get_kprobe_ctlblk();
+ cur_kprobe = kprobe_running();
+
+ p = get_kprobe(addr);
+ if (p) {
+ if (cur_kprobe) {
+ if (reenter_kprobe(p, regs, kcb))
+ return true;
+ } else {
+ /* Probe hit */
+ set_current_kprobe(p);
+ kcb->kprobe_status = KPROBE_HIT_ACTIVE;
+
+ /*
+ * If we have no pre-handler or it returned 0, we
+ * continue with normal processing. If we have a
+ * pre-handler and it returned non-zero, it will
+ * modify the execution path and no need to single
+ * stepping. Let's just reset current kprobe and exit.
+ *
+ * pre_handler can hit a breakpoint and can step thru
+ * before return.
+ */
+ if (!p->pre_handler || !p->pre_handler(p, regs)) {
+ setup_singlestep(p, regs, kcb, 0);
+ } else {
+ reset_current_kprobe();
+ preempt_enable_no_resched();
+ }
+ return true;
+ }
+ }
+
+ if (addr->word != breakpoint_insn.word) {
+ /*
+ * The breakpoint instruction was removed right
+ * after we hit it. Another cpu has removed
+ * either a probepoint or a debugger breakpoint
+ * at this address. In either case, no further
+ * handling of this interrupt is appropriate.
+ * Return back to original instruction, and continue.
+ */
+ regs->csr_era = (unsigned long)addr;
+ preempt_enable_no_resched();
+ return true;
+ }
+
+ preempt_enable_no_resched();
+ return false;
+}
+NOKPROBE_SYMBOL(kprobe_breakpoint_handler);
+
+bool kprobe_singlestep_handler(struct pt_regs *regs)
+{
+ struct kprobe *cur = kprobe_running();
+ struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+ unsigned long addr = instruction_pointer(regs);
+
+ if (cur && (kcb->kprobe_status & (KPROBE_HIT_SS | KPROBE_REENTER)) &&
+ ((unsigned long)&cur->ainsn.insn[1] == addr)) {
+ restore_local_irqflag(kcb, regs);
+ post_kprobe_handler(cur, kcb, regs);
+ return true;
+ }
+
+ preempt_enable_no_resched();
+ return false;
+}
+NOKPROBE_SYMBOL(kprobe_singlestep_handler);
+
+bool kprobe_fault_handler(struct pt_regs *regs, int trapnr)
+{
+ struct kprobe *cur = kprobe_running();
+ struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+
+ switch (kcb->kprobe_status) {
+ case KPROBE_HIT_SS:
+ case KPROBE_REENTER:
+ /*
+ * We are here because the instruction being single
+ * stepped caused a page fault. We reset the current
+ * kprobe and the ip points back to the probe address
+ * and allow the page fault handler to continue as a
+ * normal page fault.
+ */
+ regs->csr_era = (unsigned long)cur->addr;
+ WARN_ON_ONCE(!instruction_pointer(regs));
+
+ if (kcb->kprobe_status == KPROBE_REENTER) {
+ restore_previous_kprobe(kcb);
+ } else {
+ restore_local_irqflag(kcb, regs);
+ reset_current_kprobe();
+ }
+ preempt_enable_no_resched();
+ break;
+ }
+ return false;
+}
+NOKPROBE_SYMBOL(kprobe_fault_handler);
+
+/*
+ * Provide a blacklist of symbols identifying ranges which cannot be kprobed.
+ * This blacklist is exposed to userspace via debugfs (kprobes/blacklist).
+ */
+int __init arch_populate_kprobe_blacklist(void)
+{
+ return kprobe_add_area_blacklist((unsigned long)__irqentry_text_start,
+ (unsigned long)__irqentry_text_end);
+}
+
+int __init arch_init_kprobes(void)
+{
+ return 0;
+}
diff --git a/arch/loongarch/kernel/traps.c b/arch/loongarch/kernel/traps.c
index a19bb32..5af6475 100644
--- a/arch/loongarch/kernel/traps.c
+++ b/arch/loongarch/kernel/traps.c
@@ -435,7 +435,10 @@ asmlinkage void noinstr do_bp(struct pt_regs *regs)
unsigned long era = exception_era(regs);
irqentry_state_t state = irqentry_enter(regs);
- local_irq_enable();
+ /* Enable interrupt if enabled in parent context */
+ if (likely(regs->csr_prmd & CSR_PRMD_PIE))
+ local_irq_enable();
+
current->thread.trap_nr = read_csr_excode();
if (__get_inst(&opcode, (u32 *)era, user))
goto out_sigsegv;
@@ -448,14 +451,12 @@ asmlinkage void noinstr do_bp(struct pt_regs *regs)
*/
switch (bcode) {
case BRK_KPROBE_BP:
- if (notify_die(DIE_BREAK, "Kprobe", regs, bcode,
- current->thread.trap_nr, SIGTRAP) == NOTIFY_STOP)
+ if (kprobe_breakpoint_handler(regs))
goto out;
else
break;
case BRK_KPROBE_SSTEPBP:
- if (notify_die(DIE_SSTEPBP, "Kprobe_SingleStep", regs, bcode,
- current->thread.trap_nr, SIGTRAP) == NOTIFY_STOP)
+ if (kprobe_singlestep_handler(regs))
goto out;
else
break;
diff --git a/arch/loongarch/mm/fault.c b/arch/loongarch/mm/fault.c
index 1ccd536..449087b 100644
--- a/arch/loongarch/mm/fault.c
+++ b/arch/loongarch/mm/fault.c
@@ -135,6 +135,9 @@ static void __kprobes __do_page_fault(struct pt_regs *regs,
struct vm_area_struct *vma = NULL;
vm_fault_t fault;
+ if (kprobe_page_fault(regs, current->thread.trap_nr))
+ return;
+
/*
* We fault-in kernel-space virtual memory on-demand. The
* 'reference' page table is init_mm.pgd.
--
2.1.0
Add LoongArch specific info in handler_pre() and handler_post().
Signed-off-by: Tiezhu Yang <[email protected]>
---
samples/kprobes/kprobe_example.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/samples/kprobes/kprobe_example.c b/samples/kprobes/kprobe_example.c
index fd346f5..ef44c61 100644
--- a/samples/kprobes/kprobe_example.c
+++ b/samples/kprobes/kprobe_example.c
@@ -55,6 +55,10 @@ static int __kprobes handler_pre(struct kprobe *p, struct pt_regs *regs)
pr_info("<%s> p->addr, 0x%p, ip = 0x%lx, flags = 0x%lx\n",
p->symbol_name, p->addr, regs->psw.addr, regs->flags);
#endif
+#ifdef CONFIG_LOONGARCH
+ pr_info("<%s> p->addr = 0x%p, era = 0x%lx, estat = 0x%lx\n",
+ p->symbol_name, p->addr, regs->csr_era, regs->csr_estat);
+#endif
/* A dump_stack() here will give a stack backtrace */
return 0;
@@ -92,6 +96,10 @@ static void __kprobes handler_post(struct kprobe *p, struct pt_regs *regs,
pr_info("<%s> p->addr, 0x%p, flags = 0x%lx\n",
p->symbol_name, p->addr, regs->flags);
#endif
+#ifdef CONFIG_LOONGARCH
+ pr_info("<%s> p->addr = 0x%p, estat = 0x%lx\n",
+ p->symbol_name, p->addr, regs->csr_estat);
+#endif
}
static int __init kprobe_init(void)
--
2.1.0
Use the generic kretprobe trampoline handler to add kretprobe support
for LoongArch.
Signed-off-by: Tiezhu Yang <[email protected]>
---
arch/loongarch/Kconfig | 1 +
arch/loongarch/kernel/Makefile | 2 +-
arch/loongarch/kernel/kprobes.c | 27 +++++++++
arch/loongarch/kernel/kprobes_trampoline.S | 96 ++++++++++++++++++++++++++++++
4 files changed, 125 insertions(+), 1 deletion(-)
create mode 100644 arch/loongarch/kernel/kprobes_trampoline.S
diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
index ce930f2..134a2f8 100644
--- a/arch/loongarch/Kconfig
+++ b/arch/loongarch/Kconfig
@@ -104,6 +104,7 @@ config LOONGARCH
select HAVE_IRQ_EXIT_ON_IRQ_STACK
select HAVE_IRQ_TIME_ACCOUNTING
select HAVE_KPROBES
+ select HAVE_KRETPROBES
select HAVE_MOD_ARCH_SPECIFIC
select HAVE_NMI
select HAVE_PCI
diff --git a/arch/loongarch/kernel/Makefile b/arch/loongarch/kernel/Makefile
index 6fe4a4e..7ca6519 100644
--- a/arch/loongarch/kernel/Makefile
+++ b/arch/loongarch/kernel/Makefile
@@ -47,6 +47,6 @@ obj-$(CONFIG_UNWINDER_PROLOGUE) += unwind_prologue.o
obj-$(CONFIG_PERF_EVENTS) += perf_event.o perf_regs.o
-obj-$(CONFIG_KPROBES) += kprobes.o
+obj-$(CONFIG_KPROBES) += kprobes.o kprobes_trampoline.o
CPPFLAGS_vmlinux.lds := $(KBUILD_CFLAGS)
diff --git a/arch/loongarch/kernel/kprobes.c b/arch/loongarch/kernel/kprobes.c
index a0c2f9d..ced9c4c 100644
--- a/arch/loongarch/kernel/kprobes.c
+++ b/arch/loongarch/kernel/kprobes.c
@@ -372,6 +372,33 @@ int __init arch_populate_kprobe_blacklist(void)
(unsigned long)__irqentry_text_end);
}
+/* Called from __kretprobe_trampoline */
+void __used *trampoline_probe_handler(struct pt_regs *regs)
+{
+ return (void *)kretprobe_trampoline_handler(regs, NULL);
+}
+NOKPROBE_SYMBOL(trampoline_probe_handler);
+
+/* assembler function that handles the kretprobes must not be probed itself */
+NOKPROBE_SYMBOL(__kretprobe_trampoline);
+
+void arch_prepare_kretprobe(struct kretprobe_instance *ri,
+ struct pt_regs *regs)
+{
+ ri->ret_addr = (kprobe_opcode_t *)regs->regs[1];
+ ri->fp = NULL;
+
+ /* Replace the return addr with trampoline addr */
+ regs->regs[1] = (unsigned long)&__kretprobe_trampoline;
+}
+NOKPROBE_SYMBOL(arch_prepare_kretprobe);
+
+int arch_trampoline_kprobe(struct kprobe *p)
+{
+ return 0;
+}
+NOKPROBE_SYMBOL(arch_trampoline_kprobe);
+
int __init arch_init_kprobes(void)
{
return 0;
diff --git a/arch/loongarch/kernel/kprobes_trampoline.S b/arch/loongarch/kernel/kprobes_trampoline.S
new file mode 100644
index 0000000..af94b0d
--- /dev/null
+++ b/arch/loongarch/kernel/kprobes_trampoline.S
@@ -0,0 +1,96 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+#include <linux/linkage.h>
+#include <asm/stackframe.h>
+
+ .text
+
+ .macro save_all_base_regs
+ cfi_st ra, PT_R1
+ cfi_st tp, PT_R2
+ cfi_st a0, PT_R4
+ cfi_st a1, PT_R5
+ cfi_st a2, PT_R6
+ cfi_st a3, PT_R7
+ cfi_st a4, PT_R8
+ cfi_st a5, PT_R9
+ cfi_st a6, PT_R10
+ cfi_st a7, PT_R11
+ cfi_st t0, PT_R12
+ cfi_st t1, PT_R13
+ cfi_st t2, PT_R14
+ cfi_st t3, PT_R15
+ cfi_st t4, PT_R16
+ cfi_st t5, PT_R17
+ cfi_st t6, PT_R18
+ cfi_st t7, PT_R19
+ cfi_st t8, PT_R20
+ cfi_st u0, PT_R21
+ cfi_st fp, PT_R22
+ cfi_st s0, PT_R23
+ cfi_st s1, PT_R24
+ cfi_st s2, PT_R25
+ cfi_st s3, PT_R26
+ cfi_st s4, PT_R27
+ cfi_st s5, PT_R28
+ cfi_st s6, PT_R29
+ cfi_st s7, PT_R30
+ cfi_st s8, PT_R31
+ csrrd t0, LOONGARCH_CSR_CRMD
+ andi t0, t0, 0x7 /* extract bit[1:0] PLV, bit[2] IE */
+ LONG_S t0, sp, PT_CRMD
+ .endm
+
+ .macro restore_all_base_regs
+ cfi_ld tp, PT_R2
+ cfi_ld a0, PT_R4
+ cfi_ld a1, PT_R5
+ cfi_ld a2, PT_R6
+ cfi_ld a3, PT_R7
+ cfi_ld a4, PT_R8
+ cfi_ld a5, PT_R9
+ cfi_ld a6, PT_R10
+ cfi_ld a7, PT_R11
+ cfi_ld t0, PT_R12
+ cfi_ld t1, PT_R13
+ cfi_ld t2, PT_R14
+ cfi_ld t3, PT_R15
+ cfi_ld t4, PT_R16
+ cfi_ld t5, PT_R17
+ cfi_ld t6, PT_R18
+ cfi_ld t7, PT_R19
+ cfi_ld t8, PT_R20
+ cfi_ld u0, PT_R21
+ cfi_ld fp, PT_R22
+ cfi_ld s0, PT_R23
+ cfi_ld s1, PT_R24
+ cfi_ld s2, PT_R25
+ cfi_ld s3, PT_R26
+ cfi_ld s4, PT_R27
+ cfi_ld s5, PT_R28
+ cfi_ld s6, PT_R29
+ cfi_ld s7, PT_R30
+ cfi_ld s8, PT_R31
+ LONG_L t0, sp, PT_CRMD
+ li.d t1, 0x7 /* mask bit[1:0] PLV, bit[2] IE */
+ csrxchg t0, t1, LOONGARCH_CSR_CRMD
+ .endm
+
+SYM_CODE_START(__kretprobe_trampoline)
+ addi.d sp, sp, -PT_SIZE
+ save_all_base_regs
+
+ addi.d t0, sp, PT_SIZE
+ LONG_S t0, sp, PT_R3
+
+ move a0, sp /* pt_regs */
+
+ bl trampoline_probe_handler
+
+ /* use the result as the return-address */
+ move ra, a0
+
+ restore_all_base_regs
+ addi.d sp, sp, PT_SIZE
+
+ jr ra
+SYM_CODE_END(__kretprobe_trampoline)
--
2.1.0
Hi Tiezhu,
Thank you for the patch! Perhaps something to improve:
[auto build test WARNING on linus/master]
[also build test WARNING on v6.2-rc3 next-20230113]
[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/Tiezhu-Yang/LoongArch-Simulate-branch-and-PC-instructions/20230114-173012
patch link: https://lore.kernel.org/r/1673688444-24251-4-git-send-email-yangtiezhu%40loongson.cn
patch subject: [PATCH v11 3/6] LoongArch: Add kretprobe support
config: loongarch-allmodconfig
compiler: loongarch64-linux-gcc (GCC) 12.1.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/intel-lab-lkp/linux/commit/da766ea35a574bece74a5068aad708b5773b2981
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Tiezhu-Yang/LoongArch-Simulate-branch-and-PC-instructions/20230114-173012
git checkout da766ea35a574bece74a5068aad708b5773b2981
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=loongarch olddefconfig
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=loongarch SHELL=/bin/bash arch/loongarch/kernel/
If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <[email protected]>
Note: functions only called from assembly code should be annotated with the asmlinkage attribute
All warnings (new ones prefixed by >>):
>> arch/loongarch/kernel/kprobes.c:376:14: warning: no previous prototype for 'trampoline_probe_handler' [-Wmissing-prototypes]
376 | void __used *trampoline_probe_handler(struct pt_regs *regs)
| ^~~~~~~~~~~~~~~~~~~~~~~~
vim +/trampoline_probe_handler +376 arch/loongarch/kernel/kprobes.c
374
375 /* Called from __kretprobe_trampoline */
> 376 void __used *trampoline_probe_handler(struct pt_regs *regs)
377 {
378 return (void *)kretprobe_trampoline_handler(regs, NULL);
379 }
380 NOKPROBE_SYMBOL(trampoline_probe_handler);
381
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests
I queued this patch, but others need more reviews.
Huacai
On Sat, Jan 14, 2023 at 5:27 PM Tiezhu Yang <[email protected]> wrote:
>
> There exists a common function sign_extend64() to sign extend a 64-bit
> value using specified bit as sign-bit in include/linux/bitops.h, it is
> more efficient, let us use it and remove the arch-specific sign_extend()
> under arch/loongarch.
>
> Suggested-by: Jinyang He <[email protected]>
> Signed-off-by: Tiezhu Yang <[email protected]>
> ---
> arch/loongarch/include/asm/inst.h | 8 --------
> arch/loongarch/kernel/alternative.c | 6 +++---
> 2 files changed, 3 insertions(+), 11 deletions(-)
>
> diff --git a/arch/loongarch/include/asm/inst.h b/arch/loongarch/include/asm/inst.h
> index e0771d2..ba18ce8 100644
> --- a/arch/loongarch/include/asm/inst.h
> +++ b/arch/loongarch/include/asm/inst.h
> @@ -397,14 +397,6 @@ static inline bool unsigned_imm_check(unsigned long val, unsigned int bit)
> return val < (1UL << bit);
> }
>
> -static inline unsigned long sign_extend(unsigned long val, unsigned int idx)
> -{
> - if (!is_imm_negative(val, idx + 1))
> - return ((1UL << idx) - 1) & val;
> - else
> - return ~((1UL << idx) - 1) | val;
> -}
> -
> #define DEF_EMIT_REG0I26_FORMAT(NAME, OP) \
> static inline void emit_##NAME(union loongarch_instruction *insn, \
> int offset) \
> diff --git a/arch/loongarch/kernel/alternative.c b/arch/loongarch/kernel/alternative.c
> index c5aebea..4ad1384 100644
> --- a/arch/loongarch/kernel/alternative.c
> +++ b/arch/loongarch/kernel/alternative.c
> @@ -74,7 +74,7 @@ static void __init_or_module recompute_jump(union loongarch_instruction *buf,
> switch (src->reg0i26_format.opcode) {
> case b_op:
> case bl_op:
> - jump_addr = cur_pc + sign_extend((si_h << 16 | si_l) << 2, 27);
> + jump_addr = cur_pc + sign_extend64((si_h << 16 | si_l) << 2, 27);
> if (in_alt_jump(jump_addr, start, end))
> return;
> offset = jump_addr - pc;
> @@ -93,7 +93,7 @@ static void __init_or_module recompute_jump(union loongarch_instruction *buf,
> fallthrough;
> case beqz_op:
> case bnez_op:
> - jump_addr = cur_pc + sign_extend((si_h << 16 | si_l) << 2, 22);
> + jump_addr = cur_pc + sign_extend64((si_h << 16 | si_l) << 2, 22);
> if (in_alt_jump(jump_addr, start, end))
> return;
> offset = jump_addr - pc;
> @@ -112,7 +112,7 @@ static void __init_or_module recompute_jump(union loongarch_instruction *buf,
> case bge_op:
> case bltu_op:
> case bgeu_op:
> - jump_addr = cur_pc + sign_extend(si << 2, 17);
> + jump_addr = cur_pc + sign_extend64(si << 2, 17);
> if (in_alt_jump(jump_addr, start, end))
> return;
> offset = jump_addr - pc;
> --
> 2.1.0
>
On 01/15/2023 07:17 PM, kernel test robot wrote:
> Hi Tiezhu,
>
> Thank you for the patch! Perhaps something to improve:
>
> [auto build test WARNING on linus/master]
> [also build test WARNING on v6.2-rc3 next-20230113]
> [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/Tiezhu-Yang/LoongArch-Simulate-branch-and-PC-instructions/20230114-173012
> patch link: https://lore.kernel.org/r/1673688444-24251-4-git-send-email-yangtiezhu%40loongson.cn
> patch subject: [PATCH v11 3/6] LoongArch: Add kretprobe support
> config: loongarch-allmodconfig
> compiler: loongarch64-linux-gcc (GCC) 12.1.0
> reproduce (this is a W=1 build):
> wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
> chmod +x ~/bin/make.cross
> # https://github.com/intel-lab-lkp/linux/commit/da766ea35a574bece74a5068aad708b5773b2981
> git remote add linux-review https://github.com/intel-lab-lkp/linux
> git fetch --no-tags linux-review Tiezhu-Yang/LoongArch-Simulate-branch-and-PC-instructions/20230114-173012
> git checkout da766ea35a574bece74a5068aad708b5773b2981
> # save the config file
> mkdir build_dir && cp config build_dir/.config
> COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=loongarch olddefconfig
> COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=loongarch SHELL=/bin/bash arch/loongarch/kernel/
>
> If you fix the issue, kindly add following tag where applicable
> | Reported-by: kernel test robot <[email protected]>
>
> Note: functions only called from assembly code should be annotated with the asmlinkage attribute
> All warnings (new ones prefixed by >>):
>
>>> arch/loongarch/kernel/kprobes.c:376:14: warning: no previous prototype for 'trampoline_probe_handler' [-Wmissing-prototypes]
> 376 | void __used *trampoline_probe_handler(struct pt_regs *regs)
> | ^~~~~~~~~~~~~~~~~~~~~~~~
>
>
> vim +/trampoline_probe_handler +376 arch/loongarch/kernel/kprobes.c
>
> 374
> 375 /* Called from __kretprobe_trampoline */
> > 376 void __used *trampoline_probe_handler(struct pt_regs *regs)
> 377 {
> 378 return (void *)kretprobe_trampoline_handler(regs, NULL);
> 379 }
> 380 NOKPROBE_SYMBOL(trampoline_probe_handler);
> 381
>
Thanks for the report, I can reproduce it when make W=1
and also can silence it when declare the prototype
void *trampoline_probe_handler(struct pt_regs *regs);
in arch/loongarch/include/asm/kprobes.h
Let me wait for some time, if no more comments, I will
update this patch and then send v12.
Thanks,
Tiezhu