This series in order to add stacktrace support, Some upcoming features require
these changes, like trace, divide unwinder into guess unwinder and prologue
unwinder is to add new unwinders in the future.
eg:unwinder_frame, unwinder_orc .etc.
Three stages when we do unwind,
1) unwind_start(), the prapare of unwinding, fill unwind_state.
2) unwind_done(), judge whether the unwind process is finished or not.
3) unwind_next_frame(), unwind the next frame.
you can test them by:
1) echo t > /proc/sysrq-trigger
2) cat /proc/*/stack
3) ftrace: function graph
4) uprobe: echo 1 > ./options/userstacktrace
Changes from v1 to v2:
- Add the judgment of the offset value of ra in the prologue.
(Suggested by Youling).
- Create an inline function to check the sign bit, which is convenient
for extending other types of immediates. (Suggested by Jinyang).
- Fix sparse warning :
arch/loongarch/include/asm/uaccess.h:232:32: sparse: sparse: incorrect
type in argument 2 (different address spaces) @@ expected void const
*from @@ got void const [noderef] __user *from @@
- Add USER_STACKTRACE support as a series.
Changes from v2 to v3:
- Move unwind_start definition and use location, remove #ifdef in unwind_state
and use type instead of enable. (Suggested by Huacai).
- Separated fixes for uaccess.h. (Suggested by Huacai).
Changes from v3 to v4:
- Add get wchan implement. (Suggested by Huacai).
Qing Zhang (4):
LoongArch: Add guess unwinder support
LoongArch: Add prologue unwinder support
LoongArch: Add stacktrace and get_wchan support
LoongArch: Add USER_STACKTRACE support
arch/loongarch/Kconfig | 6 +
arch/loongarch/Kconfig.debug | 28 ++++
arch/loongarch/include/asm/inst.h | 52 +++++++
arch/loongarch/include/asm/processor.h | 9 ++
arch/loongarch/include/asm/stacktrace.h | 22 +++
arch/loongarch/include/asm/switch_to.h | 14 +-
arch/loongarch/include/asm/unwind.h | 47 +++++++
arch/loongarch/kernel/Makefile | 4 +
arch/loongarch/kernel/asm-offsets.c | 2 +
arch/loongarch/kernel/process.c | 91 ++++++++++++-
arch/loongarch/kernel/stacktrace.c | 78 +++++++++++
arch/loongarch/kernel/switch.S | 2 +
arch/loongarch/kernel/traps.c | 24 ++--
arch/loongarch/kernel/unwind_guess.c | 67 +++++++++
arch/loongarch/kernel/unwind_prologue.c | 173 ++++++++++++++++++++++++
15 files changed, 602 insertions(+), 17 deletions(-)
create mode 100644 arch/loongarch/include/asm/unwind.h
create mode 100644 arch/loongarch/kernel/stacktrace.c
create mode 100644 arch/loongarch/kernel/unwind_guess.c
create mode 100644 arch/loongarch/kernel/unwind_prologue.c
--
2.20.1
1. Use common arch_stack_walk infrastructure to avoid duplicated code and
avoid taking care of the stack storage and filtering.
2. Add sra (means sched return address) and scfa (means sched call
frame address) to thread_info and store it in switch_to().
3. Add get wchan implement.
Now we can print the process stack and wait channel by cat /proc/*/stack
and /proc/*/wchan.
Signed-off-by: Qing Zhang <[email protected]>
---
arch/loongarch/Kconfig | 5 ++++
arch/loongarch/include/asm/processor.h | 9 +++++++
arch/loongarch/include/asm/switch_to.h | 14 ++++++----
arch/loongarch/kernel/Makefile | 1 +
arch/loongarch/kernel/asm-offsets.c | 2 ++
arch/loongarch/kernel/process.c | 30 ++++++++++++++++++++-
arch/loongarch/kernel/stacktrace.c | 37 ++++++++++++++++++++++++++
arch/loongarch/kernel/switch.S | 2 ++
8 files changed, 94 insertions(+), 6 deletions(-)
create mode 100644 arch/loongarch/kernel/stacktrace.c
diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
index fc2465892a60..8143774f99cb 100644
--- a/arch/loongarch/Kconfig
+++ b/arch/loongarch/Kconfig
@@ -39,6 +39,7 @@ config LOONGARCH
select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE if !PREEMPTION
select ARCH_MIGHT_HAVE_PC_PARPORT
select ARCH_MIGHT_HAVE_PC_SERIO
+ select ARCH_STACKWALK
select ARCH_SPARSEMEM_ENABLE
select ARCH_SUPPORTS_ACPI
select ARCH_SUPPORTS_ATOMIC_RMW
@@ -141,6 +142,10 @@ config LOCKDEP_SUPPORT
bool
default y
+config STACKTRACE_SUPPORT
+ bool
+ default y
+
# MACH_LOONGSON32 and MACH_LOONGSON64 are delibrately carried over from the
# MIPS Loongson code, to preserve Loongson-specific code paths in drivers that
# are shared between architectures, and specifically expecting the symbols.
diff --git a/arch/loongarch/include/asm/processor.h b/arch/loongarch/include/asm/processor.h
index 57ec45aa078e..1c4b4308378d 100644
--- a/arch/loongarch/include/asm/processor.h
+++ b/arch/loongarch/include/asm/processor.h
@@ -101,6 +101,10 @@ struct thread_struct {
unsigned long reg23, reg24, reg25, reg26; /* s0-s3 */
unsigned long reg27, reg28, reg29, reg30, reg31; /* s4-s8 */
+ /* __schedule() return address / call frame address */
+ unsigned long sched_ra;
+ unsigned long sched_cfa;
+
/* CSR registers */
unsigned long csr_prmd;
unsigned long csr_crmd;
@@ -129,6 +133,9 @@ struct thread_struct {
struct loongarch_fpu fpu FPU_ALIGN;
};
+#define thread_saved_ra(tsk) (tsk->thread.sched_ra)
+#define thread_saved_fp(tsk) (tsk->thread.sched_cfa)
+
#define INIT_THREAD { \
/* \
* Main processor registers \
@@ -145,6 +152,8 @@ struct thread_struct {
.reg29 = 0, \
.reg30 = 0, \
.reg31 = 0, \
+ .sched_ra = 0, \
+ .sched_cfa = 0, \
.csr_crmd = 0, \
.csr_prmd = 0, \
.csr_euen = 0, \
diff --git a/arch/loongarch/include/asm/switch_to.h b/arch/loongarch/include/asm/switch_to.h
index 2a8d04375574..43a5ab162d38 100644
--- a/arch/loongarch/include/asm/switch_to.h
+++ b/arch/loongarch/include/asm/switch_to.h
@@ -15,12 +15,15 @@ struct task_struct;
* @prev: The task previously executed.
* @next: The task to begin executing.
* @next_ti: task_thread_info(next).
+ * @sched_ra: __schedule return address.
+ * @sched_cfa: __schedule call frame address.
*
* This function is used whilst scheduling to save the context of prev & load
* the context of next. Returns prev.
*/
extern asmlinkage struct task_struct *__switch_to(struct task_struct *prev,
- struct task_struct *next, struct thread_info *next_ti);
+ struct task_struct *next, struct thread_info *next_ti,
+ void *sched_ra, void *sched_cfa);
/*
* For newly created kernel threads switch_to() will return to
@@ -28,10 +31,11 @@ extern asmlinkage struct task_struct *__switch_to(struct task_struct *prev,
* That is, everything following __switch_to() will be skipped for new threads.
* So everything that matters to new threads should be placed before __switch_to().
*/
-#define switch_to(prev, next, last) \
-do { \
- lose_fpu_inatomic(1, prev); \
- (last) = __switch_to(prev, next, task_thread_info(next)); \
+#define switch_to(prev, next, last) \
+do { \
+ lose_fpu_inatomic(1, prev); \
+ (last) = __switch_to(prev, next, task_thread_info(next), \
+ __builtin_return_address(0), __builtin_frame_address(0)); \
} while (0)
#endif /* _ASM_SWITCH_TO_H */
diff --git a/arch/loongarch/kernel/Makefile b/arch/loongarch/kernel/Makefile
index 918600e7b30f..7449513eb08d 100644
--- a/arch/loongarch/kernel/Makefile
+++ b/arch/loongarch/kernel/Makefile
@@ -15,6 +15,7 @@ obj-$(CONFIG_EFI) += efi.o
obj-$(CONFIG_CPU_HAS_FPU) += fpu.o
obj-$(CONFIG_MODULES) += module.o module-sections.o
+obj-$(CONFIG_STACKTRACE) += stacktrace.o
obj-$(CONFIG_PROC_FS) += proc.o
diff --git a/arch/loongarch/kernel/asm-offsets.c b/arch/loongarch/kernel/asm-offsets.c
index 20cd9e16a95a..eb350f3ffae5 100644
--- a/arch/loongarch/kernel/asm-offsets.c
+++ b/arch/loongarch/kernel/asm-offsets.c
@@ -103,6 +103,8 @@ void output_thread_defines(void)
OFFSET(THREAD_REG29, task_struct, thread.reg29);
OFFSET(THREAD_REG30, task_struct, thread.reg30);
OFFSET(THREAD_REG31, task_struct, thread.reg31);
+ OFFSET(THREAD_SCHED_RA, task_struct, thread.sched_ra);
+ OFFSET(THREAD_SCHED_CFA, task_struct, thread.sched_cfa);
OFFSET(THREAD_CSRCRMD, task_struct,
thread.csr_crmd);
OFFSET(THREAD_CSRPRMD, task_struct,
diff --git a/arch/loongarch/kernel/process.c b/arch/loongarch/kernel/process.c
index 709b7a1664f8..d9dba725ef02 100644
--- a/arch/loongarch/kernel/process.c
+++ b/arch/loongarch/kernel/process.c
@@ -135,6 +135,7 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
childregs = (struct pt_regs *) childksp - 1;
/* Put the stack after the struct pt_regs. */
childksp = (unsigned long) childregs;
+ p->thread.sched_cfa = 0;
p->thread.csr_euen = 0;
p->thread.csr_crmd = csr_read32(LOONGARCH_CSR_CRMD);
p->thread.csr_prmd = csr_read32(LOONGARCH_CSR_PRMD);
@@ -145,6 +146,7 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
p->thread.reg23 = (unsigned long)args->fn;
p->thread.reg24 = (unsigned long)args->fn_arg;
p->thread.reg01 = (unsigned long)ret_from_kernel_thread;
+ p->thread.sched_ra = (unsigned long)ret_from_kernel_thread;
memset(childregs, 0, sizeof(struct pt_regs));
childregs->csr_euen = p->thread.csr_euen;
childregs->csr_crmd = p->thread.csr_crmd;
@@ -161,6 +163,7 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
p->thread.reg03 = (unsigned long) childregs;
p->thread.reg01 = (unsigned long) ret_from_fork;
+ p->thread.sched_ra = (unsigned long) ret_from_fork;
/*
* New tasks lose permission to use the fpu. This accelerates context
@@ -181,9 +184,34 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
unsigned long __get_wchan(struct task_struct *task)
{
- return 0;
+ unsigned long pc;
+ struct unwind_state state;
+
+ if (!try_get_task_stack(task))
+ return 0;
+
+ unwind_start(&state, task, NULL);
+ state.sp = thread_saved_fp(task);
+ get_stack_info(state.sp, state.task, &state.stack_info);
+ state.pc = thread_saved_ra(task);
+#ifdef CONFIG_UNWINDER_PROLOGUE
+ state.type = UNWINDER_PROLOGUE;
+#endif
+ for ( ; !unwind_done(&state); unwind_next_frame(&state)) {
+ pc = unwind_get_return_address(&state);
+ if (!pc)
+ break;
+ if (in_sched_functions(pc))
+ continue;
+ break;
+ }
+
+ put_task_stack(task);
+
+ return pc;
}
+
bool in_task_stack(unsigned long stack, struct task_struct *task,
struct stack_info *info)
{
diff --git a/arch/loongarch/kernel/stacktrace.c b/arch/loongarch/kernel/stacktrace.c
new file mode 100644
index 000000000000..f4f4b8ad3917
--- /dev/null
+++ b/arch/loongarch/kernel/stacktrace.c
@@ -0,0 +1,37 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Stack trace management functions
+ *
+ * Copyright (C) 2022 Loongson Technology Corporation Limited
+ */
+#include <linux/sched.h>
+#include <linux/stacktrace.h>
+
+#include <asm/stacktrace.h>
+#include <asm/unwind.h>
+
+void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie,
+ struct task_struct *task, struct pt_regs *regs)
+{
+ struct pt_regs dummyregs;
+ struct unwind_state state;
+ unsigned long addr;
+
+ regs = &dummyregs;
+
+ if (task == current) {
+ regs->csr_era = (unsigned long)__builtin_return_address(0);
+ regs->regs[3] = (unsigned long)__builtin_frame_address(0);
+ } else {
+ regs->csr_era = thread_saved_ra(task);
+ regs->regs[3] = thread_saved_fp(task);
+ }
+
+ regs->regs[1] = 0;
+ for (unwind_start(&state, task, regs);
+ !unwind_done(&state); unwind_next_frame(&state)) {
+ addr = unwind_get_return_address(&state);
+ if (!addr || !consume_entry(cookie, addr))
+ break;
+ }
+}
diff --git a/arch/loongarch/kernel/switch.S b/arch/loongarch/kernel/switch.S
index 37e84ac8ffc2..43ebbc3990f7 100644
--- a/arch/loongarch/kernel/switch.S
+++ b/arch/loongarch/kernel/switch.S
@@ -21,6 +21,8 @@ SYM_FUNC_START(__switch_to)
cpu_save_nonscratch a0
stptr.d ra, a0, THREAD_REG01
+ stptr.d a3, a0, THREAD_SCHED_RA
+ stptr.d a4, a0, THREAD_SCHED_CFA
move tp, a2
cpu_restore_nonscratch a1
--
2.20.1
Queued for 5.20,thanks.
Huacai
On Sat, Aug 6, 2022 at 4:10 PM Qing Zhang <[email protected]> wrote:
>
> This series in order to add stacktrace support, Some upcoming features require
> these changes, like trace, divide unwinder into guess unwinder and prologue
> unwinder is to add new unwinders in the future.
> eg:unwinder_frame, unwinder_orc .etc.
>
> Three stages when we do unwind,
> 1) unwind_start(), the prapare of unwinding, fill unwind_state.
> 2) unwind_done(), judge whether the unwind process is finished or not.
> 3) unwind_next_frame(), unwind the next frame.
>
> you can test them by:
> 1) echo t > /proc/sysrq-trigger
> 2) cat /proc/*/stack
> 3) ftrace: function graph
> 4) uprobe: echo 1 > ./options/userstacktrace
>
> Changes from v1 to v2:
>
> - Add the judgment of the offset value of ra in the prologue.
> (Suggested by Youling).
> - Create an inline function to check the sign bit, which is convenient
> for extending other types of immediates. (Suggested by Jinyang).
> - Fix sparse warning :
> arch/loongarch/include/asm/uaccess.h:232:32: sparse: sparse: incorrect
> type in argument 2 (different address spaces) @@ expected void const
> *from @@ got void const [noderef] __user *from @@
> - Add USER_STACKTRACE support as a series.
>
> Changes from v2 to v3:
>
> - Move unwind_start definition and use location, remove #ifdef in unwind_state
> and use type instead of enable. (Suggested by Huacai).
> - Separated fixes for uaccess.h. (Suggested by Huacai).
>
> Changes from v3 to v4:
>
> - Add get wchan implement. (Suggested by Huacai).
>
> Qing Zhang (4):
> LoongArch: Add guess unwinder support
> LoongArch: Add prologue unwinder support
> LoongArch: Add stacktrace and get_wchan support
> LoongArch: Add USER_STACKTRACE support
>
> arch/loongarch/Kconfig | 6 +
> arch/loongarch/Kconfig.debug | 28 ++++
> arch/loongarch/include/asm/inst.h | 52 +++++++
> arch/loongarch/include/asm/processor.h | 9 ++
> arch/loongarch/include/asm/stacktrace.h | 22 +++
> arch/loongarch/include/asm/switch_to.h | 14 +-
> arch/loongarch/include/asm/unwind.h | 47 +++++++
> arch/loongarch/kernel/Makefile | 4 +
> arch/loongarch/kernel/asm-offsets.c | 2 +
> arch/loongarch/kernel/process.c | 91 ++++++++++++-
> arch/loongarch/kernel/stacktrace.c | 78 +++++++++++
> arch/loongarch/kernel/switch.S | 2 +
> arch/loongarch/kernel/traps.c | 24 ++--
> arch/loongarch/kernel/unwind_guess.c | 67 +++++++++
> arch/loongarch/kernel/unwind_prologue.c | 173 ++++++++++++++++++++++++
> 15 files changed, 602 insertions(+), 17 deletions(-)
> create mode 100644 arch/loongarch/include/asm/unwind.h
> create mode 100644 arch/loongarch/kernel/stacktrace.c
> create mode 100644 arch/loongarch/kernel/unwind_guess.c
> create mode 100644 arch/loongarch/kernel/unwind_prologue.c
>
> --
> 2.20.1
>