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Date: Tue, 20 Sep 2022 23:11:57 +0800
From: Chen Zhongjin <chenzhongjin@...wei.com>
To: <linux-kernel@...r.kernel.org>, <linux-riscv@...ts.infradead.org>,
<linux-perf-users@...r.kernel.org>
CC: <paul.walmsley@...ive.com>, <palmer@...belt.com>,
<aou@...s.berkeley.edu>, <peterz@...radead.org>,
<mingo@...hat.com>, <acme@...nel.org>, <mark.rutland@....com>,
<alexander.shishkin@...ux.intel.com>, <namhyung@...nel.org>,
<jolsa@...nel.org>, <guoren@...nel.org>, <nsaenzju@...hat.com>,
<frederic@...nel.org>, <changbin.du@...el.com>,
<vincent.chen@...ive.com>, <ardb@...nel.org>,
<mhiramat@...nel.org>, <rostedt@...dmis.org>,
<keescook@...omium.org>, <catalin.marinas@....com>,
<chenzhongjin@...wei.com>
Subject: [PATCH -next 2/7] riscv: stacktrace: Introduce unwind functions
Now all riscv unwinding code is inside arch_stack_walk. It's
not same as other architectures.
Make some refactoring, to move unwinding code into unwind() and
unwind_next() functions, which walks through all stack frames
or single frame.
This patch only moves code but doesn't make any logical change.
Signed-off-by: Chen Zhongjin <chenzhongjin@...wei.com>
---
arch/riscv/include/asm/stacktrace.h | 7 ++
arch/riscv/kernel/stacktrace.c | 104 ++++++++++++++++++----------
2 files changed, 74 insertions(+), 37 deletions(-)
diff --git a/arch/riscv/include/asm/stacktrace.h b/arch/riscv/include/asm/stacktrace.h
index b6cd3eddfd38..a39e4ef1dbd5 100644
--- a/arch/riscv/include/asm/stacktrace.h
+++ b/arch/riscv/include/asm/stacktrace.h
@@ -11,6 +11,13 @@ struct stackframe {
unsigned long ra;
};
+struct unwind_state {
+ unsigned long fp;
+ unsigned long sp;
+ unsigned long pc;
+ struct pt_regs *regs;
+};
+
extern void dump_backtrace(struct pt_regs *regs, struct task_struct *task,
const char *loglvl);
diff --git a/arch/riscv/kernel/stacktrace.c b/arch/riscv/kernel/stacktrace.c
index b51e32d50a0e..e84e21868a3e 100644
--- a/arch/riscv/kernel/stacktrace.c
+++ b/arch/riscv/kernel/stacktrace.c
@@ -16,54 +16,84 @@
#ifdef CONFIG_FRAME_POINTER
-noinline notrace void arch_stack_walk(stack_trace_consume_fn consume_entry,
- void *cookie, struct task_struct *task,
- struct pt_regs *regs)
+static int notrace unwind_next(struct unwind_state *state)
{
- unsigned long fp, sp, pc;
- int level = 0;
+ unsigned long low, high, fp;
+ struct stackframe *frame;
- if (regs) {
- fp = frame_pointer(regs);
- sp = user_stack_pointer(regs);
- pc = instruction_pointer(regs);
- } else if (task == NULL || task == current) {
- fp = (unsigned long)__builtin_frame_address(0);
- sp = current_stack_pointer;
- pc = (unsigned long)arch_stack_walk;
+ fp = state->fp;
+
+ /* Validate frame pointer */
+ low = state->sp + sizeof(struct stackframe);
+ high = ALIGN(low, THREAD_SIZE);
+
+ if (fp < low || fp > high || fp & 0x7)
+ return -EINVAL;
+
+ /* Unwind stack frame */
+ frame = (struct stackframe *)fp - 1;
+ state->sp = fp;
+
+ if (state->regs && state->regs->epc == state->pc &&
+ fp & 0x7) {
+ state->fp = frame->ra;
+ state->pc = state->regs->ra;
} else {
- /* task blocked in __switch_to */
- fp = task->thread.s[0];
- sp = task->thread.sp;
- pc = task->thread.ra;
+ state->fp = frame->fp;
+ state->pc = ftrace_graph_ret_addr(current, NULL, frame->ra,
+ (unsigned long *)fp - 1);
}
- for (;;) {
- unsigned long low, high;
- struct stackframe *frame;
+ return 0;
+}
- if (unlikely(!__kernel_text_address(pc) ||
- (level++ >= 1 && !consume_entry(cookie, pc))))
+static void notrace unwind(struct unwind_state *state,
+ stack_trace_consume_fn consume_entry, void *cookie)
+{
+ while (1) {
+ int ret;
+
+ if (!__kernel_text_address(state->pc))
+ break;
+
+ if (!consume_entry(cookie, state->pc))
break;
- /* Validate frame pointer */
- low = sp + sizeof(struct stackframe);
- high = ALIGN(sp, THREAD_SIZE);
- if (unlikely(fp < low || fp > high || fp & 0x7))
+ ret = unwind_next(state);
+ if (ret < 0)
break;
- /* Unwind stack frame */
- frame = (struct stackframe *)fp - 1;
- sp = fp;
- if (regs && (regs->epc == pc) && (frame->fp & 0x7)) {
- fp = frame->ra;
- pc = regs->ra;
- } else {
- fp = frame->fp;
- pc = ftrace_graph_ret_addr(current, NULL, frame->ra,
- (unsigned long *)(fp - 8));
- }
+ }
+}
+
+noinline notrace void arch_stack_walk(stack_trace_consume_fn consume_entry,
+ void *cookie, struct task_struct *task,
+ struct pt_regs *regs)
+{
+ struct unwind_state state;
+
+ if (task == NULL)
+ task = current;
+ if (regs) {
+ state.fp = frame_pointer(regs);
+ state.sp = user_stack_pointer(regs);
+ state.pc = instruction_pointer(regs);
+ state.regs = regs;
+ } else if (task == current) {
+ state.fp = (unsigned long)__builtin_frame_address(0);
+ state.sp = current_stack_pointer;
+ state.pc = (unsigned long)arch_stack_walk;
+
+ /* skip frame of arch_stack_walk */
+ unwind_next(&state);
+ } else {
+ /* task blocked in __switch_to */
+ state.fp = task->thread.s[0];
+ state.sp = task->thread.sp;
+ state.pc = task->thread.ra;
}
+
+ unwind(&state, consume_entry, cookie);
}
#else /* !CONFIG_FRAME_POINTER */
--
2.17.1
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