[PATCH v10 05/11] arm64: Make dump_stacktrace() use arch_stack_walk()

madvenka
2021-10-15T02:59:29Z

From: "Madhavan T. Venkataraman" <madvenka@linux.microsoft.com>

Currently, dump_stacktrace() in ARM64 code walks the stack using
start_backtrace() and unwind_frame(). Make it use arch_stack_walk()
instead. This makes maintenance easier.

Signed-off-by: Madhavan T. Venkataraman <madvenka@linux.microsoft.com>
---
arch/arm64/kernel/stacktrace.c | 44 +++++-----------------------------
1 file changed, 6 insertions(+), 38 deletions(-)

diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
index 8982a2b78acf..776c4debb5a7 100644
--- a/arch/arm64/kernel/stacktrace.c
+++ b/arch/arm64/kernel/stacktrace.c
@@ -151,24 +151,20 @@ void notrace walk_stackframe(struct task_struct *tsk, struct stackframe *frame,
}
NOKPROBE_SYMBOL(walk_stackframe);

-static void dump_backtrace_entry(unsigned long where, const char *loglvl)
+static bool dump_backtrace_entry(void *arg, unsigned long where)
{
+ char *loglvl = arg;
printk("%s %pSb\n", loglvl, (void *)where);
+ return true;
}

void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
const char *loglvl)
{
- struct stackframe frame;
- int skip = 0;
-
pr_debug("%s(regs = %p tsk = %p)\n", __func__, regs, tsk);

- if (regs) {
- if (user_mode(regs))
- return;
- skip = 1;
- }
+ if (regs && user_mode(regs))
+ return;

if (!tsk)
tsk = current;
@@ -176,36 +172,8 @@ void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
if (!try_get_task_stack(tsk))
return;

- if (tsk == current) {
- start_backtrace(&frame,
- (unsigned long)__builtin_frame_address(0),
- (unsigned long)dump_backtrace);
- } else {
- /*
- * task blocked in __switch_to
- */
- start_backtrace(&frame,
- thread_saved_fp(tsk),
- thread_saved_pc(tsk));
- }
-
printk("%sCall trace:\n", loglvl);
- do {
- /* skip until specified stack frame */
- if (!skip) {
- dump_backtrace_entry(frame.pc, loglvl);
- } else if (frame.fp == regs->regs[29]) {
- skip = 0;
- /*
- * Mostly, this is the case where this function is
- * called in panic/abort. As exception handler's
- * stack frame does not contain the corresponding pc
- * at which an exception has taken place, use regs->pc
- * instead.
- */
- dump_backtrace_entry(regs->pc, loglvl);
- }
- } while (!unwind_frame(tsk, &frame));
+ arch_stack_walk(dump_backtrace_entry, (void *)loglvl, tsk, regs);

put_task_stack(tsk);
}
--
2.25.1