Re: [PATCH v10 06/11] arm64: Make profile_pc() use arch_stack_walk()
From: Mark Rutland <mark.rutland@arm.com>
Date: 2021-10-27 13:32:21
Also in:
linux-arm-kernel, lkml
On Thu, Oct 14, 2021 at 09:58:42PM -0500, madvenka@linux.microsoft.com wrote:
quoted hunk ↗ jump to hunk
From: "Madhavan T. Venkataraman" <redacted> Currently, profile_pc() 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 <redacted> --- arch/arm64/kernel/time.c | 22 +++++++++++++--------- 1 file changed, 13 insertions(+), 9 deletions(-)diff --git a/arch/arm64/kernel/time.c b/arch/arm64/kernel/time.c index eebbc8d7123e..671b3038a772 100644 --- a/arch/arm64/kernel/time.c +++ b/arch/arm64/kernel/time.c@@ -32,22 +32,26 @@ #include <asm/stacktrace.h> #include <asm/paravirt.h> +static bool profile_pc_cb(void *arg, unsigned long pc) +{ + unsigned long *prof_pc = arg; + + if (in_lock_functions(pc)) + return true; + *prof_pc = pc; + return false; +} + unsigned long profile_pc(struct pt_regs *regs) { - struct stackframe frame; + unsigned long prof_pc = 0; if (!in_lock_functions(regs->pc)) return regs->pc;
This can go -- the first call to profile_pc_cb() will use regs->pc. With that gone, and the include updates to use <linux/stacktrace.h>: Reviewed-by: Mark Rutland <mark.rutland@arm.com> Mark.
- start_backtrace(&frame, regs->regs[29], regs->pc);
-
- do {
- int ret = unwind_frame(NULL, &frame);
- if (ret < 0)
- return 0;
- } while (in_lock_functions(frame.pc));
+ arch_stack_walk(profile_pc_cb, &prof_pc, current, regs);
- return frame.pc;
+ return prof_pc;
}
EXPORT_SYMBOL(profile_pc);
--
2.25.1