[PATCH v9 06/11] arm64: Make profile_pc() use arch_stack_walk()

madvenka
2021-10-15T02:35:21Z

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

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 <madvenka@linux.microsoft.com>
---
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;

- 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