[PATCH v9 02/11] arm64: Make perf_callchain_kernel() use arch_stack_walk()

madvenka
2021-10-15T02:35:04Z

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

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

Signed-off-by: Madhavan T. Venkataraman <madvenka@linux.microsoft.com>
---
arch/arm64/kernel/perf_callchain.c | 8 ++------
1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/arch/arm64/kernel/perf_callchain.c b/arch/arm64/kernel/perf_callchain.c
index 4a72c2727309..f173c448e852 100644
--- a/arch/arm64/kernel/perf_callchain.c
+++ b/arch/arm64/kernel/perf_callchain.c
@@ -140,22 +140,18 @@ void perf_callchain_user(struct perf_callchain_entry_ctx *entry,
static bool callchain_trace(void *data, unsigned long pc)
{
struct perf_callchain_entry_ctx *entry = data;
- perf_callchain_store(entry, pc);
- return true;
+ return perf_callchain_store(entry, pc) == 0;
}

void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry,
struct pt_regs *regs)
{
- struct stackframe frame;
-
if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) {
/* We don't support guest os callchain now */
return;
}

- start_backtrace(&frame, regs->regs[29], regs->pc);
- walk_stackframe(current, &frame, callchain_trace, entry);
+ arch_stack_walk(callchain_trace, entry, current, regs);
}

unsigned long perf_instruction_pointer(struct pt_regs *regs)
--
2.25.1