perf events, x86/stacktrace: Make stack walking optional

The current print_context_stack helper that does the stack
walking job is good for usual stacktraces as it walks through
all the stack and reports even addresses that look unreliable,
which is nice when we don't have frame pointers for example.

But we have users like perf that only require reliable
stacktraces, and those may want a more adapted stack walker, so
lets make this function a callback in stacktrace_ops that users
can tune for their needs.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1261024834-5336-1-git-send-regression-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 10 insertions, 8 deletions

diff --git a/arch/x86/kernel/stacktrace.c b/arch/x86/kernel/stacktrace.c
index c3eb207181fe..922eefbb3f6c 100644
--- a/arch/x86/kernel/stacktrace.c
+++ b/arch/x86/kernel/stacktrace.c
@@ -53,17 +53,19 @@ save_stack_address_nosched(void *data, unsigned long addr, int reliable)
 }
 
 static const struct stacktrace_ops save_stack_ops = {
-        .warning = save_stack_warning,
-        .warning_symbol = save_stack_warning_symbol,
-        .stack = save_stack_stack,
-        .address = save_stack_address,
+        .warning        = save_stack_warning,
+        .warning_symbol = save_stack_warning_symbol,
+        .stack          = save_stack_stack,
+        .address        = save_stack_address,
+        .walk_stack     = print_context_stack,
 };
 
 static const struct stacktrace_ops save_stack_ops_nosched = {
-        .warning = save_stack_warning,
-        .warning_symbol = save_stack_warning_symbol,
-        .stack = save_stack_stack,
-        .address = save_stack_address_nosched,
+        .warning        = save_stack_warning,
+        .warning_symbol = save_stack_warning_symbol,
+        .stack          = save_stack_stack,
+        .address        = save_stack_address_nosched,
+        .walk_stack     = print_context_stack,
 };
 
 /*