[PATCH 14/19] oprofile/x86: convert x86_backtrace() to the new unwinder

From: Josh Poimboeuf
Date: Thu Jul 21 2016 - 17:23:09 EST


Convert oprofile's x86_backtrace() to the new unwinder. dump_trace()
has been deprecated.

Cc: Robert Richter <rric@xxxxxxxxxx>
Cc: oprofile-list@xxxxxxxxxxxx
Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
---
arch/x86/oprofile/backtrace.c | 42 +++++++++++++++++++-----------------------
1 file changed, 19 insertions(+), 23 deletions(-)

diff --git a/arch/x86/oprofile/backtrace.c b/arch/x86/oprofile/backtrace.c
index c594768..6cda1f4 100644
--- a/arch/x86/oprofile/backtrace.c
+++ b/arch/x86/oprofile/backtrace.c
@@ -16,27 +16,7 @@

#include <asm/ptrace.h>
#include <asm/stacktrace.h>
-
-static int backtrace_stack(void *data, char *name)
-{
- /* Yes, we want all stacks */
- return 0;
-}
-
-static int backtrace_address(void *data, unsigned long addr, int reliable)
-{
- unsigned int *depth = data;
-
- if ((*depth)--)
- oprofile_add_trace(addr);
- return 0;
-}
-
-static struct stacktrace_ops backtrace_ops = {
- .stack = backtrace_stack,
- .address = backtrace_address,
- .walk_stack = print_context_stack,
-};
+#include <asm/unwind.h>

#ifdef CONFIG_COMPAT
static struct stack_frame_ia32 *
@@ -113,8 +93,24 @@ x86_backtrace(struct pt_regs * const regs, unsigned int depth)
struct stack_frame *head = (struct stack_frame *)frame_pointer(regs);

if (!user_mode(regs)) {
- if (depth)
- dump_trace(NULL, regs, NULL, 0, &backtrace_ops, &depth);
+ struct unwind_state state;
+ unsigned long addr;
+
+ if (!depth)
+ return;
+
+ oprofile_add_trace(regs->ip);
+
+ if (!--depth)
+ return;
+
+ for (unwind_start(&state, NULL, regs, NULL);
+ !unwind_done(&state); unwind_next_frame(&state)) {
+ addr = unwind_get_return_address(&state);
+ oprofile_add_trace(addr);
+ if (!--depth)
+ break;
+ }
return;
}

--
2.7.4