[PATCH v4 39/57] oprofile/x86: convert x86_backtrace() to use the new unwinder

From: Josh Poimboeuf
Date: Thu Aug 18 2016 - 09:20:56 EST


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

Cc: Robert Richter <rric@xxxxxxxxxx>
Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
---
arch/x86/oprofile/backtrace.c | 39 +++++++++++++++++----------------------
1 file changed, 17 insertions(+), 22 deletions(-)

diff --git a/arch/x86/oprofile/backtrace.c b/arch/x86/oprofile/backtrace.c
index 7539148..f28ac1a 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, const 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 *
@@ -113,14 +93,29 @@ x86_backtrace(struct pt_regs * const regs, unsigned int depth)
struct stack_frame *head = (struct stack_frame *)frame_pointer(regs);

if (!user_mode(regs)) {
+ struct unwind_state state;
+ unsigned long addr;
+
if (!depth)
return;

oprofile_add_trace(regs->ip);
+
if (!--depth)
return;

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

--
2.7.4