[RFC 2/3] arm64: refactor save_stack_trace()
Jungseok Lee
jungseoklee85 at gmail.com
Fri Jul 17 08:34:21 PDT 2015
On Jul 17, 2015, at 11:59 PM, Jungseok Lee wrote:
> On Jul 17, 2015, at 11:41 PM, Steven Rostedt wrote:
>> On Fri, 17 Jul 2015 23:28:13 +0900
>> Jungseok Lee <jungseoklee85 at gmail.com> wrote:
>>
>>
>>>
>>> I have reviewed and tested the kernel including this patch and only [RFC 1/3].
>>
>> Thanks! Can you repost patch 1 with the changes I recommended, so that
>> I can get an Acked-by from the arm64 maintainers and pull all the
>> changes in together. This is fine for a 4.3 release, right? That is, it
>> doesn't need to go into 4.2-rcs.
>>
>
> Welcome!
>
> It's not hard to repost a patch, but I feel like we have to wait for Akashi's response.
> Also, it might be needed to consider Mark's comment on arch part.
>
> If they are okay, I will proceed.
Akashi and Mark,
The [RFC 1/3] patch used in my environment is shaped as follows.
I leave the hunk for *only* clear synchronization. This is why I choose this format
instead of reposting a patch. I hope it would help to track down this thread.
Steve,
I think this is my best at this point.
Best Regards
Jungseok Lee
----8<----
diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h
index c5534fa..2b43e20 100644
--- a/arch/arm64/include/asm/ftrace.h
+++ b/arch/arm64/include/asm/ftrace.h
@@ -13,8 +13,9 @@
#include <asm/insn.h>
-#define MCOUNT_ADDR ((unsigned long)_mcount)
-#define MCOUNT_INSN_SIZE AARCH64_INSN_SIZE
+#define MCOUNT_ADDR ((unsigned long)_mcount)
+#define MCOUNT_INSN_SIZE AARCH64_INSN_SIZE
+#define FTRACE_STACK_FRAME_OFFSET AARCH64_INSN_SIZE
#ifndef __ASSEMBLY__
#include <linux/compat.h>
diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
index 407991b..9ab67af 100644
--- a/arch/arm64/kernel/stacktrace.c
+++ b/arch/arm64/kernel/stacktrace.c
@@ -20,6 +20,7 @@
#include <linux/sched.h>
#include <linux/stacktrace.h>
+#include <asm/insn.h>
#include <asm/stacktrace.h>
/*
@@ -52,7 +53,7 @@ int notrace unwind_frame(struct stackframe *frame)
* -4 here because we care about the PC at time of bl,
* not where the return will go.
*/
- frame->pc = *(unsigned long *)(fp + 8) - 4;
+ frame->pc = *(unsigned long *)(fp + 8) - AARCH64_INSN_SIZE;
return 0;
}
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 1da6029..6566201 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -260,6 +260,9 @@ static inline void ftrace_kill(void) { }
#endif /* CONFIG_FUNCTION_TRACER */
#ifdef CONFIG_STACK_TRACER
+#ifndef FTRACE_STACK_FRAME_OFFSET
+#define FTRACE_STACK_FRAME_OFFSET 0
+#endif
extern int stack_tracer_enabled;
int
stack_trace_sysctl(struct ctl_table *table, int write,
diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c
index b746399..30521ea 100644
--- a/kernel/trace/trace_stack.c
+++ b/kernel/trace/trace_stack.c
@@ -105,7 +105,7 @@ check_stack(unsigned long ip, unsigned long *stack)
/* Skip over the overhead of the stack tracer itself */
for (i = 0; i < max_stack_trace.nr_entries; i++) {
- if (stack_dump_trace[i] == ip)
+ if ((stack_dump_trace[i] + FTRACE_STACK_FRAME_OFFSET) == ip)
break;
}
@@ -133,7 +133,8 @@ check_stack(unsigned long ip, unsigned long *stack)
for (; p < top && i < max_stack_trace.nr_entries; p++) {
if (stack_dump_trace[i] == ULONG_MAX)
break;
- if (*p == stack_dump_trace[i]) {
+ if (*p == (stack_dump_trace[i]
+ + FTRACE_STACK_FRAME_OFFSET)) {
stack_dump_trace[x] = stack_dump_trace[i++];
this_size = stack_dump_index[x++] =
(top - p) * sizeof(unsigned long);
----8<----
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