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arm64: pass a task parameter to unwind_frame()

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Function graph tracer modifies a return address (LR) in a stack frame
to hook a function's return. This will result in many useless entries
(return_to_handler) showing up in a call stack list.
We will fix this problem in a later patch ("arm64: ftrace: fix a stack
tracer's output under function graph tracer"). But since real return
addresses are saved in ret_stack[] array in struct task_struct,
unwind functions need to be notified of, in addition to a stack pointer
address, which task is being traced in order to find out real return
addresses.

This patch extends unwind functions' interfaces by adding an extra
argument of a pointer to task_struct.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
This commit is contained in:
AKASHI Takahiro
2015-12-15 17:33:40 +09:00
committed by Will Deacon
parent 79fdee9b63
commit fe13f95b72
7 changed files with 13 additions and 11 deletions
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8
arch/arm64/kernel/stacktrace.c
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@@ -36,7 +36,7 @@
* ldp x29, x30, [sp]
* add sp, sp, #0x10
*/
int notrace unwind_frame(struct stackframe *frame)
int notrace unwind_frame(struct task_struct *tsk, struct stackframe *frame)
{
unsigned long high, low;
unsigned long fp = frame->fp;
@@ -99,7 +99,7 @@ int notrace unwind_frame(struct stackframe *frame)
return 0;
}
void notrace walk_stackframe(struct stackframe *frame,
void notrace walk_stackframe(struct task_struct *tsk, struct stackframe *frame,
int (*fn)(struct stackframe *, void *), void *data)
{
while (1) {
@@ -107,7 +107,7 @@ void notrace walk_stackframe(struct stackframe *frame,
if (fn(frame, data))
break;
ret = unwind_frame(frame);
ret = unwind_frame(tsk, frame);
if (ret < 0)
break;
}
@@ -159,7 +159,7 @@ void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
frame.pc = (unsigned long)save_stack_trace_tsk;
}
walk_stackframe(&frame, save_trace, &data);
walk_stackframe(tsk, &frame, save_trace, &data);
if (trace->nr_entries < trace->max_entries)
trace->entries[trace->nr_entries++] = ULONG_MAX;
}