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Commit 2d7c11bf authored by Catalin Marinas's avatar Catalin Marinas Committed by Russell King
Browse files

[ARM] 5382/1: unwind: Reorganise the stacktrace support 



This patch changes the walk_stacktrace and its callers for easier
integration of stack unwinding. The arch/arm/kernel/stacktrace.h file is
also moved to arch/arm/include/asm/stacktrace.h.

Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent 67a94c23

arch/arm/include/asm/stacktrace.h

0 → 100644
+15 −0
Original line number Diff line number Diff line 
#ifndef __ASM_STACKTRACE_H

#define __ASM_STACKTRACE_H



struct stackframe {

	unsigned long fp;

	unsigned long sp;

	unsigned long lr;

	unsigned long pc;

};



extern int unwind_frame(struct stackframe *frame);

extern void walk_stackframe(struct stackframe *frame,

			    int (*fn)(struct stackframe *, void *), void *data);



#endif	/* __ASM_STACKTRACE_H */

arch/arm/include/asm/thread_info.h

+2 −0
Original line number Diff line number Diff line
@@ -99,6 +99,8 @@ static inline struct thread_info *current_thread_info(void) 


#define thread_saved_pc(tsk)	\

	((unsigned long)(task_thread_info(tsk)->cpu_context.pc))

#define thread_saved_sp(tsk)	\

	((unsigned long)(task_thread_info(tsk)->cpu_context.sp))

#define thread_saved_fp(tsk)	\

	((unsigned long)(task_thread_info(tsk)->cpu_context.fp))

arch/arm/kernel/process.c

+10 −11
Original line number Diff line number Diff line
@@ -34,6 +34,7 @@ 
#include <asm/processor.h>

#include <asm/system.h>

#include <asm/thread_notify.h>

#include <asm/stacktrace.h>

#include <asm/mach/time.h>



static const char *processor_modes[] = {
@@ -372,23 +373,21 @@ EXPORT_SYMBOL(kernel_thread); 


unsigned long get_wchan(struct task_struct *p)

{

	unsigned long fp, lr;

	unsigned long stack_start, stack_end;

	struct stackframe frame;

	int count = 0;

	if (!p || p == current || p->state == TASK_RUNNING)

		return 0;



	stack_start = (unsigned long)end_of_stack(p);

	stack_end = (unsigned long)task_stack_page(p) + THREAD_SIZE;



	fp = thread_saved_fp(p);

	frame.fp = thread_saved_fp(p);

	frame.sp = thread_saved_sp(p);

	frame.lr = 0;			/* recovered from the stack */

	frame.pc = thread_saved_pc(p);

	do {

		if (fp < stack_start || fp > stack_end)

		int ret = unwind_frame(&frame);

		if (ret < 0)

			return 0;

		lr = ((unsigned long *)fp)[-1];

		if (!in_sched_functions(lr))

			return lr;

		fp = *(unsigned long *) (fp - 12);

		if (!in_sched_functions(frame.pc))

			return frame.pc;

	} while (count ++ < 16);

	return 0;

}

arch/arm/kernel/stacktrace.c

+60 −28
Original line number Diff line number Diff line
@@ -2,35 +2,60 @@ 
#include <linux/sched.h>

#include <linux/stacktrace.h>



#include "stacktrace.h"

#include <asm/stacktrace.h>



int walk_stackframe(unsigned long fp, unsigned long low, unsigned long high,

		    int (*fn)(struct stackframe *, void *), void *data)

{

	struct stackframe *frame;



	do {

#if defined(CONFIG_FRAME_POINTER) && !defined(CONFIG_ARM_UNWIND)

/*

		 * Check current frame pointer is within bounds

 * Unwind the current stack frame and store the new register values in the

 * structure passed as argument. Unwinding is equivalent to a function return,

 * hence the new PC value rather than LR should be used for backtrace.

 *

 * With framepointer enabled, a simple function prologue looks like this:

 *	mov	ip, sp

 *	stmdb	sp!, {fp, ip, lr, pc}

 *	sub	fp, ip, #4

 *

 * A simple function epilogue looks like this:

 *	ldm	sp, {fp, sp, pc}

 *

 * Note that with framepointer enabled, even the leaf functions have the same

 * prologue and epilogue, therefore we can ignore the LR value in this case.

 */

		if (fp < (low + 12) || fp + 4 >= high)

			break;

int unwind_frame(struct stackframe *frame)

{

	unsigned long high, low;

	unsigned long fp = frame->fp;



		frame = (struct stackframe *)(fp - 12);

	/* only go to a higher address on the stack */

	low = frame->sp;

	high = ALIGN(low, THREAD_SIZE) + THREAD_SIZE;



		if (fn(frame, data))

			break;

	/* check current frame pointer is within bounds */

	if (fp < (low + 12) || fp + 4 >= high)

		return -EINVAL;



		/*

		 * Update the low bound - the next frame must always

		 * be at a higher address than the current frame.

		 */

		low = fp + 4;

		fp = frame->fp;

	} while (fp);

	/* restore the registers from the stack frame */

	frame->fp = *(unsigned long *)(fp - 12);

	frame->sp = *(unsigned long *)(fp - 8);

	frame->pc = *(unsigned long *)(fp - 4);



	return 0;

}

#endif



void walk_stackframe(struct stackframe *frame,

		     int (*fn)(struct stackframe *, void *), void *data)

{

	while (1) {

		int ret;



		if (fn(frame, data))

			break;

		ret = unwind_frame(frame);

		if (ret < 0)

			break;

	}

}

EXPORT_SYMBOL(walk_stackframe);



#ifdef CONFIG_STACKTRACE
@@ -44,7 +69,7 @@ static int save_trace(struct stackframe *frame, void *d) 
{

	struct stack_trace_data *data = d;

	struct stack_trace *trace = data->trace;

	unsigned long addr = frame->lr;

	unsigned long addr = frame->pc;



	if (data->no_sched_functions && in_sched_functions(addr))

		return 0;
@@ -61,11 +86,10 @@ static int save_trace(struct stackframe *frame, void *d) 
void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)

{

	struct stack_trace_data data;

	unsigned long fp, base;

	struct stackframe frame;



	data.trace = trace;

	data.skip = trace->skip;

	base = (unsigned long)task_stack_page(tsk);



	if (tsk != current) {

#ifdef CONFIG_SMP
@@ -76,14 +100,22 @@ void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace) 
		BUG();

#else

		data.no_sched_functions = 1;

		fp = thread_saved_fp(tsk);

		frame.fp = thread_saved_fp(tsk);

		frame.sp = thread_saved_sp(tsk);

		frame.lr = 0;		/* recovered from the stack */

		frame.pc = thread_saved_pc(tsk);

#endif

	} else {

		register unsigned long current_sp asm ("sp");



		data.no_sched_functions = 0;

		asm("mov %0, fp" : "=r" (fp));

		frame.fp = (unsigned long)__builtin_frame_address(0);

		frame.sp = current_sp;

		frame.lr = (unsigned long)__builtin_return_address(0);

		frame.pc = (unsigned long)save_stack_trace_tsk;

	}



	walk_stackframe(fp, base, base + THREAD_SIZE, save_trace, &data);

	walk_stackframe(&frame, save_trace, &data);

	if (trace->nr_entries < trace->max_entries)

		trace->entries[trace->nr_entries++] = ULONG_MAX;

}

arch/arm/kernel/stacktrace.h

deleted100644 → 0
+0 −9
Original line number Diff line number Diff line 
struct stackframe {

	unsigned long fp;

	unsigned long sp;

	unsigned long lr;

	unsigned long pc;

};



int walk_stackframe(unsigned long fp, unsigned long low, unsigned long high,

		    int (*fn)(struct stackframe *, void *), void *data);