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Commit f16fb1ec authored by Russell King's avatar Russell King Committed by Russell King
Browse files

[ARM] Add stacktrace support and make oprofile use it 



Add support for stacktrace.  Use the new stacktrace code with
oprofile instead of it's version; there's no point having
multiple versions of stacktracing in the kernel.

Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent ed519ded

arch/arm/Kconfig

+8 −0
Original line number Diff line number Diff line
@@ -67,6 +67,14 @@ config GENERIC_HARDIRQS 
	bool

	default y



config STACKTRACE_SUPPORT

	bool

	default y



config LOCKDEP_SUPPORT

	bool

	default y



config TRACE_IRQFLAGS_SUPPORT

	bool

	default y

arch/arm/kernel/Makefile

+2 −2
Original line number Diff line number Diff line
@@ -7,8 +7,8 @@ AFLAGS_head.o := -DTEXT_OFFSET=$(TEXT_OFFSET) 
# Object file lists.



obj-y		:= compat.o entry-armv.o entry-common.o irq.o \

		   process.o ptrace.o semaphore.o setup.o signal.o sys_arm.o \

		   time.o traps.o

		   process.o ptrace.o semaphore.o setup.o signal.o \

		   sys_arm.o stacktrace.o time.o traps.o



obj-$(CONFIG_ISA_DMA_API)	+= dma.o

obj-$(CONFIG_ARCH_ACORN)	+= ecard.o

arch/arm/kernel/stacktrace.c

0 → 100644
+73 −0
Original line number Diff line number Diff line 
#include <linux/sched.h>

#include <linux/stacktrace.h>



#include "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 {

		/*

		 * Check current frame pointer is within bounds

		 */

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

			break;



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



		if (fn(frame, data))

			break;



		/*

		 * 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);



	return 0;

}



#ifdef CONFIG_STACKTRACE

struct stack_trace_data {

	struct stack_trace *trace;

	unsigned int skip;

};



static int save_trace(struct stackframe *frame, void *d)

{

	struct stack_trace_data *data = d;

	struct stack_trace *trace = data->trace;



	if (data->skip) {

		data->skip--;

		return 0;

	}



	trace->entries[trace->nr_entries++] = frame->lr;



	return trace->nr_entries >= trace->max_entries;

}



void save_stack_trace(struct stack_trace *trace, struct task_struct *task)

{

	struct stack_trace_data data;

	unsigned long fp, base;



	data.trace = trace;

	data.skip = trace->skip;



	if (task) {

		base = (unsigned long)task_stack_page(task);

		fp = 0; /* FIXME */

	} else {

		base = (unsigned long)task_stack_page(current);

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

	}



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

}

#endif

arch/arm/kernel/stacktrace.h

0 → 100644
+9 −0
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);

arch/arm/oprofile/backtrace.c

+17 −52
Original line number Diff line number Diff line
@@ -19,6 +19,19 @@ 
#include <asm/ptrace.h>

#include <asm/uaccess.h>



#include "../kernel/stacktrace.h"



static int report_trace(struct stackframe *frame, void *d)

{

	unsigned int *depth = d;



	if (*depth) {

		oprofile_add_trace(frame->lr);

		(*depth)--;

	}



	return *depth == 0;

}



/*

 * The registers we're interested in are at the end of the variable
@@ -32,21 +45,6 @@ struct frame_tail { 
	unsigned long lr;

} __attribute__((packed));





#ifdef CONFIG_FRAME_POINTER

static struct frame_tail* kernel_backtrace(struct frame_tail *tail)

{

	oprofile_add_trace(tail->lr);



	/* frame pointers should strictly progress back up the stack

	 * (towards higher addresses) */

	if (tail >= tail->fp)

		return NULL;



	return tail->fp-1;

}

#endif



static struct frame_tail* user_backtrace(struct frame_tail *tail)

{

	struct frame_tail buftail[2];
@@ -67,47 +65,14 @@ static struct frame_tail* user_backtrace(struct frame_tail *tail) 
	return buftail[0].fp-1;

}



/*

 * |             | /\ Higher addresses

 * |             |

 * --------------- stack base (address of current_thread_info)

 * | thread info |

 * .             .

 * |    stack    |

 * --------------- saved regs->ARM_fp value if valid (frame_tail address)

 * .             .

 * --------------- struct pt_regs stored on stack (struct pt_regs *)

 * |             |

 * .             .

 * |             |

 * --------------- %esp

 * |             |

 * |             | \/ Lower addresses

 *

 * Thus, &pt_regs <-> stack base restricts the valid(ish) fp values

 */

static int valid_kernel_stack(struct frame_tail *tail, struct pt_regs *regs)

{

	unsigned long tailaddr = (unsigned long)tail;

	unsigned long stack = (unsigned long)regs;

	unsigned long stack_base = (stack & ~(THREAD_SIZE - 1)) + THREAD_SIZE;



	return (tailaddr > stack) && (tailaddr < stack_base);

}



void arm_backtrace(struct pt_regs * const regs, unsigned int depth)

{

	struct frame_tail *tail;



	tail = ((struct frame_tail *) regs->ARM_fp) - 1;

	struct frame_tail *tail = ((struct frame_tail *) regs->ARM_fp) - 1;



	if (!user_mode(regs)) {



#ifdef CONFIG_FRAME_POINTER

		while (depth-- && tail && valid_kernel_stack(tail, regs)) {

			tail = kernel_backtrace(tail);

		}

#endif

		unsigned long base = ((unsigned long)regs) & ~(THREAD_SIZE - 1);

		walk_stackframe(regs->ARM_fp, base, base + THREAD_SIZE,

				report_trace, &depth);

		return;

	}