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Commit 4a7c7197 authored by Ingo Molnar's avatar Ingo Molnar Committed by Linus Torvalds
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[PATCH] lockdep: stacktrace subsystem, i386 support 



Framework to generate and save stacktraces quickly, without printing anything
to the console.  i386 support.

Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarArjan van de Ven <arjan@linux.intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent cbbd1fa7

arch/i386/Kconfig

+4 −0
Original line number Diff line number Diff line
@@ -18,6 +18,10 @@ config GENERIC_TIME 
	bool

	default y



config STACKTRACE_SUPPORT

	bool

	default y



config SEMAPHORE_SLEEPERS

	bool

	default y

arch/i386/kernel/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -9,6 +9,7 @@ obj-y := process.o semaphore.o signal.o entry.o traps.o irq.o \ 
		pci-dma.o i386_ksyms.o i387.o bootflag.o \

		quirks.o i8237.o topology.o alternative.o i8253.o tsc.o



obj-$(CONFIG_STACKTRACE)	+= stacktrace.o

obj-y				+= cpu/

obj-y				+= acpi/

obj-$(CONFIG_X86_BIOS_REBOOT)	+= reboot.o

arch/i386/kernel/stacktrace.c

0 → 100644
+98 −0
Original line number Diff line number Diff line 
/*

 * arch/i386/kernel/stacktrace.c

 *

 * Stack trace management functions

 *

 *  Copyright (C) 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>

 */

#include <linux/sched.h>

#include <linux/stacktrace.h>



static inline int valid_stack_ptr(struct thread_info *tinfo, void *p)

{

	return	p > (void *)tinfo &&

		p < (void *)tinfo + THREAD_SIZE - 3;

}



/*

 * Save stack-backtrace addresses into a stack_trace buffer:

 */

static inline unsigned long

save_context_stack(struct stack_trace *trace, unsigned int skip,

		   struct thread_info *tinfo, unsigned long *stack,

		   unsigned long ebp)

{

	unsigned long addr;



#ifdef CONFIG_FRAME_POINTER

	while (valid_stack_ptr(tinfo, (void *)ebp)) {

		addr = *(unsigned long *)(ebp + 4);

		if (!skip)

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

		else

			skip--;

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

			break;

		/*

		 * break out of recursive entries (such as

		 * end_of_stack_stop_unwind_function):

	 	 */

		if (ebp == *(unsigned long *)ebp)

			break;



		ebp = *(unsigned long *)ebp;

	}

#else

	while (valid_stack_ptr(tinfo, stack)) {

		addr = *stack++;

		if (__kernel_text_address(addr)) {

			if (!skip)

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

			else

				skip--;

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

				break;

		}

	}

#endif



	return ebp;

}



/*

 * Save stack-backtrace addresses into a stack_trace buffer.

 * If all_contexts is set, all contexts (hardirq, softirq and process)

 * are saved. If not set then only the current context is saved.

 */

void save_stack_trace(struct stack_trace *trace,

		      struct task_struct *task, int all_contexts,

		      unsigned int skip)

{

	unsigned long ebp;

	unsigned long *stack = &ebp;



	WARN_ON(trace->nr_entries || !trace->max_entries);



	if (!task || task == current) {

		/* Grab ebp right from our regs: */

		asm ("movl %%ebp, %0" : "=r" (ebp));

	} else {

		/* ebp is the last reg pushed by switch_to(): */

		ebp = *(unsigned long *) task->thread.esp;

	}



	while (1) {

		struct thread_info *context = (struct thread_info *)

				((unsigned long)stack & (~(THREAD_SIZE - 1)));



		ebp = save_context_stack(trace, skip, context, stack, ebp);

		stack = (unsigned long *)context->previous_esp;

		if (!all_contexts || !stack ||

				trace->nr_entries >= trace->max_entries)

			break;

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

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

			break;

	}

}