Commit 2b14a78c authored by Andi Kleen's avatar Andi Kleen Committed by Andi Kleen
Browse files

[PATCH] i386: Do stacktracer conversion too 



Following x86-64 patches. Reuses code from them in fact.

Convert the standard backtracer to do all output using
callbacks.   Use the x86-64 stack tracer implementation
that uses these callbacks to implement the stacktrace interface.

This allows to use the new dwarf2 unwinder for stacktrace
and get better backtraces.

Cc: mingo@elte.hu

Signed-off-by: default avatarAndi Kleen <ak@suse.de>
parent be7a9170

arch/i386/kernel/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -81,4 +81,5 @@ $(obj)/vsyscall-syms.o: $(src)/vsyscall.lds \ 
	$(call if_changed,syscall)



k8-y                      += ../../x86_64/kernel/k8.o

stacktrace-y		  += ../../x86_64/kernel/stacktrace.o

arch/i386/kernel/stacktrace.c

deleted100644 → 0
+0 −93
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.

 */

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

{

	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, trace->skip, context, stack, ebp);

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

		if (!stack || trace->nr_entries >= trace->max_entries)

			break;

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

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

			break;

	}

}

arch/i386/kernel/traps.c

+80 −28
Original line number Diff line number Diff line
@@ -51,6 +51,7 @@ 
#include <asm/smp.h>

#include <asm/arch_hooks.h>

#include <asm/kdebug.h>

#include <asm/stacktrace.h>



#include <linux/module.h>
@@ -118,26 +119,16 @@ static inline int valid_stack_ptr(struct thread_info *tinfo, void *p) 
		p < (void *)tinfo + THREAD_SIZE - 3;

}



/*

 * Print one address/symbol entries per line.

 */

static inline void print_addr_and_symbol(unsigned long addr, char *log_lvl)

{

	printk(" [<%08lx>] ", addr);



	print_symbol("%s\n", addr);

}



static inline unsigned long print_context_stack(struct thread_info *tinfo,

				unsigned long *stack, unsigned long ebp,

				char *log_lvl)

				struct stacktrace_ops *ops, void *data)

{

	unsigned long addr;



#ifdef	CONFIG_FRAME_POINTER

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

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

		print_addr_and_symbol(addr, log_lvl);

		ops->address(data, addr);

		/*

		 * break out of recursive entries (such as

		 * end_of_stack_stop_unwind_function):
@@ -150,28 +141,35 @@ static inline unsigned long print_context_stack(struct thread_info *tinfo, 
	while (valid_stack_ptr(tinfo, stack)) {

		addr = *stack++;

		if (__kernel_text_address(addr))

			print_addr_and_symbol(addr, log_lvl);

			ops->address(data, addr);

	}

#endif

	return ebp;

}



struct ops_and_data {

	struct stacktrace_ops *ops;

	void *data;

};



static asmlinkage int

show_trace_unwind(struct unwind_frame_info *info, void *log_lvl)

dump_trace_unwind(struct unwind_frame_info *info, void *data)

{

	struct ops_and_data *oad = (struct ops_and_data *)data;

	int n = 0;



	while (unwind(info) == 0 && UNW_PC(info)) {

		n++;

		print_addr_and_symbol(UNW_PC(info), log_lvl);

		oad->ops->address(oad->data, UNW_PC(info));

		if (arch_unw_user_mode(info))

			break;

	}

	return n;

}



static void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,

			       unsigned long *stack, char *log_lvl)

void dump_trace(struct task_struct *task, struct pt_regs *regs,

	        unsigned long *stack,

		struct stacktrace_ops *ops, void *data)

{

	unsigned long ebp;
@@ -181,31 +179,37 @@ static void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs, 
	if (call_trace >= 0) {

		int unw_ret = 0;

		struct unwind_frame_info info;

		struct ops_and_data oad = { .ops = ops, .data = data };



		if (regs) {

			if (unwind_init_frame_info(&info, task, regs) == 0)

				unw_ret = show_trace_unwind(&info, log_lvl);

				unw_ret = dump_trace_unwind(&info, &oad);

		} else if (task == current)

			unw_ret = unwind_init_running(&info, show_trace_unwind, log_lvl);

			unw_ret = unwind_init_running(&info, dump_trace_unwind, &oad);

		else {

			if (unwind_init_blocked(&info, task) == 0)

				unw_ret = show_trace_unwind(&info, log_lvl);

				unw_ret = dump_trace_unwind(&info, &oad);

		}

		if (unw_ret > 0) {

			if (call_trace == 1 && !arch_unw_user_mode(&info)) {

				print_symbol("DWARF2 unwinder stuck at %s\n",

				ops->warning_symbol(data, "DWARF2 unwinder stuck at %s\n",

					     UNW_PC(&info));

				if (UNW_SP(&info) >= PAGE_OFFSET) {

					printk("Leftover inexact backtrace:\n");

					ops->warning(data, "Leftover inexact backtrace:\n");

					stack = (void *)UNW_SP(&info);

				} else

					printk("Full inexact backtrace again:\n");

					ops->warning(data, "Full inexact backtrace again:\n");

			} else if (call_trace >= 1)

				return;

			else

				printk("Full inexact backtrace again:\n");

				ops->warning(data, "Full inexact backtrace again:\n");

		} else

			printk("Inexact backtrace:\n");

			ops->warning(data, "Inexact backtrace:\n");

	} else 	if (!stack) {

		unsigned long dummy;

		stack = &dummy;

		if (task && task != current)

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

	}



	if (task == current) {
@@ -220,15 +224,63 @@ static void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs, 
		struct thread_info *context;

		context = (struct thread_info *)

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

		ebp = print_context_stack(context, stack, ebp, log_lvl);

		ebp = print_context_stack(context, stack, ebp, ops, data);

		/* Should be after the line below, but somewhere

		   in early boot context comes out corrupted and we

		   can't reference it -AK */

		if (ops->stack(data, "IRQ") < 0)

			break;

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

		if (!stack)

			break;

		printk("%s =======================\n", log_lvl);

	}

}

EXPORT_SYMBOL(dump_trace);



static void

print_trace_warning_symbol(void *data, char *msg, unsigned long symbol)

{

	printk(data);

	print_symbol(msg, symbol);

	printk("\n");

}



static void print_trace_warning(void *data, char *msg)

{

	printk("%s%s\n", (char *)data, msg);

}



static int print_trace_stack(void *data, char *name)

{

	return 0;

}



/*

 * Print one address/symbol entries per line.

 */

static void print_trace_address(void *data, unsigned long addr)

{

	printk("%s [<%08lx>] ", (char *)data, addr);

	print_symbol("%s\n", addr);

}



static struct stacktrace_ops print_trace_ops = {

	.warning = print_trace_warning,

	.warning_symbol = print_trace_warning_symbol,

	.stack = print_trace_stack,

	.address = print_trace_address,

};



static void

show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,

		   unsigned long * stack, char *log_lvl)

{

	dump_trace(task, regs, stack, &print_trace_ops, log_lvl);

	printk("%s =======================\n", log_lvl);

}



void show_trace(struct task_struct *task, struct pt_regs *regs, unsigned long * stack)

void show_trace(struct task_struct *task, struct pt_regs *regs,

		unsigned long * stack)

{

	show_trace_log_lvl(task, regs, stack, "");

}

include/asm-i386/stacktrace.h

0 → 100644
+1 −0
Original line number Diff line number Diff line 
#include <asm-x86_64/stacktrace.h>

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