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Commit 176a2718 authored by Jan Beulich's avatar Jan Beulich Committed by Linus Torvalds
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[PATCH] i386: reliable stack trace support (i386) 



These are the i386-specific pieces to enable reliable stack traces. This is
going to be even more useful once CFI annotations get added to he assembly
code, namely to entry.S.

Signed-off-by: default avatarJan Beulich <jbeulich@novell.com>
Signed-off-by: default avatarAndi Kleen <ak@suse.de>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent dffead4e

arch/i386/kernel/entry.S

+29 −0
Original line number Diff line number Diff line
@@ -663,6 +663,35 @@ ENTRY(spurious_interrupt_bug) 
	pushl $do_spurious_interrupt_bug

	jmp error_code



#ifdef CONFIG_STACK_UNWIND

ENTRY(arch_unwind_init_running)

	movl	4(%esp), %edx

	movl	(%esp), %ecx

	leal	4(%esp), %eax

	movl	%ebx, EBX(%edx)

	xorl	%ebx, %ebx

	movl	%ebx, ECX(%edx)

	movl	%ebx, EDX(%edx)

	movl	%esi, ESI(%edx)

	movl	%edi, EDI(%edx)

	movl	%ebp, EBP(%edx)

	movl	%ebx, EAX(%edx)

	movl	$__USER_DS, DS(%edx)

	movl	$__USER_DS, ES(%edx)

	movl	%ebx, ORIG_EAX(%edx)

	movl	%ecx, EIP(%edx)

	movl	12(%esp), %ecx

	movl	$__KERNEL_CS, CS(%edx)

	movl	%ebx, EFLAGS(%edx)

	movl	%eax, OLDESP(%edx)

	movl	8(%esp), %eax

	movl	%ecx, 8(%esp)

	movl	EBX(%edx), %ebx

	movl	$__KERNEL_DS, OLDSS(%edx)

	jmpl	*%eax

ENDPROC(arch_unwind_init_running)

#endif



.section .rodata,"a"

#include "syscall_table.S"

arch/i386/kernel/process.c

+1 −1
Original line number Diff line number Diff line
@@ -312,7 +312,7 @@ void show_regs(struct pt_regs * regs) 
	cr3 = read_cr3();

	cr4 = read_cr4_safe();

	printk("CR0: %08lx CR2: %08lx CR3: %08lx CR4: %08lx\n", cr0, cr2, cr3, cr4);

	show_trace(NULL, &regs->esp);

	show_trace(NULL, regs, &regs->esp);

}



/*

arch/i386/kernel/traps.c

+40 −10
Original line number Diff line number Diff line
@@ -28,6 +28,7 @@ 
#include <linux/utsname.h>

#include <linux/kprobes.h>

#include <linux/kexec.h>

#include <linux/unwind.h>



#ifdef CONFIG_EISA

#include <linux/ioport.h>
@@ -47,7 +48,7 @@ 
#include <asm/desc.h>

#include <asm/i387.h>

#include <asm/nmi.h>



#include <asm/unwind.h>

#include <asm/smp.h>

#include <asm/arch_hooks.h>

#include <asm/kdebug.h>
@@ -170,14 +171,43 @@ static inline unsigned long print_context_stack(struct thread_info *tinfo, 
	return ebp;

}



static void show_trace_log_lvl(struct task_struct *task,

static asmlinkage void show_trace_unwind(struct unwind_frame_info *info, void *log_lvl)

{

	int printed = 0; /* nr of entries already printed on current line */



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

		printed = print_addr_and_symbol(UNW_PC(info), log_lvl, printed);

		if (arch_unw_user_mode(info))

			break;

	}

	if (printed)

		printk("\n");

}



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

			       unsigned long *stack, char *log_lvl)

{

	unsigned long ebp;

	struct unwind_frame_info info;



	if (!task)

		task = current;



	if (regs) {

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

			show_trace_unwind(&info, log_lvl);

			return;

		}

	} else if (task == current) {

		if (unwind_init_running(&info, show_trace_unwind, log_lvl) == 0)

			return;

	} else {

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

			show_trace_unwind(&info, log_lvl);

			return;

		}

	}



	if (task == current) {

		/* Grab ebp right from our regs */

		asm ("movl %%ebp, %0" : "=r" (ebp) : );
@@ -198,13 +228,13 @@ static void show_trace_log_lvl(struct task_struct *task, 
	}

}



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

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

{

	show_trace_log_lvl(task, stack, "");

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

}



static void show_stack_log_lvl(struct task_struct *task, unsigned long *esp,

			       char *log_lvl)

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

			       unsigned long *esp, char *log_lvl)

{

	unsigned long *stack;

	int i;
@@ -225,13 +255,13 @@ static void show_stack_log_lvl(struct task_struct *task, unsigned long *esp, 
		printk("%08lx ", *stack++);

	}

	printk("\n%sCall Trace:\n", log_lvl);

	show_trace_log_lvl(task, esp, log_lvl);

	show_trace_log_lvl(task, regs, esp, log_lvl);

}



void show_stack(struct task_struct *task, unsigned long *esp)

{

	printk("       ");

	show_stack_log_lvl(task, esp, "");

	show_stack_log_lvl(task, NULL, esp, "");

}



/*
@@ -241,7 +271,7 @@ void dump_stack(void) 
{

	unsigned long stack;



	show_trace(current, &stack);

	show_trace(current, NULL, &stack);

}



EXPORT_SYMBOL(dump_stack);
@@ -285,7 +315,7 @@ void show_registers(struct pt_regs *regs) 
		u8 __user *eip;



		printk("\n" KERN_EMERG "Stack: ");

		show_stack_log_lvl(NULL, (unsigned long *)esp, KERN_EMERG);

		show_stack_log_lvl(NULL, regs, (unsigned long *)esp, KERN_EMERG);



		printk(KERN_EMERG "Code: ");

arch/i386/kernel/vmlinux.lds.S

+9 −0
Original line number Diff line number Diff line
@@ -71,6 +71,15 @@ SECTIONS 
  .data.read_mostly : AT(ADDR(.data.read_mostly) - LOAD_OFFSET) { *(.data.read_mostly) }

  _edata = .;			/* End of data section */



#ifdef CONFIG_STACK_UNWIND

  . = ALIGN(4);

  .eh_frame : AT(ADDR(.eh_frame) - LOAD_OFFSET) {

	__start_unwind = .;

  	*(.eh_frame)

	__end_unwind = .;

  }

#endif



  . = ALIGN(THREAD_SIZE);	/* init_task */

  .data.init_task : AT(ADDR(.data.init_task) - LOAD_OFFSET) {

	*(.data.init_task)

include/asm-i386/processor.h

+1 −1
Original line number Diff line number Diff line
@@ -555,7 +555,7 @@ extern void prepare_to_copy(struct task_struct *tsk); 
extern int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags);



extern unsigned long thread_saved_pc(struct task_struct *tsk);

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

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



unsigned long get_wchan(struct task_struct *p);