Commit 4552d5dc authored by Jan Beulich's avatar Jan Beulich Committed by Linus Torvalds
Browse files

[PATCH] x86_64: reliable stack trace support 



These are the generic bits needed to enable reliable stack traces based
on Dwarf2-like (.eh_frame) unwind information. Subsequent patches will
enable x86-64 and i386 to make use of this.

Thanks to Andi Kleen and Ingo Molnar, who pointed out several possibilities
for improvement.

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 2b28592b

include/linux/kernel.h

+7 −0
Original line number Diff line number Diff line
@@ -32,6 +32,7 @@ extern const char linux_banner[]; 


#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))

#define ALIGN(x,a) (((x)+(a)-1)&~((a)-1))

#define FIELD_SIZEOF(t, f) (sizeof(((t*)0)->f))



#define	KERN_EMERG	"<0>"	/* system is unusable			*/

#define	KERN_ALERT	"<1>"	/* action must be taken immediately	*/
@@ -336,6 +337,12 @@ struct sysinfo { 
/* Force a compilation error if condition is true */

#define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)]))



/* Force a compilation error if condition is true, but also produce a

   result (of value 0 and type size_t), so the expression can be used

   e.g. in a structure initializer (or where-ever else comma expressions

   aren't permitted). */

#define BUILD_BUG_ON_ZERO(e) (sizeof(char[1 - 2 * !!(e)]) - 1)



/* Trap pasters of __FUNCTION__ at compile-time */

#define __FUNCTION__ (__func__)

include/linux/module.h

+3 −0
Original line number Diff line number Diff line
@@ -285,6 +285,9 @@ struct module 
	/* The size of the executable code in each section.  */

	unsigned long init_text_size, core_text_size;



	/* The handle returned from unwind_add_table. */

	void *unwind_info;



	/* Arch-specific module values */

	struct mod_arch_specific arch;

include/linux/unwind.h

0 → 100644
+119 −0
Original line number Diff line number Diff line 
#ifndef _LINUX_UNWIND_H

#define _LINUX_UNWIND_H



/*

 * Copyright (C) 2002-2006 Novell, Inc.

 *	Jan Beulich <jbeulich@novell.com>

 * This code is released under version 2 of the GNU GPL.

 *

 * A simple API for unwinding kernel stacks.  This is used for

 * debugging and error reporting purposes.  The kernel doesn't need

 * full-blown stack unwinding with all the bells and whistles, so there

 * is not much point in implementing the full Dwarf2 unwind API.

 */



#include <linux/config.h>



struct module;



#ifdef CONFIG_STACK_UNWIND



#include <asm/unwind.h>



#ifndef ARCH_UNWIND_SECTION_NAME

#define ARCH_UNWIND_SECTION_NAME ".eh_frame"

#endif



/*

 * Initialize unwind support.

 */

extern void unwind_init(void);



extern void *unwind_add_table(struct module *,

                              const void *table_start,

                              unsigned long table_size);



extern void unwind_remove_table(void *handle, int init_only);



extern int unwind_init_frame_info(struct unwind_frame_info *,

                                  struct task_struct *,

                                  /*const*/ struct pt_regs *);



/*

 * Prepare to unwind a blocked task.

 */

extern int unwind_init_blocked(struct unwind_frame_info *,

                               struct task_struct *);



/*

 * Prepare to unwind the currently running thread.

 */

extern int unwind_init_running(struct unwind_frame_info *,

                               asmlinkage void (*callback)(struct unwind_frame_info *,

                                                           void *arg),

                               void *arg);



/*

 * Unwind to previous to frame.  Returns 0 if successful, negative

 * number in case of an error.

 */

extern int unwind(struct unwind_frame_info *);



/*

 * Unwind until the return pointer is in user-land (or until an error

 * occurs).  Returns 0 if successful, negative number in case of

 * error.

 */

extern int unwind_to_user(struct unwind_frame_info *);



#else



struct unwind_frame_info {};



static inline void unwind_init(void) {}



static inline void *unwind_add_table(struct module *mod,

                                     const void *table_start,

                                     unsigned long table_size)

{

	return NULL;

}



static inline void unwind_remove_table(void *handle, int init_only)

{

}



static inline int unwind_init_frame_info(struct unwind_frame_info *info,

                                         struct task_struct *tsk,

                                         const struct pt_regs *regs)

{

	return -ENOSYS;

}



static inline int unwind_init_blocked(struct unwind_frame_info *info,

                                      struct task_struct *tsk)

{

	return -ENOSYS;

}



static inline int unwind_init_running(struct unwind_frame_info *info,

                                      asmlinkage void (*cb)(struct unwind_frame_info *,

                                                            void *arg),

                                      void *arg)

{

	return -ENOSYS;

}



static inline int unwind(struct unwind_frame_info *info)

{

	return -ENOSYS;

}



static inline int unwind_to_user(struct unwind_frame_info *info)

{

	return -ENOSYS;

}



#endif



#endif /* _LINUX_UNWIND_H */

init/main.c

+2 −0
Original line number Diff line number Diff line
@@ -47,6 +47,7 @@ 
#include <linux/rmap.h>

#include <linux/mempolicy.h>

#include <linux/key.h>

#include <linux/unwind.h>



#include <asm/io.h>

#include <asm/bugs.h>
@@ -482,6 +483,7 @@ asmlinkage void __init start_kernel(void) 
		   __stop___param - __start___param,

		   &unknown_bootoption);

	sort_main_extable();

	unwind_init();

	trap_init();

	rcu_init();

	init_IRQ();

kernel/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock.o 
obj-$(CONFIG_UID16) += uid16.o

obj-$(CONFIG_MODULES) += module.o

obj-$(CONFIG_KALLSYMS) += kallsyms.o

obj-$(CONFIG_STACK_UNWIND) += unwind.o

obj-$(CONFIG_PM) += power/

obj-$(CONFIG_BSD_PROCESS_ACCT) += acct.o

obj-$(CONFIG_KEXEC) += kexec.o

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