Commit 91768d6c authored by Jeremy Fitzhardinge's avatar Jeremy Fitzhardinge Committed by Linus Torvalds
Browse files

[PATCH] Generic BUG for i386 



This makes i386 use the generic BUG machinery.  There are no functional
changes from the old i386 implementation.

The main advantage in using the generic BUG machinery for i386 is that the
inlined overhead of BUG is just the ud2a instruction; the file+line(+function)
information are no longer inlined into the instruction stream.  This reduces
cache pollution, and makes disassembly work properly.

Signed-off-by: default avatarJeremy Fitzhardinge <jeremy@goop.org>
Cc: Andi Kleen <ak@muc.de>
Cc: Hugh Dickens <hugh@veritas.com>
Cc: Michael Ellerman <michael@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 7664c5a1

arch/i386/Kconfig

+5 −0
Original line number Diff line number Diff line
@@ -49,6 +49,11 @@ config GENERIC_IOMAP 
	bool

	default y



config GENERIC_BUG

	bool

	default y

	depends on BUG



config GENERIC_HWEIGHT

	bool

	default y

arch/i386/kernel/module.c

+3 −1
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ 
#include <linux/fs.h>

#include <linux/string.h>

#include <linux/kernel.h>

#include <linux/bug.h>



#if 0

#define DEBUGP printk
@@ -141,10 +142,11 @@ int module_finalize(const Elf_Ehdr *hdr, 
		apply_paravirt(pseg, pseg + para->sh_size);

	}



	return 0;

	return module_bug_finalize(hdr, sechdrs, me);

}



void module_arch_cleanup(struct module *mod)

{

	alternatives_smp_module_del(mod);

	module_bug_cleanup(mod);

}

arch/i386/kernel/traps.c

+11 −30
Original line number Diff line number Diff line
@@ -30,6 +30,7 @@ 
#include <linux/unwind.h>

#include <linux/uaccess.h>

#include <linux/nmi.h>

#include <linux/bug.h>



#ifdef CONFIG_EISA

#include <linux/ioport.h>
@@ -420,42 +421,21 @@ void show_registers(struct pt_regs *regs) 
	printk("\n");

}	



static void handle_BUG(struct pt_regs *regs)

int is_valid_bugaddr(unsigned long eip)

{

	unsigned long eip = regs->eip;

	unsigned short ud2;



	if (eip < PAGE_OFFSET)

		return;

		return 0;

	if (probe_kernel_address((unsigned short *)eip, ud2))

		return;

	if (ud2 != 0x0b0f)

		return;



	printk(KERN_EMERG "------------[ cut here ]------------\n");



#ifdef CONFIG_DEBUG_BUGVERBOSE

	do {

		unsigned short line;

		char *file;

		char c;



		if (probe_kernel_address((unsigned short *)(eip + 2), line))

			break;

		if (probe_kernel_address((char **)(eip + 4), file) ||

		    (unsigned long)file < PAGE_OFFSET ||

			probe_kernel_address(file, c))

			file = "<bad filename>";

		return 0;



		printk(KERN_EMERG "kernel BUG at %s:%d!\n", file, line);

		return;

	} while (0);

#endif

	printk(KERN_EMERG "Kernel BUG at [verbose debug info unavailable]\n");

	return ud2 == 0x0b0f;

}



/* This is gone through when something in the kernel

 * has done something bad and is about to be terminated.

/*

 * This is gone through when something in the kernel has done something bad and

 * is about to be terminated.

 */

void die(const char * str, struct pt_regs * regs, long err)

{
@@ -488,7 +468,8 @@ void die(const char * str, struct pt_regs * regs, long err) 
		unsigned long esp;

		unsigned short ss;



		handle_BUG(regs);

		report_bug(regs->eip);



		printk(KERN_EMERG "%s: %04lx [#%d]\n", str, err & 0xffff, ++die_counter);

#ifdef CONFIG_PREEMPT

		printk(KERN_EMERG "PREEMPT ");

arch/i386/kernel/vmlinux.lds.S

+2 −0
Original line number Diff line number Diff line
@@ -57,6 +57,8 @@ SECTIONS 


  RODATA



  BUG_TABLE



  . = ALIGN(4);

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

  	__tracedata_start = .;

include/asm-i386/bug.h

+20 −8
Original line number Diff line number Diff line
@@ -4,20 +4,32 @@ 


/*

 * Tell the user there is some problem.

 * The offending file and line are encoded after the "officially

 * undefined" opcode for parsing in the trap handler.

 * The offending file and line are encoded encoded in the __bug_table section.

 */



#ifdef CONFIG_BUG

#define HAVE_ARCH_BUG



#ifdef CONFIG_DEBUG_BUGVERBOSE

#define BUG()								\

 __asm__ __volatile__(	"ud2\n"		\

			"\t.word %c0\n"	\

			"\t.long %c1\n"	\

			 : : "i" (__LINE__), "i" (__FILE__))

	do {								\

		asm volatile("1:\tud2\n"				\

			     ".pushsection __bug_table,\"a\"\n"		\

			     "2:\t.long 1b, %c0\n"			\

			     "\t.word %c1, 0\n"				\

			     "\t.org 2b+%c2\n"				\

			     ".popsection"				\

			     : : "i" (__FILE__), "i" (__LINE__),	\

			     "i" (sizeof(struct bug_entry)));		\

		for(;;) ;						\

	} while(0)



#else

#define BUG() __asm__ __volatile__("ud2\n")

#define BUG()								\

	do {								\

		asm volatile("ud2");					\

		for(;;) ;						\

	} while(0)

#endif

#endif

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