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Commit b93a531e authored by Jan Beulich's avatar Jan Beulich Committed by Ingo Molnar
Browse files

allow bug table entries to use relative pointers (and use it on x86-64) 



Impact: reduce bug table size

This allows reducing the bug table size by half. Perhaps there are
other 64-bit architectures that could also make use of this.

Signed-off-by: default avatarJan Beulich <jbeulich@novell.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 85072bd5

arch/x86/Kconfig

+4 −0
Original line number Diff line number Diff line
@@ -87,6 +87,10 @@ config GENERIC_IOMAP 
config GENERIC_BUG

	def_bool y

	depends on BUG

	select GENERIC_BUG_RELATIVE_POINTERS if X86_64



config GENERIC_BUG_RELATIVE_POINTERS

	bool



config GENERIC_HWEIGHT

	def_bool y

arch/x86/include/asm/bug.h

+1 −1
Original line number Diff line number Diff line
@@ -9,7 +9,7 @@ 
#ifdef CONFIG_X86_32

# define __BUG_C0	"2:\t.long 1b, %c0\n"

#else

# define __BUG_C0	"2:\t.quad 1b, %c0\n"

# define __BUG_C0	"2:\t.long 1b - 2b, %c0 - 2b\n"

#endif



#define BUG()							\

include/asm-generic/bug.h

+8 −0
Original line number Diff line number Diff line
@@ -8,9 +8,17 @@ 
#ifdef CONFIG_GENERIC_BUG

#ifndef __ASSEMBLY__

struct bug_entry {

#ifndef CONFIG_GENERIC_BUG_RELATIVE_POINTERS

	unsigned long	bug_addr;

#else

	signed int	bug_addr_disp;

#endif

#ifdef CONFIG_DEBUG_BUGVERBOSE

#ifndef CONFIG_GENERIC_BUG_RELATIVE_POINTERS

	const char	*file;

#else

	signed int	file_disp;

#endif

	unsigned short	line;

#endif

	unsigned short	flags;

lib/bug.c

+17 −2
Original line number Diff line number Diff line
@@ -5,6 +5,8 @@ 


  CONFIG_BUG - emit BUG traps.  Nothing happens without this.

  CONFIG_GENERIC_BUG - enable this code.

  CONFIG_GENERIC_BUG_RELATIVE_POINTERS - use 32-bit pointers relative to

	the containing struct bug_entry for bug_addr and file.

  CONFIG_DEBUG_BUGVERBOSE - emit full file+line information for each BUG



  CONFIG_BUG and CONFIG_DEBUG_BUGVERBOSE are potentially user-settable
@@ -43,6 +45,15 @@ 


extern const struct bug_entry __start___bug_table[], __stop___bug_table[];



static inline unsigned long bug_addr(const struct bug_entry *bug)

{

#ifndef CONFIG_GENERIC_BUG_RELATIVE_POINTERS

	return bug->bug_addr;

#else

	return (unsigned long)bug + bug->bug_addr_disp;

#endif

}



#ifdef CONFIG_MODULES

static LIST_HEAD(module_bug_list);
@@ -55,7 +66,7 @@ static const struct bug_entry *module_find_bug(unsigned long bugaddr) 
		unsigned i;



		for (i = 0; i < mod->num_bugs; ++i, ++bug)

			if (bugaddr == bug->bug_addr)

			if (bugaddr == bug_addr(bug))

				return bug;

	}

	return NULL;
@@ -108,7 +119,7 @@ const struct bug_entry *find_bug(unsigned long bugaddr) 
	const struct bug_entry *bug;



	for (bug = __start___bug_table; bug < __stop___bug_table; ++bug)

		if (bugaddr == bug->bug_addr)

		if (bugaddr == bug_addr(bug))

			return bug;



	return module_find_bug(bugaddr);
@@ -133,7 +144,11 @@ enum bug_trap_type report_bug(unsigned long bugaddr, struct pt_regs *regs) 


	if (bug) {

#ifdef CONFIG_DEBUG_BUGVERBOSE

#ifndef CONFIG_GENERIC_BUG_RELATIVE_POINTERS

		file = bug->file;

#else

		file = (const char *)bug + bug->file_disp;

#endif

		line = bug->line;

#endif

		warning = (bug->flags & BUGFLAG_WARNING) != 0;