From b93a531e315e97ef00367099e6b5f19651936e20 Mon Sep 17 00:00:00 2001 From: Jan Beulich Date: Tue, 16 Dec 2008 11:40:27 +0000 Subject: [PATCH] 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: Jan Beulich Signed-off-by: Ingo Molnar --- arch/x86/Kconfig | 4 ++++ arch/x86/include/asm/bug.h | 2 +- include/asm-generic/bug.h | 8 ++++++++ lib/bug.c | 19 +++++++++++++++++-- 4 files changed, 30 insertions(+), 3 deletions(-) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index ac22bb7719f..ab98cca84e1 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -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 diff --git a/arch/x86/include/asm/bug.h b/arch/x86/include/asm/bug.h index 3def2065fce..d9cf1cd156d 100644 --- a/arch/x86/include/asm/bug.h +++ b/arch/x86/include/asm/bug.h @@ -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() \ diff --git a/include/asm-generic/bug.h b/include/asm-generic/bug.h index 12c07c1866b..4c794d73fb8 100644 --- a/include/asm-generic/bug.h +++ b/include/asm-generic/bug.h @@ -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; diff --git a/lib/bug.c b/lib/bug.c index bfeafd60ee9..300e41afbf9 100644 --- a/lib/bug.c +++ b/lib/bug.c @@ -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; -- 2.39.5