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 <jbeulich@novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index ac22bb7..ab98cca 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -87,6 +87,10 @@
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 3def206..d9cf1cd 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 12c07c1..4c794d7 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 bfeafd6..300e41a 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 @@
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 *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 @@
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;