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>

2 files changed, 5 insertions, 1 deletions

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index ac22bb7719f7..ab98cca84e1b 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 3def2065fcea..d9cf1cd156d2 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()                                                   \