[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: Jeremy 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: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 20 insertions, 8 deletions

diff --git a/include/asm-i386/bug.h b/include/asm-i386/bug.h
index 8062cdbf2587..b0fd78ca2619 100644
--- a/include/asm-i386/bug.h
+++ b/include/asm-i386/bug.h
@@ -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__))
+#define BUG()                                                           \
+        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