[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>

4 files changed, 21 insertions, 31 deletions

diff --git a/arch/i386/Kconfig b/arch/i386/Kconfig
index ea70359..c2362c7 100644
--- a/arch/i386/Kconfig
+++ b/arch/i386/Kconfig
@@ -49,6 +49,11 @@ config GENERIC_IOMAP
 	bool
 	default y
 
+config GENERIC_BUG
+	bool
+	default y
+	depends on BUG
+
 config GENERIC_HWEIGHT
 	bool
 	default y
diff --git a/arch/i386/kernel/module.c b/arch/i386/kernel/module.c
index d7d9c8b..3db0a544 100644
--- a/arch/i386/kernel/module.c
+++ b/arch/i386/kernel/module.c
@@ -21,6 +21,7 @@
 #include <linux/fs.h>
 #include <linux/string.h>
 #include <linux/kernel.h>
+#include <linux/bug.h>
 
 #if 0
 #define DEBUGP printk
@@ -141,10 +142,11 @@ int module_finalize(const Elf_Ehdr *hdr,
 		apply_paravirt(pseg, pseg + para->sh_size);
 	}
 
-	return 0;
+	return module_bug_finalize(hdr, sechdrs, me);
 }
 
 void module_arch_cleanup(struct module *mod)
 {
 	alternatives_smp_module_del(mod);
+	module_bug_cleanup(mod);
 }
diff --git a/arch/i386/kernel/traps.c b/arch/i386/kernel/traps.c
index 68de48e..2b30dbf 100644
--- a/arch/i386/kernel/traps.c
+++ b/arch/i386/kernel/traps.c
@@ -30,6 +30,7 @@
 #include <linux/unwind.h>
 #include <linux/uaccess.h>
 #include <linux/nmi.h>
+#include <linux/bug.h>
 
 #ifdef CONFIG_EISA
 #include <linux/ioport.h>
@@ -420,43 +421,22 @@ void show_registers(struct pt_regs *regs)
 	printk("\n");
 }	
 
-static void handle_BUG(struct pt_regs *regs)
+int is_valid_bugaddr(unsigned long eip)
 {
-	unsigned long eip = regs->eip;
 	unsigned short ud2;
 
 	if (eip < PAGE_OFFSET)
-		return;
+		return 0;
 	if (probe_kernel_address((unsigned short *)eip, ud2))
-		return;
-	if (ud2 != 0x0b0f)
-		return;
-
-	printk(KERN_EMERG "------------[ cut here ]------------\n");
-
-#ifdef CONFIG_DEBUG_BUGVERBOSE
-	do {
-		unsigned short line;
-		char *file;
-		char c;
-
-		if (probe_kernel_address((unsigned short *)(eip + 2), line))
-			break;
-		if (probe_kernel_address((char **)(eip + 4), file) ||
-		    (unsigned long)file < PAGE_OFFSET ||
-			probe_kernel_address(file, c))
-			file = "<bad filename>";
+		return 0;
 
-		printk(KERN_EMERG "kernel BUG at %s:%d!\n", file, line);
-		return;
-	} while (0);
-#endif
-	printk(KERN_EMERG "Kernel BUG at [verbose debug info unavailable]\n");
+	return ud2 == 0x0b0f;
 }
 
-/* This is gone through when something in the kernel
- * has done something bad and is about to be terminated.
-*/
+/*
+ * This is gone through when something in the kernel has done something bad and
+ * is about to be terminated.
+ */
 void die(const char * str, struct pt_regs * regs, long err)
 {
 	static struct {
@@ -488,7 +468,8 @@ void die(const char * str, struct pt_regs * regs, long err)
 		unsigned long esp;
 		unsigned short ss;
 
-		handle_BUG(regs);
+		report_bug(regs->eip);
+
 		printk(KERN_EMERG "%s: %04lx [#%d]\n", str, err & 0xffff, ++die_counter);
 #ifdef CONFIG_PREEMPT
 		printk(KERN_EMERG "PREEMPT ");
diff --git a/arch/i386/kernel/vmlinux.lds.S b/arch/i386/kernel/vmlinux.lds.S
index 56e6ad5c..16d3c71 100644
--- a/arch/i386/kernel/vmlinux.lds.S
+++ b/arch/i386/kernel/vmlinux.lds.S
@@ -57,6 +57,8 @@ SECTIONS
 
   RODATA
 
+  BUG_TABLE
+
   . = ALIGN(4);
   .tracedata : AT(ADDR(.tracedata) - LOAD_OFFSET) {
   	__tracedata_start = .;