[PATCH] Generic BUG for x86-64
This makes x86-64 use the generic BUG machinery.
The main advantage in using the generic BUG machinery for x86-64 is that
the inlined overhead of BUG is just the ud2a instruction; the file+line
information are no longer inlined into the instruction stream. This
reduces cache pollution.
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>
diff --git a/arch/x86_64/kernel/traps.c b/arch/x86_64/kernel/traps.c
index a1641ff..b54ccc0 100644
--- a/arch/x86_64/kernel/traps.c
+++ b/arch/x86_64/kernel/traps.c
@@ -31,6 +31,7 @@
#include <linux/kexec.h>
#include <linux/unwind.h>
#include <linux/uaccess.h>
+#include <linux/bug.h>
#include <asm/system.h>
#include <asm/io.h>
@@ -524,30 +525,15 @@
printk("\n");
}
-void handle_BUG(struct pt_regs *regs)
-{
- struct bug_frame f;
- long len;
- const char *prefix = "";
+int is_valid_bugaddr(unsigned long rip)
+{
+ unsigned short ud2;
- if (user_mode(regs))
- return;
- if (__copy_from_user(&f, (const void __user *) regs->rip,
- sizeof(struct bug_frame)))
- return;
- if (f.filename >= 0 ||
- f.ud2[0] != 0x0f || f.ud2[1] != 0x0b)
- return;
- len = __strnlen_user((char *)(long)f.filename, PATH_MAX) - 1;
- if (len < 0 || len >= PATH_MAX)
- f.filename = (int)(long)"unmapped filename";
- else if (len > 50) {
- f.filename += len - 50;
- prefix = "...";
- }
- printk("----------- [cut here ] --------- [please bite here ] ---------\n");
- printk(KERN_ALERT "Kernel BUG at %s%.50s:%d\n", prefix, (char *)(long)f.filename, f.line);
-}
+ if (__copy_from_user(&ud2, (const void __user *) rip, sizeof(ud2)))
+ return 0;
+
+ return ud2 == 0x0b0f;
+}
#ifdef CONFIG_BUG
void out_of_line_bug(void)
@@ -627,7 +613,9 @@
{
unsigned long flags = oops_begin();
- handle_BUG(regs);
+ if (!user_mode(regs))
+ report_bug(regs->rip);
+
__die(str, regs, err);
oops_end(flags);
do_exit(SIGSEGV);