[PATCH] ppc32: oops on kernel altivec assist exceptions
authorPaul Mackerras <paulus@samba.org>
Sat, 16 Apr 2005 22:24:17 +0000 (15:24 -0700)
committerLinus Torvalds <torvalds@ppc970.osdl.org>
Sat, 16 Apr 2005 22:24:17 +0000 (15:24 -0700)
If we should happen to get an altivec assist exception while executing in
the kernel, we will currently try to handle it and fail, and end up oopsing
with (apparently) a segfault.  (An altivec assist exception occurs for
floating-point altivec instructions with denormalized inputs or outputs if
the altivec unit is in java mode.)

This patch checks explicitly if we are in user mode and prints a useful
message if not.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
arch/ppc/kernel/traps.c

index ed5c7acdca70a76780dfb4a378642fed9fe88f48..aec225b402ae5f0558619908596bba3c2cf3943a 100644 (file)
@@ -805,6 +805,13 @@ void AltivecAssistException(struct pt_regs *regs)
        if (regs->msr & MSR_VEC)
                giveup_altivec(current);
        preempt_enable();
+       if (!user_mode(regs)) {
+               printk(KERN_ERR "altivec assist exception in kernel mode"
+                      " at %lx\n", regs->nip);
+               debugger(regs);
+               die("altivec assist exception", regs, SIGFPE);
+               return;
+       }
 
        err = emulate_altivec(regs);
        if (err == 0) {