parisc: fix kernel crash (protection id trap) when compiling ruby1.9

On Wed, Dec 17, 2008 at 11:46:05PM +0100, Helge Deller wrote:
>

Honestly, I can't decide whether to apply this. It really should never
happen in the kernel, since the kernel can guarantee it won't get the
access rights failure (highest privilege level, and can set %sr and
%protid to whatever it wants.)

It really genuinely is a bug that probably should panic the kernel. The
only precedent I can easily see is x86 fixing up a bad iret with a
general protection fault, which is more or less analogous to code 27
here.

On the other hand, taking the exception on a userspace access really
isn't all that critical, and there's fundamentally little reason for the
kernel not to SIGSEGV the process, and continue...

Argh.

(btw, I've instrumented my do_sys_poll with a pile of assertions that
 %cr8 << 1 == %sr3 == current->mm.context... let's see if where we're
 getting corrupted is deterministic, though, I would guess that it won't
 be.)

Signed-off-by: Kyle McMartin <kyle@mcmartin.ca>

1 files changed, 2 insertions, 0 deletions

diff --git a/arch/parisc/include/asm/uaccess.h b/arch/parisc/include/asm/uaccess.h
index 4878b9501f24..1c6dbb6f6e56 100644
--- a/arch/parisc/include/asm/uaccess.h
+++ b/arch/parisc/include/asm/uaccess.h
@@ -241,4 +241,6 @@ unsigned long copy_in_user(void __user *dst, const void __user *src, unsigned lo
 #define __copy_to_user_inatomic __copy_to_user
 #define __copy_from_user_inatomic __copy_from_user
 
+int fixup_exception(struct pt_regs *regs);
+
 #endif /* __PARISC_UACCESS_H */