[PATCH] powerpc: fix altivec_unavailable_exception Oopses

[Alan Curry]

Kumar Gala writes the following:
>
>Would you mine providing a patch for arch/ppc/kernel/head.S and  
>adding a signed-off-by line.

OK, combined patch... applies clean to 2.6.16-rc4, applies with fuzz to
2.6.15.4, both compiled and tested. Patch prevents Oopsing of
CONFIG_ALTIVEC=n kernel by user executing altivec instruction in both cases.

Signed-off-by: Alan Curry <pacman at TheWorld.com>

--- arch/ppc/kernel/head.S.orig	2006-02-21 20:58:08.000000000 -0500
+++ arch/ppc/kernel/head.S	2006-02-21 20:58:11.000000000 -0500
@@ -751,6 +751,7 @@ AltiVecUnavailable:
 #ifdef CONFIG_ALTIVEC
 	bne	load_up_altivec		/* if from user, just load it up */
 #endif /* CONFIG_ALTIVEC */
+	addi	r3,r1,STACK_FRAME_OVERHEAD
 	EXC_XFER_EE_LITE(0xf20, altivec_unavailable_exception)
 
 #ifdef CONFIG_PPC64BRIDGE
--- arch/powerpc/kernel/head_32.S.orig	2006-02-21 15:58:18.000000000 -0500
+++ arch/powerpc/kernel/head_32.S	2006-02-21 15:59:23.000000000 -0500
@@ -714,6 +714,7 @@ AltiVecUnavailable:
 #ifdef CONFIG_ALTIVEC
 	bne	load_up_altivec		/* if from user, just load it up */
 #endif /* CONFIG_ALTIVEC */
+	addi	r3,r1,STACK_FRAME_OVERHEAD
 	EXC_XFER_EE_LITE(0xf20, altivec_unavailable_exception)
 
 PerformanceMonitor: