From: Benjamin Herrenschmidt Without this patch, executing an altivec instruction on an altivec capable CPU with a kernel that do not have CONFIG_ALTIVEC set would result in a kernel crash. (Fix forward ported from 2.4 by John Whitney ) --- 25-akpm/arch/ppc/kernel/head.S | 7 ++++--- 1 files changed, 4 insertions(+), 3 deletions(-) diff -puN arch/ppc/kernel/head.S~ppc32-altivec-exception-fix arch/ppc/kernel/head.S --- 25/arch/ppc/kernel/head.S~ppc32-altivec-exception-fix 2004-04-06 23:37:01.834691320 -0700 +++ 25-akpm/arch/ppc/kernel/head.S 2004-04-06 23:37:01.839690560 -0700 @@ -493,13 +493,14 @@ SystemCall: * We effectively remap it to 0x3000. */ . = 0xf00 - -#ifdef CONFIG_ALTIVEC b Trap_0f + . = 0xf20 +#ifdef CONFIG_ALTIVEC b AltiVecUnavailable -Trap_0f: #endif + +Trap_0f: EXCEPTION_PROLOG addi r3,r1,STACK_FRAME_OVERHEAD EXC_XFER_EE(0xf00, UnknownException) _