From e522e2ea300e2345d287478fe034d995fecf96e2 Mon Sep 17 00:00:00 2001 From: Nicholas Piggin Date: Fri, 23 Mar 2018 15:53:38 +1000 Subject: powerpc/64s: Fix i-side SLB miss bad address handler saving nonvolatile GPRs commit 52396500f97c53860164debc7d4f759077853423 upstream. The SLB bad address handler's trap number fixup does not preserve the low bit that indicates nonvolatile GPRs have not been saved. This leads save_nvgprs to skip saving them, and subsequent functions and return from interrupt will think they are saved. This causes kernel branch-to-garbage debugging to not have correct registers, can also cause userspace to have its registers clobbered after a segfault. Fixes: f0f558b131db ("powerpc/mm: Preserve CFAR value on SLB miss caused by access to bogus address") Cc: stable@vger.kernel.org # v4.9+ Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman --- arch/powerpc/kernel/exceptions-64s.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch') diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S index 7614d1dd2c0b..94b5dfb087e9 100644 --- a/arch/powerpc/kernel/exceptions-64s.S +++ b/arch/powerpc/kernel/exceptions-64s.S @@ -723,7 +723,7 @@ EXC_COMMON_BEGIN(bad_addr_slb) ld r3, PACA_EXSLB+EX_DAR(r13) std r3, _DAR(r1) beq cr6, 2f - li r10, 0x480 /* fix trap number for I-SLB miss */ + li r10, 0x481 /* fix trap number for I-SLB miss */ std r10, _TRAP(r1) 2: bl save_nvgprs addi r3, r1, STACK_FRAME_OVERHEAD -- cgit v1.2.3