From: Nicholas Piggin Date: Fri, 23 Mar 2018 05:53:38 +0000 (+1000) Subject: powerpc/64s: Fix i-side SLB miss bad address handler saving nonvolatile GPRs X-Git-Tag: v4.14.33~52 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=0726ba0491ca3e6e6bd88b332c0fcfda7aedd48f;p=platform%2Fkernel%2Flinux-rpi.git 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 --- diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S index e91b40aa5417..f9ca4bb3d48e 100644 --- a/arch/powerpc/kernel/exceptions-64s.S +++ b/arch/powerpc/kernel/exceptions-64s.S @@ -704,7 +704,7 @@ 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