From d410ae2126481a74bc5be4a6242c4a232c19a984 Mon Sep 17 00:00:00 2001 From: Mahesh Salgaonkar Date: Tue, 11 Mar 2014 10:56:18 +0530 Subject: [PATCH] powerpc/book3s: Fix CFAR clobbering issue in machine check handler. While checking powersaving mode in machine check handler at 0x200, we clobber CFAR register. Fix it by saving and restoring it during beq/bgt. Signed-off-by: Mahesh Salgaonkar Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/include/asm/exception-64s.h | 8 ++++++++ arch/powerpc/kernel/exceptions-64s.S | 5 +++++ 2 files changed, 13 insertions(+) diff --git a/arch/powerpc/include/asm/exception-64s.h b/arch/powerpc/include/asm/exception-64s.h index 6683061..aeaa56c 100644 --- a/arch/powerpc/include/asm/exception-64s.h +++ b/arch/powerpc/include/asm/exception-64s.h @@ -147,6 +147,14 @@ BEGIN_FTR_SECTION_NESTED(943) \ END_FTR_SECTION_NESTED(ftr,ftr,943) /* + * Set an SPR from a register if the CPU has the given feature + */ +#define OPT_SET_SPR(ra, spr, ftr) \ +BEGIN_FTR_SECTION_NESTED(943) \ + mtspr spr,ra; \ +END_FTR_SECTION_NESTED(ftr,ftr,943) + +/* * Save a register to the PACA if the CPU has the given feature */ #define OPT_SAVE_REG_TO_PACA(offset, ra, ftr) \ diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S index 38d5073..4c34c3c 100644 --- a/arch/powerpc/kernel/exceptions-64s.S +++ b/arch/powerpc/kernel/exceptions-64s.S @@ -164,13 +164,18 @@ BEGIN_FTR_SECTION */ mfspr r13,SPRN_SRR1 rlwinm. r13,r13,47-31,30,31 + OPT_GET_SPR(r13, SPRN_CFAR, CPU_FTR_CFAR) beq 9f + mfspr r13,SPRN_SRR1 + rlwinm. r13,r13,47-31,30,31 /* waking up from powersave (nap) state */ cmpwi cr1,r13,2 /* Total loss of HV state is fatal. let's just stay stuck here */ + OPT_GET_SPR(r13, SPRN_CFAR, CPU_FTR_CFAR) bgt cr1,. 9: + OPT_SET_SPR(r13, SPRN_CFAR, CPU_FTR_CFAR) END_FTR_SECTION_IFSET(CPU_FTR_HVMODE | CPU_FTR_ARCH_206) #endif /* CONFIG_PPC_P7_NAP */ EXCEPTION_PROLOG_0(PACA_EXMC) -- 2.7.4