From a74599a5041979ae83aec7a6d5c8df9131db2ce6 Mon Sep 17 00:00:00 2001 From: Nicholas Piggin Date: Wed, 10 Aug 2016 20:48:43 +1000 Subject: [PATCH] powerpc/pseries: PACA save area fix for MCE vs MCE MCE must not enable MSR_RI until PACA_EXMC is no longer being used. Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/kernel/exceptions-64s.S | 21 ++++++++++++++++++++- 1 file changed, 20 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S index 034b7eaf68d2..bffec73dbffc 100644 --- a/arch/powerpc/kernel/exceptions-64s.S +++ b/arch/powerpc/kernel/exceptions-64s.S @@ -485,7 +485,23 @@ machine_check_fwnmi: EXCEPTION_PROLOG_0(PACA_EXMC) machine_check_pSeries_0: EXCEPTION_PROLOG_1(PACA_EXMC, KVMTEST, 0x200) - EXCEPTION_PROLOG_PSERIES_1(machine_check_common, EXC_STD) + /* + * The following is essentially EXCEPTION_PROLOG_PSERIES_1 with the + * difference that MSR_RI is not enabled, because PACA_EXMC is being + * used, so nested machine check corrupts it. machine_check_common + * enables MSR_RI. + */ + ld r12,PACAKBASE(r13) + ld r10,PACAKMSR(r13) + xori r10,r10,MSR_RI + mfspr r11,SPRN_SRR0 + LOAD_HANDLER(r12, machine_check_common) + mtspr SPRN_SRR0,r12 + mfspr r12,SPRN_SRR1 + mtspr SPRN_SRR1,r10 + rfid + b . /* prevent speculative execution */ + KVM_HANDLER_SKIP(PACA_EXMC, EXC_STD, 0x200) KVM_HANDLER_SKIP(PACA_EXGEN, EXC_STD, 0x300) KVM_HANDLER_SKIP(PACA_EXSLB, EXC_STD, 0x380) @@ -977,6 +993,9 @@ machine_check_common: RECONCILE_IRQ_STATE(r10, r11) ld r3,PACA_EXMC+EX_DAR(r13) lwz r4,PACA_EXMC+EX_DSISR(r13) + /* Enable MSR_RI when finished with PACA_EXMC */ + li r10,MSR_RI + mtmsrd r10,1 std r3,_DAR(r1) std r4,_DSISR(r1) bl save_nvgprs -- 2.30.2