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powerpc/pseries: PACA save area fix for MCE vs MCE

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MCE must not enable MSR_RI until PACA_EXMC is no longer being used.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Nicholas Piggin 2016-08-10 20:48:43 +10:00 committed by Benjamin Herrenschmidt
parent 3f3b5dc14c
commit a74599a504
1 changed files with 20 additions and 1 deletions
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21
arch/powerpc/kernel/exceptions-64s.S
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@ -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