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powerpc/64s: Fix data interrupts vs d-side MCE reentrancy 

Handlers for interrupts that set DAR / DSISR, set MSR[RI] before those
SPRs are read. If a d-side machine check hits in this window, DAR /
DSISR will be clobbered silently, leading to random corruption.

Fix this by having handlers save those registers before setting MSR[RI].

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Nicholas Piggin 2019-02-26 18:51:10 +10:00 committed by Michael Ellerman
parent e779fc9364
commit 38555434a9
1 changed files with 26 additions and 10 deletions
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36
arch/powerpc/kernel/exceptions-64s.S
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@ -582,12 +582,25 @@ EXC_REAL_END(data_access, 0x300, 0x80)
TRAMP_REAL_BEGIN(tramp_real_data_access)
EXCEPTION_PROLOG_1(PACA_EXGEN, KVMTEST_PR, 0x300)
/*
* DAR/DSISR must be read before setting MSR[RI], because
* a d-side MCE will clobber those registers so is not
* recoverable if they are live.
*/
mfspr r10,SPRN_DAR
mfspr r11,SPRN_DSISR
std r10,PACA_EXGEN+EX_DAR(r13)
stw r11,PACA_EXGEN+EX_DSISR(r13)
EXCEPTION_PROLOG_2(data_access_common, EXC_STD)
EXC_VIRT_BEGIN(data_access, 0x4300, 0x80)
SET_SCRATCH0(r13) /* save r13 */
EXCEPTION_PROLOG_0(PACA_EXGEN)
EXCEPTION_PROLOG_1(PACA_EXGEN, NOTEST, 0x300)
mfspr r10,SPRN_DAR
mfspr r11,SPRN_DSISR
std r10,PACA_EXGEN+EX_DAR(r13)
stw r11,PACA_EXGEN+EX_DSISR(r13)
EXCEPTION_PROLOG_2_RELON(data_access_common, EXC_STD)
EXC_VIRT_END(data_access, 0x4300, 0x80)
@ -598,11 +611,8 @@ EXC_COMMON_BEGIN(data_access_common)
* Here r13 points to the paca, r9 contains the saved CR,
* SRR0 and SRR1 are saved in r11 and r12,
* r9 - r13 are saved in paca->exgen.
* EX_DAR and EX_DSISR have saved DAR/DSISR
*/
mfspr r10,SPRN_DAR
std r10,PACA_EXGEN+EX_DAR(r13)
mfspr r10,SPRN_DSISR
stw r10,PACA_EXGEN+EX_DSISR(r13)
EXCEPTION_PROLOG_COMMON(0x300, PACA_EXGEN)
RECONCILE_IRQ_STATE(r10, r11)
ld r12,_MSR(r1)
@ -626,20 +636,22 @@ EXC_REAL_END(data_access_slb, 0x380, 0x80)
TRAMP_REAL_BEGIN(tramp_real_data_access_slb)
EXCEPTION_PROLOG_1(PACA_EXSLB, KVMTEST_PR, 0x380)
mfspr r10,SPRN_DAR
std r10,PACA_EXSLB+EX_DAR(r13)
EXCEPTION_PROLOG_2(data_access_slb_common, EXC_STD)
EXC_VIRT_BEGIN(data_access_slb, 0x4380, 0x80)
SET_SCRATCH0(r13) /* save r13 */
EXCEPTION_PROLOG_0(PACA_EXSLB)
EXCEPTION_PROLOG_1(PACA_EXSLB, NOTEST, 0x380)
mfspr r10,SPRN_DAR
std r10,PACA_EXSLB+EX_DAR(r13)
EXCEPTION_PROLOG_2_RELON(data_access_slb_common, EXC_STD)
EXC_VIRT_END(data_access_slb, 0x4380, 0x80)
TRAMP_KVM_SKIP(PACA_EXSLB, 0x380)
EXC_COMMON_BEGIN(data_access_slb_common)
mfspr r10,SPRN_DAR
std r10,PACA_EXSLB+EX_DAR(r13)
EXCEPTION_PROLOG_COMMON(0x380, PACA_EXSLB)
ld r4,PACA_EXSLB+EX_DAR(r13)
std r4,_DAR(r1)
@ -739,6 +751,10 @@ EXC_REAL_BEGIN(alignment, 0x600, 0x100)
SET_SCRATCH0(r13) /* save r13 */
EXCEPTION_PROLOG_0(PACA_EXGEN)
EXCEPTION_PROLOG_1(PACA_EXGEN, KVMTEST_PR, 0x600)
mfspr r10,SPRN_DAR
mfspr r11,SPRN_DSISR
std r10,PACA_EXGEN+EX_DAR(r13)
stw r11,PACA_EXGEN+EX_DSISR(r13)
EXCEPTION_PROLOG_2(alignment_common, EXC_STD)
EXC_REAL_END(alignment, 0x600, 0x100)
@ -746,15 +762,15 @@ EXC_VIRT_BEGIN(alignment, 0x4600, 0x100)
SET_SCRATCH0(r13) /* save r13 */
EXCEPTION_PROLOG_0(PACA_EXGEN)
EXCEPTION_PROLOG_1(PACA_EXGEN, NOTEST, 0x600)
mfspr r10,SPRN_DAR
mfspr r11,SPRN_DSISR
std r10,PACA_EXGEN+EX_DAR(r13)
stw r11,PACA_EXGEN+EX_DSISR(r13)
EXCEPTION_PROLOG_2_RELON(alignment_common, EXC_STD)
EXC_VIRT_END(alignment, 0x4600, 0x100)
TRAMP_KVM(PACA_EXGEN, 0x600)
EXC_COMMON_BEGIN(alignment_common)
mfspr r10,SPRN_DAR
std r10,PACA_EXGEN+EX_DAR(r13)
mfspr r10,SPRN_DSISR
stw r10,PACA_EXGEN+EX_DSISR(r13)
EXCEPTION_PROLOG_COMMON(0x600, PACA_EXGEN)
ld r3,PACA_EXGEN+EX_DAR(r13)
lwz r4,PACA_EXGEN+EX_DSISR(r13)