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| author |   Nicholas Piggin <npiggin@gmail.com> | 2019-02-26 18:51:10 +1000 |
|---|---|---|
| committer |   Michael Ellerman <mpe@ellerman.id.au> | 2019-02-26 23:28:26 +1100 |
| commit | 38555434a910a657ba6d7d06a4fe0376c8b04685 (patch) | |
| tree | cd1b893915eff74c542d57bc3187e59bebdf22cb /arch/powerpc/kernel | |
| parent | powerpc/64s: Prepare to handle data interrupts vs d-side MCE reentrancy (diff) | |
| download | linux-dev-38555434a910a657ba6d7d06a4fe0376c8b04685.tar.xz linux-dev-38555434a910a657ba6d7d06a4fe0376c8b04685.zip | |
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>
Diffstat (limited to 'arch/powerpc/kernel')
| -rw-r--r-- | arch/powerpc/kernel/exceptions-64s.S | 36 |
1 files changed, 26 insertions, 10 deletions
diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S index 680197df4aea..99312328ee66 100644 --- a/arch/powerpc/kernel/exceptions-64s.S +++ b/arch/powerpc/kernel/exceptions-64s.S @@ -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) |