powerpc: Fix denormalized exception handler
PATCH 1/1 powerpc: Fix denormalized exception handler
The denormalized exception handler (denorm_exception_hv) has a couple of bugs. If the CONFIG_PPC_DENORMALISATION option is not selected, or the HSRR1_DENORM bit is not set in HSRR1, we don't test whether the interrupt occurred within a KVM guest. On the other hand, if the HSRR1_DENORM bit is set and CONFIG_PPC_DENORMALISATION is enabled, we corrupt the CFAR and PPR.
To correct these problems, this replaces the open-coded version of EXCEPTION_PROLOG_1 that is there currently, and that is missing the saving of PPR and CFAR values to the PACA, with an instance of EXCEPTION_PROLOG_1. This adds an explicit KVMTEST after testing whether the exception is one we can handle, and adds code to restore the CFAR on exit.
--- arch/powerpc/kernel/exceptions-64s.S | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-)
arch/powerpc/kernel/exceptions-64s.S +6 -5
@@ -360,11 +360,7 @@ denorm_exception_hv: HMT_MEDIUM_PPR_DISCARD mtspr SPRN_SPRG_HSCRATCH0,r13 EXCEPTION_PROLOG_0(PACA_EXGEN) - std r11,PACA_EXGEN+EX_R11(r13) - std r12,PACA_EXGEN+EX_R12(r13) - mfspr r9,SPRN_SPRG_HSCRATCH0 - std r9,PACA_EXGEN+EX_R13(r13) - mfcr r9 + EXCEPTION_PROLOG_1(PACA_EXGEN, NOTEST, 0x1500) #ifdef CONFIG_PPC_DENORMALISATION mfspr r10,SPRN_HSRR1
@@ -374,6 +370,7 @@ denorm_exception_hv: bne+ denorm_assist #endif + KVMTEST(0x1500) EXCEPTION_PROLOG_PSERIES_1(denorm_common, EXC_HV) KVM_HANDLER_SKIP(PACA_EXGEN, EXC_STD, 0x1500)
@@ -494,6 +491,10 @@ denorm_done: mtcrf 0x80,r9 ld r9,PACA_EXGEN+EX_R9(r13) RESTORE_PPR_PACA(PACA_EXGEN, r10) +BEGIN_FTR_SECTION + ld r10,PACA_EXGEN+EX_CFAR(r13) + mtspr SPRN_CFAR,r10 +END_FTR_SECTION_IFSET(CPU_FTR_CFAR) ld r10,PACA_EXGEN+EX_R10(r13) ld r11,PACA_EXGEN+EX_R11(r13) ld r12,PACA_EXGEN+EX_R12(r13)
Signature · 1 line
1.8.4.rc2