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.
Signed-off-by: Paul Mackerras <pau...@samba.org>
---
arch/powerpc/kernel/exceptions-64s.S | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/arch/powerpc/kernel/exceptions-64s.S
b/arch/powerpc/kernel/exceptions-64s.S
index e3c8a03..3e06b26 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -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)
--
1.8.4.rc2
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