powerpc/64s/exception: machine check use correct cfar for late handler

Bare metal machine checks run an "early" handler in real mode before
running the main handler which reports the event.

The main handler runs exactly as a normal interrupt handler, after the
"windup" which sets registers back as they were at interrupt entry.
CFAR does not get restored by the windup code, so that will be wrong
when the handler is run.

Restore the CFAR to the saved value before running the late handler.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190802105709.27696-8-npiggin@gmail.com
This commit is contained in:
Nicholas Piggin 2019-08-02 20:56:32 +10:00 committed by Michael Ellerman
parent fa2760eca5
commit 0b66370c61
1 changed files with 4 additions and 0 deletions

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@ -1186,6 +1186,10 @@ FTR_SECTION_ELSE
ALT_FTR_SECTION_END_IFSET(CPU_FTR_HVMODE)
9:
/* Deliver the machine check to host kernel in V mode. */
BEGIN_FTR_SECTION
ld r10,ORIG_GPR3(r1)
mtspr SPRN_CFAR,r10
END_FTR_SECTION_IFSET(CPU_FTR_CFAR)
MACHINE_CHECK_HANDLER_WINDUP
EXCEPTION_PROLOG_0 PACA_EXMC
EXCEPTION_PROLOG_1 EXC_STD, PACA_EXMC, 1, 0x200, 1, 1, 0