From: Nicholas Piggin npiggin@gmail.com
[ Upstream commit 0b66370c61fcf5fcc1d6901013e110284da6e2bb ]
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 Signed-off-by: Sasha Levin sashal@kernel.org --- arch/powerpc/kernel/exceptions-64s.S | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S index 6c51aa845bcee..3e564536a237f 100644 --- a/arch/powerpc/kernel/exceptions-64s.S +++ b/arch/powerpc/kernel/exceptions-64s.S @@ -556,6 +556,10 @@ 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 SET_SCRATCH0(r13) /* save r13 */ EXCEPTION_PROLOG_0(PACA_EXMC)