From 74c3354bc1d89d53e8da2dcc6f9f6bfc28b2900f Mon Sep 17 00:00:00 2001 From: Nicholas Piggin Date: Sun, 7 Feb 2021 22:54:12 +1000 Subject: [PATCH] powerpc/pseries/mce: restore msr before returning from handler The pseries real-mode machine check handler can enable the MMU, and return from the handler with the MMU still enabled. This works, but real-mode handler wrapper exit handlers want to rely on the MMU being in real-mode. So change the pseries handler to restore the MSR after it has finished virtual mode tasks. Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/1612702361.lm7fqo56re.astroid@bobo.none --- arch/powerpc/platforms/pseries/ras.c | 19 +++++++++++++++---- 1 file changed, 15 insertions(+), 4 deletions(-) diff --git a/arch/powerpc/platforms/pseries/ras.c b/arch/powerpc/platforms/pseries/ras.c index 92c08fe893cf..f8b390a9d9fb 100644 --- a/arch/powerpc/platforms/pseries/ras.c +++ b/arch/powerpc/platforms/pseries/ras.c @@ -717,6 +717,7 @@ static int mce_handle_error(struct pt_regs *regs, struct rtas_error_log *errp) struct pseries_errorlog *pseries_log; struct pseries_mc_errorlog *mce_log = NULL; int disposition = rtas_error_disposition(errp); + unsigned long msr; u8 error_type; if (!rtas_error_extended(errp)) @@ -742,9 +743,21 @@ static int mce_handle_error(struct pt_regs *regs, struct rtas_error_log *errp) * SLB multihit is done by now. */ out: - mtmsr(mfmsr() | MSR_IR | MSR_DR); + msr = mfmsr(); + mtmsr(msr | MSR_IR | MSR_DR); + disposition = mce_handle_err_virtmode(regs, errp, mce_log, disposition); + + /* + * Queue irq work to log this rtas event later. + * irq_work_queue uses per-cpu variables, so do this in virt + * mode as well. + */ + irq_work_queue(&mce_errlog_process_work); + + mtmsr(msr); + return disposition; } @@ -860,10 +873,8 @@ long pseries_machine_check_realmode(struct pt_regs *regs) * virtual mode. */ disposition = mce_handle_error(regs, errp); - fwnmi_release_errinfo(); - /* Queue irq work to log this rtas event later. */ - irq_work_queue(&mce_errlog_process_work); + fwnmi_release_errinfo(); if (disposition == RTAS_DISP_FULLY_RECOVERED) return 1; -- 2.20.1