Commit 74c3354b authored by Nicholas Piggin's avatar Nicholas Piggin Committed by Michael Ellerman
Browse files

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: default avatarNicholas Piggin <npiggin@gmail.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1612702361.lm7fqo56re.astroid@bobo.none
parent 56acfdd8

arch/powerpc/platforms/pseries/ras.c

+15 −4
Original line number Original line Diff line number Diff line
@@ -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_errorlog *pseries_log;

	struct pseries_mc_errorlog *mce_log = NULL;

	struct pseries_mc_errorlog *mce_log = NULL;

	int disposition = rtas_error_disposition(errp);

	int disposition = rtas_error_disposition(errp);

	unsigned long msr;

	u8 error_type;

	u8 error_type;





	if (!rtas_error_extended(errp))

	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.

	 *       SLB multihit is done by now.

	 */

	 */

out:

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 = mce_handle_err_virtmode(regs, errp, mce_log,

					      disposition);

					      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;

	return disposition;

}

}
@@ -860,10 +873,8 @@ long pseries_machine_check_realmode(struct pt_regs *regs) 
		 * virtual mode.

		 * virtual mode.

		 */

		 */

		disposition = mce_handle_error(regs, errp);

		disposition = mce_handle_error(regs, errp);

		fwnmi_release_errinfo();





		/* Queue irq work to log this rtas event later. */

		fwnmi_release_errinfo();

		irq_work_queue(&mce_errlog_process_work);





		if (disposition == RTAS_DISP_FULLY_RECOVERED)

		if (disposition == RTAS_DISP_FULLY_RECOVERED)

			return 1;

			return 1;