[PATCH AUTOSEL 5.10 16/47] powerpc: improve handling of unrecoverable system reset

Sasha Levin
2021-03-02T16:09:15Z

From: Nicholas Piggin <npiggin@gmail.com>

[ Upstream commit 11cb0a25f71818ca7ab4856548ecfd83c169aa4d ]

If an unrecoverable system reset hits in process context, the system
does not have to panic. Similar to machine check, call nmi_exit()
before die().

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210130130852.2952424-26-npiggin@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/powerpc/kernel/traps.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index 5006dcbe1d9f..77dffea3d537 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -509,8 +509,11 @@ out:
die("Unrecoverable nested System Reset", regs, SIGABRT);
#endif
/* Must die if the interrupt is not recoverable */
- if (!(regs->msr & MSR_RI))
+ if (!(regs->msr & MSR_RI)) {
+ /* For the reason explained in die_mce, nmi_exit before die */
+ nmi_exit();
die("Unrecoverable System Reset", regs, SIGABRT);
+ }

if (saved_hsrrs) {
mtspr(SPRN_HSRR0, hsrr0);
--
2.30.1