Subject: [PATCH v6 21/39] powerpc/mce: ensure machine check handler always tests RI

From: Nicholas Piggin <[email-masked]>
Date: Sat, 16 Jan 2021 02:49:54 +1000

A machine check that is handled must still check MSR[RI] for
recoverability of the interrupted context. Without this patch
it's possible for a handled machine check to return to a
context where it has clobbered live registers.

Signed-off-by: Nicholas Piggin <[email-masked]>
---
 arch/powerpc/kernel/traps.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index f9ef183a5454..3a8699995a77 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -846,11 +846,11 @@ void machine_check_exception(struct pt_regs *regs)
 
 	die_mce("Machine check", regs, SIGBUS);
 
+bail:
 	/* Must die if the interrupt is not recoverable */
 	if (!(regs->msr & MSR_RI))
 		die_mce("Unrecoverable Machine check", regs, SIGBUS);
 
-bail:
 	if (nmi) nmi_exit();
 }
 NOKPROBE_SYMBOL(machine_check_exception);
-- 
2.23.0