Subject: [PATCH v2 41/52] powerpc/tm: update comment about interrupt re-entrancy

From: Nicholas Piggin <[email-masked]>
Date: Thu, 20 Jun 2019 15:14:48 +1000

Since the system reset interrupt began to use its own stack, and
machine check interrupts have done so for some time, r1 can be
changed without clearing MSR[RI], provided no other interrupts
(including SLB misses) are taken.

MSR[RI] does have to be cleared when using SCRATCH0, however.

Signed-off-by: Nicholas Piggin <[email-masked]>
---
 arch/powerpc/kernel/tm.S | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/kernel/tm.S b/arch/powerpc/kernel/tm.S
index 9fabdce255cd..6ba0fdd1e7f8 100644
--- a/arch/powerpc/kernel/tm.S
+++ b/arch/powerpc/kernel/tm.S
@@ -148,7 +148,7 @@ _GLOBAL(tm_reclaim)
 	/* Stash the stack pointer away for use after reclaim */
 	std	r1, PACAR1(r13)
 
-	/* Clear MSR RI since we are about to change r1, EE is already off. */
+	/* Clear MSR RI since we are about to use SCRATCH0, EE is already off */
 	li	r5, 0
 	mtmsrd	r5, 1
 
@@ -474,7 +474,7 @@ restore_gprs:
 
 	REST_GPR(7, r7)
 
-	/* Clear MSR RI since we are about to change r1. EE is already off */
+	/* Clear MSR RI since we are about to use SCRATCH0. EE is already off */
 	li	r5, 0
 	mtmsrd	r5, 1
 
-- 
2.20.1