From: Nicholas Piggin <npiggin@gmail.com>
Date: Mon, 1 May 2017 12:01:10 +0000 (+1000)
Subject: powerpc/64s: Fix OPAL_CALL non-maskable interrupt reentrancy
X-Git-Tag: v4.13-rc1~111^2~157
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=c07e1b8a27a1419cdd4af7a1def26d12bb24d2b1;p=linux.git

powerpc/64s: Fix OPAL_CALL non-maskable interrupt reentrancy

OPAL_CALL uses SRR[01] with MSR_RI=1, which gets corrupted if there
is an interleaving system reset or machine check interrupt.

Use HSRR[01] instead, which does not require MSR_RI=0.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---

diff --git a/arch/powerpc/platforms/powernv/opal-wrappers.S b/arch/powerpc/platforms/powernv/opal-wrappers.S
index f620572f891f..4ca6c26a56d5 100644
--- a/arch/powerpc/platforms/powernv/opal-wrappers.S
+++ b/arch/powerpc/platforms/powernv/opal-wrappers.S
@@ -99,10 +99,10 @@ opal_return:
 	lwz	r4,8(r1);
 	ld	r5,PPC_LR_STKOFF(r1);
 	ld	r6,PACASAVEDMSR(r13);
-	mtspr	SPRN_SRR0,r5;
-	mtspr	SPRN_SRR1,r6;
 	mtcr	r4;
-	rfid
+	mtspr	SPRN_HSRR0,r5;
+	mtspr	SPRN_HSRR1,r6;
+	hrfid
 
 opal_real_call:
 	mfcr	r11