linux-kernel - [PATCH for 5.10] powerpc/32s: Fix RTAS machine check with VMAP stack

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <790e46767a5f10ae991969b064682c8c82f96bc3.1610519852.git.christophe.leroy@csgroup.eu>
Date:   Wed, 13 Jan 2021 06:40:20 +0000 (UTC)
From:   Christophe Leroy <christophe.leroy@...roup.eu>
To:     stable@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH for 5.10] powerpc/32s: Fix RTAS machine check with VMAP stack

This is backport for 5.10

(cherry picked from commit 98bf2d3f4970179c702ef64db658e0553bc6ef3a)

When we have VMAP stack, exception prolog 1 sets r1, not r11.

When it is not an RTAS machine check, don't trash r1 because it is
needed by prolog 1.

Fixes: da7bb43ab9da ("powerpc/32: Fix vmap stack - Properly set r1 before activating MMU")
Cc: stable@...r.kernel.org # v5.10+
Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
[mpe: Squash in fixup for RTAS machine check from Christophe]
Signed-off-by: Michael Ellerman <mpe@...erman.id.au>
Link: https://lore.kernel.org/r/bc77d61d1c18940e456a2dee464f1e2eda65a3f0.1608621048.git.christophe.leroy@csgroup.eu
---
 arch/powerpc/kernel/head_book3s_32.S | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/arch/powerpc/kernel/head_book3s_32.S b/arch/powerpc/kernel/head_book3s_32.S
index a0dda2a1f2df..d66da35f2e8d 100644
--- a/arch/powerpc/kernel/head_book3s_32.S
+++ b/arch/powerpc/kernel/head_book3s_32.S
@@ -262,10 +262,19 @@ __secondary_hold_acknowledge:
 MachineCheck:
 	EXCEPTION_PROLOG_0
 #ifdef CONFIG_PPC_CHRP
+#ifdef CONFIG_VMAP_STACK
+	mr	r11, r1
+	mfspr	r1, SPRN_SPRG_THREAD
+	lwz	r1, RTAS_SP(r1)
+	cmpwi	cr1, r1, 0
+	bne	cr1, 7f
+	mr	r1, r11
+#else
 	mfspr	r11, SPRN_SPRG_THREAD
 	lwz	r11, RTAS_SP(r11)
 	cmpwi	cr1, r11, 0
 	bne	cr1, 7f
+#endif
 #endif /* CONFIG_PPC_CHRP */
 	EXCEPTION_PROLOG_1 for_rtas=1
 7:	EXCEPTION_PROLOG_2
-- 
2.25.0