From: Max Filippov <jcmvbkbc@gmail.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org, linux-xtensa@linux-xtensa.org,
Chris Zankel <chris@zankel.net>,
Max Filippov <jcmvbkbc@gmail.com>,
stable@vger.kernel.org
Subject: [PATCH 3/3] xtensa: fix a7 clobbering in coprocessor context load/store
Date: Tue, 19 Apr 2022 23:16:11 -0700 [thread overview]
Message-ID: <20220420061611.4103443-4-jcmvbkbc@gmail.com> (raw)
In-Reply-To: <20220420061611.4103443-1-jcmvbkbc@gmail.com>
Fast coprocessor exception handler saves a3..a6, but coprocessor context
load/store code uses a4..a7 as temporaries, potentially clobbering a7.
'Potentially' because coprocessor state load/store macros may not use
all four temporary registers (and neither FPU nor HiFi macros do).
Use a3..a6 as intended.
Cc: stable@vger.kernel.org
Fixes: c658eac628aa ("[XTENSA] Add support for configurable registers and coprocessors")
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
---
arch/xtensa/kernel/coprocessor.S | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/xtensa/kernel/coprocessor.S b/arch/xtensa/kernel/coprocessor.S
index 45cc0ae0af6f..c7b9f12896f2 100644
--- a/arch/xtensa/kernel/coprocessor.S
+++ b/arch/xtensa/kernel/coprocessor.S
@@ -29,7 +29,7 @@
.if XTENSA_HAVE_COPROCESSOR(x); \
.align 4; \
.Lsave_cp_regs_cp##x: \
- xchal_cp##x##_store a2 a4 a5 a6 a7; \
+ xchal_cp##x##_store a2 a3 a4 a5 a6; \
jx a0; \
.endif
@@ -46,7 +46,7 @@
.if XTENSA_HAVE_COPROCESSOR(x); \
.align 4; \
.Lload_cp_regs_cp##x: \
- xchal_cp##x##_load a2 a4 a5 a6 a7; \
+ xchal_cp##x##_load a2 a3 a4 a5 a6; \
jx a0; \
.endif
--
2.30.2
next prev parent reply other threads:[~2022-04-20 6:16 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-20 6:16 [PULL 0/3] xtensa fixes for 5.18 Max Filippov
2022-04-20 6:16 ` [PATCH 1/3] xtensa: patch_text: Fixup last cpu should be master Max Filippov
2022-04-20 6:16 ` [PATCH 2/3] arch: xtensa: platforms: Fix deadlock in rs_close() Max Filippov
2022-04-20 6:16 ` Max Filippov [this message]
2022-04-20 20:00 ` [PULL 0/3] xtensa fixes for 5.18 pr-tracker-bot
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