* [PATCH] xtensa: fix a7 clobbering in coprocessor context load/store
@ 2022-04-16 1:50 Max Filippov
0 siblings, 0 replies; only message in thread
From: Max Filippov @ 2022-04-16 1:50 UTC (permalink / raw)
To: linux-xtensa; +Cc: Chris Zankel, linux-kernel, Max Filippov, stable
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
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2022-04-16 1:50 [PATCH] xtensa: fix a7 clobbering in coprocessor context load/store Max Filippov
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