From e2a8b49e79553bd8ec48f73cead84e6146c09408 Mon Sep 17 00:00:00 2001
From: Michael Ellerman <mpe@ellerman.id.au>
Date: Thu, 7 May 2020 22:33:24 +1000
Subject: [PATCH] powerpc/uaccess: Don't use "m<>" constraint
References: jsc#SLE-9246
Patch-mainline: v5.8-rc1
Git-commit: e2a8b49e79553bd8ec48f73cead84e6146c09408
The "m<>" constraint breaks compilation with GCC 4.6.x era compilers.
The use of the constraint allows the compiler to use update-form
instructions, however in practice current compilers never generate
those forms for any of the current uses of __put_user_asm_goto().
We anticipate that GCC 4.6 will be declared unsupported for building
the kernel in the not too distant future. So for now just switch to
the "m" constraint.
Fixes: 334710b1496a ("powerpc/uaccess: Implement unsafe_put_user() using 'asm goto'")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Segher Boessenkool <segher@kernel.crashing.org>
Link: https://lore.kernel.org/r/20200507123324.2250024-1-mpe@ellerman.id.au
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
arch/powerpc/include/asm/uaccess.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/uaccess.h
index 62cc8d7640ec..164112007f54 100644
--- a/arch/powerpc/include/asm/uaccess.h
+++ b/arch/powerpc/include/asm/uaccess.h
@@ -210,7 +210,7 @@ do { \
"1: " op "%U1%X1 %0,%1 # put_user\n" \
EX_TABLE(1b, %l2) \
: \
- : "r" (x), "m<>" (*addr) \
+ : "r" (x), "m" (*addr) \
: \
: label)
--
2.28.0