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authorJames Hogan <james.hogan@imgtec.com>2016-08-04 17:36:08 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-08-20 18:11:01 +0200
commitfeaed7c915e47e2c2e13264e1408a64a6736d8f0 (patch)
tree6d4c38772b0037f1df0fb66f37fe3341f1453b79
parent21bc3c38f050caea4a088ac63bd8b2195529ab93 (diff)
downloadlwn-feaed7c915e47e2c2e13264e1408a64a6736d8f0.tar.gz
lwn-feaed7c915e47e2c2e13264e1408a64a6736d8f0.zip
metag: Fix __cmpxchg_u32 asm constraint for CMP
commit 6154c187b97ee7513046bb4eb317a89f738f13ef upstream. The LNKGET based atomic sequence in __cmpxchg_u32 has slightly incorrect constraints for the return value which under certain circumstances can allow an address unit register to be used as the first operand of a CMP instruction. This isn't a valid instruction however as the encodings only allow a data unit to be specified. This would result in an assembler error like the following: Error: failed to assemble instruction: "CMP A0.2,D0Ar6" Fix by changing the constraint from "=&da" (assigned, early clobbered, data or address unit register) to "=&d" (data unit register only). The constraint for the second operand, "bd" (an op2 register where op1 is a data unit register and the instruction supports O2R) is already correct assuming the first operand is a data unit register. Other cases of CMP in inline asm have had their constraints checked, and appear to all be fine. Fixes: 6006c0d8ce94 ("metag: Atomics, locks and bitops") Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: linux-metag@vger.kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--arch/metag/include/asm/cmpxchg_lnkget.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/metag/include/asm/cmpxchg_lnkget.h b/arch/metag/include/asm/cmpxchg_lnkget.h
index 0154e2807ebb..2369ad394876 100644
--- a/arch/metag/include/asm/cmpxchg_lnkget.h
+++ b/arch/metag/include/asm/cmpxchg_lnkget.h
@@ -73,7 +73,7 @@ static inline unsigned long __cmpxchg_u32(volatile int *m, unsigned long old,
" DCACHE [%2], %0\n"
#endif
"2:\n"
- : "=&d" (temp), "=&da" (retval)
+ : "=&d" (temp), "=&d" (retval)
: "da" (m), "bd" (old), "da" (new)
: "cc"
);