From 8660eadce2bafd16b2b2d0100190c5ac76519caf Mon Sep 17 00:00:00 2001 From: James Hogan Date: Thu, 4 Aug 2016 17:36:08 +0100 Subject: [PATCH] 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 Cc: linux-metag@vger.kernel.org Signed-off-by: Greg Kroah-Hartman --- arch/metag/include/asm/cmpxchg_lnkget.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/metag/include/asm/cmpxchg_lnkget.h b/arch/metag/include/asm/cmpxchg_lnkget.h index 0154e28..2369ad3 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" ); -- 2.7.4