From 259acc5c255a4260b3db0461afd5d93fabfe8524 Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Sat, 10 Dec 2016 10:37:32 +0100 Subject: [PATCH] s390/cpumf: fix qsi inline assembly The qsi inline assembly takes an initialized "cc" variable as output operand but specifies it as write-to operand only instead of read/write operand. This allows the compiler to omit the initialization, which in fact it also does (gcc 6.1). Use the "+" constraint modifier to fix this. In addition also use the Q constraint to specify the hws_qsi_info_block memory location, so the compiler can generate slightly better code. Also get rid of the cc clobber since none of the instructions within the inline assembly modify the condition code. Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky --- arch/s390/include/asm/cpu_mf.h | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-) diff --git a/arch/s390/include/asm/cpu_mf.h b/arch/s390/include/asm/cpu_mf.h index b69d8bc..428c412 100644 --- a/arch/s390/include/asm/cpu_mf.h +++ b/arch/s390/include/asm/cpu_mf.h @@ -213,18 +213,14 @@ static inline int stcctm5(u64 num, u64 *val) /* Query sampling information */ static inline int qsi(struct hws_qsi_info_block *info) { - int cc; - cc = 1; + int cc = 1; asm volatile( - "0: .insn s,0xb2860000,0(%1)\n" + "0: .insn s,0xb2860000,%1\n" "1: lhi %0,0\n" "2:\n" EX_TABLE(0b, 2b) EX_TABLE(1b, 2b) - : "=d" (cc), "+a" (info) - : "m" (*info) - : "cc", "memory"); - + : "+d" (cc), "+Q" (*info)); return cc ? -EINVAL : 0; } -- 2.7.4