linux-kernel - [PATCH 5.3 009/148] KVM: s390: fix __insn32

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Date:   Thu, 10 Oct 2019 10:34:30 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Christian Borntraeger <borntraeger@...ibm.com>,
        Heiko Carstens <heiko.carstens@...ibm.com>,
        Vasily Gorbik <gor@...ux.ibm.com>
Subject: [PATCH 5.3 009/148] KVM: s390: fix __insn32_query() inline assembly

From: Heiko Carstens <heiko.carstens@...ibm.com>

commit b1c41ac3ce569b04644bb1e3fd28926604637da3 upstream.

The inline assembly constraints of __insn32_query() tell the compiler
that only the first byte of "query" is being written to. Intended was
probably that 32 bytes are written to.

Fix and simplify the code and just use a "memory" clobber.

Fixes: d668139718a9 ("KVM: s390: provide query function for instructions returning 32 byte")
Cc: stable@...r.kernel.org # v5.2+
Acked-by: Christian Borntraeger <borntraeger@...ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@...ibm.com>
Signed-off-by: Vasily Gorbik <gor@...ux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 arch/s390/kvm/kvm-s390.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -332,7 +332,7 @@ static inline int plo_test_bit(unsigned
 	return cc == 0;
 }
 
-static inline void __insn32_query(unsigned int opcode, u8 query[32])
+static inline void __insn32_query(unsigned int opcode, u8 *query)
 {
 	register unsigned long r0 asm("0") = 0;	/* query function */
 	register unsigned long r1 asm("1") = (unsigned long) query;
@@ -340,9 +340,9 @@ static inline void __insn32_query(unsign
 	asm volatile(
 		/* Parameter regs are ignored */
 		"	.insn	rrf,%[opc] << 16,2,4,6,0\n"
-		: "=m" (*query)
+		:
 		: "d" (r0), "a" (r1), [opc] "i" (opcode)
-		: "cc");
+		: "cc", "memory");
 }
 
 #define INSN_SORTL 0xb938