linux-kernel - [tip: x86/cpu] x86/cpu: Use RDRAND and RDSEED mnemonics in archrandom.h

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Message-ID: <158982516602.17951.15035547991791218308.tip-bot2@tip-bot2>
Date:   Mon, 18 May 2020 18:06:06 -0000
From:   "tip-bot2 for Uros Bizjak" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Uros Bizjak <ubizjak@...il.com>, Borislav Petkov <bp@...e.de>,
        "H. Peter Anvin (Intel)" <hpa@...or.com>,
        "Peter Zijlstra (Intel)" <peterz@...radead.org>,
        x86 <x86@...nel.org>, LKML <linux-kernel@...r.kernel.org>
Subject: [tip: x86/cpu] x86/cpu: Use RDRAND and RDSEED mnemonics in archrandom.h

The following commit has been merged into the x86/cpu branch of tip:

Commit-ID:     3d81b3d1e55a518837c3d1f722c6d93abe34aa85
Gitweb:        https://git.kernel.org/tip/3d81b3d1e55a518837c3d1f722c6d93abe34aa85
Author:        Uros Bizjak <ubizjak@...il.com>
AuthorDate:    Fri, 08 May 2020 12:58:17 +02:00
Committer:     Borislav Petkov <bp@...e.de>
CommitterDate: Mon, 18 May 2020 19:50:47 +02:00

x86/cpu: Use RDRAND and RDSEED mnemonics in archrandom.h

Current minimum required version of binutils is 2.23,
which supports RDRAND and RDSEED instruction mnemonics.

Replace the byte-wise specification of RDRAND and
RDSEED with these proper mnemonics.

Signed-off-by: Uros Bizjak <ubizjak@...il.com>
Signed-off-by: Borislav Petkov <bp@...e.de>
Reviewed-by: H. Peter Anvin (Intel) <hpa@...or.com>
Acked-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Link: https://lkml.kernel.org/r/20200508105817.207887-1-ubizjak@gmail.com
---
 arch/x86/include/asm/archrandom.h | 26 ++++++++------------------
 1 file changed, 8 insertions(+), 18 deletions(-)

diff --git a/arch/x86/include/asm/archrandom.h b/arch/x86/include/asm/archrandom.h
index 7a4bb1b..ebc248e 100644
--- a/arch/x86/include/asm/archrandom.h
+++ b/arch/x86/include/asm/archrandom.h
@@ -15,16 +15,6 @@
 
 #define RDRAND_RETRY_LOOPS	10
 
-#define RDRAND_INT	".byte 0x0f,0xc7,0xf0"
-#define RDSEED_INT	".byte 0x0f,0xc7,0xf8"
-#ifdef CONFIG_X86_64
-# define RDRAND_LONG	".byte 0x48,0x0f,0xc7,0xf0"
-# define RDSEED_LONG	".byte 0x48,0x0f,0xc7,0xf8"
-#else
-# define RDRAND_LONG	RDRAND_INT
-# define RDSEED_LONG	RDSEED_INT
-#endif
-
 /* Unconditional execution of RDRAND and RDSEED */
 
 static inline bool __must_check rdrand_long(unsigned long *v)
@@ -32,9 +22,9 @@ static inline bool __must_check rdrand_long(unsigned long *v)
 	bool ok;
 	unsigned int retry = RDRAND_RETRY_LOOPS;
 	do {
-		asm volatile(RDRAND_LONG
+		asm volatile("rdrand %[out]"
 			     CC_SET(c)
-			     : CC_OUT(c) (ok), "=a" (*v));
+			     : CC_OUT(c) (ok), [out] "=r" (*v));
 		if (ok)
 			return true;
 	} while (--retry);
@@ -46,9 +36,9 @@ static inline bool __must_check rdrand_int(unsigned int *v)
 	bool ok;
 	unsigned int retry = RDRAND_RETRY_LOOPS;
 	do {
-		asm volatile(RDRAND_INT
+		asm volatile("rdrand %[out]"
 			     CC_SET(c)
-			     : CC_OUT(c) (ok), "=a" (*v));
+			     : CC_OUT(c) (ok), [out] "=r" (*v));
 		if (ok)
 			return true;
 	} while (--retry);
@@ -58,18 +48,18 @@ static inline bool __must_check rdrand_int(unsigned int *v)
 static inline bool __must_check rdseed_long(unsigned long *v)
 {
 	bool ok;
-	asm volatile(RDSEED_LONG
+	asm volatile("rdseed %[out]"
 		     CC_SET(c)
-		     : CC_OUT(c) (ok), "=a" (*v));
+		     : CC_OUT(c) (ok), [out] "=r" (*v));
 	return ok;
 }
 
 static inline bool __must_check rdseed_int(unsigned int *v)
 {
 	bool ok;
-	asm volatile(RDSEED_INT
+	asm volatile("rdseed %[out]"
 		     CC_SET(c)
-		     : CC_OUT(c) (ok), "=a" (*v));
+		     : CC_OUT(c) (ok), [out] "=r" (*v));
 	return ok;
 }