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Date:   Fri, 08 May 2020 09:57:40 -0700
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Subject: Re: [PATCH] x86: Use RDRAND and RDSEED mnemonics in archrandom.h
To:     Uros Bizjak <ubizjak@gmail.com>, x86@kernel.org,
        linux-kernel@vger.kernel.org
CC:     Ingo Molnar <mingo@redhat.com>,
        Thomas Gleixner <tglx@linutronix.de>
From:   hpa@zytor.com
Message-ID: <BACCC7C6-D456-4FAF-A11B-213995FE356A@zytor.com>
Sender: linux-kernel-owner@vger.kernel.org
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On May 8, 2020 3:58:17 AM PDT, Uros Bizjak <ubizjak@gmail=2Ecom> wrote:
>Current minimum required version of binutils is 2=2E23,
>which supports RDRAND and RDSEED instruction mnemonics=2E
>
>Replace the byte-wise specification of RDRAND and
>RDSEED with these proper mnemonics=2E
>
>Signed-off-by: Uros Bizjak <ubizjak@gmail=2Ecom>
>CC: "H=2E Peter Anvin" <hpa@zytor=2Ecom>
>CC: Ingo Molnar <mingo@redhat=2Ecom>
>CC: Thomas Gleixner <tglx@linutronix=2Ede>
>---
> arch/x86/include/asm/archrandom=2Eh | 26 ++++++++------------------
> 1 file changed, 8 insertions(+), 18 deletions(-)
>
>diff --git a/arch/x86/include/asm/archrandom=2Eh
>b/arch/x86/include/asm/archrandom=2Eh
>index 7a4bb1bd4bdb=2E=2Eebc248e49549 100644
>--- a/arch/x86/include/asm/archrandom=2Eh
>+++ b/arch/x86/include/asm/archrandom=2Eh
>@@ -15,16 +15,6 @@
>=20
> #define RDRAND_RETRY_LOOPS	10
>=20
>-#define RDRAND_INT	"=2Ebyte 0x0f,0xc7,0xf0"
>-#define RDSEED_INT	"=2Ebyte 0x0f,0xc7,0xf8"
>-#ifdef CONFIG_X86_64
>-# define RDRAND_LONG	"=2Ebyte 0x48,0x0f,0xc7,0xf0"
>-# define RDSEED_LONG	"=2Ebyte 0x48,0x0f,0xc7,0xf8"
>-#else
>-# define RDRAND_LONG	RDRAND_INT
>-# define RDSEED_LONG	RDSEED_INT
>-#endif
>-
> /* Unconditional execution of RDRAND and RDSEED */
>=20
> 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 =3D RDRAND_RETRY_LOOPS;
> 	do {
>-		asm volatile(RDRAND_LONG
>+		asm volatile("rdrand %[out]"
> 			     CC_SET(c)
>-			     : CC_OUT(c) (ok), "=3Da" (*v));
>+			     : CC_OUT(c) (ok), [out] "=3Dr" (*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 =3D RDRAND_RETRY_LOOPS;
> 	do {
>-		asm volatile(RDRAND_INT
>+		asm volatile("rdrand %[out]"
> 			     CC_SET(c)
>-			     : CC_OUT(c) (ok), "=3Da" (*v));
>+			     : CC_OUT(c) (ok), [out] "=3Dr" (*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), "=3Da" (*v));
>+		     : CC_OUT(c) (ok), [out] "=3Dr" (*v));
> 	return ok;
> }
>=20
> 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), "=3Da" (*v));
>+		     : CC_OUT(c) (ok), [out] "=3Dr" (*v));
> 	return ok;
> }
>=20

Reviewed-by: H=2E Peter Anvin (Intel) <hpa@zytor=2Ecom>
--=20
Sent from my Android device with K-9 Mail=2E Please excuse my brevity=2E