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@gmail.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: H. Peter Anvin (Intel) <hpa@zytor.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200508105817.207887-1-ubizjak@gmail.com
diff --git a/arch/x86/include/asm/archrandom.h b/arch/x86/include/asm/archrandom.h
index 7a4bb1b..ebc248e4 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 @@
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 @@
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 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;
}
