[deliverable/linux.git] / arch / x86 / include / asm / archrandom.h

/*
 * This file is part of the Linux kernel.
 *
 * Copyright (c) 2011-2014, Intel Corporation
 * Authors: Fenghua Yu <fenghua.yu@intel.com>,
 *          H. Peter Anvin <hpa@linux.intel.com>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
 *
 */

#ifndef ASM_X86_ARCHRANDOM_H
#define ASM_X86_ARCHRANDOM_H

#include <asm/processor.h>
#include <asm/cpufeature.h>
#include <asm/alternative.h>
#include <asm/nops.h>

#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

#ifdef CONFIG_ARCH_RANDOM

/* Instead of arch_get_random_long() when alternatives haven't run. */
static inline int rdrand_long(unsigned long *v)
{
	int ok;
	asm volatile("1: " RDRAND_LONG "\n\t"
		     "jc 2f\n\t"
		     "decl %0\n\t"
		     "jnz 1b\n\t"
		     "2:"
		     : "=r" (ok), "=a" (*v)
		     : "0" (RDRAND_RETRY_LOOPS));
	return ok;
}

/* A single attempt at RDSEED */
static inline bool rdseed_long(unsigned long *v)
{
	unsigned char ok;
	asm volatile(RDSEED_LONG "\n\t"
		     "setc %0"
		     : "=qm" (ok), "=a" (*v));
	return ok;
}

#define GET_RANDOM(name, type, rdrand, nop)			\
static inline int name(type *v)					\
{								\
	int ok;							\
	alternative_io("movl $0, %0\n\t"			\
		       nop,					\
		       "\n1: " rdrand "\n\t"			\
		       "jc 2f\n\t"				\
		       "decl %0\n\t"                            \
		       "jnz 1b\n\t"                             \
		       "2:",                                    \
		       X86_FEATURE_RDRAND,                      \
		       ASM_OUTPUT2("=r" (ok), "=a" (*v)),       \
		       "0" (RDRAND_RETRY_LOOPS));		\
	return ok;						\
}

#define GET_SEED(name, type, rdseed, nop)			\
static inline int name(type *v)					\
{								\
	unsigned char ok;					\
	alternative_io("movb $0, %0\n\t"			\
		       nop,					\
		       rdseed "\n\t"				\
		       "setc %0",				\
		       X86_FEATURE_RDSEED,                      \
		       ASM_OUTPUT2("=q" (ok), "=a" (*v)));	\
	return ok;						\
}

#ifdef CONFIG_X86_64

GET_RANDOM(arch_get_random_long, unsigned long, RDRAND_LONG, ASM_NOP5);
GET_RANDOM(arch_get_random_int, unsigned int, RDRAND_INT, ASM_NOP4);

GET_SEED(arch_get_random_seed_long, unsigned long, RDSEED_LONG, ASM_NOP5);
GET_SEED(arch_get_random_seed_int, unsigned int, RDSEED_INT, ASM_NOP4);

#else

GET_RANDOM(arch_get_random_long, unsigned long, RDRAND_LONG, ASM_NOP3);
GET_RANDOM(arch_get_random_int, unsigned int, RDRAND_INT, ASM_NOP3);

GET_SEED(arch_get_random_seed_long, unsigned long, RDSEED_LONG, ASM_NOP4);
GET_SEED(arch_get_random_seed_int, unsigned int, RDSEED_INT, ASM_NOP4);

#endif /* CONFIG_X86_64 */

#define arch_has_random()	static_cpu_has(X86_FEATURE_RDRAND)
#define arch_has_random_seed()	static_cpu_has(X86_FEATURE_RDSEED)

#else

static inline int rdrand_long(unsigned long *v)
{
	return 0;
}

static inline bool rdseed_long(unsigned long *v)
{
	return 0;
}

#endif  /* CONFIG_ARCH_RANDOM */

extern void x86_init_rdrand(struct cpuinfo_x86 *c);

#endif /* ASM_X86_ARCHRANDOM_H */
Commit	Line	Data
628c6246 PA	1	/*
	2	* This file is part of the Linux kernel.
	3	*
d20f78d2	4	* Copyright (c) 2011-2014, Intel Corporation
628c6246 PA	5	* Authors: Fenghua Yu <fenghua.yu@intel.com>,
	6	* H. Peter Anvin <hpa@linux.intel.com>
	7	*
	8	* This program is free software; you can redistribute it and/or modify it
	9	* under the terms and conditions of the GNU General Public License,
	10	* version 2, as published by the Free Software Foundation.
	11	*
	12	* This program is distributed in the hope it will be useful, but WITHOUT
	13	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	14	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
	15	* more details.
	16	*
	17	* You should have received a copy of the GNU General Public License along with
	18	* this program; if not, write to the Free Software Foundation, Inc.,
	19	* 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
	20	*
	21	*/
	22
	23	#ifndef ASM_X86_ARCHRANDOM_H
	24	#define ASM_X86_ARCHRANDOM_H
	25
	26	#include <asm/processor.h>
	27	#include <asm/cpufeature.h>
	28	#include <asm/alternative.h>
	29	#include <asm/nops.h>
	30
	31	#define RDRAND_RETRY_LOOPS 10
	32
	33	#define RDRAND_INT ".byte 0x0f,0xc7,0xf0"
d20f78d2	34	#define RDSEED_INT ".byte 0x0f,0xc7,0xf8"
628c6246 PA	35	#ifdef CONFIG_X86_64
628c6246 PA	36	# define RDRAND_LONG ".byte 0x48,0x0f,0xc7,0xf0"
d20f78d2	37	# define RDSEED_LONG ".byte 0x48,0x0f,0xc7,0xf8"
628c6246 PA	38	#else
628c6246 PA	39	# define RDRAND_LONG RDRAND_INT
d20f78d2	40	# define RDSEED_LONG RDSEED_INT
628c6246 PA	41	#endif
	42
	43	#ifdef CONFIG_ARCH_RANDOM
	44
5bfce5ef KC	45	/* Instead of arch_get_random_long() when alternatives haven't run. */
	46	static inline int rdrand_long(unsigned long *v)
	47	{
	48	int ok;
	49	asm volatile("1: " RDRAND_LONG "\n\t"
	50	"jc 2f\n\t"
	51	"decl %0\n\t"
	52	"jnz 1b\n\t"
	53	"2:"
	54	: "=r" (ok), "=a" (*v)
	55	: "0" (RDRAND_RETRY_LOOPS));
	56	return ok;
	57	}
	58
d20f78d2 PA	59	/* A single attempt at RDSEED */
	60	static inline bool rdseed_long(unsigned long *v)
	61	{
	62	unsigned char ok;
	63	asm volatile(RDSEED_LONG "\n\t"
	64	"setc %0"
	65	: "=qm" (ok), "=a" (*v));
	66	return ok;
	67	}
	68
628c6246 PA	69	#define GET_RANDOM(name, type, rdrand, nop) \
	70	static inline int name(type *v) \
	71	{ \
	72	int ok; \
	73	alternative_io("movl $0, %0\n\t" \
	74	nop, \
	75	"\n1: " rdrand "\n\t" \
	76	"jc 2f\n\t" \
	77	"decl %0\n\t" \
	78	"jnz 1b\n\t" \
	79	"2:", \
	80	X86_FEATURE_RDRAND, \
	81	ASM_OUTPUT2("=r" (ok), "=a" (*v)), \
	82	"0" (RDRAND_RETRY_LOOPS)); \
	83	return ok; \
	84	}
	85
d20f78d2 PA	86	#define GET_SEED(name, type, rdseed, nop) \
	87	static inline int name(type *v) \
	88	{ \
	89	unsigned char ok; \
	90	alternative_io("movb $0, %0\n\t" \
	91	nop, \
	92	rdseed "\n\t" \
	93	"setc %0", \
	94	X86_FEATURE_RDSEED, \
	95	ASM_OUTPUT2("=q" (ok), "=a" (*v))); \
	96	return ok; \
	97	}
	98
628c6246 PA	99	#ifdef CONFIG_X86_64
	100
	101	GET_RANDOM(arch_get_random_long, unsigned long, RDRAND_LONG, ASM_NOP5);
	102	GET_RANDOM(arch_get_random_int, unsigned int, RDRAND_INT, ASM_NOP4);
	103
d20f78d2 PA	104	GET_SEED(arch_get_random_seed_long, unsigned long, RDSEED_LONG, ASM_NOP5);
	105	GET_SEED(arch_get_random_seed_int, unsigned int, RDSEED_INT, ASM_NOP4);
	106
628c6246 PA	107	#else
	108
	109	GET_RANDOM(arch_get_random_long, unsigned long, RDRAND_LONG, ASM_NOP3);
	110	GET_RANDOM(arch_get_random_int, unsigned int, RDRAND_INT, ASM_NOP3);
	111
d20f78d2 PA	112	GET_SEED(arch_get_random_seed_long, unsigned long, RDSEED_LONG, ASM_NOP4);
	113	GET_SEED(arch_get_random_seed_int, unsigned int, RDSEED_INT, ASM_NOP4);
	114
628c6246 PA	115	#endif /* CONFIG_X86_64 */
628c6246 PA	116
7b878d4b PA	117	#define arch_has_random() static_cpu_has(X86_FEATURE_RDRAND)
	118	#define arch_has_random_seed() static_cpu_has(X86_FEATURE_RDSEED)
	119
5bfce5ef KC	120	#else
	121
	122	static inline int rdrand_long(unsigned long *v)
	123	{
	124	return 0;
	125	}
	126
d20f78d2 PA	127	static inline bool rdseed_long(unsigned long *v)
	128	{
	129	return 0;
	130	}
	131
628c6246 PA	132	#endif /* CONFIG_ARCH_RANDOM */
628c6246 PA	133
49d859d7 PA	134	extern void x86_init_rdrand(struct cpuinfo_x86 *c);
49d859d7 PA	135
628c6246	136	#endif /* ASM_X86_ARCHRANDOM_H */