Differential D20192 Diff 57160 head/sys/dev/random/ivy.c

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head/sys/dev/random/ivy.c

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	#include <sys/lock.h>			#include <sys/lock.h>
	#include <sys/malloc.h>			#include <sys/malloc.h>
	#include <sys/module.h>			#include <sys/module.h>
	#include <sys/random.h>			#include <sys/random.h>
	#include <sys/systm.h>			#include <sys/systm.h>

	#include <machine/md_var.h>			#include <machine/md_var.h>
	#include <machine/specialreg.h>			#include <machine/specialreg.h>
				#include <x86/ifunc.h>

	#include <dev/random/randomdev.h>			#include <dev/random/randomdev.h>

	#define RETRY_COUNT 10			#define RETRY_COUNT 10

				static bool has_rdrand, has_rdseed;
	static u_int random_ivy_read(void *, u_int);			static u_int random_ivy_read(void *, u_int);

	static struct random_source random_ivy = {			static struct random_source random_ivy = {
	.rs_ident = "Intel Secure Key RNG",			.rs_ident = "Intel Secure Key RNG",
	.rs_source = RANDOM_PURE_RDRAND,			.rs_source = RANDOM_PURE_RDRAND,
	.rs_read = random_ivy_read			.rs_read = random_ivy_read
	};			};

	static inline int			static int
	ivy_rng_store(u_long *buf)			x86_rdrand_store(u_long *buf)
	{			{
	#ifdef __GNUCLIKE_ASM
	u_long rndval;			u_long rndval;
	int retry;			int retry;

	retry = RETRY_COUNT;			retry = RETRY_COUNT;
	__asm __volatile(			__asm __volatile(
	"1:\n\t"			"1:\n\t"
	"rdrand %1\n\t" /* read randomness into rndval */			"rdrand %1\n\t" /* read randomness into rndval */
	"jc 2f\n\t" /* CF is set on success, exit retry loop */			"jc 2f\n\t" /* CF is set on success, exit retry loop */
	"dec %0\n\t" /* otherwise, retry-- */			"dec %0\n\t" /* otherwise, retry-- */
	"jne 1b\n\t" /* and loop if retries are not exhausted */			"jne 1b\n\t" /* and loop if retries are not exhausted */
	"2:"			"2:"
	: "+r" (retry), "=r" (rndval) : : "cc");			: "+r" (retry), "=r" (rndval) : : "cc");
	*buf = rndval;			*buf = rndval;
	return (retry);			return (retry);
	#else /* __GNUCLIKE_ASM */
	return (0);
	#endif
	}			}

				static int
				x86_rdseed_store(u_long *buf)
				{
				u_long rndval;
				int retry;

				retry = RETRY_COUNT;
				__asm __volatile(
				"1:\n\t"
				"rdseed %1\n\t" /* read randomness into rndval */
				"jc 2f\n\t" /* CF is set on success, exit retry loop */
				"dec %0\n\t" /* otherwise, retry-- */
				"jne 1b\n\t" /* and loop if retries are not exhausted */
				"2:"
				: "+r" (retry), "=r" (rndval) : : "cc");
				*buf = rndval;
				return (retry);
				}

				DEFINE_IFUNC(static, int, x86_rng_store, (u_long *buf), static)
				{
				has_rdrand = (cpu_feature2 & CPUID2_RDRAND);
				has_rdseed = (cpu_stdext_feature & CPUID_STDEXT_RDSEED);

				if (has_rdseed)
				return (x86_rdseed_store);
				else if (has_rdrand)
				return (x86_rdrand_store);
				else
				return (NULL);
				}

	/* It is required that buf length is a multiple of sizeof(u_long). */			/* It is required that buf length is a multiple of sizeof(u_long). */
	static u_int			static u_int
	random_ivy_read(void *buf, u_int c)			random_ivy_read(void *buf, u_int c)
	{			{
	u_long *b, rndval;			u_long *b, rndval;
	u_int count;			u_int count;

	KASSERT(c % sizeof(*b) == 0, ("partial read %d", c));			KASSERT(c % sizeof(*b) == 0, ("partial read %d", c));
	b = buf;			b = buf;
	for (count = c; count > 0; count -= sizeof(*b)) {			for (count = c; count > 0; count -= sizeof(*b)) {
	if (ivy_rng_store(&rndval) == 0)			if (x86_rng_store(&rndval) == 0)
	break;			break;
	*b++ = rndval;			*b++ = rndval;
	}			}
	return (c - count);			return (c - count);
	}			}

	static int			static int
	rdrand_modevent(module_t mod, int type, void *unused)			rdrand_modevent(module_t mod, int type, void *unused)
	{			{
	int error = 0;			int error = 0;

	switch (type) {			switch (type) {
	case MOD_LOAD:			case MOD_LOAD:
	if (cpu_feature2 & CPUID2_RDRAND) {			if (has_rdrand \|\| has_rdseed) {
	random_source_register(&random_ivy);			random_source_register(&random_ivy);
	printf("random: fast provider: \"%s\"\n", random_ivy.rs_ident);			printf("random: fast provider: \"%s\"\n", random_ivy.rs_ident);
	}			}
	break;			break;

	case MOD_UNLOAD:			case MOD_UNLOAD:
	if (cpu_feature2 & CPUID2_RDRAND)			if (has_rdrand \|\| has_rdseed)
	random_source_deregister(&random_ivy);			random_source_deregister(&random_ivy);
	break;			break;

	case MOD_SHUTDOWN:			case MOD_SHUTDOWN:
	break;			break;

	default:			default:
	error = EOPNOTSUPP;			error = EOPNOTSUPP;
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