Differential D22455 Diff 64735 head/sys/dev/random/ivy.c

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head/sys/dev/random/ivy.c

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	#include <sys/param.h>			#include <sys/param.h>
	#include <sys/kernel.h>			#include <sys/kernel.h>
	#include <sys/conf.h>			#include <sys/conf.h>
	#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/sysctl.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 <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 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
	};			};

				SYSCTL_NODE(_kern_random, OID_AUTO, rdrand, CTLFLAG_RW, 0,
				"rdrand (ivy) entropy source");
				static bool acquire_independent_seed_samples = false;
				SYSCTL_BOOL(_kern_random_rdrand, OID_AUTO, rdrand_independent_seed,
				CTLFLAG_RWTUN, &acquire_independent_seed_samples, 0,
				"If non-zero, use more expensive and slow, but safer, seeded samples "
				"where RDSEED is not present.");

	static bool			static bool
	x86_rdrand_store(u_long *buf)			x86_rdrand_store(u_long *buf)
	{			{
	u_long rndval;			u_long rndval, seed_iterations, i;
	int retry;			int retry;

				/* Per [1], "§ 5.2.6 Generating Seeds from RDRAND,"
				* machines lacking RDSEED will guarantee RDRAND is reseeded every 8kB
				* of generated output.
				*
				* [1]: https://software.intel.com/en-us/articles/intel-digital-random-number-generator-drng-software-implementation-guide#inpage-nav-6-8
				*/
				if (acquire_independent_seed_samples)
				seed_iterations = 8 * 1024 / sizeof(*buf);
				else
				seed_iterations = 1;

				for (i = 0; i < seed_iterations; i++) {
	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");
				if (retry == 0)
				return (false);
				}
	*buf = rndval;			*buf = rndval;
	return (retry != 0);			return (true);
	}			}

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

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