[linux.git] / lib / random32.c

// SPDX-License-Identifier: GPL-2.0
/*
 * This is a maximally equidistributed combined Tausworthe generator
 * based on code from GNU Scientific Library 1.5 (30 Jun 2004)
 *
 * lfsr113 version:
 *
 * x_n = (s1_n ^ s2_n ^ s3_n ^ s4_n)
 *
 * s1_{n+1} = (((s1_n & 4294967294) << 18) ^ (((s1_n <<  6) ^ s1_n) >> 13))
 * s2_{n+1} = (((s2_n & 4294967288) <<  2) ^ (((s2_n <<  2) ^ s2_n) >> 27))
 * s3_{n+1} = (((s3_n & 4294967280) <<  7) ^ (((s3_n << 13) ^ s3_n) >> 21))
 * s4_{n+1} = (((s4_n & 4294967168) << 13) ^ (((s4_n <<  3) ^ s4_n) >> 12))
 *
 * The period of this generator is about 2^113 (see erratum paper).
 *
 * From: P. L'Ecuyer, "Maximally Equidistributed Combined Tausworthe
 * Generators", Mathematics of Computation, 65, 213 (1996), 203--213:
 * http://www.iro.umontreal.ca/~lecuyer/myftp/papers/tausme.ps
 * ftp://ftp.iro.umontreal.ca/pub/simulation/lecuyer/papers/tausme.ps
 *
 * There is an erratum in the paper "Tables of Maximally Equidistributed
 * Combined LFSR Generators", Mathematics of Computation, 68, 225 (1999),
 * 261--269: http://www.iro.umontreal.ca/~lecuyer/myftp/papers/tausme2.ps
 *
 *      ... the k_j most significant bits of z_j must be non-zero,
 *      for each j. (Note: this restriction also applies to the
 *      computer code given in [4], but was mistakenly not mentioned
 *      in that paper.)
 *
 * This affects the seeding procedure by imposing the requirement
 * s1 > 1, s2 > 7, s3 > 15, s4 > 127.
 */

#include <linux/types.h>
#include <linux/percpu.h>
#include <linux/export.h>
#include <linux/jiffies.h>
#include <linux/random.h>
#include <linux/sched.h>
#include <linux/bitops.h>
#include <linux/slab.h>
#include <asm/unaligned.h>

/**
 *	prandom_u32_state - seeded pseudo-random number generator.
 *	@state: pointer to state structure holding seeded state.
 *
 *	This is used for pseudo-randomness with no outside seeding.
 *	For more random results, use get_random_u32().
 */
u32 prandom_u32_state(struct rnd_state *state)
{
#define TAUSWORTHE(s, a, b, c, d) ((s & c) << d) ^ (((s << a) ^ s) >> b)
	state->s1 = TAUSWORTHE(state->s1,  6U, 13U, 4294967294U, 18U);
	state->s2 = TAUSWORTHE(state->s2,  2U, 27U, 4294967288U,  2U);
	state->s3 = TAUSWORTHE(state->s3, 13U, 21U, 4294967280U,  7U);
	state->s4 = TAUSWORTHE(state->s4,  3U, 12U, 4294967168U, 13U);

	return (state->s1 ^ state->s2 ^ state->s3 ^ state->s4);
}
EXPORT_SYMBOL(prandom_u32_state);

/**
 *	prandom_bytes_state - get the requested number of pseudo-random bytes
 *
 *	@state: pointer to state structure holding seeded state.
 *	@buf: where to copy the pseudo-random bytes to
 *	@bytes: the requested number of bytes
 *
 *	This is used for pseudo-randomness with no outside seeding.
 *	For more random results, use prandom_bytes().
 */
void prandom_bytes_state(struct rnd_state *state, void *buf, size_t bytes)
{
	u8 *ptr = buf;

	while (bytes >= sizeof(u32)) {
		put_unaligned(prandom_u32_state(state), (u32 *) ptr);
		ptr += sizeof(u32);
		bytes -= sizeof(u32);
	}

	if (bytes > 0) {
		u32 rem = prandom_u32_state(state);
		do {
			*ptr++ = (u8) rem;
			bytes--;
			rem >>= BITS_PER_BYTE;
		} while (bytes > 0);
	}
}
EXPORT_SYMBOL(prandom_bytes_state);

static void prandom_warmup(struct rnd_state *state)
{
	/* Calling RNG ten times to satisfy recurrence condition */
	prandom_u32_state(state);
	prandom_u32_state(state);
	prandom_u32_state(state);
	prandom_u32_state(state);
	prandom_u32_state(state);
	prandom_u32_state(state);
	prandom_u32_state(state);
	prandom_u32_state(state);
	prandom_u32_state(state);
	prandom_u32_state(state);
}

void prandom_seed_full_state(struct rnd_state __percpu *pcpu_state)
{
	int i;

	for_each_possible_cpu(i) {
		struct rnd_state *state = per_cpu_ptr(pcpu_state, i);
		u32 seeds[4];

		get_random_bytes(&seeds, sizeof(seeds));
		state->s1 = __seed(seeds[0],   2U);
		state->s2 = __seed(seeds[1],   8U);
		state->s3 = __seed(seeds[2],  16U);
		state->s4 = __seed(seeds[3], 128U);

		prandom_warmup(state);
	}
}
EXPORT_SYMBOL(prandom_seed_full_state);

#ifdef CONFIG_RANDOM32_SELFTEST
static struct prandom_test1 {
	u32 seed;
	u32 result;
} test1[] = {
	{ 1U, 3484351685U },
	{ 2U, 2623130059U },
	{ 3U, 3125133893U },
	{ 4U,  984847254U },
};

static struct prandom_test2 {
	u32 seed;
	u32 iteration;
	u32 result;
} test2[] = {
	/* Test cases against taus113 from GSL library. */
	{  931557656U, 959U, 2975593782U },
	{ 1339693295U, 876U, 3887776532U },
	{ 1545556285U, 961U, 1615538833U },
	{  601730776U, 723U, 1776162651U },
	{ 1027516047U, 687U,  511983079U },
	{  416526298U, 700U,  916156552U },
	{ 1395522032U, 652U, 2222063676U },
	{  366221443U, 617U, 2992857763U },
	{ 1539836965U, 714U, 3783265725U },
	{  556206671U, 994U,  799626459U },
	{  684907218U, 799U,  367789491U },
	{ 2121230701U, 931U, 2115467001U },
	{ 1668516451U, 644U, 3620590685U },
	{  768046066U, 883U, 2034077390U },
	{ 1989159136U, 833U, 1195767305U },
	{  536585145U, 996U, 3577259204U },
	{ 1008129373U, 642U, 1478080776U },
	{ 1740775604U, 939U, 1264980372U },
	{ 1967883163U, 508U,   10734624U },
	{ 1923019697U, 730U, 3821419629U },
	{  442079932U, 560U, 3440032343U },
	{ 1961302714U, 845U,  841962572U },
	{ 2030205964U, 962U, 1325144227U },
	{ 1160407529U, 507U,  240940858U },
	{  635482502U, 779U, 4200489746U },
	{ 1252788931U, 699U,  867195434U },
	{ 1961817131U, 719U,  668237657U },
	{ 1071468216U, 983U,  917876630U },
	{ 1281848367U, 932U, 1003100039U },
	{  582537119U, 780U, 1127273778U },
	{ 1973672777U, 853U, 1071368872U },
	{ 1896756996U, 762U, 1127851055U },
	{  847917054U, 500U, 1717499075U },
	{ 1240520510U, 951U, 2849576657U },
	{ 1685071682U, 567U, 1961810396U },
	{ 1516232129U, 557U,    3173877U },
	{ 1208118903U, 612U, 1613145022U },
	{ 1817269927U, 693U, 4279122573U },
	{ 1510091701U, 717U,  638191229U },
	{  365916850U, 807U,  600424314U },
	{  399324359U, 702U, 1803598116U },
	{ 1318480274U, 779U, 2074237022U },
	{  697758115U, 840U, 1483639402U },
	{ 1696507773U, 840U,  577415447U },
	{ 2081979121U, 981U, 3041486449U },
	{  955646687U, 742U, 3846494357U },
	{ 1250683506U, 749U,  836419859U },
	{  595003102U, 534U,  366794109U },
	{   47485338U, 558U, 3521120834U },
	{  619433479U, 610U, 3991783875U },
	{  704096520U, 518U, 4139493852U },
	{ 1712224984U, 606U, 2393312003U },
	{ 1318233152U, 922U, 3880361134U },
	{  855572992U, 761U, 1472974787U },
	{   64721421U, 703U,  683860550U },
	{  678931758U, 840U,  380616043U },
	{  692711973U, 778U, 1382361947U },
	{  677703619U, 530U, 2826914161U },
	{   92393223U, 586U, 1522128471U },
	{ 1222592920U, 743U, 3466726667U },
	{  358288986U, 695U, 1091956998U },
	{ 1935056945U, 958U,  514864477U },
	{  735675993U, 990U, 1294239989U },
	{ 1560089402U, 897U, 2238551287U },
	{   70616361U, 829U,   22483098U },
	{  368234700U, 731U, 2913875084U },
	{   20221190U, 879U, 1564152970U },
	{  539444654U, 682U, 1835141259U },
	{ 1314987297U, 840U, 1801114136U },
	{ 2019295544U, 645U, 3286438930U },
	{  469023838U, 716U, 1637918202U },
	{ 1843754496U, 653U, 2562092152U },
	{  400672036U, 809U, 4264212785U },
	{  404722249U, 965U, 2704116999U },
	{  600702209U, 758U,  584979986U },
	{  519953954U, 667U, 2574436237U },
	{ 1658071126U, 694U, 2214569490U },
	{  420480037U, 749U, 3430010866U },
	{  690103647U, 969U, 3700758083U },
	{ 1029424799U, 937U, 3787746841U },
	{ 2012608669U, 506U, 3362628973U },
	{ 1535432887U, 998U,   42610943U },
	{ 1330635533U, 857U, 3040806504U },
	{ 1223800550U, 539U, 3954229517U },
	{ 1322411537U, 680U, 3223250324U },
	{ 1877847898U, 945U, 2915147143U },
	{ 1646356099U, 874U,  965988280U },
	{  805687536U, 744U, 4032277920U },
	{ 1948093210U, 633U, 1346597684U },
	{  392609744U, 783U, 1636083295U },
	{  690241304U, 770U, 1201031298U },
	{ 1360302965U, 696U, 1665394461U },
	{ 1220090946U, 780U, 1316922812U },
	{  447092251U, 500U, 3438743375U },
	{ 1613868791U, 592U,  828546883U },
	{  523430951U, 548U, 2552392304U },
	{  726692899U, 810U, 1656872867U },
	{ 1364340021U, 836U, 3710513486U },
	{ 1986257729U, 931U,  935013962U },
	{  407983964U, 921U,  728767059U },
};

static void prandom_state_selftest_seed(struct rnd_state *state, u32 seed)
{
#define LCG(x)	 ((x) * 69069U)	/* super-duper LCG */
	state->s1 = __seed(LCG(seed),        2U);
	state->s2 = __seed(LCG(state->s1),   8U);
	state->s3 = __seed(LCG(state->s2),  16U);
	state->s4 = __seed(LCG(state->s3), 128U);
}

static int __init prandom_state_selftest(void)
{
	int i, j, errors = 0, runs = 0;
	bool error = false;

	for (i = 0; i < ARRAY_SIZE(test1); i++) {
		struct rnd_state state;

		prandom_state_selftest_seed(&state, test1[i].seed);
		prandom_warmup(&state);

		if (test1[i].result != prandom_u32_state(&state))
			error = true;
	}

	if (error)
		pr_warn("prandom: seed boundary self test failed\n");
	else
		pr_info("prandom: seed boundary self test passed\n");

	for (i = 0; i < ARRAY_SIZE(test2); i++) {
		struct rnd_state state;

		prandom_state_selftest_seed(&state, test2[i].seed);
		prandom_warmup(&state);

		for (j = 0; j < test2[i].iteration - 1; j++)
			prandom_u32_state(&state);

		if (test2[i].result != prandom_u32_state(&state))
			errors++;

		runs++;
		cond_resched();
	}

	if (errors)
		pr_warn("prandom: %d/%d self tests failed\n", errors, runs);
	else
		pr_info("prandom: %d self tests passed\n", runs);
	return 0;
}
core_initcall(prandom_state_selftest);
#endif
Commit	Line	Data
b2441318	1	// SPDX-License-Identifier: GPL-2.0
aaa248f6	2	/*
d3d47eb2 DB	3	* This is a maximally equidistributed combined Tausworthe generator
	4	* based on code from GNU Scientific Library 1.5 (30 Jun 2004)
	5	*
	6	* lfsr113 version:
	7	*
	8	* x_n = (s1_n ^ s2_n ^ s3_n ^ s4_n)
	9	*
	10	* s1_{n+1} = (((s1_n & 4294967294) << 18) ^ (((s1_n << 6) ^ s1_n) >> 13))
	11	* s2_{n+1} = (((s2_n & 4294967288) << 2) ^ (((s2_n << 2) ^ s2_n) >> 27))
	12	* s3_{n+1} = (((s3_n & 4294967280) << 7) ^ (((s3_n << 13) ^ s3_n) >> 21))
	13	* s4_{n+1} = (((s4_n & 4294967168) << 13) ^ (((s4_n << 3) ^ s4_n) >> 12))
	14	*
	15	* The period of this generator is about 2^113 (see erratum paper).
	16	*
	17	* From: P. L'Ecuyer, "Maximally Equidistributed Combined Tausworthe
	18	* Generators", Mathematics of Computation, 65, 213 (1996), 203--213:
	19	* http://www.iro.umontreal.ca/~lecuyer/myftp/papers/tausme.ps
	20	* ftp://ftp.iro.umontreal.ca/pub/simulation/lecuyer/papers/tausme.ps
	21	*
	22	* There is an erratum in the paper "Tables of Maximally Equidistributed
	23	* Combined LFSR Generators", Mathematics of Computation, 68, 225 (1999),
	24	* 261--269: http://www.iro.umontreal.ca/~lecuyer/myftp/papers/tausme2.ps
	25	*
	26	* ... the k_j most significant bits of z_j must be non-zero,
	27	* for each j. (Note: this restriction also applies to the
	28	* computer code given in [4], but was mistakenly not mentioned
	29	* in that paper.)
	30	*
	31	* This affects the seeding procedure by imposing the requirement
	32	* s1 > 1, s2 > 7, s3 > 15, s4 > 127.
	33	*/
aaa248f6 SH	34
	35	#include <linux/types.h>
	36	#include <linux/percpu.h>
8bc3bcc9	37	#include <linux/export.h>
f6a57033	38	#include <linux/jiffies.h>
aaa248f6	39	#include <linux/random.h>
a6a9c0f1	40	#include <linux/sched.h>
c6e169bc	41	#include <linux/bitops.h>
348332e0	42	#include <linux/slab.h>
a98406e2	43	#include <asm/unaligned.h>
a6a9c0f1	44
5960164f	45	/**
496f2f93	46	* prandom_u32_state - seeded pseudo-random number generator.
5960164f JE	47	* @state: pointer to state structure holding seeded state.
	48	*
	49	* This is used for pseudo-randomness with no outside seeding.
a251c17a	50	* For more random results, use get_random_u32().
5960164f	51	*/
496f2f93	52	u32 prandom_u32_state(struct rnd_state *state)
aaa248f6	53	{
4ada97ab	54	#define TAUSWORTHE(s, a, b, c, d) ((s & c) << d) ^ (((s << a) ^ s) >> b)
a98814ce DB	55	state->s1 = TAUSWORTHE(state->s1, 6U, 13U, 4294967294U, 18U);
	56	state->s2 = TAUSWORTHE(state->s2, 2U, 27U, 4294967288U, 2U);
	57	state->s3 = TAUSWORTHE(state->s3, 13U, 21U, 4294967280U, 7U);
	58	state->s4 = TAUSWORTHE(state->s4, 3U, 12U, 4294967168U, 13U);
aaa248f6	59
a98814ce	60	return (state->s1 ^ state->s2 ^ state->s3 ^ state->s4);
aaa248f6	61	}
496f2f93	62	EXPORT_SYMBOL(prandom_u32_state);
aaa248f6	63
d3d47eb2	64	/**
6582c665 AM	65	* prandom_bytes_state - get the requested number of pseudo-random bytes
	66	*
	67	* @state: pointer to state structure holding seeded state.
	68	* @buf: where to copy the pseudo-random bytes to
	69	* @bytes: the requested number of bytes
	70	*
	71	* This is used for pseudo-randomness with no outside seeding.
	72	* For more random results, use prandom_bytes().
	73	*/
a98406e2	74	void prandom_bytes_state(struct rnd_state state, void buf, size_t bytes)
6582c665	75	{
a98406e2	76	u8 *ptr = buf;
6582c665	77
a98406e2 DB	78	while (bytes >= sizeof(u32)) {
	79	put_unaligned(prandom_u32_state(state), (u32 *) ptr);
	80	ptr += sizeof(u32);
	81	bytes -= sizeof(u32);
6582c665	82	}
6582c665	83
a98406e2 DB	84	if (bytes > 0) {
	85	u32 rem = prandom_u32_state(state);
	86	do {
	87	*ptr++ = (u8) rem;
	88	bytes--;
	89	rem >>= BITS_PER_BYTE;
	90	} while (bytes > 0);
6582c665 AM	91	}
	92	}
	93	EXPORT_SYMBOL(prandom_bytes_state);
	94
a98814ce DB	95	static void prandom_warmup(struct rnd_state *state)
a98814ce DB	96	{
a98406e2	97	/* Calling RNG ten times to satisfy recurrence condition */
a98814ce DB	98	prandom_u32_state(state);
	99	prandom_u32_state(state);
	100	prandom_u32_state(state);
	101	prandom_u32_state(state);
	102	prandom_u32_state(state);
	103	prandom_u32_state(state);
	104	prandom_u32_state(state);
	105	prandom_u32_state(state);
	106	prandom_u32_state(state);
	107	prandom_u32_state(state);
	108	}
	109
897ece56	110	void prandom_seed_full_state(struct rnd_state __percpu *pcpu_state)
0dd50d1b DB	111	{
	112	int i;
	113
	114	for_each_possible_cpu(i) {
	115	struct rnd_state *state = per_cpu_ptr(pcpu_state, i);
	116	u32 seeds[4];
	117
	118	get_random_bytes(&seeds, sizeof(seeds));
	119	state->s1 = __seed(seeds[0], 2U);
	120	state->s2 = __seed(seeds[1], 8U);
	121	state->s3 = __seed(seeds[2], 16U);
	122	state->s4 = __seed(seeds[3], 128U);
	123
	124	prandom_warmup(state);
	125	}
	126	}
b07edbe1	127	EXPORT_SYMBOL(prandom_seed_full_state);
0dd50d1b	128
a6a9c0f1 DB	129	#ifdef CONFIG_RANDOM32_SELFTEST
	130	static struct prandom_test1 {
	131	u32 seed;
	132	u32 result;
	133	} test1[] = {
	134	{ 1U, 3484351685U },
	135	{ 2U, 2623130059U },
	136	{ 3U, 3125133893U },
	137	{ 4U, 984847254U },
	138	};
	139
	140	static struct prandom_test2 {
	141	u32 seed;
	142	u32 iteration;
	143	u32 result;
	144	} test2[] = {
	145	/* Test cases against taus113 from GSL library. */
	146	{ 931557656U, 959U, 2975593782U },
	147	{ 1339693295U, 876U, 3887776532U },
	148	{ 1545556285U, 961U, 1615538833U },
	149	{ 601730776U, 723U, 1776162651U },
	150	{ 1027516047U, 687U, 511983079U },
	151	{ 416526298U, 700U, 916156552U },
	152	{ 1395522032U, 652U, 2222063676U },
	153	{ 366221443U, 617U, 2992857763U },
	154	{ 1539836965U, 714U, 3783265725U },
	155	{ 556206671U, 994U, 799626459U },
	156	{ 684907218U, 799U, 367789491U },
	157	{ 2121230701U, 931U, 2115467001U },
	158	{ 1668516451U, 644U, 3620590685U },
	159	{ 768046066U, 883U, 2034077390U },
	160	{ 1989159136U, 833U, 1195767305U },
	161	{ 536585145U, 996U, 3577259204U },
	162	{ 1008129373U, 642U, 1478080776U },
	163	{ 1740775604U, 939U, 1264980372U },
	164	{ 1967883163U, 508U, 10734624U },
	165	{ 1923019697U, 730U, 3821419629U },
	166	{ 442079932U, 560U, 3440032343U },
	167	{ 1961302714U, 845U, 841962572U },
	168	{ 2030205964U, 962U, 1325144227U },
	169	{ 1160407529U, 507U, 240940858U },
	170	{ 635482502U, 779U, 4200489746U },
	171	{ 1252788931U, 699U, 867195434U },
	172	{ 1961817131U, 719U, 668237657U },
	173	{ 1071468216U, 983U, 917876630U },
	174	{ 1281848367U, 932U, 1003100039U },
	175	{ 582537119U, 780U, 1127273778U },
	176	{ 1973672777U, 853U, 1071368872U },
	177	{ 1896756996U, 762U, 1127851055U },
	178	{ 847917054U, 500U, 1717499075U },
	179	{ 1240520510U, 951U, 2849576657U },
	180	{ 1685071682U, 567U, 1961810396U },
	181	{ 1516232129U, 557U, 3173877U },
	182	{ 1208118903U, 612U, 1613145022U },
	183	{ 1817269927U, 693U, 4279122573U },
	184	{ 1510091701U, 717U, 638191229U },
	185	{ 365916850U, 807U, 600424314U },
	186	{ 399324359U, 702U, 1803598116U },
	187	{ 1318480274U, 779U, 2074237022U },
	188	{ 697758115U, 840U, 1483639402U },
	189	{ 1696507773U, 840U, 577415447U },
	190	{ 2081979121U, 981U, 3041486449U },
	191	{ 955646687U, 742U, 3846494357U },
	192	{ 1250683506U, 749U, 836419859U },
193	{ 595003102U, 534U, 366794109U },
194	{ 47485338U, 558U, 3521120834U },
195	{ 619433479U, 610U, 3991783875U },
196	{ 704096520U, 518U, 4139493852U },
197	{ 1712224984U, 606U, 2393312003U },
198	{ 1318233152U, 922U, 3880361134U },
199	{ 855572992U, 761U, 1472974787U },
200	{ 64721421U, 703U, 683860550U },
201	{ 678931758U, 840U, 380616043U },
202	{ 692711973U, 778U, 1382361947U },
203	{ 677703619U, 530U, 2826914161U },
204	{ 92393223U, 586U, 1522128471U },
205	{ 1222592920U, 743U, 3466726667U },
206	{ 358288986U, 695U, 1091956998U },
207	{ 1935056945U, 958U, 514864477U },
208	{ 735675993U, 990U, 1294239989U },
209	{ 1560089402U, 897U, 2238551287U },
210	{ 70616361U, 829U, 22483098U },
211	{ 368234700U, 731U, 2913875084U },
212	{ 20221190U, 879U, 1564152970U },
213	{ 539444654U, 682U, 1835141259U },
214	{ 1314987297U, 840U, 1801114136U },
215	{ 2019295544U, 645U, 3286438930U },
216	{ 469023838U, 716U, 1637918202U },
217	{ 1843754496U, 653U, 2562092152U },
218	{ 400672036U, 809U, 4264212785U },
219	{ 404722249U, 965U, 2704116999U },
220	{ 600702209U, 758U, 584979986U },
221	{ 519953954U, 667U, 2574436237U },
222	{ 1658071126U, 694U, 2214569490U },
223	{ 420480037U, 749U, 3430010866U },
224	{ 690103647U, 969U, 3700758083U },
225	{ 1029424799U, 937U, 3787746841U },
226	{ 2012608669U, 506U, 3362628973U },
227	{ 1535432887U, 998U, 42610943U },
228	{ 1330635533U, 857U, 3040806504U },
229	{ 1223800550U, 539U, 3954229517U },
230	{ 1322411537U, 680U, 3223250324U },
231	{ 1877847898U, 945U, 2915147143U },
232	{ 1646356099U, 874U, 965988280U },
233	{ 805687536U, 744U, 4032277920U },
234	{ 1948093210U, 633U, 1346597684U },
235	{ 392609744U, 783U, 1636083295U },
236	{ 690241304U, 770U, 1201031298U },
237	{ 1360302965U, 696U, 1665394461U },
238	{ 1220090946U, 780U, 1316922812U },
239	{ 447092251U, 500U, 3438743375U },
240	{ 1613868791U, 592U, 828546883U },
241	{ 523430951U, 548U, 2552392304U },
242	{ 726692899U, 810U, 1656872867U },
243	{ 1364340021U, 836U, 3710513486U },
244	{ 1986257729U, 931U, 935013962U },
245	{ 407983964U, 921U, 728767059U },
246	};
247
d4150779	248	static void prandom_state_selftest_seed(struct rnd_state *state, u32 seed)
c51f8f88 GS	249	{
c51f8f88 GS	250	#define LCG(x) ((x) * 69069U) /* super-duper LCG */
d4150779 JD	251	state->s1 = __seed(LCG(seed), 2U);
	252	state->s2 = __seed(LCG(state->s1), 8U);
	253	state->s3 = __seed(LCG(state->s2), 16U);
	254	state->s4 = __seed(LCG(state->s3), 128U);
c51f8f88 GS	255	}
	256
	257	static int __init prandom_state_selftest(void)
a6a9c0f1 DB	258	{
	259	int i, j, errors = 0, runs = 0;
	260	bool error = false;
	261
	262	for (i = 0; i < ARRAY_SIZE(test1); i++) {
	263	struct rnd_state state;
	264
d4150779	265	prandom_state_selftest_seed(&state, test1[i].seed);
a6a9c0f1 DB	266	prandom_warmup(&state);
	267
	268	if (test1[i].result != prandom_u32_state(&state))
	269	error = true;
	270	}
	271
	272	if (error)
	273	pr_warn("prandom: seed boundary self test failed\n");
	274	else
	275	pr_info("prandom: seed boundary self test passed\n");
	276
	277	for (i = 0; i < ARRAY_SIZE(test2); i++) {
	278	struct rnd_state state;
	279
d4150779	280	prandom_state_selftest_seed(&state, test2[i].seed);
a6a9c0f1 DB	281	prandom_warmup(&state);
	282
	283	for (j = 0; j < test2[i].iteration - 1; j++)
	284	prandom_u32_state(&state);
	285
	286	if (test2[i].result != prandom_u32_state(&state))
	287	errors++;
	288
	289	runs++;
	290	cond_resched();
	291	}
	292
	293	if (errors)
	294	pr_warn("prandom: %d/%d self tests failed\n", errors, runs);
	295	else
	296	pr_info("prandom: %d self tests passed\n", runs);
c51f8f88	297	return 0;
a6a9c0f1	298	}
c51f8f88	299	core_initcall(prandom_state_selftest);
a6a9c0f1	300	#endif