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author | Ingo Molnar <mingo@elte.hu> | 2008-08-20 12:39:18 +0200 |
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committer | Ingo Molnar <mingo@elte.hu> | 2008-08-20 12:39:18 +0200 |
commit | 170465ee7f5a9a2d0ac71285507e52642e040353 (patch) | |
tree | dbca81f04cde9e625170abbd6a72555cfbeb194e /lib/random32.c | |
parent | 169ad16bb87c10a3f7c108bb7008ebc0270f617a (diff) | |
parent | 1fca25427482387689fa27594c992a961d98768f (diff) | |
download | linux-170465ee7f5a9a2d0ac71285507e52642e040353.tar.gz linux-170465ee7f5a9a2d0ac71285507e52642e040353.tar.bz2 linux-170465ee7f5a9a2d0ac71285507e52642e040353.zip |
Merge branch 'linus' into x86/xen
Diffstat (limited to 'lib/random32.c')
-rw-r--r-- | lib/random32.c | 48 |
1 files changed, 27 insertions, 21 deletions
diff --git a/lib/random32.c b/lib/random32.c index ca87d86992bd..217d5c4b666d 100644 --- a/lib/random32.c +++ b/lib/random32.c @@ -56,23 +56,12 @@ static u32 __random32(struct rnd_state *state) return (state->s1 ^ state->s2 ^ state->s3); } -static void __set_random32(struct rnd_state *state, unsigned long s) +/* + * Handle minimum values for seeds + */ +static inline u32 __seed(u32 x, u32 m) { - if (s == 0) - s = 1; /* default seed is 1 */ - -#define LCG(n) (69069 * n) - state->s1 = LCG(s); - state->s2 = LCG(state->s1); - state->s3 = LCG(state->s2); - - /* "warm it up" */ - __random32(state); - __random32(state); - __random32(state); - __random32(state); - __random32(state); - __random32(state); + return (x < m) ? x + m : x; } /** @@ -107,7 +96,7 @@ void srandom32(u32 entropy) */ for_each_possible_cpu (i) { struct rnd_state *state = &per_cpu(net_rand_state, i); - __set_random32(state, state->s1 ^ entropy); + state->s1 = __seed(state->s1 ^ entropy, 1); } } EXPORT_SYMBOL(srandom32); @@ -122,7 +111,19 @@ static int __init random32_init(void) for_each_possible_cpu(i) { struct rnd_state *state = &per_cpu(net_rand_state,i); - __set_random32(state, i + jiffies); + +#define LCG(x) ((x) * 69069) /* super-duper LCG */ + state->s1 = __seed(LCG(i + jiffies), 1); + state->s2 = __seed(LCG(state->s1), 7); + state->s3 = __seed(LCG(state->s2), 15); + + /* "warm it up" */ + __random32(state); + __random32(state); + __random32(state); + __random32(state); + __random32(state); + __random32(state); } return 0; } @@ -135,13 +136,18 @@ core_initcall(random32_init); static int __init random32_reseed(void) { int i; - unsigned long seed; for_each_possible_cpu(i) { struct rnd_state *state = &per_cpu(net_rand_state,i); + u32 seeds[3]; + + get_random_bytes(&seeds, sizeof(seeds)); + state->s1 = __seed(seeds[0], 1); + state->s2 = __seed(seeds[1], 7); + state->s3 = __seed(seeds[2], 15); - get_random_bytes(&seed, sizeof(seed)); - __set_random32(state, seed); + /* mix it in */ + __random32(state); } return 0; } |