diff options
Diffstat (limited to 'drivers/char/random.c')
| -rw-r--r-- | drivers/char/random.c | 24 |
1 files changed, 20 insertions, 4 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c index d07575c99a5f..a4bea7775e0f 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -844,6 +844,8 @@ void add_interrupt_randomness(int irq, int irq_flags) cycles_t cycles = random_get_entropy(); __u32 input[4], c_high, j_high; __u64 ip; + unsigned long seed; + int credit; c_high = (sizeof(cycles) > 4) ? cycles >> 32 : 0; j_high = (sizeof(now) > 4) ? now >> 32 : 0; @@ -862,20 +864,33 @@ void add_interrupt_randomness(int irq, int irq_flags) r = nonblocking_pool.initialized ? &input_pool : &nonblocking_pool; __mix_pool_bytes(r, &fast_pool->pool, sizeof(fast_pool->pool), NULL); + /* * If we don't have a valid cycle counter, and we see * back-to-back timer interrupts, then skip giving credit for - * any entropy. + * any entropy, otherwise credit 1 bit. */ + credit = 1; if (cycles == 0) { if (irq_flags & __IRQF_TIMER) { if (fast_pool->last_timer_intr) - return; + credit = 0; fast_pool->last_timer_intr = 1; } else fast_pool->last_timer_intr = 0; } - credit_entropy_bits(r, 1); + + /* + * If we have architectural seed generator, produce a seed and + * add it to the pool. For the sake of paranoia count it as + * 50% entropic. + */ + if (arch_get_random_seed_long(&seed)) { + __mix_pool_bytes(r, &seed, sizeof(seed), NULL); + credit += sizeof(seed) * 4; + } + + credit_entropy_bits(r, credit); } #ifdef CONFIG_BLOCK @@ -1235,7 +1250,8 @@ static void init_std_data(struct entropy_store *r) r->last_pulled = jiffies; mix_pool_bytes(r, &now, sizeof(now), NULL); for (i = r->poolinfo->poolbytes; i > 0; i -= sizeof(rv)) { - if (!arch_get_random_long(&rv)) + if (!arch_get_random_seed_long(&rv) && + !arch_get_random_long(&rv)) rv = random_get_entropy(); mix_pool_bytes(r, &rv, sizeof(rv), NULL); } |