diff options
| -rw-r--r-- | drivers/char/random.c | 44 |
1 files changed, 23 insertions, 21 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c index 0a7ac0a7b252..922a2e4089f9 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -495,9 +495,8 @@ static void _mix_pool_bytes(struct entropy_store *r, const void *in, tap4 = r->poolinfo->tap4; tap5 = r->poolinfo->tap5; - smp_rmb(); - input_rotate = ACCESS_ONCE(r->input_rotate); - i = ACCESS_ONCE(r->add_ptr); + input_rotate = r->input_rotate; + i = r->add_ptr; /* mix one byte at a time to simplify size handling and churn faster */ while (nbytes--) { @@ -524,9 +523,8 @@ static void _mix_pool_bytes(struct entropy_store *r, const void *in, input_rotate = (input_rotate + (i ? 7 : 14)) & 31; } - ACCESS_ONCE(r->input_rotate) = input_rotate; - ACCESS_ONCE(r->add_ptr) = i; - smp_wmb(); + r->input_rotate = input_rotate; + r->add_ptr = i; if (out) for (j = 0; j < 16; j++) @@ -845,7 +843,7 @@ void add_interrupt_randomness(int irq, int irq_flags) __u32 input[4], c_high, j_high; __u64 ip; unsigned long seed; - int credit; + int credit = 0; c_high = (sizeof(cycles) > 4) ? cycles >> 32 : 0; j_high = (sizeof(now) > 4) ? now >> 32 : 0; @@ -860,36 +858,40 @@ void add_interrupt_randomness(int irq, int irq_flags) if ((fast_pool->count & 63) && !time_after(now, fast_pool->last + HZ)) return; - fast_pool->last = now; - r = nonblocking_pool.initialized ? &input_pool : &nonblocking_pool; + if (!spin_trylock(&r->lock)) { + fast_pool->count--; + return; + } + fast_pool->last = now; __mix_pool_bytes(r, &fast_pool->pool, sizeof(fast_pool->pool), NULL); /* + * 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; + } + spin_unlock(&r->lock); + + /* * If we don't have a valid cycle counter, and we see * back-to-back timer interrupts, then skip giving credit for * any entropy, otherwise credit 1 bit. */ - credit = 1; + credit++; if (cycles == 0) { if (irq_flags & __IRQF_TIMER) { if (fast_pool->last_timer_intr) - credit = 0; + credit--; fast_pool->last_timer_intr = 1; } else fast_pool->last_timer_intr = 0; } - /* - * 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); } |