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Merge branch 'for-next/random' into for-next/core

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Avoid calling arch_get_random_seed_long() from add_interrupt_randomness()
as this can result in a firmware call on some arm64 systems.

* for-next/random:
  random: avoid arch_get_random_seed_long() when collecting IRQ randomness
This commit is contained in:
Will Deacon 2021-02-12 15:11:11 +00:00
commit cf6a85a850
1 changed files with 1 additions and 14 deletions
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15
drivers/char/random.c
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@ -1261,8 +1261,6 @@ void add_interrupt_randomness(int irq, int irq_flags)
cycles_t cycles = random_get_entropy();
__u32 c_high, j_high;
__u64 ip;
unsigned long seed;
int credit = 0;
if (cycles == 0)
cycles = get_reg(fast_pool, regs);
@ -1298,23 +1296,12 @@ void add_interrupt_randomness(int irq, int irq_flags)
fast_pool->last = now;
__mix_pool_bytes(r, &fast_pool->pool, sizeof(fast_pool->pool));
/*
* If we have architectural seed generator, produce a seed and
* add it to the pool. For the sake of paranoia don't let the
* architectural seed generator dominate the input from the
* interrupt noise.
*/
if (arch_get_random_seed_long(&seed)) {
__mix_pool_bytes(r, &seed, sizeof(seed));
credit = 1;
}
spin_unlock(&r->lock);
fast_pool->count = 0;
/* award one bit for the contents of the fast pool */
credit_entropy_bits(r, credit + 1);
credit_entropy_bits(r, 1);
}
EXPORT_SYMBOL_GPL(add_interrupt_randomness);