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| author | Theodore Ts'o <tytso@mit.edu> | 2013-09-21 21:58:22 +0400 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2013-10-10 22:30:53 +0400 |
| commit | 61875f30daf60305712e25b209ef41ced2635bad (patch) | |
| tree | 176cda3ae729c520bff1b0f6a19806c18c0a7523 /drivers/char | |
| parent | 47d06e532e95b71c0db3839ebdef3fe8812fca2c (diff) | |
| download | linux-61875f30daf60305712e25b209ef41ced2635bad.tar.xz | |
random: allow architectures to optionally define random_get_entropy()
Allow architectures which have a disabled get_cycles() function to
provide a random_get_entropy() function which provides a fine-grained,
rapidly changing counter that can be used by the /dev/random driver.
For example, an architecture might have a rapidly changing register
used to control random TLB cache eviction, or DRAM refresh that
doesn't meet the requirements of get_cycles(), but which is good
enough for the needs of the random driver.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@vger.kernel.org
Diffstat (limited to 'drivers/char')
| -rw-r--r-- | drivers/char/random.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c index 92e6c67e1ae6..2d5daf9b58e9 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -643,7 +643,7 @@ struct timer_rand_state { */ void add_device_randomness(const void *buf, unsigned int size) { - unsigned long time = get_cycles() ^ jiffies; + unsigned long time = random_get_entropy() ^ jiffies; mix_pool_bytes(&input_pool, buf, size, NULL); mix_pool_bytes(&input_pool, &time, sizeof(time), NULL); @@ -680,7 +680,7 @@ static void add_timer_randomness(struct timer_rand_state *state, unsigned num) goto out; sample.jiffies = jiffies; - sample.cycles = get_cycles(); + sample.cycles = random_get_entropy(); sample.num = num; mix_pool_bytes(&input_pool, &sample, sizeof(sample), NULL); @@ -747,7 +747,7 @@ void add_interrupt_randomness(int irq, int irq_flags) struct fast_pool *fast_pool = &__get_cpu_var(irq_randomness); struct pt_regs *regs = get_irq_regs(); unsigned long now = jiffies; - __u32 input[4], cycles = get_cycles(); + __u32 input[4], cycles = random_get_entropy(); input[0] = cycles ^ jiffies; input[1] = irq; @@ -1485,7 +1485,7 @@ unsigned int get_random_int(void) hash = get_cpu_var(get_random_int_hash); - hash[0] += current->pid + jiffies + get_cycles(); + hash[0] += current->pid + jiffies + random_get_entropy(); md5_transform(hash, random_int_secret); ret = hash[0]; put_cpu_var(get_random_int_hash); |