diff options
| author | Theodore Ts'o <tytso@mit.edu> | 2013-09-21 13:58:22 -0400 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2013-11-28 14:02:03 +0000 |
| commit | ee698d67a4af1fd37ba5b40733f103a62f223774 (patch) | |
| tree | 37238290039918cfdc4765548ae8dd5e026cbcf4 /drivers | |
| parent | 52d4f668a2ebb3d33b2ece452d4f3bcec6c87b7d (diff) | |
random: allow architectures to optionally define random_get_entropy()
commit 61875f30daf60305712e25b209ef41ced2635bad upstream.
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>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'drivers')
| -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 9502185198dd..c244f0ed61d6 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -668,7 +668,7 @@ static void set_timer_rand_state(unsigned int irq, */ 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); @@ -705,7 +705,7 @@ 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); @@ -772,7 +772,7 @@ 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; @@ -1503,7 +1503,7 @@ 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); |