Merge branch 'x86-rdrand-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

* 'x86-rdrand-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  random: Use arch_get_random_int instead of cycle counter if avail

1 files changed, 6 insertions, 2 deletions

diff --git a/drivers/char/random.c b/drivers/char/random.c
index 6035ab8d5ef7..85da8740586b 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -624,8 +624,8 @@ static struct timer_rand_state input_timer_state;
 static void add_timer_randomness(struct timer_rand_state *state, unsigned num)
 {
         struct {
-                cycles_t cycles;
                 long jiffies;
+                unsigned cycles;
                 unsigned num;
         } sample;
         long delta, delta2, delta3;
@@ -637,7 +637,11 @@ static void add_timer_randomness(struct timer_rand_state *state, unsigned num)
                 goto out;
 
         sample.jiffies = jiffies;
-        sample.cycles = get_cycles();
+
+        /* Use arch random value, fall back to cycles */
+        if (!arch_get_random_int(&sample.cycles))
+                sample.cycles = get_cycles();
+
         sample.num = num;
         mix_pool_bytes(&input_pool, &sample, sizeof(sample));