aboutsummaryrefslogtreecommitdiff
path: root/drivers/char
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/char')
-rw-r--r--drivers/char/random.c21
1 files changed, 10 insertions, 11 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c
index a754132336b..ba0d7030538 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -454,7 +454,7 @@ static void __add_entropy_words(struct entropy_store *r, const __u32 *in,
static __u32 const twist_table[8] = {
0x00000000, 0x3b6e20c8, 0x76dc4190, 0x4db26158,
0xedb88320, 0xd6d6a3e8, 0x9b64c2b0, 0xa00ae278 };
- unsigned long i, add_ptr, tap1, tap2, tap3, tap4, tap5;
+ unsigned long i, j, tap1, tap2, tap3, tap4, tap5;
int input_rotate;
int wordmask = r->poolinfo->poolwords - 1;
__u32 w;
@@ -469,19 +469,21 @@ static void __add_entropy_words(struct entropy_store *r, const __u32 *in,
spin_lock_irqsave(&r->lock, flags);
input_rotate = r->input_rotate;
- add_ptr = r->add_ptr;
+ i = r->add_ptr;
while (nwords--) {
w = rol32(*in++, input_rotate & 31);
- i = add_ptr = (add_ptr - 1) & wordmask;
+ i = (i - 1) & wordmask;
/* XOR in the various taps */
+ w ^= r->pool[i];
w ^= r->pool[(i + tap1) & wordmask];
w ^= r->pool[(i + tap2) & wordmask];
w ^= r->pool[(i + tap3) & wordmask];
w ^= r->pool[(i + tap4) & wordmask];
w ^= r->pool[(i + tap5) & wordmask];
- w ^= r->pool[i];
+
+ /* Mix the result back in with a twist */
r->pool[i] = (w >> 3) ^ twist_table[w & 7];
/*
@@ -494,14 +496,11 @@ static void __add_entropy_words(struct entropy_store *r, const __u32 *in,
}
r->input_rotate = input_rotate;
- r->add_ptr = add_ptr;
+ r->add_ptr = i;
- if (out) {
- for (i = 0; i < 16; i++) {
- out[i] = r->pool[add_ptr];
- add_ptr = (add_ptr - 1) & wordmask;
- }
- }
+ if (out)
+ for (j = 0; j < 16; j++)
+ out[j] = r->pool[(i - j) & wordmask];
spin_unlock_irqrestore(&r->lock, flags);
}