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-rw-r--r--drivers/char/random.c67
1 files changed, 30 insertions, 37 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c
index ba8d63f52c05..349beb318757 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -430,14 +430,20 @@ static int random_write_wakeup_bits = 28 * OUTPUT_POOL_WORDS;
* polynomial which improves the resulting TGFSR polynomial to be
* irreducible, which we have made here.
*/
-static const struct poolinfo {
- int poolbitshift, poolwords, poolbytes, poolfracbits;
-#define S(x) ilog2(x)+5, (x), (x)*4, (x) << (ENTROPY_SHIFT+5)
- int tap1, tap2, tap3, tap4, tap5;
-} poolinfo_table[] = {
- /* was: x^128 + x^103 + x^76 + x^51 +x^25 + x + 1 */
+enum poolinfo {
+ POOL_WORDS = 128,
+ POOL_WORDMASK = POOL_WORDS - 1,
+ POOL_BYTES = POOL_WORDS * sizeof(u32),
+ POOL_BITS = POOL_BYTES * 8,
+ POOL_BITSHIFT = ilog2(POOL_WORDS) + 5,
+ POOL_FRACBITS = POOL_WORDS << (ENTROPY_SHIFT + 5),
+
/* x^128 + x^104 + x^76 + x^51 +x^25 + x + 1 */
- { S(128), 104, 76, 51, 25, 1 },
+ POOL_TAP1 = 104,
+ POOL_TAP2 = 76,
+ POOL_TAP3 = 51,
+ POOL_TAP4 = 25,
+ POOL_TAP5 = 1
};
/*
@@ -503,7 +509,6 @@ MODULE_PARM_DESC(ratelimit_disable, "Disable random ratelimit suppression");
struct entropy_store;
struct entropy_store {
/* read-only data: */
- const struct poolinfo *poolinfo;
__u32 *pool;
const char *name;
@@ -525,7 +530,6 @@ static void crng_reseed(struct crng_state *crng, struct entropy_store *r);
static __u32 input_pool_data[INPUT_POOL_WORDS] __latent_entropy;
static struct entropy_store input_pool = {
- .poolinfo = &poolinfo_table[0],
.name = "input",
.lock = __SPIN_LOCK_UNLOCKED(input_pool.lock),
.pool = input_pool_data
@@ -548,33 +552,26 @@ static __u32 const twist_table[8] = {
static void _mix_pool_bytes(struct entropy_store *r, const void *in,
int nbytes)
{
- unsigned long i, tap1, tap2, tap3, tap4, tap5;
+ unsigned long i;
int input_rotate;
- int wordmask = r->poolinfo->poolwords - 1;
const unsigned char *bytes = in;
__u32 w;
- tap1 = r->poolinfo->tap1;
- tap2 = r->poolinfo->tap2;
- tap3 = r->poolinfo->tap3;
- tap4 = r->poolinfo->tap4;
- tap5 = r->poolinfo->tap5;
-
input_rotate = r->input_rotate;
i = r->add_ptr;
/* mix one byte at a time to simplify size handling and churn faster */
while (nbytes--) {
w = rol32(*bytes++, input_rotate);
- i = (i - 1) & wordmask;
+ i = (i - 1) & POOL_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 + POOL_TAP1) & POOL_WORDMASK];
+ w ^= r->pool[(i + POOL_TAP2) & POOL_WORDMASK];
+ w ^= r->pool[(i + POOL_TAP3) & POOL_WORDMASK];
+ w ^= r->pool[(i + POOL_TAP4) & POOL_WORDMASK];
+ w ^= r->pool[(i + POOL_TAP5) & POOL_WORDMASK];
/* Mix the result back in with a twist */
r->pool[i] = (w >> 3) ^ twist_table[w & 7];
@@ -672,7 +669,6 @@ static void process_random_ready_list(void)
static void credit_entropy_bits(struct entropy_store *r, int nbits)
{
int entropy_count, orig;
- const int pool_size = r->poolinfo->poolfracbits;
int nfrac = nbits << ENTROPY_SHIFT;
if (!nbits)
@@ -706,25 +702,25 @@ retry:
* turns no matter how large nbits is.
*/
int pnfrac = nfrac;
- const int s = r->poolinfo->poolbitshift + ENTROPY_SHIFT + 2;
+ const int s = POOL_BITSHIFT + ENTROPY_SHIFT + 2;
/* The +2 corresponds to the /4 in the denominator */
do {
- unsigned int anfrac = min(pnfrac, pool_size/2);
+ unsigned int anfrac = min(pnfrac, POOL_FRACBITS/2);
unsigned int add =
- ((pool_size - entropy_count)*anfrac*3) >> s;
+ ((POOL_FRACBITS - entropy_count)*anfrac*3) >> s;
entropy_count += add;
pnfrac -= anfrac;
- } while (unlikely(entropy_count < pool_size-2 && pnfrac));
+ } while (unlikely(entropy_count < POOL_FRACBITS-2 && pnfrac));
}
if (WARN_ON(entropy_count < 0)) {
pr_warn("negative entropy/overflow: pool %s count %d\n",
r->name, entropy_count);
entropy_count = 0;
- } else if (entropy_count > pool_size)
- entropy_count = pool_size;
+ } else if (entropy_count > POOL_FRACBITS)
+ entropy_count = POOL_FRACBITS;
if (cmpxchg(&r->entropy_count, orig, entropy_count) != orig)
goto retry;
@@ -741,13 +737,11 @@ retry:
static int credit_entropy_bits_safe(struct entropy_store *r, int nbits)
{
- const int nbits_max = r->poolinfo->poolwords * 32;
-
if (nbits < 0)
return -EINVAL;
/* Cap the value to avoid overflows */
- nbits = min(nbits, nbits_max);
+ nbits = min(nbits, POOL_BITS);
credit_entropy_bits(r, nbits);
return 0;
@@ -1343,7 +1337,7 @@ static size_t account(struct entropy_store *r, size_t nbytes, int min,
int entropy_count, orig, have_bytes;
size_t ibytes, nfrac;
- BUG_ON(r->entropy_count > r->poolinfo->poolfracbits);
+ BUG_ON(r->entropy_count > POOL_FRACBITS);
/* Can we pull enough? */
retry:
@@ -1409,8 +1403,7 @@ static void extract_buf(struct entropy_store *r, __u8 *out)
/* Generate a hash across the pool */
spin_lock_irqsave(&r->lock, flags);
- blake2s_update(&state, (const u8 *)r->pool,
- r->poolinfo->poolwords * sizeof(*r->pool));
+ blake2s_update(&state, (const u8 *)r->pool, POOL_BYTES);
blake2s_final(&state, hash); /* final zeros out state */
/*
@@ -1766,7 +1759,7 @@ static void __init init_std_data(struct entropy_store *r)
unsigned long rv;
mix_pool_bytes(r, &now, sizeof(now));
- for (i = r->poolinfo->poolbytes; i > 0; i -= sizeof(rv)) {
+ for (i = POOL_BYTES; i > 0; i -= sizeof(rv)) {
if (!arch_get_random_seed_long(&rv) &&
!arch_get_random_long(&rv))
rv = random_get_entropy();
generated by cgit v1.2.3 (git 2.39.0) at 2024-07-28 16:03:40 +0300