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Commit ca99f246 authored by Matt Mackall's avatar Matt Mackall Committed by Linus Torvalds
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[PATCH] random: Static allocation of pools 

As we no longer allow resizing of pools, it makes sense to allocate and
initialize them statically.  Remove create_entropy_store and simplify
rand_initialize.
Signed-off-by: default avatarMatt Mackall <mpm@selenic.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 8099b8c1
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Inline Side-by-side
Showing with 78 additions and 123 deletions
drivers/char/random.c
View file @ ca99f246
......@@ -295,42 +295,37 @@ static struct poolinfo {
int poolwords;
int tap1, tap2, tap3, tap4, tap5;
} poolinfo_table[] = {
/* x^128 + x^103 + x^76 + x^51 +x^25 + x + 1 -- 105 */
{ 128, 103, 76, 51, 25, 1 },
/* x^32 + x^26 + x^20 + x^14 + x^7 + x + 1 -- 15 */
{ 32, 26, 20, 14, 7, 1 },
#if 0
/* x^2048 + x^1638 + x^1231 + x^819 + x^411 + x + 1 -- 115 */
{ 2048, 1638, 1231, 819, 411, 1 },
/* x^1024 + x^817 + x^615 + x^412 + x^204 + x + 1 -- 290 */
{ 1024, 817, 615, 412, 204, 1 },
#if 0 /* Alternate polynomial */
/* x^1024 + x^819 + x^616 + x^410 + x^207 + x^2 + 1 -- 115 */
{ 1024, 819, 616, 410, 207, 2 },
#endif
/* x^512 + x^411 + x^308 + x^208 + x^104 + x + 1 -- 225 */
{ 512, 411, 308, 208, 104, 1 },
#if 0 /* Alternates */
/* x^512 + x^409 + x^307 + x^206 + x^102 + x^2 + 1 -- 95 */
{ 512, 409, 307, 206, 102, 2 },
/* x^512 + x^409 + x^309 + x^205 + x^103 + x^2 + 1 -- 95 */
{ 512, 409, 309, 205, 103, 2 },
#endif
/* x^256 + x^205 + x^155 + x^101 + x^52 + x + 1 -- 125 */
{ 256, 205, 155, 101, 52, 1 },
/* x^128 + x^103 + x^76 + x^51 +x^25 + x + 1 -- 105 */
{ 128, 103, 76, 51, 25, 1 },
#if 0 /* Alternate polynomial */
/* x^128 + x^103 + x^78 + x^51 + x^27 + x^2 + 1 -- 70 */
{ 128, 103, 78, 51, 27, 2 },
#endif
/* x^64 + x^52 + x^39 + x^26 + x^14 + x + 1 -- 15 */
{ 64, 52, 39, 26, 14, 1 },
/* x^32 + x^26 + x^20 + x^14 + x^7 + x + 1 -- 15 */
{ 32, 26, 20, 14, 7, 1 },
{ 0, 0, 0, 0, 0, 0 },
#endif
};
#define POOLBITS poolwords*32
......@@ -382,9 +377,6 @@ static struct poolinfo {
/*
* Static global variables
*/
static struct entropy_store *input_pool; /* The default global store */
static struct entropy_store *blocking_pool; /* secondary store */
static struct entropy_store *nonblocking_pool; /* For urandom */
static DECLARE_WAIT_QUEUE_HEAD(random_read_wait);
static DECLARE_WAIT_QUEUE_HEAD(random_write_wait);
......@@ -392,7 +384,8 @@ static DECLARE_WAIT_QUEUE_HEAD(random_write_wait);
* Forward procedure declarations
*/
#ifdef CONFIG_SYSCTL
static void sysctl_init_random(struct entropy_store *random_state);
struct entropy_store;
static void sysctl_init_random(struct entropy_store *pool);
#endif
static inline __u32 rol32(__u32 word, int shift)
......@@ -406,9 +399,9 @@ module_param(debug, bool, 0644);
#define DEBUG_ENT(fmt, arg...) do { if (debug) \
printk(KERN_DEBUG "random %04d %04d %04d: " \
fmt,\
input_pool->entropy_count,\
blocking_pool->entropy_count,\
nonblocking_pool->entropy_count,\
input_pool.entropy_count,\
blocking_pool.entropy_count,\
nonblocking_pool.entropy_count,\
## arg); } while (0)
#else
#define DEBUG_ENT(fmt, arg...) do {} while (0)
......@@ -423,7 +416,7 @@ module_param(debug, bool, 0644);
struct entropy_store {
/* mostly-read data: */
struct poolinfo poolinfo;
struct poolinfo *poolinfo;
__u32 *pool;
const char *name;
......@@ -434,48 +427,30 @@ struct entropy_store {
int input_rotate;
};
/*
* Initialize the entropy store. The input argument is the size of
* the random pool.
*
* Returns an negative error if there is a problem.
*/
static int create_entropy_store(int size, const char *name,
struct entropy_store **ret_bucket)
{
struct entropy_store *r;
struct poolinfo *p;
int poolwords;
poolwords = (size + 3) / 4; /* Convert bytes->words */
/* The pool size must be a multiple of 16 32-bit words */
poolwords = ((poolwords + 15) / 16) * 16;
for (p = poolinfo_table; p->poolwords; p++) {
if (poolwords == p->poolwords)
break;
}
if (p->poolwords == 0)
return -EINVAL;
static __u32 input_pool_data[INPUT_POOL_WORDS];
static __u32 blocking_pool_data[OUTPUT_POOL_WORDS];
static __u32 nonblocking_pool_data[OUTPUT_POOL_WORDS];
r = kmalloc(sizeof(struct entropy_store), GFP_KERNEL);
if (!r)
return -ENOMEM;
static struct entropy_store input_pool = {
.poolinfo = &poolinfo_table[0],
.name = "input",
.lock = SPIN_LOCK_UNLOCKED,
.pool = input_pool_data
};
memset (r, 0, sizeof(struct entropy_store));
r->poolinfo = *p;
static struct entropy_store blocking_pool = {
.poolinfo = &poolinfo_table[1],
.name = "blocking",
.lock = SPIN_LOCK_UNLOCKED,
.pool = blocking_pool_data
};
r->pool = kmalloc(POOLBYTES, GFP_KERNEL);
if (!r->pool) {
kfree(r);
return -ENOMEM;
}
memset(r->pool, 0, POOLBYTES);
spin_lock_init(&r->lock);
r->name = name;
*ret_bucket = r;
return 0;
}
static struct entropy_store nonblocking_pool = {
.poolinfo = &poolinfo_table[1],
.name = "nonblocking",
.lock = SPIN_LOCK_UNLOCKED,
.pool = nonblocking_pool_data
};
/*
* This function adds a byte into the entropy "pool". It does not
......@@ -495,16 +470,16 @@ static void __add_entropy_words(struct entropy_store *r, const __u32 *in,
0xedb88320, 0xd6d6a3e8, 0x9b64c2b0, 0xa00ae278 };
unsigned long i, add_ptr, tap1, tap2, tap3, tap4, tap5;
int new_rotate, input_rotate;
int wordmask = r->poolinfo.poolwords - 1;
int wordmask = r->poolinfo->poolwords - 1;
__u32 w, next_w;
unsigned long flags;
/* Taps are constant, so we can load them without holding r->lock. */
tap1 = r->poolinfo.tap1;
tap2 = r->poolinfo.tap2;
tap3 = r->poolinfo.tap3;
tap4 = r->poolinfo.tap4;
tap5 = r->poolinfo.tap5;
tap1 = r->poolinfo->tap1;
tap2 = r->poolinfo->tap2;
tap3 = r->poolinfo->tap3;
tap4 = r->poolinfo->tap4;
tap5 = r->poolinfo->tap5;
next_w = *in++;
spin_lock_irqsave(&r->lock, flags);
......@@ -570,8 +545,8 @@ static void credit_entropy_store(struct entropy_store *r, int nbits)
DEBUG_ENT("negative entropy/overflow (%d+%d)\n",
r->entropy_count, nbits);
r->entropy_count = 0;
} else if (r->entropy_count + nbits > r->poolinfo.POOLBITS) {
r->entropy_count = r->poolinfo.POOLBITS;
} else if (r->entropy_count + nbits > r->poolinfo->POOLBITS) {
r->entropy_count = r->poolinfo->POOLBITS;
} else {
r->entropy_count += nbits;
if (nbits)
......@@ -660,7 +635,7 @@ static void batch_entropy_store(u32 a, u32 b, int num)
static void batch_entropy_process(void *private_)
{
struct entropy_store *r = (struct entropy_store *) private_, *p;
int max_entropy = r->poolinfo.POOLBITS;
int max_entropy = r->poolinfo->POOLBITS;
unsigned head, tail;
/* Mixing into the pool is expensive, so copy over the batch
......@@ -682,8 +657,9 @@ static void batch_entropy_process(void *private_)
p = r;
while (head != tail) {
if (r->entropy_count >= max_entropy) {
r = (r == blocking_pool) ? input_pool : blocking_pool;
max_entropy = r->poolinfo.POOLBITS;
r = (r == &blocking_pool) ? &input_pool :
&blocking_pool;
max_entropy = r->poolinfo->POOLBITS;
}
add_entropy_words(r, batch_entropy_copy[tail].data, 2);
credit_entropy_store(r, batch_entropy_copy[tail].credit);
......@@ -727,7 +703,7 @@ static void add_timer_randomness(struct timer_rand_state *state, unsigned num)
preempt_disable();
/* if over the trickle threshold, use only 1 in 4096 samples */
if (input_pool->entropy_count > trickle_thresh &&
if (input_pool.entropy_count > trickle_thresh &&
(__get_cpu_var(trickle_count)++ & 0xfff))
goto out;
......@@ -1226,7 +1202,7 @@ static inline void xfer_secondary_pool(struct entropy_store *r,
size_t nbytes, __u32 *tmp)
{
if (r->entropy_count < nbytes * 8 &&
r->entropy_count < r->poolinfo.POOLBITS) {
r->entropy_count < r->poolinfo->POOLBITS) {
int bytes = max_t(int, random_read_wakeup_thresh / 8,
min_t(int, nbytes, TMP_BUF_SIZE));
......@@ -1234,7 +1210,7 @@ static inline void xfer_secondary_pool(struct entropy_store *r,
"(%d of %d requested)\n",
r->name, bytes * 8, nbytes * 8, r->entropy_count);
bytes=extract_entropy(input_pool, tmp, bytes,
bytes=extract_entropy(&input_pool, tmp, bytes,
EXTRACT_ENTROPY_LIMIT);
add_entropy_words(r, tmp, (bytes + 3) / 4);
credit_entropy_store(r, bytes*8);
......@@ -1263,8 +1239,8 @@ static ssize_t extract_entropy(struct entropy_store *r, void * buf,
unsigned long cpuflags;
/* Redundant, but just in case... */
if (r->entropy_count > r->poolinfo.POOLBITS)
r->entropy_count = r->poolinfo.POOLBITS;
if (r->entropy_count > r->poolinfo->POOLBITS)
r->entropy_count = r->poolinfo->POOLBITS;
if (flags & EXTRACT_ENTROPY_SECONDARY)
xfer_secondary_pool(r, nbytes, tmp);
......@@ -1323,7 +1299,7 @@ static ssize_t extract_entropy(struct entropy_store *r, void * buf,
* attempts to find previous ouputs), unless the hash
* function can be inverted.
*/
for (i = 0, x = 0; i < r->poolinfo.poolwords; i += 16, x+=2) {
for (i = 0, x = 0; i < r->poolinfo->poolwords; i += 16, x+=2) {
HASH_TRANSFORM(tmp, r->pool+i);
add_entropy_words(r, &tmp[x%HASH_BUFFER_SIZE], 1);
}
......@@ -1377,21 +1353,8 @@ static ssize_t extract_entropy(struct entropy_store *r, void * buf,
*/
void get_random_bytes(void *buf, int nbytes)
{
struct entropy_store *r = nonblocking_pool;
int flags = EXTRACT_ENTROPY_SECONDARY;
if (!r)
r = blocking_pool;
if (!r) {
r = input_pool;
flags = 0;
}
if (!r) {
printk(KERN_NOTICE "get_random_bytes called before "
"random driver initialization\n");
return;
}
extract_entropy(r, (char *) buf, nbytes, flags);
extract_entropy(&nonblocking_pool, (char *) buf, nbytes,
EXTRACT_ENTROPY_SECONDARY);
}
EXPORT_SYMBOL(get_random_bytes);
......@@ -1422,21 +1385,13 @@ static void init_std_data(struct entropy_store *r)
static int __init rand_initialize(void)
{
if (create_entropy_store(INPUT_POOL_WORDS, "input", &input_pool))
goto err;
if (batch_entropy_init(BATCH_ENTROPY_SIZE, input_pool))
goto err;
if (create_entropy_store(OUTPUT_POOL_WORDS, "blocking",
&blocking_pool))
goto err;
if (create_entropy_store(OUTPUT_POOL_WORDS, "nonblocking",
&nonblocking_pool))
if (batch_entropy_init(BATCH_ENTROPY_SIZE, &input_pool))
goto err;
init_std_data(input_pool);
init_std_data(blocking_pool);
init_std_data(nonblocking_pool);
init_std_data(&input_pool);
init_std_data(&blocking_pool);
init_std_data(&nonblocking_pool);
#ifdef CONFIG_SYSCTL
sysctl_init_random(input_pool);
sysctl_init_random(&input_pool);
#endif
return 0;
err:
......@@ -1492,7 +1447,7 @@ random_read(struct file * file, char __user * buf, size_t nbytes, loff_t *ppos)
DEBUG_ENT("reading %d bits\n", n*8);
n = extract_entropy(blocking_pool, buf, n,
n = extract_entropy(&blocking_pool, buf, n,
EXTRACT_ENTROPY_USER |
EXTRACT_ENTROPY_LIMIT |
EXTRACT_ENTROPY_SECONDARY);
......@@ -1509,7 +1464,7 @@ random_read(struct file * file, char __user * buf, size_t nbytes, loff_t *ppos)
DEBUG_ENT("sleeping?\n");
wait_event_interruptible(random_read_wait,
input_pool->entropy_count >=
input_pool.entropy_count >=
random_read_wakeup_thresh);
DEBUG_ENT("awake\n");
......@@ -1549,12 +1504,12 @@ urandom_read(struct file * file, char __user * buf,
int flags = EXTRACT_ENTROPY_USER;
unsigned long cpuflags;
spin_lock_irqsave(&input_pool->lock, cpuflags);
if (input_pool->entropy_count > input_pool->poolinfo.POOLBITS)
spin_lock_irqsave(&input_pool.lock, cpuflags);
if (input_pool.entropy_count > input_pool.poolinfo->POOLBITS)
flags |= EXTRACT_ENTROPY_SECONDARY;
spin_unlock_irqrestore(&input_pool->lock, cpuflags);
spin_unlock_irqrestore(&input_pool.lock, cpuflags);
return extract_entropy(nonblocking_pool, buf, nbytes, flags);
return extract_entropy(&nonblocking_pool, buf, nbytes, flags);
}
static unsigned int
......@@ -1565,9 +1520,9 @@ random_poll(struct file *file, poll_table * wait)
poll_wait(file, &random_read_wait, wait);
poll_wait(file, &random_write_wait, wait);
mask = 0;
if (input_pool->entropy_count >= random_read_wakeup_thresh)
if (input_pool.entropy_count >= random_read_wakeup_thresh)
mask |= POLLIN | POLLRDNORM;
if (input_pool->entropy_count < random_write_wakeup_thresh)
if (input_pool.entropy_count < random_write_wakeup_thresh)
mask |= POLLOUT | POLLWRNORM;
return mask;
}
......@@ -1593,7 +1548,7 @@ random_write(struct file * file, const char __user * buffer,
c -= bytes;
p += bytes;
add_entropy_words(input_pool, buf, (bytes + 3) / 4);
add_entropy_words(&input_pool, buf, (bytes + 3) / 4);
}
if (p == buffer) {
return (ssize_t)ret;
......@@ -1615,7 +1570,7 @@ random_ioctl(struct inode * inode, struct file * file,
switch (cmd) {
case RNDGETENTCNT:
ent_count = input_pool->entropy_count;
ent_count = input_pool.entropy_count;
if (put_user(ent_count, p))
return -EFAULT;
return 0;
......@@ -1624,12 +1579,12 @@ random_ioctl(struct inode * inode, struct file * file,
return -EPERM;
if (get_user(ent_count, p))
return -EFAULT;
credit_entropy_store(input_pool, ent_count);
credit_entropy_store(&input_pool, ent_count);
/*
* Wake up waiting processes if we have enough
* entropy.
*/
if (input_pool->entropy_count >= random_read_wakeup_thresh)
if (input_pool.entropy_count >= random_read_wakeup_thresh)
wake_up_interruptible(&random_read_wait);
return 0;
case RNDADDENTROPY:
......@@ -1645,12 +1600,12 @@ random_ioctl(struct inode * inode, struct file * file,
size, &file->f_pos);
if (retval < 0)
return retval;
credit_entropy_store(input_pool, ent_count);
credit_entropy_store(&input_pool, ent_count);
/*
* Wake up waiting processes if we have enough
* entropy.
*/
if (input_pool->entropy_count >= random_read_wakeup_thresh)
if (input_pool.entropy_count >= random_read_wakeup_thresh)
wake_up_interruptible(&random_read_wait);
return 0;
case RNDZAPENTCNT:
......@@ -1658,9 +1613,9 @@ random_ioctl(struct inode * inode, struct file * file,
/* Clear the entropy pool counters. */
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
init_std_data(input_pool);
init_std_data(blocking_pool);
init_std_data(nonblocking_pool);
init_std_data(&input_pool);
init_std_data(&blocking_pool);
init_std_data(&nonblocking_pool);
return 0;
default:
return -EINVAL;
......@@ -1843,7 +1798,7 @@ static void sysctl_init_random(struct entropy_store *pool)
{
min_read_thresh = 8;
min_write_thresh = 0;
max_read_thresh = max_write_thresh = pool->poolinfo.POOLBITS;
max_read_thresh = max_write_thresh = pool->poolinfo->POOLBITS;
random_table[1].data = &pool->entropy_count;
}
#endif /* CONFIG_SYSCTL */
......
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