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random: add tracepoints for easier debugging and verification

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Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This commit is contained in:
Theodore Ts'o
2012-07-04 16:19:30 -04:00
parent c2557a303a
commit 00ce1db1a6
2 changed files with 156 additions and 4 deletions
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26
drivers/char/random.c
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@@ -266,6 +266,9 @@
#include <asm/irq_regs.h>
#include <asm/io.h>
#define CREATE_TRACE_POINTS
#include <trace/events/random.h>
/*
* Configuration information
*/
@@ -478,8 +481,8 @@ static __u32 const twist_table[8] = {
* it's cheap to do so and helps slightly in the expected case where
* the entropy is concentrated in the low-order bits.
*/
static void __mix_pool_bytes(struct entropy_store *r, const void *in,
int nbytes, __u8 out[64])
static void _mix_pool_bytes(struct entropy_store *r, const void *in,
int nbytes, __u8 out[64])
{
unsigned long i, j, tap1, tap2, tap3, tap4, tap5;
int input_rotate;
@@ -531,13 +534,21 @@ static void __mix_pool_bytes(struct entropy_store *r, const void *in,
((__u32 *)out)[j] = r->pool[(i - j) & wordmask];
}
static void mix_pool_bytes(struct entropy_store *r, const void *in,
static void __mix_pool_bytes(struct entropy_store *r, const void *in,
int nbytes, __u8 out[64])
{
trace_mix_pool_bytes_nolock(r->name, nbytes, _RET_IP_);
_mix_pool_bytes(r, in, nbytes, out);
}
static void mix_pool_bytes(struct entropy_store *r, const void *in,
int nbytes, __u8 out[64])
{
unsigned long flags;
trace_mix_pool_bytes(r->name, nbytes, _RET_IP_);
spin_lock_irqsave(&r->lock, flags);
__mix_pool_bytes(r, in, nbytes, out);
_mix_pool_bytes(r, in, nbytes, out);
spin_unlock_irqrestore(&r->lock, flags);
}
@@ -585,6 +596,7 @@ static void credit_entropy_bits(struct entropy_store *r, int nbits)
retry:
entropy_count = orig = ACCESS_ONCE(r->entropy_count);
entropy_count += nbits;
if (entropy_count < 0) {
DEBUG_ENT("negative entropy/overflow\n");
entropy_count = 0;
@@ -599,6 +611,9 @@ retry:
r->initialized = 1;
}
trace_credit_entropy_bits(r->name, nbits, entropy_count,
r->entropy_total, _RET_IP_);
/* should we wake readers? */
if (r == &input_pool && entropy_count >= random_read_wakeup_thresh) {
wake_up_interruptible(&random_read_wait);
@@ -971,6 +986,7 @@ static ssize_t extract_entropy(struct entropy_store *r, void *buf,
ssize_t ret = 0, i;
__u8 tmp[EXTRACT_SIZE];
trace_extract_entropy(r->name, nbytes, r->entropy_count, _RET_IP_);
xfer_secondary_pool(r, nbytes);
nbytes = account(r, nbytes, min, reserved);
@@ -1005,6 +1021,7 @@ static ssize_t extract_entropy_user(struct entropy_store *r, void __user *buf,
ssize_t ret = 0, i;
__u8 tmp[EXTRACT_SIZE];
trace_extract_entropy_user(r->name, nbytes, r->entropy_count, _RET_IP_);
xfer_secondary_pool(r, nbytes);
nbytes = account(r, nbytes, 0, 0);
@@ -1062,6 +1079,7 @@ void get_random_bytes_arch(void *buf, int nbytes)
{
char *p = buf;
trace_get_random_bytes(nbytes, _RET_IP_);
while (nbytes) {
unsigned long v;
int chunk = min(nbytes, (int)sizeof(unsigned long));