random: add tracepoints for easier debugging and verification

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

View File

@ -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));

View File

@ -0,0 +1,134 @@
#undef TRACE_SYSTEM
#define TRACE_SYSTEM random
#if !defined(_TRACE_RANDOM_H) || defined(TRACE_HEADER_MULTI_READ)
#define _TRACE_RANDOM_H
#include <linux/writeback.h>
#include <linux/tracepoint.h>
DECLARE_EVENT_CLASS(random__mix_pool_bytes,
TP_PROTO(const char *pool_name, int bytes, unsigned long IP),
TP_ARGS(pool_name, bytes, IP),
TP_STRUCT__entry(
__field( const char *, pool_name )
__field( int, bytes )
__field(unsigned long, IP )
),
TP_fast_assign(
__entry->pool_name = pool_name;
__entry->bytes = bytes;
__entry->IP = IP;
),
TP_printk("%s pool: bytes %d caller %pF",
__entry->pool_name, __entry->bytes, (void *)__entry->IP)
);
DEFINE_EVENT(random__mix_pool_bytes, mix_pool_bytes,
TP_PROTO(const char *pool_name, int bytes, unsigned long IP),
TP_ARGS(pool_name, bytes, IP)
);
DEFINE_EVENT(random__mix_pool_bytes, mix_pool_bytes_nolock,
TP_PROTO(const char *pool_name, int bytes, unsigned long IP),
TP_ARGS(pool_name, bytes, IP)
);
TRACE_EVENT(credit_entropy_bits,
TP_PROTO(const char *pool_name, int bits, int entropy_count,
int entropy_total, unsigned long IP),
TP_ARGS(pool_name, bits, entropy_count, entropy_total, IP),
TP_STRUCT__entry(
__field( const char *, pool_name )
__field( int, bits )
__field( int, entropy_count )
__field( int, entropy_total )
__field(unsigned long, IP )
),
TP_fast_assign(
__entry->pool_name = pool_name;
__entry->bits = bits;
__entry->entropy_count = entropy_count;
__entry->entropy_total = entropy_total;
__entry->IP = IP;
),
TP_printk("%s pool: bits %d entropy_count %d entropy_total %d "
"caller %pF", __entry->pool_name, __entry->bits,
__entry->entropy_count, __entry->entropy_total,
(void *)__entry->IP)
);
TRACE_EVENT(get_random_bytes,
TP_PROTO(int nbytes, unsigned long IP),
TP_ARGS(nbytes, IP),
TP_STRUCT__entry(
__field( int, nbytes )
__field(unsigned long, IP )
),
TP_fast_assign(
__entry->nbytes = nbytes;
__entry->IP = IP;
),
TP_printk("nbytes %d caller %pF", __entry->nbytes, (void *)__entry->IP)
);
DECLARE_EVENT_CLASS(random__extract_entropy,
TP_PROTO(const char *pool_name, int nbytes, int entropy_count,
unsigned long IP),
TP_ARGS(pool_name, nbytes, entropy_count, IP),
TP_STRUCT__entry(
__field( const char *, pool_name )
__field( int, nbytes )
__field( int, entropy_count )
__field(unsigned long, IP )
),
TP_fast_assign(
__entry->pool_name = pool_name;
__entry->nbytes = nbytes;
__entry->entropy_count = entropy_count;
__entry->IP = IP;
),
TP_printk("%s pool: nbytes %d entropy_count %d caller %pF",
__entry->pool_name, __entry->nbytes, __entry->entropy_count,
(void *)__entry->IP)
);
DEFINE_EVENT(random__extract_entropy, extract_entropy,
TP_PROTO(const char *pool_name, int nbytes, int entropy_count,
unsigned long IP),
TP_ARGS(pool_name, nbytes, entropy_count, IP)
);
DEFINE_EVENT(random__extract_entropy, extract_entropy_user,
TP_PROTO(const char *pool_name, int nbytes, int entropy_count,
unsigned long IP),
TP_ARGS(pool_name, nbytes, entropy_count, IP)
);
#endif /* _TRACE_RANDOM_H */
/* This part must be outside protection */
#include <trace/define_trace.h>