[PATCH 09/12] random: add tracepoints for easier debugging and verification

Theodore Ts'o
2012-07-06T22:46:46Z

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
---
drivers/char/random.c | 26 ++++++--
include/trace/events/random.h | 134 ++++++++++++++++++++++++++++++++++++++++++
2 files changed, 156 insertions(+), 4 deletions(-)
create mode 100644 include/trace/events/random.h

diff --git a/drivers/char/random.c b/drivers/char/random.c
index 79c105a..aaf4629 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -265,6 +265,9 @@
#include <asm/irq_regs.h>
#include <asm/io.h>

+#define CREATE_TRACE_POINTS
+#include <trace/events/random.h>
+
/*
* Configuration information
*/
@@ -477,8 +480,8 @@ 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;
@@ -530,13 +533,21 @@ 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);
}

@@ -584,6 +595,7 @@ 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;
@@ -598,6 +610,9 @@ 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);
@@ -969,6 +984,7 @@ 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);

@@ -1003,6 +1019,7 @@ 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);

@@ -1060,6 +1077,7 @@ 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));
diff --git a/include/trace/events/random.h b/include/trace/events/random.h
new file mode 100644
index 0000000..422df19
--- /dev/null
+++ b/include/trace/events/random.h
@@ -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>
--
1.7.11.1.108.gb129051