random: add tracepoints for easier debugging and verification
Theodore Ts'o [Wed, 4 Jul 2012 20:19:30 +0000 (16:19 -0400)]
commit 00ce1db1a634746040ace24c09a4e3a7949a3145 upstream.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/char/random.c
include/trace/events/random.h [new file with mode: 0644]

index ed7e283..45dd047 100644 (file)
 #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));
diff --git a/include/trace/events/random.h b/include/trace/events/random.h
new file mode 100644 (file)
index 0000000..422df19
--- /dev/null
@@ -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>