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    Subject[ 53/82] random: add tracepoints for easier debugging and verification
    Date
    From: Greg KH <gregkh@linuxfoundation.org>

    3.5-stable review patch. If anyone has any objections, please let me know.

    ------------------

    From: Theodore Ts'o <tytso@mit.edu>

    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 | 26 ++++++--
    include/trace/events/random.h | 134 ++++++++++++++++++++++++++++++++++++++++++
    2 files changed, 156 insertions(+), 4 deletions(-)

    --- a/drivers/char/random.c
    +++ b/drivers/char/random.c
    @@ -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 entr
    ((__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 e
    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 en
    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(stru
    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, in
    {
    char *p = buf;

    + trace_get_random_bytes(nbytes, _RET_IP_);
    while (nbytes) {
    unsigned long v;
    int chunk = min(nbytes, (int)sizeof(unsigned long));
    --- /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>



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