random: fix up sparse warnings

Add extern and static declarations to suppress sparse warnings

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Chet Kener <Cl3Kener@gmail.com>
random: fix debug format strings

Fix the following warnings in formatting debug output:

drivers/char/random.c: In function ‘xfer_secondary_pool’:
drivers/char/random.c:827: warning: format ‘%d’ expects type ‘int’, but argument 7 has type ‘size_t’
drivers/char/random.c: In function ‘account’:
drivers/char/random.c:859: warning: format ‘%d’ expects type ‘int’, but argument 5 has type ‘size_t’
drivers/char/random.c:881: warning: format ‘%d’ expects type ‘int’, but argument 5 has type ‘size_t’
drivers/char/random.c: In function ‘random_read’:
drivers/char/random.c:1141: warning: format ‘%d’ expects type ‘int’, but argument 5 has type ‘ssize_t’
drivers/char/random.c:1145: warning: format ‘%d’ expects type ‘int’, but argument 5 has type ‘ssize_t’
drivers/char/random.c:1145: warning: format ‘%d’ expects type ‘int’, but argument 6 has type ‘long unsigned int’

by using '%zd' instead of '%d' to properly denote ssize_t/size_t conversion.

Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Chet Kener <Cl3Kener@gmail.com>
random: prime last_data value per fips requirements

The value stored in last_data must be primed for FIPS 140-2 purposes. Upon
first use, either on system startup or after an RNDCLEARPOOL ioctl, we
need to take an initial random sample, store it internally in last_data,
then pass along the value after that to the requester, so that consistency
checks aren't being run against stale and possibly known data.

CC: Herbert Xu <herbert@gondor.apana.org.au>
CC: "David S. Miller" <davem@davemloft.net>
CC: Matt Mackall <mpm@selenic.com>
CC: linux-crypto@vger.kernel.org
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Chet Kener <Cl3Kener@gmail.com>
random: make it possible to enable debugging without rebuild

The module parameter that turns debugging mode (which basically means
printing a few extra lines during runtime) is in '#if 0' block. Forcing
everyone who would like to see how entropy is behaving on his system to
rebuild seems to be a little bit too harsh.

If we were concerned about speed, we could potentially turn 'debug' into a
static key, but I don't think it's necessary.

Drop the '#if 0' block to allow using the 'debug' parameter without rebuilding.

Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Chet Kener <Cl3Kener@gmail.com>
random: allow architectures to optionally define random_get_entropy()

Allow architectures which have a disabled get_cycles() function to
provide a random_get_entropy() function which provides a fine-grained,
rapidly changing counter that can be used by the /dev/random driver.

For example, an architecture might have a rapidly changing register
used to control random TLB cache eviction, or DRAM refresh that
doesn't meet the requirements of get_cycles(), but which is good
enough for the needs of the random driver.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@vger.kernel.org
Signed-off-by: Chet Kener <Cl3Kener@gmail.com>
random: statically compute poolbitshift, poolbytes, poolbits

Use a macro to statically compute poolbitshift (will be used in a
subsequent patch), poolbytes, and poolbits.  On virtually all
architectures the cost of a memory load with an offset is the same as
the one of a memory load.

It is still possible for this to generate worse code since the C
compiler doesn't know the fixed relationship between these fields, but
that is somewhat unlikely.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Chet Kener <Cl3Kener@gmail.com>
random: speed up the fast_mix function by a factor of four

By mixing the entropy in chunks of 32-bit words instead of byte by
byte, we can speed up the fast_mix function significantly.  Since it
is called on every single interrupt, on systems with a very heavy
interrupt load, this can make a noticeable difference.

Also fix a compilation warning in add_interrupt_randomness() and avoid
xor'ing cycles and jiffies together just in case we have an
architecture which tries to define random_get_entropy() by returning
jiffies.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reported-by: Jörn Engel <joern@logfs.org>
Signed-off-by: Chet Kener <Cl3Kener@gmail.com>
random: adjust the generator polynomials in the mixing function slightly

Our mixing functions were analyzed by Lacharme, Roeck, Strubel, and
Videau in their paper, "The Linux Pseudorandom Number Generator
Revisited" (see: http://eprint.iacr.org/2012/251.pdf).

They suggested a slight change to improve our mixing functions
slightly.  I also adjusted the comments to better explain what is
going on, and to document why the polynomials were changed.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Chet Kener <Cl3Kener@gmail.com>
random: make add_timer_randomness() fill the nonblocking pool first

Change add_timer_randomness() so that it directs incoming entropy to
the nonblocking pool first if it hasn't been fully initialized yet.
This matches the strategy we use in add_interrupt_randomness(), which
allows us to push the randomness where we need it the most during when
the system is first booting up, so that get_random_bytes() and
/dev/urandom become safe to use as soon as possible.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Chet Kener <Cl3Kener@gmail.com>
random: initialize the last_time field in struct timer_rand_state

Since we initialize jiffies to wrap five minutes before boot (see
INITIAL_JIFFIES defined in include/linux/jiffies.h) it's important to
make sure the last_time field is initialized to INITIAL_JIFFIES.
Otherwise, the entropy estimator will overestimate the amount of
entropy resulting from the first call to add_timer_randomness(),
generally by about 8 bits.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Chet Kener <Cl3Kener@gmail.com>
random: fix comment on proc_do_uuid

There's only one function here now, as uuid_strategy is long gone.
Also make the bit about "If accesses via ..." clearer.

Signed-off-by: Greg Price <price@mit.edu>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Chet Kener <Cl3Kener@gmail.com>
random: fix description of get_random_bytes

After this remark was written, commit d2e7c96af added a use of
arch_get_random_long() inside the get_random_bytes codepath.
The main point stands, but it needs to be reworded.

Signed-off-by: Greg Price <price@mit.edu>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Chet Kener <Cl3Kener@gmail.com>
random: fix comment on "account"

This comment didn't quite keep up as extract_entropy() was split into
four functions.  Put each bit by the function it describes.

Signed-off-by: Greg Price <price@mit.edu>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Chet Kener <Cl3Kener@gmail.com>
random: tighten bound on random_read_wakeup_thresh

We use this value in a few places other than its literal meaning,
in particular in _xfer_secondary_pool() as a minimum number of
bits to pull from the input pool at a time into either output
pool.  It doesn't make sense to pull more bits than the whole size
of an output pool.

We could and possibly should separate the quantities "how much
should the input pool have to have to wake up /dev/random readers"
and "how much should we transfer from the input to an output pool
at a time", but nobody is likely to be sad they can't set the first
quantity to more than 1024 bits, so for now just limit them both.

Signed-off-by: Greg Price <price@mit.edu>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Chet Kener <Cl3Kener@gmail.com>
msm: Improve qpnp-vibrator scheduling

 * Skip the workqueue and use spinlocks to improve interactivity
 * This vastly improves "recent apps" in Android

Change-Id: I77da17b4f1ce2f213772c41ddbac21250432279e
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
Signed-off-by: Chet Kener <Cl3Kener@gmail.com>