core: rng_hw: Remove __weak attribute from HW RNG functions

These function are no longer overridden by platform HW RNG drivers.
Drivers only need implement hw_get_random_bytes().

Signed-off-by: And

core: rng_hw: Remove __weak attribute from HW RNG functions

These function are no longer overridden by platform HW RNG drivers.
Drivers only need implement hw_get_random_bytes().

Signed-off-by: Andrew Davis <afd@ti.com>
Reviewed-by: Jerome Forissier <jerome.forissier@linaro.org>
Reviewed-by: Jens Wiklander <jens.wiklander@linaro.org>
Reviewed-by: Etienne Carriere <etienne.carriere@linaro.org>

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core: rng_hw: Remove hw_get_random_byte()

Now that all everyone is moved over to hw_get_random_bytes()
we can remove the stub hw_get_random_byte() and the weak default
hw_get_random_bytes().

Signed

core: rng_hw: Remove hw_get_random_byte()

Now that all everyone is moved over to hw_get_random_bytes()
we can remove the stub hw_get_random_byte() and the weak default
hw_get_random_bytes().

Signed-off-by: Andrew Davis <afd@ti.com>
Reviewed-by: Jerome Forissier <jerome.forissier@linaro.org>
Reviewed-by: Jens Wiklander <jens.wiklander@linaro.org>
Reviewed-by: Etienne Carriere <etienne.carriere@linaro.org>

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core: rng_hw: Add dummy hw_get_random_byte()

This is only used so we can start removing hw_get_random_byte() from
platforms without causing compile errors. It is never called.

Signed-off-by: Andrew

core: rng_hw: Add dummy hw_get_random_byte()

This is only used so we can start removing hw_get_random_byte() from
platforms without causing compile errors. It is never called.

Signed-off-by: Andrew Davis <afd@ti.com>
Reviewed-by: Etienne Carriere <etienne.carriere@linaro.org>
Reviewed-by: Jens Wiklander <jens.wiklander@linaro.org>

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core: Add hw_get_random_bytes()

Currently there are two options for supporting hardware RNG, implementing
hw_get_random_byte() or overriding crypto_rng_read().

crypto_rng_read() is provided by eith

core: Add hw_get_random_bytes()

Currently there are two options for supporting hardware RNG, implementing
hw_get_random_byte() or overriding crypto_rng_read().

crypto_rng_read() is provided by either a software PRNG or by a hardware
RNG through a weak function in rng_hw.c. This weak function repeatedly
calls hw_get_random_byte(). This can be an unneeded slowdown for
platforms that fetch more than one byte of randomness per call to their
HW RNG (all of them). The usual pattern is to store these extra bytes
in a FIFO and feed them out one at a time. But since the only two callers
of hw_get_random_byte() are themselves users of more than one byte this
indirection is unnecessary. To get around this some platforms have also
started overriding crypto_rng_read() which makes the API flow a bit less
intuitive than it could be.

Plan here is that platforms only need to implement hw_get_random_bytes().
This can be called with length = 1 if we only need a single byte. But in
the more common case we get a performance boost and simplify the RNG call
flow.

To start we keep hw_get_random_byte() and have the new
hw_get_random_bytes() use it to get platform HW RNG byte at a time.
When we finish moving all plats over to hw_get_random_bytes() then
hw_get_random_byte() can be removed.

Signed-off-by: Andrew Davis <afd@ti.com>
Reviewed-by: Etienne Carriere <etienne.carriere@linaro.org>
Reviewed-by: Jens Wiklander <jens.wiklander@linaro.org>

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Remove get_rng_array()

Removes get_rng_array() in favor of crypto_rng_read() which always uses
the configured RNG implementation to draw random.

Reviewed-by: Jerome Forissier <jerome.forissier@lina

Remove get_rng_array()

Removes get_rng_array() in favor of crypto_rng_read() which always uses
the configured RNG implementation to draw random.

Reviewed-by: Jerome Forissier <jerome.forissier@linaro.org>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>

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core: add new RNG implementation

Adds a new cryptographically secure pseudo random number generator known
as Fortuna. The implementation is based on the description in [0]. This
implementation repla

core: add new RNG implementation

Adds a new cryptographically secure pseudo random number generator known
as Fortuna. The implementation is based on the description in [0]. This
implementation replaces the implementation in LTC which was used until
now.

Gathering of entropy has been refined with crypto_rng_add_event() to
better match how entropy is added to Fortuna. A enum crypto_rng_src
identifies the source of the event. The source also controls how the
event is added. There are two options available, queue it in a circular
buffer for later processing or adding it directly to a pool. The former
option is suitable when being called from an interrupt handler or some
other place where RPC to normal world is forbidden.

plat_prng_add_jitter_entropy_norpc() is removed and
plat_prng_add_jitter_entropy() is updated to use this new entropy source
scheme.

The configuration of LTC is simplified by this, now PRNG is always drawn
via prng_mpa_desc.

plat_rng_init() takes care of initializing the PRNG in order to allow
platforms to override or enhance the Fortuna integration.

[0] Link:https://www.schneier.com/academic/paperfiles/fortuna.pdf

Reviewed-by: Jerome Forissier <jerome.forissier@linaro.org>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>

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