user/sven/linux.git/include/linux/hw_random.h, branch v4.14.328

random: pull add_hwgenerator_randomness() declaration into random.h

2022-06-25T09:46:35Z

commit b777c38239fec5a528e59f55b379e31b1a187524 upstream. add_hwgenerator_randomness() is a function implemented and documented inside of random.c. It is the way that hardware RNGs push data into it. Therefore, it should be declared in random.h. Otherwise sparse complains with: random.c:1137:6: warning: symbol 'add_hwgenerator_randomness' was not declared. Should it be static? The alternative would be to include hw_random.h into random.c, but that wouldn't really be good for anything except slowing down compile time. Cc: Matt Mackall Cc: Theodore Ts'o Acked-by: Herbert Xu Reviewed-by: Eric Biggers Reviewed-by: Dominik Brodowski Signed-off-by: Jason A. Donenfeld Signed-off-by: Greg Kroah-Hartman

random: use hash function for crng_slow_load()

2022-06-25T09:46:33Z

commit 66e4c2b9541503d721e936cc3898c9f25f4591ff upstream. Since we have a hash function that's really fast, and the goal of crng_slow_load() is reportedly to "touch all of the crng's state", we can just hash the old state together with the new state and call it a day. This way we dont need to reason about another LFSR or worry about various attacks there. This code is only ever used at early boot and then never again. Cc: Theodore Ts'o Reviewed-by: Dominik Brodowski Reviewed-by: Eric Biggers Signed-off-by: Jason A. Donenfeld Signed-off-by: Greg Kroah-Hartman

hwrng: Make explicit that max >= 32 always

2016-11-21T14:50:45Z

As hw_random core calls ->read with max > 32 or more, make it explicit. Also remove checks involving 'max' being less than 8. Signed-off-by: PrasannaKumar Muralidharan Signed-off-by: Herbert Xu

hwrng: core - Improve description of the ->read() interface

2016-08-24T13:04:48Z

Currently, very few RNG drivers support single byte reads using the ->read() interface. Of the 14 drivers in drivers/char/hw_random that support this interface only three of these actually support max == 1. The other behaviours vary between return 0, return 2, return 4 and return -EIO). This is not a problem in practice because the core hw_random code never performs a read shorter than 16 bytes. The documentation for this function already contrains the alignment of the buffer pointer, so let's also guarantee that the buffer is at least as large as its alignment. This constraint is intended to be the weakest guarantee neccessary to allow driver writers to safely simplify their code. Signed-off-by: Daniel Thompson Signed-off-by: Herbert Xu

hwrng: add devm_* interfaces

2015-03-16T10:45:54Z

This change adds devm_hwrng_register and devm_hwrng_unregister which use can simplify error unwinding and unbinding code paths in device drivers. Signed-off-by: Dmitry Torokhov Signed-off-by: Herbert Xu

hwrng: core - Use struct completion for cleanup_done

2014-12-25T21:33:34Z

There is no point in doing a manual completion for cleanup_done when struct completion fits in perfectly. Signed-off-by: Herbert Xu

hwrng: fix unregister race.

2014-12-22T12:02:40Z

The previous patch added one potential problem: we can still be reading from a hwrng when it's unregistered. Add a wait for zero in the hwrng_unregister path. Signed-off-by: Rusty Russell Signed-off-by: Amos Kong Signed-off-by: Herbert Xu

hwrng: use reference counts on each struct hwrng.

2014-12-22T12:02:39Z

current_rng holds one reference, and we bump it every time we want to do a read from it. This means we only hold the rng_mutex to grab or drop a reference, so accessing /sys/devices/virtual/misc/hw_random/rng_current doesn't block on read of /dev/hwrng. Using a kref is overkill (we're always under the rng_mutex), but a standard pattern. This also solves the problem that the hwrng_fillfn thread was accessing current_rng without a lock, which could change (eg. to NULL) underneath it. Signed-off-by: Rusty Russell Signed-off-by: Amos Kong Signed-off-by: Herbert Xu

hwrng: add per-device entropy derating

2014-07-15T08:49:40Z

This patch introduces a derating factor to struct hwrng for the random bits going into the kernel input pool, and a common default derating for drivers which do not specify one. Signed-off-by: Torsten Duwe Signed-off-by: Theodore Ts'o Acked-by: H. Peter Anvin

random: add_hwgenerator_randomness() for feeding entropy from devices

2014-07-15T08:49:40Z

This patch adds an interface to the random pool for feeding entropy in-kernel. Signed-off-by: Torsten Duwe Signed-off-by: Theodore Ts'o Acked-by: H. Peter Anvin