linux-toradex.git/drivers/char/random.c, branch v5.17

random: only call crng_finalize_init() for primary_crng

2022-02-04T18:22:32+00:00

crng_finalize_init() returns instantly if it is called for another pool
than primary_crng. The test whether crng_finalize_init() is still required
can be moved to the relevant caller in crng_reseed(), and
crng_need_final_init can be reset to false if crng_finalize_init() is
called with workqueues ready. Then, no previous callsite will call
crng_finalize_init() unless it is needed, and we can get rid of the
superfluous function parameter.

Signed-off-by: Dominik Brodowski 
Signed-off-by: Jason A. Donenfeld

random: access primary_pool directly rather than through pointer

2022-02-04T18:22:32+00:00

Both crng_initialize_primary() and crng_init_try_arch_early() are
only called for the primary_pool. Accessing it directly instead of
through a function parameter simplifies the code.

Signed-off-by: Dominik Brodowski 
Signed-off-by: Jason A. Donenfeld

random: wake up /dev/random writers after zap

2022-02-04T18:22:32+00:00

When account() is called, and the amount of entropy dips below
random_write_wakeup_bits, we wake up the random writers, so that they
can write some more in. However, the RNDZAPENTCNT/RNDCLEARPOOL ioctl
sets the entropy count to zero -- a potential reduction just like
account() -- but does not unblock writers. This commit adds the missing
logic to that ioctl to unblock waiting writers.

Reviewed-by: Dominik Brodowski 
Signed-off-by: Jason A. Donenfeld

random: continually use hwgenerator randomness

2022-02-04T18:22:32+00:00

The rngd kernel thread may sleep indefinitely if the entropy count is
kept above random_write_wakeup_bits by other entropy sources. To make
best use of multiple sources of randomness, mix entropy from hardware
RNGs into the pool at least once within CRNG_RESEED_INTERVAL.

Cc: Herbert Xu 
Cc: Jason A. Donenfeld 
Signed-off-by: Dominik Brodowski 
Signed-off-by: Jason A. Donenfeld

random: move the random sysctl declarations to its own file

2022-01-22T06:33:35+00:00

kernel/sysctl.c is a kitchen sink where everyone leaves their dirty
dishes, this makes it very difficult to maintain.

To help with this maintenance let's start by moving sysctls to places
where they actually belong.  The proc sysctl maintainers do not want to
know what sysctl knobs you wish to add for your own piece of code, we
just care about the core logic.

So move the random sysctls to their own file and use
register_sysctl_init().

[mcgrof@kernel.org: commit log update to justify the move]

Link: https://lkml.kernel.org/r/20211124231435.1445213-3-mcgrof@kernel.org
Signed-off-by: Xiaoming Ni 
Signed-off-by: Luis Chamberlain 
Cc: Al Viro 
Cc: Amir Goldstein 
Cc: Andy Shevchenko 
Cc: Antti Palosaari 
Cc: Arnd Bergmann 
Cc: Benjamin Herrenschmidt 
Cc: Benjamin LaHaise 
Cc: Clemens Ladisch 
Cc: David Airlie 
Cc: Douglas Gilbert 
Cc: Eric Biederman 
Cc: Greg Kroah-Hartman 
Cc: Iurii Zaikin 
Cc: James E.J. Bottomley 
Cc: Jani Nikula 
Cc: Jani Nikula 
Cc: Jan Kara 
Cc: Joel Becker 
Cc: John Ogness 
Cc: Joonas Lahtinen 
Cc: Joseph Qi 
Cc: Julia Lawall 
Cc: Kees Cook 
Cc: Lukas Middendorf 
Cc: Mark Fasheh 
Cc: Martin K. Petersen 
Cc: Paul Turner 
Cc: Peter Zijlstra 
Cc: Petr Mladek 
Cc: Phillip Potter 
Cc: Qing Wang 
Cc: "Rafael J. Wysocki" 
Cc: Rodrigo Vivi 
Cc: Sebastian Reichel 
Cc: Sergey Senozhatsky 
Cc: Stephen Kitt 
Cc: Steven Rostedt (VMware) 
Cc: Suren Baghdasaryan 
Cc: Tetsuo Handa 
Cc: "Theodore Ts'o" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

random: simplify arithmetic function flow in account()

2022-01-18T12:03:56+00:00

Now that have_bytes is never modified, we can simplify this function.
First, we move the check for negative entropy_count to be first. That
ensures that subsequent reads of this will be non-negative. Then,
have_bytes and ibytes can be folded into their one use site in the
min_t() function.

Suggested-by: Dominik Brodowski 
Reviewed-by: Dominik Brodowski 
Signed-off-by: Jason A. Donenfeld

random: selectively clang-format where it makes sense

2022-01-18T12:03:56+00:00

This is an old driver that has seen a lot of different eras of kernel
coding style. In an effort to make it easier to code for, unify the
coding style around the current norm, by accepting some of -- but
certainly not all of -- the suggestions from clang-format. This should
remove ambiguity in coding style, especially with regards to spacing,
when code is being changed or amended. Consequently it also makes code
review easier on the eyes, following one uniform style rather than
several.

Reviewed-by: Dominik Brodowski 
Signed-off-by: Jason A. Donenfeld

random: access input_pool_data directly rather than through pointer

2022-01-18T12:03:56+00:00

This gets rid of another abstraction we no longer need. It would be nice
if we could instead make pool an array rather than a pointer, but the
latent entropy plugin won't be able to do its magic in that case. So
instead we put all accesses to the input pool's actual data through the
input_pool_data array directly.

Reviewed-by: Dominik Brodowski 
Signed-off-by: Jason A. Donenfeld

random: cleanup fractional entropy shift constants

2022-01-18T12:03:56+00:00

The entropy estimator is calculated in terms of 1/8 bits, which means
there are various constants where things are shifted by 3. Move these
into our pool info enum with the other relevant constants. While we're
at it, move an English assertion about sizes into a proper BUILD_BUG_ON
so that the compiler can ensure this invariant.

Reviewed-by: Dominik Brodowski 
Signed-off-by: Jason A. Donenfeld

random: prepend remaining pool constants with POOL_

2022-01-18T12:03:56+00:00

The other pool constants are prepended with POOL_, but not these last
ones. Rename them. This will then let us move them into the enum in the
following commit.

Reviewed-by: Dominik Brodowski 
Signed-off-by: Jason A. Donenfeld