Commit cbc96b75 authored Jul 23, 2012 by Tony Luck Committed by Theodore Ts'o Jul 24, 2012

random: Add comment to random_initialize()



Many platforms have per-machine instance data (serial numbers,
asset tags, etc.) squirreled away in areas that are accessed
during early system bringup. Mixing this data into the random
pools has a very high value in providing better random data,
so we should allow (and even encourage) architecture code to
call add_device_randomness() from the setup_arch() paths.

However, this limits our options for internal structure of
the random driver since random_initialize() is not called
until long after setup_arch().

Add a big fat comment to rand_initialize() spelling out
this requirement.

Suggested-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

parent b4237003

drivers/char/random.c

+10 −0

Original line number	Diff line number	Diff line
		@@ -1087,6 +1087,16 @@ static void init_std_data(struct entropy_store *r)
		mix_pool_bytes(r, utsname(), sizeof(*(utsname())), NULL);
		}

		/*
		* Note that setup_arch() may call add_device_randomness()
		* long before we get here. This allows seeding of the pools
		* with some platform dependent data very early in the boot
		* process. But it limits our options here. We must use
		* statically allocated structures that already have all
		* initializations complete at compile time. We should also
		* take care not to overwrite the precious per platform data
		* we were given.
		*/
		static int rand_initialize(void)
		{
		init_std_data(&input_pool);