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| author | Tony Luck <tony.luck@intel.com> | 2012-07-23 20:47:57 +0400 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2012-09-12 06:37:30 +0400 |
| commit | 86946487268d34e8c057e498ab01b03cc085874f (patch) | |
| tree | 55194e49d8bac37b4a47625de0fe8b3e4dc01c5f /drivers/char | |
| parent | 946887406e6d559a4a52fdbd836a85511b4f6486 (diff) | |
| download | linux-86946487268d34e8c057e498ab01b03cc085874f.tar.xz | |
random: Add comment to random_initialize()
commit cbc96b7594b5691d61eba2db8b2ea723645be9ca upstream.
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>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'drivers/char')
| -rw-r--r-- | drivers/char/random.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c index 918979fb4131..8ae923573781 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -1114,6 +1114,16 @@ 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); |