diff options
author | Tony Luck <tony.luck@intel.com> | 2012-07-23 09:47:57 -0700 |
---|---|---|
committer | Paul Gortmaker <paul.gortmaker@windriver.com> | 2012-08-17 15:36:09 -0400 |
commit | aed22e34348fd7914fafcd9d35c58de486ce7a0a (patch) | |
tree | 01143da1bf051639d42133bf5f5e3f8dc0fef212 | |
parent | b1e34220df49a66f2bdd52eb2326252e819eefe1 (diff) |
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: Paul Gortmaker <paul.gortmaker@windriver.com>
-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 1644b8e6ee6b..7e194064c5fd 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -1088,6 +1088,16 @@ 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); |