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author | Tony Luck <tony.luck@intel.com> | 2012-07-23 09:47:57 -0700 |
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committer | Theodore Ts'o <tytso@mit.edu> | 2012-07-24 13:16:41 -0400 |
commit | cbc96b7594b5691d61eba2db8b2ea723645be9ca (patch) | |
tree | 440e0d132abdb6b1d03e9440c803c0f7e2db38fc /drivers/char/random.c | |
parent | b4237003cff66084ebeb502412d9cee392e6f52f (diff) | |
download | op-kernel-dev-cbc96b7594b5691d61eba2db8b2ea723645be9ca.zip op-kernel-dev-cbc96b7594b5691d61eba2db8b2ea723645be9ca.tar.gz |
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>
Diffstat (limited to 'drivers/char/random.c')
-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 9793b40..1a2dfa8 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -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); |