| From 49d6f03641b2f46b9077aa68500ef599157c228d Mon Sep 17 00:00:00 2001 |
| From: Tony Luck <tony.luck@intel.com> |
| Date: Mon, 23 Jul 2012 09:47:57 -0700 |
| Subject: [PATCH] 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> |
| |
| diff --git a/drivers/char/random.c b/drivers/char/random.c |
| index ee3d6d0..69eaacd 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); |
| -- |
| 1.7.12.rc1.1.gbce1580 |
| |
