linux-toradex.git/arch/x86/kernel/cpu/rdrand.c, branch v3.2 Linux kernel for Apalis and Colibri modules x86, random: Verify RDRAND functionality and allow it to be disabled 2011-07-31T21:02:19+00:00 H. Peter Anvin hpa@zytor.com 2011-07-31T21:02:19+00:00 49d859d78c5aeb998b6936fcb5f288f78d713489 If the CPU declares that RDRAND is available, go through a guranteed reseed sequence, and make sure that it is actually working (producing data.) If it does not, disable the CPU feature flag. Allow RDRAND to be disabled on the command line (as opposed to at compile time) for a user who has special requirements with regards to random numbers. Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Cc: Matt Mackall <mpm@selenic.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: "Theodore Ts'o" <tytso@mit.edu> 
If the CPU declares that RDRAND is available, go through a guranteed
reseed sequence, and make sure that it is actually working (producing
data.)   If it does not, disable the CPU feature flag.

Allow RDRAND to be disabled on the command line (as opposed to at
compile time) for a user who has special requirements with regards to
random numbers.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: Matt Mackall <mpm@selenic.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "Theodore Ts'o" <tytso@mit.edu>