x86, random: Verify RDRAND functionality and allow it to be disabled
authorH. Peter Anvin <hpa@zytor.com>
Sun, 31 Jul 2011 21:02:19 +0000 (14:02 -0700)
committerH. Peter Anvin <hpa@zytor.com>
Sun, 31 Jul 2011 21:02:19 +0000 (14:02 -0700)
commit49d859d78c5aeb998b6936fcb5f288f78d713489
tree04b7746d1b79ab12bf94ff1eaf9ab91e74db37ef
parent628c6246d47b85f5357298601df2444d7f4dd3fd
x86, random: Verify RDRAND functionality and allow it to be disabled

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>
Documentation/kernel-parameters.txt
arch/x86/include/asm/archrandom.h
arch/x86/kernel/cpu/Makefile
arch/x86/kernel/cpu/common.c
arch/x86/kernel/cpu/rdrand.c [new file with mode: 0644]