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authorH. Peter Anvin <hpa@zytor.com>2011-07-31 14:02:19 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-10-21 09:17:12 -0700
commit8b9b3bf4e79b8f41fa910932885526c2d1083af9 (patch)
tree13ccd050915a838b801c99aaf5a06a4a6c89bdc6 /Documentation
parent5faf9fc361bac926a2f9efe6018fdc16c0e7dad8 (diff)
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x86, random: Verify RDRAND functionality and allow it to be disabled
commit 49d859d78c5aeb998b6936fcb5f288f78d713489 upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/kernel-parameters.txt5
1 files changed, 5 insertions, 0 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index aa47be7..397ee05 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1764,6 +1764,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
noresidual [PPC] Don't use residual data on PReP machines.
+ nordrand [X86] Disable the direct use of the RDRAND
+ instruction even if it is supported by the
+ processor. RDRAND is still available to user
+ space applications.
+
noresume [SWSUSP] Disables resume and restores original swap
space.