linux/arch/x86
H. Peter Anvin 628c6246d4 x86, random: Architectural inlines to get random integers with RDRAND
Architectural inlines to get random ints and longs using the RDRAND
instruction.

Intel has introduced a new RDRAND instruction, a Digital Random Number
Generator (DRNG), which is functionally an high bandwidth entropy
source, cryptographic whitener, and integrity monitor all built into
hardware.  This enables RDRAND to be used directly, bypassing the
kernel random number pool.

For technical documentation, see:

http://software.intel.com/en-us/articles/download-the-latest-bull-mountain-software-implementation-guide/

In this patch, this is *only* used for the nonblocking random number
pool.  RDRAND is a nonblocking source, similar to our /dev/urandom,
and is therefore not a direct replacement for /dev/random.  The
architectural hooks presented in the previous patch only feed the
kernel internal users, which only use the nonblocking pool, and so
this is not a problem.

Since this instruction is available in userspace, there is no reason
to have a /dev/hw_rng device driver for the purpose of feeding rngd.
This is especially so since RDRAND is a nonblocking source, and needs
additional whitening and reduction (see the above technical
documentation for details) in order to be of "pure entropy source"
quality.

The CONFIG_EXPERT compile-time option can be used to disable this use
of RDRAND.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Originally-by: Fenghua Yu <fenghua.yu@intel.com>
Cc: Matt Mackall <mpm@selenic.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "Theodore Ts'o" <tytso@mit.edu>
2011-07-31 13:59:29 -07:00
..
boot x86, setup: When probing memory with e801, use ax/bx as a pair 2011-04-25 14:52:37 -07:00
configs cgroup: remove the ns_cgroup 2011-05-26 17:12:34 -07:00
crypto crypto: aesni-intel - fix aesni build on i386 2011-05-18 09:03:34 +10:00
ia32 ns: Wire up the setns system call 2011-05-28 10:48:39 -07:00
include/asm x86, random: Architectural inlines to get random integers with RDRAND 2011-07-31 13:59:29 -07:00
kernel x86: Make Dell Latitude E6420 use reboot=pci 2011-07-21 11:47:17 -07:00
kvm KVM: x86 emulator: fix %rip-relative addressing with immediate source operand 2011-06-29 10:09:25 +03:00
lguest lguest: fix timer interrupt setup 2011-05-30 11:14:10 +09:30
lib Merge branches 'x86-apic-for-linus', 'x86-asm-for-linus' and 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2011-05-19 17:49:35 -07:00
math-emu
mm mm: Move definition of MIN_MEMORY_BLOCK_SIZE to a header 2011-07-12 11:08:01 +10:00
net net: filter: Just In Time compiler for x86-64 2011-04-27 23:05:08 -07:00
oprofile oprofile, x86: Fix race in nmi handler while starting counters 2011-06-15 14:31:29 +02:00
pci Merge branch 'stable/bug.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen 2011-07-07 13:19:04 -07:00
platform x86: Don't use the EFI reboot method by default 2011-07-07 11:35:05 +02:00
power
tools
vdso x86: vdso: Remove unused variable 2011-05-26 13:17:35 +02:00
video
xen xen/mmu: Fix for linker errors when CONFIG_SMP is not defined. 2011-06-30 09:21:10 -04:00
.gitignore
Kbuild net: filter: Just In Time compiler for x86-64 2011-04-27 23:05:08 -07:00
Kconfig x86, random: Architectural inlines to get random integers with RDRAND 2011-07-31 13:59:29 -07:00
Kconfig.cpu x86, cpu: Move AMD Elan Kconfig under "Processor family" 2011-04-08 13:01:25 -07:00
Kconfig.debug lib: consolidate DEBUG_STACK_USAGE option 2011-05-25 08:39:54 -07:00
Makefile Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-10-21 13:06:00 -07:00
Makefile_32.cpu x86, cpu: Move AMD Elan Kconfig under "Processor family" 2011-04-08 13:01:25 -07:00