Using x86 RDRAND instruction, two functions are supplied to
generate a 32bit or 64bit number.
One potential usage is the sealing key generation for SGX.
BUG=chrome-os-partner:62438
BRANCH=NONE
TEST=Tested on Eve to generate a 64bit random number.
Change-Id: I50cbeda4de17ccf2fc5efc1fe04f6b1a31ec268c
Signed-off-by: Robbie Zhang <robbie.zhang@intel.com>
Reviewed-on: https://review.coreboot.org/18362
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
