mirror of
https://github.com/team-infusion-developers/android_kernel_samsung_msm8976.git
synced 2024-11-05 18:59:58 +00:00
1da177e4c3
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
69 lines
2.6 KiB
Text
69 lines
2.6 KiB
Text
Hardware driver for Intel/AMD/VIA Random Number Generators (RNG)
|
|
Copyright 2000,2001 Jeff Garzik <jgarzik@pobox.com>
|
|
Copyright 2000,2001 Philipp Rumpf <prumpf@mandrakesoft.com>
|
|
|
|
Introduction:
|
|
|
|
The hw_random device driver is software that makes use of a
|
|
special hardware feature on your CPU or motherboard,
|
|
a Random Number Generator (RNG).
|
|
|
|
In order to make effective use of this device driver, you
|
|
should download the support software as well. Download the
|
|
latest version of the "rng-tools" package from the
|
|
hw_random driver's official Web site:
|
|
|
|
http://sourceforge.net/projects/gkernel/
|
|
|
|
About the Intel RNG hardware, from the firmware hub datasheet:
|
|
|
|
The Firmware Hub integrates a Random Number Generator (RNG)
|
|
using thermal noise generated from inherently random quantum
|
|
mechanical properties of silicon. When not generating new random
|
|
bits the RNG circuitry will enter a low power state. Intel will
|
|
provide a binary software driver to give third party software
|
|
access to our RNG for use as a security feature. At this time,
|
|
the RNG is only to be used with a system in an OS-present state.
|
|
|
|
Theory of operation:
|
|
|
|
Character driver. Using the standard open()
|
|
and read() system calls, you can read random data from
|
|
the hardware RNG device. This data is NOT CHECKED by any
|
|
fitness tests, and could potentially be bogus (if the
|
|
hardware is faulty or has been tampered with). Data is only
|
|
output if the hardware "has-data" flag is set, but nevertheless
|
|
a security-conscious person would run fitness tests on the
|
|
data before assuming it is truly random.
|
|
|
|
/dev/hwrandom is char device major 10, minor 183.
|
|
|
|
Driver notes:
|
|
|
|
* FIXME: support poll(2)
|
|
|
|
NOTE: request_mem_region was removed, for two reasons:
|
|
1) Only one RNG is supported by this driver, 2) The location
|
|
used by the RNG is a fixed location in MMIO-addressable memory,
|
|
3) users with properly working BIOS e820 handling will always
|
|
have the region in which the RNG is located reserved, so
|
|
request_mem_region calls always fail for proper setups.
|
|
However, for people who use mem=XX, BIOS e820 information is
|
|
-not- in /proc/iomem, and request_mem_region(RNG_ADDR) can
|
|
succeed.
|
|
|
|
Driver details:
|
|
|
|
Based on:
|
|
Intel 82802AB/82802AC Firmware Hub (FWH) Datasheet
|
|
May 1999 Order Number: 290658-002 R
|
|
|
|
Intel 82802 Firmware Hub: Random Number Generator
|
|
Programmer's Reference Manual
|
|
December 1999 Order Number: 298029-001 R
|
|
|
|
Intel 82802 Firmware HUB Random Number Generator Driver
|
|
Copyright (c) 2000 Matt Sottek <msottek@quiknet.com>
|
|
|
|
Special thanks to Matt Sottek. I did the "guts", he
|
|
did the "brains" and all the testing.
|