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authorMauro Carvalho Chehab <mchehab+samsung@kernel.org>2019-06-27 20:56:51 +0300
committerMauro Carvalho Chehab <mchehab+samsung@kernel.org>2019-07-15 17:03:02 +0300
commit4f4cfa6c560c93ba180c30675cf845e1597de44c (patch)
tree0bbe2ec9e6ef62ed2a347504dda50c6bdbe43703 /Documentation/hw_random.txt
parentda82c92f1150f66afabf78d2c85ef9ac18dc6d38 (diff)
downloadlinux-4f4cfa6c560c93ba180c30675cf845e1597de44c.tar.xz
docs: admin-guide: add a series of orphaned documents
There are lots of documents that belong to the admin-guide but are on random places (most under Documentation root dir). Move them to the admin guide. Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Acked-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
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-==========================================================
-Linux support for random number generator in i8xx chipsets
-==========================================================
-
-Introduction
-============
-
-The hw_random framework is software that makes use of a
-special hardware feature on your CPU or motherboard,
-a Random Number Generator (RNG). The software has two parts:
-a core providing the /dev/hwrng character device and its
-sysfs support, plus a hardware-specific driver that plugs
-into that core.
-
-To make the most effective use of these mechanisms, 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/
-
-Those tools use /dev/hwrng to fill the kernel entropy pool,
-which is used internally and exported by the /dev/urandom and
-/dev/random special files.
-
-Theory of operation
-===================
-
-CHARACTER DEVICE. 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.
-
-The rng-tools package uses such tests in "rngd", and lets you
-run them by hand with a "rngtest" utility.
-
-/dev/hwrng is char device major 10, minor 183.
-
-CLASS DEVICE. There is a /sys/class/misc/hw_random node with
-two unique attributes, "rng_available" and "rng_current". The
-"rng_available" attribute lists the hardware-specific drivers
-available, while "rng_current" lists the one which is currently
-connected to /dev/hwrng. If your system has more than one
-RNG available, you may change the one used by writing a name from
-the list in "rng_available" into "rng_current".
-
-==========================================================================
-
-
-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>
-
-
-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.
-
-Intel RNG Driver notes
-======================
-
-FIXME: support poll(2)
-
-.. note::
-
- request_mem_region was removed, for three 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.