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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 aspecial hardware feature on your CPU or motherboard,a Random Number Generator (RNG).In order to make effective use of this device driver, youshould download the support software as well. Download thelatest version of the "rng-tools" package from thehw_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 quantummechanical properties of silicon. When not generating new randombits the RNG circuitry will enter a low power state. Intel willprovide a binary software driver to give third party softwareaccess 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 fromthe hardware RNG device. This data is NOT CHECKED by anyfitness tests, and could potentially be bogus (if thehardware is faulty or has been tampered with). Data is onlyoutput if the hardware "has-data" flag is set, but neverthelessa security-conscious person would run fitness tests on thedata 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 locationused by the RNG is a fixed location in MMIO-addressable memory,3) users with properly working BIOS e820 handling will alwayshave the region in which the RNG is located reserved, sorequest_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) cansucceed.Driver details:Based on:Intel 82802AB/82802AC Firmware Hub (FWH) DatasheetMay 1999 Order Number: 290658-002 RIntel 82802 Firmware Hub: Random Number GeneratorProgrammer's Reference ManualDecember 1999 Order Number: 298029-001 RIntel 82802 Firmware HUB Random Number Generator DriverCopyright (c) 2000 Matt Sottek <msottek@quiknet.com>Special thanks to Matt Sottek. I did the "guts", hedid the "brains" and all the testing.
