^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1) ==========================================================
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2) Linux support for random number generator in i8xx chipsets
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3) ==========================================================
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5) Introduction
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6) ============
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 8) The hw_random framework is software that makes use of a
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 9) special hardware feature on your CPU or motherboard,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) a Random Number Generator (RNG). The software has two parts:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) a core providing the /dev/hwrng character device and its
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) sysfs support, plus a hardware-specific driver that plugs
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) into that core.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) To make the most effective use of these mechanisms, you
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) should download the support software as well. Download the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) latest version of the "rng-tools" package from the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) hw_random driver's official Web site:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) http://sourceforge.net/projects/gkernel/
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) Those tools use /dev/hwrng to fill the kernel entropy pool,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) which is used internally and exported by the /dev/urandom and
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) /dev/random special files.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) Theory of operation
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) ===================
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) CHARACTER DEVICE. Using the standard open()
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) and read() system calls, you can read random data from
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) the hardware RNG device. This data is NOT CHECKED by any
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) fitness tests, and could potentially be bogus (if the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) hardware is faulty or has been tampered with). Data is only
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) output if the hardware "has-data" flag is set, but nevertheless
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) a security-conscious person would run fitness tests on the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) data before assuming it is truly random.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) The rng-tools package uses such tests in "rngd", and lets you
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) run them by hand with a "rngtest" utility.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) /dev/hwrng is char device major 10, minor 183.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) CLASS DEVICE. There is a /sys/class/misc/hw_random node with
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) two unique attributes, "rng_available" and "rng_current". The
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) "rng_available" attribute lists the hardware-specific drivers
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) available, while "rng_current" lists the one which is currently
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) connected to /dev/hwrng. If your system has more than one
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) RNG available, you may change the one used by writing a name from
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) the list in "rng_available" into "rng_current".
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) ==========================================================================
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) Hardware driver for Intel/AMD/VIA Random Number Generators (RNG)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) - Copyright 2000,2001 Jeff Garzik <jgarzik@pobox.com>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) - Copyright 2000,2001 Philipp Rumpf <prumpf@mandrakesoft.com>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) About the Intel RNG hardware, from the firmware hub datasheet
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) =============================================================
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) The Firmware Hub integrates a Random Number Generator (RNG)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) using thermal noise generated from inherently random quantum
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64) mechanical properties of silicon. When not generating new random
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) bits the RNG circuitry will enter a low power state. Intel will
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) provide a binary software driver to give third party software
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) access to our RNG for use as a security feature. At this time,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68) the RNG is only to be used with a system in an OS-present state.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) Intel RNG Driver notes
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71) ======================
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73) FIXME: support poll(2)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75) .. note::
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77) request_mem_region was removed, for three reasons:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79) 1) Only one RNG is supported by this driver;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80) 2) The location used by the RNG is a fixed location in
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81) MMIO-addressable memory;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82) 3) users with properly working BIOS e820 handling will always
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83) have the region in which the RNG is located reserved, so
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84) request_mem_region calls always fail for proper setups.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85) However, for people who use mem=XX, BIOS e820 information is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86) **not** in /proc/iomem, and request_mem_region(RNG_ADDR) can
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 87) succeed.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 88)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 89) Driver details
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 90) ==============
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 91)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 92) Based on:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 93) Intel 82802AB/82802AC Firmware Hub (FWH) Datasheet
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 94) May 1999 Order Number: 290658-002 R
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 95)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 96) Intel 82802 Firmware Hub:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 97) Random Number Generator
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 98) Programmer's Reference Manual
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 99) December 1999 Order Number: 298029-001 R
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) Intel 82802 Firmware HUB Random Number Generator Driver
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) Copyright (c) 2000 Matt Sottek <msottek@quiknet.com>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) Special thanks to Matt Sottek. I did the "guts", he
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) did the "brains" and all the testing.
Orange Pi5 kernel
Deprecated Linux kernel 5.10.110 for OrangePi 5/5B/5+ boards
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