patch-2.4.23 linux-2.4.23/Documentation/hw_random.txt

• Lines: 139
• Date: 2003-11-28 10:26:19.000000000 -0800
• Orig file: linux-2.4.22/Documentation/hw_random.txt
• Orig date: 1969-12-31 16:00:00.000000000 -0800

diff -urN linux-2.4.22/Documentation/hw_random.txt linux-2.4.23/Documentation/hw_random.txt
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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 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.
+
+Change history:
+
+	Version 1.0.0:
+	* Merge Intel, AMD, VIA RNG drivers into one.
+	  Further changelog in BitKeeper.
+
+	Version 0.9.8:
+	* Support other i8xx chipsets by adding 82801E detection
+	* 82801DB detection is the same as for 82801CA.
+
+	Version 0.9.7:
+	* Support other i8xx chipsets too (by adding 82801BA(M) and
+	  82801CA(M) detection)
+
+	Version 0.9.6:
+	* Internal driver cleanups, prep for 1.0.0 release.
+
+	Version 0.9.5:
+	* Rip out entropy injection via timer.  It never ever worked,
+	  and a better solution (rngd) is now available.
+
+	Version 0.9.4:
+	* Fix: Remove request_mem_region
+	* Fix: Horrible bugs in FIPS calculation and test execution
+
+	Version 0.9.3:
+	* Clean up rng_read a bit.
+	* Update i810_rng driver Web site URL.
+	* Increase default timer interval to 4 samples per second.
+	* Abort if mem region is not available.
+	* BSS zero-initialization cleanup.
+	* Call misc_register() from rng_init_one.
+	* Fix O_NONBLOCK to occur before we schedule.
+
+	Version 0.9.2:
+	* Simplify open blocking logic
+
+	Version 0.9.1:
+	* Support i815 chipsets too (Matt Sottek)
+	* Fix reference counting when statically compiled (prumpf)
+	* Rewrite rng_dev_read (prumpf)
+	* Make module races less likely (prumpf)
+	* Small miscellaneous bug fixes (prumpf)
+	* Use pci table for PCI id list
+
+	Version 0.9.0:
+	* Don't register a pci_driver, because we are really
+	  using PCI bridge vendor/device ids, and someone
+	  may want to register a driver for the bridge. (bug fix)
+	* Don't let the usage count go negative (bug fix)
+	* Clean up spinlocks (bug fix)
+	* Enable PCI device, if necessary (bug fix)
+	* iounmap on module unload (bug fix)
+	* If RNG chrdev is already in use when open(2) is called,
+	  sleep until it is available.
+	* Remove redundant globals rng_allocated, rng_use_count
+	* Convert numeric globals to unsigned
+	* Module unload cleanup
+
+	Version 0.6.2:
+	* Clean up spinlocks.  Since we don't have any interrupts
+	  to worry about, but we do have a timer to worry about,
+	  we use spin_lock_bh everywhere except the timer function
+	  itself.
+	* Fix module load/unload.
+	* Fix timer function and h/w enable/disable logic
+	* New timer interval sysctl
+	* Clean up sysctl names