Commit Graph

19 Commits

Author SHA1 Message Date
David Malone
93f39ea88a Some BIOSs are using MTRR values that are only documented under NDA
to control the mapping of things like the ACPI and APM into memory.

The problem is that starting X changes these values, so if something
was using the bits of BIOS mapped into memory (say ACPI or APM),
then next time they access this memory the machine would hang.

This patch refuse to change MTRR values it doesn't understand,
unless a new "force" option is given. This means X doesn't change
them by accident but someone can override that if they really want
to.

PR:		28418
Tested by:	Christopher Masto <chris@netmonger.net>,
		David Bushong <david@bushong.net>,
		Santos <casd@myrealbox.com>
MFC after:	1 week
2002-09-15 15:07:55 +00:00
Philippe Charnier
490d5836b5 The .Nm utility 2002-07-14 14:47:15 +00:00
David Malone
b0f4bb511e Make the MTRR code a bit more defensive - this should help people
trying to run X on some Athlon systems where the BIOS does odd things
(mines an ASUS A7A266, but it seems to also help on other systems).

Here's a description of the problem and my fix:

        The problem with the old MTRR code is that it only expects
        to find documented values in the bytes of MTRR registers.
        To convert the MTRR byte into a FreeBSD "Memory Range Type"
        (mrt) it uses the byte value and looks it up in an array.
        If the value is not in range then the mrt value ends up
        containing random junk.

        This isn't an immediate problem. The mrt value is only used
        later when rewriting the MTRR registers. When we finally
        go to write a value back again, the function i686_mtrrtype()
        searches for the junk value and returns -1 when it fails
        to find it. This is converted to a byte (0xff) and written
        back to the register, causing a GPF as 0xff is an illegal
        value for a MTRR byte.

	To work around this problem I've added a new mrt flag
	MDF_UNKNOWN.  We set this when we read a MTRR byte which
	we do not understand.  If we try to convert a MDF_UNKNOWN
	back into a MTRR value, then the new function, i686_mrt2mtrr,
	just returns the old value of the MTRR byte. This leaves
	the memory range type unchanged.

I have seen one side effect of the fix, which is that ACPI calls
after X has been run seem to hang my machine. As running X would
previously panic the machine, this is still an improvement ;-)

I'd like to MFC this before the 4.6 code freeze - please let me
know if it causes any problems.

PR:		28418, 25958
Tested by:	jkh, Christopher Masto <chris@netmonger.net>
MFC after:	2 weeks
2002-04-14 20:19:13 +00:00
David E. O'Brien
90e655ea4e Perform a major cleanup of the usr.sbin Makefiles.
These are not perfectly in agreement with each other style-wise, but they
are orders of orders of magnitude more consistent style-wise than before.
2001-07-20 06:20:32 +00:00
Dima Dorfman
f247324df7 Remove whitespace at EOL. 2001-07-15 08:06:20 +00:00
Ruslan Ermilov
a4c37c816b mdoc(7) police: removed HISTORY info from the .Os call. 2001-07-10 15:12:08 +00:00
Dima Dorfman
7309915e7a Nuke unused variables. 2001-06-24 23:41:57 +00:00
Ruslan Ermilov
eb0838029f mdoc(7) police: normalize .Nd. 2001-04-18 15:54:10 +00:00
Ruslan Ermilov
345e52e742 - Backout botched attempt to introduce MANSECT feature.
- MAN[1-9] -> MAN.
2001-03-26 14:42:20 +00:00
Ruslan Ermilov
c73e22c3d4 Set the default manual section for usr.sbin/ to 8. 2001-03-20 18:17:26 +00:00
David E. O'Brien
1a37aa566b Add `_PATH_DEVZERO'.
Use _PATH_* where where possible.
2000-12-09 09:35:55 +00:00
Ruslan Ermilov
e97407b4f2 mdoc(7) police: use the new features of the Nm macro. 2000-11-20 20:10:44 +00:00
Brian Feldman
2e61f987ad Make memcontrol(8) able to delete the segments starting at a base of 0
which it can create..
2000-03-20 22:53:32 +00:00
Sheldon Hearn
f2e366a105 Remove single-space hard sentence breaks. These degrade the quality
of the typeset output, tend to make diffs harder to read and provide
bad examples for new-comers to mdoc.
2000-03-01 14:09:25 +00:00
Chris Costello
f63b242474 Remove an unnecessary cross-reference to ioctl(2) 1999-10-09 16:37:37 +00:00
Chris Costello
48b7ea76f0 Add and activate the man page for memcontrol(8).
Reviewed by:	msmith
1999-09-29 21:43:31 +00:00
Peter Wemm
97d92980a9 $Id$ -> $FreeBSD$ 1999-08-28 01:35:59 +00:00
Mike Smith
5fd6b620bb Make memcontrol's internal help actually work. No substitute for a real
manpage, but at least now you can get syntax help without resorting
to reading the source.
1999-07-20 04:33:14 +00:00
Mike Smith
53f17f08ba Commandline tool for manipulating memory range attributes. 1999-04-07 04:11:14 +00:00