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26 November 2022, 15:45:29 UTC
Revision 4710bcce8e02257c8a423b7a62ea81d0207582c8 authored by Linus Torvalds on 01 July 2007, 17:56:11 UTC, committed by Linus Torvalds on 01 July 2007, 17:56:11 UTC 
i386: remove bogus mtrr range check
 
Commit 9215da33209b861b01c51382254b178a3fe92a30 "fixed" the MTRR range
check to not allow any MTRR's under the 1MB mark (since that's where the
fixed MTRR's are active).

However, that was totally bogus, since it's normal (and almost required)
to have a large variable MTRR that starts at 0, and covers some large
percentage of the whole RAM, and then using the fixed MTRR's to override
that large MTRR to handle the special ISA hole in the 640k-1M region.

The old check was bogus too (checking that no variable MTRR is used that
is entirely under the 1MB range), but at least it wasn't actively
detrimental, because no sane situation would ever trigger such MTRR
usage in the first place.

That said, the whole notion of not allowing variable MTRR's in the low
1MB is just stupid, so rather than revert the commit, this just removes
the whole sad and unnecessary check entirely.

Cc: Jan Beulich <jbeulich@novell.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Luca Palermo <darkmage@sabayonlinux.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent abdba71
History
Tip revision: 4710bcce8e02257c8a423b7a62ea81d0207582c8 authored by Linus Torvalds on 01 July 2007, 17:56:11 UTC
i386: remove bogus mtrr range check
Tip revision: 4710bcc
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