• Linus Torvalds's avatar
    i386: remove bogus mtrr range check · 4710bcce
    Linus Torvalds authored
    Commit 9215da33 "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: default avatarLuca Palermo <darkmage@sabayonlinux.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    4710bcce
generic.c 14.6 KB