From 4710bcce8e02257c8a423b7a62ea81d0207582c8 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sun, 1 Jul 2007 10:56:11 -0700 Subject: [PATCH] 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 Cc: Andi Kleen Cc: Andrew Morton Tested-by: Luca Palermo Signed-off-by: Linus Torvalds --- arch/i386/kernel/cpu/mtrr/generic.c | 5 ----- 1 file changed, 5 deletions(-) diff --git a/arch/i386/kernel/cpu/mtrr/generic.c b/arch/i386/kernel/cpu/mtrr/generic.c index 6d5937891b46..5a551fb7ea7b 100644 --- a/arch/i386/kernel/cpu/mtrr/generic.c +++ b/arch/i386/kernel/cpu/mtrr/generic.c @@ -469,11 +469,6 @@ int generic_validate_add_page(unsigned long base, unsigned long size, unsigned i } } - if (base < 0x100) { - printk(KERN_WARNING "mtrr: cannot set region below 1 MiB (0x%lx000,0x%lx000)\n", - base, size); - return -EINVAL; - } /* Check upper bits of base and last are equal and lower bits are 0 for base and 1 for last */ last = base + size - 1; -- 2.11.0