[PATCH] i386: fix buggy MTRR address checks
Fix checks that failed to realize that values are 4-kB-unit-sized (note the format strings in this same diff context which *do* realize the unit size, via appended "000"!). Also fix an incorrect below-1MB area check (as gathered from Jan Beulich's unapplied patch at http://www.ussg.iu.edu/hypermail/linux/kernel/0411.1/1378.html ) Update mtrr_add_page() docu to make 4-kB-sized calculation more obvious. Given several further items mentioned in Jan's patch mail, all in all MTRR code seems surprisingly buggy, for a surprisingly long period of time (many years). Further work/investigation would be useful. TBD Note that my patch is pretty much UNTESTED, since I can only verify that it TBD successfully boots my machine, but I cannot test against actual buggy TBD hardware which would require these (formerly broken) checks. Long -mm TBD simmering would make sense, especially since these now-working checks might TBD turn out to have adverse effects on unaffected hardware. Signed-off-by: Andreas Mohr <andi@lisas.de> Signed-off-by: Andi Kleen <ak@suse.de> Acked-by: Jan Beulich <jbeulich@novell.com> Cc: Andi Kleen <ak@muc.de> Signed-off-by: Andrew Morton <akpm@osdl.org>
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@ -366,7 +366,7 @@ int generic_validate_add_page(unsigned long base, unsigned long size, unsigned i
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printk(KERN_WARNING "mtrr: base(0x%lx000) is not 4 MiB aligned\n", base);
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printk(KERN_WARNING "mtrr: base(0x%lx000) is not 4 MiB aligned\n", base);
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return -EINVAL;
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return -EINVAL;
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}
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}
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if (!(base + size < 0x70000000 || base > 0x7003FFFF) &&
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if (!(base + size < 0x70000 || base > 0x7003F) &&
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(type == MTRR_TYPE_WRCOMB
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(type == MTRR_TYPE_WRCOMB
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|| type == MTRR_TYPE_WRBACK)) {
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|| type == MTRR_TYPE_WRBACK)) {
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printk(KERN_WARNING "mtrr: writable mtrr between 0x70000000 and 0x7003FFFF may hang the CPU.\n");
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printk(KERN_WARNING "mtrr: writable mtrr between 0x70000000 and 0x7003FFFF may hang the CPU.\n");
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@ -374,7 +374,7 @@ int generic_validate_add_page(unsigned long base, unsigned long size, unsigned i
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}
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}
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}
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}
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if (base + size < 0x100) {
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if (base < 0x100) {
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printk(KERN_WARNING "mtrr: cannot set region below 1 MiB (0x%lx000,0x%lx000)\n",
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printk(KERN_WARNING "mtrr: cannot set region below 1 MiB (0x%lx000,0x%lx000)\n",
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base, size);
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base, size);
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return -EINVAL;
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return -EINVAL;
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@ -263,8 +263,8 @@ static void set_mtrr(unsigned int reg, unsigned long base,
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/**
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/**
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* mtrr_add_page - Add a memory type region
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* mtrr_add_page - Add a memory type region
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* @base: Physical base address of region in pages (4 KB)
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* @base: Physical base address of region in pages (in units of 4 kB!)
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* @size: Physical size of region in pages (4 KB)
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* @size: Physical size of region in pages (4 kB)
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* @type: Type of MTRR desired
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* @type: Type of MTRR desired
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* @increment: If this is true do usage counting on the region
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* @increment: If this is true do usage counting on the region
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*
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*
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