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x86: Exclude E820_RESERVED regions and memory holes above 4 GB from direct mapping.

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On systems with very large memory (1 TB in our case), BIOS may report a
reserved region or a hole in the E820 map, even above the 4 GB range. Exclude
these from the direct mapping.

[ hpa: this should be done not just for > 4 GB but for everything above the legacy
  region (1 MB), at the very least.  That, however, turns out to require significant
  restructuring.  That work is well underway, but is not suitable for rc/stable. ]

Cc: stable@kernel.org   # > 2.6.32
Signed-off-by: Jacob Shin <jacob.shin@amd.com>
Link: http://lkml.kernel.org/r/1319145326-13902-1-git-send-email-jacob.shin@amd.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
This commit is contained in:
Jacob Shin 2011-10-20 16:15:26 -05:00 committed by H. Peter Anvin
parent 961c79761d
commit 1bbbbe779a
1 changed files with 15 additions and 2 deletions
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17
arch/x86/kernel/setup.c
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@ -919,8 +919,21 @@ void __init setup_arch(char **cmdline_p)
#ifdef CONFIG_X86_64
if (max_pfn > max_low_pfn) {
max_pfn_mapped = init_memory_mapping(1UL<<32,
max_pfn<<PAGE_SHIFT);
int i;
for (i = 0; i < e820.nr_map; i++) {
struct e820entry *ei = &e820.map[i];
if (ei->addr + ei->size <= 1UL << 32)
continue;
if (ei->type == E820_RESERVED)
continue;
max_pfn_mapped = init_memory_mapping(
ei->addr < 1UL << 32 ? 1UL << 32 : ei->addr,
ei->addr + ei->size);
}
/* can we preseve max_low_pfn ?*/
max_low_pfn = max_pfn;
}