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x86, pat: Sanity check remap_pfn_range for RAM region

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Add sanity check for remap_pfn_range of RAM regions using
lookup_memtype(). Previously, we did not have anyway to get the type of
RAM memory regions as they were tracked using a single bit in
page_struct (WB, nonWB). Now we can get the actual type from page struct
(WB, WC, UC_MINUS) and make sure the requester gets that type.

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
This commit is contained in:
Venkatesh Pallipadi 2009-07-10 09:57:41 -07:00 committed by H. Peter Anvin
parent 1087637616
commit d886c73cd4
1 changed files with 21 additions and 3 deletions
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24
arch/x86/mm/pat.c
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@ -783,11 +783,29 @@ static int reserve_pfn_range(u64 paddr, unsigned long size, pgprot_t *vma_prot,
is_ram = pat_pagerange_is_ram(paddr, paddr + size); is_ram = pat_pagerange_is_ram(paddr, paddr + size);
/* /*
* reserve_pfn_range() doesn't support RAM pages. Maintain the current * reserve_pfn_range() for RAM pages. We do not refcount to keep
* behavior with RAM pages by returning success. * track of number of mappings of RAM pages. We can assert that
* the type requested matches the type of first page in the range.
*/ */
if (is_ram != 0) if (is_ram) {
if (!pat_enabled)
return 0;
flags = lookup_memtype(paddr);
if (want_flags != flags) {
printk(KERN_WARNING
"%s:%d map pfn RAM range req %s for %Lx-%Lx, got %s\n",
current->comm, current->pid,
cattr_name(want_flags),
(unsigned long long)paddr,
(unsigned long long)(paddr + size),
cattr_name(flags));
*vma_prot = __pgprot((pgprot_val(*vma_prot) &
(~_PAGE_CACHE_MASK)) |
flags);
}
return 0; return 0;
}
ret = reserve_memtype(paddr, paddr + size, want_flags, &flags); ret = reserve_memtype(paddr, paddr + size, want_flags, &flags);
if (ret) if (ret)