From d886c73cd4cf02a71e1650cbcb6176799d78aac1 Mon Sep 17 00:00:00 2001 From: Venkatesh Pallipadi Date: Fri, 10 Jul 2009 09:57:41 -0700 Subject: [PATCH] x86, pat: Sanity check remap_pfn_range for RAM region 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 Signed-off-by: Suresh Siddha Signed-off-by: H. Peter Anvin --- arch/x86/mm/pat.c | 24 +++++++++++++++++++++--- 1 file changed, 21 insertions(+), 3 deletions(-) diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c index b629f75f73de..a6cace0694a2 100644 --- a/arch/x86/mm/pat.c +++ b/arch/x86/mm/pat.c @@ -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); /* - * reserve_pfn_range() doesn't support RAM pages. Maintain the current - * behavior with RAM pages by returning success. + * reserve_pfn_range() for RAM pages. We do not refcount to keep + * 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; + } ret = reserve_memtype(paddr, paddr + size, want_flags, &flags); if (ret) -- 2.34.1