x86/mm: Fix gup_huge_p?d() to handle large PAT bit

gup_huge_pud() and gup_huge_pmd() cast *pud and *pmd to *pte,
and use pte_xxx() interfaces to obtain the flags and PFN.
However, the pte_xxx() interface does not handle the large
PAT bit properly for PUD/PMD.

Fix gup_huge_pud() and gup_huge_pmd() to use pud_xxx() and
pmd_xxx() interfaces according to their type.

Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Juergen Gross <jgross@suse.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Konrad Wilk <konrad.wilk@oracle.com>
Cc: Robert Elliot <elliott@hpe.com>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/1442514264-12475-9-git-send-email-toshi.kani@hpe.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/arch/x86/mm/gup.c b/arch/x86/mm/gup.c
index 81bf3d2..ae9a37b 100644 (file)
--- a/arch/x86/mm/gup.c
+++ b/arch/x86/mm/gup.c
@@ -118,21 +118,20 @@ static noinline int gup_huge_pmd(pmd_t pmd, unsigned long addr,
                unsigned long end, int write, struct page **pages, int *nr)
 {
        unsigned long mask;
-       pte_t pte = *(pte_t *)&pmd;
        struct page *head, *page;
        int refs;
 
        mask = _PAGE_PRESENT|_PAGE_USER;
        if (write)
                mask |= _PAGE_RW;
-       if ((pte_flags(pte) & mask) != mask)
+       if ((pmd_flags(pmd) & mask) != mask)
                return 0;
        /* hugepages are never "special" */
-       VM_BUG_ON(pte_flags(pte) & _PAGE_SPECIAL);
-       VM_BUG_ON(!pfn_valid(pte_pfn(pte)));
+       VM_BUG_ON(pmd_flags(pmd) & _PAGE_SPECIAL);
+       VM_BUG_ON(!pfn_valid(pmd_pfn(pmd)));
 
        refs = 0;
-       head = pte_page(pte);
+       head = pmd_page(pmd);
        page = head + ((addr & ~PMD_MASK) >> PAGE_SHIFT);
        do {
                VM_BUG_ON_PAGE(compound_head(page) != head, page);
@@ -195,21 +194,20 @@ static noinline int gup_huge_pud(pud_t pud, unsigned long addr,
                unsigned long end, int write, struct page **pages, int *nr)
 {
        unsigned long mask;
-       pte_t pte = *(pte_t *)&pud;
        struct page *head, *page;
        int refs;
 
        mask = _PAGE_PRESENT|_PAGE_USER;
        if (write)
                mask |= _PAGE_RW;
-       if ((pte_flags(pte) & mask) != mask)
+       if ((pud_flags(pud) & mask) != mask)
                return 0;
        /* hugepages are never "special" */
-       VM_BUG_ON(pte_flags(pte) & _PAGE_SPECIAL);
-       VM_BUG_ON(!pfn_valid(pte_pfn(pte)));
+       VM_BUG_ON(pud_flags(pud) & _PAGE_SPECIAL);
+       VM_BUG_ON(!pfn_valid(pud_pfn(pud)));
 
        refs = 0;
-       head = pte_page(pte);
+       head = pud_page(pud);
        page = head + ((addr & ~PUD_MASK) >> PAGE_SHIFT);
        do {
                VM_BUG_ON_PAGE(compound_head(page) != head, page);