x86/mm: Fix try_preserve_large_page() to handle large PAT bit

try_preserve_large_page() is called from __change_page_attr() to
change the mapping attribute of a given large page.  This function
uses pte_pfn() and pte_pgprot() for PUD/PMD, which do not handle
the large PAT bit properly.

Fix try_preserve_large_page() by using the corresponding pud/pmd
prot/pfn interfaces.

Also remove '#ifdef CONFIG_X86_64', which is not necessary.

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/1442514264-12475-10-git-send-email-toshi.kani@hpe.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 1441368a79319427fdf549ca130ccccf72a5068f..3f612713159a247628ea65f0bdacfa843fdb20a1 100644 (file)
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -468,7 +468,7 @@ static int
 try_preserve_large_page(pte_t *kpte, unsigned long address,
                        struct cpa_data *cpa)
 {
-       unsigned long nextpage_addr, numpages, pmask, psize, addr, pfn;
+       unsigned long nextpage_addr, numpages, pmask, psize, addr, pfn, old_pfn;
        pte_t new_pte, old_pte, *tmp;
        pgprot_t old_prot, new_prot, req_prot;
        int i, do_split = 1;
@@ -488,17 +488,21 @@ try_preserve_large_page(pte_t *kpte, unsigned long address,
 
        switch (level) {
        case PG_LEVEL_2M:
-#ifdef CONFIG_X86_64
+               old_prot = pmd_pgprot(*(pmd_t *)kpte);
+               old_pfn = pmd_pfn(*(pmd_t *)kpte);
+               break;
        case PG_LEVEL_1G:
-#endif
-               psize = page_level_size(level);
-               pmask = page_level_mask(level);
+               old_prot = pud_pgprot(*(pud_t *)kpte);
+               old_pfn = pud_pfn(*(pud_t *)kpte);
                break;
        default:
                do_split = -EINVAL;
                goto out_unlock;
        }
 
+       psize = page_level_size(level);
+       pmask = page_level_mask(level);
+
        /*
         * Calculate the number of pages, which fit into this large
         * page starting at address:
@@ -514,7 +518,7 @@ try_preserve_large_page(pte_t *kpte, unsigned long address,
         * up accordingly.
         */
        old_pte = *kpte;
-       old_prot = req_prot = pgprot_large_2_4k(pte_pgprot(old_pte));
+       old_prot = req_prot = pgprot_large_2_4k(old_prot);
 
        pgprot_val(req_prot) &= ~pgprot_val(cpa->mask_clr);
        pgprot_val(req_prot) |= pgprot_val(cpa->mask_set);
@@ -540,10 +544,10 @@ try_preserve_large_page(pte_t *kpte, unsigned long address,
        req_prot = canon_pgprot(req_prot);
 
        /*
-        * old_pte points to the large page base address. So we need
+        * old_pfn points to the large page base pfn. So we need
         * to add the offset of the virtual address:
         */
-       pfn = pte_pfn(old_pte) + ((address & (psize - 1)) >> PAGE_SHIFT);
+       pfn = old_pfn + ((address & (psize - 1)) >> PAGE_SHIFT);
        cpa->pfn = pfn;
 
        new_prot = static_protections(req_prot, address, pfn);
@@ -554,7 +558,7 @@ try_preserve_large_page(pte_t *kpte, unsigned long address,
         * the pages in the range we try to preserve:
         */
        addr = address & pmask;
-       pfn = pte_pfn(old_pte);
+       pfn = old_pfn;
        for (i = 0; i < (psize >> PAGE_SHIFT); i++, addr += PAGE_SIZE, pfn++) {
                pgprot_t chk_prot = static_protections(req_prot, addr, pfn);
 
@@ -584,7 +588,7 @@ try_preserve_large_page(pte_t *kpte, unsigned long address,
                 * The address is aligned and the number of pages
                 * covers the full page.
                 */
-               new_pte = pfn_pte(pte_pfn(old_pte), new_prot);
+               new_pte = pfn_pte(old_pfn, new_prot);
                __set_pmd_pte(kpte, address, new_pte);
                cpa->flags |= CPA_FLUSHTLB;
                do_split = 0;