x86/mm/pat: Ensure cpa->pfn only contains page frame numbers

The x86 pageattr code is confused about the data that is stored
in cpa->pfn, sometimes it's treated as a page frame number,
sometimes it's treated as an unshifted physical address, and in
one place it's treated as a pte.

The result of this is that the mapping functions do not map the
intended physical address.

This isn't a problem in practice because most of the addresses
we're mapping in the EFI code paths are already mapped in
'trampoline_pgd' and so the pageattr mapping functions don't
actually do anything in this case. But when we move to using a
separate page table for the EFI runtime this will be an issue.

Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Reviewed-by: Borislav Petkov <bp@suse.de>
Acked-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1448658575-17029-3-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index a3137a4feed15ed0d58189411e4e1ae2d9236e8a..c70e420141017545db709807db8d259aa2e2bab2 100644 (file)
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -905,15 +905,10 @@ static void populate_pte(struct cpa_data *cpa,
        pte = pte_offset_kernel(pmd, start);
 
        while (num_pages-- && start < end) {
-
-               /* deal with the NX bit */
-               if (!(pgprot_val(pgprot) & _PAGE_NX))
-                       cpa->pfn &= ~_PAGE_NX;
-
-               set_pte(pte, pfn_pte(cpa->pfn >> PAGE_SHIFT, pgprot));
+               set_pte(pte, pfn_pte(cpa->pfn, pgprot));
 
                start    += PAGE_SIZE;
-               cpa->pfn += PAGE_SIZE;
+               cpa->pfn++;
                pte++;
        }
 }
@@ -969,11 +964,11 @@ static int populate_pmd(struct cpa_data *cpa,
 
                pmd = pmd_offset(pud, start);
 
-               set_pmd(pmd, __pmd(cpa->pfn | _PAGE_PSE |
+               set_pmd(pmd, __pmd(cpa->pfn << PAGE_SHIFT | _PAGE_PSE |
                                   massage_pgprot(pmd_pgprot)));
 
                start     += PMD_SIZE;
-               cpa->pfn  += PMD_SIZE;
+               cpa->pfn  += PMD_SIZE >> PAGE_SHIFT;
                cur_pages += PMD_SIZE >> PAGE_SHIFT;
        }
 
@@ -1042,11 +1037,11 @@ static int populate_pud(struct cpa_data *cpa, unsigned long start, pgd_t *pgd,
         * Map everything starting from the Gb boundary, possibly with 1G pages
         */
        while (end - start >= PUD_SIZE) {
-               set_pud(pud, __pud(cpa->pfn | _PAGE_PSE |
+               set_pud(pud, __pud(cpa->pfn << PAGE_SHIFT | _PAGE_PSE |
                                   massage_pgprot(pud_pgprot)));
 
                start     += PUD_SIZE;
-               cpa->pfn  += PUD_SIZE;
+               cpa->pfn  += PUD_SIZE >> PAGE_SHIFT;
                cur_pages += PUD_SIZE >> PAGE_SHIFT;
                pud++;
        }

diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c
index a0ac0f9c307f661c8b3ed08c4ca6d23507772e36..5aa186db59e37000fc267f6c55d1006a1618bf1f 100644 (file)
--- a/arch/x86/platform/efi/efi_64.c
+++ b/arch/x86/platform/efi/efi_64.c
@@ -143,7 +143,7 @@ void efi_sync_low_kernel_mappings(void)
 
 int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages)
 {
-       unsigned long text;
+       unsigned long pfn, text;
        struct page *page;
        unsigned npages;
        pgd_t *pgd;
@@ -160,7 +160,8 @@ int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages)
         * and ident-map those pages containing the map before calling
         * phys_efi_set_virtual_address_map().
         */
-       if (kernel_map_pages_in_pgd(pgd, pa_memmap, pa_memmap, num_pages, _PAGE_NX)) {
+       pfn = pa_memmap >> PAGE_SHIFT;
+       if (kernel_map_pages_in_pgd(pgd, pfn, pa_memmap, num_pages, _PAGE_NX)) {
                pr_err("Error ident-mapping new memmap (0x%lx)!\n", pa_memmap);
                return 1;
        }
@@ -185,8 +186,9 @@ int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages)
 
        npages = (_end - _text) >> PAGE_SHIFT;
        text = __pa(_text);
+       pfn = text >> PAGE_SHIFT;
 
-       if (kernel_map_pages_in_pgd(pgd, text >> PAGE_SHIFT, text, npages, 0)) {
+       if (kernel_map_pages_in_pgd(pgd, pfn, text, npages, 0)) {
                pr_err("Failed to map kernel text 1:1\n");
                return 1;
        }
@@ -204,12 +206,14 @@ void __init efi_cleanup_page_tables(unsigned long pa_memmap, unsigned num_pages)
 static void __init __map_region(efi_memory_desc_t *md, u64 va)
 {
        pgd_t *pgd = (pgd_t *)__va(real_mode_header->trampoline_pgd);
-       unsigned long pf = 0;
+       unsigned long flags = 0;
+       unsigned long pfn;
 
        if (!(md->attribute & EFI_MEMORY_WB))
-               pf |= _PAGE_PCD;
+               flags |= _PAGE_PCD;
 
-       if (kernel_map_pages_in_pgd(pgd, md->phys_addr, va, md->num_pages, pf))
+       pfn = md->phys_addr >> PAGE_SHIFT;
+       if (kernel_map_pages_in_pgd(pgd, pfn, va, md->num_pages, flags))
                pr_warn("Error mapping PA 0x%llx -> VA 0x%llx!\n",
                           md->phys_addr, va);
 }