Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755356AbbK0VJt (ORCPT ); Fri, 27 Nov 2015 16:09:49 -0500 Received: from mail-wm0-f51.google.com ([74.125.82.51]:35098 "EHLO mail-wm0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755026AbbK0VJl (ORCPT ); Fri, 27 Nov 2015 16:09:41 -0500 From: Matt Fleming To: Ingo Molnar , Thomas Gleixner , "H . Peter Anvin" Cc: Toshi Kani , Matt Fleming , linux-kernel@vger.kernel.org, linux-efi@vger.kernel.org, Sai Praneeth Prakhya , Dave Hansen , Borislav Petkov Subject: [PATCH v4 2/6] x86/mm/pageattr: Ensure cpa->pfn only contains page frame numbers Date: Fri, 27 Nov 2015 21:09:31 +0000 Message-Id: <1448658575-17029-3-git-send-email-matt@codeblueprint.co.uk> X-Mailer: git-send-email 2.6.2 In-Reply-To: <1448658575-17029-1-git-send-email-matt@codeblueprint.co.uk> References: <1448658575-17029-1-git-send-email-matt@codeblueprint.co.uk> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4695 Lines: 133 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. Reviewed-by: Borislav Petkov Cc: Sai Praneeth Prakhya Cc: Dave Hansen Signed-off-by: Matt Fleming --- arch/x86/mm/pageattr.c | 17 ++++++----------- arch/x86/platform/efi/efi_64.c | 16 ++++++++++------ 2 files changed, 16 insertions(+), 17 deletions(-) diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index a3137a4feed1..c70e42014101 100644 --- 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 a0ac0f9c307f..5aa186db59e3 100644 --- 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); } -- 2.6.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/