Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752188AbbKNWB5 (ORCPT ); Sat, 14 Nov 2015 17:01:57 -0500 Received: from mail-wm0-f52.google.com ([74.125.82.52]:34477 "EHLO mail-wm0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751865AbbKNWAz (ORCPT ); Sat, 14 Nov 2015 17:00:55 -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 v2 1/5] x86/mm/pageattr: Ensure cpa->pfn only contains page frame numbers Date: Sat, 14 Nov 2015 22:00:47 +0000 Message-Id: <1447538451-5793-2-git-send-email-matt@codeblueprint.co.uk> X-Mailer: git-send-email 2.6.2 In-Reply-To: <1447538451-5793-1-git-send-email-matt@codeblueprint.co.uk> References: <1447538451-5793-1-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: 5443 Lines: 162 The x86 pageattr code is confused about the data that is stored 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 mappings 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 --- Changes in v2: - Folded the deletion of the _PAGE_NX code into this patch. arch/x86/mm/pageattr.c | 17 ++++++----------- arch/x86/platform/efi/efi_64.c | 33 ++++++++++++++++++++++----------- 2 files changed, 28 insertions(+), 22 deletions(-) diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index 9abe0c9b1098..d5240be55915 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -885,15 +885,10 @@ 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++; } } @@ -949,11 +944,11 @@ 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; } @@ -1022,11 +1017,11 @@ 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..c8b58ac47b77 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; } @@ -176,21 +177,29 @@ int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages) if (!IS_ENABLED(CONFIG_EFI_MIXED)) return 0; + npages = (_end - _text) >> PAGE_SHIFT; + text = __pa(_text); + pfn = text >> PAGE_SHIFT; + + if (kernel_map_pages_in_pgd(pgd, pfn, text, npages, 0)) { + pr_err("Failed to map kernel text 1:1\n"); + return 1; + } + page = alloc_page(GFP_KERNEL|__GFP_DMA32); if (!page) panic("Unable to allocate EFI runtime stack < 4GB\n"); efi_scratch.phys_stack = virt_to_phys(page_address(page)); - efi_scratch.phys_stack += PAGE_SIZE; /* stack grows down */ - - npages = (_end - _text) >> PAGE_SHIFT; - text = __pa(_text); + pfn = page_to_pfn(page); - if (kernel_map_pages_in_pgd(pgd, text >> PAGE_SHIFT, text, npages, 0)) { - pr_err("Failed to map kernel text 1:1\n"); + if (kernel_map_pages_in_pgd(pgd, pfn, efi_scratch.phys_stack, 1, 0)) { + pr_err("Failed to map mixed mode stack\n"); return 1; } + efi_scratch.phys_stack += PAGE_SIZE; /* stack grows down */ + return 0; } @@ -204,12 +213,14 @@ 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/