From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matt Fleming Subject: [PATCH 3/6] x86/efi: Map RAM into the identity page table for mixed mode Date: Thu, 12 Nov 2015 15:40:20 +0000 Message-ID: <1447342823-3612-4-git-send-email-matt@codeblueprint.co.uk> References: <1447342823-3612-1-git-send-email-matt@codeblueprint.co.uk> Return-path: In-Reply-To: <1447342823-3612-1-git-send-email-matt@codeblueprint.co.uk> Sender: linux-kernel-owner@vger.kernel.org To: Ingo Molnar , Thomas Gleixner , "H . Peter Anvin" Cc: Toshi Kani , Matt Fleming , linux-kernel@vger.kernel.org, linux-efi@vger.kernel.org, Borislav Petkov , Sai Praneeth Prakhya List-Id: linux-efi@vger.kernel.org We are relying on the pre-existing mappings in 'trampoline_pgd' when accessing function arguments in the EFI mixed mode thunking code. Instead let's map memory explicitly so that things will continue to work when we move to a separate page table in the future. Cc: Borislav Petkov Cc: Sai Praneeth Prakhya Signed-off-by: Matt Fleming --- arch/x86/platform/efi/efi_64.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c index c8b58ac47b77..634536034e32 100644 --- a/arch/x86/platform/efi/efi_64.c +++ b/arch/x86/platform/efi/efi_64.c @@ -144,6 +144,7 @@ void efi_sync_low_kernel_mappings(void) int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages) { unsigned long pfn, text; + efi_memory_desc_t *md; struct page *page; unsigned npages; pgd_t *pgd; @@ -200,6 +201,25 @@ int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages) efi_scratch.phys_stack += PAGE_SIZE; /* stack grows down */ + /* + * Map all of RAM so that we can access arguments in the 1:1 + * mapping when making EFI runtime calls. + */ + for_each_efi_memory_desc(&memmap, md) { + if (md->type != EFI_CONVENTIONAL_MEMORY && + md->type != EFI_LOADER_DATA && + md->type != EFI_LOADER_CODE) + continue; + + pfn = md->phys_addr >> PAGE_SHIFT; + npages = md->num_pages; + + if (kernel_map_pages_in_pgd(pgd, pfn, md->phys_addr, npages, 0)) { + pr_err("Failed to map 1:1 memory\n"); + return 1; + } + } + return 0; } -- 2.6.2