Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754246AbbKLSBc (ORCPT ); Thu, 12 Nov 2015 13:01:32 -0500 Received: from mail.skyhub.de ([78.46.96.112]:51324 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754078AbbKLSBa (ORCPT ); Thu, 12 Nov 2015 13:01:30 -0500 Date: Thu, 12 Nov 2015 19:01:26 +0100 From: Borislav Petkov To: Matt Fleming Cc: Ingo Molnar , Thomas Gleixner , "H . Peter Anvin" , Toshi Kani , linux-kernel@vger.kernel.org, linux-efi@vger.kernel.org, Sai Praneeth Prakhya Subject: Re: [PATCH 3/6] x86/efi: Map RAM into the identity page table for mixed mode Message-ID: <20151112180126.GD3838@pd.tnic> References: <1447342823-3612-1-git-send-email-matt@codeblueprint.co.uk> <1447342823-3612-4-git-send-email-matt@codeblueprint.co.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <1447342823-3612-4-git-send-email-matt@codeblueprint.co.uk> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2198 Lines: 73 On Thu, Nov 12, 2015 at 03:40:20PM +0000, Matt Fleming wrote: > 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 Why "all of RAM"? > + * 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) That's mapping all those EFI_* types... > + 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 > > -- Regards/Gruss, Boris. ECO tip #101: Trim your mails when you reply. -- 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/