From patchwork Fri Jul 28 09:09:10 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ard Biesheuvel X-Patchwork-Id: 708963 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 170D3C00528 for ; Fri, 28 Jul 2023 09:13:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233472AbjG1JNi (ORCPT ); Fri, 28 Jul 2023 05:13:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33956 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235455AbjG1JND (ORCPT ); Fri, 28 Jul 2023 05:13:03 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5119749E4; Fri, 28 Jul 2023 02:11:51 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id BD70562086; Fri, 28 Jul 2023 09:11:50 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6530FC433C7; Fri, 28 Jul 2023 09:11:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1690535510; bh=2+7iwEobaM7sVn9y3ZDpX6mWLwOi48XQ2V4eIw6Xv00=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=r/Ry7g4M2JyKRAprdaf8CjNvMTK66dOKkNyOWQmZ/ZOAbPn7aO8+xLesw2AO56fem myrvWUb1JCsTZ+GaZkzu7XAg6eUzT1X1OZoTQMuRpuNKOJbpL3HHwS4UAYIBNmDwLm 13wkKW38tTzU4inGH8e1hjqQuA4VEPUs0X3J/asgr4qXJNPfogPFY90G2mCPQpJSTl +FN+9jvcFq0TH4dWpVxzq7zXbPbDwpFEmR7RZQl+qDDy+ZVBFxqZo7xpzYzquwRXRs q3maT+ro4Rn4flmn48+q2qpiovLIimhwJbuNTS8lfe148AsaX1HbdbZU2fcHjiC8eq 8bbLwxhidvRdQ== From: Ard Biesheuvel To: linux-efi@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Ard Biesheuvel , Evgeniy Baskov , Borislav Petkov , Andy Lutomirski , Dave Hansen , Ingo Molnar , Peter Zijlstra , Thomas Gleixner , Alexey Khoroshilov , Peter Jones , Gerd Hoffmann , Dave Young , Mario Limonciello , Kees Cook , Tom Lendacky , "Kirill A . Shutemov" , Linus Torvalds , Joerg Roedel Subject: [PATCH v7 16/22] x86/efistub: Prefer EFI memory attributes protocol over DXE services Date: Fri, 28 Jul 2023 11:09:10 +0200 Message-Id: <20230728090916.1538550-17-ardb@kernel.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230728090916.1538550-1-ardb@kernel.org> References: <20230728090916.1538550-1-ardb@kernel.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=3324; i=ardb@kernel.org; h=from:subject; bh=2+7iwEobaM7sVn9y3ZDpX6mWLwOi48XQ2V4eIw6Xv00=; b=owGbwMvMwCFmkMcZplerG8N4Wi2JIeVw65YPyiURGQ+6Hp43STs0P11B6qDF6UVtIYaKqkd8b FyKirM6SlkYxDgYZMUUWQRm/3238/REqVrnWbIwc1iZQIYwcHEKwES0LRj+V02f+n277kqhjGRt j9y2QvZmxciAoC3ndvneSGQzFwyJZvgrJnzBQrMrs5ZxwaGNrQ+02tY8d3S9uVvsgj+//4Tgm2n 8AA== X-Developer-Key: i=ardb@kernel.org; a=openpgp; fpr=F43D03328115A198C90016883D200E9CA6329909 Precedence: bulk List-ID: X-Mailing-List: linux-efi@vger.kernel.org Currently, the EFI stub relies on DXE services in some cases to clear non-execute restrictions from page allocations that need to be executable. This is dodgy, because DXE services are not specified by UEFI but by PI, and they are not intended for consumption by OS loaders. However, no alternative existed at the time. Now, there is a new UEFI protocol that should be used instead, so if it exists, prefer it over the DXE services calls. Signed-off-by: Ard Biesheuvel --- drivers/firmware/efi/libstub/x86-stub.c | 29 ++++++++++++++------ 1 file changed, 21 insertions(+), 8 deletions(-) diff --git a/drivers/firmware/efi/libstub/x86-stub.c b/drivers/firmware/efi/libstub/x86-stub.c index 961ae3bd87058a45..efb4f5eda6784026 100644 --- a/drivers/firmware/efi/libstub/x86-stub.c +++ b/drivers/firmware/efi/libstub/x86-stub.c @@ -26,6 +26,7 @@ const efi_system_table_t *efi_system_table; const efi_dxe_services_table_t *efi_dxe_table; u32 image_offset __section(".data"); static efi_loaded_image_t *image = NULL; +static efi_memory_attribute_protocol_t *memattr; typedef union sev_memory_acceptance_protocol sev_memory_acceptance_protocol_t; union sev_memory_acceptance_protocol { @@ -233,12 +234,18 @@ void efi_adjust_memory_range_protection(unsigned long start, unsigned long rounded_start, rounded_end; unsigned long unprotect_start, unprotect_size; - if (efi_dxe_table == NULL) - return; - rounded_start = rounddown(start, EFI_PAGE_SIZE); rounded_end = roundup(start + size, EFI_PAGE_SIZE); + if (memattr != NULL) { + efi_call_proto(memattr, clear_memory_attributes, rounded_start, + rounded_end - rounded_start, EFI_MEMORY_XP); + return; + } + + if (efi_dxe_table == NULL) + return; + /* * Don't modify memory region attributes, they are * already suitable, to lower the possibility to @@ -801,6 +808,7 @@ void __noreturn efi_stub_entry(efi_handle_t handle, efi_system_table_t *sys_table_arg, struct boot_params *boot_params) { + efi_guid_t guid = EFI_MEMORY_ATTRIBUTE_PROTOCOL_GUID; unsigned long bzimage_addr = (unsigned long)startup_32; unsigned long buffer_start, buffer_end; struct setup_header *hdr = &boot_params->hdr; @@ -812,13 +820,18 @@ void __noreturn efi_stub_entry(efi_handle_t handle, if (efi_system_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE) efi_exit(handle, EFI_INVALID_PARAMETER); - efi_dxe_table = get_efi_config_table(EFI_DXE_SERVICES_TABLE_GUID); - if (efi_dxe_table && - efi_dxe_table->hdr.signature != EFI_DXE_SERVICES_TABLE_SIGNATURE) { - efi_warn("Ignoring DXE services table: invalid signature\n"); - efi_dxe_table = NULL; + if (IS_ENABLED(CONFIG_EFI_DXE_MEM_ATTRIBUTES)) { + efi_dxe_table = get_efi_config_table(EFI_DXE_SERVICES_TABLE_GUID); + if (efi_dxe_table && + efi_dxe_table->hdr.signature != EFI_DXE_SERVICES_TABLE_SIGNATURE) { + efi_warn("Ignoring DXE services table: invalid signature\n"); + efi_dxe_table = NULL; + } } + /* grab the memory attributes protocol if it exists */ + efi_bs_call(locate_protocol, &guid, NULL, (void **)&memattr); + status = efi_setup_5level_paging(); if (status != EFI_SUCCESS) { efi_err("efi_setup_5level_paging() failed!\n");