From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-11.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AC04AC433E1 for ; Fri, 22 May 2020 18:30:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9753F204EF for ; Fri, 22 May 2020 18:30:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730972AbgEVSae (ORCPT ); Fri, 22 May 2020 14:30:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35022 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730838AbgEVSaV (ORCPT ); Fri, 22 May 2020 14:30:21 -0400 Received: from Galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C6E73C08C5C0; Fri, 22 May 2020 11:30:20 -0700 (PDT) Received: from [5.158.153.53] (helo=tip-bot2.lab.linutronix.de) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1jcCQz-0002lW-FX; Fri, 22 May 2020 20:30:17 +0200 Received: from [127.0.1.1] (localhost [IPv6:::1]) by tip-bot2.lab.linutronix.de (Postfix) with ESMTP id 28E1F1C0095; Fri, 22 May 2020 20:30:17 +0200 (CEST) Date: Fri, 22 May 2020 18:30:17 -0000 From: "tip-bot2 for Lenny Szubowicz" Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: efi/urgent] efi/libstub/x86: Avoid EFI map buffer alloc in allocate_e820() Cc: Lenny Szubowicz , Ard Biesheuvel , x86 , LKML MIME-Version: 1.0 Message-ID: <159017221704.17951.4059011817062465149.tip-bot2@tip-bot2> X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the efi/urgent branch of tip: Commit-ID: fd62619598069c974739476d1851a00d665041d7 Gitweb: https://git.kernel.org/tip/fd62619598069c974739476d1851a00d665041d7 Author: Lenny Szubowicz AuthorDate: Thu, 07 May 2020 14:33:32 -04:00 Committer: Ard Biesheuvel CommitterDate: Thu, 14 May 2020 11:11:18 +02:00 efi/libstub/x86: Avoid EFI map buffer alloc in allocate_e820() In allocate_e820(), call the EFI get_memory_map() service directly instead of indirectly via efi_get_memory_map(). This avoids allocation of a buffer and return of the full EFI memory map, which is not needed here and would otherwise need to be freed. Routine allocate_e820() only needs to know how many EFI memory descriptors there are in the map to allocate an adequately sized e820ext buffer, if it's needed. Note that since efi_get_memory_map() returns a memory map buffer sized with extra headroom, allocate_e820() now needs to explicitly factor that into the e820ext size calculation. Signed-off-by: Lenny Szubowicz Suggested-by: Ard Biesheuvel Signed-off-by: Ard Biesheuvel --- drivers/firmware/efi/libstub/efistub.h | 13 +++++++++++++- drivers/firmware/efi/libstub/mem.c | 2 +-- drivers/firmware/efi/libstub/x86-stub.c | 24 +++++++++--------------- 3 files changed, 22 insertions(+), 17 deletions(-) diff --git a/drivers/firmware/efi/libstub/efistub.h b/drivers/firmware/efi/libstub/efistub.h index 67d2694..6294399 100644 --- a/drivers/firmware/efi/libstub/efistub.h +++ b/drivers/firmware/efi/libstub/efistub.h @@ -92,6 +92,19 @@ extern __pure efi_system_table_t *efi_system_table(void); #define EFI_LOCATE_BY_REGISTER_NOTIFY 1 #define EFI_LOCATE_BY_PROTOCOL 2 +/* + * An efi_boot_memmap is used by efi_get_memory_map() to return the + * EFI memory map in a dynamically allocated buffer. + * + * The buffer allocated for the EFI memory map includes extra room for + * a minimum of EFI_MMAP_NR_SLACK_SLOTS additional EFI memory descriptors. + * This facilitates the reuse of the EFI memory map buffer when a second + * call to ExitBootServices() is needed because of intervening changes to + * the EFI memory map. Other related structures, e.g. x86 e820ext, need + * to factor in this headroom requirement as well. + */ +#define EFI_MMAP_NR_SLACK_SLOTS 8 + struct efi_boot_memmap { efi_memory_desc_t **map; unsigned long *map_size; diff --git a/drivers/firmware/efi/libstub/mem.c b/drivers/firmware/efi/libstub/mem.c index 869a79c..09f4fa0 100644 --- a/drivers/firmware/efi/libstub/mem.c +++ b/drivers/firmware/efi/libstub/mem.c @@ -5,8 +5,6 @@ #include "efistub.h" -#define EFI_MMAP_NR_SLACK_SLOTS 8 - static inline bool mmap_has_headroom(unsigned long buff_size, unsigned long map_size, unsigned long desc_size) diff --git a/drivers/firmware/efi/libstub/x86-stub.c b/drivers/firmware/efi/libstub/x86-stub.c index 05ccb22..f0339b5 100644 --- a/drivers/firmware/efi/libstub/x86-stub.c +++ b/drivers/firmware/efi/libstub/x86-stub.c @@ -606,24 +606,18 @@ static efi_status_t allocate_e820(struct boot_params *params, struct setup_data **e820ext, u32 *e820ext_size) { - unsigned long map_size, desc_size, buff_size; - struct efi_boot_memmap boot_map; - efi_memory_desc_t *map; + unsigned long map_size, desc_size, map_key; efi_status_t status; - __u32 nr_desc; + __u32 nr_desc, desc_version; - boot_map.map = ↦ - boot_map.map_size = &map_size; - boot_map.desc_size = &desc_size; - boot_map.desc_ver = NULL; - boot_map.key_ptr = NULL; - boot_map.buff_size = &buff_size; + /* Only need the size of the mem map and size of each mem descriptor */ + map_size = 0; + status = efi_bs_call(get_memory_map, &map_size, NULL, &map_key, + &desc_size, &desc_version); + if (status != EFI_BUFFER_TOO_SMALL) + return (status != EFI_SUCCESS) ? status : EFI_UNSUPPORTED; - status = efi_get_memory_map(&boot_map); - if (status != EFI_SUCCESS) - return status; - - nr_desc = buff_size / desc_size; + nr_desc = map_size / desc_size + EFI_MMAP_NR_SLACK_SLOTS; if (nr_desc > ARRAY_SIZE(params->e820_table)) { u32 nr_e820ext = nr_desc - ARRAY_SIZE(params->e820_table);