From patchwork Sun May 17 12:57:50 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ard Biesheuvel X-Patchwork-Id: 11554147 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 9C0C614B7 for ; Sun, 17 May 2020 12:58:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7BC0B20809 for ; Sun, 17 May 2020 12:58:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589720326; bh=5tXL+YjtmxVs2yaNSEFQ3R9gk1JxmZK5tELvxsPiRaw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=WzpIUY7aaFaBivYsP9e/7EARfufOEnHgXEGABEgaydcGukfgd9ml2Qu85/Urg8y+S wjnXYm4CBnOC/djfIgV3dyWZU2IykyZSBXNLBSWdvTHY4LV0KTjX3hHFcC+s3rVQ6g tPHONJTPAtENrzgiNpsDO9l3IUzivpUHTQKw+os0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728040AbgEQM6p (ORCPT ); Sun, 17 May 2020 08:58:45 -0400 Received: from mail.kernel.org ([198.145.29.99]:51688 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728035AbgEQM6p (ORCPT ); Sun, 17 May 2020 08:58:45 -0400 Received: from e123331-lin.nice.arm.com (amontpellier-657-1-18-247.w109-210.abo.wanadoo.fr [109.210.65.247]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 4359D204EC; Sun, 17 May 2020 12:58:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589720323; bh=5tXL+YjtmxVs2yaNSEFQ3R9gk1JxmZK5tELvxsPiRaw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=WKOE2jgf3mmUgNcnc03VCWp0QnSJ3zH4qHJXG7/KwC8HQi0nBluxZ0LDnfVw1Xfak tgkQYmt0yoWOvOeG2rzjt+BfpUo/89IVTH07R4qkw1ZVOfGcacS8NF5jzYTxohJin2 H6AUm8BeylyWB5mZkdEm1iS3VKNb1s/L6FTjta34= From: Ard Biesheuvel To: linux-efi@vger.kernel.org, Ingo Molnar , Thomas Gleixner Cc: Ard Biesheuvel , linux-kernel@vger.kernel.org, Arvind Sankar , Benjamin Thiel , Borislav Petkov , Dave Young , Heinrich Schuchardt , Javier Martinez Canillas , Jerry Snitselaar , Lenny Szubowicz , linux-acpi@vger.kernel.org, Loic Yhuel , Matthew Garrett , Mike Lothian , Punit Agrawal Subject: [PATCH 3/7] efi/libstub/x86: Avoid EFI map buffer alloc in allocate_e820() Date: Sun, 17 May 2020 14:57:50 +0200 Message-Id: <20200517125754.8934-4-ardb@kernel.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200517125754.8934-1-ardb@kernel.org> References: <20200517125754.8934-1-ardb@kernel.org> Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org From: Lenny Szubowicz 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 67d26949fd26..62943992f02f 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 869a79c8946f..09f4fa01914e 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 05ccb229fb45..f0339b5d3658 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);