From patchwork Wed Feb 8 11:55:39 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ard Biesheuvel X-Patchwork-Id: 93615 Delivered-To: patch@linaro.org Received: by 10.140.20.99 with SMTP id 90csp2648888qgi; Wed, 8 Feb 2017 04:05:18 -0800 (PST) X-Received: by 10.84.225.148 with SMTP id u20mr32865615plj.93.1486555518711; Wed, 08 Feb 2017 04:05:18 -0800 (PST) Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id 72si6933694pfj.150.2017.02.08.04.05.18; Wed, 08 Feb 2017 04:05:18 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-efi-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=neutral (body hash did not verify) header.i=@linaro.org; spf=pass (google.com: best guess record for domain of linux-efi-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-efi-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=linaro.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932378AbdBHME5 (ORCPT + 2 others); Wed, 8 Feb 2017 07:04:57 -0500 Received: from mail-wr0-f172.google.com ([209.85.128.172]:34308 "EHLO mail-wr0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932289AbdBHME4 (ORCPT ); Wed, 8 Feb 2017 07:04:56 -0500 Received: by mail-wr0-f172.google.com with SMTP id o16so59330046wra.1 for ; Wed, 08 Feb 2017 04:04:50 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=SrLACJRtqeqes8x8zbhltXJF5VJs3kD4d+gHL4SAfIg=; b=IsHNNrdZoUx3LMTpmQRZaxhgiLlvNe/1ueD27be3UjfjKh7EqKykVM4Ryevui9Gt6Z dSHAUcc1h0zdgVfRcE49O5SmFgHrzl92SM623N5vOAVLNlmbWLuKvOtxkJ6b3XfbuKA/ co6P/YsFYRDxvfqZHY1pwdINGY3/ubJQPcBmg= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=SrLACJRtqeqes8x8zbhltXJF5VJs3kD4d+gHL4SAfIg=; b=HRInunMfmo6H20Z52k6iLH8y7XnxgvneP4jSvpgHIO9vbCNhZfNN0n0V+uoigiu0Go ihGASBIzeE55bxd/HM6pcPaKL66uYnlPKhFoc7NR9p3KiGpNXET9cMjj9h1GWnlcZ+Q9 XJpBoHEwFP0FvzAXJtCI4i0e34YdcOhXRWK6gGnbTXuWu+JTWTb/ReeJcKdmeYaZUWqZ erk3vWS9RU0DGhQ0QNWV2N5EwWbu1X2JSLgk0ieZqdafiw5uqV2+aiux0RfH/WGXv1FQ bcVrfodR2Q0GK5xxYeS61FwCWySVoHYmy7bjhZypNwba4pYYWD5I6Bja8knjtGM0qtoi Tq7w== X-Gm-Message-State: AIkVDXL1valT7Eq6IK2gdq2ncSekuZ1JnsZvDgSISdppF2GTTtuJL8rhnW9u9K4fdoLMTo9q X-Received: by 10.223.133.131 with SMTP id 3mr18743211wrt.161.1486554978965; Wed, 08 Feb 2017 03:56:18 -0800 (PST) Received: from localhost.localdomain ([160.169.163.122]) by smtp.gmail.com with ESMTPSA id 123sm2974815wml.6.2017.02.08.03.56.16 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Wed, 08 Feb 2017 03:56:18 -0800 (PST) From: Ard Biesheuvel To: linux-efi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, mark.rutland@arm.com, leif.lindholm@linaro.org Cc: catalin.marinas@arm.com, linux@armlinux.org.uk, kernel-hardening@lists.openwall.com, labbott@fedoraproject.org, Ard Biesheuvel Subject: [PATCH v2 06/14] arm64: efi: remove pointless dummy .reloc section Date: Wed, 8 Feb 2017 11:55:39 +0000 Message-Id: <1486554947-3964-7-git-send-email-ard.biesheuvel@linaro.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1486554947-3964-1-git-send-email-ard.biesheuvel@linaro.org> References: <1486554947-3964-1-git-send-email-ard.biesheuvel@linaro.org> Sender: linux-efi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-efi@vger.kernel.org The kernel's EFI PE/COFF header contains a dummy .reloc section, and an explanatory comment that claims that this is required for the EFI application loader to accept the Image as a relocatable image (i.e., one that can be loaded at any offset and fixed up in place) This was inherited from the x86 implementation, which has elaborate host tooling to mangle the PE/COFF header post-link time, and which populates the .reloc section with a single dummy base relocation. On ARM, no such tooling exists, and the .reloc section remains empty, and is never even exposed via the BaseRelocationTable directory entry, which is where the PE/COFF loader looks for it. The PE/COFF spec is unclear about relocatable images that do not require any fixups, but the EDK2 implementation, which is the de facto reference for PE/COFF in the UEFI space, clearly does not care, and explicitly mentions (in a comment) that relocatable images with no base relocations are perfectly fine, as long as they don't have the RELOCS_STRIPPED attribute set (which is not the case for our PE/COFF image) So simply remove the .reloc section altogether. Acked-by: Mark Rutland Acked-by: Peter Jones Signed-off-by: Ard Biesheuvel --- arch/arm64/kernel/efi-header.S | 22 +------------------- 1 file changed, 1 insertion(+), 21 deletions(-) -- 2.7.4 -- To unsubscribe from this list: send the line "unsubscribe linux-efi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/arch/arm64/kernel/efi-header.S b/arch/arm64/kernel/efi-header.S index 515624bbfcd0..8786d58af2df 100644 --- a/arch/arm64/kernel/efi-header.S +++ b/arch/arm64/kernel/efi-header.S @@ -12,7 +12,7 @@ .short 0 coff_header: .short 0xaa64 // AArch64 - .short 2 // nr_sections + .short 1 // nr_sections .long 0 // TimeDateStamp .long 0 // PointerToSymbolTable .long 0 // NumberOfSymbols @@ -71,26 +71,6 @@ extra_header_fields: // Section table section_table: - - /* - * The EFI application loader requires a relocation section - * because EFI applications must be relocatable. This is a - * dummy section as far as we are concerned. - */ - .ascii ".reloc" - .byte 0 - .byte 0 // end of 0 padding of section name - .long 0 - .long 0 - .long 0 // SizeOfRawData - .long 0 // PointerToRawData - .long 0 // PointerToRelocations - .long 0 // PointerToLineNumbers - .short 0 // NumberOfRelocations - .short 0 // NumberOfLineNumbers - .long 0x42000040 // Characteristics (section flags) - - .ascii ".text" .byte 0 .byte 0