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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 04C05C4332F for ; Mon, 21 Nov 2022 16:58:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229476AbiKUQ6d (ORCPT ); Mon, 21 Nov 2022 11:58:33 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51082 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229460AbiKUQ6d (ORCPT ); Mon, 21 Nov 2022 11:58:33 -0500 Received: from out2.migadu.com (out2.migadu.com [IPv6:2001:41d0:2:aacc::]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4D800E1C for ; Mon, 21 Nov 2022 08:58:31 -0800 (PST) Date: Tue, 22 Nov 2022 00:58:01 +0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1669049909; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=lEB5sh1/jYLycgzf6hWVQ3EeKLUvTYuUqdOi39E1eA0=; b=jiGbQ4uJNZ21+fNIJjIv+B2mA3lsqr/SPyq3nARdrS1nQvKMIcLo95l1g/jNScRdSx6eq9 bGN6ihBFqSiIIP5jbIau4lq0lJzNSX4XUpwrojxf5CUWggmCbNdgiRfKqmXPBCyObzWn9R rPcYHVaQ+XWiuoqpCXgDykipNJHSwG0= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Wu XiangCheng To: Yanteng Si Cc: chenhuacai@kernel.org, corbet@lwn.net, alexs@kernel.org, seakeel@gmail.com, kernel@xen0n.name, jiaxun.yang@flygoat.com, linux-doc@vger.kernel.org, loongarch@lists.linux.dev, siyanteng01@gmail.com, Xiaotian Wu , Yun Liu Subject: Re: [PATCH v1 1/2] docs/LoongArch: Add boot image header Message-ID: References: <08df007c7488b88ff5400bef6183f9cc68d87616.1669032230.git.siyanteng@loongson.cn> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <08df007c7488b88ff5400bef6183f9cc68d87616.1669032230.git.siyanteng@loongson.cn> X-Migadu-Flow: FLOW_OUT Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org +Cc: Yun Liu 2022-11-21 (一) 20:16:30 +0800 Yanteng Si 曰： > Describes the meaning and value of the image header field. > > Suggested-by: Xiaotian Wu > Signed-off-by: Yanteng Si > --- > Documentation/loongarch/boot-image-header.rst | 76 +++++++++++++++++++ > Documentation/loongarch/index.rst | 1 + > 2 files changed, 77 insertions(+) > create mode 100644 Documentation/loongarch/boot-image-header.rst > > diff --git a/Documentation/loongarch/boot-image-header.rst b/Documentation/loongarch/boot-image-header.rst > new file mode 100644 > index 000000000000..92a953a6f2e6 > --- /dev/null > +++ b/Documentation/loongarch/boot-image-header.rst > @@ -0,0 +1,76 @@ > +.. SPDX-License-Identifier: GPL-2.0 > + > +==================================== > +Boot image header in LoongArch Linux > +==================================== > + > +:Author: Yanteng Si > +:Date: 18 Nov 2022 > + > +This document only describes the boot image header details for > +LoongArch Linux. > + > +The following 64-byte header is present in decompressed Linux > +kernel image:: > + > + u32 MZ_MAGIC /* "MZ", MS-DOS header */ > + u32 res0 = 0 /* reserved */ > + u64 kernel_entry /* Kernel entry point */ > + u64 _end - _text /* Kernel image effective size */ > + u64 0 /* Kernel image load offset from start of RAM */ > + u64 res1 = 0 /* reserved */ > + u64 res2 = 0 /* reserved */ > + u64 res3 = 0 /* reserved */ > + u32 res4 = 0 /* reserved */ > + u32 pe_header - _head /* Offset to the PE header */ > + Any code related need to be linked here? > + > +Header notes > +============ > + > +Currently, LoongArch has removed the "magic" field. > + > +According to the EFI specification, the PE/COFF image file header is > +required at the beginning of the kernel image; the LoongArch kernel > +supports the EFI stub, so the first two bytes of the kernel image header > +are "MZ" magic characters, and 0x3c should point to the rest of the > +PE/COFF file header, between which The kernel entry point, image > +effectivesize, and image load offset layout are as follows:: > + > + +-----------------------------------------------+ > + 0x0: | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | > + +-----------------------------------------------+ > + 0x8: | MZ_MAGIC | res0 | > + +-----------------------------------------------+ > + 0x10: | kernel_entry | > + +-----------------------------------------------+ > + 0x18: | _end - _text | > + +-----------------------------------------------+ > + 0x20: | 0 | > + +-----------------------------------------------+ > + 0x28: | res1 | > + +-----------------------------------------------+ > + 0x30: | res2 | > + +-----------------------------------------------+ > + 0x38: | res3 | > + +-----------------------------------------------+ > + 0x40: | res14 | PE header | > + +-----------------------------------------------+ > + emmm, this figure... So MZ_MAGIC start from 0x08 ? Or 0 1 2 3 4 5 6 7 +-----------------------+-----------------------+ 0x00 | MZ_MAGIC | res0 | +-----------------------+-----------------------+ 0x08 | kernel_entry | +-----------------------------------------------+ 0x10 | _end - _text | +-----------------------------------------------+ 0x18 | 0 | +-----------------------------------------------+ 0x20 | res1 | +-----------------------------------------------+ 0x28 | res2 | +-----------------------------------------------+ 0x30 | res3 | +-----------------------+-----------------------+ 0x38 | res14 | PE header | +-----------------------+-----------------------+ If the figure is too difficult to draw, a simple table can also be used to instead. Offset Name Size Note ... > + > +All bit fields are in little endian: > + > + - MZ: Effective length of 2 bytes; > + > + - kernel entry point: leaving 6 bytes blank in front, starting > + from 0x8, with a effective length of 8 bytes; > + > + - kernel image effective size: Immediately following the kernel > + entry point, with a effective length of 8 bytes, this field is > + required for the bootloader; > + > + - kernel image load offset: Immediately following the kernel > + image effective size, with a effective length of 8 bytes; > + > + - Offset to the PE header: leaving 28 bytes blank in front, > + starting from 0x3c, with a effective length of 4 bytes. > diff --git a/Documentation/loongarch/index.rst b/Documentation/loongarch/index.rst > index aaba648db907..97419821adf9 100644 > --- a/Documentation/loongarch/index.rst > +++ b/Documentation/loongarch/index.rst > @@ -10,6 +10,7 @@ LoongArch Architecture > > introduction > irq-chip-model > + boot-image-header > > features > > -- > 2.31.1 > -- Wu XiangCheng 0x32684A40BCA7AEA7