From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp.gentoo.org (smtp.gentoo.org [140.211.166.183]) by sourceware.org (Postfix) with ESMTP id CADFB386182B for ; Tue, 20 Apr 2021 13:19:25 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org CADFB386182B Received: from vapier (localhost [127.0.0.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.gentoo.org (Postfix) with ESMTPS id 9B8B7335D0A; Tue, 20 Apr 2021 13:19:24 +0000 (UTC) Date: Tue, 20 Apr 2021 09:19:23 -0400 From: Mike Frysinger To: Peng Yu Cc: Szabolcs Nagy , libc-help Subject: Re: Best reference for understanding ELF format Message-ID: Mail-Followup-To: Peng Yu , Szabolcs Nagy , libc-help References: <20210419072902.GB9028@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: X-Spam-Status: No, score=-4.4 required=5.0 tests=BAYES_00, KAM_DMARC_STATUS, KAM_SHORT, RCVD_IN_MSPIKE_H3, RCVD_IN_MSPIKE_WL, SPF_HELO_PASS, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-help@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-help mailing list List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 20 Apr 2021 13:19:36 -0000 On 19 Apr 2021 20:58, Peng Yu via Libc-help wrote: > On 4/19/21, Szabolcs Nagy wrote: > > The 04/17/2021 07:31, Peng Yu via Libc-help wrote: > >> That is a book. By definition, a book will not be complete since a > >> book is not written for completeness? > >> > >> For the best reference (as "reference" may have muliple meanings maybe > >> I should use the word "spec" to avoid ambiguity), I found the > >> following two documents. One is for 32-bit, the other is for 64-bit. > >> Are they the most current ones? Other there any other documents that > >> cover the things missed by them? > >> > >> https://refspecs.linuxfoundation.org/elf/elf.pdf > >> https://www.uclibc.org/docs/elf-64-gen.pdf > > > > elf spec is part of the system v abi document. > > the generic part is in > > http://www.sco.com/developers/gabi/ > > the processor specific part is published separately by > > whoever does the tooling for the particular processor. > > > > (all this can be found out by 5 minute research on wikipedia) > > > > but since you asked for easy-to-follow and for > > understanding elf i think the book is better. > > Updated is also needed. An outdated reference is not preferred even it > is easy to follow. pretty much all the content in the book is still relevant. the fact that it doesn't cover the latest ELF extensions doesn't mean that the fundamentals are no longer relevant. > I found this book is quite outdated. It does not explain the current > gcc and clang. gcc & clang don't produce ELFs. so, at best, they'd be mentioned in passing even in the latest docs. > For example, gcc mostly use RELA instead of REL. But this book says this. gcc doesn't generate relocations. also "mostly" is a bit skewed. it depends on the architecture. > So a better reference in terms of all three aspects that I mentioned is needed. you need to learn to walk before you can hope to run. -mike