From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pj1-f66.google.com (mail-pj1-f66.google.com [209.85.216.66]) by sourceware.org (Postfix) with ESMTPS id 757D4385B836 for ; Tue, 31 Mar 2020 06:17:54 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 757D4385B836 Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=maskray.me Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=emacsray@gmail.com Received: by mail-pj1-f66.google.com with SMTP id q16so697611pje.1 for ; Mon, 30 Mar 2020 23:17:54 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=hURuQtLyLG12eYHEyDPlJPXRQa2CazI5zMdl1pWc1CM=; b=Js4lkwvl15g0+Y5jUqslnd+ImEP9FSn+uEKlAKvZ4psV5aAEnTFrH0Q9uxFM3dwplz aNBool1FtE/bNZTo4BEQAFFim8+PgNK0HaqPz7TRFPKJjEU0Xekr0ZZ7SQLC7F4KV4ou gNIGUloAcztLSshQFV/qGaHfPW/dRlOFwwcVpzf+YlmwbqcfoJ/RC+odF/W+ZPus/zFx bioZSQhn5iOhAZplvfLQu+1yEnFB+roBJ58cmuwS4t1BkSZ1WosqzSbOrv+zDzTwBL8i NaLkYzOh8MufWKe0i9s33kYGYTtWaFYxIpFI/RLudeNwQWGxLHUMPQqDx5soUtQtH6Ur a/nQ== X-Gm-Message-State: AGi0PuZDVjk86HYZiJY6DS9ZeHWP0QWdC3Fvk2b/5Z/TEWEavCQbzGro s6DKKbU58Mu1eSJE+yullGmVqZRU X-Google-Smtp-Source: APiQypKswHgz/Y3/0pkMpJOcaknITbCmv42YH/V6owTdMlReXGLl5/OIAXAVcrUM23t3dwDTHtKW1w== X-Received: by 2002:a17:90a:7785:: with SMTP id v5mr1894879pjk.120.1585635473349; Mon, 30 Mar 2020 23:17:53 -0700 (PDT) Received: from localhost ([2601:647:4b01:ae80::51fb]) by smtp.gmail.com with ESMTPSA id c11sm11891693pfc.216.2020.03.30.23.17.52 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 30 Mar 2020 23:17:52 -0700 (PDT) Date: Mon, 30 Mar 2020 23:17:51 -0700 From: Fangrui Song To: "H.J. Lu via Binutils" Subject: Re: [PATCH] x86: Only allow S - A relocations against absolute symbol Message-ID: <20200331061751.qjcv7z5z4rbyu45l@gmail.com> References: <20200331044350.808132-1-hjl.tools@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <20200331044350.808132-1-hjl.tools@gmail.com> X-Spam-Status: No, score=-2.7 required=5.0 tests=BAYES_00, FREEMAIL_FORGED_FROMDOMAIN, FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS, KAM_DMARC_STATUS, KAM_INFOUSMEBIZ, RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H3, RCVD_IN_MSPIKE_WL, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=no autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: binutils@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Binutils mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 31 Mar 2020 06:17:55 -0000 On 2020-03-30, H.J. Lu via Binutils wrote: >Since value of non-preemptible absolute symbol (SHN_ABS) won't change, >only S - A relocations against non-preemptible absolute symbol are >allowed in PIE and shared library. Thanks for the patch. At some point we should define some generic relocation categories (https://reviews.llvm.org/rL266158). For example, - R_ABS: R_X86_64_8, R_X86_64_16, R_X86_64_32, R_X86_64_64 R_AARCH64_ABS16, R_AARCH64_ABS32, R_AARCH64_ABS64 R_PPC64_ADDR16, R_PPC64_ADDR16_DS, R_PPC64_ADDR16_HA, ... - R_PCREL: R_X86_64_PC8, R_X86_64_PC16, R_X86_64_PC32, R_X86_64_PC64 R_AARCH64_PREL16, R_AARCH64_PREL32, R_AARCH64_PREL64 - R_PLT_PCREL: R_X86_64_PLT32, R_AARCH64_CALL26 - R_GOT_PCREL: R_X86_64_GOTPCREL, R_X86_64_GOTPCRELX Define a property is_preemptible as a more appropriate level of abstraction for GENERATE_DYNAMIC_RELOCATION_P and some use cases of bfd_link_pic and bfd_link_executable...