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 X-Spam-Level: X-Spam-Status: No, score=-14.3 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_IN_DEF_DKIM_WL autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A9EB1C433DF for ; Wed, 17 Jun 2020 21:27:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 88F4A20FC3 for ; Wed, 17 Jun 2020 21:27:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="iS5qr4j2" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726940AbgFQV1L (ORCPT ); Wed, 17 Jun 2020 17:27:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39296 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726835AbgFQV1K (ORCPT ); Wed, 17 Jun 2020 17:27:10 -0400 Received: from mail-pg1-x543.google.com (mail-pg1-x543.google.com [IPv6:2607:f8b0:4864:20::543]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A0C98C0613ED for ; Wed, 17 Jun 2020 14:27:09 -0700 (PDT) Received: by mail-pg1-x543.google.com with SMTP id t7so1911269pgt.3 for ; Wed, 17 Jun 2020 14:27:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:content-transfer-encoding:in-reply-to; bh=2nweBLFqBZAQdpGCmNWKSAsTxcg83keuNMEngTx9xf4=; b=iS5qr4j2jYfHzGGbhesyIJUTnsGRa9IuN+Jl4fPLDGmN8Gke6H88DdYjKDHwrWfEf1 /juIa85YnrqZffvIfhiCjYqxxxAIkDfxVWShz0uKUrVPf/7IsN76HMeksxs//UhpzeGK TmNk1sEkVyNbwZ4I2Sqdw7gfzZLCpugvbg4r0zmyFHpo869eLEJeZyWSPsqT8yv0K96r w9zTU5DHZj70u+cUsqzcVJx3Bc3SZYG/SBfcndzrRQhv6CuMwHA9NhaI8lss21I1BOgV RJw0PmOazu4zptp4cPhneUrJXlLBGHLgvAQLt5xApO6v/359aVgyNfiQDi39AXVKNSWW LZxw== 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:cc:subject:message-id:references :mime-version:content-disposition:content-transfer-encoding :in-reply-to; bh=2nweBLFqBZAQdpGCmNWKSAsTxcg83keuNMEngTx9xf4=; b=tJsnxVBKiaghGhoVEhbObt5reFVkQvdyg9QWIjG+7WinQMNZgP3n0fZfAWGHUb1lkw HSAWPwr5bFd0po16c4l0MaTbaZ+Ua17Bpgogt4ierdZ39d92wZsjJppAYxrraq9jwH17 8/cJGhiAnU8rJ4PrvUXmybTVvb9a4SSFxZzQS0Sd+KwRxX0W9lN6JRalBClIP9x8YiWj ZgFiWV+MYQLQUf8GzaecCs+StQZ/XiGbwBGF1zrvY44/JfaQ2ZwRV3661N933WXYftxM nMUyykAhgsVZ/9aaGwfikSgNSFiaCNq9DsiALrkW/qPwZdaUwuCgIHdG/igZWHiKZd56 EEaQ== X-Gm-Message-State: AOAM53022eKojfoK1azStqb7SVyryf4UXaHmqoYW/WEDowkJKRS+6k3O c9SQO4heb8uO0tptXQBvKsyHbg== X-Google-Smtp-Source: ABdhPJxYyUBYE6IphPAEyvDdCsWndemGsGv25bBXi+wuKSeSYT+KvkLCOsnLwdE99qal0DA1+G+XFg== X-Received: by 2002:a63:5307:: with SMTP id h7mr702582pgb.28.1592429228594; Wed, 17 Jun 2020 14:27:08 -0700 (PDT) Received: from google.com ([2620:15c:2ce:0:9efe:9f1:9267:2b27]) by smtp.gmail.com with ESMTPSA id m4sm644574pgp.32.2020.06.17.14.27.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 17 Jun 2020 14:27:07 -0700 (PDT) Date: Wed, 17 Jun 2020 14:27:05 -0700 From: =?utf-8?B?RsSBbmctcnXDrCBTw7JuZw==?= To: Nick Desaulniers Cc: Arnd Bergmann , clang-built-linux@googlegroups.com, Kees Cook , stable@vger.kernel.org, Jian Cai , Luis Lozano , Manoj Gupta , linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] vmlinux.lds: consider .text.{hot|unlikely}.* part of .text too Message-ID: <20200617212705.tq2q6bi446gydymo@google.com> References: <20200617210613.95432-1-ndesaulniers@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20200617210613.95432-1-ndesaulniers@google.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2020-06-17, Nick Desaulniers wrote: >ld.bfd's internal linker script considers .text.hot AND .text.hot.* to >be part of .text, as well as .text.unlikely and .text.unlikely.*. >ld.lld will produce .text.hot.*/.text.unlikely.* sections. Correction to this sentence. lld is not relevant here. -ffunction-sections combined with profile-guided optimization can produce .text.hot.* .text.unlikely.* sections. Newer clang may produce .text.hot. .text.unlikely. (without suffix, but with a trailing dot) when -fno-unique-section-names is specified, as an optimization to make .strtab smaller. We've already seen that GCC can place main in .text.startup without -ffunction-sections. There may be other non -ffunction-sections cases for .text.hot.* or .text.unlikely.*. So it is definitely a good idea to be more specific even if we don't care about -ffunction-sections for now. >Make sure to group these together. Otherwise these orphan sections may >be placed outside of the the _stext/_etext boundaries. > >Cc: stable@vger.kernel.org >Link: https://sourceware.org/git/?p=binutils-gdb.git;a=commitdiff;h=add44f8d5c5c05e08b11e033127a744d61c26aee >Link: https://sourceware.org/git/?p=binutils-gdb.git;a=commitdiff;h=1de778ed23ce7492c523d5850c6c6dbb34152655 >Link: https://reviews.llvm.org/D79600 >Reported-by: Jian Cai >Debugged-by: Luis Lozano >Suggested-by: Fāng-ruì Sòng >Tested-by: Luis Lozano >Tested-by: Manoj Gupta >Signed-off-by: Nick Desaulniers >--- > include/asm-generic/vmlinux.lds.h | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > >diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h >index d7c7c7f36c4a..fe5aaef169e3 100644 >--- a/include/asm-generic/vmlinux.lds.h >+++ b/include/asm-generic/vmlinux.lds.h >@@ -560,7 +560,9 @@ > */ > #define TEXT_TEXT \ > ALIGN_FUNCTION(); \ >- *(.text.hot TEXT_MAIN .text.fixup .text.unlikely) \ >+ *(.text.hot .text.hot.*) \ >+ *(TEXT_MAIN .text.fixup) \ >+ *(.text.unlikely .text.unlikely.*) \ > NOINSTR_TEXT \ > *(.text..refcount) \ > *(.ref.text) \ >-- >2.27.0.290.gba653c62da-goog >