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=-11.6 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=no 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 69E6CC433E0 for ; Thu, 25 Jun 2020 16:22:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2F04A20CC7 for ; Thu, 25 Jun 2020 16:22:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="XvqTcKvU" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2403780AbgFYQWf (ORCPT ); Thu, 25 Jun 2020 12:22:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36276 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390708AbgFYQWe (ORCPT ); Thu, 25 Jun 2020 12:22:34 -0400 Received: from mail-pg1-x544.google.com (mail-pg1-x544.google.com [IPv6:2607:f8b0:4864:20::544]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A967DC08C5DB for ; Thu, 25 Jun 2020 09:22:34 -0700 (PDT) Received: by mail-pg1-x544.google.com with SMTP id t6so3525958pgq.1 for ; Thu, 25 Jun 2020 09:22:34 -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:in-reply-to; bh=cYEaM8fKpZG71PCkfHkApRmPtCwvXrrY+JocHC3nIv8=; b=XvqTcKvUnBqjH+Xq2/BDnD76lMTzDE39N73VPsal3e7jDR5L9CqPzEwi/HtJXxg5pZ sSViKozmxlxfRjR5junnpvtTtyW6G2rRQEW8ZFvCQk6aCeqvQ+zuO9yimSN9sFS7QooW PvXgArAb+SfCZcIY+Pqu9KdLFcAqo8UvqBCXGiy9t48Z69ZF5FReGe2odlppsG/6UARl Mdd0bQaWJWxZe0j9OL67jRPrRKjRhuCt16S32a8eOmCrvrHTXERopZ1dh0M2Ua2NwCSI Ek6M040jALm4P02V4qkx9xuhsfQb+UTvzenYTCIy4JIByKPSb7KkGeYN6II1dO0BKO5s 5Xmw== 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:in-reply-to; bh=cYEaM8fKpZG71PCkfHkApRmPtCwvXrrY+JocHC3nIv8=; b=kjK9WPQk8EG2JQBdI6q3rv8YimTCm0P8TXv6LMncTyHYqzFHhC7Ag0E4GUReuJXTBB KRMZfrFz8lCcW7xE0nyNm3sqdU3JGdOJWQbwvVube1eU+rHJChUM2qY1HaXFoQAKb4Wr WVsxRVtZ8zKZ99mdBBJDllAUxXXqVL1FwdpOAhZ1l7I7+LF5i8l++3VfWgMgu7VtZkS7 6d7X6FZ7HrQSki/jGqU6aBUbPxHJzcauUwf67tis5/NpF4nbtAzK2aMvXwspkbuYdWEy cphpxzn3qdQCsxTxDaUizrWQQepmmQRa0XqqCS/LQBS0OxEOUyoeBbYgtX6x2ecgI74Y pNWw== X-Gm-Message-State: AOAM5309RDMPSkwY5ArZLKZZ6Cb3MCi40BIkQJcIlBi2sImUIUmyiZin xQu66xbZfq5SDrMlYETKse+gtQ== X-Google-Smtp-Source: ABdhPJyBu5UBNmD93hBhA1nGG7iT9G95iHuvLnDzS07QCS69km8HMKCSBSO/u5bBKV8BF6Gd+7YLGw== X-Received: by 2002:a63:7313:: with SMTP id o19mr27664372pgc.307.1593102153849; Thu, 25 Jun 2020 09:22:33 -0700 (PDT) Received: from google.com ([2620:15c:201:2:ce90:ab18:83b0:619]) by smtp.gmail.com with ESMTPSA id 7sm10151225pgh.80.2020.06.25.09.22.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 25 Jun 2020 09:22:32 -0700 (PDT) Date: Thu, 25 Jun 2020 09:22:26 -0700 From: Sami Tolvanen To: Peter Zijlstra Cc: Masahiro Yamada , Will Deacon , Greg Kroah-Hartman , "Paul E. McKenney" , Kees Cook , Nick Desaulniers , clang-built-linux@googlegroups.com, kernel-hardening@lists.openwall.com, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, x86@kernel.org Subject: Re: [PATCH 05/22] kbuild: lto: postpone objtool Message-ID: <20200625162226.GC173089@google.com> References: <20200624203200.78870-1-samitolvanen@google.com> <20200624203200.78870-6-samitolvanen@google.com> <20200624211908.GT4817@hirez.programming.kicks-ass.net> <20200624214925.GB120457@google.com> <20200625074716.GX4817@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200625074716.GX4817@hirez.programming.kicks-ass.net> Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Thu, Jun 25, 2020 at 09:47:16AM +0200, Peter Zijlstra wrote: > On Wed, Jun 24, 2020 at 02:49:25PM -0700, Sami Tolvanen wrote: > > On Wed, Jun 24, 2020 at 11:19:08PM +0200, Peter Zijlstra wrote: > > > On Wed, Jun 24, 2020 at 01:31:43PM -0700, Sami Tolvanen wrote: > > > > diff --git a/include/linux/compiler.h b/include/linux/compiler.h > > > > index 30827f82ad62..12b115152532 100644 > > > > --- a/include/linux/compiler.h > > > > +++ b/include/linux/compiler.h > > > > @@ -120,7 +120,7 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val, > > > > /* Annotate a C jump table to allow objtool to follow the code flow */ > > > > #define __annotate_jump_table __section(.rodata..c_jump_table) > > > > > > > > -#ifdef CONFIG_DEBUG_ENTRY > > > > +#if defined(CONFIG_DEBUG_ENTRY) || defined(CONFIG_LTO_CLANG) > > > > /* Begin/end of an instrumentation safe region */ > > > > #define instrumentation_begin() ({ \ > > > > asm volatile("%c0:\n\t" \ > > > > > > Why would you be doing noinstr validation for lto builds? That doesn't > > > make sense. > > > > This is just to avoid a ton of noinstr warnings when we run objtool on > > vmlinux.o, but I'm also fine with skipping noinstr validation with LTO. > > Right, then we need to make --no-vmlinux work properly when > !DEBUG_ENTRY, which I think might be buggered due to us overriding the > argument when the objname ends with "vmlinux.o". Right. Can we just remove that and pass --vmlinux to objtool in link-vmlinux.sh, or is the override necessary somewhere else? > > > > +ifdef CONFIG_STACK_VALIDATION > > > > +ifneq ($(SKIP_STACK_VALIDATION),1) > > > > +cmd_ld_ko_o += \ > > > > + $(objtree)/tools/objtool/objtool \ > > > > + $(if $(CONFIG_UNWINDER_ORC),orc generate,check) \ > > > > + --module \ > > > > + $(if $(CONFIG_FRAME_POINTER),,--no-fp) \ > > > > + $(if $(CONFIG_GCOV_KERNEL),--no-unreachable,) \ > > > > + $(if $(CONFIG_RETPOLINE),--retpoline,) \ > > > > + $(if $(CONFIG_X86_SMAP),--uaccess,) \ > > > > + $(@:.ko=$(prelink-ext).o); > > > > + > > > > +endif # SKIP_STACK_VALIDATION > > > > +endif # CONFIG_STACK_VALIDATION > > > > > > What about the objtool invocation from link-vmlinux.sh ? > > > > What about it? The existing objtool_link invocation in link-vmlinux.sh > > works fine for our purposes as well. > > Well, I was wondering why you're adding yet another objtool invocation > while we already have one. Because we can't run objtool until we have compiled bitcode to native code, so for modules, we're need another invocation after everything has been compiled. Sami