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=-4.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 A5C07C433DF for ; Thu, 25 Jun 2020 07:47:46 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id 0615120789 for ; Thu, 25 Jun 2020 07:47:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="UIuIqigV" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0615120789 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kernel-hardening-return-19160-kernel-hardening=archiver.kernel.org@lists.openwall.com Received: (qmail 32062 invoked by uid 550); 25 Jun 2020 07:47:37 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Received: (qmail 32030 invoked from network); 25 Jun 2020 07:47:37 -0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=jlp9yRmob93dOT2KqKFc9+KfQV0pPJXXFdCgHBP2kM0=; b=UIuIqigVl3WX7R1skgg/Iif4x9 hy/pTl2n1RYBArKVSpmY8DjS2unkPxAVMZxi3vZw7HkiMQ+Q+KOu3kiQG6sz78NeMA4DjcPNCGbbC ieWTzZr/0PFbRVojQSNhSqU5Ygr0XL2gN/oeuqxuiR3yrMqgmnRta6jruo86RnRYVv3F8szsLT28j IJP5z91KUq5xvrgosAkmgdhmv1RD+jV8oL87ketaFGyEAK09VPwLfB5LapFSpaYn4XQkDKv3Z97sc mhFdebUs1E6/vlLnkbP5Ta5PkZAqSKNE5SxdS4jK+SauMNXF8v8mFghUbAWe7Ae9OCr1g2cf+23N+ DBACpvNw==; Date: Thu, 25 Jun 2020 09:47:16 +0200 From: Peter Zijlstra To: Sami Tolvanen 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: <20200625074716.GX4817@hirez.programming.kicks-ass.net> References: <20200624203200.78870-1-samitolvanen@google.com> <20200624203200.78870-6-samitolvanen@google.com> <20200624211908.GT4817@hirez.programming.kicks-ass.net> <20200624214925.GB120457@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200624214925.GB120457@google.com> 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". > > > +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.