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=-2.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham 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 9F3F7C43381 for ; Fri, 1 Mar 2019 15:08:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6977120850 for ; Fri, 1 Mar 2019 15:08:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="dSniS5hX" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388559AbfCAPIA (ORCPT ); Fri, 1 Mar 2019 10:08:00 -0500 Received: from merlin.infradead.org ([205.233.59.134]:57248 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725966AbfCAPH7 (ORCPT ); Fri, 1 Mar 2019 10:07:59 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=In-Reply-To:Content-Transfer-Encoding: Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Sender:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help: List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=VFOTBGnenStc7irbPbVwOgwqyQ6Emq7ZDqgr09LaHTg=; b=dSniS5hX3773Ymspu80OJs/UPN xeLiuYh4AYqY+tcIe7FUq7vQCG9EegeCtAJXgQaOPUekxXVKDjW5MKYadBURV742u323LV1qG0J9v oimBJdTwSGXxgehqA3rPx0kDOW3bzQ5jvn90/ICCEN/PwYjgZba/n/k58YFo8yGz7P8wogGmEwHSO atZL2RSjaht68oBqK+CMIUSh14AqCH+P6QT/562pyApn5xxN6y2acn1PIvqZoFH283FjJQ0xA1FTa vcnsjH+3uIsxLE3MoUOdIU5zlZvrwP+0NwGlt4zsQ2A1Pfwrq/y/MQx8fIRqQ4j9OCeXpe2dGfz0o iyo4mxLA==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1gzjlI-0000Nl-0S; Fri, 01 Mar 2019 15:07:44 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id BDFC5239359C0; Fri, 1 Mar 2019 16:07:42 +0100 (CET) Date: Fri, 1 Mar 2019 16:07:42 +0100 From: Peter Zijlstra To: hpa@zytor.com Cc: Thomas Gleixner , Linus Torvalds , Julien Thierry , Will Deacon , Andy Lutomirski , Ingo Molnar , Linux List Kernel Mailing , "linux-alpha@vger.kernel.org" , Ingo Molnar , Catalin Marinas , James Morse , valentin.schneider@arm.com, Brian Gerst , Josh Poimboeuf , Andrew Lutomirski , Borislav Petkov , Denys Vlasenko Subject: Re: [RFC][PATCH] objtool: STAC/CLAC validation Message-ID: <20190301150742.GU32534@hirez.programming.kicks-ass.net> References: <20190222222635.GK14054@worktop.programming.kicks-ass.net> <20190223083942.GF32477@hirez.programming.kicks-ass.net> <15DE0017-9AE5-4E7A-96CD-E5E9F5B72516@zytor.com> <20190225132103.GD32494@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20190225132103.GD32494@hirez.programming.kicks-ass.net> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Feb 25, 2019 at 02:21:03PM +0100, Peter Zijlstra wrote: > On Mon, Feb 25, 2019 at 12:47:00AM -0800, hpa@zytor.com wrote: > > It doesn't have to understand the contents of the memop, but it seems > > that the presence of a modrm with mode ≠ 3 should be plenty. It needs > > to know that much in order to know the length of instructions anyway. > > For extra credit, ignore LEA or hinting instructions. > > A little something like so then? $ ./objtool check --no-fp --backtrace ../../defconfig-build/arch/x86/lib/usercopy_64.o ../../defconfig-build/arch/x86/lib/usercopy_64.o: warning: objtool: .altinstr_replacement+0x3: UACCESS disable without MEMOPs: __clear_user() ../../defconfig-build/arch/x86/lib/usercopy_64.o: warning: objtool: __clear_user()+0x3a: (alt) ../../defconfig-build/arch/x86/lib/usercopy_64.o: warning: objtool: __clear_user()+0x2e: (branch) ../../defconfig-build/arch/x86/lib/usercopy_64.o: warning: objtool: __clear_user()+0x18: (branch) ../../defconfig-build/arch/x86/lib/usercopy_64.o: warning: objtool: .altinstr_replacement+0xffffffffffffffff: (branch) ../../defconfig-build/arch/x86/lib/usercopy_64.o: warning: objtool: __clear_user()+0x5: (alt) ../../defconfig-build/arch/x86/lib/usercopy_64.o: warning: objtool: __clear_user()+0x0: <=== (func) 0000000000000000 <__clear_user>: 0: e8 00 00 00 00 callq 5 <__clear_user+0x5> 1: R_X86_64_PLT32 __fentry__-0x4 5: 90 nop 6: 90 nop 7: 90 nop 8: 48 89 f0 mov %rsi,%rax b: 48 c1 ee 03 shr $0x3,%rsi f: 83 e0 07 and $0x7,%eax 12: 48 89 f1 mov %rsi,%rcx 15: 48 85 c9 test %rcx,%rcx 18: 74 0f je 29 <__clear_user+0x29> 1a: 48 c7 07 00 00 00 00 movq $0x0,(%rdi) 21: 48 83 c7 08 add $0x8,%rdi 25: ff c9 dec %ecx 27: 75 f1 jne 1a <__clear_user+0x1a> 29: 48 89 c1 mov %rax,%rcx 2c: 85 c9 test %ecx,%ecx 2e: 74 0a je 3a <__clear_user+0x3a> 30: c6 07 00 movb $0x0,(%rdi) 33: 48 ff c7 inc %rdi 36: ff c9 dec %ecx 38: 75 f6 jne 30 <__clear_user+0x30> 3a: 90 nop 3b: 90 nop 3c: 90 nop 3d: 48 89 c8 mov %rcx,%rax 40: c3 retq Seems correct. Not sure you want to go fix that though. Let me know if you want more output. 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=-2.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham 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 B37A7C43381 for ; Fri, 1 Mar 2019 15:07:55 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 7A07A20850 for ; Fri, 1 Mar 2019 15:07:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="kNrpyQ3w"; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="ItCmRukD" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7A07A20850 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=9hGi4PsBRWUl/AeHyFop69OSzqhBYUM5E5ffZuikieg=; b=kNrpyQ3wHSR3aJ a9eG9NPwpeyd81li+lOkWxzhdxhzMCgWsHt4ZzEvCQ6Eh70ugA38uTRGVaBYighz6siOV4mIgJxui DWCLv/DF9cz0uurrsJ4jxQekd1F3e4uZZzLekKDEcVLraqR/MjWQgn85VwfnzDmKeKwSEtjmygbIa dyiuYV3IQW10Y0yHooUfBLT66SO3QaeuO4Nz96EMF9M625gV2ueIwU5GuIOrmiLKUcvQRb85AwfKF g/OOyQ6nhHQirmV61by5C5+vASSt/4wqwnVWFPs53ZyhSrQdMuPV2SgnuA6W0hBA+tuQHCAGValmX qVhcPj5w02DUCyvwdsaQ==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gzjlP-0003TL-9Z; Fri, 01 Mar 2019 15:07:51 +0000 Received: from merlin.infradead.org ([2001:8b0:10b:1231::1]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1gzjlN-0003Le-Ej for linux-arm-kernel@bombadil.infradead.org; Fri, 01 Mar 2019 15:07:49 +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-Transfer-Encoding: Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Sender:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help: List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=Ats9Q6+82Vuy51pqczDbsKBHGSVK8EqUeoZD04JaVj4=; b=ItCmRukDGWN0Iv29lkjPp9T79V R2uvYuVtAnaVb2KRRY0gC+IkeXhKf+hPMR4P/WeMNWOJiObeyhDzj3lZ7k90+Kk0wFq+zImz3bpuP tEjXIhiP3H4G6MGrh/CMo7uJno+Go9rL/4eezviVD/ZV2HkbGhFZaSt9dhFfvoWSeK0IHfU/U9BXL shJokBQzv8NRTmFXdkjqL9ngIXOynh0zpFVUnpqK/cM/LmFm7lq9psidBakAfOafaWQOg9V6yfzgj ujVIDJ4gWeh7AvBKoY7hGYxfAcEFUHxYSDurTXdv1TbHJhRgTUYyeduJugTgV6GOFWTVvUfTPB79h 1YLmTkKw==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1gzjlI-0000Nl-0S; Fri, 01 Mar 2019 15:07:44 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id BDFC5239359C0; Fri, 1 Mar 2019 16:07:42 +0100 (CET) Date: Fri, 1 Mar 2019 16:07:42 +0100 From: Peter Zijlstra To: hpa@zytor.com Subject: Re: [RFC][PATCH] objtool: STAC/CLAC validation Message-ID: <20190301150742.GU32534@hirez.programming.kicks-ass.net> References: <20190222222635.GK14054@worktop.programming.kicks-ass.net> <20190223083942.GF32477@hirez.programming.kicks-ass.net> <15DE0017-9AE5-4E7A-96CD-E5E9F5B72516@zytor.com> <20190225132103.GD32494@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20190225132103.GD32494@hirez.programming.kicks-ass.net> User-Agent: Mutt/1.10.1 (2018-07-13) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Denys Vlasenko , Josh Poimboeuf , Julien Thierry , Catalin Marinas , valentin.schneider@arm.com, Will Deacon , Linux List Kernel Mailing , Andy Lutomirski , Ingo Molnar , James Morse , Andrew Lutomirski , Brian Gerst , Borislav Petkov , Thomas Gleixner , Linus Torvalds , Ingo Molnar , "linux-alpha@vger.kernel.org" Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org T24gTW9uLCBGZWIgMjUsIDIwMTkgYXQgMDI6MjE6MDNQTSArMDEwMCwgUGV0ZXIgWmlqbHN0cmEg d3JvdGU6Cj4gT24gTW9uLCBGZWIgMjUsIDIwMTkgYXQgMTI6NDc6MDBBTSAtMDgwMCwgaHBhQHp5 dG9yLmNvbSB3cm90ZToKPiA+IEl0IGRvZXNuJ3QgaGF2ZSB0byB1bmRlcnN0YW5kIHRoZSBjb250 ZW50cyBvZiB0aGUgbWVtb3AsIGJ1dCBpdCBzZWVtcwo+ID4gdGhhdCB0aGUgcHJlc2VuY2Ugb2Yg YSBtb2RybSB3aXRoIG1vZGUg4omgIDMgc2hvdWxkIGJlIHBsZW50eS4gSXQgbmVlZHMKPiA+IHRv IGtub3cgdGhhdCBtdWNoIGluIG9yZGVyIHRvIGtub3cgdGhlIGxlbmd0aCBvZiBpbnN0cnVjdGlv bnMgYW55d2F5Lgo+ID4gRm9yIGV4dHJhIGNyZWRpdCwgaWdub3JlIExFQSBvciBoaW50aW5nIGlu c3RydWN0aW9ucy4KPiAKPiBBIGxpdHRsZSBzb21ldGhpbmcgbGlrZSBzbyB0aGVuPwoKCiQgLi9v Ymp0b29sIGNoZWNrIC0tbm8tZnAgLS1iYWNrdHJhY2UgLi4vLi4vZGVmY29uZmlnLWJ1aWxkL2Fy Y2gveDg2L2xpYi91c2VyY29weV82NC5vCi4uLy4uL2RlZmNvbmZpZy1idWlsZC9hcmNoL3g4Ni9s aWIvdXNlcmNvcHlfNjQubzogd2FybmluZzogb2JqdG9vbDogLmFsdGluc3RyX3JlcGxhY2VtZW50 KzB4MzogVUFDQ0VTUyBkaXNhYmxlIHdpdGhvdXQgTUVNT1BzOiBfX2NsZWFyX3VzZXIoKQouLi8u Li9kZWZjb25maWctYnVpbGQvYXJjaC94ODYvbGliL3VzZXJjb3B5XzY0Lm86IHdhcm5pbmc6IG9i anRvb2w6IF9fY2xlYXJfdXNlcigpKzB4M2E6IChhbHQpCi4uLy4uL2RlZmNvbmZpZy1idWlsZC9h cmNoL3g4Ni9saWIvdXNlcmNvcHlfNjQubzogd2FybmluZzogb2JqdG9vbDogX19jbGVhcl91c2Vy KCkrMHgyZTogKGJyYW5jaCkKLi4vLi4vZGVmY29uZmlnLWJ1aWxkL2FyY2gveDg2L2xpYi91c2Vy Y29weV82NC5vOiB3YXJuaW5nOiBvYmp0b29sOiBfX2NsZWFyX3VzZXIoKSsweDE4OiAoYnJhbmNo KQouLi8uLi9kZWZjb25maWctYnVpbGQvYXJjaC94ODYvbGliL3VzZXJjb3B5XzY0Lm86IHdhcm5p bmc6IG9ianRvb2w6IC5hbHRpbnN0cl9yZXBsYWNlbWVudCsweGZmZmZmZmZmZmZmZmZmZmY6IChi cmFuY2gpCi4uLy4uL2RlZmNvbmZpZy1idWlsZC9hcmNoL3g4Ni9saWIvdXNlcmNvcHlfNjQubzog d2FybmluZzogb2JqdG9vbDogX19jbGVhcl91c2VyKCkrMHg1OiAoYWx0KQouLi8uLi9kZWZjb25m aWctYnVpbGQvYXJjaC94ODYvbGliL3VzZXJjb3B5XzY0Lm86IHdhcm5pbmc6IG9ianRvb2w6IF9f Y2xlYXJfdXNlcigpKzB4MDogPD09PSAoZnVuYykKCgowMDAwMDAwMDAwMDAwMDAwIDxfX2NsZWFy X3VzZXI+OgogICAwOiAgIGU4IDAwIDAwIDAwIDAwICAgICAgICAgIGNhbGxxICA1IDxfX2NsZWFy X3VzZXIrMHg1PgogICAxOiBSX1g4Nl82NF9QTFQzMiAgICAgICBfX2ZlbnRyeV9fLTB4NAogICA1 OiAgIDkwICAgICAgICAgICAgICAgICAgICAgIG5vcAogICA2OiAgIDkwICAgICAgICAgICAgICAg ICAgICAgIG5vcAogICA3OiAgIDkwICAgICAgICAgICAgICAgICAgICAgIG5vcAogICA4OiAgIDQ4 IDg5IGYwICAgICAgICAgICAgICAgIG1vdiAgICAlcnNpLCVyYXgKICAgYjogICA0OCBjMSBlZSAw MyAgICAgICAgICAgICBzaHIgICAgJDB4MywlcnNpCiAgIGY6ICAgODMgZTAgMDcgICAgICAgICAg ICAgICAgYW5kICAgICQweDcsJWVheAogIDEyOiAgIDQ4IDg5IGYxICAgICAgICAgICAgICAgIG1v diAgICAlcnNpLCVyY3gKICAxNTogICA0OCA4NSBjOSAgICAgICAgICAgICAgICB0ZXN0ICAgJXJj eCwlcmN4CiAgMTg6ICAgNzQgMGYgICAgICAgICAgICAgICAgICAgamUgICAgIDI5IDxfX2NsZWFy X3VzZXIrMHgyOT4KICAxYTogICA0OCBjNyAwNyAwMCAwMCAwMCAwMCAgICBtb3ZxICAgJDB4MCwo JXJkaSkKICAyMTogICA0OCA4MyBjNyAwOCAgICAgICAgICAgICBhZGQgICAgJDB4OCwlcmRpCiAg MjU6ICAgZmYgYzkgICAgICAgICAgICAgICAgICAgZGVjICAgICVlY3gKICAyNzogICA3NSBmMSAg ICAgICAgICAgICAgICAgICBqbmUgICAgMWEgPF9fY2xlYXJfdXNlcisweDFhPgogIDI5OiAgIDQ4 IDg5IGMxICAgICAgICAgICAgICAgIG1vdiAgICAlcmF4LCVyY3gKICAyYzogICA4NSBjOSAgICAg ICAgICAgICAgICAgICB0ZXN0ICAgJWVjeCwlZWN4CiAgMmU6ICAgNzQgMGEgICAgICAgICAgICAg ICAgICAgamUgICAgIDNhIDxfX2NsZWFyX3VzZXIrMHgzYT4KICAzMDogICBjNiAwNyAwMCAgICAg ICAgICAgICAgICBtb3ZiICAgJDB4MCwoJXJkaSkKICAzMzogICA0OCBmZiBjNyAgICAgICAgICAg ICAgICBpbmMgICAgJXJkaQogIDM2OiAgIGZmIGM5ICAgICAgICAgICAgICAgICAgIGRlYyAgICAl ZWN4CiAgMzg6ICAgNzUgZjYgICAgICAgICAgICAgICAgICAgam5lICAgIDMwIDxfX2NsZWFyX3Vz ZXIrMHgzMD4KICAzYTogICA5MCAgICAgICAgICAgICAgICAgICAgICBub3AKICAzYjogICA5MCAg ICAgICAgICAgICAgICAgICAgICBub3AKICAzYzogICA5MCAgICAgICAgICAgICAgICAgICAgICBu b3AKICAzZDogICA0OCA4OSBjOCAgICAgICAgICAgICAgICBtb3YgICAgJXJjeCwlcmF4CiAgNDA6 ICAgYzMgICAgICAgICAgICAgICAgICAgICAgcmV0cQoKClNlZW1zIGNvcnJlY3QuIE5vdCBzdXJl IHlvdSB3YW50IHRvIGdvIGZpeCB0aGF0IHRob3VnaC4gTGV0IG1lIGtub3cgaWYKeW91IHdhbnQg bW9yZSBvdXRwdXQuCgpfX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19f X19fXwpsaW51eC1hcm0ta2VybmVsIG1haWxpbmcgbGlzdApsaW51eC1hcm0ta2VybmVsQGxpc3Rz LmluZnJhZGVhZC5vcmcKaHR0cDovL2xpc3RzLmluZnJhZGVhZC5vcmcvbWFpbG1hbi9saXN0aW5m by9saW51eC1hcm0ta2VybmVsCg==