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=-3.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 23A9FC433DF for ; Fri, 16 Oct 2020 12:43:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A9118207F7 for ; Fri, 16 Oct 2020 12:43:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Nm2Vvoo4" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2405407AbgJPMnF (ORCPT ); Fri, 16 Oct 2020 08:43:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37756 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2394970AbgJPMnF (ORCPT ); Fri, 16 Oct 2020 08:43:05 -0400 Received: from mail-io1-xd42.google.com (mail-io1-xd42.google.com [IPv6:2607:f8b0:4864:20::d42]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4F09AC061755 for ; Fri, 16 Oct 2020 05:43:05 -0700 (PDT) Received: by mail-io1-xd42.google.com with SMTP id r4so3616254ioh.0 for ; Fri, 16 Oct 2020 05:43:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:from:date:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=6hQgOzL6sOM6eLWh0nINz4OXRKDihiFpacrVqvj6Ks4=; b=Nm2Vvoo4AWTA69/l3zltGws3/Mza2vChrhkOniY8pO2FHFA7ridMw2ZIKKcAxDbQ2T 9/kPG9pB6n1Gjap21t+HD/2vaGlNl4WymcE+BwwCgU0qHmY/VdBXhDL7Ay/MNigXHClP WqFyttYMkFABeIeAOWOYt9wJLyodyN0TqN53U3lt0rc0Hk+XEcOpGQPX40+Ykd1yireD Vln0AIvphGZmE/PACGJNMSsIV9ssukyA8M1YfLV4VwopAiCHvNsRW/fvoul6zGzfo38H 48e5Qfif1dyZplAHCSbVLnYZPCIWA09nO9QSYEqOsw3TqttnfGlYF6bojnolK927XtW8 7jtw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:from:date:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to; bh=6hQgOzL6sOM6eLWh0nINz4OXRKDihiFpacrVqvj6Ks4=; b=S7z0jd3/mm5KmNC3WHUz8N6vjQvPsU5MLDyKYDYfpLgIXxNXSl5fqO9JoyJaoArfgM y1tQ89I6QXo1NJH5B63QgW4vJ7BJ7XMEEfN/czyTwIIJmrtnGB440l40l5BvzFavgI3s pBao2srpklB4Bv1ZCuoOlwi/Y9KJXLZzML7xnCRuwHCC7d7Bu2yGBdtz10HDEReGjipV RbYGydvrue3sBTfvNdWosDHfspLx9ivAyjLMmxtsLoB/7ZB8eGLz5hnUF9f4IhL4HPdl jM3ZObKkIOCH2TM8TGALeTsrPikdQx/68qlDVJXoh5vAS3+wSkR2JOJkb/tVhr2yLj8J VjuA== X-Gm-Message-State: AOAM5335V+BFCvAW8nIqAmxpsyfE1TnOlDS+9iF33EFd6GSdquIY7OKS PLasBoRYlVXcfXfMmrDKeOY= X-Google-Smtp-Source: ABdhPJz9UNIhUyTQwk4IvX62eGSUDwZ3pxeSB2tWiUIepRrm8qiHW5OgmLsMFbkxZEl985eyf/xn6A== X-Received: by 2002:a5d:96ce:: with SMTP id r14mr2180718iol.146.1602852184449; Fri, 16 Oct 2020 05:43:04 -0700 (PDT) Received: from rani.riverdale.lan ([2001:470:1f07:5f3::b55f]) by smtp.gmail.com with ESMTPSA id r4sm2289004ilc.32.2020.10.16.05.43.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 16 Oct 2020 05:43:03 -0700 (PDT) Sender: Arvind Sankar From: Arvind Sankar X-Google-Original-From: Arvind Sankar Date: Fri, 16 Oct 2020 08:43:01 -0400 To: Borislav Petkov Cc: Arvind Sankar , x86@kernel.org, Joerg Roedel , linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 5/5] x86/head/64: Disable stack protection for head$(BITS).o Message-ID: <20201016124301.GA1040839@rani.riverdale.lan> References: <20201008191623.2881677-1-nivedita@alum.mit.edu> <20201008191623.2881677-6-nivedita@alum.mit.edu> <20201016111703.GD8483@zn.tnic> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20201016111703.GD8483@zn.tnic> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Oct 16, 2020 at 01:17:03PM +0200, Borislav Petkov wrote: > On Thu, Oct 08, 2020 at 03:16:23PM -0400, Arvind Sankar wrote: > > On 64-bit, the startup_64_setup_env() function added in > > 866b556efa12 ("x86/head/64: Install startup GDT") > > has stack protection enabled because of set_bringup_idt_handler(). > > Where? I don't see it. > > I have > > CONFIG_STACKPROTECTOR=y > # CONFIG_STACKPROTECTOR_STRONG is not set You need STACKPROTECTOR_STRONG -- I was testing with defconfig and the option is enabled by default. You also need AMD_MEM_ENCRYPT enabled, which it looks like you do. > > and a __stack_chk_fail call is nowhere to be found in the resulting > head64.s file. > > startup_64_setup_env: > # arch/x86/kernel/head64.c:91: return ptr - (void *)_text + (void *)physaddr; > leaq startup_gdt(%rdi), %rax #, tmp99 > # arch/x86/kernel/head64.c:91: return ptr - (void *)_text + (void *)physaddr; > subq $_text, %rax #, tmp101 > movq %rax, startup_gdt_descr+2(%rip) # tmp101, startup_gdt_descr.address > # ./arch/x86/include/asm/desc.h:209: asm volatile("lgdt %0"::"m" (*dtr)); > #APP > # 209 "./arch/x86/include/asm/desc.h" 1 > lgdt startup_gdt_descr(%rip) # startup_gdt_descr > # 0 "" 2 > # arch/x86/kernel/head64.c:600: asm volatile("movl %%eax, %%ds\n" > #NO_APP > movl $24, %eax #, tmp102 > #APP > # 600 "arch/x86/kernel/head64.c" 1 > movl %eax, %ds > movl %eax, %ss > movl %eax, %es > > # 0 "" 2 > # arch/x86/kernel/head64.c:91: return ptr - (void *)_text + (void *)physaddr; > #NO_APP > leaq bringup_idt_table(%rdi), %r9 #, tmp105 > leaq bringup_idt_descr(%rdi), %r8 #, tmp103 > leaq vc_no_ghcb(%rdi), %rsi #, tmp107 > # arch/x86/kernel/head64.c:91: return ptr - (void *)_text + (void *)physaddr; > subq $_text, %r9 #, _11 > subq $_text, %r8 #, _8 > subq $_text, %rsi #, tmp109 > # arch/x86/kernel/head64.c:572: set_bringup_idt_handler(idt, X86_TRAP_VC, handler); > movq %r9, %rdi # _11, > call set_bringup_idt_handler.constprop.0 # > # arch/x86/kernel/head64.c:575: desc->address = (unsigned long)idt; > movq %r9, 2(%r8) # _11, MEM[(struct desc_ptr *)_8].address > # ./arch/x86/include/asm/desc.h:214: asm volatile("lidt %0"::"m" (*dtr)); > #APP > # 214 "./arch/x86/include/asm/desc.h" 1 > lidt (%r8) # MEM[(const struct desc_ptr *)_8] > # 0 "" 2 > # arch/x86/kernel/head64.c:605: } > #NO_APP > ret > > -- > Regards/Gruss, > Boris. > > https://people.kernel.org/tglx/notes-about-netiquette