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=-8.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 ACD50C43331 for ; Thu, 26 Mar 2020 20:11:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7E19E206E6 for ; Thu, 26 Mar 2020 20:11:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=alien8.de header.i=@alien8.de header.b="c0tBcOqS" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727984AbgCZULu (ORCPT ); Thu, 26 Mar 2020 16:11:50 -0400 Received: from mail.skyhub.de ([5.9.137.197]:57510 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726363AbgCZULu (ORCPT ); Thu, 26 Mar 2020 16:11:50 -0400 Received: from zn.tnic (p200300EC2F0A49004CB08B568021E004.dip0.t-ipconnect.de [IPv6:2003:ec:2f0a:4900:4cb0:8b56:8021:e004]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id 2DC961EC0626; Thu, 26 Mar 2020 21:11:48 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1585253508; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:in-reply-to:in-reply-to: references:references; bh=PrESSnpiQpeyEnZVO2sr/PNnhIexYw4+4+Gg/n72Er4=; b=c0tBcOqSU9e4nZEuADM41EdBHYNpKdFJnzwnJhbLoIplCRJmBnMhYr9zSIUj1feHQgB4Iq tmEJJKOozc+Ct9IpRyAyXm8C1Xpvm29alFj6PkbT8VSI5bzj97jwwYZTvxNnw9aDp4wz4Y IJ8curNYCqmhBe+EF5B1FQ7b+eVjpbw= Date: Thu, 26 Mar 2020 21:11:42 +0100 From: Borislav Petkov To: Kees Cook Cc: "H.J. Lu" , linux-kernel@vger.kernel.org, Andy Lutomirski , Thomas Gleixner , Thomas Lendacky , Sami Tolvanen , Heiko Carstens , Ingo Molnar , "H . Peter Anvin" , x86@kernel.org, Arnd Bergmann , linux-arch@vger.kernel.org, Yu-cheng Yu Subject: Re: [PATCH 1/2] Add RUNTIME_DISCARD_EXIT to generic DISCARDS Message-ID: <20200326201142.GJ11398@zn.tnic> References: <20200326193021.255002-1-hjl.tools@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20200326193021.255002-1-hjl.tools@gmail.com> 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 Thu, Mar 26, 2020 at 12:30:20PM -0700, H.J. Lu wrote: > In x86 kernel, .exit.text and .exit.data sections are discarded at > runtime, not by linker. Add RUNTIME_DISCARD_EXIT to generic DISCARDS > and define it in x86 kernel linker script to keep them. > > Signed-off-by: H.J. Lu > Reviewed-by: Kees Cook > --- > arch/x86/kernel/vmlinux.lds.S | 1 + > include/asm-generic/vmlinux.lds.h | 10 ++++++++-- > 2 files changed, 9 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S > index e3296aa028fe..7206e1ac23dd 100644 > --- a/arch/x86/kernel/vmlinux.lds.S > +++ b/arch/x86/kernel/vmlinux.lds.S > @@ -21,6 +21,7 @@ > #define LOAD_OFFSET __START_KERNEL_map > #endif > > +#define RUNTIME_DISCARD_EXIT > #define EMITS_PT_NOTE > #define RO_EXCEPTION_TABLE_ALIGN 16 > > diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h > index e00f41aa8ec4..6b943fb8c5fd 100644 > --- a/include/asm-generic/vmlinux.lds.h > +++ b/include/asm-generic/vmlinux.lds.h > @@ -894,10 +894,16 @@ > * section definitions so that such archs put those in earlier section > * definitions. > */ > +#ifdef RUNTIME_DISCARD_EXIT > +#define EXIT_DISCARDS > +#else > +#define EXIT_DISCARDS \ > + EXIT_TEXT \ > + EXIT_DATA > +#endif /me goes back and reads the old thread on this... Kees, do you expect other arches to actually need this RUNTIME_DISCARD_EXIT thing or was that a hypothetical thing? /me searches more... oh, there's a patchset from you https://lkml.kernel.org/r/20200228002244.15240-1-keescook@chromium.org which already contains this patch *and* an ARM64 patch which defines RUNTIME_DISCARD_EXIT so I'm guessing ARM64 wants to discard at runtime too. Which leaves the question why is H.J. sending that patch separate and you carry it in a patchset about orphan section warning? Seems like it wants to be in your patchset? Thx. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette