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=-14.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_IN_DEF_DKIM_WL autolearn=unavailable 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 62131CA9EA9 for ; Fri, 18 Oct 2019 17:32:51 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id AC4E4222C3 for ; Fri, 18 Oct 2019 17:32:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="Q2GrSm+O" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AC4E4222C3 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kernel-hardening-return-17045-kernel-hardening=archiver.kernel.org@lists.openwall.com Received: (qmail 32305 invoked by uid 550); 18 Oct 2019 17:32:45 -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 32284 invoked from network); 18 Oct 2019 17:32:44 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=LUCkDiO1QUpPk5cl+dZgUeLa1d4lsLLAG2MEy31ElWU=; b=Q2GrSm+Odfy9jVEDqMmfnpv1JF6tDvJ9iXYBvf5rjH3en0ATo4AgQjw2pQDojlKoaS 9fBS4aMFJ5dZwD9OigzTjU849InPSdBgGRC+uZEt3xD+a4RKHVALWELFRgwg2SA4Hrzq zb2RgQ0REmeyvR9a4FeSiZ73kVsr69wvb6c31MRdP3Bvd2XsEJze6gbRaEFiobpWXpeP Jy5YplzkCXmKDyVKqgUBpRu2Xoxis9XWxkxStyjOq8Q2jrPByqwE/lIB22HRWbIoxhAw w2b9PGOjxqmyIOBybNGNqSsdSOP6Tyg2PirfWZOi7lJ8gecCO3g1JCJKWpU8SIivdJr/ RIuA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=LUCkDiO1QUpPk5cl+dZgUeLa1d4lsLLAG2MEy31ElWU=; b=PUOMSlK6FMHz4c+/tH+YJH5uSzcDaO1jaDxLTciufSqgGT0P5nMU1rnb1+QhvtTk2y pEN1nXHHAGU5yU+y4uDAb2FJ/hLPVEea0SocTzMniTZBqGOjNXK4eCfU4wKRx4pFCaYN ANDpyd1wSfxEmXmASV961eTmMCPiqRbEM+tQoLMBKibGYg4wef4RxutsQ1vTEoNC/0go GADISy9tB+Q1QuoBzdrb5CwJ3BIzzpxS1GRgA4N+/0e0sP4Bh2SDZ3imdJzj/ECRMhno IAtqm/nrRZTiRXXH+K91/rKGP8+91mrBNrBwUf3iKAklhwHTkzG+ZrwF3VxVR+g0NoLr FHAw== X-Gm-Message-State: APjAAAV/NIIEbT+EPgP5TGTun1TufXFIaO0QalJCV+MopHH3R67090ZH 5XSqKtFS0i4ZQPgl/TLb6LKOKmJD4UzUlFAXoWX4WA== X-Google-Smtp-Source: APXvYqyiP1Zzh4FMjPyyDPFh7Wpil1drk2/6fs3Sl6Id4xkJb/P7azXpHLFJ3B/tWIF35J82NWyTkkF5okrslIJan50= X-Received: by 2002:a63:5448:: with SMTP id e8mr11186188pgm.10.1571419951879; Fri, 18 Oct 2019 10:32:31 -0700 (PDT) MIME-Version: 1.0 References: <20191018161033.261971-1-samitolvanen@google.com> <20191018161033.261971-6-samitolvanen@google.com> In-Reply-To: <20191018161033.261971-6-samitolvanen@google.com> From: Nick Desaulniers Date: Fri, 18 Oct 2019 10:32:20 -0700 Message-ID: Subject: Re: [PATCH 05/18] arm64: kbuild: reserve reg x18 from general allocation by the compiler To: Sami Tolvanen Cc: Will Deacon , Catalin Marinas , Steven Rostedt , Ard Biesheuvel , Dave Martin , Kees Cook , Laura Abbott , Mark Rutland , clang-built-linux , kernel-hardening@lists.openwall.com, Linux ARM , LKML Content-Type: text/plain; charset="UTF-8" On Fri, Oct 18, 2019 at 9:11 AM Sami Tolvanen wrote: > > From: Ard Biesheuvel > > Before we can start using register x18 for a special purpose (as permitted > by the AAPCS64 ABI), we need to tell the compiler that it is off limits > for general allocation. So tag it as 'fixed', yep, but... > and remove the mention from > the LL/SC compiler flag override. was that cut/dropped from this patch? > > Link: https://patchwork.kernel.org/patch/9836881/ ^ Looks like it. Maybe it doesn't matter, but if sending a V2, maybe the commit message to be updated? > Signed-off-by: Ard Biesheuvel > Signed-off-by: Sami Tolvanen If sending a V2 with the above cleaned up, you may also include: Reviewed-by: Nick Desaulniers I like how this does not conditionally reserve it based on the CONFIG for SCS. Hopefully later patches don't wrap it, but I haven't looked through all of them yet. > --- > arch/arm64/Makefile | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile > index 2c0238ce0551..1c7b276bc7c5 100644 > --- a/arch/arm64/Makefile > +++ b/arch/arm64/Makefile > @@ -55,7 +55,7 @@ endif > > KBUILD_CFLAGS += -mgeneral-regs-only $(lseinstr) $(brokengasinst) \ > $(compat_vdso) $(cc_has_k_constraint) > -KBUILD_CFLAGS += -fno-asynchronous-unwind-tables > +KBUILD_CFLAGS += -fno-asynchronous-unwind-tables -ffixed-x18 > KBUILD_CFLAGS += $(call cc-disable-warning, psabi) > KBUILD_AFLAGS += $(lseinstr) $(brokengasinst) $(compat_vdso) > > -- > 2.23.0.866.gb869b98d4c-goog > -- Thanks, ~Nick Desaulniers