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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 218D2C10F11 for ; Wed, 10 Apr 2019 06:06:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id ECB6B2070D for ; Wed, 10 Apr 2019 06:06:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727382AbfDJGGz (ORCPT ); Wed, 10 Apr 2019 02:06:55 -0400 Received: from ozlabs.org ([203.11.71.1]:34679 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726693AbfDJGGz (ORCPT ); Wed, 10 Apr 2019 02:06:55 -0400 Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mail.ozlabs.org (Postfix) with ESMTPSA id 44fDFQ5M3vz9s7T; Wed, 10 Apr 2019 16:06:50 +1000 (AEST) From: Michael Ellerman To: Josh Poimboeuf , linux-kernel@vger.kernel.org Cc: x86@kernel.org, Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H . Peter Anvin" , Andy Lutomirski , Peter Zijlstra , Jiri Kosina , Waiman Long , Andrea Arcangeli , Jon Masters , Benjamin Herrenschmidt , Paul Mackerras , linuxppc-dev@lists.ozlabs.org, Martin Schwidefsky , Heiko Carstens , linux-s390@vger.kernel.org, Catalin Marinas , Will Deacon , linux-arm-kernel@lists.infradead.org, linux-arch@vger.kernel.org, Greg Kroah-Hartman , Tyler Hicks , Linus Torvalds Subject: Re: [PATCH RFC 3/5] powerpc/speculation: Add support for 'cpu_spec_mitigations=' cmdline options In-Reply-To: <91b92d8182d2f114d92c95689fcd4bb1a8dda1b0.1554396090.git.jpoimboe@redhat.com> References: <91b92d8182d2f114d92c95689fcd4bb1a8dda1b0.1554396090.git.jpoimboe@redhat.com> Date: Wed, 10 Apr 2019 16:06:50 +1000 Message-ID: <87pnpuwg05.fsf@concordia.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Josh Poimboeuf writes: > Configure powerpc CPU runtime speculation bug mitigations in accordance > with the 'cpu_spec_mitigations=' cmdline options. This affects > Meltdown, Spectre v1, Spectre v2, and Speculative Store Bypass. > > The default behavior is unchanged. > > Signed-off-by: Josh Poimboeuf > --- > Documentation/admin-guide/kernel-parameters.txt | 9 +++++---- > arch/powerpc/kernel/security.c | 6 +++--- > arch/powerpc/kernel/setup_64.c | 2 +- > 3 files changed, 9 insertions(+), 8 deletions(-) > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > index 29dc03971630..0e8eae1e8a25 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -2552,10 +2552,11 @@ > > off > Disable all speculative CPU mitigations. > - Equivalent to: nopti [x86] > + Equivalent to: nopti [x86, powerpc] > + nospectre_v1 [powerpc] > nospectre_v2 [x86] Not sure if you meant to omit powerpc from nospectre_v2? You have patched it in the code below. > spectre_v2_user=off [x86] > - spec_store_bypass_disable=off [x86] > + spec_store_bypass_disable=off [x86, powerpc] > l1tf=off [x86] > > auto (default) > @@ -2568,7 +2569,7 @@ > Equivalent to: pti=auto [x86] > spectre_v2=auto [x86] > spectre_v2_user=auto [x86] > - spec_store_bypass_disable=auto [x86] > + spec_store_bypass_disable=auto [x86, powerpc] > l1tf=flush [x86] > > auto,nosmt > @@ -2579,7 +2580,7 @@ > Equivalent to: pti=auto [x86] > spectre_v2=auto [x86] > spectre_v2_user=auto [x86] > - spec_store_bypass_disable=auto [x86] > + spec_store_bypass_disable=auto [x86, powerpc] > l1tf=flush,nosmt [x86] > > mminit_loglevel= > diff --git a/arch/powerpc/kernel/security.c b/arch/powerpc/kernel/security.c > index b33bafb8fcea..5aed4ad729ba 100644 > --- a/arch/powerpc/kernel/security.c > +++ b/arch/powerpc/kernel/security.c > @@ -57,7 +57,7 @@ void setup_barrier_nospec(void) > enable = security_ftr_enabled(SEC_FTR_FAVOUR_SECURITY) && > security_ftr_enabled(SEC_FTR_BNDS_CHK_SPEC_BAR); > > - if (!no_nospec) > + if (!no_nospec && cpu_spec_mitigations != CPU_SPEC_MITIGATIONS_OFF) > enable_barrier_nospec(enable); Adding a wrapper func that checks for CPU_SPEC_MITIGATIONS_OFF would make these a little less verbose, eg: if (!no_nospec && !cpu_spec_mitigations_off()) enable_barrier_nospec(enable); But that's a nitpick. > @@ -116,7 +116,7 @@ static int __init handle_nospectre_v2(char *p) > early_param("nospectre_v2", handle_nospectre_v2); > void setup_spectre_v2(void) > { > - if (no_spectrev2) > + if (no_spectrev2 || cpu_spec_mitigations == CPU_SPEC_MITIGATIONS_OFF) > do_btb_flush_fixups(); > else > btb_flush_enabled = true; > @@ -300,7 +300,7 @@ void setup_stf_barrier(void) > > stf_enabled_flush_types = type; > > - if (!no_stf_barrier) > + if (!no_stf_barrier && cpu_spec_mitigations != CPU_SPEC_MITIGATIONS_OFF) > stf_barrier_enable(enable); > } > > diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c > index ba404dd9ce1d..d9d796a66a79 100644 > --- a/arch/powerpc/kernel/setup_64.c > +++ b/arch/powerpc/kernel/setup_64.c > @@ -932,7 +932,7 @@ void setup_rfi_flush(enum l1d_flush_type types, bool enable) > > enabled_flush_types = types; > > - if (!no_rfi_flush) > + if (!no_rfi_flush || cpu_spec_mitigations != CPU_SPEC_MITIGATIONS_OFF) > rfi_flush_enable(enable); > } LGTM. Acked-by: Michael Ellerman (powerpc) cheers