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=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,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 72D3FC33CA1 for ; Wed, 8 Jan 2020 14:22:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 52B1820720 for ; Wed, 8 Jan 2020 14:22:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728929AbgAHOWy (ORCPT ); Wed, 8 Jan 2020 09:22:54 -0500 Received: from mout.kundenserver.de ([212.227.17.13]:37923 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727648AbgAHOWx (ORCPT ); Wed, 8 Jan 2020 09:22:53 -0500 Received: from mail-qk1-f170.google.com ([209.85.222.170]) by mrelayeu.kundenserver.de (mreue107 [212.227.15.145]) with ESMTPSA (Nemesis) id 1MCayD-1iyEm02WJP-009g9A for ; Wed, 08 Jan 2020 15:22:51 +0100 Received: by mail-qk1-f170.google.com with SMTP id z76so2773937qka.2 for ; Wed, 08 Jan 2020 06:22:51 -0800 (PST) X-Gm-Message-State: APjAAAV8q+zDK93TxOaNQU/1L4TYoN3Mq1eJxTvd4cjyqqkMcPOKTcGG n1yYyvwSgP3JNuxe+9le+Oz6ArqZQQHqwi0SzBg= X-Google-Smtp-Source: APXvYqyfqgQD2H5+TORrgk7UjrEH2d32T6FSbyTEIj1G/XZzi/vedpcHrmeg7cndEJWWjXDeHezpKOfItgKTCtvZnNc= X-Received: by 2002:a37:2f02:: with SMTP id v2mr4384139qkh.3.1578493370496; Wed, 08 Jan 2020 06:22:50 -0800 (PST) MIME-Version: 1.0 References: <20191111131252.921588318@infradead.org> <20191111132458.220458362@infradead.org> <20191111164703.GA11521@willie-the-truck> <20191111171955.GO4114@hirez.programming.kicks-ass.net> <20191111172541.GT5671@hirez.programming.kicks-ass.net> <20191112112950.GB17835@willie-the-truck> <20191113092636.GG4131@hirez.programming.kicks-ass.net> <20200108091628.7e548401@gandalf.local.home> In-Reply-To: <20200108091628.7e548401@gandalf.local.home> From: Arnd Bergmann Date: Wed, 8 Jan 2020 15:22:33 +0100 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH -v5mkII 13/17] arm/ftrace: Use __patch_text() To: Steven Rostedt Cc: Peter Zijlstra , Will Deacon , "the arch/x86 maintainers" , "linux-kernel@vger.kernel.org" , Masami Hiramatsu , bristot@redhat.com, Jason Baron , Linus Torvalds , Thomas Gleixner , Ingo Molnar , namit@vmware.com, "H. Peter Anvin" , Andy Lutomirski , Ard Biesheuvel , Josh Poimboeuf , Jessica Yu , Alexei Starovoitov , Mark Rutland , James Morse , Russell King , Rabin Vincent , Nicolas Pitre Content-Type: text/plain; charset="UTF-8" X-Provags-ID: V03:K1:biUHxl8UTZgOhX3GvGWcEFqJUAGaWoL4SLHx+vh+W2p7oNoE8/G DRBhhBRTZmKE/4dto4Z9z4Rq8Sdx8ph7rcS1uDMxHvcWunErXdw8tUVGPLSGzcvy5h4UXgu ZOi8TyDrjWd0NZTcnluaEBIhB5vxGb4VW6LbHpOcj/X6dRmo8fioovxMYQPDGd770P1EQmV jb1aDj7/ux57dRLLDs3Sw== X-UI-Out-Filterresults: notjunk:1;V03:K0:c8kA/IJVZHU=:nmtrTJ/8FJa2Z1/RTYZvEd V84dU2txZ82FDTtoWj+MGR/XhATia3/uvWClAaIctEnb4vpKvvgvbvEIfD0xtxMYYV6xR/u4T qh/q705lCv5rk6RbnTVfQIIH0YAVcbmbQjJZMnmL6enH4fjVxSz6K2eFn3EpCpLOj1HEBDj6e 1vFiJe0uAoMECGYH+MOXE2w/FBJ2KIyTqqX0ZY76Tjx8vyComS/O3UilqJ6a9Woax7CFhmjal TSC0HKmgMaeelsfh+52f9uB1HafNnsS/NUL0VLRmy+xH1SNdnc6IrHQnOe8WkMaP4n4t1mv9M zDh07IXXgFIsSEHA3NayPnuSW/P2k8jrJByno1Jm3t8uTWrhIXuCPHee37IatGvcqk3Mqh8il fuZoMq8lNBHTpewSuC0+JcKQjeeUJkP2kSJ0Xl1A124/uQ+bsLc6rogk8/dsGQ4vRHdVLvjX/ o49U1rPh7N1Hcw1HdxOaUwn8Q+Eyni8gNEYxmruEP0LzVob6X1z85Mi8fOrzEPJn1sVVIA7uN /ZFYe1PvaNvFtH2wNovvJ/eSXfvWJybDUn9kd3OGGJBw0mCsG1u/bm7clLbW5+46hGscUuXLZ caBlMQcBywnR1JMK0aXWhWQ9NaEni02rXb09BWlZumkAh1jIxjEPxL7K4urx++or9HKg6X2Be bq9V3ASbjunmHj+sfJBp3SdYZkhUWR6UBQRX7vje94PPQJCu3MrPDgCB9mC91vJVGAOlpCdpT 16PLTfFaw36WWd5B/IbtVCCbw+jWCzQxKBKflxEuXmiUwYFWjq3Nm4T4beCGArPtHF0CAn/ww D70+qkzBBG7ayWWODItI4CsEl0popjurMt1/uVOeNwghHHzo8mgb8C9tyj2oZnRq2ZeU4wV8s J9OL6ekrsewjDc9AOj+g== Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 8, 2020 at 3:16 PM Steven Rostedt wrote: > > On Wed, 8 Jan 2020 13:22:52 +0100 > Arnd Bergmann wrote: > > > The problem is that we don't have a BE32 definition of > > __opcode_to_mem_thumb32, mostly because no hardware > > supports that. > > > > One possible workaround is a big ugly: > > > > diff --git a/arch/arm/kernel/patch.c b/arch/arm/kernel/patch.c > > index d0a05a3bdb96..1067fd122897 100644 > > --- a/arch/arm/kernel/patch.c > > +++ b/arch/arm/kernel/patch.c > > @@ -90,9 +90,11 @@ void __kprobes __patch_text_real(void *addr, > > unsigned int insn, bool remap) > > > > size = sizeof(u32); > > } else { > > +#ifdef CONFIG_THUMB2_KERNEL > > if (thumb2) > > If we change the above to: > > if (IS_ENABLED(CONFIG_THUMB2_KERNEL) && thumb2) > > Would the compiler optmize out __opcode_to_mem_thumb32(). We would need > to add a declaration for it, but wont need to define it. At least we > wont have nasty #ifdef logic in the code. If we add a declaration for it, I think no change to patch.c is needed, as 'thumb2' already has compile-time constant value equal to IS_ENABLED(CONFIG_THUMB2_KERNEL). I'll try it out. Arnd