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Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:39344) by pandora.armlinux.org.uk with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1jvHdD-0004xm-TI; Tue, 14 Jul 2020 10:53:47 +0100 Received: from linux by shell.armlinux.org.uk with local (Exim 4.92) (envelope-from ) id 1jvHdC-0007CZ-L9; Tue, 14 Jul 2020 10:53:46 +0100 Date: Tue, 14 Jul 2020 10:53:46 +0100 From: Russell King - ARM Linux admin To: Jarkko Sakkinen Subject: Re: [PATCH 1/3] module: Rename module_alloc() to text_alloc() and move to kernel proper Message-ID: <20200714095346.GA1551@shell.armlinux.org.uk> References: <20200713182030.1418041-1-jarkko.sakkinen@linux.intel.com> <20200713183410.GY1551@shell.armlinux.org.uk> <20200714094928.GA1442951@linux.intel.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200714094928.GA1442951@linux.intel.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200714_055538_738404_F618C5DE X-CRM114-Status: GOOD ( 25.58 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Catalin Marinas , Kefeng Wang , Paul Mackerras , Zong Li , Andi Kleen , Paul Burton , Michael Ellerman , Vincent Whitchurch , Benjamin Herrenschmidt , Petr Mladek , Brian Gerst , Andy Lutomirski , Yonghong Song , Thomas Gleixner , Jiri Kosina , Anup Patel , linux-kernel@vger.kernel.org, Philipp Rudo , Torsten Duwe , Masami Hiramatsu , Andrew Morton , Mark Rutland , "James E.J. Bottomley" , Vincent Chen , "open list:S390" , Joe Lawrence , Helge Deller , John Fastabend , Anil S Keshavamurthy , Andrey Ryabinin , Iurii Zaikin , Andrii Nakryiko , Vasily Gorbik , "moderated list:ARM PORT" , Daniel Axtens , Damien Le Moal , Peter Oberparleiter , Sean Christopherson , Martin KaFai Lau , Song Liu , Paul Walmsley , Heiko Carstens , Alexei Starovoitov , Atish Patra , Will Deacon , Daniel Borkmann , Masahiro Yamada , Nayna Jain , Ley Foon Tan , Christian Borntraeger , Dmitry Vyukov , Sami Tolvanen , "Naveen N. Rao" , Mao Han , Marco Elver , Steven Rostedt , Babu Moger , Borislav Petkov , Greentime Hu , Ben Dooks , Guan Xuetao , Thomas Bogendoerfer , "open list:PARISC ARCHITECTURE" , Jessica Yu , "open list:BPF JIT for MIPS \(32-BIT AND 64-BIT\)" , "David S. Miller" , Thiago Jung Bauermann , Peter Zijlstra , "open list:SPARC + UltraSPARC \(sparc/sparc64\)" , Sandipan Das , "H. Peter Anvin" , Amit Daniel Kachhap , Tiezhu Yang , Miroslav Benes , Jiri Olsa , Ard Biesheuvel , Vincenzo Frascino , Anders Roxell , Sven Schnelle , "maintainer:X86 ARCHITECTURE \(32-BIT AND 64-BIT\)" , "open list:RISC-V ARCHITECTURE" , Mike Rapoport , Ingo Molnar , Albert Ou , "Paul E. McKenney" , Josh Poimboeuf , KP Singh , Gerald Schaefer , Nick Hu , "open list:BPF JIT for MIPS \(32-BIT AND 64-BIT\)" , "open list:MIPS" , Sergey Senozhatsky , Palmer Dabbelt , "open list:LINUX FOR POWERPC \(32-BIT AND 64-BIT\)" Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org On Tue, Jul 14, 2020 at 12:49:28PM +0300, Jarkko Sakkinen wrote: > On Mon, Jul 13, 2020 at 07:34:10PM +0100, Russell King - ARM Linux admin wrote: > > On Mon, Jul 13, 2020 at 09:19:37PM +0300, Jarkko Sakkinen wrote: > > > Rename module_alloc() to text_alloc() and module_memfree() to > > > text_memfree(), and move them to kernel/text.c, which is unconditionally > > > compiled to the kernel proper. This allows kprobes, ftrace and bpf to > > > allocate space for executable code without requiring to compile the modules > > > support (CONFIG_MODULES=y) in. > > > > I'm not sure this is a good idea for 32-bit ARM. The code you are > > moving for 32-bit ARM is quite specific to module use in that it also > > supports allocating from the vmalloc area, where the module code > > knows to add PLT entries. > > > > If the other proposed users of this text_alloc() do not have the logic > > to add PLT entries when branches between kernel code and this > > allocation are not reachable by, e.g. a 26-bit signed offset for 32-bit > > ARM code, then this code is not suitable for that use. > > My intention is to use this in kprobes code in the place of > module_alloc(). I'm not sure why moving this code out of the module > subsystem could possibly break anything. Unfortunately I forgot to add > covere letter to my series. Sending v2 with that to explain my use case > for this. Ah, so you're merely renaming module_alloc() to text_alloc() everywhere? It sounded from the initial patch like you were also converting other users to use module_alloc(). -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last! _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv 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=-5.3 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 B8EB3C433DF for ; Tue, 14 Jul 2020 10:47:02 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 5A7B622203 for ; Tue, 14 Jul 2020 10:47:02 +0000 (UTC) Authentication-Results: mail.kernel.org; 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charset=us-ascii Content-Disposition: inline In-Reply-To: <20200714094928.GA1442951@linux.intel.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-Mailman-Approved-At: Tue, 14 Jul 2020 20:36:21 +1000 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Catalin Marinas , Kefeng Wang , Paul Mackerras , Zong Li , Andi Kleen , Paul Burton , Vincent Whitchurch , Petr Mladek , Brian Gerst , Andy Lutomirski , Yonghong Song , Thomas Gleixner , Jiri Kosina , Anup Patel , linux-kernel@vger.kernel.org, Philipp Rudo , Torsten Duwe , Masami Hiramatsu , Andrew Morton , Mark Rutland , "James E.J. Bottomley" , Vincent Chen , "open list:S390" , Joe Lawrence , Helge Deller , John Fastabend , Anil S Keshavamurthy , Andrey Ryabinin , Iurii Zaikin , Andrii Nakryiko , Vasily Gorbik , "moderated list:ARM PORT" , Daniel Axtens , Damien Le Moal , Peter Oberparleiter , Sean Christopherson , Martin KaFai Lau , Song Liu , Paul Walmsley , Heiko Carstens , Alexei Starovoitov , Atish Patra , Will Deacon , Daniel Borkmann , Masahiro Yamada , Nayna Jain , Ley Foon Tan , Christian Borntraeger , Dmitry Vyukov , Sami Tolvanen , "Naveen N. Rao" , Mao Han , Marco Elver , Steven Rostedt , Babu Moger , Borislav Petkov , Greentime Hu , Ben Dooks , Guan Xuetao , Thomas Bogendoerfer , "open list:PARISC ARCHITECTURE" , Jessica Yu , "open list:BPF JIT for MIPS \(32-BIT AND 64-BIT\)" , "David S. Miller" , Thiago Jung Bauermann , Peter Zijlstra , "open list:SPARC + UltraSPARC \(sparc/sparc64\)" , Sandipan Das , "H. Peter Anvin" , Amit Daniel Kachhap , Tiezhu Yang , Miroslav Benes , Jiri Olsa , Ard Biesheuvel , Vincenzo Frascino , Anders Roxell , Sven Schnelle , "maintainer:X86 ARCHITECTURE \(32-BIT AND 64-BIT\)" , "open list:RISC-V ARCHITECTURE" , Mike Rapoport , Ingo Molnar , Albert Ou , "Paul E. McKenney" , Josh Poimboeuf , KP Singh , Gerald Schaefer , Nick Hu , "open list:BPF JIT for MIPS \(32-BIT AND 64-BIT\)" , "open list:MIPS" , Sergey Senozhatsky , Palmer Dabbelt , "open list:LINUX FOR POWERPC \(32-BIT AND 64-BIT\)" Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Tue, Jul 14, 2020 at 12:49:28PM +0300, Jarkko Sakkinen wrote: > On Mon, Jul 13, 2020 at 07:34:10PM +0100, Russell King - ARM Linux admin wrote: > > On Mon, Jul 13, 2020 at 09:19:37PM +0300, Jarkko Sakkinen wrote: > > > Rename module_alloc() to text_alloc() and module_memfree() to > > > text_memfree(), and move them to kernel/text.c, which is unconditionally > > > compiled to the kernel proper. This allows kprobes, ftrace and bpf to > > > allocate space for executable code without requiring to compile the modules > > > support (CONFIG_MODULES=y) in. > > > > I'm not sure this is a good idea for 32-bit ARM. The code you are > > moving for 32-bit ARM is quite specific to module use in that it also > > supports allocating from the vmalloc area, where the module code > > knows to add PLT entries. > > > > If the other proposed users of this text_alloc() do not have the logic > > to add PLT entries when branches between kernel code and this > > allocation are not reachable by, e.g. a 26-bit signed offset for 32-bit > > ARM code, then this code is not suitable for that use. > > My intention is to use this in kprobes code in the place of > module_alloc(). I'm not sure why moving this code out of the module > subsystem could possibly break anything. Unfortunately I forgot to add > covere letter to my series. Sending v2 with that to explain my use case > for this. Ah, so you're merely renaming module_alloc() to text_alloc() everywhere? It sounded from the initial patch like you were also converting other users to use module_alloc(). -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!