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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 064C7EB64DB for ; Sun, 18 Jun 2023 08:01:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229545AbjFRIBS (ORCPT ); Sun, 18 Jun 2023 04:01:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58940 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229470AbjFRIBR (ORCPT ); Sun, 18 Jun 2023 04:01:17 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1FA0D10D7; Sun, 18 Jun 2023 01:01:16 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id B17EC60F61; Sun, 18 Jun 2023 08:01:15 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7DA1EC433C0; Sun, 18 Jun 2023 08:01:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1687075275; bh=JOdF7gdXvqBjASqKs6SWBkQKDgB3N69nrNaZPukvaeM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=sRSVsUz+8qwPDTD+DbQ8ZGj3oxWbs6Q2yclpQ5oA01FgfO3x99AMq57vy9vTmKGCz zxsNFAk2tsVXc2/ZMKN5WrqHKwwq7cFYa5f3HPOYIxlAVh8JcIK7E8a/4ukOQRZ4nx MkY7brx+YmsqJJOWjKI+esA6758vzynczNeZM28mb8D2036W2Ac3dVaBq4RYIRm2lO UwBKETxVcKwPW5jcSjXTb+3J9p7JSrJABXAw2lEoobsEXKewtbcSu8Iyl/ROefguVb JB6NowqZPjsvgPvrW3+OErG+qxYX7mjk/nhQmoo1FPg/indEYGUiochf7rWuDn85yN s8jpvUG70jw+A== Date: Sun, 18 Jun 2023 11:00:27 +0300 From: Mike Rapoport To: Andy Lutomirski Cc: Linux Kernel Mailing List , Andrew Morton , Catalin Marinas , Christophe Leroy , "David S. Miller" , Dinh Nguyen , Heiko Carstens , Helge Deller , Huacai Chen , Kent Overstreet , Luis Chamberlain , Mark Rutland , Michael Ellerman , Nadav Amit , "Naveen N. Rao" , Palmer Dabbelt , Puranjay Mohan , Rick P Edgecombe , "Russell King (Oracle)" , Song Liu , Steven Rostedt , Thomas Bogendoerfer , Thomas Gleixner , Will Deacon , bpf@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mips@vger.kernel.org, linux-mm@kvack.org, linux-modules@vger.kernel.org, linux-parisc@vger.kernel.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, loongarch@lists.linux.dev, netdev@vger.kernel.org, sparclinux@vger.kernel.org, the arch/x86 maintainers Subject: Re: [PATCH v2 02/12] mm: introduce execmem_text_alloc() and jit_text_alloc() Message-ID: <20230618080027.GA52412@kernel.org> References: <20230616085038.4121892-1-rppt@kernel.org> <20230616085038.4121892-3-rppt@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-trace-kernel@vger.kernel.org On Sat, Jun 17, 2023 at 01:38:29PM -0700, Andy Lutomirski wrote: > On Fri, Jun 16, 2023, at 1:50 AM, Mike Rapoport wrote: > > From: "Mike Rapoport (IBM)" > > > > module_alloc() is used everywhere as a mean to allocate memory for code. > > > > Beside being semantically wrong, this unnecessarily ties all subsystems > > that need to allocate code, such as ftrace, kprobes and BPF to modules > > and puts the burden of code allocation to the modules code. > > > > Several architectures override module_alloc() because of various > > constraints where the executable memory can be located and this causes > > additional obstacles for improvements of code allocation. > > > > Start splitting code allocation from modules by introducing > > execmem_text_alloc(), execmem_free(), jit_text_alloc(), jit_free() APIs. > > > > Initially, execmem_text_alloc() and jit_text_alloc() are wrappers for > > module_alloc() and execmem_free() and jit_free() are replacements of > > module_memfree() to allow updating all call sites to use the new APIs. > > > > The intention semantics for new allocation APIs: > > > > * execmem_text_alloc() should be used to allocate memory that must reside > > close to the kernel image, like loadable kernel modules and generated > > code that is restricted by relative addressing. > > > > * jit_text_alloc() should be used to allocate memory for generated code > > when there are no restrictions for the code placement. For > > architectures that require that any code is within certain distance > > from the kernel image, jit_text_alloc() will be essentially aliased to > > execmem_text_alloc(). > > > > Is there anything in this series to help users do the appropriate > synchronization when the actually populate the allocated memory with > code? See here, for example: This series only factors out the executable allocations from modules and puts them in a central place. Anything else would go on top after this lands. > https://lore.kernel.org/linux-fsdevel/cb6533c6-cea0-4f04-95cf-b8240c6ab405@app.fastmail.com/T/#u -- Sincerely yours, Mike.