Re: [PATCH v2 1/3] module: Rename module_alloc() to text_alloc() and move to kernel proper

From: Steven Rostedt <rostedt@goodmis.org>
To: Jessica Yu <jeyu@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
	Kefeng Wang <wangkefeng.wang@huawei.com>,
	Paul Mackerras <paulus@samba.org>, Zong Li <zong.li@sifive.com>,
	Andi Kleen <ak@linux.intel.com>,
	Paul Burton <paulburton@kernel.org>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Vincent Whitchurch <vincent.whitchurch@axis.com>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Petr Mladek <pmladek@suse.com>, Brian Gerst <brgerst@gmail.com>,
	Andy Lutomirski <luto@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Jiri Kosina <jkosina@suse.cz>, Anup Patel <anup.patel@wdc.com>,
	linux-kernel@vger.kernel.org, Philipp Rudo <prudo@linux.ibm.com>,
	Torsten Duwe <duwe@lst.de>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Mark Rutland <mark.rutland@arm.com>,
	"James E.J. Bottomley" <James.Bottomley@hansenpartnership.com>,
	Vincent Chen <deanbo422@gmail.com>,
	Omar Sandoval <osandov@fb.com>,
	"open list:S390" <linux-s390@vger.kernel.org>,
	Joe Lawrence <joe.lawrence@redhat.com>,
	Helge Deller <deller@gmx.de>,
	John Fastabend <john.fastabend@gmail.com>,
	Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>,
	Yonghong Song <yhs@fb.com>, Iurii Zaikin <yzaikin@google.com>,
	Andrii Nakryiko <andriin@fb.com>, Thomas Huth <thuth@redhat.com>,
	Vasily Gorbik <gor@linux.ibm.com>,
	"moderated list:ARM PORT" <linux-arm-kernel@lists.infradead.org>,
	Daniel Axtens <dja@axtens.net>,
	Damien Le Moal <damien.lemoal@wdc.com>,
	Martin KaFai Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Heiko Carstens <heiko.carstens@de.ibm.com>,
	Alexei Starovoitov <ast@kernel.org>,
	Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
	Atish Patra <atish.patra@wdc.com>, Will Deacon <will@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Masahiro Yamada <masahiroy@kernel.org>,
	Nayna Jain <nayna@linux.ibm.com>,
	Ley Foon Tan <ley.foon.tan@intel.com>,
	Christian Borntraeger <borntraeger@de.ibm.com>,
	Sami Tolvanen <samitolvanen@google.com>,
	"Naveen N. Rao" <naveen.n.rao@linux.ibm.com>,
	Mao Han <han_mao@c-sky.com>, Marco Elver <elver@google.com>,
	Babu Moger <Babu.Moger@amd.com>, Borislav Petkov <bp@alien8.de>,
	Greentime Hu <green.hu@gmail.com>,
	Ben Dooks <ben-linux@fluff.org>, Guan Xuetao <gxt@pku.edu.cn>,
	Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
	"open list:PARISC ARCHITECTURE" <linux-parisc@vger.kernel.org>,
	"open list:BPF JIT for MIPS \(32-BIT AND 64-BIT\)"
	<bpf@vger.kernel.org>, "David S. Miller" <davem@davemloft.net>,
	Thiago Jung Bauermann <bauerman@linux.ibm.com>,
	Peter Zijlstra <peterz@infradead.org>,
	David Howells <dhowells@redhat.com>,
	"open list:SPARC + UltraSPARC \(sparc/sparc64\)"
	<sparclinux@vger.kernel.org>,
	Sandipan Das <sandipan@linux.ibm.com>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Amit Daniel Kachhap <amit.kachhap@arm.com>,
	Tiezhu Yang <yangtiezhu@loongson.cn>,
	Miroslav Benes <mbenes@suse.cz>, Jiri Olsa <jolsa@redhat.com>,
	Ard Biesheuvel <ardb@kernel.org>,
	Vincenzo Frascino <vincenzo.frascino@arm.com>,
	Anders Roxell <anders.roxell@linaro.org>,
	Sven Schnelle <svens@stackframe.org>,
	"maintainer:X86 ARCHITECTURE \(32-BIT AND 64-BIT\)"
	<x86@kernel.org>, Russell King <linux@armlinux.org.uk>,
	"open list:RISC-V ARCHITECTURE" <linux-riscv@lists.infradead.org>,
	Mike Rapoport <rppt@linux.ibm.com>,
	Ingo Molnar <mingo@redhat.com>, Albert Ou <aou@eecs.berkeley.edu>,
	"Paul E. McKenney" <paulmck@kernel.org>,
	Josh Poimboeuf <jpoimboe@redhat.com>,
	KP Singh <kpsingh@chromium.org>,
	Dmitry Vyukov <dvyukov@google.com>,
	Nick Hu <nickhu@andestech.com>,
	"open list:BPF JIT for MIPS \(32-BIT AND 64-BIT\)"
	<netdev@vger.kernel.org>,
	"open list:MIPS" <linux-mips@vger.kernel.org>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	"open list:LINUX FOR POWERPC \(32-BIT AND 64-BIT\)"
	<linuxppc-dev@lists.ozlabs.org>
Subject: Re: [PATCH v2 1/3] module: Rename module_alloc() to text_alloc() and move to kernel proper
Date: Tue, 14 Jul 2020 11:44:37 -0400	[thread overview]
Message-ID: <20200714114437.7f0025b5@oasis.local.home> (raw)
In-Reply-To: <20200714135651.GA27819@linux-8ccs>

On Tue, 14 Jul 2020 15:56:52 +0200
Jessica Yu <jeyu@kernel.org> wrote:

> As Ard and Will have already explained, the major issue I'm having
> with this is that we're taking module_alloc(), an allocator that was
> originally specific to module loading, and turning it into a generic
> interface to be used by other subsystems. You're pulling in all the
> module loading semantics that vary by architecture and expecting it to
> work as a generic text allocator. I'm not against the existence of a
> generic text_alloc() but I would very much rather that module_alloc()
> be left alone to the module loader and instead work on introducing a
> *separate* generic text_alloc() interface that would work for its
> intended users (kprobes, bpf, etc) and have existing users of
> module_alloc() switch to that instead.

Looks like the consensus is to create a separate text_alloc() that can
be used when modules are not configured in for things like ftrace
dynamic trampolines, and keep module_alloc() untouched.

For those concerned about added unused code for architectures that
don't need text_alloc(), we can always create a config called:
CONFIG_ARCH_NEED_TEXT_ALLOC, and the arch can add that to its list of
kconfigs if it intends to use text_alloc().

-- Steve

_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv