[email protected]>, Jarkko Sakkinen <[email protected]>, Sami Tolvanen <[email protected]>, "Naveen N. Rao" <[email protected]>, Marco Elver <[email protected]>, Kees Cook <[email protected]>, Steven Rostedt <[email protected]>, Nathan Chancellor <[email protected]>, "Russell King \(Oracle\)" <[email protected]>, Mark Brown <[email protected]>, Borislav Petkov <[email protected]>, Alexander Egorenkov <[email protected]>, Thomas Bogendoerfer <[email protected]>, Parisc List <[email protected]>, Nathaniel McCallum <[email protected]>, Dmitry Torokhov <[email protected]>, "David S. Miller" <[email protected]>, "Kirill A. Shutemov" <[email protected]>, Tobias Huschle <[email protected]>, "Peter Zijlstra \(Intel\)" <[email protected]>, "H. Peter Anvin" <[email protected]>, sparclinux <[email protected]>, Tiezhu Yang <[email protected]>, Miroslav Benes <[email protected]>, Chen Zhongjin <chenzhongjin@hu awei.com>, Ard Biesheuvel <[email protected]>, the arch/x86 maintainers <[email protected]>, Russell King <[email protected]>, linux-riscv <[email protected]>, Ingo Molnar <[email protected]>, Aaron Tomlin <[email protected]>, Albert Ou <[email protected]>, Heiko Carstens <[email protected]>, Liao Chang <[email protected]>, Paul Walmsley <[email protected]>, Josh Poimboeuf <[email protected]>, Thomas Richter <[email protected]>, "open list:BROADCOM NVRAM DRIVER" <[email protected]>, Changbin Du <[email protected]>, Palmer Dabbelt <[email protected]>, linuxppc-dev <[email protected]>, [email protected] Errors-To: [email protected] Sender: "Linuxppc-dev" <[email protected]>
On Wed, Jun 08, 2022 at 11:21:15PM +0900, Masami Hiramatsu wrote: > Hi Jarkko, > > On Wed, 8 Jun 2022 08:25:38 +0300 > Jarkko Sakkinen <[email protected]> wrote: > > > On Wed, Jun 08, 2022 at 10:35:42AM +0800, Guo Ren wrote: > > > . > > > > > > On Wed, Jun 8, 2022 at 8:02 AM Jarkko Sakkinen <[email protected]> wrote: > > > > > > > > Tracing with kprobes while running a monolithic kernel is currently > > > > impossible because CONFIG_KPROBES is dependent of CONFIG_MODULES. This > > > > dependency is a result of kprobes code using the module allocator for > > > > the > > > > trampoline code. > > > > > > > > Detaching kprobes from modules helps to squeeze down the user space, > > > > e.g. when developing new core kernel features, while still having all > > > > the nice tracing capabilities. > > > > > > > > For kernel/ and arch/*, move module_alloc() and module_memfree() to > > > > module_alloc.c, and compile as part of vmlinux when either > > > > CONFIG_MODULES > > > > or CONFIG_KPROBES is enabled. In addition, flag kernel module specific > > > > code with CONFIG_MODULES. > > > > > > > > As the result, kprobes can be used with a monolithic kernel. > > > It's strange when MODULES is n, but vmlinux still obtains module_alloc. > > > > > > Maybe we need a kprobe_alloc, right? > > > > Perhaps not the best name but at least it documents the fact that > > they use the same allocator. > > > > Few years ago I carved up something "half-way there" for kprobes, > > and I used the name text_alloc() [*]. > > > > [*] > > https://lore.kernel.org/all/[email protected]/ > > > > Yeah, I remember that. Thank you for updating your patch! > I think the idea (split module_alloc() from CONFIG_MODULE) is good to me. > If module support maintainers think this name is not good, you may be > able to rename it as text_alloc() and make the module_alloc() as a > wrapper of it. > > Acked-by: Masami Hiramatsu (Google) <[email protected]> > for kprobe side. Thanks a lot! If I split that code into its own patch with no code changes, can I attach this to the patch? I.e. most likely I'll split arch's into their own patches. > Thank you, > > -- > Masami Hiramatsu (Google) <[email protected]> BR, Jarkko
