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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 0C98BC54E67 for ; Tue, 26 Mar 2024 17:14:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:References:To:From:Subject: Cc:Message-Id:Date:Mime-Version:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=JYXgADg0Vgs2Uu98WHJfunGVYAJFnAYT0ZoArUp+H5s=; b=CSunr8X5hd46nd dSQqbvH4In8X2inpUqCo0rFot3uytkRqiZV0BOXSc1gGeRL/+Vrv2pbXhnxcUfPz5qTRhjtNGcK6E Z93FnfGuMhj8Wa5HbAaAcKTly70gPGBftEYljR7Xum3ric3XAQmemlbeQDyBBqduCycQjMkmxQAy1 /7JrstFMRxskZYRrsUUfK29GvCiU4nHZOVtlPVePRmtg4Tmf4sER4UQsYHU1OqCw0rZ+aNvTVE7f1 /PDzszmg7ILH1eORsGuuanVuK2SR8lYELLyKilS3PR9npPyRuIDIYej24GoAEHk9pYO5UHGqqy6wg 5l4cuwsKvSerMyInUxIQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1rpANO-00000005g6s-1BFB; Tue, 26 Mar 2024 17:14:18 +0000 Received: from sin.source.kernel.org ([145.40.73.55]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1rpAN9-00000005g1r-0nlq for linux-arm-kernel@lists.infradead.org; Tue, 26 Mar 2024 17:14:15 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sin.source.kernel.org (Postfix) with ESMTP id 16961CE0AC3; Tue, 26 Mar 2024 17:13:58 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2C4F4C433F1; Tue, 26 Mar 2024 17:13:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1711473237; bh=AJR5USqJiMDQOJPpOHN5Bf+9uA64buMtfFzhzaUh3jg=; h=Date:Cc:Subject:From:To:References:In-Reply-To:From; b=NlHYV/PfVN+fR+oUL/bR8wrrYkHVzVrwwurW1v0qiQp4Pl3WuqaQJa3gkjg0ZjopU O59LhWiDSS2m1V/OQcpDwvQx7rEAVoANBoyRk9ymFhu0dnjHxnj5FjHPTARuknaKrk tJgqzCgaJuw9AlGJkq0Fm1BLH1b9psVm+WZSJctymRcP3LEDkGgOXAFg0lEBpvQ9sW 4cPgMw57vLzHiwappHT/o3l4dUMrbXqNHgHcH4teUtFD8LP/DcAAOhNT+Z9C7ZuMN6 gw8iDk1b8rQI4DSwjPcU/RauzGlztanbOCMy2JhrfUw5xFCJ64gsLeTch+PNdCuvvI f2tMhXwszhqgw== Mime-Version: 1.0 Date: Tue, 26 Mar 2024 19:13:51 +0200 Message-Id: Cc: , , , , , , , , , , , , , , , , , , Subject: Re: [PATCH 4/4] kprobes: Remove core dependency on modules From: "Jarkko Sakkinen" To: "Mark Rutland" , X-Mailer: aerc 0.17.0 References: <20240326163624.3253157-1-mark.rutland@arm.com> <20240326163624.3253157-5-mark.rutland@arm.com> In-Reply-To: <20240326163624.3253157-5-mark.rutland@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240326_101413_506044_A091F135 X-CRM114-Status: GOOD ( 27.58 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue Mar 26, 2024 at 6:36 PM EET, Mark Rutland wrote: > From: Jarkko Sakkinen > > Tracing with kprobes while running a monolithic kernel is currently > impossible because KPROBES depends on MODULES. While this dependency is > necessary when KPROBES_USE_MODULE_ALLOC=y, all the other module-specific > code only exist to handle the case when MODULES=y, and can be hidden > behind ifdeffery. > > Add the necessary ifdeffery, and remove the dependency on MODULES=N when > KPROBES_USE_MODULE_ALLOC=n. > > Currently this allows kprobes to be used when CONFIG_MODULES=n on arm64 > and riscv, and other architectures can enable support by implementing > their own kprobes_alloc_insn_page() and kprobes_free_insn_page() which > do not depend on MODULES. > > Signed-off-by: Jarkko Sakkinen > Link: https://lore.kernel.org/all/20240326012102.27438-1-jarkko@kernel.org/ > [Mark: Remove execmem changes, depend on !KPROBES_USE_MODULE_ALLOC] > Signed-off-by: Mark Rutland > Cc: Anil S Keshavamurthy > Cc: David S. Miller > Cc: Jarkko Sakkinen > Cc: Masami Hiramatsu > Cc: Naveen N. Rao > --- > arch/Kconfig | 2 +- > kernel/kprobes.c | 12 +++++++++++- > kernel/trace/trace_kprobe.c | 15 +++++++++++++-- > 3 files changed, 25 insertions(+), 4 deletions(-) > > diff --git a/arch/Kconfig b/arch/Kconfig > index 85bb59f7b8c07..cf43de9ffb5b9 100644 > --- a/arch/Kconfig > +++ b/arch/Kconfig > @@ -52,7 +52,7 @@ config GENERIC_ENTRY > > config KPROBES > bool "Kprobes" > - depends on MODULES > + depends on MODULES || !KPROBES_USE_MODULE_ALLOC > depends on HAVE_KPROBES > select KALLSYMS > select TASKS_RCU if PREEMPTION > diff --git a/kernel/kprobes.c b/kernel/kprobes.c > index fa2ee4e59eca2..7c2f0b504cdcb 100644 > --- a/kernel/kprobes.c > +++ b/kernel/kprobes.c > @@ -1582,6 +1582,7 @@ static int check_kprobe_address_safe(struct kprobe *p, > goto out; > } > > +#ifdef CONFIG_MODULES > /* Check if 'p' is probing a module. */ > *probed_mod = __module_text_address((unsigned long) p->addr); > if (*probed_mod) { > @@ -1605,6 +1606,8 @@ static int check_kprobe_address_safe(struct kprobe *p, > ret = -ENOENT; > } > } > +#endif This can be scoped a bit more (see v7 of my patch set). > + > out: > preempt_enable(); > jump_label_unlock(); > @@ -2484,6 +2487,7 @@ int kprobe_add_area_blacklist(unsigned long start, unsigned long end) > return 0; > } > > +#ifdef CONFIG_MODULES > /* Remove all symbols in given area from kprobe blacklist */ > static void kprobe_remove_area_blacklist(unsigned long start, unsigned long end) > { > @@ -2501,6 +2505,7 @@ static void kprobe_remove_ksym_blacklist(unsigned long entry) > { > kprobe_remove_area_blacklist(entry, entry + 1); > } > +#endif /* CONFIG_MODULES */ > > int __weak arch_kprobe_get_kallsym(unsigned int *symnum, unsigned long *value, > char *type, char *sym) > @@ -2566,6 +2571,7 @@ static int __init populate_kprobe_blacklist(unsigned long *start, > return ret ? : arch_populate_kprobe_blacklist(); > } > > +#ifdef CONFIG_MODULES > static void add_module_kprobe_blacklist(struct module *mod) > { > unsigned long start, end; > @@ -2662,6 +2668,9 @@ static int kprobes_module_callback(struct notifier_block *nb, > mutex_unlock(&kprobe_mutex); > return NOTIFY_DONE; > } > +#else > +#define kprobes_module_callback (NULL) > +#endif /* CONFIG_MODULES */ > > static struct notifier_block kprobe_module_nb = { > .notifier_call = kprobes_module_callback, > @@ -2726,7 +2735,8 @@ static int __init init_kprobes(void) > err = arch_init_kprobes(); > if (!err) > err = register_die_notifier(&kprobe_exceptions_nb); > - if (!err) > + > + if (!err && IS_ENABLED(CONFIG_MODULES)) > err = register_module_notifier(&kprobe_module_nb); > > kprobes_initialized = (err == 0); > diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c > index 14099cc17fc9e..c509ba776e679 100644 > --- a/kernel/trace/trace_kprobe.c > +++ b/kernel/trace/trace_kprobe.c > @@ -111,6 +111,7 @@ static nokprobe_inline bool trace_kprobe_within_module(struct trace_kprobe *tk, > return strncmp(module_name(mod), name, len) == 0 && name[len] == ':'; > } > > +#ifdef CONFIG_MODULES > static nokprobe_inline bool trace_kprobe_module_exist(struct trace_kprobe *tk) > { > char *p; > @@ -129,6 +130,9 @@ static nokprobe_inline bool trace_kprobe_module_exist(struct trace_kprobe *tk) > > return ret; > } > +#else > +#define trace_kprobe_module_exist(tk) false /* aka a module never exists */ > +#endif /* CONFIG_MODULES */ > > static bool trace_kprobe_is_busy(struct dyn_event *ev) > { > @@ -670,6 +674,7 @@ static int register_trace_kprobe(struct trace_kprobe *tk) > return ret; > } > > +#ifdef CONFIG_MODULES > /* Module notifier call back, checking event on the module */ > static int trace_kprobe_module_callback(struct notifier_block *nb, > unsigned long val, void *data) > @@ -699,6 +704,9 @@ static int trace_kprobe_module_callback(struct notifier_block *nb, > > return NOTIFY_DONE; > } > +#else > +#define trace_kprobe_module_callback (NULL) > +#endif /* CONFIG_MODULES */ The last two CONFIG_MODULES sections could be combined. This was also in v7. > > static struct notifier_block trace_kprobe_module_nb = { > .notifier_call = trace_kprobe_module_callback, > @@ -1933,8 +1941,11 @@ static __init int init_kprobe_trace_early(void) > if (ret) > return ret; > > - if (register_module_notifier(&trace_kprobe_module_nb)) > - return -EINVAL; > + if (IS_ENABLED(CONFIG_MODULES)) { > + ret = register_module_notifier(&trace_kprobe_module_nb); > + if (ret) > + return -EINVAL; > + } > > return 0; > } Other than lgtm. BR, Jarkko _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel