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 24D25CD1292 for ; Thu, 4 Apr 2024 08:15:33 +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:Subject:Cc:To: From: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=fTYETjQSLXisVWSUw3o6UOai+KiJ1H91gT+picb8kYs=; b=2Fq4v7r5MqHw9q vGp2pCdUr5tMxJGCm6gLaSn0cHMNc9KTZ3ZxkMOh0mtUMwp87SqAq04cq5pPjQ2nrizxm/mouaUaT ZReA8K3s9AaUcclKqjf7i5l4UcrtgmDUe2gcfE0LQpGuXDN96ChYXqwuN08Kj4Eibs5FBZAix7qYX bFhAAR+YKnt7RLpmHdS4ScAkJRssgWecuB9SMWAyuX2+CuDVPSbtzFtFqJJaUeE7Rr749nkEphMvk 1Fnmh1IWjunIZc8VnIJq82d7AY9GXO9f76q2rjPlE8bG9FhNslFAGwhX1GfsYuaFlVMFx4z5VGzXM k2V5o0aR3NcdGte4IQCw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1rsIFh-00000001msG-0TrI; Thu, 04 Apr 2024 08:15:17 +0000 Received: from dfw.source.kernel.org ([2604:1380:4641:c500::1]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1rsIFc-00000001mqx-2jDn for linux-arm-kernel@lists.infradead.org; Thu, 04 Apr 2024 08:15:14 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id 9A65F61616; Thu, 4 Apr 2024 08:15:09 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CD8D4C43390; Thu, 4 Apr 2024 08:15:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1712218509; bh=rDx1Vdvila5gE3tw+63m63a1UWB5kSbNMcwAZPHZbok=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=XuZpFrhowh1PudMG3H4N/XVYh5rgMlxISGhfuM5/psqb8qyYu24VBlBiiAmkF3g55 TtdVxVh/d0A5n1VbDKxDvRTzU7YXP/qduNjvo9Ll/lBzDzsHASy+ZIV3/sThJgkdvU rHpuQPgri0lQ2VU2MVZn0sotkgYTbcpPJVDe07ji1CStlay6P8PfcaJ0n+oxydN6J8 BWfnWHqrYztKF3QPxSUCPWbwaWSJWveddcGj0rLI3ADqDtGgRNHsbVSzNOQyDSmht9 8OJ13lxD0FVgJgUwLCfcUf0JXld7tbJ3edAKa4RosG7jQ5dlXnAFXBQq0MVlxucZkz qhD3wC4N05YXQ== Mime-Version: 1.0 Date: Thu, 04 Apr 2024 11:15:04 +0300 Message-Id: From: "Jarkko Sakkinen" To: "Mark Rutland" , Cc: , , , , , , , , , Subject: Re: [PATCH v2 4/4] kprobes: Remove core dependency on modules X-Mailer: aerc 0.17.0 References: <20240403150154.667649-1-mark.rutland@arm.com> <20240403150154.667649-5-mark.rutland@arm.com> In-Reply-To: <20240403150154.667649-5-mark.rutland@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240404_011512_954562_239DD232 X-CRM114-Status: GOOD ( 30.76 ) 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 Wed Apr 3, 2024 at 6:01 PM EEST, 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 HAVE_KPROBES_ALLOC=n and the core kprobes code allocates > memory using module_alloc(), 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=y when > HAVE_KPROBES_ALLOC=y. > > As of this patch kprobes can be used when MODULES=n on arm64 and > riscv. All other architectures still depend on MODULES, either by virtue > of the core dependency on MODULES when HAVE_KPROBES_ALLOC=n, or by > virtue of an explciit dependency on MODULES in arch code. > > 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/lkml/20240326134616.7691-1-jarkko@kernel.org/ > [Mark: Remove execmem changes, depend on HAVE_KPROBES_ALLOC] > Signed-off-by: Mark Rutland > Cc: Albert Ou > Cc: Anil S Keshavamurthy > Cc: Catalin Marinas > Cc: David S. Miller > Cc: Jarkko Sakkinen > Cc: Masami Hiramatsu > Cc: Naveen N. Rao > Cc: Palmer Dabbelt > Cc: Paul Walmsley > Cc: Will Deacon > --- > arch/Kconfig | 2 +- > kernel/kprobes.c | 46 ++++++++++++++++++++++--------------- > kernel/trace/trace_kprobe.c | 15 ++++++++++-- > 3 files changed, 41 insertions(+), 22 deletions(-) > > diff --git a/arch/Kconfig b/arch/Kconfig > index 85bb59f7b8c07..0df2c88547b3c 100644 > --- a/arch/Kconfig > +++ b/arch/Kconfig > @@ -52,7 +52,7 @@ config GENERIC_ENTRY > > config KPROBES > bool "Kprobes" > - depends on MODULES > + depends on MODULES || HAVE_KPROBES_ALLOC > depends on HAVE_KPROBES > select KALLSYMS > select TASKS_RCU if PREEMPTION > diff --git a/kernel/kprobes.c b/kernel/kprobes.c > index fa2ee4e59eca2..ec4493a41b505 100644 > --- a/kernel/kprobes.c > +++ b/kernel/kprobes.c > @@ -1594,6 +1594,7 @@ static int check_kprobe_address_safe(struct kprobe *p, > goto out; > } > > +#ifdef CONFIG_MODULES > /* > * If the module freed '.init.text', we couldn't insert > * kprobes in there. > @@ -1604,7 +1605,9 @@ static int check_kprobe_address_safe(struct kprobe *p, > *probed_mod = NULL; > ret = -ENOENT; > } > +#endif /* CONFIG_MODULES */ > } > + > out: > preempt_enable(); > jump_label_unlock(); > @@ -2484,24 +2487,6 @@ int kprobe_add_area_blacklist(unsigned long start, unsigned long end) > return 0; > } > > -/* Remove all symbols in given area from kprobe blacklist */ > -static void kprobe_remove_area_blacklist(unsigned long start, unsigned long end) > -{ > - struct kprobe_blacklist_entry *ent, *n; > - > - list_for_each_entry_safe(ent, n, &kprobe_blacklist, list) { > - if (ent->start_addr < start || ent->start_addr >= end) > - continue; > - list_del(&ent->list); > - kfree(ent); > - } > -} > - > -static void kprobe_remove_ksym_blacklist(unsigned long entry) > -{ > - kprobe_remove_area_blacklist(entry, entry + 1); > -} > - > int __weak arch_kprobe_get_kallsym(unsigned int *symnum, unsigned long *value, > char *type, char *sym) > { > @@ -2566,6 +2551,25 @@ static int __init populate_kprobe_blacklist(unsigned long *start, > return ret ? : arch_populate_kprobe_blacklist(); > } > > +#ifdef CONFIG_MODULES > +/* Remove all symbols in given area from kprobe blacklist */ > +static void kprobe_remove_area_blacklist(unsigned long start, unsigned long end) > +{ > + struct kprobe_blacklist_entry *ent, *n; > + > + list_for_each_entry_safe(ent, n, &kprobe_blacklist, list) { > + if (ent->start_addr < start || ent->start_addr >= end) > + continue; > + list_del(&ent->list); > + kfree(ent); > + } > +} > + > +static void kprobe_remove_ksym_blacklist(unsigned long entry) > +{ > + kprobe_remove_area_blacklist(entry, entry + 1); > +} > + > static void add_module_kprobe_blacklist(struct module *mod) > { > unsigned long start, end; > @@ -2662,6 +2666,9 @@ 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 +2733,8 @@ 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 */ > > 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; > } 2/4, 3/4, 4/4: Tested-by: Jarkko Sakkinen # arch/riscv BR, Jarkko _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel