From patchwork Wed Apr 3 15:01:54 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Rutland X-Patchwork-Id: 13616300 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 16C81CD1292 for ; Wed, 3 Apr 2024 15:02:33 +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:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=RdvyjPAD4jKE2CqfTOyBjd9GZVDe8ykkrqLDiCz+ZMM=; b=SLqL0KT4zGTEQH nUg4WI0WMpfHnIxAhfdZwJ5I1MMWHMmgxB3jATSS86OiP9MtN908uSAQSlXRssEcn7drDQWwDK8Ep Nk1C5T07P+g4B45U+07aiERTHQwYZD17cBSRstGBLcvgsIuIvizLYnRkLAn1eoFmo/BavXycMKbFJ ZUT5DdjuX9KEWYybOBCgwlLPEdCwcIM4d8BfhQiFpAIiC/tSxwMaCa8GhIKreJqOenUVKZNTmXvO/ t5RkQSKnSM9gzu0KLVpEBzaiRMFFlbY+3r495k/USXMy57bPqpkX3JOZQEVN1BRoaaBf2JGlsHgyM V1T2ds4m8W0k4MlsXsFg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1rs281-0000000GbHS-3cKG; Wed, 03 Apr 2024 15:02:17 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1rs27v-0000000GbCw-3cFq for linux-arm-kernel@lists.infradead.org; Wed, 03 Apr 2024 15:02:13 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 9E98A1595; Wed, 3 Apr 2024 08:02:42 -0700 (PDT) Received: from lakrids.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id F00113F7B4; Wed, 3 Apr 2024 08:02:09 -0700 (PDT) From: Mark Rutland To: linux-kernel@vger.kernel.org Cc: anil.s.keshavamurthy@intel.com, aou@eecs.berkeley.edu, catalin.marinas@arm.com, davem@davemloft.net, jarkko@kernel.org, linux-arm-kernel@lists.infradead.org, mark.rutland@arm.com, mhiramat@kernel.org, naveen.n.rao@linux.ibm.com, palmer@dabbelt.com, paul.walmsley@sifive.com, will@kernel.org Subject: [PATCH v2 4/4] kprobes: Remove core dependency on modules Date: Wed, 3 Apr 2024 16:01:54 +0100 Message-Id: <20240403150154.667649-5-mark.rutland@arm.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20240403150154.667649-1-mark.rutland@arm.com> References: <20240403150154.667649-1-mark.rutland@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240403_080212_014853_0397E1F8 X-CRM114-Status: GOOD ( 21.98 ) 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: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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 Tested-by: Jarkko Sakkinen # arch/riscv --- 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; }