From patchwork Tue Mar 26 16:36:24 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Rutland X-Patchwork-Id: 13604667 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 48913C54E67 for ; Tue, 26 Mar 2024 16:37:38 +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=K8SxTz54jV8LUU7bG/R3i2pGYVUbEumAcdn7SoPxRkM=; b=U6pZ2j1ujDQlFn MAPEufWzJSNMQ3qF/rU/9ejOLTKrtvadhQj2kEu3aSzhTio9D1Yl/73beUcARDinKPIpTzTXSUYTL aoqrwMjA92MHdBhxEOTtV6kR1gAJzX8lqh/0V3wqGv1G7pEENqEod3mM1ob0M1kDNVfMCGm+17yq0 XhDtQK7OuKtxS7aYfNfDrpvW6EYspUaciV/2qBMChgoIErgKmIm5c0Mx1VZLXH+dbRYaQi45QsKm/ b9WHsZws+ovla0KiwZ3fgEZ/HP9ls6hSm8UcQUq/AJpbbo+ESDhZpru70oaXb9Z5FW2yakBSBKhf7 jP6CBieoyAV0b2H3MClA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1rp9ng-00000005VSe-323q; Tue, 26 Mar 2024 16:37:24 +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 1rp9n5-00000005VBt-2tj3 for linux-arm-kernel@lists.infradead.org; Tue, 26 Mar 2024 16:36:51 +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 B5D101516; Tue, 26 Mar 2024 09:37:20 -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 742E03F694; Tue, 26 Mar 2024 09:36:44 -0700 (PDT) From: Mark Rutland To: linux-kernel@vger.kernel.org Cc: agordeev@linux.ibm.com, anil.s.keshavamurthy@intel.com, aou@eecs.berkeley.edu, bp@alien8.de, catalin.marinas@arm.com, dave.hansen@linux.intel.com, davem@davemloft.net, gor@linux.ibm.com, hca@linux.ibm.com, jarkko@kernel.org, jcalvinowens@gmail.com, linux-arm-kernel@lists.infradead.org, mark.rutland@arm.com, mhiramat@kernel.org, mingo@redhat.com, mpe@ellerman.id.au, naveen.n.rao@linux.ibm.com, palmer@dabbelt.com, paul.walmsley@sifive.com, tglx@linutronix.de, will@kernel.org Subject: [PATCH 4/4] kprobes: Remove core dependency on modules Date: Tue, 26 Mar 2024 16:36:24 +0000 Message-Id: <20240326163624.3253157-5-mark.rutland@arm.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20240326163624.3253157-1-mark.rutland@arm.com> References: <20240326163624.3253157-1-mark.rutland@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240326_093649_696906_A8B5DD69 X-CRM114-Status: GOOD ( 18.26 ) 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 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 Tested-by: Jarkko Sakkinen # arch/riscv --- 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 + 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 */ 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; }