From patchwork Mon Mar 2 14:25:10 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wang Nan X-Patchwork-Id: 5914081 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id A4B7EBF6C3 for ; Mon, 2 Mar 2015 14:49:43 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id C8528201FB for ; Mon, 2 Mar 2015 14:49:42 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 60183201FA for ; Mon, 2 Mar 2015 14:49:41 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1YSRb9-0005Sa-4w; Mon, 02 Mar 2015 14:45:31 +0000 Received: from merlin.infradead.org ([2001:4978:20e::2]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1YSRJL-00047E-Ca for linux-arm-kernel@bombadil.infradead.org; Mon, 02 Mar 2015 14:27:07 +0000 Received: from szxga03-in.huawei.com ([119.145.14.66]) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1YSRJI-0003ST-6Y for linux-arm-kernel@lists.infradead.org; Mon, 02 Mar 2015 14:27:06 +0000 Received: from 172.24.2.119 (EHLO lggeml422-hub.china.huawei.com) ([172.24.2.119]) by szxrg03-dlp.huawei.com (MOS 4.4.3-GA FastPath queued) with ESMTP id BCM87891; Mon, 02 Mar 2015 22:26:04 +0800 (CST) Received: from kernel-host.huawei (10.107.197.247) by lggeml422-hub.china.huawei.com (10.72.61.32) with Microsoft SMTP Server id 14.3.158.1; Mon, 2 Mar 2015 22:25:56 +0800 From: Wang Nan To: , , , , Subject: [RFC PATCH v4 32/34] early kprobes: enable 'ekprobe=' cmdline option for early kprobes. Date: Mon, 2 Mar 2015 22:25:10 +0800 Message-ID: <1425306312-3437-33-git-send-email-wangnan0@huawei.com> X-Mailer: git-send-email 1.8.4 In-Reply-To: <1425306312-3437-1-git-send-email-wangnan0@huawei.com> References: <1425306312-3437-1-git-send-email-wangnan0@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.107.197.247] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A020204.54F472FD.02A4, ss=1, re=0.001, recu=0.000, reip=0.000, cl=1, cld=1, fgs=0, ip=0.0.0.0, so=2013-05-26 15:14:31, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: 5faada5fb584f333d98d540b72a4d718 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20150302_092705_011577_6D055857 X-CRM114-Status: GOOD ( 15.09 ) X-Spam-Score: -4.2 (----) Cc: x86@kernel.org, lizefan@huawei.com, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This patch shows a very rough usage of arly kprobes. By adding kernel cmdline options such as 'ekprobe=__alloc_pages_nodemask' or 'ekprobe=0xc00f3c2c', early kprobes are installed. When the probed instructions get hit, a message is printed. This patch is only a sample. I'll drop it in future. Signed-off-by: Wang Nan --- kernel/kprobes.c | 84 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 84 insertions(+) diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 95754f6..56fb8c8 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -2224,9 +2224,12 @@ static struct notifier_block kprobe_module_nb = { .priority = 0 }; +static LIST_HEAD(cmdline_early_kprobes_list); + void init_kprobes_early(void) { int i, err = 0; + struct kprobe *early_kp, *tmp; /* FIXME allocate the probe table, currently defined statically */ /* initialize all list heads */ @@ -2270,6 +2273,16 @@ void init_kprobes_early(void) if (!err) init_test_probes(); #endif + + list_for_each_entry_safe(early_kp, tmp, &cmdline_early_kprobes_list, list) { + int ret; + + list_del(&early_kp->list); + INIT_LIST_HEAD(&early_kp->list); + ret = register_kprobe(early_kp); + printk("early kprobe: register early kprobe at %p: result = %d\n", + early_kp->addr, ret); + } } static int __init init_kprobes(void) @@ -2724,3 +2737,74 @@ void init_kprobes_on_ftrace(void) convert_early_kprobes_on_ftrace(); } #endif + +#ifdef CONFIG_EARLY_KPROBES +static int early_kprobe_pre_handler(struct kprobe *p, struct pt_regs *regs) +{ + const char *sym = NULL; + char *modname, namebuf[KSYM_NAME_LEN]; + unsigned long offset = 0; + + sym = kallsyms_lookup((unsigned long)p->addr, NULL, + &offset, &modname, namebuf); + if (sym) + pr_info("Hit early kprobe at %s+0x%lx%s%s\n", + sym, offset, + (modname ? " " : ""), + (modname ? modname : "")); + else + pr_info("Hit early kprobe at %p\n", p->addr); + return 0; +} + +DEFINE_EKPROBE_ALLOC_OPS(struct kprobe, early_kprobe_setup, static); +static int __init early_kprobe_setup(char *p) +{ + unsigned long long addr; + struct kprobe *kp; + int len = strlen(p); + int err; + + if (len <= 0) { + pr_err("early kprobe: wrong param: %s\n", p); + return 0; + } + + if ((p[0] == '0') && (p[1] == 'x')) { + err = kstrtoull(p, 16, &addr); + if (err) { + pr_err("early kprobe: wrong address: %p\n", p); + return 0; + } + } else { + addr = kallsyms_lookup_name(p); + if (!addr) { + pr_err("early kprobe: wrong symbol: %s\n", p); + return 0; + } + } + + if ((addr < (unsigned long)_text) || + (addr >= (unsigned long)_etext)) + pr_err("early kprobe: address of %p out of range\n", p); + + kp = ek_alloc_early_kprobe_setup(); + if (kp == NULL) { + pr_err("early kprobe: no enough early kprobe slot\n"); + return 0; + } + kp->addr = (void *)(unsigned long)(addr); + kp->pre_handler = early_kprobe_pre_handler; + + list_add(&kp->list, &cmdline_early_kprobes_list); + + return 0; +} +#else +static int __init early_kprobe_setup(char *p) +{ + return 0; +} +#endif + +early_param("ekprobe", early_kprobe_setup);