From patchwork Wed Jan 7 07:36:04 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wang Nan X-Patchwork-Id: 5583061 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id D16279F357 for ; Wed, 7 Jan 2015 07:50:55 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id EA4202025B for ; Wed, 7 Jan 2015 07:50:54 +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 1E4CE20263 for ; Wed, 7 Jan 2015 07:50:54 +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 1Y8lL0-0000hG-R1; Wed, 07 Jan 2015 07:47:30 +0000 Received: from szxga02-in.huawei.com ([119.145.14.65]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1Y8lFY-0004Fc-PB for linux-arm-kernel@lists.infradead.org; Wed, 07 Jan 2015 07:41:54 +0000 Received: from 172.24.2.119 (EHLO lggeml426-hub.china.huawei.com) ([172.24.2.119]) by szxrg02-dlp.huawei.com (MOS 4.3.7-GA FastPath queued) with ESMTP id CFA94060; Wed, 07 Jan 2015 15:41:15 +0800 (CST) Received: from kernel-host.huawei (10.107.197.247) by lggeml426-hub.china.huawei.com (10.72.61.36) with Microsoft SMTP Server id 14.3.158.1; Wed, 7 Jan 2015 15:41:06 +0800 From: Wang Nan To: , , , , , , , , Subject: [RFC PATCH 10/11] kprobes: enable 'ekprobe=' cmdline option for early kprobes. Date: Wed, 7 Jan 2015 15:36:04 +0800 Message-ID: <1420616164-43153-1-git-send-email-wangnan0@huawei.com> X-Mailer: git-send-email 1.8.4 In-Reply-To: <1420616086-42692-1-git-send-email-wangnan0@huawei.com> References: <1420616086-42692-1-git-send-email-wangnan0@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.107.197.247] X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20150106_234153_215932_955F5852 X-CRM114-Status: GOOD ( 10.69 ) X-Spam-Score: -0.7 (/) Cc: 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 the basic idea of usage of early 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. Signed-off-by: Wang Nan --- kernel/kprobes.c | 71 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 71 insertions(+) diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 9c3ea9b..73f9b7f 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -2611,8 +2611,79 @@ convert_early_kprobes(void) hlist_for_each_entry_safe(p, tmp, &early_kprobe_hlist, hlist) convert_early_kprobe(p); }; + +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; + err = register_kprobe(kp); + if (err) { + pr_err("early kprobe: register early kprobe %s failed\n", p); + ek_free_early_kprobe_setup(kp); + } + return 0; +} #else static int register_early_kprobe(struct kprobe *p) { return -ENOSYS; } static int ek_free_early_kprobe(struct early_kprobe_slot *slot) { return 0; } static void convert_early_kprobes(void) {}; + +static int __init early_kprobe_setup(char *p) +{ + return 0; +} #endif + +early_param("ekprobe", early_kprobe_setup);