From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754748AbbCBO0O (ORCPT ); Mon, 2 Mar 2015 09:26:14 -0500 Received: from szxga03-in.huawei.com ([119.145.14.66]:4438 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754682AbbCBO0I (ORCPT ); Mon, 2 Mar 2015 09:26:08 -0500 From: Wang Nan To: , , , , CC: , , , 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 Content-Type: text/plain 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 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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); -- 1.8.4