From patchwork Mon Mar 2 14:25:00 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wang Nan X-Patchwork-Id: 5914161 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 F2D329F380 for ; Mon, 2 Mar 2015 14:56:43 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 127A220220 for ; Mon, 2 Mar 2015 14:56:43 +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 9F1A520221 for ; Mon, 2 Mar 2015 14:56:41 +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 1YSRj6-0004ON-4e; Mon, 02 Mar 2015 14:53:44 +0000 Received: from casper.infradead.org ([2001:770:15f::2]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1YSRbu-0005rj-14 for linux-arm-kernel@bombadil.infradead.org; Mon, 02 Mar 2015 14:46:18 +0000 Received: from szxga02-in.huawei.com ([119.145.14.65]) by casper.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1YSRJG-0008Al-Ni for linux-arm-kernel@lists.infradead.org; Mon, 02 Mar 2015 14:27:05 +0000 Received: from 172.24.2.119 (EHLO lggeml422-hub.china.huawei.com) ([172.24.2.119]) by szxrg02-dlp.huawei.com (MOS 4.3.7-GA FastPath queued) with ESMTP id CHW85031; Mon, 02 Mar 2015 22:26:01 +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 22:25:48 +0800 From: Wang Nan To: , , , , Subject: [RFC PATCH v4 22/34] ftrace: allow search ftrace addr before ftrace fully inited. Date: Mon, 2 Mar 2015 22:25:00 +0800 Message-ID: <1425306312-3437-23-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-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20150302_142703_552061_17213995 X-CRM114-Status: GOOD ( 14.29 ) 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 enables ftrace_location() to be used before ftrace_init(). The first user should be early kprobes, which can insert kprobes to kernel code even before setup_arch() finishes. This patch gives it a chance to determine whether it is probing ftrace entries and allows it do some special treatment. ftrace_cmp_ips_insn() is introduced to make early ftrace_location() behavior consistent with normal ftrace_location(). With existing ftrace_cmp_ips(), searching an address in middle of an instruction will fail, which is inconsistent with ftrace_cmp_recs() used by normal ftrace_location(). With this and previous patch ftrace_location() now is able to be called in and after setup_arch(). Signed-off-by: Wang Nan --- kernel/trace/ftrace.c | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index fa3cdd3..7fa88d0 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1539,6 +1539,8 @@ static unsigned long ftrace_location_range(unsigned long start, unsigned long en return 0; } +static unsigned long ftrace_search_mcount_ip(unsigned long ip); + /** * ftrace_location - return true if the ip giving is a traced location * @ip: the instruction pointer to check @@ -1550,6 +1552,9 @@ static unsigned long ftrace_location_range(unsigned long start, unsigned long en */ unsigned long ftrace_location(unsigned long ip) { + if (unlikely(!ftrace_pages_start)) + return ftrace_search_mcount_ip(ip); + return ftrace_location_range(ip, ip); } @@ -4733,6 +4738,18 @@ static int ftrace_cmp_ips(const void *a, const void *b) return 0; } +static int ftrace_cmp_ips_insn(const void *a, const void *b) +{ + const unsigned long *ipa = a; + const unsigned long *ipb = b; + + if (*ipa >= *ipb + MCOUNT_INSN_SIZE) + return 1; + if (*ipa < *ipb) + return -1; + return 0; +} + static void ftrace_swap_ips(void *a, void *b, int size) { unsigned long *ipa = a; @@ -4770,6 +4787,27 @@ static void ftrace_sort_mcount_area(unsigned long *start, unsigned long *end) kernel_mcount_sorted = true; } +static unsigned long ftrace_search_mcount_ip(unsigned long ip) +{ + extern unsigned long __start_mcount_loc[]; + extern unsigned long __stop_mcount_loc[]; + + unsigned long *mcount_start = __start_mcount_loc; + unsigned long *mcount_end = __stop_mcount_loc; + unsigned long count = mcount_end - mcount_start; + unsigned long *retval; + + if (!kernel_mcount_sorted) + return 0; + + retval = bsearch(&ip, mcount_start, count, + sizeof(unsigned long), ftrace_cmp_ips_insn); + if (!retval) + return 0; + + return ftrace_call_adjust(ip); +} + static int ftrace_process_locs(struct module *mod, unsigned long *start, unsigned long *end)