From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 73A9BC6786F for ; Sat, 3 Nov 2018 16:04:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 30BFE20833 for ; Sat, 3 Nov 2018 16:04:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="mADoE8KH" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 30BFE20833 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728614AbeKDBPk (ORCPT ); Sat, 3 Nov 2018 21:15:40 -0400 Received: from mail.kernel.org ([198.145.29.99]:44248 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728334AbeKDBPk (ORCPT ); Sat, 3 Nov 2018 21:15:40 -0400 Received: from localhost.localdomain (NE2965lan1.rev.em-net.ne.jp [210.141.244.193]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C36EF2081F; Sat, 3 Nov 2018 16:03:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1541261037; bh=aD6IZun8bbTzEqBVoREVoJxkE5xOrxPrEYEw++c+ikg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:In-Reply-To: References:From; b=mADoE8KHyJ7B4p9eGBEz3MeNj4eq8SIJ280gKiPMbyuxEySHrpoNC+l5Lei89K0a2 WlQ6AmZs982xK9wyjkS5jtkYFOQ46nbnlpMcKQRyn05KBaAircqoiknsxKqwCIxvh0 2ceeMvdcRcIgYmGhgW+LXOb5TBG8aIWLpyc2f+ME= From: Masami Hiramatsu To: Steven Rostedt Cc: Masami Hiramatsu , linux-kernel@vger.kernel.org Subject: [RFC PATCH] tracing/kprobes: Avoid parsing symbol+offset when updating arguments Date: Sun, 4 Nov 2018 01:03:34 +0900 Message-Id: <154126101356.14912.1379688281618914741.stgit@devbox> X-Mailer: git-send-email 2.13.6 In-Reply-To: <20181103205448.15b667077e0b72fcd6147239@kernel.org> References: <20181103205448.15b667077e0b72fcd6147239@kernel.org> In-Reply-To: <20181103205448.15b667077e0b72fcd6147239@kernel.org> References: <20181103205448.15b667077e0b72fcd6147239@kernel.org> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Introduce symbol_offset data structure for avoiding symbol+offset parsing when updating arguments. For kprobe events, "@symbol+offset" is supported, that requires to be updated when new module is loaded because @symbol address can be solved at that point. Currently kprobe events saves the "symbol+offset" string and parse it repeatedly, but that is inefficient. This introduces symbol_offset data structure which can save the offset and symbol separated, so that we don't need to parse it anymore. Signed-off-by: Masami Hiramatsu --- kernel/trace/trace_probe.c | 49 +++++++++++++++++++++++++------------------- kernel/trace/trace_probe.h | 7 +++++- 2 files changed, 34 insertions(+), 22 deletions(-) diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c index bd30e9398d2a..0a3af7d6e133 100644 --- a/kernel/trace/trace_probe.c +++ b/kernel/trace/trace_probe.c @@ -201,6 +201,26 @@ static int parse_probe_vars(char *arg, const struct fetch_type *t, return ret; } +static struct symbol_offset *allocate_symbol_offset(char *sym_offs_str) +{ + int ret; + long offset = 0; + struct symbol_offset *sof; + + ret = traceprobe_split_symbol_offset(sym_offs_str, &offset); + if (ret) + return ERR_PTR(ret); + + sof = kzalloc(sizeof(struct symbol_offset) + strlen(sym_offs_str) + 1, + GFP_KERNEL); + if (!sof) + return ERR_PTR(-ENOMEM); + + sof->offset = offset; + strcpy(sof->symbol, sym_offs_str); + return sof; +} + /* Recursive argument parser */ static int parse_probe_arg(char *arg, const struct fetch_type *type, @@ -253,9 +273,9 @@ parse_probe_arg(char *arg, const struct fetch_type *type, /* Preserve symbol for updating */ code->op = FETCH_NOP_SYMBOL; - code->data = kstrdup(arg + 1, GFP_KERNEL); - if (!code->data) - return -ENOMEM; + code->symoffs = allocate_symbol_offset(arg + 1); + if (IS_ERR(code->symoffs)) + return PTR_ERR(code->symoffs); if (++code == end) return -E2BIG; @@ -483,7 +503,7 @@ int traceprobe_parse_probe_arg(char *arg, ssize_t *size, if (ret) { for (code = tmp; code < tmp + FETCH_INSN_MAX; code++) if (code->op == FETCH_NOP_SYMBOL) - kfree(code->data); + kfree(code->symoffs); } kfree(tmp); @@ -513,7 +533,7 @@ void traceprobe_free_probe_arg(struct probe_arg *arg) while (code && code->op != FETCH_OP_END) { if (code->op == FETCH_NOP_SYMBOL) - kfree(code->data); + kfree(code->symoffs); code++; } kfree(arg->code); @@ -525,31 +545,18 @@ void traceprobe_free_probe_arg(struct probe_arg *arg) int traceprobe_update_arg(struct probe_arg *arg) { struct fetch_insn *code = arg->code; - long offset; - char *tmp; - char c; - int ret = 0; while (code && code->op != FETCH_OP_END) { if (code->op == FETCH_NOP_SYMBOL) { if (code[1].op != FETCH_OP_IMM) return -EINVAL; - tmp = strpbrk(code->data, "+-"); - if (tmp) - c = *tmp; - ret = traceprobe_split_symbol_offset(code->data, - &offset); - if (ret) - return ret; - code[1].immediate = - (unsigned long)kallsyms_lookup_name(code->data); - if (tmp) - *tmp = c; + (unsigned long)kallsyms_lookup_name( + code->symoffs->symbol); if (!code[1].immediate) return -ENOENT; - code[1].immediate += offset; + code[1].immediate += code->symoffs->offset; } code++; } diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h index 974afc1a3e73..942424d05427 100644 --- a/kernel/trace/trace_probe.h +++ b/kernel/trace/trace_probe.h @@ -103,6 +103,11 @@ enum fetch_op { FETCH_NOP_SYMBOL, /* Unresolved Symbol holder */ }; +struct symbol_offset { + long offset; + char symbol[]; +}; + struct fetch_insn { enum fetch_op op; union { @@ -117,7 +122,7 @@ struct fetch_insn { unsigned char rshift; }; unsigned long immediate; - void *data; + struct symbol_offset *symoffs; }; };