From patchwork Tue Apr 7 03:12:18 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 11477481 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id A5D9492A for ; Tue, 7 Apr 2020 03:12:21 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 73503206B8 for ; Tue, 7 Apr 2020 03:12:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="e13HNkmv" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 73503206B8 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 4FA528E00A2; Mon, 6 Apr 2020 23:12:20 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 483398E0062; Mon, 6 Apr 2020 23:12:20 -0400 (EDT) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3982A8E00A2; Mon, 6 Apr 2020 23:12:20 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0147.hostedemail.com [216.40.44.147]) by kanga.kvack.org (Postfix) with ESMTP id 1F91C8E0062 for ; Mon, 6 Apr 2020 23:12:20 -0400 (EDT) Received: from smtpin01.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id D0491A8C4 for ; Tue, 7 Apr 2020 03:12:19 +0000 (UTC) X-FDA: 76679585598.01.cow01_144e4c5777e5a X-Spam-Summary: 2,0,0,c483f6dec7ba3969,d41d8cd98f00b204,akpm@linux-foundation.org,,RULES_HIT:41:69:355:379:800:960:967:973:988:989:1260:1263:1345:1359:1381:1431:1437:1534:1542:1711:1730:1747:1777:1792:2393:2525:2559:2564:2682:2685:2859:2902:2933:2937:2939:2942:2945:2947:2951:2954:3022:3138:3139:3140:3141:3142:3354:3865:3867:3868:3870:3871:3874:3934:3936:3938:3941:3944:3947:3950:3953:3956:3959:4321:5007:6261:6653:7514:7576:7903:8603:9025:9545:10004:11026:11257:11473:11658:11914:12043:12048:12291:12294:12296:12297:12438:12517:12519:12555:12679:12683:12783:12986:13846:14181:14721:14849:21080:21324:21451:21627:21795:21939:21966:21990:30051:30054:30070,0,RBL:198.145.29.99:@linux-foundation.org:.lbl8.mailshell.net-64.100.201.201 62.2.0.100,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fp,MSBL:0,DNSBL:neutral,Custom_rules:0:0:0,LFtime:1,LUA_SUMMARY:none X-HE-Tag: cow01_144e4c5777e5a X-Filterd-Recvd-Size: 4286 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf09.hostedemail.com (Postfix) with ESMTP for ; Tue, 7 Apr 2020 03:12:19 +0000 (UTC) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (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 6CEF320769; Tue, 7 Apr 2020 03:12:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1586229138; bh=pxwAApX3YCapNVNlP9t0FNEGZ9heLDubxRJxZj+HpFI=; h=Date:From:To:Subject:In-Reply-To:From; b=e13HNkmvGPq4oytqBSVxxuu9KBOD4I+yaxkPNTSpm6VttvayF5IyCuRmHZbP3nikK dp9nC+5MX5dzQcuxSvql/etxr8R9F3mBfIpbCuWg2f9KjFuyCksPUbhBGUlJSNoTHn y+7tlmOOxucTgseo0ZKuYaKE9KgWtAkV1bsxMXuE= Date: Mon, 06 Apr 2020 20:12:18 -0700 From: Andrew Morton To: akpm@linux-foundation.org, andreyknvl@gmail.com, andreyknvl@google.com, elver@google.com, glider@google.com, gregkh@linuxfoundation.org, linux-mm@kvack.org, mm-commits@vger.kernel.org, stern@rowland.harvard.edu, torvalds@linux-foundation.org Subject: [patch 155/166] kcov: use t->kcov_mode as enabled indicator Message-ID: <20200407031218.bSRFhL9BD%akpm@linux-foundation.org> In-Reply-To: <20200406200254.a69ebd9e08c4074e41ddebaf@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Andrey Konovalov Subject: kcov: use t->kcov_mode as enabled indicator Currently kcov_remote_start() and kcov_remote_stop() check t->kcov to find out whether the coverage is already being collected by the current task. Use t->kcov_mode for that instead. This doesn't change the overall behavior in any way, but serves as a preparation for the following softirq coverage collection support patch. Link: http://lkml.kernel.org/r/f70377945d1d8e6e4916cbce871a12303d6186b4.1585233617.git.andreyknvl@google.com Link: http://lkml.kernel.org/r/ee1a1dec43059da5d7664c85c1addc89c4cd58de.1584655448.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov Cc: Alan Stern Cc: Alexander Potapenko Cc: Greg Kroah-Hartman Cc: Marco Elver Cc: Andrey Konovalov Signed-off-by: Andrew Morton --- kernel/kcov.c | 34 ++++++++++++++++++++++++---------- 1 file changed, 24 insertions(+), 10 deletions(-) --- a/kernel/kcov.c~kcov-use-t-kcov_mode-as-enabled-indicator +++ a/kernel/kcov.c @@ -746,26 +746,33 @@ static const struct file_operations kcov * In turns kcov_remote_stop() clears those pointers from task_struct to stop * collecting coverage and copies all collected coverage into the kcov area. */ + +static inline bool kcov_mode_enabled(unsigned int mode) +{ + return (mode & ~KCOV_IN_CTXSW) != KCOV_MODE_DISABLED; +} + void kcov_remote_start(u64 handle) { + struct task_struct *t = current; struct kcov_remote *remote; struct kcov *kcov; + unsigned int mode; void *area; - struct task_struct *t; unsigned int size; - enum kcov_mode mode; int sequence; if (WARN_ON(!kcov_check_handle(handle, true, true, true))) return; if (WARN_ON(!in_task())) return; - t = current; + /* * Check that kcov_remote_start is not called twice * nor called by user tasks (with enabled kcov). */ - if (WARN_ON(t->kcov)) + mode = READ_ONCE(t->kcov_mode); + if (WARN_ON(kcov_mode_enabled(mode))) return; kcov_debug("handle = %llx\n", handle); @@ -863,13 +870,20 @@ static void kcov_move_area(enum kcov_mod void kcov_remote_stop(void) { struct task_struct *t = current; - struct kcov *kcov = t->kcov; - void *area = t->kcov_area; - unsigned int size = t->kcov_size; - int sequence = t->kcov_sequence; + struct kcov *kcov; + unsigned int mode; + void *area; + unsigned int size; + int sequence; - if (!kcov) - return; + mode = READ_ONCE(t->kcov_mode); + barrier(); + if (!kcov_mode_enabled(mode)) + return; + kcov = t->kcov; + area = t->kcov_area; + size = t->kcov_size; + sequence = t->kcov_sequence; kcov_stop(t);