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=-5.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 D1FBAC4742C for ; Fri, 13 Nov 2020 11:45:14 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 50EF822226 for ; Fri, 13 Nov 2020 11:45:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="Qrto/tE6" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 50EF822226 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=pRaiU15pmqD2PUZpodJ7OPuPnqtiAWOW4b7SV5qNklI=; b=Qrto/tE6QzN5G9axbAuhfhRzA ikiTDmUuHFmW+Oi2sKe6fOf223p3cBDTv8P9+vmEsCsr3g9gJxQ+KNIYVawOUfVXg3RJ5XZy78tWq mhSNHF4CBftMvbC4asfBILyKIZPpQ6g46yM6VW1oZE3k3l95VLyyG8ZPFUZswjJeaaupmM1GzsZnp HRhaJhgStfZrBDJQWhBBr5zoGlT182AwogguO5A4ArYkHk5jPxUslPUoz5Ty8bC48QUzhQ/rFdU83 b1LYeiWt2QDqpn/JFjIF6tw4WhDFuKmVCLL47txpOtGdxS0VaKn+2bfQihpNYQLaXjaY6ohBbVMAj 99HUuqTWw==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kdXVR-00037m-V9; Fri, 13 Nov 2020 11:44:41 +0000 Received: from foss.arm.com ([217.140.110.172]) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kdXVP-00037K-El for linux-arm-kernel@lists.infradead.org; Fri, 13 Nov 2020 11:44:40 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id C0C6914BF; Fri, 13 Nov 2020 03:44:33 -0800 (PST) Received: from [10.37.12.45] (unknown [10.37.12.45]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id D532F3F6CF; Fri, 13 Nov 2020 03:44:30 -0800 (PST) Subject: Re: [PATCH v9 44/44] kselftest/arm64: Check GCR_EL1 after context switch To: Alexander Potapenko , Andrey Konovalov References: From: Vincenzo Frascino Message-ID: Date: Fri, 13 Nov 2020 11:47:35 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201113_064439_601445_977D8A5C X-CRM114-Status: GOOD ( 26.30 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Linux ARM , Marco Elver , Catalin Marinas , Kevin Brodsky , Will Deacon , Branislav Rankov , kasan-dev , LKML , Linux Memory Management List , Dmitry Vyukov , Andrey Ryabinin , Andrew Morton , Evgenii Stepanov Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Alexander, thank you for the review. On 11/12/20 3:59 PM, Alexander Potapenko wrote: > On Tue, Nov 10, 2020 at 11:12 PM Andrey Konovalov wrote: >> >> From: Vincenzo Frascino >> >> This test is specific to MTE and verifies that the GCR_EL1 register >> is context switched correctly. >> >> It spawn 1024 processes and each process spawns 5 threads. Each thread > > Nit: "spawns" > I will fix it in the next iteration. > >> + srand(time(NULL) ^ (pid << 16) ^ (tid << 16)); >> + >> + prctl_tag_mask = rand() % 0xffff; > > Nit: if you want values between 0 and 0xffff you probably want to use > bitwise AND. > The main goal here is to have a good probability of having a different setting to the GCR_EL1 register. Hence the difference in between 0xffff and 0xffff-1 is negligible. Anyway I agree that we should aim to cover all the possible combinations. > >> + >> +int execute_test(pid_t pid) >> +{ >> + pthread_t thread_id[MAX_THREADS]; >> + int thread_data[MAX_THREADS]; >> + >> + for (int i = 0; i < MAX_THREADS; i++) >> + pthread_create(&thread_id[i], NULL, >> + execute_thread, (void *)&pid); > > It might be simpler to call getpid() in execute_thread() instead. > Yes it might, but I would like to avoid another syscall if I can. >> +int mte_gcr_fork_test() >> +{ >> + pid_t pid[NUM_ITERATIONS]; >> + int results[NUM_ITERATIONS]; >> + pid_t cpid; >> + int res; >> + >> + for (int i = 0; i < NUM_ITERATIONS; i++) { >> + pid[i] = fork(); >> + >> + if (pid[i] == 0) { > > pid[i] isn't used anywhere else. Did you want to keep the pids to > ensure that all children finished the work? > If not, we can probably go with a scalar here. > Yes, I agree, I had some debug code making use of it, but I removed it in the end. > >> + for (int i = 0; i < NUM_ITERATIONS; i++) { >> + wait(&res); >> + >> + if(WIFEXITED(res)) >> + results[i] = WEXITSTATUS(res); >> + else >> + --i; > > Won't we get stuck in this loop if fork() returns -1 for one of the processes? > Yes I agree, I forgot to check a condition. We should abort the test in such a case returning KSFT_FAIL directly. >> + } >> + >> + for (int i = 0; i < NUM_ITERATIONS; i++) >> + if (results[i] == KSFT_FAIL) >> + return KSFT_FAIL; >> + >> + return KSFT_PASS; >> +} >> + > > -- Regards, Vincenzo _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel