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=-17.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 EDE28C4743C for ; Wed, 23 Jun 2021 17:47:11 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 B9D50611AC for ; Wed, 23 Jun 2021 17:47:11 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B9D50611AC 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-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=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=KW47mgYWMzQP/95bUQI9AAG4zfLWReoHxuXfBQMYyvs=; b=xYuMrCsn7Xlf8J RgLnHsCJwOmCI/C/9Y+s/IGBt+4xQB7E+m4SPYR3K1BpgZ33eeL+uIRuVu6lo73zx4KkjUbnUQ31h NZzxRAXiBX7DcFmK3uWN9rvET74wijs5GeO2YmwFhDUr5C2+kF2LDOhTGTnMxLbmPZzsoMWpN+sOX zlsSjCu6/+O0/4Op88RaV4zlLf5YIXSH1LKLbdaVTU/kCQJiegJ89k7YUwIiGdBQFxXrrGlGlxfG4 6cFSpUHowX7E50GvsSLIQvEBcrsB1LsQrsL15oWAwTqWI3bDUD4IwxeB73uiY7J7Qf9rl9Ui97Qa1 7SoItpRJt5xfiRkB0XZw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1lw6vi-00BUkh-Uo; Wed, 23 Jun 2021 17:44:51 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1lw6qs-00BRkw-6S for linux-arm-kernel@lists.infradead.org; Wed, 23 Jun 2021 17:39:51 +0000 Received: by mail.kernel.org (Postfix) with ESMTPSA id 5EC9860231; Wed, 23 Jun 2021 17:39:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1624469989; bh=WY4ziB2sQKmBP3QQwTK/wK5acZZqfqz7ssWP+f/5BRA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=a2mPSeYyjRSUnthqCX/O/cPGaIDg7Pke1/5doMxy9BlJNNm3Xeq/TmNtrQjpFxoxd DHuV9S4z1H1YE4i2ddI5JNvfIdjJqFnbRLExezfofrtiphblBRdRE7llgyASXJMEMr 4yRSWlQBymdy5ZWgUcJNG9k++pBJgByJo8VwwSDLbQiirjBoSJoGOIj255VvuYkqpE sguxQNisF6kUkJg8oz/6wDnNa1sflWK5pdNNLsq+GQXBBXJJyNmbP/oClYDlbPkoig 5pWMY1sW+uFF+fiMR19bsEuZ7RQYkJk4w66FiTddqlTVHdKyiYmiYH1n6YvhxjibYC 8sgGiKzqrBiPw== From: Will Deacon To: linux-arm-kernel@lists.infradead.org Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, Will Deacon , Catalin Marinas , Marc Zyngier , Greg Kroah-Hartman , Peter Zijlstra , Morten Rasmussen , Qais Yousef , Suren Baghdasaryan , Quentin Perret , Tejun Heo , Johannes Weiner , Ingo Molnar , Juri Lelli , Vincent Guittot , "Rafael J. Wysocki" , Dietmar Eggemann , Daniel Bristot de Oliveira , Valentin Schneider , Mark Rutland , kernel-team@android.com Subject: [PATCH v10 13/16] arm64: Advertise CPUs capable of running 32-bit applications in sysfs Date: Wed, 23 Jun 2021 18:38:45 +0100 Message-Id: <20210623173848.318-14-will@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210623173848.318-1-will@kernel.org> References: <20210623173848.318-1-will@kernel.org> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210623_103950_363082_BC38D447 X-CRM114-Status: GOOD ( 12.81 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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 Since 32-bit applications will be killed if they are caught trying to execute on a 64-bit-only CPU in a mismatched system, advertise the set of 32-bit capable CPUs to userspace in sysfs. Reviewed-by: Greg Kroah-Hartman Reviewed-by: Catalin Marinas Signed-off-by: Will Deacon --- .../ABI/testing/sysfs-devices-system-cpu | 9 +++++++++ arch/arm64/kernel/cpufeature.c | 19 +++++++++++++++++++ 2 files changed, 28 insertions(+) diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu index fe13baa53c59..899377b2715a 100644 --- a/Documentation/ABI/testing/sysfs-devices-system-cpu +++ b/Documentation/ABI/testing/sysfs-devices-system-cpu @@ -494,6 +494,15 @@ Description: AArch64 CPU registers 'identification' directory exposes the CPU ID registers for identifying model and revision of the CPU. +What: /sys/devices/system/cpu/aarch32_el0 +Date: May 2021 +Contact: Linux ARM Kernel Mailing list +Description: Identifies the subset of CPUs in the system that can execute + AArch32 (32-bit ARM) applications. If present, the same format as + /sys/devices/system/cpu/{offline,online,possible,present} is used. + If absent, then all or none of the CPUs can execute AArch32 + applications and execve() will behave accordingly. + What: /sys/devices/system/cpu/cpu#/cpu_capacity Date: December 2016 Contact: Linux kernel mailing list diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 2f9fe57ead97..23eaa7f06f76 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -67,6 +67,7 @@ #include #include #include +#include #include #include #include @@ -1319,6 +1320,24 @@ const struct cpumask *system_32bit_el0_cpumask(void) return cpu_possible_mask; } +static ssize_t aarch32_el0_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + const struct cpumask *mask = system_32bit_el0_cpumask(); + + return sysfs_emit(buf, "%*pbl\n", cpumask_pr_args(mask)); +} +static const DEVICE_ATTR_RO(aarch32_el0); + +static int __init aarch32_el0_sysfs_init(void) +{ + if (!allow_mismatched_32bit_el0) + return 0; + + return device_create_file(cpu_subsys.dev_root, &dev_attr_aarch32_el0); +} +device_initcall(aarch32_el0_sysfs_init); + static bool has_32bit_el0(const struct arm64_cpu_capabilities *entry, int scope) { if (!has_cpuid_feature(entry, scope)) -- 2.32.0.93.g670b81a890-goog _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel