From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by sourceware.org (Postfix) with ESMTPS id 738BD3858C5E for ; Mon, 3 Apr 2023 12:25:35 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 738BD3858C5E Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1680524735; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=PDGrVlNVui0uoS04SbbpyrUnybVctwIyIuVecXciYio=; b=AEINdATH5VvqliuHMNb+nO4XFFcfaHIIHe+ohgiZ/R0BOlRmi87KyOrh07v+fBgGjkOyaS 7XXfWuzNHgDIOaGQQOs0nlHw75IEQBLjXJdVkLuKKWlVPgS6hOfYgQ/olMi1yiwdlM24DB IaLXLV5QqP0QE9QdBVRyV3HuGiJNzSk= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-378-GXrrCiMFN6-8cAYOnzdppQ-1; Mon, 03 Apr 2023 08:25:33 -0400 X-MC-Unique: GXrrCiMFN6-8cAYOnzdppQ-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 9647C101A552; Mon, 3 Apr 2023 12:25:33 +0000 (UTC) Received: from oldenburg.str.redhat.com (unknown [10.39.192.85]) by smtp.corp.redhat.com (Postfix) with ESMTPS id EA2AB1121314; Mon, 3 Apr 2023 12:25:32 +0000 (UTC) From: Florian Weimer To: "H.J. Lu" Cc: libc-alpha@sourceware.org Subject: Re: [PATCH v2] x86: Set FSGSBASE to active if enabled by kernel References: <20230316004254.2507895-1-hjl.tools@gmail.com> Date: Mon, 03 Apr 2023 14:25:31 +0200 In-Reply-To: <20230316004254.2507895-1-hjl.tools@gmail.com> (H. J. Lu's message of "Wed, 15 Mar 2023 17:42:54 -0700") Message-ID: <87jzyt2lvo.fsf@oldenburg.str.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.2 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.3 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain X-Spam-Status: No, score=-4.5 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H2,SPF_HELO_NONE,SPF_NONE,TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: * H. J. Lu: > Linux kernel uses AT_HWCAP2 to indicate if FSGSBASE instructions are > enabled. If the HWCAP2_FSGSBASE bit in AT_HWCAP2 is set, FSGSBASE > instructions can be used in user space. Define dl_check_hwcap2 to set > the FSGSBASE feature to active on Linux when the HWCAP2_FSGSBASE bit is > set. > > Add a test to verify that FSGSBASE is active on current kernels. > NB: This test will fail if the kernel doesn't set the HWCAP2_FSGSBASE > bit in AT_HWCAP2 while fsgsbase shows up in /proc/cpuinfo. This version looks good to me. Reviewed-by: Florian Weimer Thanks, Florian