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 4AFAD3858D38 for ; Mon, 6 Feb 2023 14:22:13 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 4AFAD3858D38 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=1675693333; 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=lU1WLVnn1ClCwEwEtYpWg6RRZ6adKD7qTuULRT5Tg+k=; b=NVl10SR2o5f5tqnv+CBiZ/krfcMoJuYqhjX55f3IX6NVL/dO1MlR5Dg6ZdATK6Vbp1daBv GHgKaROUbMeqdsHQfUkaT3UCt4ninV0CJFZNWDHGzGIbicHxIzoN57sEKWKQrQyHfCITC1 mnbFJHGsA0Mmni/PGktSCSmrlCmAioo= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-62-bFNk7Cc-Nv-YhYmr8T2YTA-1; Mon, 06 Feb 2023 09:22:01 -0500 X-MC-Unique: bFNk7Cc-Nv-YhYmr8T2YTA-1 Received: from smtp.corp.redhat.com (int-mx10.intmail.prod.int.rdu2.redhat.com [10.11.54.10]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 92C441C0A583; Mon, 6 Feb 2023 14:22:00 +0000 (UTC) Received: from oldenburg.str.redhat.com (unknown [10.2.16.7]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 1A107492B21; Mon, 6 Feb 2023 14:21:59 +0000 (UTC) From: Florian Weimer To: Stefan Liebler via Libc-alpha Cc: Stefan Liebler Subject: Re: [PATCH] S390: Influence hwcaps/stfle via GLIBC_TUNABLES. References: <20230202135750.1632859-1-stli@linux.ibm.com> Date: Mon, 06 Feb 2023 15:21:58 +0100 In-Reply-To: <20230202135750.1632859-1-stli@linux.ibm.com> (Stefan Liebler via Libc-alpha's message of "Thu, 2 Feb 2023 14:57:50 +0100") Message-ID: <87lelavpq1.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 10.11.54.10 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain X-Spam-Status: No, score=-4.9 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: * Stefan Liebler via Libc-alpha: > This patch enables the option to influence hwcaps and stfle bits used > by the s390 specific ifunc-resolvers. The currently x86-specific > tunable glibc.cpu.hwcaps is also used on s390x to achieve the task. In > addition the user can also set a CPU arch-level like z13 instead of > single HWCAP and STFLE features. > > Note that the tunable only handles the features which are really used > in the IFUNC-resolvers. All others are ignored as the values are only > used inside glibc. Thus we can influence: > - HWCAP_S390_VXRS (z13) > - HWCAP_S390_VXRS_EXT (z14) > - HWCAP_S390_VXRS_EXT2 (z15) > - STFLE_MIE3 (z15) > > The influenced hwcap/stfle-bits are stored in the s390-specific > cpu_features struct which also contains reserved fields for future > usage. > > The ifunc-resolvers and users of stfle bits are adjusted to use the > information from cpu_features struct. > > On 31bit, the ELF_MACHINE_IRELATIVE macro is now also defined. > Otherwise the new ifunc-resolvers segfaults as they depend on > the not yet processed_rtld_global_ro@GLIBC_PRIVATE relocation. > --- I think you are updating all the right places. You should probably push this as the hardware maintainer. Thanks, Florian