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 67AE23857B88 for ; Thu, 15 Feb 2024 21:39:45 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 67AE23857B88 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=redhat.com ARC-Filter: OpenARC Filter v1.0.0 sourceware.org 67AE23857B88 Authentication-Results: server2.sourceware.org; arc=none smtp.remote-ip=170.10.133.124 ARC-Seal: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1708033186; cv=none; b=eVHddIsEgwmiC1z9s8rMCqA8jXcDyEBOzzVd2BIkuxu3H48HD0vbyk5S650+Nyl7XPWFTeELDb8+d0ckI8drazyUPgPBij07AZPePGNl5O8DEXd3WFkqKYyCUcUapMs7MXh71iNoWDEXibP+Asiwoa4d4m8yvWB78TgaD5KYk8s= ARC-Message-Signature: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1708033186; c=relaxed/simple; bh=1XwtPXERRGsI8YnqoLj/yAOl8wyjdFZyUSSPGISHp28=; h=DKIM-Signature:From:To:Subject:Date:Message-ID:MIME-Version; b=Z5xvfcy9ky/FYVmy7XqHJP7AaFSKWLAwh5R9FffCUWh6Tya4VHLwludHjaTqTvYsbmu7JSAr2R7laF22M7mLRyY/lWaQRl2UiXHdoRnt8GVuVRZJ72M91z4pBZ8bzCLpo9VN9RDVZNU9mS//RDhcCrx0JsOSKR5Rfc36GysmQRw= ARC-Authentication-Results: i=1; server2.sourceware.org DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1708033185; 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=uCi+NffBZGSYdqHpnTOTKDQaarP75RpieOMhOnAlTfs=; b=Qm9NOqf2YLakrg7gEwXsGQkWg+TpCT5TzGdGeYI+fW/2CUAGgaCCLMf6kL8JWig0La16bI UhTQWnaQooMdNpnagUG2hT0Q61W3Ij2n0/sW6v1ctev7wI9ecrolaJwz8pmfBWvez8tX4I 5fOh8Swx/aXcFHpJqF43SCNUMumAarQ= Received: from mimecast-mx02.redhat.com (mx-ext.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-692-UKjkhvzuN1236wVUcm6YSQ-1; Thu, 15 Feb 2024 16:39:39 -0500 X-MC-Unique: UKjkhvzuN1236wVUcm6YSQ-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 4F0A13C28640; Thu, 15 Feb 2024 21:39:39 +0000 (UTC) Received: from oldenburg.str.redhat.com (unknown [10.39.192.50]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 93256492BC6; Thu, 15 Feb 2024 21:39:38 +0000 (UTC) From: Florian Weimer To: "H.J. Lu" Cc: libc-alpha@sourceware.org, goldstein.w.n@gmail.com Subject: Re: [PATCH v5 1/2] x86-64: Save APX and Tile registers in ld.so trampoline References: <20240215203241.1938288-1-hjl.tools@gmail.com> <20240215203241.1938288-2-hjl.tools@gmail.com> <87le7l8lmy.fsf@oldenburg.str.redhat.com> Date: Thu, 15 Feb 2024 22:39:37 +0100 In-Reply-To: <87le7l8lmy.fsf@oldenburg.str.redhat.com> (Florian Weimer's message of "Thu, 15 Feb 2024 22:26:13 +0100") Message-ID: <87bk8h8l0m.fsf@oldenburg.str.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.3 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.9 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain X-Spam-Status: No, score=-5.2 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_H4,RCVD_IN_MSPIKE_WL,SPF_HELO_NONE,SPF_NONE,TXREP,T_SCC_BODY_TEXT_LINE 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: * Florian Weimer: > * H. J. Lu: > >> Add APX registers to STATE_SAVE_MASK so that APX and Tile registers are >> saved in ld.so trampoline. This fixes BZ #31371. > > First APX is confusing? > > What's the impact on xsave_state_size and xsave_state_full_size? > I'm worried that the loader trampoline now overflows small stacks. > We used to have such problems in the past. It adds 8,256 bytes on one AMX-capable machine. This will impact compatibility with existing software. Stack usage is increased even if the application does not use AMX at all. I suggest to use a mechanism like STO_AARCH64_VARIANT_PCS to deal with AMX, and only add the APX flag for now. Thanks, Florian