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 [170.10.129.124]) by sourceware.org (Postfix) with ESMTPS id BCD733858D1E for ; Mon, 13 Mar 2023 13:59:39 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org BCD733858D1E 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=1678715979; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=xA8mxIgSgcdcwXzbLEKWKBhjZUWutoYUV+HSS5rvhh4=; b=JMs+P8LYvpW/qgjqfHEFgn/VCidOkgKsY2C2mOqOBSNnvCj6saeRK6MmVdDOyfjI/Uu3sT 43k9R3D2WB+JXxf0s4e3NIfxlWCYIeVSKEQASKiIxm+UKh74WGLBPuhxa5/O37xq+/7rGF w8JFsSBSuP+TFvOWBziRF+jrGY1DPBU= 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-45-eU590iG8OyCfqHA6zbzoiQ-1; Mon, 13 Mar 2023 09:59:36 -0400 X-MC-Unique: eU590iG8OyCfqHA6zbzoiQ-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 3FE742932488; Mon, 13 Mar 2023 13:59:29 +0000 (UTC) Received: from oldenburg.str.redhat.com (unknown [10.2.16.22]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 4DAA32166B26; Mon, 13 Mar 2023 13:59:28 +0000 (UTC) From: Florian Weimer To: Jan Kratochvil Cc: Adhemerval Zanella Netto , libc-alpha@sourceware.org, Anton Kozlov Subject: Re: [PATCH] RFC: Provide a function to reset IFUNC PLTs References: <87v8jdq7ht.fsf@oldenburg.str.redhat.com> <2659aadc-6518-cc0e-d103-84eafcbdc3f9@linaro.org> Date: Mon, 13 Mar 2023 14:59:26 +0100 In-Reply-To: (Jan Kratochvil's message of "Thu, 9 Mar 2023 19:32:24 +0800") Message-ID: <87sfe8rbup.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 10.11.54.6 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable 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: * Jan Kratochvil: > On Wed, 08 Mar 2023 21:04:59 +0800, Adhemerval Zanella Netto wrote: >> But as Florian has said, fixing on glibc won't work consistently on othe= r >> libraries that uses cpuid instruction. > > In Java world the other libraries (in general, there are some JNI excepti= ons) > do not matter as they are a Java code JIT-compiled by JVM. That's not really true for GUI applications, which use quite a few system libraries. Even in headless applications, font rendering code may be loaded, say for PDF generation. If system versions are used, that pulls in compression libraries and PCRE, and those tend to have CPUID-based switching, too (but perhaps not in the form of IFUNC resolvers). This is just on x86-64=E2=80=94on aarch64, you will have to de= al with the outline atomics most distributions use. I suggest you base your OpenJDK work on the OpenJDK musl port. This way, you can carefully control what you build and how you build it, and also make it impossible to pick up system libraries by accident. And static JNI would be a good fit if you do not expect JNI to be used anyway. Thanks, Florian