From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pj1-x1032.google.com (mail-pj1-x1032.google.com [IPv6:2607:f8b0:4864:20::1032]) by sourceware.org (Postfix) with ESMTPS id 853953858002 for ; Tue, 30 Mar 2021 17:06:02 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 853953858002 Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=amacapital.net Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=luto@amacapital.net Received: by mail-pj1-x1032.google.com with SMTP id cl21-20020a17090af695b02900c61ac0f0e9so1597688pjb.1 for ; Tue, 30 Mar 2021 10:06:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amacapital-net.20150623.gappssmtp.com; s=20150623; h=content-transfer-encoding:from:mime-version:subject:date:message-id :references:cc:in-reply-to:to; bh=U4q+4X4ovNbgyNm+vnYZ55+5sJJ03R3eRaFFwvvHanQ=; b=1erBt5yBguM3wu5x53SxPYcY+u0nb/gz/8dRWvk3RKVyKuuKPlloDIcIiBqKotYZCY sStJJ0lBlWkWwVaDrw7WHNHg9t9R1rrEpYhSrYYLuP1epKnSWoYHANJEVMSTUXAi2wML yk1+3mCKwARJa5NcHHC/g+J63eIL3aR818xSS4VpQ4czEfXr8kULsosM4jm4MIIdgnfM FNyeqmJbKVErhig2aRM3bWdc8MIZAJ2JYM5W9NqgWVT//REhUi1GXwDwUZ9LqpyDkpZv TIA0GrjSvfVfmmUh2Smsa1Ts1w2JiCvr8DMR6GURTunEuQZzak6C0WZOM9ZEBeK0dTkg hKuw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:content-transfer-encoding:from:mime-version :subject:date:message-id:references:cc:in-reply-to:to; bh=U4q+4X4ovNbgyNm+vnYZ55+5sJJ03R3eRaFFwvvHanQ=; b=BcAJV/bmUVDU8ACd/krZTBw+/xtNIYCBOug+IXv/HphP4FvNl2x+9Ph9qx2DGUBenE g/l5iKz4jcCvgNZTsY7FxuZF0nkaAMyI1KesN2ZnzLdHdy7njwiq0MsYxPaUjqs9JkMk YXOpZudjq4uS30bKAIEZ6y3zpmfraZ1xM+enuCFSs93MAG3IaEwMiBUsl41OIsgDqblJ kF3yZ+wGPkyd4pkcR98pXc526yYlZKaquBULG6QmhG58Ph2xkVfu0pfkCegRhlX5Hb8I zsKLWErXNdLijgYmhKluDT2qZ2oTWCGTsfLo+SvZKqOIWrVnU0z3HHV5FkeorMEicydC WR3w== X-Gm-Message-State: AOAM53092Iriwe8+wAuisVgv/2PjZi7KavsBTKQb06miBK/+TgJdowwA dDcfB7y5ZFelW1sd2szZoWpX8A== X-Google-Smtp-Source: ABdhPJwiNtg82+2n7Ww23Sbgvk1m2HyIMfb69Sf2f7CaQTCRDT8JKO/LDuIn1LbMKoFYmV/hJdJ0pQ== X-Received: by 2002:a17:90a:68cf:: with SMTP id q15mr5261816pjj.231.1617123961665; Tue, 30 Mar 2021 10:06:01 -0700 (PDT) Received: from ?IPv6:2601:646:c200:1ef2:547a:17da:91e6:2591? ([2601:646:c200:1ef2:547a:17da:91e6:2591]) by smtp.gmail.com with ESMTPSA id a26sm16241008pff.149.2021.03.30.10.06.00 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 30 Mar 2021 10:06:01 -0700 (PDT) Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable From: Andy Lutomirski Mime-Version: 1.0 (1.0) Subject: Re: Candidate Linux ABI for Intel AMX and hypothetical new related features Date: Tue, 30 Mar 2021 10:05:59 -0700 Message-Id: References: Cc: Andy Lutomirski , Greg KH , "Bae, Chang Seok" , Dave Hansen , X86 ML , LKML , libc-alpha , Florian Weimer , Rich Felker , Kyle Huey , Keno Fischer , Linux API In-Reply-To: To: Len Brown X-Mailer: iPhone Mail (18D70) X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, MIME_QP_LONG_LINE, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 30 Mar 2021 17:06:04 -0000 > On Mar 30, 2021, at 10:01 AM, Len Brown wrote: >=20 > =EF=BB=BFAndy, >=20 > I agree, completely, with your description of the challenge, > thank you for focusing the discussion on that problem statement. >=20 > Question: >=20 > Is it required (by the "ABI") that a user program has everything > on the stack for user-space XSAVE/XRESTOR to get back > to the state of the program just before receiving the signal? The current Linux signal frame format has XSTATE in uncompacted format, so e= verything has to be there. Maybe we could have an opt in new signal frame fo= rmat, but the details would need to be worked out. It is certainly the case that a signal should be able to be delivered, run =E2= =80=9Casync-signal-safe=E2=80=9D code, and return, without corrupting regist= er contents.=