From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MIME_QP_LONG_LINE, SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D364FC433E2 for ; Tue, 30 Mar 2021 17:09:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9F5366196C for ; Tue, 30 Mar 2021 17:09:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232246AbhC3RHK (ORCPT ); Tue, 30 Mar 2021 13:07:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51724 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232458AbhC3RGb (ORCPT ); Tue, 30 Mar 2021 13:06:31 -0400 Received: from mail-pj1-x1030.google.com (mail-pj1-x1030.google.com [IPv6:2607:f8b0:4864:20::1030]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2390CC061574 for ; Tue, 30 Mar 2021 10:06:02 -0700 (PDT) Received: by mail-pj1-x1030.google.com with SMTP id j6-20020a17090adc86b02900cbfe6f2c96so7996183pjv.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=ZkVoV7Cs0roc6Ef/K7cLhKDldfXKS8tJ28SqwqykG6A9FXPNltaPXwMdPMx5BZfGwW pY18Toj+RUHgdUL6WfZ49KZpRUmWixtNp2Ysocs02z6LkDR8Auvt6V6NkoZAdJh541Y2 mmYKZZznV/6kI4XDOvZMZNdLJrykLReguLWHRGU/AGbnMmF+t61f5U3ohbmbMB6KzTSU 8Zx0N1BOl8q+t95HYQ2LLmQbHqsFAg9QKB44Nt+G5ycWWUTRop+jLSr0tYcEzYeudMpC hAbwgC4kyC+O9m3y/25v3m4pZk5nWoipuFVKm5fYy4ZOcnk5cKxqRxzFMSY7R4GYiCqR PXaw== X-Gm-Message-State: AOAM531RUK0hNFnDpOkSzySLE5OjUsq2R25rA3HwhpElDfFbR6P7x9y3 l6vSJFZwaCysaBxl8MA1jJ2gXQ== 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) Precedence: bulk List-ID: X-Mailing-List: linux-api@vger.kernel.org > 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.=