From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pj1-x102c.google.com (mail-pj1-x102c.google.com [IPv6:2607:f8b0:4864:20::102c]) by sourceware.org (Postfix) with ESMTPS id 345B23858D34 for ; Mon, 20 Apr 2020 00:29:15 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 345B23858D34 Received: by mail-pj1-x102c.google.com with SMTP id np9so3784740pjb.4 for ; Sun, 19 Apr 2020 17:29:15 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:subject:to:cc:references:in-reply-to :mime-version:message-id:content-transfer-encoding; bh=imCIcolOR7B1A4TEDHO6HBkSJsW1cQgUD3JjwK/tiPg=; b=WxCcps7mRjAMbCGZC9A5Ymlx5A8GEfcLaSfzKJV8gH810+zBHPhi/ucqHK5szx5NWK UfJQ4WZmiasnpfgHOXpHW7xdznuH6CyeF7lhIPpN/YwK0KiivyWT+hOkL4A3PhG1YUhk 5v28qAcYA3xFYStxHbns63Ivz1Yyhpu2LDgZVQF1ZQyvrnvTrZYZjFlljVT2WzCn9IqS PR+ZQ2YKT/J1wLmG5d0r/drpU8SzGwnv14QIbPcisssI3xMUGeTx4r4C9W2z0g/vG33E qOjkJfRUKesmkARk9HTa+GCHW1wRHeduOj0iYXm8fIZidYTVRkKd1g6oZ/Jmm1WOpFwD 5c6w== X-Gm-Message-State: AGi0PuZ9aUVOdoPjBxsKS9lu6f0UssBISJ4NhPSAD6WHqqBxQCQ65f5B 9s/3UKNrtcLgEfsHXrhVmY5fV5EzEn4= X-Google-Smtp-Source: APiQypJ1Dfo/ScPKElMBVsp9hDMItwSA9AWQX4RGON7Z3pxE56GCUuB8+mvbqjlGodVKxXO4eQlAHw== X-Received: by 2002:a17:90a:23ad:: with SMTP id g42mr17605654pje.35.1587342553985; Sun, 19 Apr 2020 17:29:13 -0700 (PDT) Received: from localhost ([203.185.249.170]) by smtp.gmail.com with ESMTPSA id t12sm19938251pgm.37.2020.04.19.17.29.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 19 Apr 2020 17:29:13 -0700 (PDT) Date: Mon, 20 Apr 2020 10:27:58 +1000 From: Nicholas Piggin Subject: Re: [musl] Powerpc Linux 'scv' system call ABI proposal take 2 To: Nicholas Piggin via Libc-alpha , Szabolcs Nagy Cc: Rich Felker , libc-dev@lists.llvm.org, linuxppc-dev@lists.ozlabs.org, musl@lists.openwall.com References: <1586931450.ub4c8cq8dj.astroid@bobo.none> <20200415225539.GL11469@brightrain.aerifal.cx> <1586994952.nnxigedbu2.astroid@bobo.none> <20200416095800.GC23945@port70.net> In-Reply-To: <20200416095800.GC23945@port70.net> MIME-Version: 1.0 Message-Id: <1587341904.1r83vbudyf.astroid@bobo.none> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Spam-Status: No, score=-1.5 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, FREEMAIL_FROM, KAM_NUMSUBJECT, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=no 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: Mon, 20 Apr 2020 00:29:16 -0000 Excerpts from Szabolcs Nagy's message of April 16, 2020 7:58 pm: > * Nicholas Piggin via Libc-alpha [2020-04-16 = 10:16:54 +1000]: >> Well it would have to test HWCAP and patch in or branch to two=20 >> completely different sequences including register save/restores yes. >> You could have the same asm and matching clobbers to put the sequence >> inline and then you could patch the one sc/scv instruction I suppose. >=20 > how would that 'patch' work? >=20 > there are many reasons why you don't > want libc to write its .text I guess I don't know what I'm talking about when it comes to libraries.=20 Shame if there is no good way to load-time patch libc. It's orthogonal to the scv selection though -- if you don't patch you have to=20 conditional or indirect branch however you implement it. Thanks, Nick