From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-3.1 required=5.0 tests=DKIM_ADSP_CUSTOM_MED, DKIM_INVALID,DKIM_SIGNED,FREEMAIL_FROM,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED,RCVD_IN_MSPIKE_H3,RCVD_IN_MSPIKE_WL autolearn=ham autolearn_force=no version=3.4.4 Received: (qmail 4037 invoked from network); 20 May 2021 02:46:17 -0000 Received: from mother.openwall.net (195.42.179.200) by inbox.vuxu.org with ESMTPUTF8; 20 May 2021 02:46:17 -0000 Received: (qmail 11654 invoked by uid 550); 20 May 2021 02:46:15 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Reply-To: musl@lists.openwall.com Received: (qmail 11613 invoked from network); 20 May 2021 02:46:14 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:subject:to:cc:references:in-reply-to:mime-version :message-id:content-transfer-encoding; bh=8M1OxdiUM2X6HRQVrD30T5IbKemIPC0lXDlSqpSaszE=; b=RBRzO79+q6UeCkV6IpxJraBj4XsWeQB+5AYG6+p65y3z77c6RpLcQylNbCDGFIHVv7 Ae1gcNnPs4mfAWINBeWY86Rc0HF+Bp1/UdafRrPGmOIc4kSaZlwgiigXoqRoTdkkif9t gvMHZV64lDeY7rFSOgF752N2bZHVKJDdzjcvJglfmeejKJY1g+lFS32sufup4VL5ZgXy BM5lwphhnr6nC3TZ+PlWUQPuFzF6E/ZnfDqZzFJQI6CPvMWwilX/ll2Orb9hjj1dVy/n MFdYLsDJIDTjR7kBwB/FZSaCHw/TMeRLUk235GZCEspc3tm6qGvLbpTlafr3jPM7lVe+ CzyA== 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=8M1OxdiUM2X6HRQVrD30T5IbKemIPC0lXDlSqpSaszE=; b=XDJ9SXOY5fuf5qg6Hlj+pHYsCeKNMRQlZWZVJLgLgwlw8a/7xD3CbXNZLxzgYMtU62 e8J0E5Yiu3+jjEdszGbLrXkTcWoEkvPV/wed2zipoKvnSBLy8+CbkZHf7jOi+SUKCRcf qfhEXsBDSsDmeb+667P4OiUTFuUFZRBn+uNwCVpg7udTK1MZDmzfW1zna82KnjWWw2Ks HoX01dI1X1oVTThAy8+VVQd6j5JxAgypY4QpOJQzFE5VWuPPkOGYfZfXgI6THUUj5FLL K9YhtGDbgns6B4urAE+H7y/uiWxpkQHPwyj3Fr+GsSC/Ub/N1spGKDMxXwjrq6qHrGbC I3/g== X-Gm-Message-State: AOAM533Q6XAVCqyV+10Jboc5EtyJERPIUzIty9yTVBdgdFAjP4Z3GYiD boSPzNu84WPr1gJABC4vUkc= X-Google-Smtp-Source: ABdhPJxPRLYd9U7WwUvIqQ1f2wFxuqNJ9T/QrAgVoan54fa7ROHdL889+khZG/PVxHA1U+QPzuVNXg== X-Received: by 2002:a05:6a00:26d4:b029:2df:87f2:fcc4 with SMTP id p20-20020a056a0026d4b02902df87f2fcc4mr2233646pfw.20.1621478762558; Wed, 19 May 2021 19:46:02 -0700 (PDT) Date: Thu, 20 May 2021 12:45:57 +1000 From: Nicholas Piggin To: Rich Felker , "Dmitry V. Levin" Cc: Joakim Tjernlund , linux-api@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, Michael Ellerman , musl@lists.openwall.com, Segher Boessenkool References: <20210518231331.GA8464@altlinux.org> <9b5ea7059c5a5d4e9ccccd7d73ce2c66b2203f52.camel@infinera.com> <1621410291.c7si38sa9q.astroid@bobo.none> <1621413143.oec64jaci5.astroid@bobo.none> <20210519143836.GJ10366@gate.crashing.org> <11d62aa2488e51ec00fe77f24a1d7cdcc21af0b8.camel@infinera.com> <20210519152205.GL10366@gate.crashing.org> <20210519234846.GS2546@brightrain.aerifal.cx> <20210520010612.GA25599@altlinux.org> In-Reply-To: <20210520010612.GA25599@altlinux.org> MIME-Version: 1.0 Message-Id: <1621478448.743zqcrxza.astroid@bobo.none> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Subject: [musl] Re: Linux powerpc new system call instruction and ABI Excerpts from Dmitry V. Levin's message of May 20, 2021 11:06 am: > On Wed, May 19, 2021 at 07:48:47PM -0400, Rich Felker wrote: >> On Wed, May 19, 2021 at 06:09:25PM +0000, Joakim Tjernlund wrote: > [...] >> > W.r.t breaking ABI, isn't that what PowerPC is trying to do with the n= ew syscall I/F?=20 >>=20 >> No, it's a new independent interface. >=20 > Unfortunately, being a new independent interface doesn't mean it isn't > an ABI break. In fact, it was a severe ABI break, and this thread is > an attempt to find a hotfix. It is an ABI break, that was known. The ptrace info stuff I fixed with=20 the patch earlier was obviously a bug in my initial implementation and=20 not intended (sorry my ptrace testing was not sufficient, and thanks for reporting it, by the way). But the register ABI was always a known break. The issue is that rfscv clobbers LR, so it can not support the old ABI. If the old ABI did not=20 preserve LR, then we may have chosen to not change register ABI at all. Thanks, Nick