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_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 32356 invoked from network); 31 May 2020 01:55:47 -0000 Received: from mother.openwall.net (195.42.179.200) by inbox.vuxu.org with ESMTPUTF8; 31 May 2020 01:55:47 -0000 Received: (qmail 9720 invoked by uid 550); 31 May 2020 01:55:45 -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 15509 invoked from network); 31 May 2020 00:57:34 -0000 Date: Sun, 31 May 2020 00:57:12 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=protonmail.com; s=protonmail; t=1590886642; bh=ODFUmKTqUnFad/cRgNMMBXAJHE0Nr41/obQ0vWTk2po=; h=Date:To:From:Cc:Reply-To:Subject:In-Reply-To:References:From; b=kVzWAndbkai0W/Iwm24Wy6tSzPskRqq+PYAH/xBGoqneGv+B48k6dT2oNwKRNqLcV srk0BcqwH6jrGQuEDt6LNUNQQJyP3hGlilAtTAUiVxIkRwqF61tVODr0INlFMyIkjr sqGNeHGYP0ECy6m2snfnZxelBW34AewquAVQXJHA= To: Segher Boessenkool , linuxppc-dev@lists.ozlabs.org From: Will Springer Cc: libc-alpha@sourceware.org, eery@paperfox.es, daniel@octaforge.org, musl@lists.openwall.com, binutils@sourceware.org, libc-dev@lists.llvm.org Message-ID: <2956705.fEcJ0Lxnt5@sheen> In-Reply-To: <20200530192212.GG31009@gate.crashing.org> References: <2047231.C4sosBPzcN@sheen> <20200530192212.GG31009@gate.crashing.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Subject: [musl] Re: ppc64le and 32-bit LE userland compatibility On Saturday, May 30, 2020 12:22:12 PM PDT Segher Boessenkool wrote: > The original sysv PowerPC supplement > http://refspecs.linux-foundation.org/elf/elfspec_ppc.pdf > supports LE as well, and most powerpcle ports use that. But, the > big-endian Linux ABI differs in quite a few places, and it of course > makes a lot better sense if powerpcle-linux follows that. Right, I should have clarified I was talking about Linux ABIs=20 specifically. > What patches did you need? I regularly build >30 cross compilers (on > both BE and LE hosts; I haven't used 32-bit hosts for a long time, but > in the past those worked fine as well). I also cross-built > powerpcle-linux-gcc quite a few times (from powerpc64le, from powerpc64, > from various x86). There was just an assumption that LE =3D=3D powerpc64le in libgo, spotted b= y=20 q66 (daniel@ on the CC). I just pushed the patch to [1]. > Almost no project that used 32-bit PowerPC in LE mode has sent patches > to the upstreams. Right, but I have heard concerns from at least one person familiar with=20 the ppc kernel about breaking existing users of this arch-endianness=20 combo, if any. It seems likely that none of those use upstream, though ^^; > The ABI says long longs are passed in the same order in registers as it > would be in memory; so the high part and the low part are swapped > between BE and LE. Which registers make up a pair is exactly the same > between the two. (You can verify this with an existing powerpcle-* > compiler, too; I did, and we implement it correctly as far as I can > see). I'll give it a closer look. This is my first time poking at this sort of=20 thing in depth, so excuse my unfamiliarity! > A huge factor in having good GCC support for powerpcle-linux (or > anything else) is someone needs to regularly test it, and share test > results with us (via gcc-testresults@). Hint hint hint :-) >=20 > That way we know it is in good shape, know when we are regressing it, > know there is interest in it. Once I have more of a bootstrapped userland than a barely-functional=20 cross chroot, I'll get back to you on that :) =20 > gl;hf, >=20 >=20 > Segher Thanks, Will [she/her] [1]: https://github.com/Skirmisher/void-packages/blob/master/srcpkgs/gcc/pa= tches/libgo-ppcle.patch