From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp.gentoo.org (dev.gentoo.org [IPv6:2001:470:ea4a:1:5054:ff:fec7:86e4]) by sourceware.org (Postfix) with ESMTP id 58A0A3858D37 for ; Mon, 27 Mar 2023 00:38:38 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 58A0A3858D37 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=gentoo.org Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=gentoo.org References: <87sfdrvxry.fsf@mid.deneb.enyo.de> User-agent: mu4e 1.8.14; emacs 29.0.60 From: Sam James To: Florian Weimer Cc: John David Anglin , deller@gmx.de, libc-alpha@sourceware.org Subject: Re: [committed] hppa: Drop 16-byte pthread lock alignment Date: Mon, 27 Mar 2023 01:37:28 +0100 In-reply-to: <87sfdrvxry.fsf@mid.deneb.enyo.de> Message-ID: <87zg7zc9km.fsf@gentoo.org> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha512; protocol="application/pgp-signature" X-Spam-Status: No, score=-4.1 required=5.0 tests=BAYES_00,JMQ_SPF_NEUTRAL,KAM_DMARC_STATUS,SPF_HELO_PASS,SPF_PASS,TXREP autolearn=no autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: --=-=-= Content-Type: text/plain Florian Weimer writes: > * John David Anglin: > >> hppa: Drop 16-byte pthread lock alignment >> >> Linux threads were removed about 12 years ago and the current >> nptl implementation only requires 4-byte alignment for pthread >> locks. >> >> The 16-byte alignment causes various issues. For example in >> building ignition-msgs, we have: >> >> /usr/include/google/protobuf/map.h:124:37: error: static assertion failed >> 124 | static_assert(alignof(value_type) <= 8, ""); >> | ~~~~~~~~~~~~~~~~~~~~^~~~ >> >> This is caused by the 16-byte pthread lock alignment. > > This was done deliberately to preserve ABI. This change needs a mass > rebuild because struct offsets after pthread_mutex_t members are > likely to change. On HPPA, I think we _may_ be fine with ABI breaks, but of course we should use the proper mechanisms for that if we're doing it to advertise it fully and allow distributions and users to prepare. (We've done them before and there's not really any cache of binaries that we need to keep compat. with anyway, it's more important to keep things building usually.) thanks, sam --=-=-= Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iOUEARYKAI0WIQQlpruI3Zt2TGtVQcJzhAn1IN+RkAUCZCDlil8UgAAAAAAuAChp c3N1ZXItZnByQG5vdGF0aW9ucy5vcGVucGdwLmZpZnRoaG9yc2VtYW4ubmV0MjVB NkJCODhERDlCNzY0QzZCNTU0MUMyNzM4NDA5RjUyMERGOTE5MA8cc2FtQGdlbnRv by5vcmcACgkQc4QJ9SDfkZDJfQD6A0edKsbmtta2tb5oderP3kwdwZHjGZPaIKy5 KY/MgskA/RP64R9o4bP4qMwm+F8XTo2LztGqBGlKlOf0oZC8SVAF =jchk -----END PGP SIGNATURE----- --=-=-=--