From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <SRS0=oekO=7T=deneb.enyo.de=fw@sourceware.org>
Received: from albireo.enyo.de (albireo.enyo.de [37.24.231.21])
	by sourceware.org (Postfix) with ESMTPS id C7E113858D37
	for <libc-alpha@sourceware.org>; Mon, 27 Mar 2023 00:33:07 +0000 (GMT)
DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org C7E113858D37
Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=deneb.enyo.de
Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=deneb.enyo.de
Received: from [172.17.203.2] (port=55113 helo=deneb.enyo.de)
	by albireo.enyo.de ([172.17.140.2]) with esmtps (TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256)
	id 1pganJ-00FMhv-IB; Mon, 27 Mar 2023 00:33:05 +0000
Received: from fw by deneb.enyo.de with local (Exim 4.96)
	(envelope-from <fw@deneb.enyo.de>)
	id 1pganJ-001xhg-1P;
	Mon, 27 Mar 2023 02:33:05 +0200
From: Florian Weimer <fw@deneb.enyo.de>
To: John David Anglin <dave@parisc-linux.org>
Cc: libc-alpha@sourceware.org,  deller@gmx.de
Subject: Re: [committed] hppa: Drop 16-byte pthread lock alignment
References: <ZCC3g2nKEtpz36nR@mx3210.localdomain>
Date: Mon, 27 Mar 2023 02:33:05 +0200
In-Reply-To: <ZCC3g2nKEtpz36nR@mx3210.localdomain> (John David Anglin's
	message of "Sun, 26 Mar 2023 21:22:11 +0000")
Message-ID: <87sfdrvxry.fsf@mid.deneb.enyo.de>
MIME-Version: 1.0
Content-Type: text/plain
X-Spam-Status: No, score=-5.8 required=5.0 tests=BAYES_00,KAM_DMARC_STATUS,SPF_HELO_NONE,SPF_PASS,TXREP autolearn=ham autolearn_force=no version=3.4.6
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org
List-Id: <libc-alpha.sourceware.org>

* 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.