From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 67392 invoked by alias); 15 Apr 2016 16:10:00 -0000 Mailing-List: contact binutils-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: binutils-owner@sourceware.org Received: (qmail 67374 invoked by uid 89); 15 Apr 2016 16:09:59 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.2 required=5.0 tests=AWL,BAYES_00,SPF_PASS autolearn=ham version=3.3.2 spammy=HX-Exchange-Antispam-Report-CFA-Test:9101521026, gen, preempted, H*Ad:U*ccoutant X-HELO: eu-smtp-delivery-143.mimecast.com Received: from eu-smtp-delivery-143.mimecast.com (HELO eu-smtp-delivery-143.mimecast.com) (207.82.80.143) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Fri, 15 Apr 2016 16:09:40 +0000 Received: from emea01-am1-obe.outbound.protection.outlook.com (mail-am1lrp0011.outbound.protection.outlook.com [213.199.154.11]) (Using TLS) by eu-smtp-1.mimecast.com with ESMTP id uk-mta-26-k5xjdFHCSNKG3H3iRKiy2w-1; Fri, 15 Apr 2016 17:09:35 +0100 Received: from [10.2.206.73] (217.140.96.140) by DB5PR08MB1093.eurprd08.prod.outlook.com (10.166.174.16) with Microsoft SMTP Server (TLS) id 15.1.453.26; Fri, 15 Apr 2016 16:09:32 +0000 Message-ID: <57111238.3060800@arm.com> Date: Fri, 15 Apr 2016 16:10:00 -0000 From: Szabolcs Nagy User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.8.0 MIME-Version: 1.0 To: Ramana Radhakrishnan , Jeff Law CC: Cary Coutant , "H.J. Lu" , Joe Groff , Alan Modra , Binutils , Subject: Re: Preventing preemption of 'protected' symbols in GNU ld 2.26 References: <983472E1-A1BC-4970-9CF9-0138A6BAD16D@apple.com> <6AAD87D2-90F9-4AD7-A195-AC91B76EA6AE@apple.com> <56FB5061.9010303@redhat.com> <56FC74E7.1000700@redhat.com> In-Reply-To: X-ClientProxiedBy: VI1PR06CA0039.eurprd06.prod.outlook.com (10.162.116.177) To DB5PR08MB1093.eurprd08.prod.outlook.com (10.166.174.16) X-MS-Office365-Filtering-Correlation-Id: b4a6a0ce-a1b8-49fc-de83-08d365485594 X-Microsoft-Exchange-Diagnostics: 1;DB5PR08MB1093;2:/YGBtCXfXqBG8JmZl3NCbBOeluIN7nfeUUxgIE+APiVU1uqlucV4b+i3dDUAYewbVTBmaXPAESMj7P5wEQBoPLQMvxM70U8G4VdIexOqibmSsrCPJqNwI4I5Lwn1d4/lQVAstUTstjKaqK838rCmJPLfzwQohTnW1L6JdzuNrA0wRKSXwnaMm5GDRVgSxWqh;3:JqTrsJWsf/Ff/beE6yJuDIbTXf6oXN7Lvk946TR6Jp8hsTXSaHEhEFMFINoZO67Q13oiriKE48Kdl2G4hqfNXtJd9qnnBC1+SCVb6qjqtQ6hmalBEqY9cAGvbo3i1/Q+;25:snUCdDwRAQUN2tSLgKqSihFLcz3JWDS1Kwkh6RR4M/d//0NKfw/coZWtZHMgYa/TfydJqW2EetX4o4wT6KiCAxY/tsYvpUVFoTxni1nmBlsw6vdfQp9PUlpEZHBki1TN54aXx8YuHnqeDjrpYzMjwYw1CFLU3p6gcKXSvvW1V18QY6nKL+F0byihIFwqaieQrMEz7tcGoWdkdlGEHhIB0stu4gUHugaYLTWXb8h+lkVj/iuk/q53hQpcahpXLv+rHygVDpLZ+uE1s4vBAJ5JlAPGhHBOo6ELL14YewHlChW/DCSM1sqNfkiyljmsBsl2xNmCQ7OrDhKHOlD0VfTkNQ==;20:oBvu0ptiVQ/egBdrt4YIxh2zqsxgSf77grDhIWiMX6YlqjacP3TkLa3XnZl7YrT3DUoDSSBicC/9NJolp2l+twYhQcBEz4fpL3vUT0c2BJsUuRGmw9fQI0Y+pJTCIcI35Cx34zrAgDZrQtyQ1cfnFUXnYenGDLGI/DEmsloq+uo= X-Microsoft-Antispam: UriScan:;BCL:0;PCL:0;RULEID:;SRVR:DB5PR08MB1093; NoDisclaimer: True X-Microsoft-Antispam-PRVS: X-Exchange-Antispam-Report-Test: UriScan:; X-Exchange-Antispam-Report-CFA-Test: BCL:0;PCL:0;RULEID:(9101521026)(601004)(2401047)(8121501046)(5005006)(3002001)(10201501046)(6055026);SRVR:DB5PR08MB1093;BCL:0;PCL:0;RULEID:;SRVR:DB5PR08MB1093; X-Microsoft-Exchange-Diagnostics: 1;DB5PR08MB1093;4:JGDtp1y272A3eiDpeBVRA2tUBGkKGo/VAT9hn3QLd3jBg8s/+lmzSzhaSDlLqHHmKe38Pboy7pf8VZSYt8js5fitJ+SXSwVT6iG6Wc7Br8Ixx84xArsDoR8qRlN1mp6gi3Ik8b5BvsO2Z1uUgIG3Su4rJ7vdN8XfPlHBvhGVs5dx5v4dw0NQCVR85Igg8TtDoUVoXyknfij5SKUcDf6UXyQFNYUhLLuImtrHXNnkRr04/OGsBDdovAGohDcf0BzQ+hJDxjl/yvKuzRdK6RSQj8BM6mM46uKsYWYJc8qc6l9q9gEyvZlq+XMZfMXLKCk/pdGWQDm9OZgGiL9H2i1Zvc4SdkW3kTZ+cMR5xg9shSGucaiHFokWNZZqS6J93GZOQ4qQLalRA1P8UtAKxTBO2VrUYQMlnJvnTVQuLm28PfQ= X-Forefront-PRVS: 0913EA1D60 X-Forefront-Antispam-Report: SFV:NSPM;SFS:(10009020)(4630300001)(6009001)(377454003)(24454002)(93886004)(4001350100001)(77096005)(5001770100001)(87266999)(54356999)(5008740100001)(76176999)(50986999)(65806001)(65956001)(230700001)(117636001)(66066001)(36756003)(47776003)(92566002)(59896002)(64126003)(19580405001)(86362001)(19580395003)(164054004)(42186005)(50466002)(1096002)(122286003)(99136001)(4326007)(23676002)(5004730100002)(81166005)(586003)(83506001)(2950100001)(6116002)(189998001)(3846002)(15975445007)(2906002)(7059030)(62816006);DIR:OUT;SFP:1101;SCL:1;SRVR:DB5PR08MB1093;H:[10.2.206.73];FPR:;SPF:None;MLV:sfv;LANG:en; X-Microsoft-Exchange-Diagnostics: =?utf-8?B?MTtEQjVQUjA4TUIxMDkzOzIzOkZSSy9Va3phYzdoZzVhbGhjRkxFNnkwK1RN?= =?utf-8?B?eWJSWlJxMmRGU05mOXdJRjRFTFArdS95VHhZbHZTL0RlWFFFUHlCY3prZmdZ?= =?utf-8?B?VTY0R3VRcjJDZFVYQVpuUDR5RThTMnN6bmhCTGdWaTErdUFMZGpjUDhxVFZv?= =?utf-8?B?cDBuUkpzMTZyejIvMFhBZ1VDa2YvTzJ0Z1B0QnAwRmQ4YTRKYVpPVm43T2kv?= =?utf-8?B?WDgzaEsrZXFtZTVqK3ZTdTNCVWRHM2xIV0w4TzN5Y0xxdzhEUVN3UnI1ejFQ?= =?utf-8?B?aCtrV1hPYkY4MURhRUIwYWFRbHlNMjNzenJUSmt5emdJV21NM1BxRVFwVDVh?= =?utf-8?B?RWhMNzNaQ254MytjbElKWDBKWGhEZUp5ZkFsTGNKSVM5UHZ5dmVHT2c5MTht?= =?utf-8?B?cFRvL3RkenMvVlBkSmVONlYrdWkxazRTS2doY280d0kzdkxzMnFYbzM5NlJO?= =?utf-8?B?R0loZXZJTHpucnFBNDNsTXFJRVV1dWVKUjhRa25xeFlpQnIvSk9BcHdCT3N0?= =?utf-8?B?RlYrYXZBWENIQTZDcElFN0pnNDVCd2xkRGRsNlV3TU02NkpHWEl1M1R2Ykdk?= =?utf-8?B?c3dGd3RSTFVJUy9MTWk2Z29YcXdwK2lQMU04d2ExK3JFem50SWEwTFhKL1k5?= =?utf-8?B?WXJRdmFoTzBNOG5uUlNzU3Z5L1U0WEUxdmw0SmNoYXRqNlFqUTEyVnkzRE1w?= =?utf-8?B?Z3lvV2JYNUxTTUJZQkQwLzdTcWVIMWFEUUV1RnM2MVRKUHhCTFo3K0pDb3lu?= =?utf-8?B?MG1NajJEcVZyNVRSL2Y1YURaYkFDbnVSZG9Zd3hRR1M1RnFiK0xFMmFibzE1?= =?utf-8?B?bGYvOFBEd2MybnhKQVpxWitPTTlJb1dLSnkwQ1ViZWprKzBnbUo3eU92K0Vj?= =?utf-8?B?K2h2UGh6bVB2d212Y2MxTnhjUGtyZElzQ3p0N01UREh2cHhVZE4xNjAzdjlD?= =?utf-8?B?Wk9heXpwMU8ydkVFamxVT2ZpdkpzbmpRSlhvUzQ1N3RmZXhWUStuZllFWEZj?= =?utf-8?B?cVI5N2tqby96NlZpYjZWWmpGS2dKblkrNVpOMXUwaWhNNnJrSUZwMlBDRmg5?= =?utf-8?B?ZElGNmJ2dG0rajVwRnZ0QnZKcVpiQ0RWeXZOaDFRWE9McklFTC9JSVZPQlFC?= =?utf-8?B?WmVaRmdEMUlzQUQ0RXFwTVFiTjg0WXVzWHpXUnJXcW93QU9BWllXeFlLUmkr?= =?utf-8?B?cTZlK1BXV1N1MWE1RHJBbEIwbE5BMlhrQ0NPeGF5MmxpOTlXejFCLzRNRXJQ?= =?utf-8?B?N3p2SzQ1Y0swOCtxZ0pQK0ZyVXdaeEFGY29HeHpBSGFzblI4VTBVemIrRW81?= =?utf-8?B?aC8rbXROckdxUDBDcmJjdHozdzdvWEhIdEN1eXBWcnRYRnhyMEowVDlkTDhG?= =?utf-8?B?QWorOGVUTzdMSEZ1TGM4MlBXVzlMZ2FkTHByY241RGRyZ2o5WWxjZ1MxakZR?= =?utf-8?B?QjZ6SWhHQUZsVkZwajF2YnhodHh1eG5sRDEvdThQd1BLVERHTC9CN2plbUEy?= =?utf-8?B?eENrSlBsNU1iY0VDM0FFMTFpTkx2ZlRMQUlaR0VxUlViQjJJblB4eWRqbkJJ?= =?utf-8?B?eVIwM1BncW9qZHlMZUE2VmRISFFkR2xseTFTaHZRQTAxZ0tQOWRRZHhnL2Zo?= =?utf-8?Q?gKPF7kO8YZXdQTbHJH93?= X-Microsoft-Exchange-Diagnostics: 1;DB5PR08MB1093;5:DmmD0QkmaBP7UltGvmmCEFOzS2BTgKnaF8uDY0tAnb3/BtTGmgIWnQqWb4u5pwmZ5ffb0c4L7NuEn2Hjj1/E5FHijhmMHgcV5lFgJyG7aZiC9A2gHj2jG6KM/rMFf/TkU1AVC5Q3B5ddV1bUMrS4rQ==;24:nQTvgTZuIku9REyRevJpl5+0xOPRf+jEWXbsp0fgx1Rj9177YvpkWZPYFr7+dbxYLzkR9qQf7/gbbejuVP0dOiYD8Iaz9h/GsfYuDs9nE68=;20:8qUuDo1/P1evl9pQUrHL51Y9AvgNC4bFO2NPzjWS31Rdo7thULaoRJEEbR0KxHXMPlKBIwep7xqOOV4DO2BHmC/ZPoDHi6aSQQrSVSeW8CqAx8YAEmz6P3yDSbG1FxuuGV6OxiEYpZ8dE6HcjBE2RmeLt3RNm6N3nVNAHcmgrF4= SpamDiagnosticOutput: 1:23 SpamDiagnosticMetadata: NSPM X-OriginatorOrg: arm.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 15 Apr 2016 16:09:32.9429 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-Transport-CrossTenantHeadersStamped: DB5PR08MB1093 X-MC-Unique: k5xjdFHCSNKG3H3iRKiy2w-1 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-IsSubscribed: yes X-SW-Source: 2016-04/txt/msg00234.txt.bz2 On 31/03/16 14:26, Ramana Radhakrishnan wrote: > On Thu, Mar 31, 2016 at 1:52 AM, Jeff Law wrote: >> On 03/30/2016 06:40 PM, Cary Coutant wrote: >>>> >>>> It would help me immensely on the GCC side if things if you and Alan >>>> could >>>> easily summarize correct behavior and the impact if we were to just >>>> revert >>>> HJ's change. A testcase would be amazingly helpful too. >>> >>> >>> It looks like it's not just the one change. There's this patch: >>> >>> https://gcc.gnu.org/ml/gcc-patches/2015-07/msg01871.html >>> >>> which took the idea that protected can still be pre-empted by a COPY >>> relocation and extended it to three more targets that use COPY >>> relocations. >>> >>> I wonder how many other patches have been based on the same >>> misunderstanding? (sorry i missed this thread) this was not a misunderstanding. that patch is necessary for correctness (odr) in the presence of copy relocations as described in https://gcc.gnu.org/ml/gcc-patches/2015-09/msg02365.html and https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D55012 this was a long standing code gen bug in gcc and was about time to fix it (it was also broken in glibc's dynamic linker, but e.g. not in musl libc). (i don't see what is the issue with using the copy in the main executable from a shared library, performance is not a correctness issue, nor how it is possible to avoid the copy relocs.) >> >> I don't think it was many -- I certainly recall the arm/aarch64 variant. >> There may have been one other varasm.c change in this space or I might be >> conflating it with the arm/aarch64 change. Tracking those down is natur= ally >> part of this work. >=20 > The glibc tests elf/tst-protected1{a,b}.c also need to be reviewed at > the same time. IIUC, the reason the patch above went in were to fix > failures on arm / aarch64 with those tests. I haven't yet worked out > whether all this is the same issue. >=20 > CC'ing Szabolcs. >=20 > Thanks, > Ramana >=20 >> >> jeff >=20