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DIR:OUT; SFP:1101; X-OriginatorOrg: arm.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 14 Oct 2020 14:38:25.0079 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 08bb1e47-9a5c-4081-4fac-08d8704ecead X-MS-Exchange-CrossTenant-Id: f34e5979-57d9-4aaa-ad4d-b122a662184d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=f34e5979-57d9-4aaa-ad4d-b122a662184d; Ip=[63.35.35.123]; Helo=[64aa7808-outbound-1.mta.getcheckrecipient.com] X-MS-Exchange-CrossTenant-AuthSource: DB5EUR03FT016.eop-EUR03.prod.protection.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: AM0PR08MB5505 X-Spam-Status: No, score=-8.7 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, MSGID_FROM_MTA_HEADER, RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H2, SPF_HELO_PASS, SPF_PASS, TXREP, UNPARSEABLE_RELAY autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 14 Oct 2020 14:38:29 -0000 The 10/14/2020 11:15, Adhemerval Zanella via Libc-alpha wrote: > On 14/10/2020 11:08, Florian Weimer wrote: > > * Adhemerval Zanella via Libc-alpha: > >> On 01/10/2020 13:33, Florian Weimer via Libc-alpha wrote: > >>> At this point, only the "atomics" subdirectory is available, > >>> for libraries built using LSE atomics. > >> > >> LGTM, thanks. > >> > >> Reviewed-by: Adhemerval Zanella > > > > Thanks. I didn't want to skip AArch64, but it's really more of a stub > > implementation: > > > >>> +const char _dl_hwcaps_subdirs[] = "atomics"; > > > > Does this still make sense with GCC defaulting to -moutline-atomics for > > ARMv8a? That's what I wonder. > > > > Eventually, we need to define some levels for AArch64, and I'm not sure > > to what extent they would align with the official 8.X versions. To me, > > they look more like a bouquet you can choose from. > > I am not sure how ARM maintainers would like to handle it, either by > defining based on ARMv8.x revisions, a subsets of HWCAP capabilities, > or by not defining anything. > > For now I think the atomic makes sense because of -moutline-atomics, > although it is essentially ARMv8.1. the atomics path logic was added in glibc 2.28 in commit 397c54c1afa531242602fe3ac7bb47eff0e909f9 (see the reasoning in the commit message). since then this is public api that users may rely on (although likely there are not many users..) so i dont want to remove it (and yes it's not very helpful now that outline-atomics is the default in gcc). otoh i did not review this patch when it was posted because i wanted the return value to not be a signed int when it is a bit mask.