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From: Szabolcs Nagy <szabolcs.nagy@arm.com>
To: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Cc: Florian Weimer <fweimer@redhat.com>,
	Adhemerval Zanella via Libc-alpha <libc-alpha@sourceware.org>
Subject: Re: [PATCH 20/28] aarch64: Add glibc-hwcaps support
Date: Wed, 14 Oct 2020 15:37:51 +0100	[thread overview]
Message-ID: <20201014143750.GF3819@arm.com> (raw)
In-Reply-To: <3a7b2533-e6c7-5ded-2d94-b1b5c41de424@linaro.org>

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  <adhemerval.zanella@linaro.org>
> > 
> > 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.

  reply	other threads:[~2020-10-14 14:38 UTC|newest]

Thread overview: 103+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-01 16:31 [PATCH 00/28] " Florian Weimer
2020-10-01 16:31 ` [PATCH 01/28] elf: Do not search HWCAP subdirectories in statically linked binaries Florian Weimer
2020-10-01 18:22   ` Adhemerval Zanella
2020-10-01 18:24     ` Carlos O'Donell
2020-10-01 18:29       ` Adhemerval Zanella
2020-10-01 20:24         ` Carlos O'Donell
2020-10-01 16:31 ` [PATCH 02/28] elf: Implement __rtld_malloc_is_full Florian Weimer
2020-10-01 18:23   ` Adhemerval Zanella
2020-10-08  9:44     ` Florian Weimer
2020-10-01 16:31 ` [PATCH 03/28] elf: Implement _dl_write Florian Weimer
2020-10-05 19:46   ` Adhemerval Zanella
2020-10-01 16:31 ` [PATCH 04/28] elf: Extract command-line/environment variables state from rtld.c Florian Weimer
2020-10-06 20:45   ` Adhemerval Zanella
2020-10-08 11:32     ` Florian Weimer
2020-10-01 16:32 ` [PATCH 05/28] elf: Move ld.so error/help output to _dl_usage Florian Weimer
2020-10-06 21:06   ` Adhemerval Zanella
2020-10-08 12:19     ` Florian Weimer
2020-10-01 16:32 ` [PATCH 06/28] elf: Record whether paths come from LD_LIBRARY_PATH or --library-path Florian Weimer
2020-10-07 16:39   ` Adhemerval Zanella
2020-10-07 16:49     ` Florian Weimer
2020-10-01 16:32 ` [PATCH 07/28] elf: Implement ld.so --help Florian Weimer
2020-10-07 17:16   ` Adhemerval Zanella
2020-10-08 13:13     ` Florian Weimer
2020-10-01 16:32 ` [PATCH 08/28] elf: Implement ld.so --version Florian Weimer
2020-10-07 18:36   ` Adhemerval Zanella
2020-10-07 18:38     ` Adhemerval Zanella
2020-10-08 13:37     ` Florian Weimer
2020-10-01 16:32 ` [PATCH 09/28] scripts/update-copyrights: Update csu/version.c, elf/dl-usage.c Florian Weimer
2020-10-07 18:41   ` Adhemerval Zanella
2020-10-01 16:32 ` [PATCH 10/28] elf: Use the term "program interpreter" in the ld.so help message Florian Weimer
2020-10-07 21:08   ` Adhemerval Zanella
2020-10-08 14:08     ` Florian Weimer
2020-10-01 16:32 ` [PATCH 11/28] elf: Print the full name of the dynamic loader " Florian Weimer
2020-10-08 12:38   ` Adhemerval Zanella
2020-10-01 16:32 ` [PATCH 12/28] elf: Make __rtld_env_path_list and __rtld_search_dirs global variables Florian Weimer
2020-10-08 13:27   ` Adhemerval Zanella
2020-10-01 16:32 ` [PATCH 13/28] elf: Add library search path information to ld.so --help Florian Weimer
2020-10-08 16:22   ` Adhemerval Zanella
2020-10-01 16:33 ` [PATCH 14/28] elf: Enhance ld.so --help to print HWCAP subdirectories Florian Weimer
2020-10-08 16:27   ` Adhemerval Zanella
2020-10-09  8:18     ` Florian Weimer
2020-10-09 13:49   ` Matheus Castanho
2020-10-09 17:08     ` Florian Weimer
2020-10-09 17:12       ` Florian Weimer
2020-10-09 18:54         ` Matheus Castanho
2020-10-12  9:47           ` Florian Weimer
2020-10-01 16:33 ` [PATCH 15/28] elf: Do not pass GLRO(dl_platform), GLRO(dl_platformlen) to _dl_important_hwcaps Florian Weimer
2020-10-08 18:04   ` Adhemerval Zanella
2020-10-01 16:33 ` [PATCH 16/28] elf: Add glibc-hwcaps support for LD_LIBRARY_PATH Florian Weimer
2020-10-08 10:13   ` Szabolcs Nagy
2020-10-09  9:08     ` Florian Weimer
2020-10-09 10:50       ` Szabolcs Nagy
2020-10-09 10:55         ` Florian Weimer
2020-10-09 11:03           ` Szabolcs Nagy
2020-10-08 23:16   ` Paul A. Clarke
2020-10-09  8:56     ` Florian Weimer
2020-10-09 13:19   ` Adhemerval Zanella
2020-10-12 11:54     ` Florian Weimer
2020-10-01 16:33 ` [PATCH 17/28] x86_64: Add glibc-hwcaps support Florian Weimer
2020-10-01 16:33 ` [PATCH 18/28] powerpc64le: " Florian Weimer
2020-10-01 18:56   ` Paul A. Clarke
2020-10-05  9:47     ` Florian Weimer
2020-10-05 19:15       ` Paul A. Clarke
2020-10-06 12:20         ` Florian Weimer
2020-10-06 17:45           ` Paul A. Clarke
2020-10-09  9:06             ` Florian Weimer
2020-10-01 16:33 ` [PATCH 19/28] s390x: Add " Florian Weimer
2020-10-01 16:33 ` [PATCH 20/28] aarch64: " Florian Weimer
2020-10-14 13:46   ` Adhemerval Zanella
2020-10-14 14:08     ` Florian Weimer
2020-10-14 14:15       ` Adhemerval Zanella
2020-10-14 14:37         ` Szabolcs Nagy [this message]
2020-10-14 14:43           ` Adhemerval Zanella
2020-10-14 15:13             ` Florian Weimer
2020-10-14 14:44           ` Florian Weimer
2020-10-14 15:09             ` Szabolcs Nagy
2020-10-01 16:33 ` [PATCH 21/28] elf: Add endianness markup to ld.so.cache Florian Weimer
2020-10-14 14:07   ` Adhemerval Zanella
2020-10-01 16:33 ` [PATCH 22/28] elf: Add extension mechanism " Florian Weimer
2020-10-15 17:52   ` Adhemerval Zanella
2020-10-30 12:22     ` Florian Weimer
2020-11-03 12:45       ` Adhemerval Zanella
2020-11-03 15:30         ` Florian Weimer
2020-10-01 16:34 ` [PATCH 23/28] elf: Unify old and new format cache handling code in ld.so Florian Weimer
2020-10-16 14:37   ` Adhemerval Zanella
2020-10-30 13:22     ` Florian Weimer
2020-11-03 13:02       ` Adhemerval Zanella
2020-10-01 16:34 ` [PATCH 24/28] elf: Implement a string table for ldconfig, with tail merging Florian Weimer
2020-10-20 14:25   ` Adhemerval Zanella
2020-10-30 17:08     ` Florian Weimer
2020-11-03 13:05       ` Adhemerval Zanella
2020-11-03 15:29         ` Florian Weimer
2020-10-01 16:34 ` [PATCH 25/28] elf: Implement tail merging of strings in ldconfig Florian Weimer
2020-10-22 21:08   ` Adhemerval Zanella
2020-10-30 17:36     ` Florian Weimer
2020-10-01 16:34 ` [PATCH 26/28] elf: In ldconfig, extract the new_sub_entry function from search_dir Florian Weimer
2020-10-27 13:15   ` Adhemerval Zanella
2020-10-01 16:34 ` [PATCH 27/28] elf: Process glibc-hwcaps subdirectories in ldconfig Florian Weimer
2020-10-27 17:28   ` Adhemerval Zanella
2020-11-04 11:57     ` Florian Weimer
2020-10-01 16:34 ` [PATCH 28/28] elf: Add glibc-hwcaps subdirectory support to ld.so cache processing Florian Weimer
2020-10-01 16:50 ` [PATCH 00/28] glibc-hwcaps support H.J. Lu
2020-10-01 16:54   ` Florian Weimer

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