From: Florian Weimer <fw@deneb.enyo.de>
To: Nicholas Piggin via Libc-alpha <libc-alpha@sourceware.org>
Cc: Rich Felker <dalias@libc.org>,
Nicholas Piggin <npiggin@gmail.com>,
libc-dev@lists.llvm.org, linuxppc-dev@lists.ozlabs.org,
musl@lists.openwall.com
Subject: Re: [musl] Powerpc Linux 'scv' system call ABI proposal take 2
Date: Thu, 16 Apr 2020 22:18:18 +0200 [thread overview]
Message-ID: <87wo6fchh1.fsf@mid.deneb.enyo.de> (raw)
In-Reply-To: <1587004907.ioxh0bxsln.astroid@bobo.none> (Nicholas Piggin via Libc-alpha's message of "Thu, 16 Apr 2020 12:53:31 +1000")
* Nicholas Piggin via Libc-alpha:
> We may or may not be getting a new ABI that will use instructions not
> supported by old processors.
>
> https://sourceware.org/legacy-ml/binutils/2019-05/msg00331.html
>
> Current ABI continues to work of course and be the default for some
> time, but building for new one would give some opportunity to drop
> such support for old procs, at least for glibc.
If I recall correctly, during last year's GNU Tools Cauldron, I think
it was pretty clear that this was only to be used for intra-DSO ABIs,
not cross-DSO optimization. Relocatable object files have an ABI,
too, of course, so that's why there's a ABI documentation needed.
For cross-DSO optimization, the link editor would look at the DSO
being linked in, check if it uses the -mfuture ABI, and apply some
shortcuts. But at that point, if the DSO is swapped back to a version
built without -mfuture, it no longer works with those newly linked
binaries against the -mfuture version. Such a thing is a clear ABI
bump, and based what I remember from Cauldron, that is not the plan
here.
(I don't have any insider knowledge—I just don't want people to read
this think: gosh, yet another POWER ABI bump. But the PCREL stuff
*is* exciting!)
next prev parent reply other threads:[~2020-04-16 20:18 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-15 21:45 Nicholas Piggin
2020-04-15 22:55 ` [musl] " Rich Felker
2020-04-16 0:16 ` Nicholas Piggin
2020-04-16 0:48 ` Rich Felker
2020-04-16 2:24 ` Nicholas Piggin
2020-04-16 2:35 ` Rich Felker
2020-04-16 2:53 ` Nicholas Piggin
2020-04-16 3:03 ` Rich Felker
2020-04-16 3:41 ` Nicholas Piggin
2020-04-16 20:18 ` Florian Weimer [this message]
2020-04-16 9:58 ` Szabolcs Nagy
2020-04-20 0:27 ` Nicholas Piggin
2020-04-20 1:29 ` Rich Felker
2020-04-20 2:08 ` Nicholas Piggin
2020-04-20 21:17 ` Szabolcs Nagy
2020-04-21 9:57 ` Florian Weimer
2020-04-16 15:21 ` Jeffrey Walton
2020-04-16 15:40 ` Rich Felker
2020-04-16 4:48 ` Florian Weimer
2020-04-16 15:35 ` Rich Felker
2020-04-16 16:42 ` Florian Weimer
2020-04-16 16:52 ` Rich Felker
2020-04-16 18:12 ` Florian Weimer
2020-04-16 23:02 ` Segher Boessenkool
2020-04-17 0:34 ` Rich Felker
2020-04-17 1:48 ` Segher Boessenkool
2020-04-17 8:34 ` Florian Weimer
2020-04-16 14:16 ` Adhemerval Zanella
2020-04-16 15:37 ` Rich Felker
2020-04-16 17:50 ` Adhemerval Zanella
2020-04-16 17:59 ` Rich Felker
2020-04-16 18:18 ` Adhemerval Zanella
2020-04-16 18:31 ` Rich Felker
2020-04-16 18:44 ` Rich Felker
2020-04-16 18:52 ` Adhemerval Zanella
2020-04-20 0:46 ` Nicholas Piggin
2020-04-20 1:10 ` Nicholas Piggin
2020-04-20 1:34 ` Rich Felker
2020-04-20 2:32 ` Nicholas Piggin
2020-04-20 4:09 ` Rich Felker
2020-04-20 4:31 ` Nicholas Piggin
2020-04-20 17:27 ` Rich Felker
2020-04-22 6:18 ` Nicholas Piggin
2020-04-22 6:29 ` Nicholas Piggin
2020-04-23 2:36 ` Rich Felker
2020-04-23 12:13 ` Adhemerval Zanella
2020-04-23 16:18 ` Rich Felker
2020-04-23 16:35 ` Adhemerval Zanella
2020-04-23 16:43 ` Rich Felker
2020-04-23 17:15 ` Adhemerval Zanella
2020-04-23 17:42 ` Rich Felker
2020-04-25 3:40 ` Nicholas Piggin
2020-04-25 4:52 ` Rich Felker
2020-04-25 3:30 ` Nicholas Piggin
2020-04-21 12:28 ` David Laight
2020-04-21 14:39 ` Rich Felker
2020-04-21 15:00 ` Adhemerval Zanella
2020-04-21 15:31 ` David Laight
2020-04-22 6:54 ` Nicholas Piggin
2020-04-22 7:15 ` [musl] " Florian Weimer
2020-04-22 7:31 ` Nicholas Piggin
2020-04-22 8:11 ` Florian Weimer
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