From: Vineet Gupta <vineet.gupta1@synopsys.com>
To: Joseph Myers <joseph@codesourcery.com>
Cc: Adhemerval Zanella <adhemerval.zanella@linaro.org>,
<libc-alpha@sourceware.org>, <linux-snps-arc@lists.infradead.org>
Subject: Re: [PATCH 09/21] ARC: Linux ABI
Date: Fri, 21 Dec 2018 15:06:11 -0800 [thread overview]
Message-ID: <f7671ddd-c417-df8f-cee1-b010d2a7a062@synopsys.com> (raw)
In-Reply-To: <alpine.DEB.2.21.1812192024320.2810@digraph.polyomino.org.uk>
On 12/19/18 12:36 PM, Joseph Myers wrote:
> On Wed, 19 Dec 2018, Vineet Gupta wrote:
>
>> So perhaps we keep the ARC header above, with matching layout, while
>> switching to generic sigaction() still. OK ?
>
> If the different userspace layout is better, it should be better for all
> future ports as well.
>
> Duplicating all the SA_* constants in architecture-specific headers, even
> when those architectures don't actually have different values of those
> constants, is bad, especially since there is logic about which __USE_*
> macros get which SA_* defined which then needs to be duplicated.
Totally agree.
> So what this suggests to me is a preliminary patch series to unify
> bits/sigaction.h headers - there might be one header for SA_* constants
> (architecture-specific variants only when needed), one for SIG_* constants
> (architecture-specific variants only when needed), and one for the ways in
> which the layout of the userspace struct sigaction can vary (defining
> macros that the unified bits/sigaction.h then uses to control the layout -
> cf. the siginfo unification a while back).
Actually this can be simplified. Given the asm-generic syscall ABI, we are anyhow
locked into SA_* or SIG_* and kernel side sigaction, the only variant is user
facing struct sigaction. I suppose we could leave it at that given that only 1
syscall sigaction is affected. The bigger bang for the buck will the reduction of
sizeof(sigset_t) - purely from amount of memory any sig* call needs to
read/write/copy.
I'll follow Adhemerval's suggestion of arch-specific __sigset_t.h which seems
doable w/o much pain.
> Initially, the default version of that last header would correspond to the
> existing sysdeps/unix/sysv/linux/bits/sigaction.h header - however, if you
> get consensus for a different layout as the default for new architectures,
> the default would change and all existing architectures that use the
> current default layout would get copies of the new bits/ header configured
> to keep the old layout. (Variants are possible to reduce the number of
> architectures needing architecture-specific copies as a result of the
> changed default. For example, you could have the new default only in
> sysdeps/unix/sysv/linux/generic not sysdeps/unix/sysv/linux/ and then only
> existing asm-generic architectures (aarch64 nios2 riscv) would need to
> override back to the old default layout.)
Yes this will require a needless churn all over, just for 1 syscall.
next prev parent reply other threads:[~2018-12-21 23:06 UTC|newest]
Thread overview: 99+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-18 21:04 [PATCH 00/21] glibc port to ARC processors Vineet Gupta
2018-12-18 21:04 ` [PATCH 01/21] longlong.h: sync from gcc to fix ARC inline asm constraints Vineet Gupta
2018-12-18 22:56 ` Joseph Myers
2018-12-18 23:11 ` Vineet Gupta
2018-12-21 18:46 ` Joseph Myers
2018-12-21 19:07 ` Vineet Gupta
2018-12-18 21:04 ` [PATCH 02/21] ARC: add definitions to elf/elf.h Vineet Gupta
2018-12-18 21:04 ` [PATCH 03/21] ARC: ABI Implementation Vineet Gupta
2018-12-18 23:09 ` Joseph Myers
2018-12-19 2:00 ` Vineet Gupta
2018-12-19 17:40 ` Joseph Myers
2018-12-19 20:20 ` Vineet Gupta
2018-12-19 20:37 ` Joseph Myers
2019-01-28 23:03 ` ARC binutils init/fini (was Re: [PATCH 03/21] ARC: ABI Implementation) Vineet Gupta
2019-01-28 23:13 ` Joseph Myers
2019-01-28 23:42 ` Vineet Gupta
2018-12-18 21:04 ` [PATCH 04/21] ARC: startup and dynamic linking code Vineet Gupta
2018-12-18 23:24 ` Joseph Myers
2018-12-19 0:52 ` Vineet Gupta
2018-12-18 21:04 ` [PATCH 05/21] ARC: Thread Local Storage support Vineet Gupta
2018-12-18 21:04 ` [PATCH 06/21] ARC: Atomics and Locking primitives Vineet Gupta
2018-12-18 23:15 ` Joseph Myers
2019-01-15 0:40 ` Vineet Gupta
2018-12-18 21:04 ` [PATCH 07/21] ARC: math soft float support Vineet Gupta
2018-12-18 23:23 ` Joseph Myers
2018-12-19 0:01 ` Joseph Myers
2018-12-20 21:35 ` Vineet Gupta
2018-12-21 1:08 ` Vineet Gupta
2018-12-21 1:19 ` Joseph Myers
2018-12-18 21:04 ` [PATCH 08/21] ARC: Linux Syscall Interface Vineet Gupta
2018-12-18 23:30 ` Joseph Myers
2018-12-19 2:39 ` Vineet Gupta
2018-12-19 17:58 ` ARC vs. generic sigaction (was Re: [PATCH 08/21] ARC: Linux Syscall Interface) Vineet Gupta
2018-12-19 18:07 ` Joseph Myers
2018-12-19 22:00 ` Adhemerval Zanella
2018-12-19 22:23 ` Vineet Gupta
2018-12-20 11:19 ` Adhemerval Zanella
2018-12-20 12:06 ` Arnd Bergmann
2018-12-20 19:25 ` Vineet Gupta
2018-12-20 12:40 ` Florian Weimer
2018-12-20 18:48 ` Vineet Gupta
2019-01-03 13:10 ` Florian Weimer
2018-12-20 19:23 ` Vineet Gupta
2018-12-20 20:06 ` Adhemerval Zanella
2018-12-20 20:46 ` Vineet Gupta
2018-12-21 12:05 ` Adhemerval Zanella
2019-01-09 21:49 ` Vineet Gupta
2018-12-18 21:04 ` [PATCH 09/21] ARC: Linux ABI Vineet Gupta
2018-12-18 23:38 ` Joseph Myers
2018-12-19 19:57 ` Vineet Gupta
2018-12-19 20:36 ` Joseph Myers
2018-12-21 23:06 ` Vineet Gupta [this message]
2018-12-18 21:04 ` [PATCH 10/21] ARC: Linux Startup and Dynamic Loading Vineet Gupta
2018-12-18 23:49 ` Joseph Myers
2018-12-19 20:26 ` Vineet Gupta
2018-12-18 21:04 ` [PATCH 11/21] ARC: ABI lists Vineet Gupta
2018-12-18 22:31 ` Andreas Schwab
2018-12-18 22:32 ` Vineet Gupta
2018-12-18 21:04 ` [PATCH 12/21] ARC: Update syscall-names.list for ARC specific syscalls Vineet Gupta
2018-12-18 21:26 ` Florian Weimer
2018-12-18 21:29 ` Vineet Gupta
2018-12-19 8:16 ` Florian Weimer
2018-12-18 21:04 ` [PATCH 13/21] ARC: Build Infrastructure Vineet Gupta
2018-12-18 23:44 ` Joseph Myers
2018-12-19 21:58 ` Vineet Gupta
2018-12-19 22:17 ` Joseph Myers
2018-12-20 23:21 ` Vineet Gupta
2018-12-20 23:24 ` Joseph Myers
2019-01-29 23:36 ` Vineet Gupta
2018-12-18 21:04 ` [PATCH 14/21] ARC: Enable __start as entry point vs. canonical _start Vineet Gupta
2018-12-18 21:28 ` Florian Weimer
2018-12-18 21:31 ` Vineet Gupta
2018-12-18 22:59 ` Joseph Myers
2018-12-18 23:08 ` Vineet Gupta
2018-12-19 20:36 ` Vineet Gupta
2018-12-18 21:04 ` [PATCH 15/21] ARC: testsuite fix: elf/check-initfini Vineet Gupta
2018-12-18 21:04 ` [PATCH 16/21] ARC: testsuite fix: sysvipc/* Vineet Gupta
2018-12-19 22:10 ` Adhemerval Zanella
2018-12-18 21:04 ` [PATCH 17/21] ARC: testsuite fix: stdlib/tst-makecontext Vineet Gupta
2018-12-18 22:36 ` Andreas Schwab
2019-01-21 22:32 ` Vineet Gupta
2018-12-18 21:04 ` [PATCH 18/21] ARC: testsuite fix: GD TLS issue Vineet Gupta
2018-12-18 21:04 ` [PATCH 19/21] ARC: fix several unwining and cancelation tests Vineet Gupta
2018-12-18 21:04 ` [PATCH 20/21] build-many-glibcs.py: Enable ARC builds Vineet Gupta
2018-12-18 21:04 ` [PATCH 21/21] NEWS: mention ARC port Vineet Gupta
2018-12-18 23:45 ` Joseph Myers
2018-12-19 18:30 ` Vineet Gupta
2018-12-18 22:52 ` [PATCH 00/21] glibc port to ARC processors Joseph Myers
2018-12-18 23:07 ` Vineet Gupta
2018-12-18 23:52 ` Joseph Myers
2018-12-21 1:55 ` Vineet Gupta
2018-12-21 14:32 ` Joseph Myers
2018-12-21 17:36 ` Vineet Gupta
2018-12-18 23:11 ` Joseph Myers
2018-12-19 23:45 ` Vineet Gupta
2018-12-20 0:14 ` Joseph Myers
2018-12-20 0:51 ` Vineet Gupta
2018-12-20 21:22 ` test related questions (was Re: [PATCH 00/21] glibc port to ARC processors) Vineet Gupta
2018-12-20 21:59 ` Joseph Myers
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