From: Palmer Dabbelt <palmer@dabbelt.com>
To: joseph@codesourcery.com
Cc: libc-alpha@sourceware.org, Andrew Waterman <andrew@sifive.com>,
Darius Rad <darius@bluespec.com>,
dj@redhat.com
Subject: Re: RISC-V glibc port v2
Date: Wed, 20 Dec 2017 21:45:00 -0000 [thread overview]
Message-ID: <mhng-6a19beb5-ec9a-420c-ae28-bd8cfae5e3da@palmer-si-x1c4> (raw)
In-Reply-To: <alpine.DEB.2.20.1712202108120.9009@digraph.polyomino.org.uk>
On Wed, 20 Dec 2017 13:11:02 PST (-0800), joseph@codesourcery.com wrote:
> On Tue, 19 Dec 2017, Palmer Dabbelt wrote:
>
>> * Should we have padding in __pthread_rwlock_arch_t? I assume the padding on
>> other architectures is there for ABI reasons and shouldn't be necessary for
>> new ports, but the ports I usually rely on all have excatly the same padding
>> so I'm worried there's another reason for this.
>
> The size was probably originally chosen to be the same as used by
> Linuxthreads. Since then, there's been at least one rwlock rewrite that
> increased the amount of space that's padding.
>
> On the whole I'd say it's safest to have that padding on RISC-V as well,
> in case there are any more rewrites in future, since it's possible a
> rewrite could increase the amount of space used as well as decreasing it,
> and so if one architecture makes the type smaller than others that could
> complicate any such future change needing more space.
Sounds good. I'll add a comment
diff --git a/sysdeps/riscv/nptl/bits/pthreadtypes-arch.h b/sysdeps/riscv/nptl/bits/pthreadtypes-arch.h
index f15e024826ac..4fabc4a2cde2 100644
--- a/sysdeps/riscv/nptl/bits/pthreadtypes-arch.h
+++ b/sysdeps/riscv/nptl/bits/pthreadtypes-arch.h
@@ -52,6 +52,10 @@
#define __LOCK_ALIGNMENT
#define __ONCE_ALIGNMENT
+/* There is a lot of padding in this structure. While it's not strictly
+ necessary on RISC-V, we're going to leave it in to be on the safe side in
+ case it's needed in the future. Most other architectures have the padding,
+ so this gives us the same extensibility as everyone else has. */
struct __pthread_rwlock_arch_t
{
unsigned int __readers;
next prev parent reply other threads:[~2017-12-20 21:45 UTC|newest]
Thread overview: 76+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-20 7:23 Palmer Dabbelt
2017-12-20 7:23 ` [PATCH v2 05/15] RISC-V: Generic <string.h> Routines Palmer Dabbelt
2017-12-20 16:48 ` Joseph Myers
2017-12-23 22:01 ` Palmer Dabbelt
2018-01-01 0:52 ` Joseph Myers
2018-01-03 15:46 ` Adhemerval Zanella
2018-01-03 16:03 ` Joseph Myers
2018-01-03 16:08 ` Adhemerval Zanella
2017-12-20 7:23 ` [PATCH v2 03/15] RISC-V: Startup and Dynamic Loading Code Palmer Dabbelt
2017-12-20 16:38 ` Joseph Myers
2017-12-23 3:25 ` Palmer Dabbelt
2017-12-23 3:33 ` DJ Delorie
2017-12-23 12:52 ` Joseph Myers
2017-12-20 7:23 ` [PATCH v2 01/15] RISC-V: Build Infastructure Palmer Dabbelt
2017-12-20 14:05 ` Dmitry V. Levin
2017-12-20 20:25 ` Palmer Dabbelt
2017-12-20 16:22 ` Joseph Myers
2017-12-20 16:49 ` Adhemerval Zanella
2017-12-23 2:22 ` Palmer Dabbelt
2017-12-23 12:44 ` Joseph Myers
2017-12-25 20:58 ` Palmer Dabbelt
2018-01-01 1:21 ` Joseph Myers
2017-12-20 16:43 ` Joseph Myers
2017-12-23 3:41 ` Palmer Dabbelt
2017-12-23 12:53 ` Joseph Myers
2017-12-20 7:23 ` [PATCH v2 02/15] RISC-V: ABI Implementation Palmer Dabbelt
2017-12-20 16:31 ` Joseph Myers
2017-12-23 3:25 ` Palmer Dabbelt
2017-12-23 3:30 ` DJ Delorie
2017-12-20 7:23 ` [PATCH v2 04/15] RISC-V: Thread-Local Storage Support Palmer Dabbelt
2017-12-20 16:45 ` Joseph Myers
2017-12-23 19:10 ` Palmer Dabbelt
2017-12-20 7:24 ` [PATCH v2 08/15] RISC-V: RV32D, RV64F, and RV64D Support Palmer Dabbelt
2017-12-20 7:24 ` [PATCH v2 06/15] RISC-V: Generic <math.h> and soft-fp Routines Palmer Dabbelt
2017-12-20 16:50 ` Joseph Myers
2017-12-24 0:24 ` Palmer Dabbelt
2017-12-20 7:24 ` [PATCH v2 11/15] RISC-V: Linux ABI Palmer Dabbelt
2017-12-20 17:33 ` Joseph Myers
2017-12-25 19:47 ` Palmer Dabbelt
2018-01-01 1:04 ` Joseph Myers
2018-01-02 20:59 ` Joseph Myers
2017-12-20 7:24 ` [PATCH v2 14/15] Add linux-4.15 VDSO hash for RISC-V Palmer Dabbelt
2017-12-20 7:24 ` [PATCH v2 13/15] Add RISC-V dynamic relocations to elf.h Palmer Dabbelt
2017-12-20 7:24 ` [PATCH v2 09/15] RISC-V: Atomic and Locking Routines Palmer Dabbelt
2017-12-20 17:08 ` Joseph Myers
2017-12-24 1:26 ` Palmer Dabbelt
2017-12-20 7:24 ` [PATCH v2 12/15] RISC-V: Linux Startup and Dynamic Loading Code Palmer Dabbelt
2017-12-20 7:24 ` [PATCH v2 10/15] RISC-V: Linux Syscall Interface Palmer Dabbelt
2017-12-20 16:57 ` Adhemerval Zanella
2017-12-24 0:24 ` Palmer Dabbelt
2018-01-01 0:56 ` Joseph Myers
2018-01-03 13:43 ` Christoph Hellwig
2018-01-03 15:56 ` Adhemerval Zanella
2018-01-09 1:30 ` Palmer Dabbelt
2018-01-09 11:16 ` Adhemerval Zanella
2017-12-20 17:24 ` Joseph Myers
2017-12-25 19:47 ` Palmer Dabbelt
2017-12-20 7:24 ` [PATCH v2 07/15] RISC-V: RV32F Support Palmer Dabbelt
2017-12-20 17:01 ` Joseph Myers
2017-12-20 17:04 ` Joseph Myers
2017-12-24 1:26 ` Palmer Dabbelt
2017-12-24 0:37 ` Palmer Dabbelt
2018-01-01 0:57 ` Joseph Myers
2017-12-20 7:24 ` [PATCH v2 15/15] Add RISC-V to build-many-glibcs.py Palmer Dabbelt
2017-12-20 16:04 ` RISC-V glibc port v2 Joseph Myers
2017-12-20 20:25 ` Palmer Dabbelt
2017-12-20 20:42 ` Joseph Myers
2017-12-20 17:40 ` Joseph Myers
2017-12-25 20:20 ` Palmer Dabbelt
2018-01-01 1:20 ` Joseph Myers
2018-01-03 13:37 ` Christoph Hellwig
2018-01-03 13:42 ` Joseph Myers
2017-12-20 21:11 ` Joseph Myers
2017-12-20 21:45 ` Palmer Dabbelt [this message]
2017-12-25 12:57 ` Adhemerval Zanella
2018-01-01 0:58 ` Joseph Myers
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