From: "H. Peter Anvin" <hpa@kernel.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "H.J. Lu" <hjl.tools@gmail.com>,
linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
mingo@kernel.org, tglx@linutronix.de,
Paul Mundt <lethal@linux-sh.org>,
David Howells <dhowells@redhat.com>
Subject: Re: [PATCH 08/10] Use __kernel_ulong_t in struct msqid64_ds
Date: Thu, 17 May 2012 20:55:47 -0700 [thread overview]
Message-ID: <4FB5C843.9070002@kernel.org> (raw)
In-Reply-To: <CA+55aFxtejaM8ecOw8VYk74OaXfGY7=LO3JSyz3rdHEv2r9goQ@mail.gmail.com>
On 05/17/2012 08:49 PM, Linus Torvalds wrote:
> On Thu, May 17, 2012 at 8:39 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
>>
>> That will be wrong. __BITS_PER_LONG defines # bits of long
>> as seen by kernel. We don't use it in user space.
>
> Yes you do. Exactly in that structure that Peter points to. *Exactly*
> because that structure uses "long" instead of some fixed size. Which
> will be different in user mode than in kernel mode.
>
> And if user mode doesn't use these headers at all, then we should stop
> playing the insane games.
>
User mode can, and should, be able to use the exported headers. David
Howells have been doing even more work to distill out the actual
exported ABIs from the kernel and remove remaining chaff.
That being said it seems kind of loopy to expect something called
__BITS_PER_LONG to be anything other than (CHAR_BIT*sizeof(long)),
especially since one of the main uses of it seems to be sizing
bitvectors (which has its own issues on bigendian machines because I
think we do littleendian bit numbering even on bigendian iron).
-hpa
next prev parent reply other threads:[~2012-05-18 3:56 UTC|newest]
Thread overview: 77+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-17 22:13 [RFC PATCH 00/10] Use __kernel_[u]long_t for x32 user space compatibility H.J. Lu
2012-05-17 22:13 ` H.J. Lu
2012-05-17 22:13 ` [PATCH 01/10] Use __kernel_long_t in struct timex H.J. Lu
2012-05-17 22:13 ` H.J. Lu
2012-05-17 22:32 ` Linus Torvalds
2012-05-17 22:41 ` H. Peter Anvin
2012-05-17 22:50 ` H. Peter Anvin
2012-05-17 22:50 ` H. Peter Anvin
2012-05-17 22:50 ` Linus Torvalds
2012-05-17 22:55 ` H. Peter Anvin
2012-05-17 22:58 ` Linus Torvalds
2012-05-17 22:56 ` Linus Torvalds
2012-05-17 22:57 ` H. Peter Anvin
2012-05-17 23:51 ` David Daney
2012-05-17 22:13 ` [PATCH 02/10] Use __kernel_ulong_t in struct shm_info H.J. Lu
2012-05-17 22:13 ` [PATCH 03/10] Use __kernel_[u]long_t in linux/resource.h H.J. Lu
2012-05-17 22:13 ` H.J. Lu
2012-05-17 22:13 ` [PATCH 04/10] Use __kernel_long_t in struct msgbuf H.J. Lu
2012-05-17 22:13 ` H.J. Lu
2012-05-17 22:13 ` [PATCH 05/10] Use __kernel_long_t in struct mq_attr H.J. Lu
2012-05-17 22:13 ` H.J. Lu
2012-05-17 22:13 ` [PATCH 06/10] Use __kernel_ulong_t in x86 struct semid64_ds H.J. Lu
2012-05-17 22:13 ` [PATCH 07/10] Use __kernel_ulong_t in struct shmid64_ds/shminfo64 H.J. Lu
2012-05-17 22:13 ` H.J. Lu
2012-05-17 22:13 ` [PATCH 08/10] Use __kernel_ulong_t in struct msqid64_ds H.J. Lu
2012-05-17 22:13 ` H.J. Lu
2012-05-17 23:51 ` H. Peter Anvin
2012-05-18 0:07 ` Linus Torvalds
2012-05-18 0:07 ` Linus Torvalds
2012-05-18 0:14 ` H. Peter Anvin
2012-05-18 0:14 ` H. Peter Anvin
2012-05-18 0:22 ` Linus Torvalds
2012-05-18 0:27 ` H. Peter Anvin
2012-05-18 0:41 ` Linus Torvalds
2012-05-18 21:31 ` Arnd Bergmann
2012-05-18 21:41 ` H. Peter Anvin
2012-05-18 21:58 ` Arnd Bergmann
2012-05-18 22:08 ` H. Peter Anvin
2012-05-19 7:56 ` Arnd Bergmann
2012-05-19 14:35 ` Al Viro
2012-05-18 11:44 ` David Howells
2012-05-18 0:29 ` David Daney
2012-05-18 0:31 ` H. Peter Anvin
2012-05-18 0:45 ` David Daney
2012-05-18 0:37 ` H. Peter Anvin
2012-05-18 15:03 ` Chris Metcalf
2012-05-18 3:21 ` H. Peter Anvin
2012-05-18 3:39 ` H.J. Lu
2012-05-18 3:43 ` H.J. Lu
2012-05-18 3:47 ` H.J. Lu
2012-05-18 3:49 ` Linus Torvalds
2012-05-18 3:55 ` H. Peter Anvin [this message]
2012-05-18 3:59 ` H.J. Lu
2012-05-18 4:05 ` Linus Torvalds
2012-05-18 4:13 ` H.J. Lu
2012-05-18 21:21 ` Arnd Bergmann
2012-05-19 23:47 ` H. Peter Anvin
2012-05-20 1:32 ` H.J. Lu
2012-05-20 1:32 ` H.J. Lu
2012-05-20 2:08 ` H. Peter Anvin
2012-05-20 2:08 ` H. Peter Anvin
2012-05-18 3:56 ` H.J. Lu
2012-05-18 21:06 ` H. Peter Anvin
2012-05-18 11:53 ` David Howells
2012-05-18 12:06 ` H.J. Lu
2012-05-18 12:06 ` H.J. Lu
2012-05-17 22:13 ` [PATCH 09/10] Use __kernel_ulong_t in struct ipc64_perm H.J. Lu
2012-05-17 22:13 ` H.J. Lu
2012-05-17 22:13 ` [PATCH 10/10] Use __kernel_[u]long_t in x86-64 struct stat H.J. Lu
2012-05-17 23:07 ` [RFC PATCH 00/10] Use __kernel_[u]long_t for x32 user space compatibility David Daney
2012-05-17 23:07 ` David Daney
2012-05-17 23:11 ` H. Peter Anvin
2012-05-17 23:25 ` David Daney
2012-05-17 23:31 ` H. Peter Anvin
2012-05-18 0:19 ` Mike Frysinger
2012-05-18 0:21 ` H. Peter Anvin
2012-05-18 0:38 ` Mike Frysinger
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