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From: Ulrich Drepper <drepper@redhat.com>
To: davidm@hpl.hp.com
Cc: libc-hacker@sources.redhat.com, davidm@napali.hpl.hp.com
Subject: Re: fix ia64 longjmp() to work from alternate signal-stack
Date: Thu, 26 Aug 2004 09:24:00 -0000	[thread overview]
Message-ID: <412DAC31.1050404@redhat.com> (raw)
In-Reply-To: <16684.49335.802840.212013@napali.hpl.hp.com>

David Mosberger wrote:

> If there are no objections, please apply this patch.

I don't like this.  The behavior of longjmp if the starting point is
using the alternate stack while the destination uses the normal stack,
is currently unspecified in POSIX.  I've asked for clarification in the
POSIX working group.  The result I expect is "don't do it", aka,
unspecified.

So, this is no case the normal setjmp/longjmp needs to handle.

For the unwind/cancellation handling this might not apply.  But it is an
implementation decision to use setjmp/longjmp.  So, the solution should
be to use special versions of those interfaces in the nptl
implementation.  For all platforms but ia64 the new names are just
aliases of the normal code.  For ia64 this heavier code is used.  This
will also take care of most of the performance penalties since they
don't apply in general, only in the thread code.

-- 
➧ Ulrich Drepper ➧ Red Hat, Inc. ➧ 444 Castro St ➧ Mountain View, CA ❖

  reply	other threads:[~2004-08-26  9:24 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-08-25 16:39 David Mosberger
2004-08-26  9:24 ` Ulrich Drepper [this message]
2004-08-26  9:37   ` David Mosberger
2004-08-31 15:10   ` David Mosberger
2004-08-31 15:31     ` Ulrich Drepper
2004-08-31 16:14       ` David Mosberger
2004-08-31 16:20         ` Jakub Jelinek
2004-09-01  8:52           ` David Mosberger
2004-09-02 22:50             ` Ulrich Drepper
2004-09-07 17:36               ` David Mosberger
2004-09-13 17:36                 ` David Mosberger
2004-09-13 18:39                   ` Ulrich Drepper
2004-09-14 17:01                     ` David Mosberger
2004-08-31 16:20         ` Ulrich Drepper

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