ia64_cmpxchg on United Linux 1.0

ia64_cmpxchg on United Linux 1.0

[Umut Aymakoglu]

Hi -
   The macro used for test_and_set (ia64_cmpxchg) asm/atomic.h or
asm/spinlock.h on United Linux 1.0 is under #ifdef _KERNEL_  and therefore
can not be used in  user applications.  In RHAT 2.1 it was not under #ifdef
_KERNEL_ . Is there another macro for test_and_set  that user applications
can use?

thanks,
Umut

RE: ia64_cmpxchg on United Linux 1.0

[Boehm, Hans]

You might want to look at the atomic operations package that's included
here: http://www.hpl.hp.com/research/linux/qprof/download.php4 .

This isn't exactly a mature package, but I'm trying to get it there.
IA64 is relatively well-supported.  And AFAIK, it's the only such package
that handles memory barriers explicitly and correctly (at least by
my definition of "correctly" :-) ).

Suggestions/bug reports/patches are welcome.

Hans

> -----Original Message-----
> From: Umut Aymakoglu [mailto:umuta@us.ibm.com]
> Sent: Tuesday, September 30, 2003 3:39 PM
> To: linux-ia64@vger.kernel.org
> Subject: ia64_cmpxchg on United Linux 1.0
> 
> 
> 
> 
> 
> 
> Hi -
>    The macro used for test_and_set (ia64_cmpxchg) asm/atomic.h or
> asm/spinlock.h on United Linux 1.0 is under #ifdef _KERNEL_  
> and therefore
> can not be used in  user applications.  In RHAT 2.1 it was 
> not under #ifdef
> _KERNEL_ . Is there another macro for test_and_set  that user 
> applications
> can use?
> 
> thanks,
> Umut
> 
> -
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Re: ia64_cmpxchg on United Linux 1.0

[Jim Wilson]

On Tue, 2003-09-30 at 15:38, Umut Aymakoglu wrote:
>  Is there another macro for test_and_set  that user applications
> can use?

The psABI defines a set of synchronization primitives in section 7.3. 
The psABI is available from the Intel IPF web site.
	http://developer.intel.com/design/itanium/arch_spec.htm

Gcc implements these primitives in the ia64intrin.h file.  This header
file should be available with any system that has gcc installed on it. 
It is found in the gcc install directory, probably under /usr/lib.

These are very basic primitives that expand to single IPF instructions. 
They won't be very useful unless you know what you are doing.  You might
be better off using libraries implemented on top of these primitives.

These primitives aren't used much.  HJ found a couple of simple type
errors in them when he looked at them earlier this year.  The patches
for these problems will be in gcc-3.4 which hasn't been released yet. 
They should be trivial to backpatch into older gcc releases if you need
them.
-- 
Jim Wilson, GNU Tools Support, http://www.SpecifixInc.com