Re: [parisc-linux] what's up with the ipc syscalls?

From: JSO <soete.joel@tiscali.be>
To: Carlos O'Donell <carlos@baldric.uwo.ca>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
	Randolph Chung <randolph@tausq.org>,
	parisc-linux@lists.parisc-linux.org
Subject: Re: [parisc-linux] what's up with the ipc syscalls?
Date: Wed, 12 Nov 2003 19:54:14 +0000	[thread overview]
Message-ID: <3FB28FE6.2040908@tiscali.be> (raw)
In-Reply-To: <20031111214610.GJ18512@systemhalted>

Carlos O'Donell wrote:

>>I had some thoughts about the conversion stuff, I've added to work
>>around problems introduced because of the change of some structures in
>>glibc/kernel. I finally realized, that these conversion only works,
>>if the "old glibc" is still installed together with the old binary.
>>That's because the newer glibcs don't set the IPC_64 bit when doing 
>>the syscall, but the old binary still uses the wrong structs, so the
>>conversion routine never triggers. I think it's really time to remove that
>>crap. Below is an compiled but not booted patch, which removes it and also
>>forward ports the necessary bits in ipc/util.c from 2.4. 
>>    
>>
>
>The following things confuse me.
>
>a. Our glibc never set IPC_64, we had pass-thru assembly syscall
>   wrappers. Why? Because we don't have an IPC multiplexor, none of the
>   generic glibc code can be used by hppa.
>
>So I don't understand some of your comments about "old glibc setting
>IPC_64."
>
>  
>
>>If someone also wants to change glibc, feel free. I still think changing
>>glibc is a bad idea, because this new glibc won't work with a current 2.4
>>kernel.
>>    
>>
>
>I believed we had the following scenario:
>
>a. Old glibc never called with IPC_64.
>b. Kernel turned IPC_64 on for us so we get the new style structs.
>c. Apps get new style structs without calling IPC_64.
>
>Now we wish to have the hack in the kernel removed, but apps exist that
>expect newstyle structs without calling IPC_64. Thus glibc has to
>call the syscall with IPC_64 to get the right value back to userspace.
>
>AFAIK the following is required:
>
>a. Remove kernel hacks (Thanks Thomas!).
>  
>
So I test it successfuly with 2.4 on my b2k (just re-compile the kernel, 
ssh remote connection, rsync ft, ...) :)
Sorry no more time try 2.6 on a b180 :(

>b. Add glibc code to turn IPC_64 on for all the afflicted syscalls.
>c. Eventually when all the apps disappear we can toss out the code from
>   glibc.
>
>Thomas, did I get this right?
>
>Cheers,
>Carlos.
>
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>  
>