Re: [PATCH 0/3] clone64() and unshare64() system calls

From: H. Peter Anvin
Date: Wed Apr 09 2008 - 21:14:49 EST


sukadev@xxxxxxxxxx wrote:

If you're going to make it a 64-bit pass it in as a 64-bit number, instead of breaking it into two numbers.

Maybe I am missing your point. The glibc interface could take a 64bit
parameter, but don't we need to pass 32-bit values into the system call on 32 bit systems ?

Not as such, no. The ABI handles that. To make the ABI clean on some architectures, it's good to consider a 64-bit value only in positions where they map to an even:odd register pair once slotted in.

Yes, this was discussed before in the context of Pavel Emelyanov's patch

http://lkml.org/lkml/2008/1/16/109

along with sys_indirect(). While there was no consensus, it looked like
adding a new system call was better than open ended interfaces.

That's not really an open-ended interface, it's just an expandable bitmap.

-hpa
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