Re: [PATCH] Start of compat32.h (again)

[Andi Kleen]

On Wed, Nov 27, 2002 at 09:00:53AM +0100, David Mosberger wrote:
> >>>>> On Wed, 27 Nov 2002 18:42:28 +1100, Stephen Rothwell <[e-mail]> said:
> 
>   Stephen> I make the follwing assumptions: returning s32 from a 32
>   Stephen> bit compatibility system call is the same as returning long
>   Stephen> or int.
> 
> That is not a safe assumption.  The ia64 ABI requires that a 32-bit
> result is returned in the least-significant 32 bits only---the upper
> 32 bits may contain garbage.  It should be safe to declare the syscall
> return type always as "long", no?

But the 32bit user space surely doesn't care about any garbage in 
the upper 32bits, no ?

64bit user space might, but that's not driven by a shared compat layer.

-Andi