Re: 64-bit shm: abi problems

Manfred (manfreds@colorfullife.com)
Mon, 13 Dec 1999 21:04:00 +0100

From: Christoph Rohland <hans-christoph.rohland@sap.com>
> "David S. Miller" <davem@redhat.com> writes:
> > You cannot simply change the ABI and still use the old system call
> > entry, this is not an option.
>
> On many platforms you probably do not need a new syscall. They use the
> sys_ipc demultiplexer and you can simply add a new sys_ipc command.
>
should we really add another function to the sys_ipc demultiplexer? Alpha
has normal syscalls, and all other architectures complain about the
"horrible hack".

I would propose that we add a new sysctl "shmget2()" with a "size_t size"
variable, and that we truncate the segment length for shmctl(IPC_GET) to
MAX_INT. The message queue code does that as well, and we can fix it
properly with the 32-bit UID patches.

Btw, both the Sparc64 and the PPC code still call "lock_kernel()" before
calling the ipc functions. The new ipc functions are thread safe, someone
could remove these calls.

--
    Manfred




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