[hppa-linux] syscall work

[Stan Sieler]

Hi,

There may be a reason to avoid the GATE instruction...I've seen some
HP PA-RISC systems where GATE has given way to simply
marking the "gateway" page as non-executable, and relying on a trap
handler to detect the gateway access.  The final result is the same...
an architected method of doing a system call.  (I can only conjecture 
that there is a reason for this...but I don't know what it is.)

Perhaps we can get an HP person to comment?

> It does not matter as long as the gateway instruction is on the "special"
> page. Probably one wants to put a nop before the gateway instruction.

-- 
Stan Sieler                                          sieler@allegro.com
                                     http://www.allegro.com/sieler.html