Universal Regs address

Universal Regs address

[george anzinger]

&regs is needed by the deliver signal code and currently is supplied by
the system call interface to the system calls that need it.  This
requires that any new system call to have (at least in some archs)
special code in the system call trap area to pass the &regs, or does it?

In an arch in which the call stack address decreases as calls are made,
isn't:

&regs = stack_base+size of(stack) - size of(struct regs);

an for stacks that increase:

&regs = stack_base;

The only time this would not be true, unless I am missing something, is
if the system call is made from kernel space.  Is this an issue?  Do we
ever need &regs if called from the kernel?  If not, can we tell the call
was from the kernel?

comments?
-- 
George           george@mvista.com
High-res-timers: http://sourceforge.net/projects/high-res-timers/
Real time sched: http://sourceforge.net/projects/rtsched/