Re: [PATCH] compatibility syscall layer (lets try again)

[Daniel Jacobowitz <dan@debian.org>]

On Wed, Dec 04, 2002 at 12:07:11PM -0800, Linus Torvalds wrote:
> 
> On Wed, 4 Dec 2002, george anzinger wrote:
> > 
> > As a suggestion for a solution for this, is it true that
> > regs, on a system call, will ALWAYS be at the end of the
> > stack?
> 
> No. Some architectures do not save enough state on the stack by default, 
> and need to do more to use do_signal(). Look at alpha, for example - the 
> default kernel stack doesn't contain all tbe registers needed, and 
> the alpha do_signal() calling convention is different.
> 
> If you want to handle do_signal(), then you need to do _all_ of this in 
> architecture-specific files. You simply cannot do what you want to do in a 
> generic way.

I think you should be able to call do_signal or a wrapper in some
platform-independent way.  Is the necessary information recoverable in
Alpha et al.?  What do you think of adding a standard wrapper function
so that system calls can process a signal if necessary?

Not only did George need this for POSIX conformance, I've seen a lot of
complaints about GDB interrupting sys_nanosleep even on cancelled
signals.

-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer