Re: RFC: userspace exception fixups

[Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>]

On Thu, Nov 01, 2018 at 10:53:40AM -0700, Andy Lutomirski wrote:
> If a handler is registered, then, if a synchronous exception happens
> (page fault, etc), the kernel would set up an exception frame as usual
> but, rather than checking for signal handlers, it would just call the
> registered handler.  That handler is expected to either handle the
> exception entirely on its own or to call one of two new syscalls to
> ask for normal signal delivery or to ask to retry the faulting
> instruction.

Why the syscalls are required? Couldn't the handler have just a return
value to indicate the appropriate action?

Another thing that I'm wondering is that what if a signal occurs inside
the exception handler?

/Jarkko