Re: [PATCH] Document Linux's memory barriers

Alan Cox
2006-03-08T22:37:15Z

On Iau, 2006-03-09 at 09:06 +1100, Paul Mackerras wrote:
> I'd be interested to know what the C standard says about whether the
> compiler can reorder writes that may be visible to a signal handler.
> An interrupt handler in the kernel is logically equivalent to a signal
> handler in normal C code.

The C standard doesn't have much to say. POSIX has a lot to say and yes
it can do this. You do need volatile or store barriers in signal touched
code quite often, or for that matter locks

POSIX/SuS also has stuff to say about what functions are signal safe and
what is not allowed.

Alan