Re: [PATCH] Document Linux's memory barriers
From: Alan Cox
Date: Wed Mar 08 2006 - 17:34:47 EST
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
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