Enabling and Disabling Interrupts

[Chris Rhodin <chris@notav8.com>]

On cpus without the ei/di instructions, the macros local_irq_enable and 
local_irq_disable use a read-modify-write of the status register to 
change the IE bit.  Doesn't this leave a window where an interrupting 
context can change the status registers interrupt mask bits and have 
that change reversed when the interrupted context resumes?  Or possibly 
this is covered by a policy I haven't figured out yet?
Thanks,

Chris Rhodin