tree ecf3548140022204214b20f6f69dfc67a6e026b9
parent bb7aa6d47fcd4f9ab18b4ade2ba078f7719f74ca
author Philippe Rétornaz <philippe.retornaz@epfl.ch> 1192056744 -0400
committer Haavard Skinnemoen <hskinnemoen@atmel.com> 1192102376 +0200

[AVR32] Fix random segfault with preemption

As explained on:
http://www.avrfreaks.net/index.php?nameÿphpBB2&fileÿewtopic&tS307
If the current process is preempted before it can copy RAR_SUP and
RSR_SUP both register are lost and the process will segfault as soon
as it return from the syscall since the return adress will be
corrupted.

This patch disable IRQ as soon as we enter the syscall path and
reenable them when the copy is done.

In the interrupt handlers, check if we are interrupting the srrf
instruction, if so disable interrupts and return. The interrupt
handler will be re-called immediatly when the interrupts are
reenabled.

After some stressing workload:
 - find / > /dev/null in loop
 - top (in ssh)
 - ping -f avr32

The segfaults are not seen anymore.

Signed-off-by: Philippe Rétornaz <philippe.retornaz@epfl.ch>
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>