Chris Zankel c0e50d4112 xtensa: fix fast_syscall_spill_registers
The original implementation could clobber registers under certain conditions.

The Xtensa processor architecture uses windowed registers and the original
implementation was using a4 as a temporary register, which under certain
conditions could be register a0 of the oldest window frame, and didn't always
restore the content correctly.

By moving the _spill_registers routine inside the fast system call, it frees
up one more register (the return address is not required anymore) for the
spill routine.

Signed-off-by: Chris Zankel <chris@zankel.net>
2014-01-29 13:47:26 -08:00
..
2014-01-15 00:27:03 +04:00
2013-09-06 09:48:29 -07:00