ARMV7: threading support for cooperative multitasking

These functions add support for cooperative multitasking.
Currently, since we only have one ARM SOC that uses or supports multitasking,
arch_get_thread_stackbase returns CONFIG_STACK_BOTTOM for the thread stack.
We may end up having to make a cpu-specific function that arch_get_thread_stackbase calls,
but let's avoid adding complexity until we're sure we need to. We also wish to avoid
creating Yet Another Config Variable but will do so if pressed.

The switch code only saves r4-r11 and lr, which is consistent with the standard.

Change-Id: I0338a9c11127351e1f3a190bc51a7a558420b141
Signed-off-by: Ronald G. Minnich <rminnich@gmail.com>
Reviewed-on: https://gerrit.chromium.org/gerrit/66845
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Commit-Queue: Ronald G. Minnich <rminnich@chromium.org>
Tested-by: Ronald G. Minnich <rminnich@chromium.org>
(cherry picked from commit 22b62af3c26b6b504498b434d29a56a8932f3061)
Signed-off-by: Isaac Christensen <isaac.christensen@se-eng.com>
Reviewed-on: http://review.coreboot.org/6517
Tested-by: build bot (Jenkins)

0 files changed, 0 insertions, 0 deletions