mirror of
https://github.com/Dasharo/zephyr.git
synced 2026-03-06 14:57:20 -08:00
820c94e5dd
The xtensa atomics layer was written with hand-coded assembly that had to be called as functions. That's needlessly slow, given that the low level primitives are a two-instruction sequence. Ideally the compiler should see this as an inline to permit it to better optimize around the needed barriers. There was also a bug with the atomic_cas function, which had a loop internally instead of returning the old value synchronously on a failed swap. That's benign right now because our existing spin lock does nothing but retry it in a tight loop anyway, but it's incorrect per spec and would have caused a contention hang with more elaborate algorithms (for example a spinlock with backoff semantics). Remove the old implementation and replace with a much smaller inline C one based on just two assembly primitives. This patch also contains a little bit of refactoring to address the scheme has been split out into a separate header for each, and the ATOMIC_OPERATIONS_CUSTOM kconfig has been renamed to ATOMIC_OPERATIONS_ARCH to better capture what it means. Signed-off-by: Andy Ross <andrew.j.ross@intel.com>