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> |
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| .. | ||
| atomic.rst | ||
| cpu_idle.rst | ||
| cxx_support.rst | ||
| fatal.rst | ||
| float.rst | ||
| interrupts.rst | ||
| polling.rst | ||
| ring_buffers.rst | ||
| version.rst | ||