Summary:
- This commit introduces SP_WFE() and SP_SEV() to be used for spinlock
- Also, use wfe/sev instructions for ARMV7-A to reduce power consumption
Impact:
- ARMV7-a SMP only
Testing:
- sabre-6quad:smp (QEMU, dev board)
- maix-bit:smp, esp32-devkitc:smp, spresense:smp sim:smp (compile only)
Signed-off-by: Masayuki Ishikawa <Masayuki.Ishikawa@jp.sony.com>
libs/libc/pthread/pthread_spinlock.c: Resolve several TODO issues by accessing up_testset() via the boardctl() interface rather than attempting to call it directly.
configs/boardctl.c, include/sys/boardctl.h: Add access to architecture-specific up_testset() via boardctl().
arch/Kconfig's, sched/Kconfig, and include/nuttx/spinlock.h: Spinlocks are not available unless the architecture supports the up_testset() operation.
These APIs are used in sched_note.c to protect instumentation data.
The deffrence between these APIs to exsiting spin_lock() and spin_unlock()
is that they do not perform insturumentation to avoid recursive call
when SCHED_INSTRUMENTATION_SPINLOCKS=y.
Signed-off-by: Masayuki Ishikawa <Masayuki.Ishikawa@jp.sony.com>
In ARM document regarding memory barrires, SP_DMB() must be issued
before changing a spinlock state to SP_UNLOCKED. However, we found
that SP_DSB() is also needed to ensure that spin_unlock() works
correctly for network streaming aging test.
Signed-off-by: Masayuki Ishikawa <Masayuki.Ishikawa@jp.sony.com>
This commit corrects this. This is matching logic in sched_addreadytorun to avoid starting new tasks within the critical section (unless the CPU is the holder of the lock). The holder of the IRQ lock must be permitted to do whatever it needs to do.
