Soby Mathew c97cba4ea4 Fix the CAS spinlock implementation ... Make the spinlock implementation use ARMv8.1-LSE CAS instruction based on a platform build option. The CAS-based implementation used to be unconditionally selected for all ARM8.1+ platforms. The previous CAS spinlock implementation had a bug wherein the spin_unlock() implementation had an `sev` after `stlr` which is not sufficient. A dsb is needed to ensure that the stlr completes prior to the sev. Having a dsb is heavyweight and a better solution would be to use load exclusive semantics to monitor the lock and wake up from wfe when a store happens to the lock. The patch implements the same. Change-Id: I5283ce4a889376e4cc01d1b9d09afa8229a2e522 Signed-off-by: Soby Mathew <soby.mathew@arm.com> Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>		2019-10-04 10:19:35 +02:00
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bakery	Switch AARCH32/AARCH64 to __aarch64__	2019-08-01 13:45:03 -07:00
exclusive	Fix the CAS spinlock implementation	2019-10-04 10:19:35 +02:00