kernel/arch/csky/include/asm/spinlock.h, branch linux-rolling-stable

csky: Add qspinlock support

2022-07-31T09:24:42Z

Enable qspinlock by the requirements mentioned in a8ad07e5240c9 ("asm-generic: qspinlock: Indicate the use of mixed-size atomics"). C-SKY only has "ldex/stex" for all atomic operations. So csky give a strong forward guarantee for "ldex/stex." That means when ldex grabbed the cache line into $L1, it would block other cores from snooping the address with several cycles. The atomic_fetch_add & xchg16 has the same forward guarantee level in C-SKY. Qspinlock has better code size and performance in a fast path. Signed-off-by: Guo Ren Signed-off-by: Guo Ren

csky: Move to generic ticket-spinlock

2022-05-11T18:50:15Z

There is no benefit from custom implementation for ticket-spinlock, so move to generic ticket-spinlock for easy maintenance. Signed-off-by: Guo Ren Reviewed-by: Arnd Bergmann Signed-off-by: Palmer Dabbelt

csky: Cleanup asm/spinlock.h

2021-01-12T01:52:40Z

There are two implementation of spinlock in arch/csky: - simple one (NR_CPU = 1,2) - tick's one (NR_CPU = 3,4) Remove the simple one. There is already smp_mb in spinlock, so remove the definition of smp_mb__after_spinlock. Link: https://lore.kernel.org/linux-csky/20200807081253.GD2674@hirez.programming.kicks-ass.net/#t Signed-off-by: Guo Ren Cc: Peter Zijlstra k Cc: Arnd Bergmann

csky: Atomic operations

2018-10-25T16:54:23Z

This patch adds atomic, cmpxchg, spinlock files. Signed-off-by: Guo Ren Cc: Andrea Parri Cc: Arnd Bergmann Reviewed-by: Peter Zijlstra