kernel/arch/arc/include/asm/atomic.h, branch linux-4.15.y

locking/atomic: Fix atomic_set_release() for 'funny' architectures

2017-08-10T10:28:54Z

Those architectures that have a special atomic_set implementation also need a special atomic_set_release(), because for the very same reason WRITE_ONCE() is broken for them, smp_store_release() is too. The vast majority is architectures that have spinlock hash based atomic implementation except hexagon which seems to have a hardware 'feature'. The spinlock based atomics should be SC, that is, none of them appear to place extra barriers in atomic_cmpxchg() or any of the other SC atomic primitives and therefore seem to rely on their spinlock implementation being SC (I did not fully validate all that). Therefore, the normal atomic_set() is SC and can be used at atomic_set_release(). Signed-off-by: Peter Zijlstra (Intel) Acked-by: Chris Metcalf [for tile] Cc: Boqun Feng Cc: Linus Torvalds Cc: Paul McKenney Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Will Deacon Cc: davem@davemloft.net Cc: james.hogan@imgtec.com Cc: jejb@parisc-linux.org Cc: rkuo@codeaurora.org Cc: vgupta@synopsys.com Link: http://lkml.kernel.org/r/20170609110506.yod47flaav3wgoj5@hirez.programming.kicks-ass.net Signed-off-by: Ingo Molnar

ARC: [plat-eznps] Fix build error

2017-04-14T16:56:06Z

Make ATOMIC_INIT available for all ARC platforms (including plat-eznps) Cc: # 4.9+ Signed-off-by: Noam Camus Signed-off-by: Vineet Gupta

ARC: [plat-eznps] add missing atomic_fetch_xxx operations

2016-09-30T21:48:18Z

Build brekeage since last changes to generic atomic operations. Added couple of missing macros which are now mandatory Signed-off-by: Noam Camus Signed-off-by: Vineet Gupta

ARCv2: Implement atomic64 based on LLOCKD/SCONDD instructions

2016-09-30T21:48:17Z

ARCv2 ISA provides 64-bit exclusive load/stores so use them to implement the 64-bit atomics and elide the spinlock based generic 64-bit atomics boot tested with atomic64 self-test (and GOD bless the person who wrote them, I realized my inline assmebly is sloppy as hell) Cc: Peter Zijlstra Cc: Will Deacon Cc: linux-snps-arc@lists.infradead.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Vineet Gupta

locking/atomic, arch/arc: Fix build

2016-06-20T09:25:49Z

Resolve conflict between commits: fbffe892e525 ("locking/atomic, arch/arc: Implement atomic_fetch_{add,sub,and,andnot,or,xor}()") and: ed6aefed726a ("Revert "ARCv2: spinlock/rwlock/atomics: Delayed retry of failed SCOND with exponential backoff"") Reported-by: Guenter Roeck Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Nigel Topham Cc: Noam Camus Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Vineet Gupta Cc: linux-kernel@vger.kernel.org Cc: linux-snps-arc@lists.infradead.org Signed-off-by: Ingo Molnar

locking/atomic: Remove linux/atomic.h:atomic_fetch_or()

2016-06-16T08:48:32Z

Since all architectures have this implemented now natively, remove this dead code. Signed-off-by: Peter Zijlstra (Intel) Cc: Andrew Morton Cc: Linus Torvalds Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-arch@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar

locking/atomic, arch/arc: Implement atomic_fetch_{add,sub,and,andnot,or,xor}()

2016-06-16T08:48:20Z

Implement FETCH-OP atomic primitives, these are very similar to the existing OP-RETURN primitives we already have, except they return the value of the atomic variable _before_ modification. This is especially useful for irreversible operations -- such as bitops (because it becomes impossible to reconstruct the state prior to modification). Signed-off-by: Peter Zijlstra (Intel) Acked-by: Vineet Gupta Cc: Andrew Morton Cc: Linus Torvalds Cc: Noam Camus Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-arch@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: linux-snps-arc@lists.infradead.org Signed-off-by: Ingo Molnar

Revert "ARCv2: spinlock/rwlock/atomics: Delayed retry of failed SCOND with exponential backoff"

2016-06-02T05:29:23Z

This reverts commit e78fdfef84be13a5c2b8276e12203cdf24778596. The issue was fixed in hardware in HS2.1C release and there are no known external users of affected RTL so revert the whole delayed retry series ! Signed-off-by: Vineet Gupta

Revert "ARCv2: spinlock/rwlock/atomics: reduce 1 instruction in exponential backoff"

2016-06-02T05:29:22Z

This reverts commit 10971638701dedadb58c88ce4d31c9375b224ed6. The issue was fixed in hardware in HS2.1C release and there are no known external users of affected RTL - so revert thw whole delayed retry series ! Signed-off-by: Vineet Gupta

ARC: [plat-eznps] Use dedicated atomic/bitops/cmpxchg

2016-05-09T04:02:33Z

We need our own implementaions since we lack LLSC support. Our extended ISA provided with optimized solution for all 32bit operations we see in these three headers. Signed-off-by: Noam Camus