lwn.git/arch/powerpc/include/asm/atomic.h, branch v4.7.8

powerpc: atomic: Implement acquire/release/relaxed variants for cmpxchg

2016-02-17T13:11:39+00:00

Implement cmpxchg{,64}_relaxed and atomic{,64}_cmpxchg_relaxed, based on which _release variants can be built. To avoid superfluous barriers in _acquire variants, we implement these operations with assembly code rather use __atomic_op_acquire() to build them automatically. For the same reason, we keep the assembly implementation of fully ordered cmpxchg operations. However, we don't do the similar for _release, because that will require putting barriers in the middle of ll/sc loops, which is probably a bad idea. Note cmpxchg{,64}_relaxed and atomic{,64}_cmpxchg_relaxed are not compiler barriers. Signed-off-by: Boqun Feng Signed-off-by: Michael Ellerman

powerpc: atomic: Implement acquire/release/relaxed variants for xchg

2016-02-17T13:11:31+00:00

Implement xchg{,64}_relaxed and atomic{,64}_xchg_relaxed, based on these _relaxed variants, release/acquire variants and fully ordered versions can be built. Note that xchg{,64}_relaxed and atomic_{,64}_xchg_relaxed are not compiler barriers. Signed-off-by: Boqun Feng Signed-off-by: Michael Ellerman

powerpc: atomic: Implement atomic{, 64}__return_ variants

2016-02-17T13:11:21+00:00

On powerpc, acquire and release semantics can be achieved with lightweight barriers("lwsync" and "ctrl+isync"), which can be used to implement __atomic_op_{acquire,release}. For release semantics, since we only need to ensure all memory accesses that issue before must take effects before the -store- part of the atomics, "lwsync" is what we only need. On the platform without "lwsync", "sync" should be used. Therefore in __atomic_op_release() we use PPC_RELEASE_BARRIER. For acquire semantics, "lwsync" is what we only need for the similar reason. However on the platform without "lwsync", we can use "isync" rather than "sync" as an acquire barrier. Therefore in __atomic_op_acquire() we use PPC_ACQUIRE_BARRIER, which is barrier() on UP, "lwsync" if available and "isync" otherwise. Implement atomic{,64}_{add,sub,inc,dec}_return_relaxed, and build other variants with these helpers. Signed-off-by: Boqun Feng Signed-off-by: Michael Ellerman

atomic: Provide atomic_{or,xor,and}

2015-07-27T12:06:24+00:00

Implement atomic logic ops -- atomic_{or,xor,and}. These will replace the atomic_{set,clear}_mask functions that are available on some archs. Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Thomas Gleixner

powerpc: Provide atomic_{or,xor,and}

2015-07-27T12:06:23+00:00

Implement atomic logic ops -- atomic_{or,xor,and}. These will replace the atomic_{set,clear}_mask functions that are available on some archs. Acked-by: Benjamin Herrenschmidt Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Thomas Gleixner

locking,arch,powerpc: Fold atomic_ops

2014-08-14T10:48:11+00:00

Many of the atomic op implementations are the same except for one instruction; fold the lot into a few CPP macros and reduce LoC. Requires asm_op because PPC asm is weird :-) Signed-off-by: Peter Zijlstra Cc: Benjamin Herrenschmidt Cc: Linus Torvalds Cc: Paul E. McKenney Cc: Paul Mackerras Cc: Mahesh Salgaonkar Cc: Paul Gortmaker Cc: linuxppc-dev@lists.ozlabs.org Link: http://lkml.kernel.org/r/20140508135852.713980957@infradead.org Signed-off-by: Ingo Molnar

arch,powerpc: Convert smp_mb__*()

2014-04-18T12:20:41+00:00

Powerpc allows reordering over its ll/sc implementation. Implement the two new barriers as appropriate. Signed-off-by: Peter Zijlstra Acked-by: Paul E. McKenney Link: http://lkml.kernel.org/n/tip-gg2ffgq32sjgy9b8lj6m3hsc@git.kernel.org Cc: Benjamin Herrenschmidt Cc: Linus Torvalds Cc: Mahesh Salgaonkar Cc: Paul Gortmaker Cc: Paul Mackerras Cc: Will Deacon Cc: linux-kernel@vger.kernel.org Cc: linuxppc-dev@lists.ozlabs.org Signed-off-by: Ingo Molnar

atomic: implement generic atomic_dec_if_positive()

2012-10-09T07:22:46+00:00

The x86 implementation of atomic_dec_if_positive is quite generic, so make it available to all architectures. This is needed for "swap: add a simple detector for inappropriate swapin readahead". [akpm@linux-foundation.org: do the "#define foo foo" trick in the conventional manner] Signed-off-by: Shaohua Li Cc: Stephen Rothwell Cc: "David S. Miller" Cc: Rik van Riel Cc: Ingo Molnar Cc: Thomas Gleixner Cc: "H. Peter Anvin" Cc: Benjamin Herrenschmidt Cc: Michal Simek Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Disintegrate asm/system.h for PowerPC

2012-03-28T17:30:02+00:00

Disintegrate asm/system.h for PowerPC. Signed-off-by: David Howells Acked-by: Benjamin Herrenschmidt cc: linuxppc-dev@lists.ozlabs.org

powerpc/atomic: Implement atomic*_inc_not_zero

2012-03-07T06:06:08+00:00

Implement atomic_inc_not_zero and atomic64_inc_not_zero. At the moment we use atomic*_add_unless which requires us to put 0 and 1 constants into registers. We can also avoid a subtract by saving the original value in a second temporary. This removes 3 instructions from fget: - c0000000001b63c0: 39 00 00 00 li r8,0 - c0000000001b63c4: 39 40 00 01 li r10,1 ... - c0000000001b63e8: 7c 0a 00 50 subf r0,r10,r0 Signed-off-by: Anton Blanchard Signed-off-by: Benjamin Herrenschmidt