BMC/Intel-BMC/linux.git/arch/s390/include/asm/atomic.h, branch dev-4.6

s390/barrier: remove unnecessary serialization in atomics and bitops

2015-10-14T12:32:07+00:00

The principles of operation states reads are in order, writes are in order, writes can be reordered after reads, but no reads can be reordered after writes. The atomic and bitops variantes for z196 use the interlocked-access facility instructions with a memory barrier before and after the instruction. Because of the memory ordering the first barrier is unnecessary and can be removed. Acked-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

atomic: Collapse all atomic_{set,clear}_mask definitions

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

Move the now generic definitions of atomic_{set,clear}_mask() into linux/atomic.h to avoid endless and pointless repetition. Also, provide an atomic_andnot() wrapper for those few archs that can implement that. Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Thomas Gleixner

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

s390: 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: Heiko Carstens Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Thomas Gleixner

s390: remove 31 bit support

2015-03-25T10:49:33+00:00

Remove the 31 bit support in order to reduce maintenance cost and effectively remove dead code. Since a couple of years there is no distribution left that comes with a 31 bit kernel. The 31 bit kernel also has been broken since more than a year before anybody noticed. In addition I added a removal warning to the kernel shown at ipl for 5 minutes: a960062e5826 ("s390: add 31 bit warning message") which let everybody know about the plan to remove 31 bit code. We didn't get any response. Given that the last 31 bit only machine was introduced in 1999 let's remove the code. Anybody with 31 bit user space code can still use the compat mode. Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

arch,s390: Convert smp_mb__*()

2014-04-18T12:20:42+00:00

As per the existing implementation; implement the new one using smp_mb(). AFAICT the s390 compare-and-swap does imply a barrier, however there are some immediate ops that seem to be singly-copy atomic and do not imply a barrier. One such is the "ni" op (which would be and-immediate) which is used for the constant clear_bit implementation. Therefore s390 needs full barriers for the {before,after} atomic ops. Signed-off-by: Peter Zijlstra Acked-by: Paul E. McKenney Link: http://lkml.kernel.org/n/tip-kme5dz5hcobpnufnnkh1ech2@git.kernel.org Cc: Chen Gang Cc: Heiko Carstens Cc: Linus Torvalds Cc: Martin Schwidefsky Cc: Will Deacon Cc: linux390@de.ibm.com Cc: linux-kernel@vger.kernel.org Cc: linux-s390@vger.kernel.org Signed-off-by: Ingo Molnar

s390/bitops,atomic: add missing memory barriers

2014-04-01T07:23:35+00:00

When reworking the bitops and atomic ops I missed that those instructions that got atomic behaviour only perform a "specific-operand-serialization" instead of a full "serialization". The compare-and-swap instruction used before performs a full serialization before and after the instruction is executed, which means it has full memory barrier semantics. In order to give the new bitops and atomic ops functions also full memory barrier semantics add a "bcr 14,0" before and after each of those new instructions which performs full serialization as well. This restores memory barrier semantics for bitops and atomic ops functions which return values, like e.g. atomic_add_return(), but not for functions which do not return a value, like e.g. atomic_add(). This is consistent to other architectures and what common code requires. Cc: stable@vger.kernel.org # v3.13+ Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

s390/atomic: use 'unsigned int' instead of 'unsigned long' for atomic_*_mask()

2013-10-24T15:17:02+00:00

The type of 'v->counter' is always 'int', and related inline assembly code also process 'int', so use 'unsigned int' instead of 'unsigned long' for the 'mask'. Signed-off-by: Chen Gang Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

s390/atomic: various small cleanups

2013-10-24T15:16:51+00:00

- add a typecheck to the defines to make sure they operate on an atomic_t - simplify inline assembly constraints - keep variable names common between functions Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

s390/atomic: optimize atomic_add() for constant values

2013-10-24T15:16:51+00:00

If the interlocked-access facility 1 is available we can use the asi and agsi instructions for interlocked updates if the to be added value is a contanst and small (in the range of -128..127). asi and agsi do not not return the old or new value, therefore these instructions can only be used for atomic_(add|sub|inc|dec)[64]. Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky