linux-toradex.git/include/asm-generic/atomic.h, branch v5.1-rc4

atomics/treewide: Make unconditional inc/dec ops optional

2018-06-21T12:25:24+00:00

Many of the inc/dec ops are mandatory, but for most architectures inc/dec are
simply trivial wrappers around their corresponding add/sub ops.

Let's make all the inc/dec ops optional, so that we can get rid of these
boilerplate wrappers.

The instrumented atomics are updated accordingly.

There should be no functional change as a result of this patch.

Signed-off-by: Mark Rutland 
Reviewed-by: Will Deacon 
Acked-by: Peter Zijlstra (Intel) 
Acked-by: Palmer Dabbelt 
Cc: Boqun Feng 
Cc: Linus Torvalds 
Cc: Thomas Gleixner 
Link: https://lore.kernel.org/lkml/20180621121321.4761-17-mark.rutland@arm.com
Signed-off-by: Ingo Molnar

atomics/treewide: Make test ops optional

2018-06-21T12:25:24+00:00

Some of the atomics return the result of a test applied after the atomic
operation, and almost all architectures implement these as trivial
wrappers around the underlying atomic. Specifically:

 * _inc_and_test(v)    is (_inc_return(v)    == 0)
 * _dec_and_test(v)    is (_dec_return(v)    == 0)
 * _sub_and_test(i, v) is (_sub_return(i, v) == 0)
 * _add_negative(i, v) is (_add_return(i, v)  < 0)

Rather than have these definitions duplicated in all architectures, with
minor inconsistencies in formatting and documentation, let's make these
operations optional, with default fallbacks as above. Implementations
must now provide a preprocessor symbol.

The instrumented atomics are updated accordingly.

Both x86 and m68k have custom implementations, which are left as-is,
given preprocessor symbols to avoid being overridden.

There should be no functional change as a result of this patch.

Signed-off-by: Mark Rutland 
Reviewed-by: Will Deacon 
Acked-by: Geert Uytterhoeven 
Acked-by: Peter Zijlstra (Intel) 
Acked-by: Palmer Dabbelt 
Cc: Boqun Feng 
Cc: Linus Torvalds 
Cc: Thomas Gleixner 
Link: https://lore.kernel.org/lkml/20180621121321.4761-16-mark.rutland@arm.com
Signed-off-by: Ingo Molnar

atomics/treewide: Make atomic_fetch_add_unless() optional

2018-06-21T12:22:33+00:00

Several architectures these have a near-identical implementation based
on atomic_read() and atomic_cmpxchg() which we can instead define in
, so let's do so, using something close to the existing
x86 implementation with try_cmpxchg().

Where an architecture provides its own atomic_fetch_add_unless(), it
must define a preprocessor symbol for it. The instrumented atomics are
updated accordingly.

Note that arch/arc's existing atomic_fetch_add_unless() had redundant
barriers, as these are already present in its atomic_cmpxchg()
implementation.

There should be no functional change as a result of this patch.

Signed-off-by: Mark Rutland 
Reviewed-by: Geert Uytterhoeven 
Reviewed-by: Will Deacon 
Acked-by: Geert Uytterhoeven 
Acked-by: Peter Zijlstra (Intel) 
Acked-by: Palmer Dabbelt 
Cc: Boqun Feng 
Cc: Linus Torvalds 
Cc: Thomas Gleixner 
Cc: Vineet Gupta 
Link: https://lore.kernel.org/lkml/20180621121321.4761-7-mark.rutland@arm.com
Signed-off-by: Ingo Molnar

atomics/treewide: Rename __atomic_add_unless() => atomic_fetch_add_unless()

2018-06-21T12:22:32+00:00

While __atomic_add_unless() was originally intended as a building-block
for atomic_add_unless(), it's now used in a number of places around the
kernel. It's the only common atomic operation named __atomic*(), rather
than atomic_*(), and for consistency it would be better named
atomic_fetch_add_unless().

This lack of consistency is slightly confusing, and gets in the way of
scripting atomics. Given that, let's clean things up and promote it to
an official part of the atomics API, in the form of
atomic_fetch_add_unless().

This patch converts definitions and invocations over to the new name,
including the instrumented version, using the following script:

  ----
  git grep -w __atomic_add_unless | while read line; do
  sed -i '{s/\<__atomic_add_unless\>/atomic_fetch_add_unless/}' "${line%%:*}";
  done
  git grep -w __arch_atomic_add_unless | while read line; do
  sed -i '{s/\<__arch_atomic_add_unless\>/arch_atomic_fetch_add_unless/}' "${line%%:*}";
  done
  ----

Note that we do not have atomic{64,_long}_fetch_add_unless(), which will
be introduced by later patches.

There should be no functional change as a result of this patch.

Signed-off-by: Mark Rutland 
Reviewed-by: Will Deacon 
Acked-by: Geert Uytterhoeven 
Acked-by: Peter Zijlstra (Intel) 
Acked-by: Palmer Dabbelt 
Cc: Boqun Feng 
Cc: Linus Torvalds 
Cc: Thomas Gleixner 
Link: https://lore.kernel.org/lkml/20180621121321.4761-2-mark.rutland@arm.com
Signed-off-by: Ingo Molnar

mn10300: Remove the architecture

2018-03-09T22:19:56+00:00

Remove the MN10300 arch as the hardware is defunct.

Suggested-by: Arnd Bergmann 
Signed-off-by: David Howells 
cc: Masahiro Yamada 
cc: linux-am33-list@redhat.com
Signed-off-by: Arnd Bergmann

openrisc: add optimized atomic operations

2017-02-24T19:14:06+00:00

Using the l.lwa and l.swa atomic instruction pair.
Most openrisc processor cores provide these instructions now. If the
instructions are not available emulation is provided.

Acked-by: Peter Zijlstra (Intel) 
Cc: Peter Zijlstra 
Signed-off-by: Stefan Kristiansson 
[shorne@gmail.com: remove OPENRISC_HAVE_INST_LWA_SWA config suggesed by
Alan Cox https://lkml.org/lkml/2014/7/23/666]
[shorne@gmail.com: expand to implement all ops suggested by Peter
Zijlstra https://lkml.org/lkml/2017/2/20/317]
Signed-off-by: Stafford Horne

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

2016-06-16T08:48:32+00:00

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: Implement atomic{,64,_long}_fetch_{add,sub,and,andnot,or,xor}{,_relaxed,_acquire,_release}()

2016-06-16T08:48:32+00:00

Now that all the architectures have implemented support for these new
atomic primitives add on the generic infrastructure to expose and use
it.

Signed-off-by: Peter Zijlstra (Intel) 
Cc: Andrew Morton 
Cc: Arnd Bergmann 
Cc: Boqun Feng 
Cc: Borislav Petkov 
Cc: Davidlohr Bueso 
Cc: Frederic Weisbecker 
Cc: Linus Torvalds 
Cc: Paul E. McKenney 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: Will Deacon 
Cc: linux-arch@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar

atomic, arch: Audit atomic_{read,set}()

2015-09-23T07:54:28+00:00

This patch makes sure that atomic_{read,set}() are at least
{READ,WRITE}_ONCE().

We already had the 'requirement' that atomic_read() should use
ACCESS_ONCE(), and most archs had this, but a few were lacking.
All are now converted to use READ_ONCE().

And, by a symmetry and general paranoia argument, upgrade atomic_set()
to use WRITE_ONCE().

Signed-off-by: Peter Zijlstra (Intel) 
Cc: Andrew Morton 
Cc: Dmitry Vyukov 
Cc: Linus Torvalds 
Cc: Paul E. McKenney 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: james.hogan@imgtec.com
Cc: linux-kernel@vger.kernel.org
Cc: oleg@redhat.com
Cc: will.deacon@arm.com
Signed-off-by: Ingo Molnar

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