linux-toradex.git/arch/mips/include/asm/atomic.h, branch v3.3.5

atomic: cleanup asm-generic atomic*.h inclusion

2011-07-26T23:49:47+00:00

After changing all consumers of atomics to include , we
ran into some compile time errors due to this dependency chain:

linux/atomic.h
  -> asm/atomic.h
    -> asm-generic/atomic-long.h

where atomic-long.h could use funcs defined later in linux/atomic.h
without a prototype.  This patches moves the code that includes
asm-generic/atomic*.h to linux/atomic.h.

Archs that need  need to select
CONFIG_GENERIC_ATOMIC64 from now on (some of them used to include it
unconditionally).

Compile tested on i386 and x86_64 with allnoconfig.

Signed-off-by: Arun Sharma 
Cc: Eric Dumazet 
Cc: Ingo Molnar 
Cc: David Miller 
Acked-by: Mike Frysinger 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

atomic: move atomic_add_unless to generic code

2011-07-26T23:49:47+00:00

This is in preparation for more generic atomic primitives based on
__atomic_add_unless.

Signed-off-by: Arun Sharma 
Signed-off-by: Hans-Christian Egtvedt 
Reviewed-by: Eric Dumazet 
Cc: Ingo Molnar 
Cc: David Miller 
Acked-by: Mike Frysinger 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

atomic: use

2011-07-26T23:49:47+00:00

This allows us to move duplicated code in 
(atomic_inc_not_zero() for now) to 

Signed-off-by: Arun Sharma 
Reviewed-by: Eric Dumazet 
Cc: Ingo Molnar 
Cc: David Miller 
Cc: Eric Dumazet 
Acked-by: Mike Frysinger 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

MIPS: Get rid of branches to .subsections.

2010-10-29T18:08:24+00:00

It was a nice optimization - on paper at least.  In practice it results in
branches that may exceed the maximum legal range for a branch.  We can
fight that problem with -ffunction-sections but -ffunction-sections again
is incompatible with -pg used by the function tracer.

By rewriting the loop around all simple LL/SC blocks to C we reduce the
amount of inline assembler and at the same time allow GCC to often fill
the branch delay slots with something sensible or whatever else clever
optimization it may have up in its sleeve.

With this optimization gone we also no longer need -ffunction-sections,
so drop it.

This optimization was originally introduced in 2.6.21, commit
5999eca25c1fd4b9b9aca7833b04d10fe4bc877d (linux-mips.org) rsp.
f65e4fa8e0c6022ad58dc88d1b11b12589ed7f9f (kernel.org).

Original fix for the issues which caused me to pull this optimization by
Paul Gortmaker .

Signed-off-by: Ralf Baechle

MIPS: Use generic atomic64 for 32-bit kernels

2010-10-04T17:33:54+00:00

The 64-bit kernel has already had its atomic64 functions. Except for that,
we use the generic spinlocked version. The atomic64 types and related
functions are needed for the Linux performance counter subsystem.

Signed-off-by: Deng-Cheng Zhu 
To: linux-mips@linux-mips.org
Cc: a.p.zijlstra@chello.nl
Cc: paulus@samba.org
Cc: mingo@elte.hu
Cc: acme@redhat.com
Cc: jamie.iles@picochip.com
Patchwork: https://patchwork.linux-mips.org/patch/1361/
Acked-by: David Daney 
Signed-off-by: Ralf Baechle

MIPS: Quit using undefined behavior of ADDU in 64-bit atomic operations.

2010-07-26T18:08:18+00:00

For 64-bit, we must use DADDU and DSUBU.

Signed-off-by: David Daney 
To: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/1483/
Signed-off-by: Ralf Baechle

atomic_t: Cast to volatile when accessing atomic variables

2010-05-17T14:57:27+00:00

In preparation for removing volatile from the atomic_t definition, this
patch adds a volatile cast to all the atomic read functions.

Signed-off-by: Anton Blanchard 
Signed-off-by: Linus Torvalds

MIPS: New macro smp_mb__before_llsc.

2010-02-27T11:53:06+00:00

Replace some instances of smp_llsc_mb() with a new macro
smp_mb__before_llsc().  It is used before ll/sc sequences that are
documented as needing write barrier semantics.

The default implementation of smp_mb__before_llsc() is just smp_llsc_mb(),
so there are no changes in semantics.

Also simplify definition of smp_mb(), smp_rmb(), and smp_wmb() to be just
barrier() in the non-SMP case.

Signed-off-by: David Daney 
To: linux-mips@linux-mips.org
Patchwork: http://patchwork.linux-mips.org/patch/851/
Signed-off-by: Ralf Baechle

MIPS: Allow kernel use of LL/SC to be separate from the presence of LL/SC.

2009-09-17T18:07:50+00:00

On some CPUs, it is more efficient to disable and enable interrupts in the
kernel rather than use ll/sc for atomic operations.  But if we were to set
cpu_has_llsc to false, we would break the userspace futex interface (in
asm/futex.h).

We separate the two concepts, with a new predicate kernel_uses_llsc, that
lets us disable the kernel's use of ll/sc while still allowing the futex
code to use it.

Also there were a couple of cases in bitops.h where we were using ll/sc
unconditionally even if cpu_has_llsc were false.

Signed-off-by: David Daney 
Signed-off-by: Ralf Baechle

asm-generic: rename atomic.h to atomic-long.h

2009-06-11T19:02:17+00:00

The existing asm-generic/atomic.h only defines the
atomic_long type. This renames it to atomic-long.h
so we have a place to add a truly generic atomic.h
that can be used on all non-SMP systems.

Signed-off-by: Remis Lima Baima 
Signed-off-by: Arnd Bergmann 
Acked-by: Ingo Molnar