Commit Graph

5 Commits

Author SHA1 Message Date
David Daney
f252ffd50c MIPS: New macro smp_mb__before_llsc.
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 <ddaney@caviumnetworks.com>
To: linux-mips@linux-mips.org
Patchwork: http://patchwork.linux-mips.org/patch/851/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2010-02-27 12:53:06 +01:00
David Daney
b791d1193a MIPS: Allow kernel use of LL/SC to be separate from the presence of LL/SC.
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 <ddaney@caviumnetworks.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2009-09-17 20:07:50 +02:00
Ralf Baechle
47740eb887 MIPS: Enable CLO / CLZ instructions via separate CPU property
This is useful for IDT RC32332, RC32334 and NEC VR5500 processors which do
not implement the full MIPS32 / MIPS64 architecture.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2009-05-14 13:50:26 +01:00
Ralf Baechle
4816227b54 MIPS: Clean up MIPSxx-optimized bitop functions
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-10-30 14:44:33 +00:00
Ralf Baechle
384740dc49 MIPS: Move headfiles to new location below arch/mips/include
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-10-11 16:18:52 +01:00