local_t: powerpc extension

[akpm@linux-foundation.org: build fixes]
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 200 insertions, 1 deletions

diff --git a/include/asm-powerpc/local.h b/include/asm-powerpc/local.h
index c11c530f74d0..612d83276653 100644
--- a/include/asm-powerpc/local.h
+++ b/include/asm-powerpc/local.h
@@ -1 +1,200 @@
-#include <asm-generic/local.h>
+#ifndef _ARCH_POWERPC_LOCAL_H
+#define _ARCH_POWERPC_LOCAL_H
+
+#include <linux/percpu.h>
+#include <asm/atomic.h>
+
+typedef struct
+{
+        atomic_long_t a;
+} local_t;
+
+#define LOCAL_INIT(i)   { ATOMIC_LONG_INIT(i) }
+
+#define local_read(l)   atomic_long_read(&(l)->a)
+#define local_set(l,i)  atomic_long_set(&(l)->a, (i))
+
+#define local_add(i,l)  atomic_long_add((i),(&(l)->a))
+#define local_sub(i,l)  atomic_long_sub((i),(&(l)->a))
+#define local_inc(l)    atomic_long_inc(&(l)->a)
+#define local_dec(l)    atomic_long_dec(&(l)->a)
+
+static __inline__ long local_add_return(long a, local_t *l)
+{
+        long t;
+
+        __asm__ __volatile__(
+"1:"    PPC_LLARX       "%0,0,%2                # local_add_return\n\
+        add     %0,%1,%0\n"
+        PPC405_ERR77(0,%2)
+        PPC_STLCX       "%0,0,%2 \n\
+        bne-    1b"
+        : "=&r" (t)
+        : "r" (a), "r" (&(l->a.counter))
+        : "cc", "memory");
+
+        return t;
+}
+
+#define local_add_negative(a, l)        (local_add_return((a), (l)) < 0)
+
+static __inline__ long local_sub_return(long a, local_t *l)
+{
+        long t;
+
+        __asm__ __volatile__(
+"1:"    PPC_LLARX       "%0,0,%2                # local_sub_return\n\
+        subf    %0,%1,%0\n"
+        PPC405_ERR77(0,%2)
+        PPC_STLCX       "%0,0,%2 \n\
+        bne-    1b"
+        : "=&r" (t)
+        : "r" (a), "r" (&(l->a.counter))
+        : "cc", "memory");
+
+        return t;
+}
+
+static __inline__ long local_inc_return(local_t *l)
+{
+        long t;
+
+        __asm__ __volatile__(
+"1:"    PPC_LLARX       "%0,0,%1                # local_inc_return\n\
+        addic   %0,%0,1\n"
+        PPC405_ERR77(0,%1)
+        PPC_STLCX       "%0,0,%1 \n\
+        bne-    1b"
+        : "=&r" (t)
+        : "r" (&(l->a.counter))
+        : "cc", "memory");
+
+        return t;
+}
+
+/*
+ * local_inc_and_test - increment and test
+ * @l: pointer of type local_t
+ *
+ * Atomically increments @l by 1
+ * and returns true if the result is zero, or false for all
+ * other cases.
+ */
+#define local_inc_and_test(l) (local_inc_return(l) == 0)
+
+static __inline__ long local_dec_return(local_t *l)
+{
+        long t;
+
+        __asm__ __volatile__(
+"1:"    PPC_LLARX       "%0,0,%1                # local_dec_return\n\
+        addic   %0,%0,-1\n"
+        PPC405_ERR77(0,%1)
+        PPC_STLCX       "%0,0,%1\n\
+        bne-    1b"
+        : "=&r" (t)
+        : "r" (&(l->a.counter))
+        : "cc", "memory");
+
+        return t;
+}
+
+#define local_cmpxchg(l, o, n) \
+        (cmpxchg_local(&((l)->a.counter), (o), (n)))
+#define local_xchg(l, n) (xchg_local(&((l)->a.counter), (n)))
+
+/**
+ * local_add_unless - add unless the number is a given value
+ * @l: pointer of type local_t
+ * @a: the amount to add to v...
+ * @u: ...unless v is equal to u.
+ *
+ * Atomically adds @a to @l, so long as it was not @u.
+ * Returns non-zero if @l was not @u, and zero otherwise.
+ */
+static __inline__ int local_add_unless(local_t *l, long a, long u)
+{
+        long t;
+
+        __asm__ __volatile__ (
+"1:"    PPC_LLARX       "%0,0,%1                # local_add_unless\n\
+        cmpw    0,%0,%3 \n\
+        beq-    2f \n\
+        add     %0,%2,%0 \n"
+        PPC405_ERR77(0,%2)
+        PPC_STLCX       "%0,0,%1 \n\
+        bne-    1b \n"
+"       subf    %0,%2,%0 \n\
+2:"
+        : "=&r" (t)
+        : "r" (&(l->a.counter)), "r" (a), "r" (u)
+        : "cc", "memory");
+
+        return t != u;
+}
+
+#define local_inc_not_zero(l) local_add_unless((l), 1, 0)
+
+#define local_sub_and_test(a, l)        (local_sub_return((a), (l)) == 0)
+#define local_dec_and_test(l)           (local_dec_return((l)) == 0)
+
+/*
+ * Atomically test *l and decrement if it is greater than 0.
+ * The function returns the old value of *l minus 1.
+ */
+static __inline__ long local_dec_if_positive(local_t *l)
+{
+        long t;
+
+        __asm__ __volatile__(
+"1:"    PPC_LLARX       "%0,0,%1                # local_dec_if_positive\n\
+        cmpwi   %0,1\n\
+        addi    %0,%0,-1\n\
+        blt-    2f\n"
+        PPC405_ERR77(0,%1)
+        PPC_STLCX       "%0,0,%1\n\
+        bne-    1b"
+        "\n\
+2:"     : "=&b" (t)
+        : "r" (&(l->a.counter))
+        : "cc", "memory");
+
+        return t;
+}
+
+/* Use these for per-cpu local_t variables: on some archs they are
+ * much more efficient than these naive implementations.  Note they take
+ * a variable, not an address.
+ */
+
+#define __local_inc(l)          ((l)->a.counter++)
+#define __local_dec(l)          ((l)->a.counter++)
+#define __local_add(i,l)        ((l)->a.counter+=(i))
+#define __local_sub(i,l)        ((l)->a.counter-=(i))
+
+/* Need to disable preemption for the cpu local counters otherwise we could
+   still access a variable of a previous CPU in a non atomic way. */
+#define cpu_local_wrap_v(l)             \
+        ({ local_t res__;               \
+           preempt_disable();           \
+           res__ = (l);                 \
+           preempt_enable();            \
+           res__; })
+#define cpu_local_wrap(l)               \
+        ({ preempt_disable();           \
+           l;                           \
+           preempt_enable(); })         \
+
+#define cpu_local_read(l)    cpu_local_wrap_v(local_read(&__get_cpu_var(l)))
+#define cpu_local_set(l, i)  cpu_local_wrap(local_set(&__get_cpu_var(l), (i)))
+#define cpu_local_inc(l)     cpu_local_wrap(local_inc(&__get_cpu_var(l)))
+#define cpu_local_dec(l)     cpu_local_wrap(local_dec(&__get_cpu_var(l)))
+#define cpu_local_add(i, l)  cpu_local_wrap(local_add((i), &__get_cpu_var(l)))
+#define cpu_local_sub(i, l)  cpu_local_wrap(local_sub((i), &__get_cpu_var(l)))
+
+#define __cpu_local_inc(l)      cpu_local_inc(l)
+#define __cpu_local_dec(l)      cpu_local_dec(l)
+#define __cpu_local_add(i, l)   cpu_local_add((i), (l))
+#define __cpu_local_sub(i, l)   cpu_local_sub((i), (l))
+
+#endif /* _ARCH_POWERPC_LOCAL_H */