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Subject[PATCH 10/10] local_t : x86_64 extension
Date
local_t : x86_64 extension

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>

--- a/include/asm-x86_64/local.h
+++ b/include/asm-x86_64/local.h
@@ -2,49 +2,183 @@
#define _ARCH_X8664_LOCAL_H

#include <linux/percpu.h>
+#include <asm/atomic.h>

typedef struct
{
- volatile long counter;
+ atomic_long_t a;
} local_t;

-#define LOCAL_INIT(i) { (i) }
+#define LOCAL_INIT(i) { ATOMIC_LONG_INIT(i) }

-#define local_read(v) ((v)->counter)
-#define local_set(v,i) (((v)->counter) = (i))
+#define local_read(l) atomic_long_read(&(l)->a)
+#define local_set(l,i) atomic_long_set(&(l)->a, (i))

-static inline void local_inc(local_t *v)
+static inline void local_inc(local_t *l)
{
__asm__ __volatile__(
"incq %0"
- :"=m" (v->counter)
- :"m" (v->counter));
+ :"=m" (l->a.counter)
+ :"m" (l->a.counter));
}

-static inline void local_dec(local_t *v)
+static inline void local_dec(local_t *l)
{
__asm__ __volatile__(
"decq %0"
- :"=m" (v->counter)
- :"m" (v->counter));
+ :"=m" (l->a.counter)
+ :"m" (l->a.counter));
}

-static inline void local_add(long i, local_t *v)
+static inline void local_add(long i, local_t *l)
{
__asm__ __volatile__(
"addq %1,%0"
- :"=m" (v->counter)
- :"ir" (i), "m" (v->counter));
+ :"=m" (l->a.counter)
+ :"ir" (i), "m" (l->a.counter));
}

-static inline void local_sub(long i, local_t *v)
+static inline void local_sub(long i, local_t *l)
{
__asm__ __volatile__(
"subq %1,%0"
- :"=m" (v->counter)
- :"ir" (i), "m" (v->counter));
+ :"=m" (l->a.counter)
+ :"ir" (i), "m" (l->a.counter));
}

+/**
+ * local_sub_and_test - subtract value from variable and test result
+ * @i: integer value to subtract
+ * @l: pointer to type local_t
+ *
+ * Atomically subtracts @i from @l and returns
+ * true if the result is zero, or false for all
+ * other cases.
+ */
+static __inline__ int local_sub_and_test(long i, local_t *l)
+{
+ unsigned char c;
+
+ __asm__ __volatile__(
+ "subq %2,%0; sete %1"
+ :"=m" (l->a.counter), "=qm" (c)
+ :"ir" (i), "m" (l->a.counter) : "memory");
+ return c;
+}
+
+/**
+ * local_dec_and_test - decrement and test
+ * @l: pointer to type local_t
+ *
+ * Atomically decrements @l by 1 and
+ * returns true if the result is 0, or false for all other
+ * cases.
+ */
+static __inline__ int local_dec_and_test(local_t *l)
+{
+ unsigned char c;
+
+ __asm__ __volatile__(
+ "decq %0; sete %1"
+ :"=m" (l->a.counter), "=qm" (c)
+ :"m" (l->a.counter) : "memory");
+ return c != 0;
+}
+
+/**
+ * local_inc_and_test - increment and test
+ * @l: pointer to type local_t
+ *
+ * Atomically increments @l by 1
+ * and returns true if the result is zero, or false for all
+ * other cases.
+ */
+static __inline__ int local_inc_and_test(local_t *l)
+{
+ unsigned char c;
+
+ __asm__ __volatile__(
+ "incq %0; sete %1"
+ :"=m" (l->a.counter), "=qm" (c)
+ :"m" (l->a.counter) : "memory");
+ return c != 0;
+}
+
+/**
+ * local_add_negative - add and test if negative
+ * @i: integer value to add
+ * @l: pointer to type local_t
+ *
+ * Atomically adds @i to @l and returns true
+ * if the result is negative, or false when
+ * result is greater than or equal to zero.
+ */
+static __inline__ int local_add_negative(long i, local_t *l)
+{
+ unsigned char c;
+
+ __asm__ __volatile__(
+ "addq %2,%0; sets %1"
+ :"=m" (l->a.counter), "=qm" (c)
+ :"ir" (i), "m" (l->a.counter) : "memory");
+ return c;
+}
+
+/**
+ * local_add_return - add and return
+ * @i: integer value to add
+ * @l: pointer to type local_t
+ *
+ * Atomically adds @i to @l and returns @i + @l
+ */
+static __inline__ long local_add_return(long i, local_t *l)
+{
+ long __i = i;
+ __asm__ __volatile__(
+ "xaddq %0, %1;"
+ :"+r" (i), "+m" (l->a.counter)
+ : : "memory");
+ return i + __i;
+}
+
+static __inline__ long local_sub_return(long i, local_t *l)
+{
+ return local_add_return(-i,l);
+}
+
+#define local_inc_return(l) (local_add_return(1,l))
+#define local_dec_return(l) (local_sub_return(1,l))
+
+#define local_cmpxchg(l, o, n) \
+ ((long)cmpxchg_local(&((l)->a.counter), (o), (n)))
+/* Always has a lock prefix anyway */
+#define local_xchg(l, new) (xchg(&((l)->a.counter), new))
+
+/**
+ * atomic_up_add_unless - add unless the number is a given value
+ * @l: pointer of type local_t
+ * @a: the amount to add to l...
+ * @u: ...unless l 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.
+ */
+#define local_add_unless(l, a, u) \
+({ \
+ long c, old; \
+ c = local_read(l); \
+ for (;;) { \
+ if (unlikely(c == (u))) \
+ break; \
+ old = local_cmpxchg((l), c, c + (a)); \
+ if (likely(old == c)) \
+ break; \
+ c = old; \
+ } \
+ c != (u); \
+})
+#define local_inc_not_zero(l) local_add_unless((l), 1, 0)
+
/* On x86-64 these are better than the atomic variants on SMP kernels
because they dont use a lock prefix. */
#define __local_inc(l) local_inc(l)
@@ -62,27 +196,27 @@ static inline void local_sub(long i, local_t *v)

/* 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(v) \
+#define cpu_local_wrap_v(l) \
({ local_t res__; \
preempt_disable(); \
- res__ = (v); \
+ res__ = (l); \
preempt_enable(); \
res__; })
-#define cpu_local_wrap(v) \
+#define cpu_local_wrap(l) \
({ preempt_disable(); \
- v; \
+ l; \
preempt_enable(); }) \

-#define cpu_local_read(v) cpu_local_wrap_v(local_read(&__get_cpu_var(v)))
-#define cpu_local_set(v, i) cpu_local_wrap(local_set(&__get_cpu_var(v), (i)))
-#define cpu_local_inc(v) cpu_local_wrap(local_inc(&__get_cpu_var(v)))
-#define cpu_local_dec(v) cpu_local_wrap(local_dec(&__get_cpu_var(v)))
-#define cpu_local_add(i, v) cpu_local_wrap(local_add((i), &__get_cpu_var(v)))
-#define cpu_local_sub(i, v) cpu_local_wrap(local_sub((i), &__get_cpu_var(v)))
+#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(v) cpu_local_inc(v)
-#define __cpu_local_dec(v) cpu_local_dec(v)
-#define __cpu_local_add(i, v) cpu_local_add((i), (v))
-#define __cpu_local_sub(i, v) cpu_local_sub((i), (v))
+#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_I386_LOCAL_H */
+#endif /* _ARCH_X8664_LOCAL_H */
--- a/include/asm-x86_64/system.h
+++ b/include/asm-x86_64/system.h
@@ -209,9 +209,45 @@ static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old,
return old;
}

+static inline unsigned long __cmpxchg_local(volatile void *ptr,
+ unsigned long old, unsigned long new, int size)
+{
+ unsigned long prev;
+ switch (size) {
+ case 1:
+ __asm__ __volatile__("cmpxchgb %b1,%2"
+ : "=a"(prev)
+ : "q"(new), "m"(*__xg(ptr)), "0"(old)
+ : "memory");
+ return prev;
+ case 2:
+ __asm__ __volatile__("cmpxchgw %w1,%2"
+ : "=a"(prev)
+ : "r"(new), "m"(*__xg(ptr)), "0"(old)
+ : "memory");
+ return prev;
+ case 4:
+ __asm__ __volatile__("cmpxchgl %k1,%2"
+ : "=a"(prev)
+ : "r"(new), "m"(*__xg(ptr)), "0"(old)
+ : "memory");
+ return prev;
+ case 8:
+ __asm__ __volatile__("cmpxchgq %1,%2"
+ : "=a"(prev)
+ : "r"(new), "m"(*__xg(ptr)), "0"(old)
+ : "memory");
+ return prev;
+ }
+ return old;
+}
+
#define cmpxchg(ptr,o,n)\
((__typeof__(*(ptr)))__cmpxchg((ptr),(unsigned long)(o),\
(unsigned long)(n),sizeof(*(ptr))))
+#define cmpxchg_local(ptr,o,n)\
+ ((__typeof__(*(ptr)))__cmpxchg((ptr),(unsigned long)(o),\
+ (unsigned long)(n),sizeof(*(ptr))))

#ifdef CONFIG_SMP
#define smp_mb() mb()
-
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