--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/arch/x86/include/asm/local.h Sun Jan 11 20:20:11 2009 +0100
@@ -0,0 +1,235 @@
+#ifndef _ASM_X86_LOCAL_H
+#define _ASM_X86_LOCAL_H
+
+#include <linux/percpu.h>
+
+#include <asm/system.h>
+#include <asm/atomic.h>
+#include <asm/asm.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))
+
+static inline void local_inc(local_t *l)
+{
+ asm volatile(_ASM_INC "%0"
+ : "+m" (l->a.counter));
+}
+
+static inline void local_dec(local_t *l)
+{
+ asm volatile(_ASM_DEC "%0"
+ : "+m" (l->a.counter));
+}
+
+static inline void local_add(long i, local_t *l)
+{
+ asm volatile(_ASM_ADD "%1,%0"
+ : "+m" (l->a.counter)
+ : "ir" (i));
+}
+
+static inline void local_sub(long i, local_t *l)
+{
+ asm volatile(_ASM_SUB "%1,%0"
+ : "+m" (l->a.counter)
+ : "ir" (i));
+}
+
+/**
+ * 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(_ASM_SUB "%2,%0; sete %1"
+ : "+m" (l->a.counter), "=qm" (c)
+ : "ir" (i) : "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(_ASM_DEC "%0; sete %1"
+ : "+m" (l->a.counter), "=qm" (c)
+ : : "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(_ASM_INC "%0; sete %1"
+ : "+m" (l->a.counter), "=qm" (c)
+ : : "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(_ASM_ADD "%2,%0; sets %1"
+ : "+m" (l->a.counter), "=qm" (c)
+ : "ir" (i) : "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;
+#ifdef CONFIG_M386
+ unsigned long flags;
+ if (unlikely(boot_cpu_data.x86 <= 3))
+ goto no_xadd;
+#endif
+ /* Modern 486+ processor */
+ __i = i;
+ asm volatile(_ASM_XADD "%0, %1;"
+ : "+r" (i), "+m" (l->a.counter)
+ : : "memory");
+ return i + __i;
+
+#ifdef CONFIG_M386
+no_xadd: /* Legacy 386 processor */
+ local_irq_save(flags);
+ __i = local_read(l);
+ local_set(l, i + __i);
+ local_irq_restore(flags);
+ return i + __i;
+#endif
+}
+
+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) \
+ (cmpxchg_local(&((l)->a.counter), (o), (n)))
+/* Always has a lock prefix */
+#define local_xchg(l, n) (xchg(&((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 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_32, these are no better than the atomic variants.
+ * 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)
+#define __local_dec(l) local_dec(l)
+#define __local_add(i, l) local_add((i), (l))
+#define __local_sub(i, l) local_sub((i), (l))
+
+/* 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.
+ *
+ * X86_64: This could be done better if we moved the per cpu data directly
+ * after GS.
+ */
+
+/* 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 /* _ASM_X86_LOCAL_H */