1 files changed, 235 insertions, 0 deletions
diff --git a/arch/x86/include/asm/local.h b/arch/x86/include/asm/local.h
new file mode 100644
index 00000000000..47b9b6f1905
--- /dev/null
+++ b/arch/x86/include/asm/local.h
@@ -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 */