x86, um: ... and asm-x86 move

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

1 files changed, 259 insertions, 0 deletions

diff --git a/arch/x86/include/asm/atomic_32.h b/arch/x86/include/asm/atomic_32.h
new file mode 100644
index 000000000000..14d3f0beb889
--- /dev/null
+++ b/arch/x86/include/asm/atomic_32.h
@@ -0,0 +1,259 @@
+#ifndef ASM_X86__ATOMIC_32_H
+#define ASM_X86__ATOMIC_32_H
+
+#include <linux/compiler.h>
+#include <asm/processor.h>
+#include <asm/cmpxchg.h>
+
+/*
+ * Atomic operations that C can't guarantee us.  Useful for
+ * resource counting etc..
+ */
+
+/*
+ * Make sure gcc doesn't try to be clever and move things around
+ * on us. We need to use _exactly_ the address the user gave us,
+ * not some alias that contains the same information.
+ */
+typedef struct {
+        int counter;
+} atomic_t;
+
+#define ATOMIC_INIT(i)  { (i) }
+
+/**
+ * atomic_read - read atomic variable
+ * @v: pointer of type atomic_t
+ *
+ * Atomically reads the value of @v.
+ */
+#define atomic_read(v)          ((v)->counter)
+
+/**
+ * atomic_set - set atomic variable
+ * @v: pointer of type atomic_t
+ * @i: required value
+ *
+ * Atomically sets the value of @v to @i.
+ */
+#define atomic_set(v, i)        (((v)->counter) = (i))
+
+/**
+ * atomic_add - add integer to atomic variable
+ * @i: integer value to add
+ * @v: pointer of type atomic_t
+ *
+ * Atomically adds @i to @v.
+ */
+static inline void atomic_add(int i, atomic_t *v)
+{
+        asm volatile(LOCK_PREFIX "addl %1,%0"
+                     : "+m" (v->counter)
+                     : "ir" (i));
+}
+
+/**
+ * atomic_sub - subtract integer from atomic variable
+ * @i: integer value to subtract
+ * @v: pointer of type atomic_t
+ *
+ * Atomically subtracts @i from @v.
+ */
+static inline void atomic_sub(int i, atomic_t *v)
+{
+        asm volatile(LOCK_PREFIX "subl %1,%0"
+                     : "+m" (v->counter)
+                     : "ir" (i));
+}
+
+/**
+ * atomic_sub_and_test - subtract value from variable and test result
+ * @i: integer value to subtract
+ * @v: pointer of type atomic_t
+ *
+ * Atomically subtracts @i from @v and returns
+ * true if the result is zero, or false for all
+ * other cases.
+ */
+static inline int atomic_sub_and_test(int i, atomic_t *v)
+{
+        unsigned char c;
+
+        asm volatile(LOCK_PREFIX "subl %2,%0; sete %1"
+                     : "+m" (v->counter), "=qm" (c)
+                     : "ir" (i) : "memory");
+        return c;
+}
+
+/**
+ * atomic_inc - increment atomic variable
+ * @v: pointer of type atomic_t
+ *
+ * Atomically increments @v by 1.
+ */
+static inline void atomic_inc(atomic_t *v)
+{
+        asm volatile(LOCK_PREFIX "incl %0"
+                     : "+m" (v->counter));
+}
+
+/**
+ * atomic_dec - decrement atomic variable
+ * @v: pointer of type atomic_t
+ *
+ * Atomically decrements @v by 1.
+ */
+static inline void atomic_dec(atomic_t *v)
+{
+        asm volatile(LOCK_PREFIX "decl %0"
+                     : "+m" (v->counter));
+}
+
+/**
+ * atomic_dec_and_test - decrement and test
+ * @v: pointer of type atomic_t
+ *
+ * Atomically decrements @v by 1 and
+ * returns true if the result is 0, or false for all other
+ * cases.
+ */
+static inline int atomic_dec_and_test(atomic_t *v)
+{
+        unsigned char c;
+
+        asm volatile(LOCK_PREFIX "decl %0; sete %1"
+                     : "+m" (v->counter), "=qm" (c)
+                     : : "memory");
+        return c != 0;
+}
+
+/**
+ * atomic_inc_and_test - increment and test
+ * @v: pointer of type atomic_t
+ *
+ * Atomically increments @v by 1
+ * and returns true if the result is zero, or false for all
+ * other cases.
+ */
+static inline int atomic_inc_and_test(atomic_t *v)
+{
+        unsigned char c;
+
+        asm volatile(LOCK_PREFIX "incl %0; sete %1"
+                     : "+m" (v->counter), "=qm" (c)
+                     : : "memory");
+        return c != 0;
+}
+
+/**
+ * atomic_add_negative - add and test if negative
+ * @v: pointer of type atomic_t
+ * @i: integer value to add
+ *
+ * Atomically adds @i to @v and returns true
+ * if the result is negative, or false when
+ * result is greater than or equal to zero.
+ */
+static inline int atomic_add_negative(int i, atomic_t *v)
+{
+        unsigned char c;
+
+        asm volatile(LOCK_PREFIX "addl %2,%0; sets %1"
+                     : "+m" (v->counter), "=qm" (c)
+                     : "ir" (i) : "memory");
+        return c;
+}
+
+/**
+ * atomic_add_return - add integer and return
+ * @v: pointer of type atomic_t
+ * @i: integer value to add
+ *
+ * Atomically adds @i to @v and returns @i + @v
+ */
+static inline int atomic_add_return(int i, atomic_t *v)
+{
+        int __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(LOCK_PREFIX "xaddl %0, %1"
+                     : "+r" (i), "+m" (v->counter)
+                     : : "memory");
+        return i + __i;
+
+#ifdef CONFIG_M386
+no_xadd: /* Legacy 386 processor */
+        local_irq_save(flags);
+        __i = atomic_read(v);
+        atomic_set(v, i + __i);
+        local_irq_restore(flags);
+        return i + __i;
+#endif
+}
+
+/**
+ * atomic_sub_return - subtract integer and return
+ * @v: pointer of type atomic_t
+ * @i: integer value to subtract
+ *
+ * Atomically subtracts @i from @v and returns @v - @i
+ */
+static inline int atomic_sub_return(int i, atomic_t *v)
+{
+        return atomic_add_return(-i, v);
+}
+
+#define atomic_cmpxchg(v, old, new) (cmpxchg(&((v)->counter), (old), (new)))
+#define atomic_xchg(v, new) (xchg(&((v)->counter), (new)))
+
+/**
+ * atomic_add_unless - add unless the number is already a given value
+ * @v: pointer of type atomic_t
+ * @a: the amount to add to v...
+ * @u: ...unless v is equal to u.
+ *
+ * Atomically adds @a to @v, so long as @v was not already @u.
+ * Returns non-zero if @v was not @u, and zero otherwise.
+ */
+static inline int atomic_add_unless(atomic_t *v, int a, int u)
+{
+        int c, old;
+        c = atomic_read(v);
+        for (;;) {
+                if (unlikely(c == (u)))
+                        break;
+                old = atomic_cmpxchg((v), c, c + (a));
+                if (likely(old == c))
+                        break;
+                c = old;
+        }
+        return c != (u);
+}
+
+#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
+
+#define atomic_inc_return(v)  (atomic_add_return(1, v))
+#define atomic_dec_return(v)  (atomic_sub_return(1, v))
+
+/* These are x86-specific, used by some header files */
+#define atomic_clear_mask(mask, addr)                           \
+        asm volatile(LOCK_PREFIX "andl %0,%1"                   \
+                     : : "r" (~(mask)), "m" (*(addr)) : "memory")
+
+#define atomic_set_mask(mask, addr)                             \
+        asm volatile(LOCK_PREFIX "orl %0,%1"                            \
+                     : : "r" (mask), "m" (*(addr)) : "memory")
+
+/* Atomic operations are already serializing on x86 */
+#define smp_mb__before_atomic_dec()     barrier()
+#define smp_mb__after_atomic_dec()      barrier()
+#define smp_mb__before_atomic_inc()     barrier()
+#define smp_mb__after_atomic_inc()      barrier()
+
+#include <asm-generic/atomic.h>
+#endif /* ASM_X86__ATOMIC_32_H */