Merge branch 'x86-atomic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'x86-atomic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86: Fix LOCK_PREFIX_HERE for uniprocessor build
  x86, atomic64: In selftest, distinguish x86-64 from 586+
  x86-32: Fix atomic64_inc_not_zero return value convention
  lib: Fix atomic64_inc_not_zero test
  lib: Fix atomic64_add_unless return value convention
  x86-32: Fix atomic64_add_unless return value convention
  lib: Fix atomic64_add_unless test
  x86: Implement atomic[64]_dec_if_positive()
  lib: Only test atomic64_dec_if_positive on archs having it
  x86-32: Rewrite 32-bit atomic64 functions in assembly
  lib: Add self-test for atomic64_t
  x86-32: Allow UP/SMP lock replacement in cmpxchg64
  x86: Add support for lock prefix in alternatives

5 files changed, 265 insertions, 71 deletions

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 714bf2417284..92a9033c14d1 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -28,14 +28,17 @@
  */
 
 #ifdef CONFIG_SMP
-#define LOCK_PREFIX \
+#define LOCK_PREFIX_HERE \
                 ".section .smp_locks,\"a\"\n"   \
                 ".balign 4\n"                   \
-                ".long 661f - .\n" /* offset */ \
+                ".long 671f - .\n" /* offset */ \
                 ".previous\n"                   \
-                "661:\n\tlock; "
+                "671:"
+
+#define LOCK_PREFIX LOCK_PREFIX_HERE "\n\tlock; "
 
 #else /* ! CONFIG_SMP */
+#define LOCK_PREFIX_HERE ""
 #define LOCK_PREFIX ""
 #endif
 
diff --git a/arch/x86/include/asm/atomic.h b/arch/x86/include/asm/atomic.h
index 37b39d27abe0..952a826ac4e5 100644
--- a/arch/x86/include/asm/atomic.h
+++ b/arch/x86/include/asm/atomic.h
@@ -246,6 +246,29 @@ static inline int atomic_add_unless(atomic_t *v, int a, int u)
 
 #define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
 
+/*
+ * atomic_dec_if_positive - decrement by 1 if old value positive
+ * @v: pointer of type atomic_t
+ *
+ * The function returns the old value of *v minus 1, even if
+ * the atomic variable, v, was not decremented.
+ */
+static inline int atomic_dec_if_positive(atomic_t *v)
+{
+        int c, old, dec;
+        c = atomic_read(v);
+        for (;;) {
+                dec = c - 1;
+                if (unlikely(dec < 0))
+                        break;
+                old = atomic_cmpxchg((v), c, dec);
+                if (likely(old == c))
+                        break;
+                c = old;
+        }
+        return dec;
+}
+
 /**
  * atomic_inc_short - increment of a short integer
  * @v: pointer to type int
diff --git a/arch/x86/include/asm/atomic64_32.h b/arch/x86/include/asm/atomic64_32.h
index 03027bf28de5..2a934aa19a43 100644
--- a/arch/x86/include/asm/atomic64_32.h
+++ b/arch/x86/include/asm/atomic64_32.h
@@ -14,109 +14,193 @@ typedef struct {
 
 #define ATOMIC64_INIT(val)      { (val) }
 
-extern u64 atomic64_cmpxchg(atomic64_t *ptr, u64 old_val, u64 new_val);
+#ifdef CONFIG_X86_CMPXCHG64
+#define ATOMIC64_ALTERNATIVE_(f, g) "call atomic64_" #g "_cx8"
+#else
+#define ATOMIC64_ALTERNATIVE_(f, g) ALTERNATIVE("call atomic64_" #f "_386", "call atomic64_" #g "_cx8", X86_FEATURE_CX8)
+#endif
+
+#define ATOMIC64_ALTERNATIVE(f) ATOMIC64_ALTERNATIVE_(f, f)
+
+/**
+ * atomic64_cmpxchg - cmpxchg atomic64 variable
+ * @p: pointer to type atomic64_t
+ * @o: expected value
+ * @n: new value
+ *
+ * Atomically sets @v to @n if it was equal to @o and returns
+ * the old value.
+ */
+
+static inline long long atomic64_cmpxchg(atomic64_t *v, long long o, long long n)
+{
+        return cmpxchg64(&v->counter, o, n);
+}
 
 /**
  * atomic64_xchg - xchg atomic64 variable
- * @ptr:      pointer to type atomic64_t
- * @new_val:  value to assign
+ * @v: pointer to type atomic64_t
+ * @n: value to assign
  *
- * Atomically xchgs the value of @ptr to @new_val and returns
+ * Atomically xchgs the value of @v to @n and returns
  * the old value.
  */
-extern u64 atomic64_xchg(atomic64_t *ptr, u64 new_val);
+static inline long long atomic64_xchg(atomic64_t *v, long long n)
+{
+        long long o;
+        unsigned high = (unsigned)(n >> 32);
+        unsigned low = (unsigned)n;
+        asm volatile(ATOMIC64_ALTERNATIVE(xchg)
+                     : "=A" (o), "+b" (low), "+c" (high)
+                     : "S" (v)
+                     : "memory"
+                     );
+        return o;
+}
 
 /**
  * atomic64_set - set atomic64 variable
- * @ptr:      pointer to type atomic64_t
- * @new_val:  value to assign
+ * @v: pointer to type atomic64_t
+ * @n: value to assign
  *
- * Atomically sets the value of @ptr to @new_val.
+ * Atomically sets the value of @v to @n.
  */
-extern void atomic64_set(atomic64_t *ptr, u64 new_val);
+static inline void atomic64_set(atomic64_t *v, long long i)
+{
+        unsigned high = (unsigned)(i >> 32);
+        unsigned low = (unsigned)i;
+        asm volatile(ATOMIC64_ALTERNATIVE(set)
+                     : "+b" (low), "+c" (high)
+                     : "S" (v)
+                     : "eax", "edx", "memory"
+                     );
+}
 
 /**
  * atomic64_read - read atomic64 variable
- * @ptr:      pointer to type atomic64_t
+ * @v: pointer to type atomic64_t
  *
- * Atomically reads the value of @ptr and returns it.
+ * Atomically reads the value of @v and returns it.
  */
-static inline u64 atomic64_read(atomic64_t *ptr)
+static inline long long atomic64_read(atomic64_t *v)
 {
-        u64 res;
-
-        /*
-         * Note, we inline this atomic64_t primitive because
-         * it only clobbers EAX/EDX and leaves the others
-         * untouched. We also (somewhat subtly) rely on the
-         * fact that cmpxchg8b returns the current 64-bit value
-         * of the memory location we are touching:
-         */
-        asm volatile(
-                "mov %%ebx, %%eax\n\t"
-                "mov %%ecx, %%edx\n\t"
-                LOCK_PREFIX "cmpxchg8b %1\n"
-                        : "=&A" (res)
-                        : "m" (*ptr)
-                );
-
-        return res;
-}
-
-extern u64 atomic64_read(atomic64_t *ptr);
+        long long r;
+        asm volatile(ATOMIC64_ALTERNATIVE(read)
+                     : "=A" (r), "+c" (v)
+                     : : "memory"
+                     );
+        return r;
+ }
 
 /**
  * atomic64_add_return - add and return
- * @delta: integer value to add
- * @ptr:   pointer to type atomic64_t
+ * @i: integer value to add
+ * @v: pointer to type atomic64_t
  *
- * Atomically adds @delta to @ptr and returns @delta + *@ptr
+ * Atomically adds @i to @v and returns @i + *@v
  */
-extern u64 atomic64_add_return(u64 delta, atomic64_t *ptr);
+static inline long long atomic64_add_return(long long i, atomic64_t *v)
+{
+        asm volatile(ATOMIC64_ALTERNATIVE(add_return)
+                     : "+A" (i), "+c" (v)
+                     : : "memory"
+                     );
+        return i;
+}
 
 /*
  * Other variants with different arithmetic operators:
  */
-extern u64 atomic64_sub_return(u64 delta, atomic64_t *ptr);
-extern u64 atomic64_inc_return(atomic64_t *ptr);
-extern u64 atomic64_dec_return(atomic64_t *ptr);
+static inline long long atomic64_sub_return(long long i, atomic64_t *v)
+{
+        asm volatile(ATOMIC64_ALTERNATIVE(sub_return)
+                     : "+A" (i), "+c" (v)
+                     : : "memory"
+                     );
+        return i;
+}
+
+static inline long long atomic64_inc_return(atomic64_t *v)
+{
+        long long a;
+        asm volatile(ATOMIC64_ALTERNATIVE(inc_return)
+                     : "=A" (a)
+                     : "S" (v)
+                     : "memory", "ecx"
+                     );
+        return a;
+}
+
+static inline long long atomic64_dec_return(atomic64_t *v)
+{
+        long long a;
+        asm volatile(ATOMIC64_ALTERNATIVE(dec_return)
+                     : "=A" (a)
+                     : "S" (v)
+                     : "memory", "ecx"
+                     );
+        return a;
+}
 
 /**
  * atomic64_add - add integer to atomic64 variable
- * @delta: integer value to add
- * @ptr:   pointer to type atomic64_t
+ * @i: integer value to add
+ * @v: pointer to type atomic64_t
  *
- * Atomically adds @delta to @ptr.
+ * Atomically adds @i to @v.
  */
-extern void atomic64_add(u64 delta, atomic64_t *ptr);
+static inline long long atomic64_add(long long i, atomic64_t *v)
+{
+        asm volatile(ATOMIC64_ALTERNATIVE_(add, add_return)
+                     : "+A" (i), "+c" (v)
+                     : : "memory"
+                     );
+        return i;
+}
 
 /**
  * atomic64_sub - subtract the atomic64 variable
- * @delta: integer value to subtract
- * @ptr:   pointer to type atomic64_t
+ * @i: integer value to subtract
+ * @v: pointer to type atomic64_t
  *
- * Atomically subtracts @delta from @ptr.
+ * Atomically subtracts @i from @v.
  */
-extern void atomic64_sub(u64 delta, atomic64_t *ptr);
+static inline long long atomic64_sub(long long i, atomic64_t *v)
+{
+        asm volatile(ATOMIC64_ALTERNATIVE_(sub, sub_return)
+                     : "+A" (i), "+c" (v)
+                     : : "memory"
+                     );
+        return i;
+}
 
 /**
  * atomic64_sub_and_test - subtract value from variable and test result
- * @delta: integer value to subtract
- * @ptr:   pointer to type atomic64_t
- *
- * Atomically subtracts @delta from @ptr and returns
+ * @i: integer value to subtract
+ * @v: pointer to type atomic64_t
+  *
+ * Atomically subtracts @i from @v and returns
  * true if the result is zero, or false for all
  * other cases.
  */
-extern int atomic64_sub_and_test(u64 delta, atomic64_t *ptr);
+static inline int atomic64_sub_and_test(long long i, atomic64_t *v)
+{
+        return atomic64_sub_return(i, v) == 0;
+}
 
 /**
  * atomic64_inc - increment atomic64 variable
- * @ptr: pointer to type atomic64_t
+ * @v: pointer to type atomic64_t
  *
- * Atomically increments @ptr by 1.
+ * Atomically increments @v by 1.
  */
-extern void atomic64_inc(atomic64_t *ptr);
+static inline void atomic64_inc(atomic64_t *v)
+{
+        asm volatile(ATOMIC64_ALTERNATIVE_(inc, inc_return)
+                     : : "S" (v)
+                     : "memory", "eax", "ecx", "edx"
+                     );
+}
 
 /**
  * atomic64_dec - decrement atomic64 variable
@@ -124,37 +208,97 @@ extern void atomic64_inc(atomic64_t *ptr);
  *
  * Atomically decrements @ptr by 1.
  */
-extern void atomic64_dec(atomic64_t *ptr);
+static inline void atomic64_dec(atomic64_t *v)
+{
+        asm volatile(ATOMIC64_ALTERNATIVE_(dec, dec_return)
+                     : : "S" (v)
+                     : "memory", "eax", "ecx", "edx"
+                     );
+}
 
 /**
  * atomic64_dec_and_test - decrement and test
- * @ptr: pointer to type atomic64_t
+ * @v: pointer to type atomic64_t
  *
- * Atomically decrements @ptr by 1 and
+ * Atomically decrements @v by 1 and
  * returns true if the result is 0, or false for all other
  * cases.
  */
-extern int atomic64_dec_and_test(atomic64_t *ptr);
+static inline int atomic64_dec_and_test(atomic64_t *v)
+{
+        return atomic64_dec_return(v) == 0;
+}
 
 /**
  * atomic64_inc_and_test - increment and test
- * @ptr: pointer to type atomic64_t
+ * @v: pointer to type atomic64_t
  *
- * Atomically increments @ptr by 1
+ * Atomically increments @v by 1
  * and returns true if the result is zero, or false for all
  * other cases.
  */
-extern int atomic64_inc_and_test(atomic64_t *ptr);
+static inline int atomic64_inc_and_test(atomic64_t *v)
+{
+        return atomic64_inc_return(v) == 0;
+}
 
 /**
  * atomic64_add_negative - add and test if negative
- * @delta: integer value to add
- * @ptr:   pointer to type atomic64_t
+ * @i: integer value to add
+ * @v: pointer to type atomic64_t
  *
- * Atomically adds @delta to @ptr and returns true
+ * Atomically adds @i to @v and returns true
  * if the result is negative, or false when
  * result is greater than or equal to zero.
  */
-extern int atomic64_add_negative(u64 delta, atomic64_t *ptr);
+static inline int atomic64_add_negative(long long i, atomic64_t *v)
+{
+        return atomic64_add_return(i, v) < 0;
+}
+
+/**
+ * atomic64_add_unless - add unless the number is a given value
+ * @v: pointer of type atomic64_t
+ * @a: the amount to add to v...
+ * @u: ...unless v is equal to u.
+ *
+ * Atomically adds @a to @v, so long as it was not @u.
+ * Returns non-zero if @v was not @u, and zero otherwise.
+ */
+static inline int atomic64_add_unless(atomic64_t *v, long long a, long long u)
+{
+        unsigned low = (unsigned)u;
+        unsigned high = (unsigned)(u >> 32);
+        asm volatile(ATOMIC64_ALTERNATIVE(add_unless) "\n\t"
+                     : "+A" (a), "+c" (v), "+S" (low), "+D" (high)
+                     : : "memory");
+        return (int)a;
+}
+
+
+static inline int atomic64_inc_not_zero(atomic64_t *v)
+{
+        int r;
+        asm volatile(ATOMIC64_ALTERNATIVE(inc_not_zero)
+                     : "=a" (r)
+                     : "S" (v)
+                     : "ecx", "edx", "memory"
+                     );
+        return r;
+}
+
+static inline long long atomic64_dec_if_positive(atomic64_t *v)
+{
+        long long r;
+        asm volatile(ATOMIC64_ALTERNATIVE(dec_if_positive)
+                     : "=A" (r)
+                     : "S" (v)
+                     : "ecx", "memory"
+                     );
+        return r;
+}
+
+#undef ATOMIC64_ALTERNATIVE
+#undef ATOMIC64_ALTERNATIVE_
 
 #endif /* _ASM_X86_ATOMIC64_32_H */
diff --git a/arch/x86/include/asm/atomic64_64.h b/arch/x86/include/asm/atomic64_64.h
index b014e235ea8d..49fd1ea22951 100644
--- a/arch/x86/include/asm/atomic64_64.h
+++ b/arch/x86/include/asm/atomic64_64.h
@@ -221,4 +221,27 @@ static inline int atomic64_add_unless(atomic64_t *v, long a, long u)
 
 #define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0)
 
+/*
+ * atomic64_dec_if_positive - decrement by 1 if old value positive
+ * @v: pointer of type atomic_t
+ *
+ * The function returns the old value of *v minus 1, even if
+ * the atomic variable, v, was not decremented.
+ */
+static inline long atomic64_dec_if_positive(atomic64_t *v)
+{
+        long c, old, dec;
+        c = atomic64_read(v);
+        for (;;) {
+                dec = c - 1;
+                if (unlikely(dec < 0))
+                        break;
+                old = atomic64_cmpxchg((v), c, dec);
+                if (likely(old == c))
+                        break;
+                c = old;
+        }
+        return dec;
+}
+
 #endif /* _ASM_X86_ATOMIC64_64_H */
diff --git a/arch/x86/include/asm/cmpxchg_32.h b/arch/x86/include/asm/cmpxchg_32.h
index ffb9bb6b6c37..8859e12dd3cf 100644
--- a/arch/x86/include/asm/cmpxchg_32.h
+++ b/arch/x86/include/asm/cmpxchg_32.h
@@ -271,7 +271,8 @@ extern unsigned long long cmpxchg_486_u64(volatile void *, u64, u64);
         __typeof__(*(ptr)) __ret;                               \
         __typeof__(*(ptr)) __old = (o);                         \
         __typeof__(*(ptr)) __new = (n);                         \
-        alternative_io("call cmpxchg8b_emu",                    \
+        alternative_io(LOCK_PREFIX_HERE                         \
+                        "call cmpxchg8b_emu",                   \
                         "lock; cmpxchg8b (%%esi)" ,             \
                        X86_FEATURE_CX8,                         \
                        "=A" (__ret),                            \