local_t: mips extension

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 390 insertions, 39 deletions

diff --git a/include/asm-mips/local.h b/include/asm-mips/local.h
index 9e2d43bae38..ed882c88e0c 100644
--- a/include/asm-mips/local.h
+++ b/include/asm-mips/local.h
@@ -1,60 +1,288 @@
-#ifndef _ASM_LOCAL_H
-#define _ASM_LOCAL_H
+#ifndef _ARCH_MIPS_LOCAL_H
+#define _ARCH_MIPS_LOCAL_H
 
 #include <linux/percpu.h>
+#include <linux/bitops.h>
 #include <asm/atomic.h>
+#include <asm/war.h>
 
-#ifdef CONFIG_32BIT
+typedef struct
+{
+        atomic_long_t a;
+} local_t;
 
-typedef atomic_t local_t;
+#define LOCAL_INIT(i)   { ATOMIC_LONG_INIT(i) }
 
-#define LOCAL_INIT(i)   ATOMIC_INIT(i)
-#define local_read(v)   atomic_read(v)
-#define local_set(v,i)  atomic_set(v,i)
+#define local_read(l)   atomic_long_read(&(l)->a)
+#define local_set(l,i)  atomic_long_set(&(l)->a, (i))
 
-#define local_inc(v)    atomic_inc(v)
-#define local_dec(v)    atomic_dec(v)
-#define local_add(i, v) atomic_add(i, v)
-#define local_sub(i, v) atomic_sub(i, v)
+#define local_add(i,l)  atomic_long_add((i),(&(l)->a))
+#define local_sub(i,l)  atomic_long_sub((i),(&(l)->a))
+#define local_inc(l)    atomic_long_inc(&(l)->a)
+#define local_dec(l)    atomic_long_dec(&(l)->a)
 
-#endif
+/*
+ * Same as above, but return the result value
+ */
+static __inline__ long local_add_return(long i, local_t * l)
+{
+        unsigned long result;
+
+        if (cpu_has_llsc && R10000_LLSC_WAR) {
+                unsigned long temp;
+
+                __asm__ __volatile__(
+                "       .set    mips3                                   \n"
+                "1:"    __LL    "%1, %2         # local_add_return      \n"
+                "       addu    %0, %1, %3                              \n"
+                        __SC    "%0, %2                                 \n"
+                "       beqzl   %0, 1b                                  \n"
+                "       addu    %0, %1, %3                              \n"
+                "       .set    mips0                                   \n"
+                : "=&r" (result), "=&r" (temp), "=m" (l->a.counter)
+                : "Ir" (i), "m" (l->a.counter)
+                : "memory");
+        } else if (cpu_has_llsc) {
+                unsigned long temp;
+
+                __asm__ __volatile__(
+                "       .set    mips3                                   \n"
+                "1:"    __LL    "%1, %2         # local_add_return      \n"
+                "       addu    %0, %1, %3                              \n"
+                        __SC    "%0, %2                                 \n"
+                "       beqz    %0, 1b                                  \n"
+                "       addu    %0, %1, %3                              \n"
+                "       .set    mips0                                   \n"
+                : "=&r" (result), "=&r" (temp), "=m" (l->a.counter)
+                : "Ir" (i), "m" (l->a.counter)
+                : "memory");
+        } else {
+                unsigned long flags;
 
-#ifdef CONFIG_64BIT
+                local_irq_save(flags);
+                result = l->a.counter;
+                result += i;
+                l->a.counter = result;
+                local_irq_restore(flags);
+        }
 
-typedef atomic64_t local_t;
+        return result;
+}
 
-#define LOCAL_INIT(i)   ATOMIC64_INIT(i)
-#define local_read(v)   atomic64_read(v)
-#define local_set(v,i)  atomic64_set(v,i)
+static __inline__ long local_sub_return(long i, local_t * l)
+{
+        unsigned long result;
 
-#define local_inc(v)    atomic64_inc(v)
-#define local_dec(v)    atomic64_dec(v)
-#define local_add(i, v) atomic64_add(i, v)
-#define local_sub(i, v) atomic64_sub(i, v)
+        if (cpu_has_llsc && R10000_LLSC_WAR) {
+                unsigned long temp;
 
-#endif
+                __asm__ __volatile__(
+                "       .set    mips3                                   \n"
+                "1:"    __LL    "%1, %2         # local_sub_return      \n"
+                "       subu    %0, %1, %3                              \n"
+                        __SC    "%0, %2                                 \n"
+                "       beqzl   %0, 1b                                  \n"
+                "       subu    %0, %1, %3                              \n"
+                "       .set    mips0                                   \n"
+                : "=&r" (result), "=&r" (temp), "=m" (l->a.counter)
+                : "Ir" (i), "m" (l->a.counter)
+                : "memory");
+        } else if (cpu_has_llsc) {
+                unsigned long temp;
 
-#define __local_inc(v)          ((v)->counter++)
-#define __local_dec(v)          ((v)->counter--)
-#define __local_add(i,v)        ((v)->counter+=(i))
-#define __local_sub(i,v)        ((v)->counter-=(i))
+                __asm__ __volatile__(
+                "       .set    mips3                                   \n"
+                "1:"    __LL    "%1, %2         # local_sub_return      \n"
+                "       subu    %0, %1, %3                              \n"
+                        __SC    "%0, %2                                 \n"
+                "       beqz    %0, 1b                                  \n"
+                "       subu    %0, %1, %3                              \n"
+                "       .set    mips0                                   \n"
+                : "=&r" (result), "=&r" (temp), "=m" (l->a.counter)
+                : "Ir" (i), "m" (l->a.counter)
+                : "memory");
+        } else {
+                unsigned long flags;
+
+                local_irq_save(flags);
+                result = l->a.counter;
+                result -= i;
+                l->a.counter = result;
+                local_irq_restore(flags);
+        }
+
+        return result;
+}
 
 /*
- * Use these for per-cpu local_t variables: on some archs they are
+ * local_sub_if_positive - conditionally subtract integer from atomic variable
+ * @i: integer value to subtract
+ * @l: pointer of type local_t
+ *
+ * Atomically test @l and subtract @i if @l is greater or equal than @i.
+ * The function returns the old value of @l minus @i.
+ */
+static __inline__ long local_sub_if_positive(long i, local_t * l)
+{
+        unsigned long result;
+
+        if (cpu_has_llsc && R10000_LLSC_WAR) {
+                unsigned long temp;
+
+                __asm__ __volatile__(
+                "       .set    mips3                                   \n"
+                "1:"    __LL    "%1, %2         # local_sub_if_positive\n"
+                "       dsubu   %0, %1, %3                              \n"
+                "       bltz    %0, 1f                                  \n"
+                        __SC    "%0, %2                                 \n"
+                "       .set    noreorder                               \n"
+                "       beqzl   %0, 1b                                  \n"
+                "        dsubu  %0, %1, %3                              \n"
+                "       .set    reorder                                 \n"
+                "1:                                                     \n"
+                "       .set    mips0                                   \n"
+                : "=&r" (result), "=&r" (temp), "=m" (l->a.counter)
+                : "Ir" (i), "m" (l->a.counter)
+                : "memory");
+        } else if (cpu_has_llsc) {
+                unsigned long temp;
+
+                __asm__ __volatile__(
+                "       .set    mips3                                   \n"
+                "1:"    __LL    "%1, %2         # local_sub_if_positive\n"
+                "       dsubu   %0, %1, %3                              \n"
+                "       bltz    %0, 1f                                  \n"
+                        __SC    "%0, %2                                 \n"
+                "       .set    noreorder                               \n"
+                "       beqz    %0, 1b                                  \n"
+                "        dsubu  %0, %1, %3                              \n"
+                "       .set    reorder                                 \n"
+                "1:                                                     \n"
+                "       .set    mips0                                   \n"
+                : "=&r" (result), "=&r" (temp), "=m" (l->a.counter)
+                : "Ir" (i), "m" (l->a.counter)
+                : "memory");
+        } else {
+                unsigned long flags;
+
+                local_irq_save(flags);
+                result = l->a.counter;
+                result -= i;
+                if (result >= 0)
+                        l->a.counter = result;
+                local_irq_restore(flags);
+        }
+
+        return result;
+}
+
+#define local_cmpxchg(l, o, n) \
+        ((long)cmpxchg_local(&((l)->a.counter), (o), (n)))
+#define local_xchg(l, n) (xchg_local(&((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);                                      \
+        while (c != (u) && (old = local_cmpxchg((l), c, c + (a))) != c) \
+                c = old;                                        \
+        c != (u);                                               \
+})
+#define local_inc_not_zero(l) local_add_unless((l), 1, 0)
+
+#define local_dec_return(l) local_sub_return(1,(l))
+#define local_inc_return(l) local_add_return(1,(l))
+
+/*
+ * local_sub_and_test - subtract value from variable and test result
+ * @i: integer value to subtract
+ * @l: pointer of type local_t
+ *
+ * Atomically subtracts @i from @l and returns
+ * true if the result is zero, or false for all
+ * other cases.
+ */
+#define local_sub_and_test(i,l) (local_sub_return((i), (l)) == 0)
+
+/*
+ * local_inc_and_test - increment and test
+ * @l: pointer of type local_t
+ *
+ * Atomically increments @l by 1
+ * and returns true if the result is zero, or false for all
+ * other cases.
+ */
+#define local_inc_and_test(l) (local_inc_return(l) == 0)
+
+/*
+ * local_dec_and_test - decrement by 1 and test
+ * @l: pointer of type local_t
+ *
+ * Atomically decrements @l by 1 and
+ * returns true if the result is 0, or false for all other
+ * cases.
+ */
+#define local_dec_and_test(l) (local_sub_return(1, (l)) == 0)
+
+/*
+ * local_dec_if_positive - decrement by 1 if old value positive
+ * @l: pointer of type local_t
+ */
+#define local_dec_if_positive(l)        local_sub_if_positive(1, l)
+
+/*
+ * local_add_negative - add and test if negative
+ * @l: pointer of type local_t
+ * @i: integer value to add
+ *
+ * Atomically adds @i to @l and returns true
+ * if the result is negative, or false when
+ * result is greater than or equal to zero.
+ */
+#define local_add_negative(i,l) (local_add_return(i, (l)) < 0)
+
+/* 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.
  */
-#define cpu_local_read(v)       local_read(&__get_cpu_var(v))
-#define cpu_local_set(v, i)     local_set(&__get_cpu_var(v), (i))
 
-#define cpu_local_inc(v)        local_inc(&__get_cpu_var(v))
-#define cpu_local_dec(v)        local_dec(&__get_cpu_var(v))
-#define cpu_local_add(i, v)     local_add((i), &__get_cpu_var(v))
-#define cpu_local_sub(i, v)     local_sub((i), &__get_cpu_var(v))
+#define __local_inc(l)          ((l)->a.counter++)
+#define __local_dec(l)          ((l)->a.counter++)
+#define __local_add(i,l)        ((l)->a.counter+=(i))
+#define __local_sub(i,l)        ((l)->a.counter-=(i))
+
+/* 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(v)      __local_inc(&__get_cpu_var(v))
-#define __cpu_local_dec(v)      __local_dec(&__get_cpu_var(v))
-#define __cpu_local_add(i, v)   __local_add((i), &__get_cpu_var(v))
-#define __cpu_local_sub(i, v)   __local_sub((i), &__get_cpu_var(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 /* _ASM_LOCAL_H */
+#endif /* _ARCH_MIPS_LOCAL_H */
diff --git a/include/asm-mips/system.h b/include/asm-mips/system.h
index 290887077e4..d53dd724556 100644
--- a/include/asm-mips/system.h
+++ b/include/asm-mips/system.h
@@ -262,6 +262,58 @@ static inline unsigned long __cmpxchg_u32(volatile int * m, unsigned long old,
         return retval;
 }
 
+static inline unsigned long __cmpxchg_u32_local(volatile int * m,
+        unsigned long old, unsigned long new)
+{
+        __u32 retval;
+
+        if (cpu_has_llsc && R10000_LLSC_WAR) {
+                __asm__ __volatile__(
+                "       .set    push                                    \n"
+                "       .set    noat                                    \n"
+                "       .set    mips3                                   \n"
+                "1:     ll      %0, %2                  # __cmpxchg_u32 \n"
+                "       bne     %0, %z3, 2f                             \n"
+                "       .set    mips0                                   \n"
+                "       move    $1, %z4                                 \n"
+                "       .set    mips3                                   \n"
+                "       sc      $1, %1                                  \n"
+                "       beqzl   $1, 1b                                  \n"
+                "2:                                                     \n"
+                "       .set    pop                                     \n"
+                : "=&r" (retval), "=R" (*m)
+                : "R" (*m), "Jr" (old), "Jr" (new)
+                : "memory");
+        } else if (cpu_has_llsc) {
+                __asm__ __volatile__(
+                "       .set    push                                    \n"
+                "       .set    noat                                    \n"
+                "       .set    mips3                                   \n"
+                "1:     ll      %0, %2                  # __cmpxchg_u32 \n"
+                "       bne     %0, %z3, 2f                             \n"
+                "       .set    mips0                                   \n"
+                "       move    $1, %z4                                 \n"
+                "       .set    mips3                                   \n"
+                "       sc      $1, %1                                  \n"
+                "       beqz    $1, 1b                                  \n"
+                "2:                                                     \n"
+                "       .set    pop                                     \n"
+                : "=&r" (retval), "=R" (*m)
+                : "R" (*m), "Jr" (old), "Jr" (new)
+                : "memory");
+        } else {
+                unsigned long flags;
+
+                local_irq_save(flags);
+                retval = *m;
+                if (retval == old)
+                        *m = new;
+                local_irq_restore(flags);       /* implies memory barrier  */
+        }
+
+        return retval;
+}
+
 #ifdef CONFIG_64BIT
 static inline unsigned long __cmpxchg_u64(volatile int * m, unsigned long old,
         unsigned long new)
@@ -315,10 +367,62 @@ static inline unsigned long __cmpxchg_u64(volatile int * m, unsigned long old,
 
         return retval;
 }
+
+static inline unsigned long __cmpxchg_u64_local(volatile int * m,
+        unsigned long old, unsigned long new)
+{
+        __u64 retval;
+
+        if (cpu_has_llsc && R10000_LLSC_WAR) {
+                __asm__ __volatile__(
+                "       .set    push                                    \n"
+                "       .set    noat                                    \n"
+                "       .set    mips3                                   \n"
+                "1:     lld     %0, %2                  # __cmpxchg_u64 \n"
+                "       bne     %0, %z3, 2f                             \n"
+                "       move    $1, %z4                                 \n"
+                "       scd     $1, %1                                  \n"
+                "       beqzl   $1, 1b                                  \n"
+                "2:                                                     \n"
+                "       .set    pop                                     \n"
+                : "=&r" (retval), "=R" (*m)
+                : "R" (*m), "Jr" (old), "Jr" (new)
+                : "memory");
+        } else if (cpu_has_llsc) {
+                __asm__ __volatile__(
+                "       .set    push                                    \n"
+                "       .set    noat                                    \n"
+                "       .set    mips3                                   \n"
+                "1:     lld     %0, %2                  # __cmpxchg_u64 \n"
+                "       bne     %0, %z3, 2f                             \n"
+                "       move    $1, %z4                                 \n"
+                "       scd     $1, %1                                  \n"
+                "       beqz    $1, 1b                                  \n"
+                "2:                                                     \n"
+                "       .set    pop                                     \n"
+                : "=&r" (retval), "=R" (*m)
+                : "R" (*m), "Jr" (old), "Jr" (new)
+                : "memory");
+        } else {
+                unsigned long flags;
+
+                local_irq_save(flags);
+                retval = *m;
+                if (retval == old)
+                        *m = new;
+                local_irq_restore(flags);       /* implies memory barrier  */
+        }
+
+        return retval;
+}
+
 #else
 extern unsigned long __cmpxchg_u64_unsupported_on_32bit_kernels(
         volatile int * m, unsigned long old, unsigned long new);
 #define __cmpxchg_u64 __cmpxchg_u64_unsupported_on_32bit_kernels
+extern unsigned long __cmpxchg_u64_local_unsupported_on_32bit_kernels(
+        volatile int * m, unsigned long old, unsigned long new);
+#define __cmpxchg_u64_local __cmpxchg_u64_local_unsupported_on_32bit_kernels
 #endif
 
 /* This function doesn't exist, so you'll get a linker error
@@ -338,7 +442,26 @@ static inline unsigned long __cmpxchg(volatile void * ptr, unsigned long old,
         return old;
 }
 
-#define cmpxchg(ptr,old,new) ((__typeof__(*(ptr)))__cmpxchg((ptr), (unsigned long)(old), (unsigned long)(new),sizeof(*(ptr))))
+static inline unsigned long __cmpxchg_local(volatile void * ptr,
+        unsigned long old, unsigned long new, int size)
+{
+        switch (size) {
+        case 4:
+                return __cmpxchg_u32_local(ptr, old, new);
+        case 8:
+                return __cmpxchg_u64_local(ptr, old, new);
+        }
+        __cmpxchg_called_with_bad_pointer();
+        return old;
+}
+
+#define cmpxchg(ptr,old,new) \
+        ((__typeof__(*(ptr)))__cmpxchg((ptr), \
+                (unsigned long)(old), (unsigned long)(new),sizeof(*(ptr))))
+
+#define cmpxchg_local(ptr,old,new) \
+        ((__typeof__(*(ptr)))__cmpxchg_local((ptr), \
+                (unsigned long)(old), (unsigned long)(new),sizeof(*(ptr))))
 
 extern void set_handler (unsigned long offset, void *addr, unsigned long len);
 extern void set_uncached_handler (unsigned long offset, void *addr, unsigned long len);