locking/atomic, arch/sh: Implement atomic_fetch_{add,sub,and,or,xor}()

Implement FETCH-OP atomic primitives, these are very similar to the
existing OP-RETURN primitives we already have, except they return the
value of the atomic variable _before_ modification.

This is especially useful for irreversible operations -- such as
bitops (because it becomes impossible to reconstruct the state prior
to modification).

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: linux-arch@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-sh@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/sh/include/asm/atomic-grb.h b/arch/sh/include/asm/atomic-grb.h
index b94df40..d755e96 100644 (file)
--- a/arch/sh/include/asm/atomic-grb.h
+++ b/arch/sh/include/asm/atomic-grb.h
@@ -43,16 +43,42 @@ static inline int atomic_##op##_return(int i, atomic_t *v)          \
        return tmp;                                                     \
 }
 
-#define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_OP_RETURN(op)
+#define ATOMIC_FETCH_OP(op)                                            \
+static inline int atomic_fetch_##op(int i, atomic_t *v)                        \
+{                                                                      \
+       int res, tmp;                                                   \
+                                                                       \
+       __asm__ __volatile__ (                                          \
+               "   .align 2              \n\t"                         \
+               "   mova    1f,   r0      \n\t" /* r0 = end point */    \
+               "   mov    r15,   r1      \n\t" /* r1 = saved sp */     \
+               "   mov    #-6,   r15     \n\t" /* LOGIN: r15 = size */ \
+               "   mov.l  @%2,   %0      \n\t" /* load old value */    \
+               "   mov     %0,   %1      \n\t" /* save old value */    \
+               " " #op "   %3,   %0      \n\t" /* $op */               \
+               "   mov.l   %0,   @%2     \n\t" /* store new value */   \
+               "1: mov     r1,   r15     \n\t" /* LOGOUT */            \
+               : "=&r" (tmp), "=&r" (res), "+r"  (v)                   \
+               : "r"   (i)                                             \
+               : "memory" , "r0", "r1");                               \
+                                                                       \
+       return res;                                                     \
+}
+
+#define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_OP_RETURN(op) ATOMIC_FETCH_OP(op)
 
 ATOMIC_OPS(add)
 ATOMIC_OPS(sub)
 
-ATOMIC_OP(and)
-ATOMIC_OP(or)
-ATOMIC_OP(xor)
+#undef ATOMIC_OPS
+#define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_FETCH_OP(op)
+
+ATOMIC_OPS(and)
+ATOMIC_OPS(or)
+ATOMIC_OPS(xor)
 
 #undef ATOMIC_OPS
+#undef ATOMIC_FETCH_OP
 #undef ATOMIC_OP_RETURN
 #undef ATOMIC_OP
 

diff --git a/arch/sh/include/asm/atomic-irq.h b/arch/sh/include/asm/atomic-irq.h
index 23fcdad..8e2da5f 100644 (file)
--- a/arch/sh/include/asm/atomic-irq.h
+++ b/arch/sh/include/asm/atomic-irq.h
@@ -33,15 +33,38 @@ static inline int atomic_##op##_return(int i, atomic_t *v)          \
        return temp;                                                    \
 }
 
-#define ATOMIC_OPS(op, c_op) ATOMIC_OP(op, c_op) ATOMIC_OP_RETURN(op, c_op)
+#define ATOMIC_FETCH_OP(op, c_op)                                      \
+static inline int atomic_fetch_##op(int i, atomic_t *v)                        \
+{                                                                      \
+       unsigned long temp, flags;                                      \
+                                                                       \
+       raw_local_irq_save(flags);                                      \
+       temp = v->counter;                                              \
+       v->counter c_op i;                                              \
+       raw_local_irq_restore(flags);                                   \
+                                                                       \
+       return temp;                                                    \
+}
+
+#define ATOMIC_OPS(op, c_op)                                           \
+       ATOMIC_OP(op, c_op)                                             \
+       ATOMIC_OP_RETURN(op, c_op)                                      \
+       ATOMIC_FETCH_OP(op, c_op)
 
 ATOMIC_OPS(add, +=)
 ATOMIC_OPS(sub, -=)
-ATOMIC_OP(and, &=)
-ATOMIC_OP(or, |=)
-ATOMIC_OP(xor, ^=)
 
 #undef ATOMIC_OPS
+#define ATOMIC_OPS(op, c_op)                                           \
+       ATOMIC_OP(op, c_op)                                             \
+       ATOMIC_FETCH_OP(op, c_op)
+
+ATOMIC_OPS(and, &=)
+ATOMIC_OPS(or, |=)
+ATOMIC_OPS(xor, ^=)
+
+#undef ATOMIC_OPS
+#undef ATOMIC_FETCH_OP
 #undef ATOMIC_OP_RETURN
 #undef ATOMIC_OP
 

diff --git a/arch/sh/include/asm/atomic-llsc.h b/arch/sh/include/asm/atomic-llsc.h
index 33d34b1..caea2c4 100644 (file)
--- a/arch/sh/include/asm/atomic-llsc.h
+++ b/arch/sh/include/asm/atomic-llsc.h
@@ -48,15 +48,39 @@ static inline int atomic_##op##_return(int i, atomic_t *v)          \
        return temp;                                                    \
 }
 
-#define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_OP_RETURN(op)
+#define ATOMIC_FETCH_OP(op)                                            \
+static inline int atomic_fetch_##op(int i, atomic_t *v)                        \
+{                                                                      \
+       unsigned long res, temp;                                        \
+                                                                       \
+       __asm__ __volatile__ (                                          \
+"1:    movli.l @%3, %0         ! atomic_fetch_" #op "  \n"             \
+"      mov %0, %1                                      \n"             \
+"      " #op " %2, %0                                  \n"             \
+"      movco.l %0, @%3                                 \n"             \
+"      bf      1b                                      \n"             \
+"      synco                                           \n"             \
+       : "=&z" (temp), "=&z" (res)                                     \
+       : "r" (i), "r" (&v->counter)                                    \
+       : "t");                                                         \
+                                                                       \
+       return res;                                                     \
+}
+
+#define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_OP_RETURN(op) ATOMIC_FETCH_OP(op)
 
 ATOMIC_OPS(add)
 ATOMIC_OPS(sub)
-ATOMIC_OP(and)
-ATOMIC_OP(or)
-ATOMIC_OP(xor)
 
 #undef ATOMIC_OPS
+#define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_FETCH_OP(op)
+
+ATOMIC_OPS(and)
+ATOMIC_OPS(or)
+ATOMIC_OPS(xor)
+
+#undef ATOMIC_OPS
+#undef ATOMIC_FETCH_OP
 #undef ATOMIC_OP_RETURN
 #undef ATOMIC_OP
 

diff --git a/arch/sh/include/asm/atomic.h b/arch/sh/include/asm/atomic.h
index c399e1c..d93ed7c 100644 (file)
--- a/arch/sh/include/asm/atomic.h
+++ b/arch/sh/include/asm/atomic.h
@@ -25,6 +25,8 @@
 #include <asm/atomic-irq.h>
 #endif
 
+#define atomic_fetch_or atomic_fetch_or
+
 #define atomic_add_negative(a, v)      (atomic_add_return((a), (v)) < 0)
 #define atomic_dec_return(v)           atomic_sub_return(1, (v))
 #define atomic_inc_return(v)           atomic_add_return(1, (v))