Add atomic_readandclear_int and atomic_readandclear_long.

3 files changed, 110 insertions, 4 deletions

diff --git a/sys/alpha/include/atomic.h b/sys/alpha/include/atomic.h
index d6869b2..3532a06 100644
--- a/sys/alpha/include/atomic.h
+++ b/sys/alpha/include/atomic.h
@@ -116,6 +116,26 @@ static __inline void atomic_subtract_32(volatile u_int32_t *p, u_int32_t v)
 		: "memory");
 }
 
+static __inline u_int32_t atomic_readandclear_32(volatile u_int32_t *addr)
+{
+	u_int32_t result,temp;
+
+	__asm __volatile (
+		"wmb\n"			/* ensure pending writes have drained */
+		"1:\tldl_l %0,%3\n\t"	/* load current value, asserting lock */
+		"ldiq %1,0\n\t"		/* value to store */
+		"stl_c %1,%2\n\t"	/* attempt to store */
+		"beq %1,2f\n\t"		/* if the store failed, spin */
+		"br 3f\n"		/* it worked, exit */
+		"2:\tbr 1b\n"		/* *addr not updated, loop */
+		"3:\tmb\n"		/* it worked */
+		: "=&r"(result), "=&r"(temp), "=m" (*addr)
+		: "m"(*addr)
+		: "memory");
+
+	return result;
+}
+
 static __inline void atomic_set_64(volatile u_int64_t *p, u_int64_t v)
 {
 	u_int64_t temp;
@@ -188,6 +208,26 @@ static __inline void atomic_subtract_64(volatile u_int64_t *p, u_int64_t v)
 		: "memory");
 }
 
+static __inline u_int64_t atomic_readandclear_64(volatile u_int64_t *addr)
+{
+	u_int64_t result,temp;
+
+	__asm __volatile (
+		"wmb\n"			/* ensure pending writes have drained */
+		"1:\tldq_l %0,%3\n\t"	/* load current value, asserting lock */
+		"ldiq %1,0\n\t"		/* value to store */
+		"stq_c %1,%2\n\t"	/* attempt to store */
+		"beq %1,2f\n\t"		/* if the store failed, spin */
+		"br 3f\n"		/* it worked, exit */
+		"2:\tbr 1b\n"		/* *addr not updated, loop */
+		"3:\tmb\n"		/* it worked */
+		: "=&r"(result), "=&r"(temp), "=m" (*addr)
+		: "m"(*addr)
+		: "memory");
+
+	return result;
+}
+
 #define atomic_set_char		atomic_set_8
 #define atomic_clear_char	atomic_clear_8
 #define atomic_add_char		atomic_add_8
@@ -202,11 +242,13 @@ static __inline void atomic_subtract_64(volatile u_int64_t *p, u_int64_t v)
 #define atomic_clear_int	atomic_clear_32
 #define atomic_add_int		atomic_add_32
 #define atomic_subtract_int	atomic_subtract_32
+#define atomic_readandclear_int	atomic_readandclear_32
 
 #define atomic_set_long		atomic_set_64
 #define atomic_clear_long	atomic_clear_64
 #define atomic_add_long		atomic_add_64
 #define atomic_subtract_long	atomic_subtract_64
+#define atomic_readandclear_long	atomic_readandclear_64
 
 /*
  * Atomically compare the value stored at *p with cmpval and if the
diff --git a/sys/amd64/include/atomic.h b/sys/amd64/include/atomic.h
index 35a710e..b38fd83 100644
--- a/sys/amd64/include/atomic.h
+++ b/sys/amd64/include/atomic.h
@@ -46,11 +46,13 @@
  * atomic_clear_int(P, V)	(*(u_int*)(P) &= ~(V))
  * atomic_add_int(P, V)		(*(u_int*)(P) += (V))
  * atomic_subtract_int(P, V)	(*(u_int*)(P) -= (V))
+ * atomic_readandclear_int(P)	(return  *(u_int*)P; *(u_int*)P = 0;)
  *
  * atomic_set_long(P, V)	(*(u_long*)(P) |= (V))
  * atomic_clear_long(P, V)	(*(u_long*)(P) &= ~(V))
  * atomic_add_long(P, V)	(*(u_long*)(P) += (V))
  * atomic_subtract_long(P, V)	(*(u_long*)(P) -= (V))
+ * atomic_readandclear_long(P)	(return  *(u_long*)P; *(u_long*)P = 0;)
  */
 
 /*
@@ -63,9 +65,9 @@
  */
 #if defined(KLD_MODULE)
 #define ATOMIC_ASM(NAME, TYPE, OP, V)			\
-	extern void atomic_##NAME##_##TYPE(volatile u_##TYPE *p, u_##TYPE v);
+	void atomic_##NAME##_##TYPE(volatile u_##TYPE *p, u_##TYPE v);
 
-extern int atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src);
+int atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src);
 
 #else /* !KLD_MODULE */
 #if defined(SMP)
@@ -218,6 +220,36 @@ atomic_cmpset_ptr(volatile void *dst, void *exp, void *src)
 	return (
 	    atomic_cmpset_int((volatile u_int *)dst, (u_int)exp, (u_int)src));
 }
+
+static __inline u_int
+atomic_readandclear_int(volatile u_int *addr)
+{
+	u_int result;
+
+	__asm __volatile (
+	"	xorl	%0,%0 ;		"
+	"	xchgl	%1,%0 ;		"
+	"# atomic_readandclear_int"
+	: "=&r" (result)		/* 0 (result) */
+	: "m" (*addr));			/* 1 (addr) */
+
+	return (result);
+}
+
+static __inline u_long
+atomic_readandclear_long(volatile u_long *addr)
+{
+	u_long result;
+
+	__asm __volatile (
+	"	xorl	%0,%0 ;		"
+	"	xchgl	%1,%0 ;		"
+	"# atomic_readandclear_int"
+	: "=&r" (result)		/* 0 (result) */
+	: "m" (*addr));			/* 1 (addr) */
+
+	return (result);
+}
 #endif
 
 #endif /* ! _MACHINE_ATOMIC_H_ */
diff --git a/sys/i386/include/atomic.h b/sys/i386/include/atomic.h
index 35a710e..b38fd83 100644
--- a/sys/i386/include/atomic.h
+++ b/sys/i386/include/atomic.h
@@ -46,11 +46,13 @@
  * atomic_clear_int(P, V)	(*(u_int*)(P) &= ~(V))
  * atomic_add_int(P, V)		(*(u_int*)(P) += (V))
  * atomic_subtract_int(P, V)	(*(u_int*)(P) -= (V))
+ * atomic_readandclear_int(P)	(return  *(u_int*)P; *(u_int*)P = 0;)
  *
  * atomic_set_long(P, V)	(*(u_long*)(P) |= (V))
  * atomic_clear_long(P, V)	(*(u_long*)(P) &= ~(V))
  * atomic_add_long(P, V)	(*(u_long*)(P) += (V))
  * atomic_subtract_long(P, V)	(*(u_long*)(P) -= (V))
+ * atomic_readandclear_long(P)	(return  *(u_long*)P; *(u_long*)P = 0;)
  */
 
 /*
@@ -63,9 +65,9 @@
  */
 #if defined(KLD_MODULE)
 #define ATOMIC_ASM(NAME, TYPE, OP, V)			\
-	extern void atomic_##NAME##_##TYPE(volatile u_##TYPE *p, u_##TYPE v);
+	void atomic_##NAME##_##TYPE(volatile u_##TYPE *p, u_##TYPE v);
 
-extern int atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src);
+int atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src);
 
 #else /* !KLD_MODULE */
 #if defined(SMP)
@@ -218,6 +220,36 @@ atomic_cmpset_ptr(volatile void *dst, void *exp, void *src)
 	return (
 	    atomic_cmpset_int((volatile u_int *)dst, (u_int)exp, (u_int)src));
 }
+
+static __inline u_int
+atomic_readandclear_int(volatile u_int *addr)
+{
+	u_int result;
+
+	__asm __volatile (
+	"	xorl	%0,%0 ;		"
+	"	xchgl	%1,%0 ;		"
+	"# atomic_readandclear_int"
+	: "=&r" (result)		/* 0 (result) */
+	: "m" (*addr));			/* 1 (addr) */
+
+	return (result);
+}
+
+static __inline u_long
+atomic_readandclear_long(volatile u_long *addr)
+{
+	u_long result;
+
+	__asm __volatile (
+	"	xorl	%0,%0 ;		"
+	"	xchgl	%1,%0 ;		"
+	"# atomic_readandclear_int"
+	: "=&r" (result)		/* 0 (result) */
+	: "m" (*addr));			/* 1 (addr) */
+
+	return (result);
+}
 #endif
 
 #endif /* ! _MACHINE_ATOMIC_H_ */