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-rw-r--r--include/asm-generic/atomic.h257
1 files changed, 99 insertions, 158 deletions
diff --git a/include/asm-generic/atomic.h b/include/asm-generic/atomic.h
index 33bd2de3bc1e..22142c71d35a 100644
--- a/include/asm-generic/atomic.h
+++ b/include/asm-generic/atomic.h
@@ -1,192 +1,133 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
- * Generic C implementation of atomic counter operations. Usable on
- * UP systems only. Do not include in machine independent code.
- *
- * Originally implemented for MN10300.
+ * Generic C implementation of atomic counter operations. Do not include in
+ * machine independent code.
*
* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public Licence
- * as published by the Free Software Foundation; either version
- * 2 of the Licence, or (at your option) any later version.
*/
#ifndef __ASM_GENERIC_ATOMIC_H
#define __ASM_GENERIC_ATOMIC_H
#include <asm/cmpxchg.h>
+#include <asm/barrier.h>
#ifdef CONFIG_SMP
-/* Force people to define core atomics */
-# if !defined(atomic_add_return) || !defined(atomic_sub_return) || \
- !defined(atomic_clear_mask) || !defined(atomic_set_mask)
-# error "SMP requires a little arch-specific magic"
-# endif
-#endif
-
-/*
- * Atomic operations that C can't guarantee us. Useful for
- * resource counting etc..
- */
-
-#define ATOMIC_INIT(i) { (i) }
-#ifdef __KERNEL__
+/* we can build all atomic primitives from cmpxchg */
-/**
- * atomic_read - read atomic variable
- * @v: pointer of type atomic_t
- *
- * Atomically reads the value of @v.
- */
-#ifndef atomic_read
-#define atomic_read(v) (*(volatile int *)&(v)->counter)
-#endif
-
-/**
- * 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))
-
-#include <linux/irqflags.h>
-
-/**
- * atomic_add_return - add integer to atomic variable
- * @i: integer value to add
- * @v: pointer of type atomic_t
- *
- * Atomically adds @i to @v and returns the result
- */
-#ifndef atomic_add_return
-static inline int atomic_add_return(int i, atomic_t *v)
-{
- unsigned long flags;
- int temp;
-
- raw_local_irq_save(flags); /* Don't trace it in an irqsoff handler */
- temp = v->counter;
- temp += i;
- v->counter = temp;
- raw_local_irq_restore(flags);
-
- return temp;
+#define ATOMIC_OP(op, c_op) \
+static inline void generic_atomic_##op(int i, atomic_t *v) \
+{ \
+ int c, old; \
+ \
+ c = v->counter; \
+ while ((old = arch_cmpxchg(&v->counter, c, c c_op i)) != c) \
+ c = old; \
}
-#endif
-/**
- * atomic_sub_return - subtract integer from atomic variable
- * @i: integer value to subtract
- * @v: pointer of type atomic_t
- *
- * Atomically subtracts @i from @v and returns the result
- */
-#ifndef atomic_sub_return
-static inline int atomic_sub_return(int i, atomic_t *v)
-{
- unsigned long flags;
- int temp;
-
- raw_local_irq_save(flags); /* Don't trace it in an irqsoff handler */
- temp = v->counter;
- temp -= i;
- v->counter = temp;
- raw_local_irq_restore(flags);
-
- return temp;
+#define ATOMIC_OP_RETURN(op, c_op) \
+static inline int generic_atomic_##op##_return(int i, atomic_t *v) \
+{ \
+ int c, old; \
+ \
+ c = v->counter; \
+ while ((old = arch_cmpxchg(&v->counter, c, c c_op i)) != c) \
+ c = old; \
+ \
+ return c c_op i; \
}
-#endif
-static inline int atomic_add_negative(int i, atomic_t *v)
-{
- return atomic_add_return(i, v) < 0;
+#define ATOMIC_FETCH_OP(op, c_op) \
+static inline int generic_atomic_fetch_##op(int i, atomic_t *v) \
+{ \
+ int c, old; \
+ \
+ c = v->counter; \
+ while ((old = arch_cmpxchg(&v->counter, c, c c_op i)) != c) \
+ c = old; \
+ \
+ return c; \
}
-static inline void atomic_add(int i, atomic_t *v)
-{
- atomic_add_return(i, v);
-}
+#else
-static inline void atomic_sub(int i, atomic_t *v)
-{
- atomic_sub_return(i, v);
+#include <linux/irqflags.h>
+
+#define ATOMIC_OP(op, c_op) \
+static inline void generic_atomic_##op(int i, atomic_t *v) \
+{ \
+ unsigned long flags; \
+ \
+ raw_local_irq_save(flags); \
+ v->counter = v->counter c_op i; \
+ raw_local_irq_restore(flags); \
}
-static inline void atomic_inc(atomic_t *v)
-{
- atomic_add_return(1, v);
+#define ATOMIC_OP_RETURN(op, c_op) \
+static inline int generic_atomic_##op##_return(int i, atomic_t *v) \
+{ \
+ unsigned long flags; \
+ int ret; \
+ \
+ raw_local_irq_save(flags); \
+ ret = (v->counter = v->counter c_op i); \
+ raw_local_irq_restore(flags); \
+ \
+ return ret; \
}
-static inline void atomic_dec(atomic_t *v)
-{
- atomic_sub_return(1, v);
+#define ATOMIC_FETCH_OP(op, c_op) \
+static inline int generic_atomic_fetch_##op(int i, atomic_t *v) \
+{ \
+ unsigned long flags; \
+ int ret; \
+ \
+ raw_local_irq_save(flags); \
+ ret = v->counter; \
+ v->counter = v->counter c_op i; \
+ raw_local_irq_restore(flags); \
+ \
+ return ret; \
}
-#define atomic_dec_return(v) atomic_sub_return(1, (v))
-#define atomic_inc_return(v) atomic_add_return(1, (v))
+#endif /* CONFIG_SMP */
-#define atomic_sub_and_test(i, v) (atomic_sub_return((i), (v)) == 0)
-#define atomic_dec_and_test(v) (atomic_dec_return(v) == 0)
-#define atomic_inc_and_test(v) (atomic_inc_return(v) == 0)
+ATOMIC_OP_RETURN(add, +)
+ATOMIC_OP_RETURN(sub, -)
-#define atomic_xchg(ptr, v) (xchg(&(ptr)->counter, (v)))
-#define atomic_cmpxchg(v, old, new) (cmpxchg(&((v)->counter), (old), (new)))
+ATOMIC_FETCH_OP(add, +)
+ATOMIC_FETCH_OP(sub, -)
+ATOMIC_FETCH_OP(and, &)
+ATOMIC_FETCH_OP(or, |)
+ATOMIC_FETCH_OP(xor, ^)
-static inline int __atomic_add_unless(atomic_t *v, int a, int u)
-{
- int c, old;
- c = atomic_read(v);
- while (c != u && (old = atomic_cmpxchg(v, c, c + a)) != c)
- c = old;
- return c;
-}
+ATOMIC_OP(add, +)
+ATOMIC_OP(sub, -)
+ATOMIC_OP(and, &)
+ATOMIC_OP(or, |)
+ATOMIC_OP(xor, ^)
-/**
- * atomic_clear_mask - Atomically clear bits in atomic variable
- * @mask: Mask of the bits to be cleared
- * @v: pointer of type atomic_t
- *
- * Atomically clears the bits set in @mask from @v
- */
-#ifndef atomic_clear_mask
-static inline void atomic_clear_mask(unsigned long mask, atomic_t *v)
-{
- unsigned long flags;
-
- mask = ~mask;
- raw_local_irq_save(flags); /* Don't trace it in a irqsoff handler */
- v->counter &= mask;
- raw_local_irq_restore(flags);
-}
-#endif
+#undef ATOMIC_FETCH_OP
+#undef ATOMIC_OP_RETURN
+#undef ATOMIC_OP
-/**
- * atomic_set_mask - Atomically set bits in atomic variable
- * @mask: Mask of the bits to be set
- * @v: pointer of type atomic_t
- *
- * Atomically sets the bits set in @mask in @v
- */
-#ifndef atomic_set_mask
-static inline void atomic_set_mask(unsigned int mask, atomic_t *v)
-{
- unsigned long flags;
-
- raw_local_irq_save(flags); /* Don't trace it in a irqsoff handler */
- v->counter |= mask;
- raw_local_irq_restore(flags);
-}
-#endif
+#define arch_atomic_add_return generic_atomic_add_return
+#define arch_atomic_sub_return generic_atomic_sub_return
+
+#define arch_atomic_fetch_add generic_atomic_fetch_add
+#define arch_atomic_fetch_sub generic_atomic_fetch_sub
+#define arch_atomic_fetch_and generic_atomic_fetch_and
+#define arch_atomic_fetch_or generic_atomic_fetch_or
+#define arch_atomic_fetch_xor generic_atomic_fetch_xor
+
+#define arch_atomic_add generic_atomic_add
+#define arch_atomic_sub generic_atomic_sub
+#define arch_atomic_and generic_atomic_and
+#define arch_atomic_or generic_atomic_or
+#define arch_atomic_xor generic_atomic_xor
-/* Assume that atomic operations are already serializing */
-#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()
+#define arch_atomic_read(v) READ_ONCE((v)->counter)
+#define arch_atomic_set(v, i) WRITE_ONCE(((v)->counter), (i))
-#endif /* __KERNEL__ */
#endif /* __ASM_GENERIC_ATOMIC_H */
generated by cgit (git 2.34.1) at 2025-12-25 03:57:18 +0000