locking/atomic: atomic64: support ARCH_ATOMIC

We'd like all architectures to convert to ARCH_ATOMIC, as this will
enable functionality, and once all architectures are converted it will
be possible to make significant cleanups to the atomic headers.

A number of architectures use asm-generic/atomic64.h, and it's
impractical to convert the header and all these architectures in one go.
To make it possible to convert them one-by-one, let's make the
asm-generic implementation function as either atomic64_*() or
arch_atomic64_*() depending on whether ARCH_ATOMIC is selected. To do
this, the generic implementations are prefixed as generic_atomic64_*(),
and preprocessor definitions map atomic64_*()/arch_atomic64_*() onto
these as appropriate.

Once all users are moved over to ARCH_ATOMIC the ifdeffery in the header
can be simplified and/or removed entirely.

For existing users (none of which select ARCH_ATOMIC), there should be
no functional change as a result of this patch.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210525140232.53872-11-mark.rutland@arm.com

include/asm-generic/atomic64.h

@@ -15,19 +15,17 @@ typedef struct {
 
 #define ATOMIC64_INIT(i)	{ (i) }
 
-extern s64 atomic64_read(const atomic64_t *v);
-extern void atomic64_set(atomic64_t *v, s64 i);
-
-#define atomic64_set_release(v, i)	atomic64_set((v), (i))
+extern s64 generic_atomic64_read(const atomic64_t *v);
+extern void generic_atomic64_set(atomic64_t *v, s64 i);
 
 #define ATOMIC64_OP(op)							\
-extern void	 atomic64_##op(s64 a, atomic64_t *v);
+extern void generic_atomic64_##op(s64 a, atomic64_t *v);
 
 #define ATOMIC64_OP_RETURN(op)						\
-extern s64 atomic64_##op##_return(s64 a, atomic64_t *v);
+extern s64 generic_atomic64_##op##_return(s64 a, atomic64_t *v);
 
 #define ATOMIC64_FETCH_OP(op)						\
-extern s64 atomic64_fetch_##op(s64 a, atomic64_t *v);
+extern s64 generic_atomic64_fetch_##op(s64 a, atomic64_t *v);
 
 #define ATOMIC64_OPS(op)	ATOMIC64_OP(op) ATOMIC64_OP_RETURN(op) ATOMIC64_FETCH_OP(op)
 
@@ -46,11 +44,61 @@ ATOMIC64_OPS(xor)
 #undef ATOMIC64_OP_RETURN
 #undef ATOMIC64_OP
 
-extern s64 atomic64_dec_if_positive(atomic64_t *v);
-#define atomic64_dec_if_positive atomic64_dec_if_positive
-extern s64 atomic64_cmpxchg(atomic64_t *v, s64 o, s64 n);
-extern s64 atomic64_xchg(atomic64_t *v, s64 new);
-extern s64 atomic64_fetch_add_unless(atomic64_t *v, s64 a, s64 u);
-#define atomic64_fetch_add_unless atomic64_fetch_add_unless
+extern s64 generic_atomic64_dec_if_positive(atomic64_t *v);
+extern s64 generic_atomic64_cmpxchg(atomic64_t *v, s64 o, s64 n);
+extern s64 generic_atomic64_xchg(atomic64_t *v, s64 new);
+extern s64 generic_atomic64_fetch_add_unless(atomic64_t *v, s64 a, s64 u);
+
+#ifdef CONFIG_ARCH_ATOMIC
+
+#define arch_atomic64_read		generic_atomic64_read
+#define arch_atomic64_set		generic_atomic64_set
+#define arch_atomic64_set_release	generic_atomic64_set
+
+#define arch_atomic64_add		generic_atomic64_add
+#define arch_atomic64_add_return	generic_atomic64_add_return
+#define arch_atomic64_fetch_add		generic_atomic64_fetch_add
+#define arch_atomic64_sub		generic_atomic64_sub
+#define arch_atomic64_sub_return	generic_atomic64_sub_return
+#define arch_atomic64_fetch_sub		generic_atomic64_fetch_sub
+
+#define arch_atomic64_and		generic_atomic64_and
+#define arch_atomic64_fetch_and		generic_atomic64_fetch_and
+#define arch_atomic64_or		generic_atomic64_or
+#define arch_atomic64_fetch_or		generic_atomic64_fetch_or
+#define arch_atomic64_xor		generic_atomic64_xor
+#define arch_atomic64_fetch_xor		generic_atomic64_fetch_xor
+
+#define arch_atomic64_dec_if_positive	generic_atomic64_dec_if_positive
+#define arch_atomic64_cmpxchg		generic_atomic64_cmpxchg
+#define arch_atomic64_xchg		generic_atomic64_xchg
+#define arch_atomic64_fetch_add_unless	generic_atomic64_fetch_add_unless
+
+#else /* CONFIG_ARCH_ATOMIC */
+
+#define atomic64_read			generic_atomic64_read
+#define atomic64_set			generic_atomic64_set
+#define atomic64_set_release		generic_atomic64_set
+
+#define atomic64_add			generic_atomic64_add
+#define atomic64_add_return		generic_atomic64_add_return
+#define atomic64_fetch_add		generic_atomic64_fetch_add
+#define atomic64_sub			generic_atomic64_sub
+#define atomic64_sub_return		generic_atomic64_sub_return
+#define atomic64_fetch_sub		generic_atomic64_fetch_sub
+
+#define atomic64_and			generic_atomic64_and
+#define atomic64_fetch_and		generic_atomic64_fetch_and
+#define atomic64_or			generic_atomic64_or
+#define atomic64_fetch_or		generic_atomic64_fetch_or
+#define atomic64_xor			generic_atomic64_xor
+#define atomic64_fetch_xor		generic_atomic64_fetch_xor
+
+#define atomic64_dec_if_positive	generic_atomic64_dec_if_positive
+#define atomic64_cmpxchg		generic_atomic64_cmpxchg
+#define atomic64_xchg			generic_atomic64_xchg
+#define atomic64_fetch_add_unless	generic_atomic64_fetch_add_unless
+
+#endif /* CONFIG_ARCH_ATOMIC */
 
 #endif  /*  _ASM_GENERIC_ATOMIC64_H  */

lib/atomic64.c

@@ -42,7 +42,7 @@ static inline raw_spinlock_t *lock_addr(const atomic64_t *v)
 	return &atomic64_lock[addr & (NR_LOCKS - 1)].lock;
 }
 
-s64 atomic64_read(const atomic64_t *v)
+s64 generic_atomic64_read(const atomic64_t *v)
 {
 	unsigned long flags;
 	raw_spinlock_t *lock = lock_addr(v);
@@ -53,9 +53,9 @@ s64 atomic64_read(const atomic64_t *v)
 	raw_spin_unlock_irqrestore(lock, flags);
 	return val;
 }
-EXPORT_SYMBOL(atomic64_read);
+EXPORT_SYMBOL(generic_atomic64_read);
 
-void atomic64_set(atomic64_t *v, s64 i)
+void generic_atomic64_set(atomic64_t *v, s64 i)
 {
 	unsigned long flags;
 	raw_spinlock_t *lock = lock_addr(v);
@@ -64,10 +64,10 @@ void atomic64_set(atomic64_t *v, s64 i)
 	v->counter = i;
 	raw_spin_unlock_irqrestore(lock, flags);
 }
-EXPORT_SYMBOL(atomic64_set);
+EXPORT_SYMBOL(generic_atomic64_set);
 
 #define ATOMIC64_OP(op, c_op)						\
-void atomic64_##op(s64 a, atomic64_t *v)				\
+void generic_atomic64_##op(s64 a, atomic64_t *v)			\
 {									\
 	unsigned long flags;						\
 	raw_spinlock_t *lock = lock_addr(v);				\
@@ -76,10 +76,10 @@ void atomic64_##op(s64 a, atomic64_t *v)				\
 	v->counter c_op a;						\
 	raw_spin_unlock_irqrestore(lock, flags);			\
 }									\
-EXPORT_SYMBOL(atomic64_##op);
+EXPORT_SYMBOL(generic_atomic64_##op);
 
 #define ATOMIC64_OP_RETURN(op, c_op)					\
-s64 atomic64_##op##_return(s64 a, atomic64_t *v)			\
+s64 generic_atomic64_##op##_return(s64 a, atomic64_t *v)		\
 {									\
 	unsigned long flags;						\
 	raw_spinlock_t *lock = lock_addr(v);				\
@@ -90,10 +90,10 @@ s64 atomic64_##op##_return(s64 a, atomic64_t *v)			\
 	raw_spin_unlock_irqrestore(lock, flags);			\
 	return val;							\
 }									\
-EXPORT_SYMBOL(atomic64_##op##_return);
+EXPORT_SYMBOL(generic_atomic64_##op##_return);
 
 #define ATOMIC64_FETCH_OP(op, c_op)					\
-s64 atomic64_fetch_##op(s64 a, atomic64_t *v)				\
+s64 generic_atomic64_fetch_##op(s64 a, atomic64_t *v)			\
 {									\
 	unsigned long flags;						\
 	raw_spinlock_t *lock = lock_addr(v);				\
@@ -105,7 +105,7 @@ s64 atomic64_fetch_##op(s64 a, atomic64_t *v)				\
 	raw_spin_unlock_irqrestore(lock, flags);			\
 	return val;							\
 }									\
-EXPORT_SYMBOL(atomic64_fetch_##op);
+EXPORT_SYMBOL(generic_atomic64_fetch_##op);
 
 #define ATOMIC64_OPS(op, c_op)						\
 	ATOMIC64_OP(op, c_op)						\
@@ -130,7 +130,7 @@ ATOMIC64_OPS(xor, ^=)
 #undef ATOMIC64_OP_RETURN
 #undef ATOMIC64_OP
 
-s64 atomic64_dec_if_positive(atomic64_t *v)
+s64 generic_atomic64_dec_if_positive(atomic64_t *v)
 {
 	unsigned long flags;
 	raw_spinlock_t *lock = lock_addr(v);
@@ -143,9 +143,9 @@ s64 atomic64_dec_if_positive(atomic64_t *v)
 	raw_spin_unlock_irqrestore(lock, flags);
 	return val;
 }
-EXPORT_SYMBOL(atomic64_dec_if_positive);
+EXPORT_SYMBOL(generic_atomic64_dec_if_positive);
 
-s64 atomic64_cmpxchg(atomic64_t *v, s64 o, s64 n)
+s64 generic_atomic64_cmpxchg(atomic64_t *v, s64 o, s64 n)
 {
 	unsigned long flags;
 	raw_spinlock_t *lock = lock_addr(v);
@@ -158,9 +158,9 @@ s64 atomic64_cmpxchg(atomic64_t *v, s64 o, s64 n)
 	raw_spin_unlock_irqrestore(lock, flags);
 	return val;
 }
-EXPORT_SYMBOL(atomic64_cmpxchg);
+EXPORT_SYMBOL(generic_atomic64_cmpxchg);
 
-s64 atomic64_xchg(atomic64_t *v, s64 new)
+s64 generic_atomic64_xchg(atomic64_t *v, s64 new)
 {
 	unsigned long flags;
 	raw_spinlock_t *lock = lock_addr(v);
@@ -172,9 +172,9 @@ s64 atomic64_xchg(atomic64_t *v, s64 new)
 	raw_spin_unlock_irqrestore(lock, flags);
 	return val;
 }
-EXPORT_SYMBOL(atomic64_xchg);
+EXPORT_SYMBOL(generic_atomic64_xchg);
 
-s64 atomic64_fetch_add_unless(atomic64_t *v, s64 a, s64 u)
+s64 generic_atomic64_fetch_add_unless(atomic64_t *v, s64 a, s64 u)
 {
 	unsigned long flags;
 	raw_spinlock_t *lock = lock_addr(v);
@@ -188,4 +188,4 @@ s64 atomic64_fetch_add_unless(atomic64_t *v, s64 a, s64 u)
 
 	return val;
 }
-EXPORT_SYMBOL(atomic64_fetch_add_unless);
+EXPORT_SYMBOL(generic_atomic64_fetch_add_unless);