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

1 files changed, 61 insertions, 13 deletions

diff --git a/include/asm-generic/atomic64.h b/include/asm-generic/atomic64.h
index 370f01d4450f..c8c7d9fae820 100644
--- a/include/asm-generic/atomic64.h
+++ b/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  */