[tip: locking/core] locking/atomic: atomic: support ARCH_ATOMIC
From: tip-bot2 for Mark Rutland
Date: Wed May 26 2021 - 07:26:15 EST
The following commit has been merged into the locking/core branch of tip:
Commit-ID: f8b6455a9d381fc513efbec0be0c312b96e6eb6b
Gitweb: https://git.kernel.org/tip/f8b6455a9d381fc513efbec0be0c312b96e6eb6b
Author: Mark Rutland <mark.rutland@xxxxxxx>
AuthorDate: Tue, 25 May 2021 15:02:08 +01:00
Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitterDate: Wed, 26 May 2021 13:20:50 +02:00
locking/atomic: atomic: 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/atomic.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 atomic_*() or arch_atomic_*()
depending on whether ARCH_ATOMIC is selected. To do this, the C
implementations are prefixed as generic_atomic_*(), and preprocessor
definitions map atomic_*()/arch_atomic_*() 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@xxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Boqun Feng <boqun.feng@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20210525140232.53872-10-mark.rutland@xxxxxxx
---
include/asm-generic/atomic.h | 71 ++++++++++++++++++++++++++++++-----
1 file changed, 62 insertions(+), 9 deletions(-)
diff --git a/include/asm-generic/atomic.h b/include/asm-generic/atomic.h
index 316c82a..649060f 100644
--- a/include/asm-generic/atomic.h
+++ b/include/asm-generic/atomic.h
@@ -12,39 +12,47 @@
#include <asm/cmpxchg.h>
#include <asm/barrier.h>
+#ifdef CONFIG_ARCH_ATOMIC
+#define __ga_cmpxchg arch_cmpxchg
+#define __ga_xchg arch_xchg
+#else
+#define __ga_cmpxchg cmpxchg
+#define __ga_xchg xchg
+#endif
+
#ifdef CONFIG_SMP
/* we can build all atomic primitives from cmpxchg */
#define ATOMIC_OP(op, c_op) \
-static inline void atomic_##op(int i, atomic_t *v) \
+static inline void generic_atomic_##op(int i, atomic_t *v) \
{ \
int c, old; \
\
c = v->counter; \
- while ((old = cmpxchg(&v->counter, c, c c_op i)) != c) \
+ while ((old = __ga_cmpxchg(&v->counter, c, c c_op i)) != c) \
c = old; \
}
#define ATOMIC_OP_RETURN(op, c_op) \
-static inline int atomic_##op##_return(int i, atomic_t *v) \
+static inline int generic_atomic_##op##_return(int i, atomic_t *v) \
{ \
int c, old; \
\
c = v->counter; \
- while ((old = cmpxchg(&v->counter, c, c c_op i)) != c) \
+ while ((old = __ga_cmpxchg(&v->counter, c, c c_op i)) != c) \
c = old; \
\
return c c_op i; \
}
#define ATOMIC_FETCH_OP(op, c_op) \
-static inline int atomic_fetch_##op(int i, atomic_t *v) \
+static inline int generic_atomic_fetch_##op(int i, atomic_t *v) \
{ \
int c, old; \
\
c = v->counter; \
- while ((old = cmpxchg(&v->counter, c, c c_op i)) != c) \
+ while ((old = __ga_cmpxchg(&v->counter, c, c c_op i)) != c) \
c = old; \
\
return c; \
@@ -55,7 +63,7 @@ static inline int atomic_fetch_##op(int i, atomic_t *v) \
#include <linux/irqflags.h>
#define ATOMIC_OP(op, c_op) \
-static inline void atomic_##op(int i, atomic_t *v) \
+static inline void generic_atomic_##op(int i, atomic_t *v) \
{ \
unsigned long flags; \
\
@@ -65,7 +73,7 @@ static inline void atomic_##op(int i, atomic_t *v) \
}
#define ATOMIC_OP_RETURN(op, c_op) \
-static inline int atomic_##op##_return(int i, atomic_t *v) \
+static inline int generic_atomic_##op##_return(int i, atomic_t *v) \
{ \
unsigned long flags; \
int ret; \
@@ -78,7 +86,7 @@ static inline int atomic_##op##_return(int i, atomic_t *v) \
}
#define ATOMIC_FETCH_OP(op, c_op) \
-static inline int atomic_fetch_##op(int i, atomic_t *v) \
+static inline int generic_atomic_fetch_##op(int i, atomic_t *v) \
{ \
unsigned long flags; \
int ret; \
@@ -112,10 +120,55 @@ ATOMIC_OP(xor, ^)
#undef ATOMIC_OP_RETURN
#undef ATOMIC_OP
+#undef __ga_cmpxchg
+#undef __ga_xchg
+
+#ifdef CONFIG_ARCH_ATOMIC
+
+#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
+
+#define arch_atomic_read(v) READ_ONCE((v)->counter)
+#define arch_atomic_set(v, i) WRITE_ONCE(((v)->counter), (i))
+
+#define arch_atomic_xchg(ptr, v) (arch_xchg(&(ptr)->counter, (v)))
+#define arch_atomic_cmpxchg(v, old, new) (arch_cmpxchg(&((v)->counter), (old), (new)))
+
+#else /* CONFIG_ARCH_ATOMIC */
+
+#define atomic_add_return generic_atomic_add_return
+#define atomic_sub_return generic_atomic_sub_return
+
+#define atomic_fetch_add generic_atomic_fetch_add
+#define atomic_fetch_sub generic_atomic_fetch_sub
+#define atomic_fetch_and generic_atomic_fetch_and
+#define atomic_fetch_or generic_atomic_fetch_or
+#define atomic_fetch_xor generic_atomic_fetch_xor
+
+#define atomic_add generic_atomic_add
+#define atomic_sub generic_atomic_sub
+#define atomic_and generic_atomic_and
+#define atomic_or generic_atomic_or
+#define atomic_xor generic_atomic_xor
+
#define atomic_read(v) READ_ONCE((v)->counter)
#define atomic_set(v, i) WRITE_ONCE(((v)->counter), (i))
#define atomic_xchg(ptr, v) (xchg(&(ptr)->counter, (v)))
#define atomic_cmpxchg(v, old, new) (cmpxchg(&((v)->counter), (old), (new)))
+#endif /* CONFIG_ARCH_ATOMIC */
+
#endif /* __ASM_GENERIC_ATOMIC_H */