Re: [PATCH 1/3] asm-generic/atomic64: Add support for ARCH_ATOMIC

From: Christophe Leroy
Date: Wed Nov 11 2020 - 08:39:21 EST

Hello,

Le 11/11/2020 à 12:07, Nicholas Piggin a écrit :
This passes atomic64 selftest on ppc32 on qemu (uniprocessor only)
both before and after powerpc is converted to use ARCH_ATOMIC.

Can you explain what this change does and why it is needed ?

Christophe


Signed-off-by: Nicholas Piggin <npiggin@xxxxxxxxx>
---
include/asm-generic/atomic64.h | 70 +++++++++++++++++++++++++++-------
lib/atomic64.c | 36 ++++++++---------
2 files changed, 75 insertions(+), 31 deletions(-)

diff --git a/include/asm-generic/atomic64.h b/include/asm-generic/atomic64.h
index 370f01d4450f..2b1ecb591bb9 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 __atomic64_read(const atomic64_t *v);
+extern void __atomic64_set(atomic64_t *v, s64 i);
#define ATOMIC64_OP(op) \
-extern void atomic64_##op(s64 a, atomic64_t *v);
+extern void __atomic64_##op(s64 a, atomic64_t *v);
#define ATOMIC64_OP_RETURN(op) \
-extern s64 atomic64_##op##_return(s64 a, atomic64_t *v);
+extern s64 __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 __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 +44,57 @@ 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 __atomic64_dec_if_positive(atomic64_t *v);
+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);
+
+#ifdef ARCH_ATOMIC
+#define arch_atomic64_read __atomic64_read
+#define arch_atomic64_set __atomic64_set
+#define arch_atomic64_add __atomic64_add
+#define arch_atomic64_add_return __atomic64_add_return
+#define arch_atomic64_fetch_add __atomic64_fetch_add
+#define arch_atomic64_sub __atomic64_sub
+#define arch_atomic64_sub_return __atomic64_sub_return
+#define arch_atomic64_fetch_sub __atomic64_fetch_sub
+#define arch_atomic64_and __atomic64_and
+#define arch_atomic64_and_return __atomic64_and_return
+#define arch_atomic64_fetch_and __atomic64_fetch_and
+#define arch_atomic64_or __atomic64_or
+#define arch_atomic64_or_return __atomic64_or_return
+#define arch_atomic64_fetch_or __atomic64_fetch_or
+#define arch_atomic64_xor __atomic64_xor
+#define arch_atomic64_xor_return __atomic64_xor_return
+#define arch_atomic64_fetch_xor __atomic64_fetch_xor
+#define arch_atomic64_xchg __atomic64_xchg
+#define arch_atomic64_cmpxchg __atomic64_cmpxchg
+#define arch_atomic64_set_release(v, i) __atomic64_set((v), (i))
+#define arch_atomic64_dec_if_positive __atomic64_dec_if_positive
+#define arch_atomic64_fetch_add_unless __atomic64_fetch_add_unless
+#else
+#define atomic64_read __atomic64_read
+#define atomic64_set __atomic64_set
+#define atomic64_add __atomic64_add
+#define atomic64_add_return __atomic64_add_return
+#define atomic64_fetch_add __atomic64_fetch_add
+#define atomic64_sub __atomic64_sub
+#define atomic64_sub_return __atomic64_sub_return
+#define atomic64_fetch_sub __atomic64_fetch_sub
+#define atomic64_and __atomic64_and
+#define atomic64_and_return __atomic64_and_return
+#define atomic64_fetch_and __atomic64_fetch_and
+#define atomic64_or __atomic64_or
+#define atomic64_or_return __atomic64_or_return
+#define atomic64_fetch_or __atomic64_fetch_or
+#define atomic64_xor __atomic64_xor
+#define atomic64_xor_return __atomic64_xor_return
+#define atomic64_fetch_xor __atomic64_fetch_xor
+#define atomic64_xchg __atomic64_xchg
+#define atomic64_cmpxchg __atomic64_cmpxchg
+#define atomic64_set_release(v, i) __atomic64_set((v), (i))
+#define atomic64_dec_if_positive __atomic64_dec_if_positive
+#define atomic64_fetch_add_unless __atomic64_fetch_add_unless
+#endif
#endif /* _ASM_GENERIC_ATOMIC64_H */
diff --git a/lib/atomic64.c b/lib/atomic64.c
index e98c85a99787..05aba5e3268f 100644
--- a/lib/atomic64.c
+++ b/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 __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(__atomic64_read);
-void atomic64_set(atomic64_t *v, s64 i)
+void __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(__atomic64_set);
#define ATOMIC64_OP(op, c_op) \
-void atomic64_##op(s64 a, atomic64_t *v) \
+void __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(__atomic64_##op);
#define ATOMIC64_OP_RETURN(op, c_op) \
-s64 atomic64_##op##_return(s64 a, atomic64_t *v) \
+s64 __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(__atomic64_##op##_return);
#define ATOMIC64_FETCH_OP(op, c_op) \
-s64 atomic64_fetch_##op(s64 a, atomic64_t *v) \
+s64 __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(__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 __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(__atomic64_dec_if_positive);
-s64 atomic64_cmpxchg(atomic64_t *v, s64 o, s64 n)
+s64 __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(__atomic64_cmpxchg);
-s64 atomic64_xchg(atomic64_t *v, s64 new)
+s64 __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(__atomic64_xchg);
-s64 atomic64_fetch_add_unless(atomic64_t *v, s64 a, s64 u)
+s64 __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(__atomic64_fetch_add_unless);