[tip:locking/core] locking/atomic/x86: Un-macro-ify atomic ops implementation

tip-bot for Dmitry Vyukov
2017-07-25T13:59:25Z

Commit-ID: ba1c9f83f6330a34cc77ef989e183f54c4fe732e
Gitweb: http://git.kernel.org/tip/ba1c9f83f6330a34cc77ef989e183f54c4fe732e
Author: Dmitry Vyukov <dvyukov@google.com>
AuthorDate: Sat, 17 Jun 2017 11:15:27 +0200
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Wed, 28 Jun 2017 18:55:55 +0200

locking/atomic/x86: Un-macro-ify atomic ops implementation

CPP turns perfectly readable code into a much harder to read syntactic soup.

Ingo suggested to write them out as-is in C and ignore the higher linecount.

Do this.

(As a side effect, plain C functions will be easier to KASAN-instrument as well.)

Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kasan-dev@googlegroups.com
Cc: will.deacon@arm.com
Link: http://lkml.kernel.org/r/a35b983dd3be937a3cf63c4e2db487de2cdc7b8f.1497690003.git.dvyukov@google.com
[ Beautified the C code some more and twiddled the changelog
to mention the linecount increase and the KASAN benefit. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/include/asm/atomic.h | 69 +++++++++++++++++++++-----------
arch/x86/include/asm/atomic64_32.h | 81 +++++++++++++++++++++++++++-----------
arch/x86/include/asm/atomic64_64.h | 67 ++++++++++++++++++++-----------
3 files changed, 147 insertions(+), 70 deletions(-)

diff --git a/arch/x86/include/asm/atomic.h b/arch/x86/include/asm/atomic.h
index 33380b8..0874ebd 100644
--- a/arch/x86/include/asm/atomic.h
+++ b/arch/x86/include/asm/atomic.h
@@ -197,35 +197,56 @@ static inline int atomic_xchg(atomic_t *v, int new)
return xchg(&v->counter, new);
}

-#define ATOMIC_OP(op) \
-static inline void atomic_##op(int i, atomic_t *v) \
-{ \
- asm volatile(LOCK_PREFIX #op"l %1,%0" \
- : "+m" (v->counter) \
- : "ir" (i) \
- : "memory"); \
+static inline void atomic_and(int i, atomic_t *v)
+{
+ asm volatile(LOCK_PREFIX "andl %1,%0"
+ : "+m" (v->counter)
+ : "ir" (i)
+ : "memory");
+}
+
+static inline int atomic_fetch_and(int i, atomic_t *v)
+{
+ int val = atomic_read(v);
+
+ do { } while (!atomic_try_cmpxchg(v, &val, val & i));
+
+ return val;
}

-#define ATOMIC_FETCH_OP(op, c_op) \
-static inline int atomic_fetch_##op(int i, atomic_t *v) \
-{ \
- int val = atomic_read(v); \
- do { \
- } while (!atomic_try_cmpxchg(v, &val, val c_op i)); \
- return val; \
+static inline void atomic_or(int i, atomic_t *v)
+{
+ asm volatile(LOCK_PREFIX "orl %1,%0"
+ : "+m" (v->counter)
+ : "ir" (i)
+ : "memory");
}

-#define ATOMIC_OPS(op, c_op) \
- ATOMIC_OP(op) \
- ATOMIC_FETCH_OP(op, c_op)
+static inline int atomic_fetch_or(int i, atomic_t *v)
+{
+ int val = atomic_read(v);

-ATOMIC_OPS(and, &)
-ATOMIC_OPS(or , |)
-ATOMIC_OPS(xor, ^)
+ do { } while (!atomic_try_cmpxchg(v, &val, val | i));

-#undef ATOMIC_OPS
-#undef ATOMIC_FETCH_OP
-#undef ATOMIC_OP
+ return val;
+}
+
+static inline void atomic_xor(int i, atomic_t *v)
+{
+ asm volatile(LOCK_PREFIX "xorl %1,%0"
+ : "+m" (v->counter)
+ : "ir" (i)
+ : "memory");
+}
+
+static inline int atomic_fetch_xor(int i, atomic_t *v)
+{
+ int val = atomic_read(v);
+
+ do { } while (!atomic_try_cmpxchg(v, &val, val ^ i));
+
+ return val;
+}

/**
* __atomic_add_unless - add unless the number is already a given value
@@ -239,10 +260,12 @@ ATOMIC_OPS(xor, ^)
static __always_inline int __atomic_add_unless(atomic_t *v, int a, int u)
{
int c = atomic_read(v);
+
do {
if (unlikely(c == u))
break;
} while (!atomic_try_cmpxchg(v, &c, c + a));
+
return c;
}

diff --git a/arch/x86/include/asm/atomic64_32.h b/arch/x86/include/asm/atomic64_32.h
index 71d7705..9e206f3 100644
--- a/arch/x86/include/asm/atomic64_32.h
+++ b/arch/x86/include/asm/atomic64_32.h
@@ -312,37 +312,70 @@ static inline long long atomic64_dec_if_positive(atomic64_t *v)
#undef alternative_atomic64
#undef __alternative_atomic64

-#define ATOMIC64_OP(op, c_op) \
-static inline void atomic64_##op(long long i, atomic64_t *v) \
-{ \
- long long old, c = 0; \
- while ((old = atomic64_cmpxchg(v, c, c c_op i)) != c) \
- c = old; \
+static inline void atomic64_and(long long i, atomic64_t *v)
+{
+ long long old, c = 0;
+
+ while ((old = atomic64_cmpxchg(v, c, c & i)) != c)
+ c = old;
}

-#define ATOMIC64_FETCH_OP(op, c_op) \
-static inline long long atomic64_fetch_##op(long long i, atomic64_t *v) \
-{ \
- long long old, c = 0; \
- while ((old = atomic64_cmpxchg(v, c, c c_op i)) != c) \
- c = old; \
- return old; \
+static inline long long atomic64_fetch_and(long long i, atomic64_t *v)
+{
+ long long old, c = 0;
+
+ while ((old = atomic64_cmpxchg(v, c, c & i)) != c)
+ c = old;
+
+ return old;
}

-ATOMIC64_FETCH_OP(add, +)
+static inline void atomic64_or(long long i, atomic64_t *v)
+{
+ long long old, c = 0;

-#define atomic64_fetch_sub(i, v) atomic64_fetch_add(-(i), (v))
+ while ((old = atomic64_cmpxchg(v, c, c | i)) != c)
+ c = old;
+}
+
+static inline long long atomic64_fetch_or(long long i, atomic64_t *v)
+{
+ long long old, c = 0;
+
+ while ((old = atomic64_cmpxchg(v, c, c | i)) != c)
+ c = old;
+
+ return old;
+}

-#define ATOMIC64_OPS(op, c_op) \
- ATOMIC64_OP(op, c_op) \
- ATOMIC64_FETCH_OP(op, c_op)
+static inline void atomic64_xor(long long i, atomic64_t *v)
+{
+ long long old, c = 0;
+
+ while ((old = atomic64_cmpxchg(v, c, c ^ i)) != c)
+ c = old;
+}

-ATOMIC64_OPS(and, &)
-ATOMIC64_OPS(or, |)
-ATOMIC64_OPS(xor, ^)
+static inline long long atomic64_fetch_xor(long long i, atomic64_t *v)
+{
+ long long old, c = 0;
+
+ while ((old = atomic64_cmpxchg(v, c, c ^ i)) != c)
+ c = old;
+
+ return old;
+}

-#undef ATOMIC64_OPS
-#undef ATOMIC64_FETCH_OP
-#undef ATOMIC64_OP
+static inline long long atomic64_fetch_add(long long i, atomic64_t *v)
+{
+ long long old, c = 0;
+
+ while ((old = atomic64_cmpxchg(v, c, c + i)) != c)
+ c = old;
+
+ return old;
+}
+
+#define atomic64_fetch_sub(i, v) atomic64_fetch_add(-(i), (v))

#endif /* _ASM_X86_ATOMIC64_32_H */
diff --git a/arch/x86/include/asm/atomic64_64.h b/arch/x86/include/asm/atomic64_64.h
index 6189a43..8db8879a 100644
--- a/arch/x86/include/asm/atomic64_64.h
+++ b/arch/x86/include/asm/atomic64_64.h
@@ -226,34 +226,55 @@ static inline long atomic64_dec_if_positive(atomic64_t *v)
return dec;
}

-#define ATOMIC64_OP(op) \
-static inline void atomic64_##op(long i, atomic64_t *v) \
-{ \
- asm volatile(LOCK_PREFIX #op"q %1,%0" \
- : "+m" (v->counter) \
- : "er" (i) \
- : "memory"); \
+static inline void atomic64_and(long i, atomic64_t *v)
+{
+ asm volatile(LOCK_PREFIX "andq %1,%0"
+ : "+m" (v->counter)
+ : "er" (i)
+ : "memory");
}

-#define ATOMIC64_FETCH_OP(op, c_op) \
-static inline long atomic64_fetch_##op(long i, atomic64_t *v) \
-{ \
- long val = atomic64_read(v); \
- do { \
- } while (!atomic64_try_cmpxchg(v, &val, val c_op i)); \
- return val; \
+static inline long atomic64_fetch_and(long i, atomic64_t *v)
+{
+ long val = atomic64_read(v);
+
+ do {
+ } while (!atomic64_try_cmpxchg(v, &val, val & i));
+ return val;
}

-#define ATOMIC64_OPS(op, c_op) \
- ATOMIC64_OP(op) \
- ATOMIC64_FETCH_OP(op, c_op)
+static inline void atomic64_or(long i, atomic64_t *v)
+{
+ asm volatile(LOCK_PREFIX "orq %1,%0"
+ : "+m" (v->counter)
+ : "er" (i)
+ : "memory");
+}

-ATOMIC64_OPS(and, &)
-ATOMIC64_OPS(or, |)
-ATOMIC64_OPS(xor, ^)
+static inline long atomic64_fetch_or(long i, atomic64_t *v)
+{
+ long val = atomic64_read(v);

-#undef ATOMIC64_OPS
-#undef ATOMIC64_FETCH_OP
-#undef ATOMIC64_OP
+ do {
+ } while (!atomic64_try_cmpxchg(v, &val, val | i));
+ return val;
+}
+
+static inline void atomic64_xor(long i, atomic64_t *v)
+{
+ asm volatile(LOCK_PREFIX "xorq %1,%0"
+ : "+m" (v->counter)
+ : "er" (i)
+ : "memory");
+}
+
+static inline long atomic64_fetch_xor(long i, atomic64_t *v)
+{
+ long val = atomic64_read(v);
+
+ do {
+ } while (!atomic64_try_cmpxchg(v, &val, val ^ i));
+ return val;
+}

#endif /* _ASM_X86_ATOMIC64_64_H */