locking/atomics: Flip fallbacks and instrumentationlocking-urgent-2020-06-11

Currently instrumentation of atomic primitives is done at the architecture
level, while composites or fallbacks are provided at the generic level.

The result is that there are no uninstrumented variants of the
fallbacks. Since there is now need of such variants to isolate text poke
from any form of instrumentation invert this ordering.

Doing this means moving the instrumentation into the generic code as
well as having (for now) two variants of the fallbacks.

Notes:

 - the various *cond_read* primitives are not proper fallbacks
   and got moved into linux/atomic.c. No arch_ variants are
   generated because the base primitives smp_cond_load*()
   are instrumented.

 - once all architectures are moved over to arch_atomic_ one of the
   fallback variants can be removed and some 2300 lines reclaimed.

 - atomic_{read,set}*() are no longer double-instrumented

Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lkml.kernel.org/r/20200505134058.769149955@linutronix.de

1 files changed, 13 insertions, 4 deletions

diff --git a/arch/x86/include/asm/atomic.h b/arch/x86/include/asm/atomic.h
index 115127c7ad28..a9ae58826074 100644
--- a/arch/x86/include/asm/atomic.h
+++ b/arch/x86/include/asm/atomic.h
@@ -28,7 +28,7 @@ static __always_inline int arch_atomic_read(const atomic_t *v)
 	 * Note for KASAN: we deliberately don't use READ_ONCE_NOCHECK() here,
 	 * it's non-inlined function that increases binary size and stack usage.
 	 */
-	return READ_ONCE((v)->counter);
+	return __READ_ONCE((v)->counter);
 }
 
 /**
@@ -40,7 +40,7 @@ static __always_inline int arch_atomic_read(const atomic_t *v)
  */
 static __always_inline void arch_atomic_set(atomic_t *v, int i)
 {
-	WRITE_ONCE(v->counter, i);
+	__WRITE_ONCE(v->counter, i);
 }
 
 /**
@@ -166,6 +166,7 @@ static __always_inline int arch_atomic_add_return(int i, atomic_t *v)
 {
 	return i + xadd(&v->counter, i);
 }
+#define arch_atomic_add_return arch_atomic_add_return
 
 /**
  * arch_atomic_sub_return - subtract integer and return
@@ -178,32 +179,37 @@ static __always_inline int arch_atomic_sub_return(int i, atomic_t *v)
 {
 	return arch_atomic_add_return(-i, v);
 }
+#define arch_atomic_sub_return arch_atomic_sub_return
 
 static __always_inline int arch_atomic_fetch_add(int i, atomic_t *v)
 {
 	return xadd(&v->counter, i);
 }
+#define arch_atomic_fetch_add arch_atomic_fetch_add
 
 static __always_inline int arch_atomic_fetch_sub(int i, atomic_t *v)
 {
 	return xadd(&v->counter, -i);
 }
+#define arch_atomic_fetch_sub arch_atomic_fetch_sub
 
 static __always_inline int arch_atomic_cmpxchg(atomic_t *v, int old, int new)
 {
 	return arch_cmpxchg(&v->counter, old, new);
 }
+#define arch_atomic_cmpxchg arch_atomic_cmpxchg
 
-#define arch_atomic_try_cmpxchg arch_atomic_try_cmpxchg
 static __always_inline bool arch_atomic_try_cmpxchg(atomic_t *v, int *old, int new)
 {
 	return try_cmpxchg(&v->counter, old, new);
 }
+#define arch_atomic_try_cmpxchg arch_atomic_try_cmpxchg
 
 static inline int arch_atomic_xchg(atomic_t *v, int new)
 {
 	return arch_xchg(&v->counter, new);
 }
+#define arch_atomic_xchg arch_atomic_xchg
 
 static inline void arch_atomic_and(int i, atomic_t *v)
 {
@@ -221,6 +227,7 @@ static inline int arch_atomic_fetch_and(int i, atomic_t *v)
 
 	return val;
 }
+#define arch_atomic_fetch_and arch_atomic_fetch_and
 
 static inline void arch_atomic_or(int i, atomic_t *v)
 {
@@ -238,6 +245,7 @@ static inline int arch_atomic_fetch_or(int i, atomic_t *v)
 
 	return val;
 }
+#define arch_atomic_fetch_or arch_atomic_fetch_or
 
 static inline void arch_atomic_xor(int i, atomic_t *v)
 {
@@ -255,6 +263,7 @@ static inline int arch_atomic_fetch_xor(int i, atomic_t *v)
 
 	return val;
 }
+#define arch_atomic_fetch_xor arch_atomic_fetch_xor
 
 #ifdef CONFIG_X86_32
 # include <asm/atomic64_32.h>
@@ -262,6 +271,6 @@ static inline int arch_atomic_fetch_xor(int i, atomic_t *v)
 # include <asm/atomic64_64.h>
 #endif
 
-#include <asm-generic/atomic-instrumented.h>
+#define ARCH_ATOMIC
 
 #endif /* _ASM_X86_ATOMIC_H */