Merge tag 'locking-urgent-2020-06-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull atomics rework from Thomas Gleixner:
 "Peter Zijlstras rework of atomics and fallbacks. This solves two
  problems:

   1) Compilers uninline small atomic_* static inline functions which
      can expose them to instrumentation.

   2) The instrumentation of atomic primitives was done at the
      architecture level while composites or fallbacks were provided at
      the generic level. As a result there are no uninstrumented
      variants of the fallbacks.

  Both issues were in the way of fully isolating fragile entry code
  pathes and especially the text poke int3 handler which is prone to an
  endless recursion problem when anything in that code path is about to
  be instrumented. This was always a problem, but got elevated due to
  the new batch mode updates of tracing.

  The solution is to mark the functions __always_inline and to flip the
  fallback and instrumentation so the non-instrumented variants are at
  the architecture level and the instrumentation is done in generic
  code.

  The latter introduces another fallback variant which will go away once
  all architectures have been moved over to arch_atomic_*"

* tag 'locking-urgent-2020-06-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  locking/atomics: Flip fallbacks and instrumentation
  asm-generic/atomic: Use __always_inline for fallback wrappers

1 files changed, 9 insertions, 0 deletions

diff --git a/arch/x86/include/asm/atomic64_32.h b/arch/x86/include/asm/atomic64_32.h
index 52cfaecb13f9..5efd01b548d1 100644
--- a/arch/x86/include/asm/atomic64_32.h
+++ b/arch/x86/include/asm/atomic64_32.h
@@ -75,6 +75,7 @@ static inline s64 arch_atomic64_cmpxchg(atomic64_t *v, s64 o, s64 n)
 {
 	return arch_cmpxchg64(&v->counter, o, n);
 }
+#define arch_atomic64_cmpxchg arch_atomic64_cmpxchg
 
 /**
  * arch_atomic64_xchg - xchg atomic64 variable
@@ -94,6 +95,7 @@ static inline s64 arch_atomic64_xchg(atomic64_t *v, s64 n)
 			     : "memory");
 	return o;
 }
+#define arch_atomic64_xchg arch_atomic64_xchg
 
 /**
  * arch_atomic64_set - set atomic64 variable
@@ -138,6 +140,7 @@ static inline s64 arch_atomic64_add_return(s64 i, atomic64_t *v)
 			     ASM_NO_INPUT_CLOBBER("memory"));
 	return i;
 }
+#define arch_atomic64_add_return arch_atomic64_add_return
 
 /*
  * Other variants with different arithmetic operators:
@@ -149,6 +152,7 @@ static inline s64 arch_atomic64_sub_return(s64 i, atomic64_t *v)
 			     ASM_NO_INPUT_CLOBBER("memory"));
 	return i;
 }
+#define arch_atomic64_sub_return arch_atomic64_sub_return
 
 static inline s64 arch_atomic64_inc_return(atomic64_t *v)
 {
@@ -242,6 +246,7 @@ static inline int arch_atomic64_add_unless(atomic64_t *v, s64 a, s64 u)
 			     "S" (v) : "memory");
 	return (int)a;
 }
+#define arch_atomic64_add_unless arch_atomic64_add_unless
 
 static inline int arch_atomic64_inc_not_zero(atomic64_t *v)
 {
@@ -281,6 +286,7 @@ static inline s64 arch_atomic64_fetch_and(s64 i, atomic64_t *v)
 
 	return old;
 }
+#define arch_atomic64_fetch_and arch_atomic64_fetch_and
 
 static inline void arch_atomic64_or(s64 i, atomic64_t *v)
 {
@@ -299,6 +305,7 @@ static inline s64 arch_atomic64_fetch_or(s64 i, atomic64_t *v)
 
 	return old;
 }
+#define arch_atomic64_fetch_or arch_atomic64_fetch_or
 
 static inline void arch_atomic64_xor(s64 i, atomic64_t *v)
 {
@@ -317,6 +324,7 @@ static inline s64 arch_atomic64_fetch_xor(s64 i, atomic64_t *v)
 
 	return old;
 }
+#define arch_atomic64_fetch_xor arch_atomic64_fetch_xor
 
 static inline s64 arch_atomic64_fetch_add(s64 i, atomic64_t *v)
 {
@@ -327,6 +335,7 @@ static inline s64 arch_atomic64_fetch_add(s64 i, atomic64_t *v)
 
 	return old;
 }
+#define arch_atomic64_fetch_add arch_atomic64_fetch_add
 
 #define arch_atomic64_fetch_sub(i, v)	arch_atomic64_fetch_add(-(i), (v))