[PATCHv2 02/11] atomics/x86: reduce arch_cmpxchg64*() instrumentation

[Mark Rutland]

Currently x86's arch_cmpxchg64() and arch_cmpxchg64_local() are
instrumented twice, as they call into instrumented atomics rather than
their arch_ equivalents.

A call to cmpxchg64() results in:

  cmpxchg64()
    kasan_check_write()
    arch_cmpxchg64()
      cmpxchg()
        kasan_check_write()
        arch_cmpxchg()

Let's fix this up and call the arch_ equivalents, resulting in:

  cmpxchg64()
    kasan_check_write()
    arch_cmpxchg64()
      arch_cmpxchg()

Signed-off-by: Mark Rutland <mark.rutl...@arm.com>
Cc: Boqun Feng <boqun.f...@gmail.com>
Cc: Dmitry Vyukov <dvyu...@google.com>
Cc: H. Peter Anvin <h...@zytor.com>
Cc: Ingo Molnar <mi...@redhat.com>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: Will Deacon <will.dea...@arm.com>
---
 arch/x86/include/asm/cmpxchg_64.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/cmpxchg_64.h 
b/arch/x86/include/asm/cmpxchg_64.h
index bfca3b346c74..072e5459fe2f 100644
--- a/arch/x86/include/asm/cmpxchg_64.h
+++ b/arch/x86/include/asm/cmpxchg_64.h
@@ -10,13 +10,13 @@ static inline void set_64bit(volatile u64 *ptr, u64 val)
 #define arch_cmpxchg64(ptr, o, n)                                      \
 ({                                                                     \
        BUILD_BUG_ON(sizeof(*(ptr)) != 8);                              \
-       cmpxchg((ptr), (o), (n));                                       \
+       arch_cmpxchg((ptr), (o), (n));                                  \
 })
 
 #define arch_cmpxchg64_local(ptr, o, n)                                        
\
 ({                                                                     \
        BUILD_BUG_ON(sizeof(*(ptr)) != 8);                              \
-       cmpxchg_local((ptr), (o), (n));                                 \
+       arch_cmpxchg_local((ptr), (o), (n));                            \
 })
 
 #define system_has_cmpxchg_double() boot_cpu_has(X86_FEATURE_CX16)
-- 
2.11.0