[tip:locking/core] locking/atomics/x86: Reduce arch_cmpxchg64*() instrumentation

[tip-bot for Mark Rutland <tipbot@zytor.com>]

Commit-ID:  00d5551cc4eec0fc39c3871c25c613553acfb866
Gitweb:     https://git.kernel.org/tip/00d5551cc4eec0fc39c3871c25c613553acfb866
Author:     Mark Rutland <mark.rutland@arm.com>
AuthorDate: Mon, 16 Jul 2018 12:30:07 +0100
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Wed, 25 Jul 2018 11:53:58 +0200

locking/atomics/x86: Reduce arch_cmpxchg64*() instrumentation

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.rutland@arm.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: andy.shevchenko@gmail.com
Cc: arnd@arndb.de
Cc: aryabinin@virtuozzo.com
Cc: catalin.marinas@arm.com
Cc: glider@google.com
Cc: linux-arm-kernel@lists.infradead.org
Cc: parri.andrea@gmail.com
Cc: peter@hurleysoftware.com
Link: http://lkml.kernel.org/r/20180716113017.3909-3-mark.rutland@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 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)