Messages in this thread Patch in this message | | | From | Vineet Gupta <> | Subject | [PATCH 1/4] ARC: add barriers to futex code | Date | Thu, 6 Aug 2015 18:05:20 +0530 |
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The atomic ops on futex need to provide the full barrier just like regular atomics in kernel.
Also remove pagefault_enable/disable in futex_atomic_cmpxchg_inatomic() as core code already does that
Cc: David Hildenbrand <dahi@linux.vnet.ibm.com> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Michel Lespinasse <walken@google.com> Signed-off-by: Vineet Gupta <vgupta@synopsys.com> --- arch/arc/include/asm/futex.h | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/arch/arc/include/asm/futex.h b/arch/arc/include/asm/futex.h index 70cfe16b742d..160656d0a15a 100644 --- a/arch/arc/include/asm/futex.h +++ b/arch/arc/include/asm/futex.h @@ -20,6 +20,7 @@ #define __futex_atomic_op(insn, ret, oldval, uaddr, oparg)\ \ + smp_mb(); \ __asm__ __volatile__( \ "1: llock %1, [%2] \n" \ insn "\n" \ @@ -40,12 +41,14 @@ \ : "=&r" (ret), "=&r" (oldval) \ : "r" (uaddr), "r" (oparg), "ir" (-EFAULT) \ - : "cc", "memory") + : "cc", "memory"); \ + smp_mb(); \ #else /* !CONFIG_ARC_HAS_LLSC */ #define __futex_atomic_op(insn, ret, oldval, uaddr, oparg)\ \ + smp_mb(); \ __asm__ __volatile__( \ "1: ld %1, [%2] \n" \ insn "\n" \ @@ -65,7 +68,8 @@ \ : "=&r" (ret), "=&r" (oldval) \ : "r" (uaddr), "r" (oparg), "ir" (-EFAULT) \ - : "cc", "memory") + : "cc", "memory"); \ + smp_mb(); \ #endif @@ -151,7 +155,7 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, u32 oldval, if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int))) return -EFAULT; - pagefault_disable(); + smp_mb(); __asm__ __volatile__( #ifdef CONFIG_ARC_HAS_LLSC @@ -178,7 +182,7 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, u32 oldval, : "r"(oldval), "r"(newval), "r"(uaddr), "ir"(-EFAULT) : "cc", "memory"); - pagefault_enable(); + smp_mb(); *uval = val; return val; -- 1.9.1
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