Commit af2e7aae authored by Christian Borntraeger's avatar Christian Borntraeger

arm64/spinlock: Replace ACCESS_ONCE READ_ONCE

ACCESS_ONCE does not work reliably on non-scalar types. For
example gcc 4.6 and 4.7 might remove the volatile tag for such
accesses during the SRA (scalar replacement of aggregates) step
(https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145)

Change the spinlock code to replace ACCESS_ONCE with READ_ONCE.
Signed-off-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
Acked-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
parent 4218091c
......@@ -99,12 +99,12 @@ static inline int arch_spin_value_unlocked(arch_spinlock_t lock)
static inline int arch_spin_is_locked(arch_spinlock_t *lock)
{
return !arch_spin_value_unlocked(ACCESS_ONCE(*lock));
return !arch_spin_value_unlocked(READ_ONCE(*lock));
}
static inline int arch_spin_is_contended(arch_spinlock_t *lock)
{
arch_spinlock_t lockval = ACCESS_ONCE(*lock);
arch_spinlock_t lockval = READ_ONCE(*lock);
return (lockval.next - lockval.owner) > 1;
}
#define arch_spin_is_contended arch_spin_is_contended
......
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