// SPDX-License-Identifier: GPL-2.0+//// An earlier version of this file appeared in the companion webpage for// "Frightening small children and disconcerting grown-ups: Concurrency// in the Linux kernel" by Alglave, Maranget, McKenney, Parri, and Stern,// which appeared in ASPLOS 2018. // ONCEREAD_ONCE(X) __load{once}(X)WRITE_ONCE(X,V) { __store{once}(X,V); } // Release Acquire and friendssmp_store_release(X,V) { __store{release}(*X,V); }smp_load_acquire(X) __load{acquire}(*X)rcu_assign_pointer(X,V) { __store{release}(X,V); }rcu_dereference(X) __load{once}(X)smp_store_mb(X,V) { __store{once}(X,V); __fence{mb}; } // Fencessmp_mb() { __fence{mb}; }smp_rmb() { __fence{rmb}; }smp_wmb() { __fence{wmb}; }smp_mb__before_atomic() { __fence{before-atomic}; }smp_mb__after_atomic() { __fence{after-atomic}; }smp_mb__after_spinlock() { __fence{after-spinlock}; }smp_mb__after_unlock_lock() { __fence{after-unlock-lock}; }smp_mb__after_srcu_read_unlock() { __fence{after-srcu-read-unlock}; }barrier() { __fence{barrier}; } // Exchangexchg(X,V)  __xchg{mb}(X,V)xchg_relaxed(X,V) __xchg{once}(X,V)xchg_release(X,V) __xchg{release}(X,V)xchg_acquire(X,V) __xchg{acquire}(X,V)cmpxchg(X,V,W) __cmpxchg{mb}(X,V,W)cmpxchg_relaxed(X,V,W) __cmpxchg{once}(X,V,W)cmpxchg_acquire(X,V,W) __cmpxchg{acquire}(X,V,W)cmpxchg_release(X,V,W) __cmpxchg{release}(X,V,W) // Spinlocksspin_lock(X) { __lock(X); }spin_unlock(X) { __unlock(X); }spin_trylock(X) __trylock(X)spin_is_locked(X) __islocked(X) // RCUrcu_read_lock() { __fence{rcu-lock}; }rcu_read_unlock() { __fence{rcu-unlock}; }synchronize_rcu() { __fence{sync-rcu}; }synchronize_rcu_expedited() { __fence{sync-rcu}; } // SRCUsrcu_read_lock(X) __load{srcu-lock}(*X)srcu_read_unlock(X,Y) { __store{srcu-unlock}(*X,Y); }srcu_down_read(X) __load{srcu-lock}(*X)srcu_up_read(X,Y) { __store{srcu-unlock}(*X,Y); }synchronize_srcu(X)  { __srcu{sync-srcu}(X); }synchronize_srcu_expedited(X)  { __srcu{sync-srcu}(X); } // Atomicatomic_read(X) READ_ONCE(*X)atomic_set(X,V) { WRITE_ONCE(*X,V); }atomic_read_acquire(X) smp_load_acquire(X)atomic_set_release(X,V) { smp_store_release(X,V); } atomic_add(V,X) { __atomic_op(X,+,V); }atomic_sub(V,X) { __atomic_op(X,-,V); }atomic_inc(X)   { __atomic_op(X,+,1); }atomic_dec(X)   { __atomic_op(X,-,1); } atomic_add_return(V,X) __atomic_op_return{mb}(X,+,V)atomic_add_return_relaxed(V,X) __atomic_op_return{once}(X,+,V)atomic_add_return_acquire(V,X) __atomic_op_return{acquire}(X,+,V)atomic_add_return_release(V,X) __atomic_op_return{release}(X,+,V)atomic_fetch_add(V,X) __atomic_fetch_op{mb}(X,+,V)atomic_fetch_add_relaxed(V,X) __atomic_fetch_op{once}(X,+,V)atomic_fetch_add_acquire(V,X) __atomic_fetch_op{acquire}(X,+,V)atomic_fetch_add_release(V,X) __atomic_fetch_op{release}(X,+,V) atomic_inc_return(X) __atomic_op_return{mb}(X,+,1)atomic_inc_return_relaxed(X) __atomic_op_return{once}(X,+,1)atomic_inc_return_acquire(X) __atomic_op_return{acquire}(X,+,1)atomic_inc_return_release(X) __atomic_op_return{release}(X,+,1)atomic_fetch_inc(X) __atomic_fetch_op{mb}(X,+,1)atomic_fetch_inc_relaxed(X) __atomic_fetch_op{once}(X,+,1)atomic_fetch_inc_acquire(X) __atomic_fetch_op{acquire}(X,+,1)atomic_fetch_inc_release(X) __atomic_fetch_op{release}(X,+,1) atomic_sub_return(V,X) __atomic_op_return{mb}(X,-,V)atomic_sub_return_relaxed(V,X) __atomic_op_return{once}(X,-,V)atomic_sub_return_acquire(V,X) __atomic_op_return{acquire}(X,-,V)atomic_sub_return_release(V,X) __atomic_op_return{release}(X,-,V)atomic_fetch_sub(V,X) __atomic_fetch_op{mb}(X,-,V)atomic_fetch_sub_relaxed(V,X) __atomic_fetch_op{once}(X,-,V)atomic_fetch_sub_acquire(V,X) __atomic_fetch_op{acquire}(X,-,V)atomic_fetch_sub_release(V,X) __atomic_fetch_op{release}(X,-,V) atomic_dec_return(X) __atomic_op_return{mb}(X,-,1)atomic_dec_return_relaxed(X) __atomic_op_return{once}(X,-,1)atomic_dec_return_acquire(X) __atomic_op_return{acquire}(X,-,1)atomic_dec_return_release(X) __atomic_op_return{release}(X,-,1)atomic_fetch_dec(X) __atomic_fetch_op{mb}(X,-,1)atomic_fetch_dec_relaxed(X) __atomic_fetch_op{once}(X,-,1)atomic_fetch_dec_acquire(X) __atomic_fetch_op{acquire}(X,-,1)atomic_fetch_dec_release(X) __atomic_fetch_op{release}(X,-,1) atomic_xchg(X,V) __xchg{mb}(X,V)atomic_xchg_relaxed(X,V) __xchg{once}(X,V)atomic_xchg_release(X,V) __xchg{release}(X,V)atomic_xchg_acquire(X,V) __xchg{acquire}(X,V)atomic_cmpxchg(X,V,W) __cmpxchg{mb}(X,V,W)atomic_cmpxchg_relaxed(X,V,W) __cmpxchg{once}(X,V,W)atomic_cmpxchg_acquire(X,V,W) __cmpxchg{acquire}(X,V,W)atomic_cmpxchg_release(X,V,W) __cmpxchg{release}(X,V,W) atomic_sub_and_test(V,X) __atomic_op_return{mb}(X,-,V) == 0atomic_dec_and_test(X)  __atomic_op_return{mb}(X,-,1) == 0atomic_inc_and_test(X)  __atomic_op_return{mb}(X,+,1) == 0atomic_add_negative(V,X) __atomic_op_return{mb}(X,+,V) < 0