tools/memory-model/linux-kernel.def

   1 // SPDX-License-Identifier: GPL-2.0+
   2 //
   3 // An earlier version of this file appeared in the companion webpage for
   4 // "Frightening small children and disconcerting grown-ups: Concurrency
   5 // in the Linux kernel" by Alglave, Maranget, McKenney, Parri, and Stern,
   6 // which appeared in ASPLOS 2018.
   7
   8 // ONCE
   9 READ_ONCE(X) __load{once}(X)
  10 WRITE_ONCE(X,V) { __store{once}(X,V); }
  11
  12 // Release Acquire and friends
  13 smp_store_release(X,V) { __store{release}(*X,V); }
  14 smp_load_acquire(X) __load{acquire}(*X)
  15 rcu_assign_pointer(X,V) { __store{release}(X,V); }
  16 rcu_dereference(X) __load{once}(X)
  17 smp_store_mb(X,V) { __store{once}(X,V); __fence{mb}; }
  18
  19 // Fences
  20 smp_mb() { __fence{mb}; }
  21 smp_rmb() { __fence{rmb}; }
  22 smp_wmb() { __fence{wmb}; }
  23 smp_mb__before_atomic() { __fence{before-atomic}; }
  24 smp_mb__after_atomic() { __fence{after-atomic}; }
  25 smp_mb__after_spinlock() { __fence{after-spinlock}; }
  26 smp_mb__after_unlock_lock() { __fence{after-unlock-lock}; }
  27 smp_mb__after_srcu_read_unlock() { __fence{after-srcu-read-unlock}; }
  28 barrier() { __fence{barrier}; }
  29
  30 // Exchange
  31 xchg(X,V)  __xchg{mb}(X,V)
  32 xchg_relaxed(X,V) __xchg{once}(X,V)
  33 xchg_release(X,V) __xchg{release}(X,V)
  34 xchg_acquire(X,V) __xchg{acquire}(X,V)
  35 cmpxchg(X,V,W) __cmpxchg{mb}(X,V,W)
  36 cmpxchg_relaxed(X,V,W) __cmpxchg{once}(X,V,W)
  37 cmpxchg_acquire(X,V,W) __cmpxchg{acquire}(X,V,W)
  38 cmpxchg_release(X,V,W) __cmpxchg{release}(X,V,W)
  39
  40 // Spinlocks
  41 spin_lock(X) { __lock(X); }
  42 spin_unlock(X) { __unlock(X); }
  43 spin_trylock(X) __trylock(X)
  44 spin_is_locked(X) __islocked(X)
  45
  46 // RCU
  47 rcu_read_lock() { __fence{rcu-lock}; }
  48 rcu_read_unlock() { __fence{rcu-unlock}; }
  49 synchronize_rcu() { __fence{sync-rcu}; }
  50 synchronize_rcu_expedited() { __fence{sync-rcu}; }
  51
  52 // SRCU
  53 srcu_read_lock(X) __load{srcu-lock}(*X)
  54 srcu_read_unlock(X,Y) { __store{srcu-unlock}(*X,Y); }
  55 srcu_down_read(X) __load{srcu-lock}(*X)
  56 srcu_up_read(X,Y) { __store{srcu-unlock}(*X,Y); }
  57 synchronize_srcu(X)  { __srcu{sync-srcu}(X); }
  58 synchronize_srcu_expedited(X)  { __srcu{sync-srcu}(X); }
  59
  60 // Atomic
  61 atomic_read(X) READ_ONCE(*X)
  62 atomic_set(X,V) { WRITE_ONCE(*X,V); }
  63 atomic_read_acquire(X) smp_load_acquire(X)
  64 atomic_set_release(X,V) { smp_store_release(X,V); }
  65
  66 atomic_add(V,X) { __atomic_op(X,+,V); }
  67 atomic_sub(V,X) { __atomic_op(X,-,V); }
  68 atomic_inc(X)   { __atomic_op(X,+,1); }
  69 atomic_dec(X)   { __atomic_op(X,-,1); }
  70
  71 atomic_add_return(V,X) __atomic_op_return{mb}(X,+,V)
  72 atomic_add_return_relaxed(V,X) __atomic_op_return{once}(X,+,V)
  73 atomic_add_return_acquire(V,X) __atomic_op_return{acquire}(X,+,V)
  74 atomic_add_return_release(V,X) __atomic_op_return{release}(X,+,V)
  75 atomic_fetch_add(V,X) __atomic_fetch_op{mb}(X,+,V)
  76 atomic_fetch_add_relaxed(V,X) __atomic_fetch_op{once}(X,+,V)
  77 atomic_fetch_add_acquire(V,X) __atomic_fetch_op{acquire}(X,+,V)
  78 atomic_fetch_add_release(V,X) __atomic_fetch_op{release}(X,+,V)
  79
  80 atomic_inc_return(X) __atomic_op_return{mb}(X,+,1)
  81 atomic_inc_return_relaxed(X) __atomic_op_return{once}(X,+,1)
  82 atomic_inc_return_acquire(X) __atomic_op_return{acquire}(X,+,1)
  83 atomic_inc_return_release(X) __atomic_op_return{release}(X,+,1)
  84 atomic_fetch_inc(X) __atomic_fetch_op{mb}(X,+,1)
  85 atomic_fetch_inc_relaxed(X) __atomic_fetch_op{once}(X,+,1)
  86 atomic_fetch_inc_acquire(X) __atomic_fetch_op{acquire}(X,+,1)
  87 atomic_fetch_inc_release(X) __atomic_fetch_op{release}(X,+,1)
  88
  89 atomic_sub_return(V,X) __atomic_op_return{mb}(X,-,V)
  90 atomic_sub_return_relaxed(V,X) __atomic_op_return{once}(X,-,V)
  91 atomic_sub_return_acquire(V,X) __atomic_op_return{acquire}(X,-,V)
  92 atomic_sub_return_release(V,X) __atomic_op_return{release}(X,-,V)
  93 atomic_fetch_sub(V,X) __atomic_fetch_op{mb}(X,-,V)
  94 atomic_fetch_sub_relaxed(V,X) __atomic_fetch_op{once}(X,-,V)
  95 atomic_fetch_sub_acquire(V,X) __atomic_fetch_op{acquire}(X,-,V)
  96 atomic_fetch_sub_release(V,X) __atomic_fetch_op{release}(X,-,V)
  97
  98 atomic_dec_return(X) __atomic_op_return{mb}(X,-,1)
  99 atomic_dec_return_relaxed(X) __atomic_op_return{once}(X,-,1)
 100 atomic_dec_return_acquire(X) __atomic_op_return{acquire}(X,-,1)
 101 atomic_dec_return_release(X) __atomic_op_return{release}(X,-,1)
 102 atomic_fetch_dec(X) __atomic_fetch_op{mb}(X,-,1)
 103 atomic_fetch_dec_relaxed(X) __atomic_fetch_op{once}(X,-,1)
 104 atomic_fetch_dec_acquire(X) __atomic_fetch_op{acquire}(X,-,1)
 105 atomic_fetch_dec_release(X) __atomic_fetch_op{release}(X,-,1)
 106
 107 atomic_xchg(X,V) __xchg{mb}(X,V)
 108 atomic_xchg_relaxed(X,V) __xchg{once}(X,V)
 109 atomic_xchg_release(X,V) __xchg{release}(X,V)
 110 atomic_xchg_acquire(X,V) __xchg{acquire}(X,V)
 111 atomic_cmpxchg(X,V,W) __cmpxchg{mb}(X,V,W)
 112 atomic_cmpxchg_relaxed(X,V,W) __cmpxchg{once}(X,V,W)
 113 atomic_cmpxchg_acquire(X,V,W) __cmpxchg{acquire}(X,V,W)
 114 atomic_cmpxchg_release(X,V,W) __cmpxchg{release}(X,V,W)
 115
 116 atomic_sub_and_test(V,X) __atomic_op_return{mb}(X,-,V) == 0
 117 atomic_dec_and_test(X)  __atomic_op_return{mb}(X,-,1) == 0
 118 atomic_inc_and_test(X)  __atomic_op_return{mb}(X,+,1) == 0
 119 atomic_add_negative(V,X) __atomic_op_return{mb}(X,+,V) < 0