linux-stable/tools/memory-model/linux-kernel.def
Alan Stern a3f600d92d tools/memory-model: Add SRCU support
Add support for SRCU.  Herd creates srcu events and linux-kernel.def
associates them with three possible annotations (srcu-lock,
srcu-unlock, and sync-srcu) corresponding to the API routines
srcu_read_lock(), srcu_read_unlock(), and synchronize_srcu().

The linux-kernel.bell file now declares the annotations
and determines matching lock/unlock pairs delimiting SRCU read-side
critical sections, and it also checks for synchronize_srcu() calls
inside an RCU critical section (which would generate a "sleeping in
atomic context" error in real kernel code).  The linux-kernel.cat file
now adds SRCU-induced ordering, analogous to the existing RCU-induced
ordering, to the gp and rcu-fence relations.

Curiously enough, these small changes to the model's .cat code are all
that is needed to describe SRCU.

Portions of this patch (linux-kernel.def and the first hunk in
linux-kernel.bell) were written by Luc Maranget.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: Luc Maranget <luc.maranget@inria.fr>
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
Tested-by: Andrea Parri <andrea.parri@amarulasolutions.com>
2019-03-18 10:27:52 -07:00

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Modula-2

// 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.
// ONCE
READ_ONCE(X) __load{once}(X)
WRITE_ONCE(X,V) { __store{once}(X,V); }
// Release Acquire and friends
smp_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}; }
// Fences
smp_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}; }
// Exchange
xchg(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)
// Spinlocks
spin_lock(X) { __lock(X); }
spin_unlock(X) { __unlock(X); }
spin_trylock(X) __trylock(X)
spin_is_locked(X) __islocked(X)
// RCU
rcu_read_lock() { __fence{rcu-lock}; }
rcu_read_unlock() { __fence{rcu-unlock}; }
synchronize_rcu() { __fence{sync-rcu}; }
synchronize_rcu_expedited() { __fence{sync-rcu}; }
// SRCU
srcu_read_lock(X) __srcu{srcu-lock}(X)
srcu_read_unlock(X,Y) { __srcu{srcu-unlock}(X); }
synchronize_srcu(X) { __srcu{sync-srcu}(X); }
// Atomic
atomic_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) == 0
atomic_dec_and_test(X) __atomic_op_return{mb}(X,-,1) == 0
atomic_inc_and_test(X) __atomic_op_return{mb}(X,+,1) == 0
atomic_add_negative(V,X) __atomic_op_return{mb}(X,+,V) < 0