// SPDX-License-Identifier: GPL-2.0+(* * Copyright (C) 2016 Luc Maranget <luc.maranget@inria.fr> for Inria * Copyright (C) 2017 Alan Stern <stern@rowland.harvard.edu> *) (* * Generate coherence orders and handle lock operations *) include "cross.cat" (* * The lock-related events generated by herd7 are as follows: * * LKR		Lock-Read: the read part of a spin_lock() or successful *			spin_trylock() read-modify-write event pair * LKW		Lock-Write: the write part of a spin_lock() or successful *			spin_trylock() RMW event pair * UL		Unlock: a spin_unlock() event * LF		Lock-Fail: a failed spin_trylock() event * RL		Read-Locked: a spin_is_locked() event which returns True * RU		Read-Unlocked: a spin_is_locked() event which returns False * * LKR and LKW events always come paired, like all RMW event sequences. * * LKR, LF, RL, and RU are read events; LKR has Acquire ordering. * LKW and UL are write events; UL has Release ordering. * LKW, LF, RL, and RU have no ordering properties. *) (* Backward compatibility *)let RL = try RL with emptysetlet RU = try RU with emptyset (* Treat RL as a kind of LF: a read with no ordering properties *)let LF = LF | RL (* There should be no ordinary R or W accesses to spinlocks *)let ALL-LOCKS = LKR | LKW | UL | LF | RUflag ~empty [M \ IW] ; loc ; [ALL-LOCKS] as mixed-lock-accesses (* Link Lock-Reads to their RMW-partner Lock-Writes *)let lk-rmw = ([LKR] ; po-loc ; [LKW]) \ (po ; po)let rmw = rmw | lk-rmw (* The litmus test is invalid if an LKR/LKW event is not part of an RMW pair *)flag ~empty LKW \ range(lk-rmw) as unpaired-LKWflag ~empty LKR \ domain(lk-rmw) as unpaired-LKR (* * An LKR must always see an unlocked value; spin_lock() calls nested * inside a critical section (for the same lock) always deadlock. *)empty ([LKW] ; po-loc ; [LKR]) \ (po-loc ; [UL] ; po-loc) as lock-nest (* The final value of a spinlock should not be tested *)flag ~empty [FW] ; loc ; [ALL-LOCKS] as lock-final (* * Put lock operations in their appropriate classes, but leave UL out of W * until after the co relation has been generated. *)let R = R | LKR | LF | RUlet W = W | LKW let Release = Release | ULlet Acquire = Acquire | LKR (* Match LKW events to their corresponding UL events *)let critical = ([LKW] ; po-loc ; [UL]) \ (po-loc ; [LKW | UL] ; po-loc) flag ~empty UL \ range(critical) as unmatched-unlock (* Allow up to one unmatched LKW per location; more must deadlock *)let UNMATCHED-LKW = LKW \ domain(critical)empty ([UNMATCHED-LKW] ; loc ; [UNMATCHED-LKW]) \ id as unmatched-locks (* rfi for LF events: link each LKW to the LF events in its critical section *)let rfi-lf = ([LKW] ; po-loc ; [LF]) \ ([LKW] ; po-loc ; [UL] ; po-loc) (* rfe for LF events *)let all-possible-rfe-lf =	(*	 * Given an LF event r, compute the possible rfe edges for that event	 * (all those starting from LKW events in other threads),	 * and then convert that relation to a set of single-edge relations.	 *)	let possible-rfe-lf r =		let pair-to-relation p = p ++ 0		in map pair-to-relation ((LKW * {r}) & loc & ext)	(* Do this for each LF event r that isn't in rfi-lf *)	in map possible-rfe-lf (LF \ range(rfi-lf)) (* Generate all rf relations for LF events *)with rfe-lf from cross(all-possible-rfe-lf)let rf-lf = rfe-lf | rfi-lf (* * RU, i.e., spin_is_locked() returning False, is slightly different. * We rely on the memory model to rule out cases where spin_is_locked() * within one of the lock's critical sections returns False. *) (* rfi for RU events: an RU may read from the last po-previous UL *)let rfi-ru = ([UL] ; po-loc ; [RU]) \ ([UL] ; po-loc ; [LKW] ; po-loc) (* rfe for RU events: an RU may read from an external UL or the initial write *)let all-possible-rfe-ru =	let possible-rfe-ru r =		let pair-to-relation p = p ++ 0		in map pair-to-relation (((UL | IW) * {r}) & loc & ext)	in map possible-rfe-ru RU (* Generate all rf relations for RU events *)with rfe-ru from cross(all-possible-rfe-ru)let rf-ru = rfe-ru | rfi-ru (* Final rf relation *)let rf = rf | rf-lf | rf-ru (* Generate all co relations, including LKW events but not UL *)let co0 = co0 | ([IW] ; loc ; [LKW]) |	(([LKW] ; loc ; [UNMATCHED-LKW]) \ [UNMATCHED-LKW])include "cos-opt.cat"let W = W | ULlet M = R | W (* Merge UL events into co *)let co = (co | critical | (critical^-1 ; co))+let coe = co & extlet coi = co & int (* Merge LKR events into rf *)let rf = rf | ([IW | UL] ; singlestep(co) ; lk-rmw^-1)let rfe = rf & extlet rfi = rf & int let fr = rf^-1 ; colet fre = fr & extlet fri = fr & int show co,rf,fr