From 76cb841cb886eef6b3bee341a2266c76578724ad Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Mon, 6 May 2024 03:02:30 +0200 Subject: Adding upstream version 4.19.249. Signed-off-by: Daniel Baumann --- tools/memory-model/lock.cat | 146 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 146 insertions(+) create mode 100644 tools/memory-model/lock.cat (limited to 'tools/memory-model/lock.cat') diff --git a/tools/memory-model/lock.cat b/tools/memory-model/lock.cat new file mode 100644 index 000000000..305ded17e --- /dev/null +++ b/tools/memory-model/lock.cat @@ -0,0 +1,146 @@ +// SPDX-License-Identifier: GPL-2.0+ +(* + * Copyright (C) 2016 Luc Maranget for Inria + * Copyright (C) 2017 Alan Stern + *) + +(* + * Generate coherence orders and handle lock operations + * + * Warning: spin_is_locked() crashes herd7 versions strictly before 7.48. + * spin_is_locked() is functional from herd7 version 7.49. + *) + +include "cross.cat" + +(* + * The lock-related events generated by herd 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 emptyset +let 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 | RU +flag ~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-LKW +flag ~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 | RU +let W = W | LKW + +let Release = Release | UL +let 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 | UL +let M = R | W + +(* Merge UL events into co *) +let co = (co | critical | (critical^-1 ; co))+ +let coe = co & ext +let coi = co & int + +(* Merge LKR events into rf *) +let rf = rf | ([IW | UL] ; singlestep(co) ; lk-rmw^-1) +let rfe = rf & ext +let rfi = rf & int + +let fr = rf^-1 ; co +let fre = fr & ext +let fri = fr & int + +show co,rf,fr -- cgit v1.2.3