1 // SPDX-License-Identifier: GPL-2.0+ 1 // SPDX-License-Identifier: GPL-2.0+
2 (* 2 (*
3 * Copyright (C) 2016 Luc Maranget <luc.marange 3 * Copyright (C) 2016 Luc Maranget <luc.maranget@inria.fr> for Inria
4 * Copyright (C) 2017 Alan Stern <stern@rowland 4 * Copyright (C) 2017 Alan Stern <stern@rowland.harvard.edu>
5 *) 5 *)
6 6
7 (* 7 (*
8 * Generate coherence orders and handle lock o 8 * Generate coherence orders and handle lock operations
9 *) 9 *)
10 10
11 include "cross.cat" 11 include "cross.cat"
12 12
13 (* 13 (*
14 * The lock-related events generated by herd7 14 * The lock-related events generated by herd7 are as follows:
15 * 15 *
16 * LKR Lock-Read: the read part of a 16 * LKR Lock-Read: the read part of a spin_lock() or successful
17 * spin_trylock() read-mo 17 * spin_trylock() read-modify-write event pair
18 * LKW Lock-Write: the write part of 18 * LKW Lock-Write: the write part of a spin_lock() or successful
19 * spin_trylock() RMW eve 19 * spin_trylock() RMW event pair
20 * UL Unlock: a spin_unlock() event 20 * UL Unlock: a spin_unlock() event
21 * LF Lock-Fail: a failed spin_trylo 21 * LF Lock-Fail: a failed spin_trylock() event
22 * RL Read-Locked: a spin_is_locked( 22 * RL Read-Locked: a spin_is_locked() event which returns True
23 * RU Read-Unlocked: a spin_is_locke 23 * RU Read-Unlocked: a spin_is_locked() event which returns False
24 * 24 *
25 * LKR and LKW events always come paired, like 25 * LKR and LKW events always come paired, like all RMW event sequences.
26 * 26 *
27 * LKR, LF, RL, and RU are read events; LKR ha 27 * LKR, LF, RL, and RU are read events; LKR has Acquire ordering.
28 * LKW and UL are write events; UL has Release 28 * LKW and UL are write events; UL has Release ordering.
29 * LKW, LF, RL, and RU have no ordering proper 29 * LKW, LF, RL, and RU have no ordering properties.
30 *) 30 *)
31 31
32 (* Backward compatibility *) 32 (* Backward compatibility *)
33 let RL = try RL with emptyset 33 let RL = try RL with emptyset
34 let RU = try RU with emptyset 34 let RU = try RU with emptyset
35 35
36 (* Treat RL as a kind of LF: a read with no or 36 (* Treat RL as a kind of LF: a read with no ordering properties *)
37 let LF = LF | RL 37 let LF = LF | RL
38 38
39 (* There should be no ordinary R or W accesses 39 (* There should be no ordinary R or W accesses to spinlocks or SRCU structs *)
40 let ALL-LOCKS = LKR | LKW | UL | LF | RU | Src 40 let ALL-LOCKS = LKR | LKW | UL | LF | RU | Srcu-lock | Srcu-unlock | Sync-srcu
41 flag ~empty [M \ IW \ ALL-LOCKS] ; loc ; [ALL- 41 flag ~empty [M \ IW \ ALL-LOCKS] ; loc ; [ALL-LOCKS] as mixed-lock-accesses
42 42
43 (* Link Lock-Reads to their RMW-partner Lock-W 43 (* Link Lock-Reads to their RMW-partner Lock-Writes *)
44 let lk-rmw = ([LKR] ; po-loc ; [LKW]) \ (po ; 44 let lk-rmw = ([LKR] ; po-loc ; [LKW]) \ (po ; po)
45 let rmw = rmw | lk-rmw 45 let rmw = rmw | lk-rmw
46 46
47 (* The litmus test is invalid if an LKR/LKW ev 47 (* The litmus test is invalid if an LKR/LKW event is not part of an RMW pair *)
48 flag ~empty LKW \ range(lk-rmw) as unpaired-LK 48 flag ~empty LKW \ range(lk-rmw) as unpaired-LKW
49 flag ~empty LKR \ domain(lk-rmw) as unpaired-L 49 flag ~empty LKR \ domain(lk-rmw) as unpaired-LKR
50 50
51 (* 51 (*
52 * An LKR must always see an unlocked value; s 52 * An LKR must always see an unlocked value; spin_lock() calls nested
53 * inside a critical section (for the same loc 53 * inside a critical section (for the same lock) always deadlock.
54 *) 54 *)
55 empty ([LKW] ; po-loc ; [LKR]) \ (po-loc ; [UL 55 empty ([LKW] ; po-loc ; [LKR]) \ (po-loc ; [UL] ; po-loc) as lock-nest
56 56
57 (* 57 (*
58 * In the same way, spin_is_locked() inside a 58 * In the same way, spin_is_locked() inside a critical section must always
59 * return True (no RU events can be in a criti 59 * return True (no RU events can be in a critical section for the same lock).
60 *) 60 *)
61 empty ([LKW] ; po-loc ; [RU]) \ (po-loc ; [UL] 61 empty ([LKW] ; po-loc ; [RU]) \ (po-loc ; [UL] ; po-loc) as nested-is-locked
62 62
63 (* The final value of a spinlock should not be 63 (* The final value of a spinlock should not be tested *)
64 flag ~empty [FW] ; loc ; [ALL-LOCKS] as lock-f 64 flag ~empty [FW] ; loc ; [ALL-LOCKS] as lock-final
65 65
66 (* 66 (*
67 * Put lock operations in their appropriate cl 67 * Put lock operations in their appropriate classes, but leave UL out of W
68 * until after the co relation has been genera 68 * until after the co relation has been generated.
69 *) 69 *)
70 let R = R | LKR | LF | RU 70 let R = R | LKR | LF | RU
71 let W = W | LKW 71 let W = W | LKW
72 72
73 let Release = Release | UL 73 let Release = Release | UL
74 let Acquire = Acquire | LKR 74 let Acquire = Acquire | LKR
75 75
76 (* Match LKW events to their corresponding UL 76 (* Match LKW events to their corresponding UL events *)
77 let critical = ([LKW] ; po-loc ; [UL]) \ (po-l 77 let critical = ([LKW] ; po-loc ; [UL]) \ (po-loc ; [LKW | UL] ; po-loc)
78 78
79 flag ~empty UL \ range(critical) as unmatched- 79 flag ~empty UL \ range(critical) as unmatched-unlock
80 80
81 (* Allow up to one unmatched LKW per location; 81 (* Allow up to one unmatched LKW per location; more must deadlock *)
82 let UNMATCHED-LKW = LKW \ domain(critical) 82 let UNMATCHED-LKW = LKW \ domain(critical)
83 empty ([UNMATCHED-LKW] ; loc ; [UNMATCHED-LKW] 83 empty ([UNMATCHED-LKW] ; loc ; [UNMATCHED-LKW]) \ id as unmatched-locks
84 84
85 (* rfi for LF events: link each LKW to the LF 85 (* rfi for LF events: link each LKW to the LF events in its critical section *)
86 let rfi-lf = ([LKW] ; po-loc ; [LF]) \ ([LKW] 86 let rfi-lf = ([LKW] ; po-loc ; [LF]) \ ([LKW] ; po-loc ; [UL] ; po-loc)
87 87
88 (* Utility macro to convert a single pair to a 88 (* Utility macro to convert a single pair to a single-edge relation *)
89 let pair-to-relation p = p ++ 0 89 let pair-to-relation p = p ++ 0
90 90
91 (* 91 (*
92 * If a given LF event e is outside a critical 92 * If a given LF event e is outside a critical section, it cannot read
93 * internally but it may read from an LKW even 93 * internally but it may read from an LKW event in another thread.
94 * Compute the relation containing these possi 94 * Compute the relation containing these possible edges.
95 *) 95 *)
96 let possible-rfe-noncrit-lf e = (LKW * {e}) & 96 let possible-rfe-noncrit-lf e = (LKW * {e}) & loc & ext
97 97
98 (* Compute set of sets of possible rfe edges f 98 (* Compute set of sets of possible rfe edges for LF events *)
99 let all-possible-rfe-lf = 99 let all-possible-rfe-lf =
100 (* 100 (*
101 * Convert the possible-rfe-noncrit-lf 101 * Convert the possible-rfe-noncrit-lf relation for e
102 * to a set of single edges 102 * to a set of single edges
103 *) 103 *)
104 let set-of-singleton-rfe-lf e = 104 let set-of-singleton-rfe-lf e =
105 map pair-to-relation ( 105 map pair-to-relation (possible-rfe-noncrit-lf e)
106 (* Do this for each LF event e that is 106 (* Do this for each LF event e that isn't in rfi-lf *)
107 in map set-of-singleton-rfe-lf (LF \ r 107 in map set-of-singleton-rfe-lf (LF \ range(rfi-lf))
108 108
109 (* Generate all rf relations for LF events *) 109 (* Generate all rf relations for LF events *)
110 with rfe-lf from cross(all-possible-rfe-lf) 110 with rfe-lf from cross(all-possible-rfe-lf)
111 let rf-lf = rfe-lf | rfi-lf 111 let rf-lf = rfe-lf | rfi-lf
112 112
113 (* 113 (*
114 * A given RU event e may read internally from 114 * A given RU event e may read internally from the last po-previous UL,
115 * or it may read from a UL event in another t 115 * or it may read from a UL event in another thread or the initial write.
116 * Compute the relation containing these possi 116 * Compute the relation containing these possible edges.
117 *) 117 *)
118 let possible-rf-ru e = (((UL * {e}) & po-loc) 118 let possible-rf-ru e = (((UL * {e}) & po-loc) \
119 ([UL] ; po-loc ; [UL] 119 ([UL] ; po-loc ; [UL] ; po-loc)) |
120 (((UL | IW) * {e}) & loc & ext 120 (((UL | IW) * {e}) & loc & ext)
121 121
122 (* Compute set of sets of possible rf edges fo 122 (* Compute set of sets of possible rf edges for RU events *)
123 let all-possible-rf-ru = 123 let all-possible-rf-ru =
124 (* Convert the possible-rf-ru relation 124 (* Convert the possible-rf-ru relation for e to a set of single edges *)
125 let set-of-singleton-rf-ru e = 125 let set-of-singleton-rf-ru e =
126 map pair-to-relation (possible 126 map pair-to-relation (possible-rf-ru e)
127 (* Do this for each RU event e *) 127 (* Do this for each RU event e *)
128 in map set-of-singleton-rf-ru RU 128 in map set-of-singleton-rf-ru RU
129 129
130 (* Generate all rf relations for RU events *) 130 (* Generate all rf relations for RU events *)
131 with rf-ru from cross(all-possible-rf-ru) 131 with rf-ru from cross(all-possible-rf-ru)
132 132
133 (* Final rf relation *) 133 (* Final rf relation *)
134 let rf = rf | rf-lf | rf-ru 134 let rf = rf | rf-lf | rf-ru
135 135
136 (* Generate all co relations, including LKW ev 136 (* Generate all co relations, including LKW events but not UL *)
137 let co0 = co0 | ([IW] ; loc ; [LKW]) | 137 let co0 = co0 | ([IW] ; loc ; [LKW]) |
138 (([LKW] ; loc ; [UNMATCHED-LKW]) \ [UN 138 (([LKW] ; loc ; [UNMATCHED-LKW]) \ [UNMATCHED-LKW])
139 include "cos-opt.cat" 139 include "cos-opt.cat"
140 let W = W | UL 140 let W = W | UL
141 let M = R | W 141 let M = R | W
142 142
143 (* Merge UL events into co *) 143 (* Merge UL events into co *)
144 let co = (co | critical | (critical^-1 ; co))+ 144 let co = (co | critical | (critical^-1 ; co))+
145 let coe = co & ext 145 let coe = co & ext
146 let coi = co & int 146 let coi = co & int
147 147
148 (* Merge LKR events into rf *) 148 (* Merge LKR events into rf *)
149 let rf = rf | ([IW | UL] ; singlestep(co) ; lk 149 let rf = rf | ([IW | UL] ; singlestep(co) ; lk-rmw^-1)
150 let rfe = rf & ext 150 let rfe = rf & ext
151 let rfi = rf & int 151 let rfi = rf & int
152 152
153 let fr = rf^-1 ; co 153 let fr = rf^-1 ; co
154 let fre = fr & ext 154 let fre = fr & ext
155 let fri = fr & int 155 let fri = fr & int
156 156
157 show co,rf,fr 157 show co,rf,fr
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