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authorLinus Torvalds <torvalds@linux-foundation.org>2026-08-23 13:28:57 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2026-08-23 13:28:57 -0700
commit4352b8aee98005853aa63f57d6377282de17a33f (patch)
tree27614d7a9ef05c32d089004e104364ce42324837 /tools/memory-model/linux-kernel.cat
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Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linuxgrafted
Pull I3C updates from Alexandre Belloni: "A new driver this cycle, for the AMD AXI I3C controller. There are also new features such as IBI wakeup support, SETAASA device discovery and ACPI support for the the DAA methods, meaning we can now communicate with the SPD devices on DDR5 modules. New driver: - AMD AXI I3C master controller Subsystem: - I3C Common Command Code (CCC) handling improvements, especially around GET CCCs - SETAASA device discovery support - ACPI support for all existing DAA methods like SETDASA, SETNEWDA as well as I2C devices on I3C bus - IBI-based wakeup support Drivers: - dw: SETAASA support - mipi-i3c-hci: advertise IBI wakeup capability, AMD_PT I3C controller support, PIO queue management support for HCI v1.2 - renesas: improve suspend to RAM support, add runtime PM support" * tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux: (70 commits) i3c: dw: reduce do_daa time if there's no client i3c: mipi-i3c-hci: Add support for AMD_PT I3C controller i3c: mipi-i3c-hci: Add PIO queue management support for HCI v1.2 i3c: mipi-i3c-hci: Fix missing STAT_IBI_STATUS_THLD in PIO mode i3c: dw: rename "pclk" to "apb" to match dt-binding i3c: dw: make struct dw_i3c_cmd smaller i3c: dw: use COMMAND_PORT_TRANSFER_ARG instead of hardcoding i3c: renesas: Don't register devices when ENTDAA times out i3c: master: dw-i3c-master: fix OD timing for first broadcast i3c: mipi-i3c-hci: Advertise IBI wakeup capability i3c: mipi-i3c-hci: Factor out i3c_hci_sysdev() i3c: mipi-i3c-hci-pci: Propagate I3C wakeup requirements to PCI i3c: master: Reject IBI requests from non-IBI-capable devices i3c: master: Add helper to query bus wakeup requirements i3c: master: Report wakeup events for IBIs i3c: master: Support IBI-based wakeup capability i3c: master: Fix potential UAF in i3c_device_match() i3c: master: Fix potential UAF in i3c_device_uevent() i3c: Make dev->desc locking assumptions explicit i3c: master: Fix use-after-free of master->this ...
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+// SPDX-License-Identifier: GPL-2.0+
+(*
+ * Copyright (C) 2015 Jade Alglave <j.alglave@ucl.ac.uk>,
+ * Copyright (C) 2016 Luc Maranget <luc.maranget@inria.fr> for Inria
+ * Copyright (C) 2017 Alan Stern <stern@rowland.harvard.edu>,
+ * Andrea Parri <parri.andrea@gmail.com>
+ *
+ * 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.
+ *)
+
+"Linux-kernel memory consistency model"
+
+(*
+ * File "lock.cat" handles locks and is experimental.
+ * It can be replaced by include "cos.cat" for tests that do not use locks.
+ *)
+
+include "lock.cat"
+
+(*******************)
+(* Basic relations *)
+(*******************)
+
+(* Release Acquire *)
+let acq-po = [Acquire] ; po ; [M]
+let po-rel = [M] ; po ; [Release]
+let po-unlock-lock-po = po ; [UL] ; (po|rf) ; [LKR] ; po
+
+(* Fences *)
+let R4rmb = R \ Noreturn (* Reads for which rmb works *)
+let rmb = [R4rmb] ; fencerel(Rmb) ; [R4rmb]
+let wmb = [W] ; fencerel(Wmb) ; [W]
+let mb = ([M] ; fencerel(Mb) ; [M]) |
+ (*
+ * full-barrier RMWs (successful cmpxchg(), xchg(), etc.) act as
+ * though there were enclosed by smp_mb().
+ * The effect of these virtual smp_mb() is formalized by adding
+ * Mb tags to the read and write of the operation, and providing
+ * the same ordering as though there were additional po edges
+ * between the Mb tag and the read resp. write.
+ *)
+ ([M] ; po ; [Mb & R]) |
+ ([Mb & W] ; po ; [M]) |
+ ([M] ; fencerel(Before-atomic) ; [RMW] ; po? ; [M]) |
+ ([M] ; po? ; [RMW] ; fencerel(After-atomic) ; [M]) |
+ ([M] ; po? ; [LKW] ; fencerel(After-spinlock) ; [M]) |
+(*
+ * Note: The po-unlock-lock-po relation only passes the lock to the direct
+ * successor, perhaps giving the impression that the ordering of the
+ * smp_mb__after_unlock_lock() fence only affects a single lock handover.
+ * However, in a longer sequence of lock handovers, the implicit
+ * A-cumulative release fences of lock-release ensure that any stores that
+ * propagate to one of the involved CPUs before it hands over the lock to
+ * the next CPU will also propagate to the final CPU handing over the lock
+ * to the CPU that executes the fence. Therefore, all those stores are
+ * also affected by the fence.
+ *)
+ ([M] ; po-unlock-lock-po ;
+ [After-unlock-lock] ; po ; [M]) |
+ ([M] ; po? ; [Srcu-unlock] ; fencerel(After-srcu-read-unlock) ; [M])
+let gp = po ; [Sync-rcu | Sync-srcu] ; po?
+let strong-fence = mb | gp
+
+let nonrw-fence = strong-fence | po-rel | acq-po
+let fence = nonrw-fence | wmb | rmb
+let barrier = fencerel(Barrier | Rmb | Wmb | Mb | Sync-rcu | Sync-srcu |
+ Before-atomic | After-atomic | Acquire | Release |
+ Rcu-lock | Rcu-unlock | Srcu-lock | Srcu-unlock) |
+ (po ; [Release]) | ([Acquire] ; po)
+
+(**********************************)
+(* Fundamental coherence ordering *)
+(**********************************)
+
+(* Sequential Consistency Per Variable *)
+let com = rf | co | fr
+acyclic po-loc | com as coherence
+
+(* Atomic Read-Modify-Write *)
+empty rmw & (fre ; coe) as atomic
+
+(**********************************)
+(* Instruction execution ordering *)
+(**********************************)
+
+(* Preserved Program Order *)
+let dep = addr | data
+let rwdep = (dep | ctrl) ; [W]
+let overwrite = co | fr
+let to-w = rwdep | (overwrite & int) | (addr ; [Plain] ; wmb)
+let to-r = (addr ; [R]) | (dep ; [Marked] ; rfi)
+let ppo = to-r | to-w | (fence & int) | (po-unlock-lock-po & int)
+
+(* Propagation: Ordering from release operations and strong fences. *)
+let A-cumul(r) = (rfe ; [Marked])? ; r
+let rmw-sequence = (rf ; rmw)*
+let cumul-fence = [Marked] ; (A-cumul(strong-fence | po-rel) | wmb |
+ po-unlock-lock-po) ; [Marked] ; rmw-sequence
+let prop = [Marked] ; (overwrite & ext)? ; cumul-fence* ;
+ [Marked] ; rfe? ; [Marked]
+
+(*
+ * Happens Before: Ordering from the passage of time.
+ * No fences needed here for prop because relation confined to one process.
+ *)
+let hb = [Marked] ; (ppo | rfe | ((prop \ id) & int)) ; [Marked]
+acyclic hb as happens-before
+
+(****************************************)
+(* Write and fence propagation ordering *)
+(****************************************)
+
+(* Propagation: Each non-rf link needs a strong fence. *)
+let pb = prop ; strong-fence ; hb* ; [Marked]
+acyclic pb as propagation
+
+(*******)
+(* RCU *)
+(*******)
+
+(*
+ * Effects of read-side critical sections proceed from the rcu_read_unlock()
+ * or srcu_read_unlock() backwards on the one hand, and from the
+ * rcu_read_lock() or srcu_read_lock() forwards on the other hand.
+ *
+ * In the definition of rcu-fence below, the po term at the left-hand side
+ * of each disjunct and the po? term at the right-hand end have been factored
+ * out. They have been moved into the definitions of rcu-link and rb.
+ * This was necessary in order to apply the "& loc" tests correctly.
+ *)
+let rcu-gp = [Sync-rcu] (* Compare with gp *)
+let srcu-gp = [Sync-srcu]
+let rcu-rscsi = rcu-rscs^-1
+let srcu-rscsi = srcu-rscs^-1
+
+(*
+ * The synchronize_rcu() strong fence is special in that it can order not
+ * one but two non-rf relations, but only in conjunction with an RCU
+ * read-side critical section.
+ *)
+let rcu-link = po? ; hb* ; pb* ; prop ; po
+
+(*
+ * Any sequence containing at least as many grace periods as RCU read-side
+ * critical sections (joined by rcu-link) induces order like a generalized
+ * inter-CPU strong fence.
+ * Likewise for SRCU grace periods and read-side critical sections, provided
+ * the synchronize_srcu() and srcu_read_[un]lock() calls refer to the same
+ * struct srcu_struct location.
+ *)
+let rec rcu-order = rcu-gp | srcu-gp |
+ (rcu-gp ; rcu-link ; rcu-rscsi) |
+ ((srcu-gp ; rcu-link ; srcu-rscsi) & loc) |
+ (rcu-rscsi ; rcu-link ; rcu-gp) |
+ ((srcu-rscsi ; rcu-link ; srcu-gp) & loc) |
+ (rcu-gp ; rcu-link ; rcu-order ; rcu-link ; rcu-rscsi) |
+ ((srcu-gp ; rcu-link ; rcu-order ; rcu-link ; srcu-rscsi) & loc) |
+ (rcu-rscsi ; rcu-link ; rcu-order ; rcu-link ; rcu-gp) |
+ ((srcu-rscsi ; rcu-link ; rcu-order ; rcu-link ; srcu-gp) & loc) |
+ (rcu-order ; rcu-link ; rcu-order)
+let rcu-fence = po ; rcu-order ; po?
+let fence = fence | rcu-fence
+let strong-fence = strong-fence | rcu-fence
+
+(* rb orders instructions just as pb does *)
+let rb = prop ; rcu-fence ; hb* ; pb* ; [Marked]
+
+irreflexive rb as rcu
+
+(*
+ * The happens-before, propagation, and rcu constraints are all
+ * expressions of temporal ordering. They could be replaced by
+ * a single constraint on an "executes-before" relation, xb:
+ *
+ * let xb = hb | pb | rb
+ * acyclic xb as executes-before
+ *)
+
+(*********************************)
+(* Plain accesses and data races *)
+(*********************************)
+
+(* Warn about plain writes and marked accesses in the same region *)
+let mixed-accesses = ([Plain & W] ; (po-loc \ barrier) ; [Marked]) |
+ ([Marked] ; (po-loc \ barrier) ; [Plain & W])
+flag ~empty mixed-accesses as mixed-accesses
+
+(* Executes-before and visibility *)
+let xbstar = (hb | pb | rb)*
+let vis = cumul-fence* ; rfe? ; [Marked] ;
+ ((strong-fence ; [Marked] ; xbstar) | (xbstar & int))
+
+(* Boundaries for lifetimes of plain accesses *)
+let w-pre-bounded = [Marked] ; (addr | fence)?
+let r-pre-bounded = [Marked] ; (addr | nonrw-fence |
+ ([R4rmb] ; fencerel(Rmb) ; [~Noreturn]))?
+let w-post-bounded = fence? ; [Marked] ; rmw-sequence
+let r-post-bounded = (nonrw-fence | ([~Noreturn] ; fencerel(Rmb) ; [R4rmb]))? ;
+ [Marked]
+
+(* Visibility and executes-before for plain accesses *)
+let ww-vis = fence | (strong-fence ; xbstar ; w-pre-bounded) |
+ (w-post-bounded ; vis ; w-pre-bounded)
+let wr-vis = fence | (strong-fence ; xbstar ; r-pre-bounded) |
+ (w-post-bounded ; vis ; r-pre-bounded)
+let rw-xbstar = fence | (r-post-bounded ; xbstar ; w-pre-bounded)
+
+(* Potential races *)
+let pre-race = ext & ((Plain * M) | ((M \ IW) * Plain))
+
+(* Coherence requirements for plain accesses *)
+let wr-incoh = pre-race & rf & rw-xbstar^-1
+let rw-incoh = pre-race & fr & wr-vis^-1
+let ww-incoh = pre-race & co & ww-vis^-1
+empty (wr-incoh | rw-incoh | ww-incoh) as plain-coherence
+
+(* Actual races *)
+let ww-nonrace = ww-vis & ((Marked * W) | rw-xbstar) & ((W * Marked) | wr-vis)
+let ww-race = (pre-race & co) \ ww-nonrace
+let wr-race = (pre-race & (co? ; rf)) \ wr-vis \ rw-xbstar^-1
+let rw-race = (pre-race & fr) \ rw-xbstar
+
+flag ~empty (ww-race | wr-race | rw-race) as data-race