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1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _LINUX_RSEQ_TYPES_H
3#define _LINUX_RSEQ_TYPES_H
4
5#include <linux/irq_work_types.h>
6#include <linux/types.h>
7#include <linux/workqueue_types.h>
8
9#ifdef CONFIG_RSEQ
10struct rseq;
11
12/**
13 * struct rseq_event - Storage for rseq related event management
14 * @all: Compound to initialize and clear the data efficiently
15 * @events: Compound to access events with a single load/store
16 * @sched_switch: True if the task was scheduled and needs update on
17 * exit to user
18 * @ids_changed: Indicator that IDs need to be updated
19 * @user_irq: True on interrupt entry from user mode
20 * @has_rseq: True if the task has a rseq pointer installed
21 * @error: Compound error code for the slow path to analyze
22 * @fatal: User space data corrupted or invalid
23 * @slowpath: Indicator that slow path processing via TIF_NOTIFY_RESUME
24 * is required
25 *
26 * @sched_switch and @ids_changed must be adjacent and the combo must be
27 * 16bit aligned to allow a single store, when both are set at the same
28 * time in the scheduler.
29 */
30struct rseq_event {
31 union {
32 u64 all;
33 struct {
34 union {
35 u32 events;
36 struct {
37 u8 sched_switch;
38 u8 ids_changed;
39 u8 user_irq;
40 };
41 };
42
43 u8 has_rseq;
44 u8 __pad;
45 union {
46 u16 error;
47 struct {
48 u8 fatal;
49 u8 slowpath;
50 };
51 };
52 };
53 };
54};
55
56/**
57 * struct rseq_ids - Cache for ids, which need to be updated
58 * @cpu_cid: Compound of @cpu_id and @mm_cid to make the
59 * compiler emit a single compare on 64-bit
60 * @cpu_id: The CPU ID which was written last to user space
61 * @mm_cid: The MM CID which was written last to user space
62 *
63 * @cpu_id and @mm_cid are updated when the data is written to user space.
64 */
65struct rseq_ids {
66 union {
67 u64 cpu_cid;
68 struct {
69 u32 cpu_id;
70 u32 mm_cid;
71 };
72 };
73};
74
75/**
76 * struct rseq_data - Storage for all rseq related data
77 * @usrptr: Pointer to the registered user space RSEQ memory
78 * @len: Length of the RSEQ region
79 * @sig: Signature of critial section abort IPs
80 * @event: Storage for event management
81 * @ids: Storage for cached CPU ID and MM CID
82 */
83struct rseq_data {
84 struct rseq __user *usrptr;
85 u32 len;
86 u32 sig;
87 struct rseq_event event;
88 struct rseq_ids ids;
89};
90
91#else /* CONFIG_RSEQ */
92struct rseq_data { };
93#endif /* !CONFIG_RSEQ */
94
95#ifdef CONFIG_SCHED_MM_CID
96
97#define MM_CID_UNSET BIT(31)
98#define MM_CID_ONCPU BIT(30)
99#define MM_CID_TRANSIT BIT(29)
100
101/**
102 * struct sched_mm_cid - Storage for per task MM CID data
103 * @active: MM CID is active for the task
104 * @cid: The CID associated to the task either permanently or
105 * borrowed from the CPU
106 */
107struct sched_mm_cid {
108 unsigned int active;
109 unsigned int cid;
110};
111
112/**
113 * struct mm_cid_pcpu - Storage for per CPU MM_CID data
114 * @cid: The CID associated to the CPU either permanently or
115 * while a task with a CID is running
116 */
117struct mm_cid_pcpu {
118 unsigned int cid;
119}____cacheline_aligned_in_smp;
120
121/**
122 * struct mm_mm_cid - Storage for per MM CID data
123 * @pcpu: Per CPU storage for CIDs associated to a CPU
124 * @percpu: Set, when CIDs are in per CPU mode
125 * @transit: Set to MM_CID_TRANSIT during a mode change transition phase
126 * @max_cids: The exclusive maximum CID value for allocation and convergence
127 * @irq_work: irq_work to handle the affinity mode change case
128 * @work: Regular work to handle the affinity mode change case
129 * @lock: Spinlock to protect against affinity setting which can't take @mutex
130 * @mutex: Mutex to serialize forks and exits related to this mm
131 * @nr_cpus_allowed: The number of CPUs in the per MM allowed CPUs map. The map
132 * is growth only.
133 * @users: The number of tasks sharing this MM. Separate from mm::mm_users
134 * as that is modified by mmget()/mm_put() by other entities which
135 * do not actually share the MM.
136 * @pcpu_thrs: Threshold for switching back from per CPU mode
137 * @update_deferred: A deferred switch back to per task mode is pending.
138 */
139struct mm_mm_cid {
140 /* Hotpath read mostly members */
141 struct mm_cid_pcpu __percpu *pcpu;
142 unsigned int percpu;
143 unsigned int transit;
144 unsigned int max_cids;
145
146 /* Rarely used. Moves @lock and @mutex into the second cacheline */
147 struct irq_work irq_work;
148 struct work_struct work;
149
150 raw_spinlock_t lock;
151 struct mutex mutex;
152
153 /* Low frequency modified */
154 unsigned int nr_cpus_allowed;
155 unsigned int users;
156 unsigned int pcpu_thrs;
157 unsigned int update_deferred;
158}____cacheline_aligned_in_smp;
159#else /* CONFIG_SCHED_MM_CID */
160struct mm_mm_cid { };
161struct sched_mm_cid { };
162#endif /* !CONFIG_SCHED_MM_CID */
163
164#endif