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1/* SPDX-License-Identifier: GPL-2.0 */
2
3/*
4 * Copyright (c) 2025, Google LLC.
5 * Pasha Tatashin <[email protected]>
6 */
7
8#ifndef _LINUX_LUO_INTERNAL_H
9#define _LINUX_LUO_INTERNAL_H
10
11#include <linux/liveupdate.h>
12#include <linux/uaccess.h>
13#include <linux/kho_block.h>
14
15struct luo_ucmd {
16 void __user *ubuffer;
17 u32 user_size;
18 void *cmd;
19};
20
21static inline int luo_ucmd_respond(struct luo_ucmd *ucmd,
22 size_t kernel_cmd_size)
23{
24 /*
25 * Copy the minimum of what the user provided and what we actually
26 * have.
27 */
28 if (copy_to_user(ucmd->ubuffer, ucmd->cmd,
29 min_t(size_t, ucmd->user_size, kernel_cmd_size))) {
30 return -EFAULT;
31 }
32 return 0;
33}
34
35/*
36 * Handles a deserialization failure: devices and memory is in unpredictable
37 * state.
38 *
39 * Continuing the boot process after a failure is dangerous because it could
40 * lead to leaks of private data.
41 */
42#define luo_restore_fail(__fmt, ...) panic(__fmt, ##__VA_ARGS__)
43
44/**
45 * struct luo_file_set - A set of files that belong to the same sessions.
46 * @files_list: An ordered list of files associated with this session, it is
47 * ordered by preservation time.
48 * @block_set: The set of serialization blocks.
49 * @count: A counter tracking the number of files currently stored in the
50 * @files_list for this session.
51 */
52struct luo_file_set {
53 struct list_head files_list;
54 struct kho_block_set block_set;
55 u64 count;
56};
57
58/**
59 * struct luo_session - Represents an active or incoming Live Update session.
60 * @name: A unique name for this session, used for identification and
61 * retrieval.
62 * @list: A list_head member used to link this session into a global list
63 * of either outgoing (to be preserved) or incoming (restored from
64 * previous kernel) sessions.
65 * @retrieved: A boolean flag indicating whether this session has been
66 * retrieved by a consumer in the new kernel.
67 * @file_set: A set of files that belong to this session.
68 * @mutex: protects fields in the luo_session.
69 */
70struct luo_session {
71 char name[LIVEUPDATE_SESSION_NAME_LENGTH];
72 struct list_head list;
73 bool retrieved;
74 struct luo_file_set file_set;
75 struct mutex mutex;
76};
77
78extern struct rw_semaphore luo_register_rwlock;
79
80int luo_session_create(const char *name, struct file **filep);
81int luo_session_retrieve(const char *name, struct file **filep);
82void __init luo_session_setup_outgoing(u64 *sessions_pa);
83int __init luo_session_setup_incoming(u64 sessions_pa);
84int luo_session_serialize(void);
85int luo_session_deserialize(void);
86
87int luo_preserve_file(struct luo_file_set *file_set, u64 token, int fd);
88void luo_file_unpreserve_files(struct luo_file_set *file_set);
89int luo_file_freeze(struct luo_file_set *file_set,
90 struct luo_file_set_ser *file_set_ser);
91void luo_file_unfreeze(struct luo_file_set *file_set,
92 struct luo_file_set_ser *file_set_ser);
93int luo_retrieve_file(struct luo_file_set *file_set, u64 token,
94 struct file **filep);
95int luo_file_finish(struct luo_file_set *file_set);
96int luo_file_deserialize(struct luo_file_set *file_set,
97 struct luo_file_set_ser *file_set_ser);
98void luo_file_set_init(struct luo_file_set *file_set);
99void luo_file_set_destroy(struct luo_file_set *file_set);
100
101int luo_flb_file_preserve(struct liveupdate_file_handler *fh);
102void luo_flb_file_unpreserve(struct liveupdate_file_handler *fh);
103void luo_flb_file_finish(struct liveupdate_file_handler *fh);
104void luo_flb_unregister_all(struct liveupdate_file_handler *fh);
105int __init luo_flb_setup_outgoing(u64 *flbs_pa);
106void __init luo_flb_setup_incoming(u64 flbs_pa);
107void luo_flb_serialize(void);
108
109#ifdef CONFIG_LIVEUPDATE_TEST
110void liveupdate_test_register(struct liveupdate_file_handler *fh);
111#else
112static inline void liveupdate_test_register(struct liveupdate_file_handler *fh) { }
113#endif
114
115#endif /* _LINUX_LUO_INTERNAL_H */