1 /* SPDX-License-Identifier: GPL-2.0 */
2
3 /*
4 * Copyright (c) 2025, Google LLC.
5 * Pasha Tatashin <pasha.tatashin@soleen.com>
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
14 struct luo_ucmd {
15 void __user *ubuffer;
16 u32 user_size;
17 void *cmd;
18 };
19
luo_ucmd_respond(struct luo_ucmd * ucmd,size_t kernel_cmd_size)20 static inline int luo_ucmd_respond(struct luo_ucmd *ucmd,
21 size_t kernel_cmd_size)
22 {
23 /*
24 * Copy the minimum of what the user provided and what we actually
25 * have.
26 */
27 if (copy_to_user(ucmd->ubuffer, ucmd->cmd,
28 min_t(size_t, ucmd->user_size, kernel_cmd_size))) {
29 return -EFAULT;
30 }
31 return 0;
32 }
33
34 /*
35 * Handles a deserialization failure: devices and memory is in unpredictable
36 * state.
37 *
38 * Continuing the boot process after a failure is dangerous because it could
39 * lead to leaks of private data.
40 */
41 #define luo_restore_fail(__fmt, ...) panic(__fmt, ##__VA_ARGS__)
42
43 /* Mimics list_for_each_entry() but for private list head entries */
44 #define luo_list_for_each_private(pos, head, member) \
45 for (struct list_head *__iter = (head)->next; \
46 __iter != (head) && \
47 ({ pos = container_of(__iter, typeof(*(pos)), member); 1; }); \
48 __iter = __iter->next)
49
50 /**
51 * struct luo_file_set - A set of files that belong to the same sessions.
52 * @files_list: An ordered list of files associated with this session, it is
53 * ordered by preservation time.
54 * @files: The physically contiguous memory block that holds the serialized
55 * state of files.
56 * @count: A counter tracking the number of files currently stored in the
57 * @files_list for this session.
58 */
59 struct luo_file_set {
60 struct list_head files_list;
61 struct luo_file_ser *files;
62 long count;
63 };
64
65 /**
66 * struct luo_session - Represents an active or incoming Live Update session.
67 * @name: A unique name for this session, used for identification and
68 * retrieval.
69 * @ser: Pointer to the serialized data for this session.
70 * @list: A list_head member used to link this session into a global list
71 * of either outgoing (to be preserved) or incoming (restored from
72 * previous kernel) sessions.
73 * @retrieved: A boolean flag indicating whether this session has been
74 * retrieved by a consumer in the new kernel.
75 * @file_set: A set of files that belong to this session.
76 * @mutex: protects fields in the luo_session.
77 */
78 struct luo_session {
79 char name[LIVEUPDATE_SESSION_NAME_LENGTH];
80 struct luo_session_ser *ser;
81 struct list_head list;
82 bool retrieved;
83 struct luo_file_set file_set;
84 struct mutex mutex;
85 };
86
87 int luo_session_create(const char *name, struct file **filep);
88 int luo_session_retrieve(const char *name, struct file **filep);
89 int __init luo_session_setup_outgoing(void *fdt);
90 int __init luo_session_setup_incoming(void *fdt);
91 int luo_session_serialize(void);
92 int luo_session_deserialize(void);
93 bool luo_session_quiesce(void);
94 void luo_session_resume(void);
95
96 int luo_preserve_file(struct luo_file_set *file_set, u64 token, int fd);
97 void luo_file_unpreserve_files(struct luo_file_set *file_set);
98 int luo_file_freeze(struct luo_file_set *file_set,
99 struct luo_file_set_ser *file_set_ser);
100 void luo_file_unfreeze(struct luo_file_set *file_set,
101 struct luo_file_set_ser *file_set_ser);
102 int luo_retrieve_file(struct luo_file_set *file_set, u64 token,
103 struct file **filep);
104 int luo_file_finish(struct luo_file_set *file_set);
105 int luo_file_deserialize(struct luo_file_set *file_set,
106 struct luo_file_set_ser *file_set_ser);
107 void luo_file_set_init(struct luo_file_set *file_set);
108 void luo_file_set_destroy(struct luo_file_set *file_set);
109
110 #endif /* _LINUX_LUO_INTERNAL_H */
111