luo_internal.h

  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
 14struct luo_ucmd {
 15	void __user *ubuffer;
 16	u32 user_size;
 17	void *cmd;
 18};
 19
 20static 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 */
 59struct 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 */
 78struct 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
 87int luo_session_create(const char *name, struct file **filep);
 88int luo_session_retrieve(const char *name, struct file **filep);
 89int __init luo_session_setup_outgoing(void *fdt);
 90int __init luo_session_setup_incoming(void *fdt);
 91int luo_session_serialize(void);
 92int luo_session_deserialize(void);
 93bool luo_session_quiesce(void);
 94void luo_session_resume(void);
 95
 96int luo_preserve_file(struct luo_file_set *file_set, u64 token, int fd);
 97void luo_file_unpreserve_files(struct luo_file_set *file_set);
 98int luo_file_freeze(struct luo_file_set *file_set,
 99		    struct luo_file_set_ser *file_set_ser);
100void luo_file_unfreeze(struct luo_file_set *file_set,
101		       struct luo_file_set_ser *file_set_ser);
102int luo_retrieve_file(struct luo_file_set *file_set, u64 token,
103		      struct file **filep);
104int luo_file_finish(struct luo_file_set *file_set);
105int luo_file_deserialize(struct luo_file_set *file_set,
106			 struct luo_file_set_ser *file_set_ser);
107void luo_file_set_init(struct luo_file_set *file_set);
108void luo_file_set_destroy(struct luo_file_set *file_set);
109
110#endif /* _LINUX_LUO_INTERNAL_H */