1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Copyright 2019 Google LLC
4 */
5
6#ifndef __LINUX_BLK_CRYPTO_PROFILE_H
7#define __LINUX_BLK_CRYPTO_PROFILE_H
8
9#include <linux/bio.h>
10#include <linux/blk-crypto.h>
11
12struct blk_crypto_profile;
13
14/**
15 * struct blk_crypto_ll_ops - functions to control inline encryption hardware
16 *
17 * Low-level operations for controlling inline encryption hardware.  This
18 * interface must be implemented by storage drivers that support inline
19 * encryption.  All functions may sleep, are serialized by profile->lock, and
20 * are never called while profile->dev (if set) is runtime-suspended.
21 */
22struct blk_crypto_ll_ops {
23
24	/**
25	 * @keyslot_program: Program a key into the inline encryption hardware.
26	 *
27	 * Program @key into the specified @slot in the inline encryption
28	 * hardware, overwriting any key that the keyslot may already contain.
29	 * The keyslot is guaranteed to not be in-use by any I/O.
30	 *
31	 * This is required if the device has keyslots.  Otherwise (i.e. if the
32	 * device is a layered device, or if the device is real hardware that
33	 * simply doesn't have the concept of keyslots) it is never called.
34	 *
35	 * Must return 0 on success, or -errno on failure.
36	 */
37	int (*keyslot_program)(struct blk_crypto_profile *profile,
38			       const struct blk_crypto_key *key,
39			       unsigned int slot);
40
41	/**
42	 * @keyslot_evict: Evict a key from the inline encryption hardware.
43	 *
44	 * If the device has keyslots, this function must evict the key from the
45	 * specified @slot.  The slot will contain @key, but there should be no
46	 * need for the @key argument to be used as @slot should be sufficient.
47	 * The keyslot is guaranteed to not be in-use by any I/O.
48	 *
49	 * If the device doesn't have keyslots itself, this function must evict
50	 * @key from any underlying devices.  @slot won't be valid in this case.
51	 *
52	 * If there are no keyslots and no underlying devices, this function
53	 * isn't required.
54	 *
55	 * Must return 0 on success, or -errno on failure.
56	 */
57	int (*keyslot_evict)(struct blk_crypto_profile *profile,
58			     const struct blk_crypto_key *key,
59			     unsigned int slot);
60};
61
62/**
63 * struct blk_crypto_profile - inline encryption profile for a device
64 *
65 * This struct contains a storage device's inline encryption capabilities (e.g.
66 * the supported crypto algorithms), driver-provided functions to control the
67 * inline encryption hardware (e.g. programming and evicting keys), and optional
68 * device-independent keyslot management data.
69 */
70struct blk_crypto_profile {
71
72	/* public: Drivers must initialize the following fields. */
73
74	/**
75	 * @ll_ops: Driver-provided functions to control the inline encryption
76	 * hardware, e.g. program and evict keys.
77	 */
78	struct blk_crypto_ll_ops ll_ops;
79
80	/**
81	 * @max_dun_bytes_supported: The maximum number of bytes supported for
82	 * specifying the data unit number (DUN).  Specifically, the range of
83	 * supported DUNs is 0 through (1 << (8 * max_dun_bytes_supported)) - 1.
84	 */
85	unsigned int max_dun_bytes_supported;
86
87	/**
88	 * @modes_supported: Array of bitmasks that specifies whether each
89	 * combination of crypto mode and data unit size is supported.
90	 * Specifically, the i'th bit of modes_supported[crypto_mode] is set if
91	 * crypto_mode can be used with a data unit size of (1 << i).  Note that
92	 * only data unit sizes that are powers of 2 can be supported.
93	 */
94	unsigned int modes_supported[BLK_ENCRYPTION_MODE_MAX];
95
96	/**
97	 * @dev: An optional device for runtime power management.  If the driver
98	 * provides this device, it will be runtime-resumed before any function
99	 * in @ll_ops is called and will remain resumed during the call.
100	 */
101	struct device *dev;
102
103	/* private: The following fields shouldn't be accessed by drivers. */
104
105	/* Number of keyslots, or 0 if not applicable */
106	unsigned int num_slots;
107
108	/*
109	 * Serializes all calls to functions in @ll_ops as well as all changes
110	 * to @slot_hashtable.  This can also be taken in read mode to look up
111	 * keyslots while ensuring that they can't be changed concurrently.
112	 */
113	struct rw_semaphore lock;
114	struct lock_class_key lockdep_key;
115
116	/* List of idle slots, with least recently used slot at front */
117	wait_queue_head_t idle_slots_wait_queue;
118	struct list_head idle_slots;
119	spinlock_t idle_slots_lock;
120
121	/*
122	 * Hash table which maps struct *blk_crypto_key to keyslots, so that we
123	 * can find a key's keyslot in O(1) time rather than O(num_slots).
124	 * Protected by 'lock'.
125	 */
126	struct hlist_head *slot_hashtable;
127	unsigned int log_slot_ht_size;
128
129	/* Per-keyslot data */
130	struct blk_crypto_keyslot *slots;
131};
132
133int blk_crypto_profile_init(struct blk_crypto_profile *profile,
134			    unsigned int num_slots);
135
136int devm_blk_crypto_profile_init(struct device *dev,
137				 struct blk_crypto_profile *profile,
138				 unsigned int num_slots);
139
140unsigned int blk_crypto_keyslot_index(struct blk_crypto_keyslot *slot);
141
142void blk_crypto_reprogram_all_keys(struct blk_crypto_profile *profile);
143
144void blk_crypto_profile_destroy(struct blk_crypto_profile *profile);
145
146void blk_crypto_intersect_capabilities(struct blk_crypto_profile *parent,
147				       const struct blk_crypto_profile *child);
148
149bool blk_crypto_has_capabilities(const struct blk_crypto_profile *target,
150				 const struct blk_crypto_profile *reference);
151
152void blk_crypto_update_capabilities(struct blk_crypto_profile *dst,
153				    const struct blk_crypto_profile *src);
154
155#endif /* __LINUX_BLK_CRYPTO_PROFILE_H */
156