1 | /* |
2 | * Copyright (c) 2020-2021 Apple Inc. All rights reserved. |
3 | * |
4 | * @APPLE_LICENSE_HEADER_START@ |
5 | * |
6 | * This file contains Original Code and/or Modifications of Original Code |
7 | * as defined in and that are subject to the Apple Public Source License |
8 | * Version 2.0 (the 'License'). You may not use this file except in |
9 | * compliance with the License. Please obtain a copy of the License at |
10 | * http://www.opensource.apple.com/apsl/ and read it before using this |
11 | * file. |
12 | * |
13 | * The Original Code and all software distributed under the License are |
14 | * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER |
15 | * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, |
16 | * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, |
17 | * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. |
18 | * Please see the License for the specific language governing rights and |
19 | * limitations under the License. |
20 | * |
21 | * @APPLE_LICENSE_HEADER_END@ |
22 | */ |
23 | |
24 | #ifndef log_mem_h |
25 | #define log_mem_h |
26 | |
27 | #include <stddef.h> |
28 | #include <stdint.h> |
29 | #include <sys/param.h> |
30 | |
31 | /* |
32 | * A simple allocator on a top of a plain byte array. Primarily intended to |
33 | * support OS kernel logging in order to avoid dependency to VM. |
34 | */ |
35 | typedef struct logmem_s { |
36 | lck_spin_t lm_lock; |
37 | uint8_t *lm_mem; |
38 | uint8_t *lm_mem_map; |
39 | size_t lm_mem_size; |
40 | size_t lm_cap_order; |
41 | size_t lm_min_order; |
42 | size_t lm_max_order; |
43 | uint32_t lm_cnt_allocations; |
44 | uint32_t lm_cnt_failed_size; |
45 | uint32_t lm_cnt_failed_full; |
46 | uint32_t lm_cnt_failed_lmoff; |
47 | uint32_t lm_cnt_free; |
48 | } logmem_t; |
49 | |
50 | /* |
51 | * Initializes dynamically allocated logmem. The caller is responsible for |
52 | * allocating and providing backing memory for both data and the bitmap. |
53 | * LOGMEM_SIZE and LOGMEM_MAP_SIZE provide a way to determine the right sizes. |
54 | */ |
55 | void logmem_init(logmem_t *, void *, size_t, size_t, size_t, size_t); |
56 | |
57 | /* |
58 | * Returns true if the logmem is initialized, false otherwise. |
59 | */ |
60 | bool logmem_ready(const logmem_t *); |
61 | |
62 | /* |
63 | * Allocates memory from a respective logmem. Returns a pointer to the beginning |
64 | * of the allocated block. The resulting size of the allocated block is equal or |
65 | * bigger than the size passed in during the call. The function comes in two |
66 | * flavours, locking and non-locking. The caller is responsible for choosing the |
67 | * right one based on where and how the logmem is used. |
68 | */ |
69 | void *logmem_alloc(logmem_t *, size_t *); |
70 | void *logmem_alloc_locked(logmem_t *, size_t *); |
71 | |
72 | /* |
73 | * Frees memory previously allocated by logmem_alloc*(). The caller must call |
74 | * logmem_free*() with exact pointer and size value returned by logmem_alloc*(). |
75 | * The function comes in two flavours, locking and non-locking. The caller is |
76 | * responsible for choosing the right one based on where and how the logmem is |
77 | * used. |
78 | */ |
79 | void logmem_free(logmem_t *, void *, size_t); |
80 | void logmem_free_locked(logmem_t *, void *, size_t); |
81 | |
82 | /* |
83 | * Returns the maximum memory size allocatable by the logmem. |
84 | */ |
85 | size_t logmem_max_size(const logmem_t *); |
86 | |
87 | /* |
88 | * Returns true if logmem is empty, false otherwise. |
89 | */ |
90 | bool logmem_empty(const logmem_t *); |
91 | |
92 | /* |
93 | * Returns an amount of memory the logmem needs to be initialized with in order |
94 | * to provide allocations and to maintain its internal state. The caller should |
95 | * use this function to get the right amount, allocate the memory accodingly and |
96 | * pass it to logmem_init(). |
97 | */ |
98 | size_t logmem_required_size(size_t, size_t); |
99 | |
100 | #endif /* log_mem_h */ |
101 | |