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1 /*

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 */

24 #ifndef log_mem_h

25 #define log_mem_h

27 #include <stddef.h>

28 #include <stdint.h>

30 /*

31 * A simple allocator on a top of a plain byte array. Primarily intended to

32 * support OS kernel logging in order to avoid dependency to VM.

33 */

34 typedef struct logmem_s {

35 lck_spin_t *lm_lock;

36 uint8_t *lm_mem;

37 uint8_t *lm_mem_map;

38 size_t lm_cap_order;

39 size_t lm_min_order;

40 size_t lm_max_order;

41 uint32_t lm_cnt_allocations;

42 uint32_t lm_cnt_failed_size;

43 uint32_t lm_cnt_failed_full;

44 uint32_t lm_cnt_free;

45 } logmem_t;

47 /*

48 * Static initializer for global instances of logmem. Size order defines the

49 * total amount of logmem memory, the min and max order set the minimum and the

50 * maximum size respectively of the memory allocatable by the given logmem.

51 * Local or dynamically allocated instances of logmem should not be initialized

52 * by this macro.

53 */

54 #define LOGMEM_STATIC_INIT(name, size_order, min_order, max_order) \

55 SIMPLE_LOCK_DECLARE(name##_lck, 0); \

56 logmem_t name = { \

57 .lm_lock = (lck_spin_t *)&name##_lck, \

58 .lm_mem = (uint8_t[(1 << (size_order))]){ 0 }, \

59 .lm_mem_map = (uint8_t[MAX(1, (1 << ((size_order) - (min_order) + 1)) / 8)]){ 0 }, \

60 .lm_cap_order = (size_order), \

61 .lm_max_order = (max_order), \

62 .lm_min_order = (min_order), \

63 .lm_cnt_free = (1 << (size_order)) \

64 };

66 /*

67 * Allocates memory from a respective logmem. Returns a pointer to the beginning

68 * of the allocated block. The resulting size of the allocated block is equal or

69 * bigger than the size passed in during the call.

70 */

 void *logmem_alloc(logmem_t *, size_t *);

73 /*

74 * Frees memory previously allocated by logmem_alloc(). The caller must call

75 * logmem_free() with exact pointer and size value returned by logmem_alloc().

76 */

 void logmem_free(logmem_t *, void *, size_t);

79 /*

80 * Returns the maximum memory size allocatable by the logmem.

81 */

 size_t logmem_max_size(const logmem_t *);

84 #endif /* log_mem_h */