/*
* Copyright (c) 2020-2021 Apple Inc. All rights reserved.
*
* @APPLE_LICENSE_HEADER_START@
*
* This file contains Original Code and/or Modifications of Original Code
* as defined in and that are subject to the Apple Public Source License
* Version 2.0 (the 'License'). You may not use this file except in
* compliance with the License. Please obtain a copy of the License at
* http://www.opensource.apple.com/apsl/ and read it before using this
* file.
*
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
* Please see the License for the specific language governing rights and
* limitations under the License.
*
* @APPLE_LICENSE_HEADER_END@
*/
#ifndef log_mem_h
#define log_mem_h
#include <stddef.h>
#include <stdint.h>
#include <sys/param.h>
/*
* A simple allocator on a top of a plain byte array. Primarily intended to
* support OS kernel logging in order to avoid dependency to VM.
*/
typedef struct logmem_s {
lck_spin_t lm_lock;
uint8_t *lm_mem;
uint8_t *lm_mem_map;
size_t lm_mem_size;
size_t lm_cap_order;
size_t lm_min_order;
size_t lm_max_order;
uint32_t lm_cnt_allocations;
uint32_t lm_cnt_failed_size;
uint32_t lm_cnt_failed_full;
uint32_t lm_cnt_failed_lmoff;
uint32_t lm_cnt_free;
} logmem_t;
/*
* Initializes dynamically allocated logmem. The caller is responsible for
* allocating and providing backing memory for both data and the bitmap.
* LOGMEM_SIZE and LOGMEM_MAP_SIZE provide a way to determine the right sizes.
*/
void logmem_init(logmem_t *, void *, size_t, size_t, size_t, size_t);
/*
* Returns true if the logmem is initialized, false otherwise.
*/
bool logmem_ready(const logmem_t *);
/*
* Allocates memory from a respective logmem. Returns a pointer to the beginning
* of the allocated block. The resulting size of the allocated block is equal or
* bigger than the size passed in during the call. The function comes in two
* flavours, locking and non-locking. The caller is responsible for choosing the
* right one based on where and how the logmem is used.
*/
void *logmem_alloc(logmem_t *, size_t *);
void *logmem_alloc_locked(logmem_t *, size_t *);
/*
* Frees memory previously allocated by logmem_alloc*(). The caller must call
* logmem_free*() with exact pointer and size value returned by logmem_alloc*().
* The function comes in two flavours, locking and non-locking. The caller is
* responsible for choosing the right one based on where and how the logmem is
* used.
*/
void logmem_free(logmem_t *, void *, size_t);
void logmem_free_locked(logmem_t *, void *, size_t);
/*
* Returns the maximum memory size allocatable by the logmem.
*/
size_t logmem_max_size(const logmem_t *);
/*
* Returns true if logmem is empty, false otherwise.
*/
bool logmem_empty(const logmem_t *);
/*
* Returns an amount of memory the logmem needs to be initialized with in order
* to provide allocations and to maintain its internal state. The caller should
* use this function to get the right amount, allocate the memory accodingly and
* pass it to logmem_init().
*/
size_t logmem_required_size(size_t, size_t);
#endif /* log_mem_h */