path: root/cpukit/include/rtems/rtl/rtl-allocator.h

/* SPDX-License-Identifier: BSD-2-Clause */

/*
 *  COPYRIGHT (c) 2012, 2018, 2023 Chris Johns <chrisj@rtems.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */
/**
 * @file
 *
 * @ingroup rtems_rtl
 *
 * @brief RTEMS Run-Time Linker Allocator
 */

#if !defined (_RTEMS_RTL_ALLOCATOR_H_)
#define _RTEMS_RTL_ALLOCATOR_H_

#include <stdbool.h>

#include "rtl-indirect-ptr.h"

#ifdef __cplusplus
extern "C" {
#endif /* __cplusplus */

/**
 * Define the types of allocation the loader requires.
 *
 * @note It is best to use the object tag for general memory allocation and to
 *       leave the tags with specific access properties to the module data
 */
enum rtems_rtl_alloc_tags {
  RTEMS_RTL_ALLOC_OBJECT,     /**< A generic memory object. */
  RTEMS_RTL_ALLOC_SYMBOL,     /**< Memory used for symbols. */
  RTEMS_RTL_ALLOC_EXTERNAL,   /**< Memory used for external symbols. */
  RTEMS_RTL_ALLOC_READ,       /**< The memory is read only. */
  RTEMS_RTL_ALLOC_READ_WRITE, /**< The memory is read and write. */
  RTEMS_RTL_ALLOC_READ_EXEC   /**< The memory is read and executable. */
};

/**
 * The allocator tag type.
 */
typedef enum rtems_rtl_alloc_tags rtems_rtl_alloc_tag;

/**
 * Define the allocation command the loader requires.
 */
enum rtems_rtl_alloc_cmd {
  RTEMS_RTL_ALLOC_NEW,        /**< Allocate new memory. */
  RTEMS_RTL_ALLOC_DEL,        /**< Delete allocated memory. */
  RTEMS_RTL_ALLOC_RESIZE,     /**< Resize allocated memory. */
  RTEMS_RTL_ALLOC_LOCK,       /**< Lock the allocator. */
  RTEMS_RTL_ALLOC_UNLOCK,     /**< Unlock the allocator. */
  RTEMS_RTL_ALLOC_WR_ENABLE,  /**< Enable writes to the memory. */
  RTEMS_RTL_ALLOC_WR_DISABLE, /**< Disable writes to the memory. */
};

/**
 * The allocator command type.
 */
typedef enum rtems_rtl_alloc_cmd rtems_rtl_alloc_cmd;

/**
 * The number of tags.
 */
#define RTEMS_RTL_ALLOC_TAGS ((size_t) (RTEMS_RTL_ALLOC_READ_EXEC + 1))

/**
 * Allocator handler handles all RTL allocations. It can be hooked and
 * overridded for customised allocation schemes or memory maps.
 *
 * @param allocation The request command.
 * @param tag The type of allocation request.
 * @param address Pointer to the memory address. If an allocation the value is
 *                unspecific on entry and the allocated address or NULL on
 *                exit. The NULL value means the allocation failed. If a delete
 *                or free request the memory address is the block to free. A
 *                free request of NULL is silently ignored.
 * @param size The size of the allocation if an allocation request and
 *             not used if deleting or freeing a previous allocation.
 */
typedef void (*rtems_rtl_allocator)(rtems_rtl_alloc_cmd cmd,
                                    rtems_rtl_alloc_tag tag,
                                    void**              address,
                                    size_t              size);

/**
 * The allocator data.
 */
struct rtems_rtl_alloc_data {
  /**< The memory allocator handler. */
  rtems_rtl_allocator allocator;
  /**< The indirect pointer chains. */
  rtems_chain_control indirects[RTEMS_RTL_ALLOC_TAGS];
};

typedef struct rtems_rtl_alloc_data rtems_rtl_alloc_data;

/**
 * Initialise the allocate data.
 *
 * @param data The data to initialise.
 */
void rtems_rtl_alloc_initialise (rtems_rtl_alloc_data* data);

/**
 * The Runtime Loader allocator new allocates new memory and optionally clear
 * the memory if requested.
 *
 * @param tag The type of allocation request.
 * @param size The size of the allocation.
 * @param zero If true the memory is cleared.
 * @return void* The memory address or NULL is not memory available.
 */
void* rtems_rtl_alloc_new (rtems_rtl_alloc_tag tag, size_t size, bool zero);

/**
 * The Runtime Loader allocator delete deletes allocated memory.
 *
 * @param tag The type of allocation request.
 * @param address The memory address to delete. A NULL is ignored.
 */
void rtems_rtl_alloc_del (rtems_rtl_alloc_tag tag, void* address);

/**
 * The Runtime Loader allocator resize resizes allocated memory.
 *
 * This call resizes a previously allocated block of memory. If the
 * provided address cannot be resized it is deleted and a new block is
 * allocated and the contents of the existing memory is copied.
 *
 *
 * @param tag The type of allocation request.
 * @param address The memory address to resize. A NULL is ignored.
 * @param size The size of the allocation.
 * @param zero If true the memory is cleared.
 * @return void* The memory address or NULL is not memory available.
 */
void* rtems_rtl_alloc_resize (rtems_rtl_alloc_tag tag,
                              void*               address,
                              size_t              size,
                              bool                zero);

/**
 * The Runtime Loader allocator lock. An allocator that depends on a
 * separate allocation process, for example the heap, may need to be
 * locked during loading of an object file to make sure the locality
 * of the memory. This call be used to lock such an allocator.
 *  Allocator calls in this interface are protected by the RTL lock.
 */
void rtems_rtl_alloc_lock (void);

/**
 * The Runtime Loader allocator unlock. An allocator that depends on a
 * separate allocation process, for example the heap, may need to be
 * locked during loading of an object file to make sure the locality
 * of the memory. This call can be used to unlock such an allocator.
 * Allocator calls in this interface are protected by the RTL lock.
 */
void rtems_rtl_alloc_unlock (void);

/**
 * The Runtime Loader allocator enable write on a bloc of allocated memory.
 *
 * @param tag The type of allocation request. Must match the address.
 * @param address The memory address to write enable. A NULL is ignored.
 */
void rtems_rtl_alloc_wr_enable (rtems_rtl_alloc_tag tag, void* address);

/**
 * The Runtime Loader allocator disable write on a bloc of allocated memory.
 *
 * @param tag The type of allocation request. Must match the address.
 * @param address The memory address to write disable. A NULL is ignored.
 */
void rtems_rtl_alloc_wr_disable (rtems_rtl_alloc_tag tag, void* address);

/**
 * Hook the Runtime Loader allocatior. A handler can call the previous handler
 * in the chain to use it for specific tags. The default handler uses the
 * system heap. Do not unhook your handler if memory it allocates has not been
 * returned.
 *
 * @param handler The handler to use as the allocator.
 * @return rtems_rtl_alloc_handler The previous handler.
 */
rtems_rtl_allocator rtems_rtl_alloc_hook (rtems_rtl_allocator handler);

/**
 * Allocate memory to an indirect handle.
 *
 * @param tag The type of allocation request.
 * @param handle The handle to allocate the memory to.
 * @param size The size of the allocation.
 */
void rtems_rtl_alloc_indirect_new (rtems_rtl_alloc_tag tag,
                                   rtems_rtl_ptr*      handle,
                                   size_t              size);

/**
 * Free memory from an indirect handle.
 *
 * @param tag The type of allocation request.
 * @param handle The handle to free the memory from.
 */
void rtems_rtl_alloc_indirect_del (rtems_rtl_alloc_tag tag,
                                   rtems_rtl_ptr*      handle);

/**
 * Return the default tag for text sections.
 *
 * @return The text tag.
 */
rtems_rtl_alloc_tag rtems_rtl_alloc_text_tag (void);

/**
 * Return the default tag for const sections.
 *
 * @return The const tag.
 */
rtems_rtl_alloc_tag rtems_rtl_alloc_const_tag (void);

/**
 * Return the default tag for exception sections.
 *
 * @return The eh tag.
 */
rtems_rtl_alloc_tag rtems_rtl_alloc_eh_tag (void);

/**
 * Return the default tag for data sections.
 *
 * @return The data tag.
 */
rtems_rtl_alloc_tag rtems_rtl_alloc_data_tag (void);

/**
 * Return the default tag for bss sections.
 *
 * @return The bss tag.
 */
rtems_rtl_alloc_tag rtems_rtl_alloc_bss_tag (void);

/**
 * Allocate the memory for a module given the size of the text, const, data and
 * bss sections. If any part of the allocation fails the no memory is
 * allocated.
 *
 * @param text_base Pointer to the text base pointer.
 * @param text_size The size of the read/exec section.
 * @param const_base Pointer to the const base pointer.
 * @param const_size The size of the read only section.
 * @param eh_base Pointer to the eh base pointer.
 * @param eh_size The size of the eh section.
 * @param data_base Pointer to the data base pointer.
 * @param data_size The size of the read/write secton.
 * @param bss_base Pointer to the bss base pointer.
 * @param bss_size The size of the read/write.
 * @retval true The memory has been allocated.
 * @retval false The allocation of memory has failed.
 */
bool rtems_rtl_alloc_module_new (void** text_base, size_t text_size,
                                 void** const_base, size_t const_size,
                                 void** eh_base, size_t eh_size,
                                 void** data_base, size_t data_size,
                                 void** bss_base, size_t bss_size);

/**
 * Resize the allocated memory for a module given the new size of the text,
 * const, data and bss sections. If any part of the allocation fails the
 * allocated is deleted.
 *
 * @param text_base Pointer to the text base pointer.
 * @param text_size The size of the read/exec section.
 * @param const_base Pointer to the const base pointer.
 * @param const_size The size of the read only section.
 * @param eh_base Pointer to the eh base pointer.
 * @param eh_size The size of the eh section.
 * @param data_base Pointer to the data base pointer.
 * @param data_size The size of the read/write secton.
 * @param bss_base Pointer to the bss base pointer.
 * @param bss_size The size of the read/write.
 * @retval true The memory has been allocated.
 * @retval false The allocation of memory has failed.
 */
bool rtems_rtl_alloc_module_resize (void** text_base, size_t text_size,
                                    void** const_base, size_t const_size,
                                    void** eh_base, size_t eh_size,
                                    void** data_base, size_t data_size,
                                    void** bss_base, size_t bss_size);

/**
 * Free the memory allocated to a module.
 *
 * @param text_base Pointer to the text base pointer.
 * @param const_base Pointer to the const base pointer.
 * @param eh_base Pointer to the eh base pointer.
 * @param data_base Pointer to the data base pointer.
 * @param bss_base Pointer to the bss base pointer.
 */
void rtems_rtl_alloc_module_del (void** text_base, void** const_base,
                                 void** eh_base, void** data_base,
                                 void** bss_base);

#ifdef __cplusplus
}
#endif /* __cplusplus */

#endif