malloc.h

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#ifndef _IPXE_MALLOC_H
#define _IPXE_MALLOC_H

#include <stdint.h>

/** @file
 *
 * Dynamic memory allocation
 *
 */

FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );

/*
 * Prototypes for the standard functions (malloc() et al) are in
 * stdlib.h.  Include <ipxe/malloc.h> only if you need the
 * non-standard functions, such as malloc_phys().
 *
 */
#include <stdlib.h>
#include <ipxe/list.h>
#include <ipxe/tables.h>
#include <valgrind/memcheck.h>

/**
 * Address for zero-length memory blocks
 *
 * @c malloc(0) or @c realloc(ptr,0) will return the special value @c
 * NOWHERE.  Calling @c free(NOWHERE) will have no effect.
 *
 * This is consistent with the ANSI C standards, which state that
 * "either NULL or a pointer suitable to be passed to free()" must be
 * returned in these cases.  Using a special non-NULL value means that
 * the caller can take a NULL return value to indicate failure,
 * without first having to check for a requested size of zero.
 *
 * Code outside of the memory allocators themselves does not ever need
 * to refer to the actual value of @c NOWHERE; this is an internal
 * definition.
 */
#define NOWHERE ( ( void * ) ~( ( intptr_t ) 0 ) )

/** A heap */
struct heap {
        /** List of free memory blocks */
        struct list_head blocks;

        /** Alignment for free memory blocks */
        size_t align;
        /** Alignment for size-tracked allocations */
        size_t ptr_align;

        /** Total amount of free memory */
        size_t freemem;
        /** Total amount of used memory */
        size_t usedmem;
        /** Maximum amount of used memory */
        size_t maxusedmem;

        /**
         * Attempt to grow heap (optional)
         *
         * @v size              Failed allocation size
         * @ret grown           Heap has grown: retry allocations
         */
        unsigned int ( * grow ) ( size_t size );
        /**
         * Allow heap to shrink (optional)
         *
         * @v ptr               Start of free block
         * @v size              Size of free block
         * @ret shrunk          Heap has shrunk: discard block
         *
         * Note that the discarded block will be accessed once after
         * this method returns, in order to clear the free block
         * metadata.
         */
        unsigned int ( * shrink ) ( void *ptr, size_t size );
};

extern void * heap_realloc ( struct heap *heap, void *old_ptr,
                             size_t new_size );
extern void heap_dump ( struct heap *heap );
extern void heap_populate ( struct heap *heap, void *start, size_t len );

extern void * __malloc malloc_phys_offset ( size_t size, size_t phys_align,
                                            size_t offset );
extern void * __malloc malloc_phys ( size_t size, size_t phys_align );
extern void free_phys ( void *ptr, size_t size );

/** A cache discarder */
struct cache_discarder {
        /**
         * Discard some cached data
         *
         * @ret discarded       Number of cached items discarded
         */
        unsigned int ( * discard ) ( void );
};

/** Cache discarder table */
#define CACHE_DISCARDERS __table ( struct cache_discarder, "cache_discarders" )

/** Declare a cache discarder */
#define __cache_discarder( cost ) __table_entry ( CACHE_DISCARDERS, cost )

/** @defgroup cache_cost Cache discarder costs
 *
 * @{
 */

#define CACHE_CHEAP     01      /**< Items with a low replacement cost */
#define CACHE_NORMAL    02      /**< Items with a normal replacement cost */
#define CACHE_EXPENSIVE 03      /**< Items with a high replacement cost */

/** @} */

#endif /* _IPXE_MALLOC_H */