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125 lines
3.5 KiB
C
125 lines
3.5 KiB
C
/* mm.h - prototypes and declarations for memory manager */
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/*
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* GRUB -- GRand Unified Bootloader
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* Copyright (C) 2002,2007 Free Software Foundation, Inc.
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*
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* GRUB is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* GRUB is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef _MM_H
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#define _MM_H 1
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#include <stddef.h>
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#include <stdint.h>
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/* Magic words. */
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#define MM_FREE_MAGIC 0x2d3c2808
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#define MM_ALLOC_MAGIC 0x6db08fa4
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/* A header describing a block of memory - either allocated or free */
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typedef struct mm_header
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{
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/*
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* The 'next' free block in this region's circular free list.
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* Only meaningful if the block is free.
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*/
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struct mm_header *next;
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/* The block size, not in bytes but the number of cells of
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* GRUB_MM_ALIGN bytes. Includes the header cell.
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*/
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size_t size;
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/* either free or alloc magic, depending on the block type. */
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size_t magic;
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/* pad to cell size: see the top of kern/mm.c. */
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#if SIZEOF_VOID_P == 4
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char padding[4];
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#elif SIZEOF_VOID_P == 8
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char padding[8];
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#else
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# error "unknown word size"
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#endif
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}
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*mm_header_t;
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#if SIZEOF_VOID_P == 4
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# define MM_ALIGN_LOG2 4
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#elif SIZEOF_VOID_P == 8
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# define MM_ALIGN_LOG2 5
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#endif
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#define MM_ALIGN (1 << MM_ALIGN_LOG2)
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/* A region from which we can make allocations. */
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typedef struct mm_region
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{
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/* The first free block in this region. */
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struct mm_header *first;
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/*
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* The next region in the linked list of regions. Regions are initially
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* sorted in order of increasing size, but can grow, in which case the
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* ordering may not be preserved.
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*/
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struct mm_region *next;
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/*
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* A mm_region will always be aligned to cell size. The pre-size is
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* the number of bytes we were given but had to skip in order to get that
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* alignment.
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*/
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size_t pre_size;
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/*
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* Likewise, the post-size is the number of bytes we wasted at the end
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* of the allocation because it wasn't a multiple of MM_ALIGN
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*/
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size_t post_size;
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/* How many bytes are in this region? (free and allocated) */
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size_t size;
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/* pad to a multiple of cell size */
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char padding[3 * SIZEOF_VOID_P];
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}
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*mm_region_t;
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static inline void
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mm_size_sanity_check (void)
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{
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/* Ensure we preserve alignment when doing h = (mm_header_t) (r + 1). */
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COMPILE_TIME_ASSERT ((sizeof (struct mm_region) %
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sizeof (struct mm_header)) == 0);
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/*
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* MM_ALIGN is supposed to represent cell size, and a mm_header is
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* supposed to be 1 cell.
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*/
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COMPILE_TIME_ASSERT (sizeof (struct mm_header) == MM_ALIGN);
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}
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#define MM_ADD_REGION_NONE 0
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#define MM_ADD_REGION_CONSECUTIVE (1 << 0)
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/*
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* Function used to request memory regions of `size_t` bytes. The second
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* parameter is a bitfield of `MM_ADD_REGION` flags.
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*/
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typedef int (*mm_add_region_func_t) (size_t, unsigned int);
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extern void bios_mm_init_region (void *addr, size_t size);
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extern void *bios_memalign (size_t align, size_t size);
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#endif /* ! _MM_H */
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