mm.h

  1/* SPDX-License-Identifier: GPL-2.0 */
  2/*
  3 * linux/compr_mm.h
  4 *
  5 * Memory management for pre-boot and ramdisk uncompressors
  6 *
  7 * Authors: Alain Knaff <alain@knaff.lu>
  8 *
  9 */
 10
 11#ifndef DECOMPR_MM_H
 12#define DECOMPR_MM_H
 13
 14#ifdef STATIC
 15
 16/* Code active when included from pre-boot environment: */
 17
 18/*
 19 * Some architectures want to ensure there is no local data in their
 20 * pre-boot environment, so that data can arbitrarily relocated (via
 21 * GOT references).  This is achieved by defining STATIC_RW_DATA to
 22 * be null.
 23 */
 24#ifndef STATIC_RW_DATA
 25#define STATIC_RW_DATA static
 26#endif
 27
 28/*
 29 * When an architecture needs to share the malloc()/free() implementation
 30 * between compilation units, it needs to have non-local visibility.
 31 */
 32#ifndef MALLOC_VISIBLE
 33#define MALLOC_VISIBLE static
 34#endif
 35
 36/* A trivial malloc implementation, adapted from
 37 *  malloc by Hannu Savolainen 1993 and Matthias Urlichs 1994
 38 */
 39STATIC_RW_DATA unsigned long malloc_ptr;
 40STATIC_RW_DATA int malloc_count;
 41
 42MALLOC_VISIBLE void *malloc(int size)
 43{
 44	void *p;
 45
 46	if (size < 0)
 47		return NULL;
 48	if (!malloc_ptr)
 49		malloc_ptr = free_mem_ptr;
 50
 51	malloc_ptr = (malloc_ptr + 7) & ~7;     /* Align */
 52
 53	p = (void *)malloc_ptr;
 54	malloc_ptr += size;
 55
 56	if (free_mem_end_ptr && malloc_ptr >= free_mem_end_ptr)
 57		return NULL;
 58
 59	malloc_count++;
 60	return p;
 61}
 62
 63MALLOC_VISIBLE void free(void *where)
 64{
 65	malloc_count--;
 66	if (!malloc_count)
 67		malloc_ptr = free_mem_ptr;
 68}
 69
 70#define large_malloc(a) malloc(a)
 71#define large_free(a) free(a)
 72
 73#define INIT
 74
 75#else /* STATIC */
 76
 77/* Code active when compiled standalone for use when loading ramdisk: */
 78
 79#include <linux/kernel.h>
 80#include <linux/fs.h>
 81#include <linux/string.h>
 82#include <linux/slab.h>
 83#include <linux/vmalloc.h>
 84
 85/* Use defines rather than static inline in order to avoid spurious
 86 * warnings when not needed (indeed large_malloc / large_free are not
 87 * needed by inflate */
 88
 89#define malloc(a) kmalloc(a, GFP_KERNEL)
 90#define free(a) kfree(a)
 91
 92#define large_malloc(a) vmalloc(a)
 93#define large_free(a) vfree(a)
 94
 95#define INIT __init
 96#define STATIC
 97
 98#include <linux/init.h>
 99
100#endif /* STATIC */
101
102#endif /* DECOMPR_MM_H */