LXR linux/include/linux/decompress/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/* A trivial malloc implementation, adapted from
  29 *  malloc by Hannu Savolainen 1993 and Matthias Urlichs 1994
  30 */
  31STATIC_RW_DATA unsigned long malloc_ptr;
  32STATIC_RW_DATA int malloc_count;
  33
  34static void *malloc(int size)
  35{
  36        void *p;
  37
  38        if (size < 0)
  39                return NULL;
  40        if (!malloc_ptr)
  41                malloc_ptr = free_mem_ptr;
  42
  43        malloc_ptr = (malloc_ptr + 3) & ~3;     /* Align */
  44
  45        p = (void *)malloc_ptr;
  46        malloc_ptr += size;
  47
  48        if (free_mem_end_ptr && malloc_ptr >= free_mem_end_ptr)
  49                return NULL;
  50
  51        malloc_count++;
  52        return p;
  53}
  54
  55static void free(void *where)
  56{
  57        malloc_count--;
  58        if (!malloc_count)
  59                malloc_ptr = free_mem_ptr;
  60}
  61
  62#define large_malloc(a) malloc(a)
  63#define large_free(a) free(a)
  64
  65#define INIT
  66
  67#else /* STATIC */
  68
  69/* Code active when compiled standalone for use when loading ramdisk: */
  70
  71#include <linux/kernel.h>
  72#include <linux/fs.h>
  73#include <linux/string.h>
  74#include <linux/slab.h>
  75#include <linux/vmalloc.h>
  76
  77/* Use defines rather than static inline in order to avoid spurious
  78 * warnings when not needed (indeed large_malloc / large_free are not
  79 * needed by inflate */
  80
  81#define malloc(a) kmalloc(a, GFP_KERNEL)
  82#define free(a) kfree(a)
  83
  84#define large_malloc(a) vmalloc(a)
  85#define large_free(a) vfree(a)
  86
  87#define INIT __init
  88#define STATIC
  89
  90#include <linux/init.h>
  91
  92#endif /* STATIC */
  93
  94#endif /* DECOMPR_MM_H */
  95