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  */
  31 STATIC_RW_DATA unsigned long malloc_ptr;
  32 STATIC_RW_DATA int malloc_count;
  33
  34 static 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
  55 static 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 */