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  */
39 STATIC_RW_DATA unsigned long malloc_ptr;
40 STATIC_RW_DATA int malloc_count;
41 
malloc(int size)42 MALLOC_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 + 3) & ~3;     /* 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 
free(void * where)63 MALLOC_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 */
103