xref: /aosp_15_r20/external/coreboot/src/lib/malloc.c (revision b9411a12aaaa7e1e6a6fb7c5e057f44ee179a49c)
1 /* SPDX-License-Identifier: GPL-2.0-only */
2 
3 #include <console/console.h>
4 #include <stdlib.h>
5 #include <string.h>
6 
7 #if CONFIG(DEBUG_MALLOC)
8 #define MALLOCDBG(x...) printk(BIOS_SPEW, x)
9 #else
10 #define MALLOCDBG(x...)
11 #endif
12 
13 extern unsigned char _heap, _eheap;
14 static void *free_mem_ptr = &_heap;		/* Start of heap */
15 static void *free_mem_end_ptr = &_eheap;	/* End of heap */
16 static void *free_last_alloc_ptr = &_heap;	/* End of heap before
17 						   last allocation */
18 
19 /* We don't restrict the boundary. This is firmware,
20  * you are supposed to know what you are doing.
21  */
memalign(size_t boundary,size_t size)22 void *memalign(size_t boundary, size_t size)
23 {
24 	void *p;
25 
26 	MALLOCDBG("%s Enter, boundary %zu, size %zu, free_mem_ptr %p\n",
27 		__func__, boundary, size, free_mem_ptr);
28 
29 	free_mem_ptr = (void *)ALIGN_UP((unsigned long)free_mem_ptr, boundary);
30 
31 	p = free_mem_ptr;
32 	free_mem_ptr += size;
33 	/*
34 	 * Store last allocation pointer after ALIGN, as malloc() will
35 	 * return it. This may cause n bytes of gap between allocations
36 	 * where n < boundary.
37 	 */
38 	free_last_alloc_ptr = p;
39 
40 	if (free_mem_ptr >= free_mem_end_ptr) {
41 		printk(BIOS_ERR, "%s(boundary=%zu, size=%zu): failed: ",
42 				__func__, boundary, size);
43 		printk(BIOS_ERR, "Tried to round up free_mem_ptr %p to %p\n",
44 				p, free_mem_ptr);
45 		printk(BIOS_ERR, "but free_mem_end_ptr is %p\n",
46 				free_mem_end_ptr);
47 		printk(BIOS_ERR, "Error! %s: Out of memory "
48 				"(free_mem_ptr >= free_mem_end_ptr)",
49 				__func__);
50 		return NULL;
51 	}
52 
53 	MALLOCDBG("%s %p\n", __func__, p);
54 
55 	return p;
56 }
57 
malloc(size_t size)58 void *malloc(size_t size)
59 {
60 	return memalign(sizeof(u64), size);
61 }
62 
calloc(size_t nitems,size_t size)63 void *calloc(size_t nitems, size_t size)
64 {
65 	void *p = malloc(nitems * size);
66 	if (p)
67 		memset(p, 0, nitems * size);
68 
69 	return p;
70 }
71 
free(void * ptr)72 void free(void *ptr)
73 {
74 	if (ptr == NULL)
75 		return;
76 
77 	if (ptr < (void *)&_heap || ptr >= free_mem_end_ptr) {
78 		printk(BIOS_WARNING, "Pointer passed to %s is not "
79 					"pointing to the heap\n", __func__);
80 		return;
81 	}
82 
83 	/*
84 	 * Rewind the heap pointer to the end of heap
85 	 * before the last successful malloc().
86 	 */
87 	if (ptr == free_last_alloc_ptr) {
88 		free_mem_ptr = free_last_alloc_ptr;
89 		free_last_alloc_ptr = NULL;
90 	}
91 }
92