1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright 2017, Anshuman Khandual, IBM Corp.
4  *
5  * Works on architectures which support 128TB virtual
6  * address range and beyond.
7  */
8 #include <stdio.h>
9 #include <stdlib.h>
10 #include <string.h>
11 #include <unistd.h>
12 #include <errno.h>
13 #include <sys/mman.h>
14 #include <sys/time.h>
15 
16 /*
17  * Maximum address range mapped with a single mmap()
18  * call is little bit more than 1GB. Hence 1GB is
19  * chosen as the single chunk size for address space
20  * mapping.
21  */
22 
23 #define SZ_1GB	(1024 * 1024 * 1024UL)
24 #define SZ_1TB	(1024 * 1024 * 1024 * 1024UL)
25 
26 #define MAP_CHUNK_SIZE	SZ_1GB
27 
28 /*
29  * Address space till 128TB is mapped without any hint
30  * and is enabled by default. Address space beyond 128TB
31  * till 512TB is obtained by passing hint address as the
32  * first argument into mmap() system call.
33  *
34  * The process heap address space is divided into two
35  * different areas one below 128TB and one above 128TB
36  * till it reaches 512TB. One with size 128TB and the
37  * other being 384TB.
38  *
39  * On Arm64 the address space is 256TB and support for
40  * high mappings up to 4PB virtual address space has
41  * been added.
42  */
43 
44 #define NR_CHUNKS_128TB   ((128 * SZ_1TB) / MAP_CHUNK_SIZE) /* Number of chunks for 128TB */
45 #define NR_CHUNKS_256TB   (NR_CHUNKS_128TB * 2UL)
46 #define NR_CHUNKS_384TB   (NR_CHUNKS_128TB * 3UL)
47 #define NR_CHUNKS_3840TB  (NR_CHUNKS_128TB * 30UL)
48 
49 #define ADDR_MARK_128TB  (1UL << 47) /* First address beyond 128TB */
50 #define ADDR_MARK_256TB  (1UL << 48) /* First address beyond 256TB */
51 
52 #ifdef __aarch64__
53 #define HIGH_ADDR_MARK  ADDR_MARK_256TB
54 #define HIGH_ADDR_SHIFT 49
55 #define NR_CHUNKS_LOW   NR_CHUNKS_256TB
56 #define NR_CHUNKS_HIGH  NR_CHUNKS_3840TB
57 #else
58 #define HIGH_ADDR_MARK  ADDR_MARK_128TB
59 #define HIGH_ADDR_SHIFT 48
60 #define NR_CHUNKS_LOW   NR_CHUNKS_128TB
61 #define NR_CHUNKS_HIGH  NR_CHUNKS_384TB
62 #endif
63 
64 static char *hind_addr(void)
65 {
66 	int bits = HIGH_ADDR_SHIFT + rand() % (63 - HIGH_ADDR_SHIFT);
67 
68 	return (char *) (1UL << bits);
69 }
70 
71 static int validate_addr(char *ptr, int high_addr)
72 {
73 	unsigned long addr = (unsigned long) ptr;
74 
75 	if (high_addr) {
76 		if (addr < HIGH_ADDR_MARK) {
77 			printf("Bad address %lx\n", addr);
78 			return 1;
79 		}
80 		return 0;
81 	}
82 
83 	if (addr > HIGH_ADDR_MARK) {
84 		printf("Bad address %lx\n", addr);
85 		return 1;
86 	}
87 	return 0;
88 }
89 
90 static int validate_lower_address_hint(void)
91 {
92 	char *ptr;
93 
94 	ptr = mmap((void *) (1UL << 45), MAP_CHUNK_SIZE, PROT_READ |
95 			PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
96 
97 	if (ptr == MAP_FAILED)
98 		return 0;
99 
100 	return 1;
101 }
102 
103 int main(int argc, char *argv[])
104 {
105 	char *ptr[NR_CHUNKS_LOW];
106 	char **hptr;
107 	char *hint;
108 	unsigned long i, lchunks, hchunks;
109 
110 	for (i = 0; i < NR_CHUNKS_LOW; i++) {
111 		ptr[i] = mmap(NULL, MAP_CHUNK_SIZE, PROT_READ | PROT_WRITE,
112 					MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
113 
114 		if (ptr[i] == MAP_FAILED) {
115 			if (validate_lower_address_hint())
116 				return 1;
117 			break;
118 		}
119 
120 		if (validate_addr(ptr[i], 0))
121 			return 1;
122 	}
123 	lchunks = i;
124 	hptr = (char **) calloc(NR_CHUNKS_HIGH, sizeof(char *));
125 	if (hptr == NULL)
126 		return 1;
127 
128 	for (i = 0; i < NR_CHUNKS_HIGH; i++) {
129 		hint = hind_addr();
130 		hptr[i] = mmap(hint, MAP_CHUNK_SIZE, PROT_READ | PROT_WRITE,
131 					MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
132 
133 		if (hptr[i] == MAP_FAILED)
134 			break;
135 
136 		if (validate_addr(hptr[i], 1))
137 			return 1;
138 	}
139 	hchunks = i;
140 
141 	for (i = 0; i < lchunks; i++)
142 		munmap(ptr[i], MAP_CHUNK_SIZE);
143 
144 	for (i = 0; i < hchunks; i++)
145 		munmap(hptr[i], MAP_CHUNK_SIZE);
146 
147 	free(hptr);
148 	return 0;
149 }
150