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 16GB. Hence 16GB is
19  * chosen as the single chunk size for address space
20  * mapping.
21  */
22 #define MAP_CHUNK_SIZE   17179869184UL /* 16GB */
23 
24 /*
25  * Address space till 128TB is mapped without any hint
26  * and is enabled by default. Address space beyond 128TB
27  * till 512TB is obtained by passing hint address as the
28  * first argument into mmap() system call.
29  *
30  * The process heap address space is divided into two
31  * different areas one below 128TB and one above 128TB
32  * till it reaches 512TB. One with size 128TB and the
33  * other being 384TB.
34  *
35  * On Arm64 the address space is 256TB and no high mappings
36  * are supported so far.
37  */
38 
39 #define NR_CHUNKS_128TB   8192UL /* Number of 16GB chunks for 128TB */
40 #define NR_CHUNKS_256TB   (NR_CHUNKS_128TB * 2UL)
41 #define NR_CHUNKS_384TB   (NR_CHUNKS_128TB * 3UL)
42 
43 #define ADDR_MARK_128TB  (1UL << 47) /* First address beyond 128TB */
44 #define ADDR_MARK_256TB  (1UL << 48) /* First address beyond 256TB */
45 
46 #ifdef __aarch64__
47 #define HIGH_ADDR_MARK  ADDR_MARK_256TB
48 #define HIGH_ADDR_SHIFT 49
49 #define NR_CHUNKS_LOW   NR_CHUNKS_256TB
50 #define NR_CHUNKS_HIGH  0
51 #else
52 #define HIGH_ADDR_MARK  ADDR_MARK_128TB
53 #define HIGH_ADDR_SHIFT 48
54 #define NR_CHUNKS_LOW   NR_CHUNKS_128TB
55 #define NR_CHUNKS_HIGH  NR_CHUNKS_384TB
56 #endif
57 
58 static char *hind_addr(void)
59 {
60 	int bits = HIGH_ADDR_SHIFT + rand() % (63 - HIGH_ADDR_SHIFT);
61 
62 	return (char *) (1UL << bits);
63 }
64 
65 static int validate_addr(char *ptr, int high_addr)
66 {
67 	unsigned long addr = (unsigned long) ptr;
68 
69 	if (high_addr) {
70 		if (addr < HIGH_ADDR_MARK) {
71 			printf("Bad address %lx\n", addr);
72 			return 1;
73 		}
74 		return 0;
75 	}
76 
77 	if (addr > HIGH_ADDR_MARK) {
78 		printf("Bad address %lx\n", addr);
79 		return 1;
80 	}
81 	return 0;
82 }
83 
84 static int validate_lower_address_hint(void)
85 {
86 	char *ptr;
87 
88 	ptr = mmap((void *) (1UL << 45), MAP_CHUNK_SIZE, PROT_READ |
89 			PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
90 
91 	if (ptr == MAP_FAILED)
92 		return 0;
93 
94 	return 1;
95 }
96 
97 int main(int argc, char *argv[])
98 {
99 	char *ptr[NR_CHUNKS_LOW];
100 	char *hptr[NR_CHUNKS_HIGH];
101 	char *hint;
102 	unsigned long i, lchunks, hchunks;
103 
104 	for (i = 0; i < NR_CHUNKS_LOW; i++) {
105 		ptr[i] = mmap(NULL, MAP_CHUNK_SIZE, PROT_READ | PROT_WRITE,
106 					MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
107 
108 		if (ptr[i] == MAP_FAILED) {
109 			if (validate_lower_address_hint())
110 				return 1;
111 			break;
112 		}
113 
114 		if (validate_addr(ptr[i], 0))
115 			return 1;
116 	}
117 	lchunks = i;
118 
119 	for (i = 0; i < NR_CHUNKS_HIGH; i++) {
120 		hint = hind_addr();
121 		hptr[i] = mmap(hint, MAP_CHUNK_SIZE, PROT_READ | PROT_WRITE,
122 					MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
123 
124 		if (hptr[i] == MAP_FAILED)
125 			break;
126 
127 		if (validate_addr(hptr[i], 1))
128 			return 1;
129 	}
130 	hchunks = i;
131 
132 	for (i = 0; i < lchunks; i++)
133 		munmap(ptr[i], MAP_CHUNK_SIZE);
134 
135 	for (i = 0; i < hchunks; i++)
136 		munmap(hptr[i], MAP_CHUNK_SIZE);
137 
138 	return 0;
139 }
140