1/*
2 * Copyright 2017, Anshuman Khandual, IBM Corp.
3 * Licensed under GPLv2.
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
58static char *hind_addr(void)
59{
60	int bits = HIGH_ADDR_SHIFT + rand() % (63 - HIGH_ADDR_SHIFT);
61
62	return (char *) (1UL << bits);
63}
64
65static 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
84static 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
97int 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