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}