1 /* Defining _XOPEN_SOURCE hides the declaration of madvise() on Solaris <
2 11 and the MADV_DONTNEED definition on IRIX 6.5. */
14 #define MAP_ANON MAP_ANONYMOUS
22 static int dev_zero = -1;
26 addrspace_free(void *v __attribute__ ((unused)), uintptr n __attribute__ ((unused)))
29 size_t page_size = getpagesize();
34 for(off = 0; off < n; off += page_size)
35 if(mincore((char *)v + off, page_size, (void *)&one_byte) != -1
43 mmap_fixed(byte *v, uintptr n, int32 prot, int32 flags, int32 fd, uint32 offset)
47 p = runtime_mmap((void *)v, n, prot, flags, fd, offset);
48 if(p != v && addrspace_free(v, n)) {
49 // On some systems, mmap ignores v without
50 // MAP_FIXED, so retry if the address space is free.
53 p = runtime_mmap((void *)v, n, prot, flags|MAP_FIXED, fd, offset);
59 runtime_SysAlloc(uintptr n)
68 dev_zero = open("/dev/zero", O_RDONLY);
70 runtime_printf("open /dev/zero: errno=%d\n", errno);
77 p = runtime_mmap(nil, n, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_ANON|MAP_PRIVATE, fd, 0);
78 if (p == MAP_FAILED) {
80 runtime_printf("runtime: mmap: access denied\n");
81 runtime_printf("if you're running SELinux, enable execmem for this process.\n");
90 runtime_SysUnused(void *v __attribute__ ((unused)), uintptr n __attribute__ ((unused)))
93 runtime_madvise(v, n, MADV_DONTNEED);
98 runtime_SysFree(void *v, uintptr n)
101 runtime_munmap(v, n);
105 runtime_SysReserve(void *v, uintptr n)
111 if (dev_zero == -1) {
112 dev_zero = open("/dev/zero", O_RDONLY);
114 runtime_printf("open /dev/zero: errno=%d\n", errno);
121 // On 64-bit, people with ulimit -v set complain if we reserve too
122 // much address space. Instead, assume that the reservation is okay
123 // if we can reserve at least 64K and check the assumption in SysMap.
124 // Only user-mode Linux (UML) rejects these requests.
125 if(sizeof(void*) == 8 && (uintptr)v >= 0xffffffffU) {
126 p = mmap_fixed(v, 64<<10, PROT_NONE, MAP_ANON|MAP_PRIVATE, fd, 0);
129 runtime_munmap(p, 64<<10);
133 p = runtime_mmap(v, n, PROT_NONE, MAP_ANON|MAP_PRIVATE, fd, 0);
140 runtime_SysMap(void *v, uintptr n)
148 if (dev_zero == -1) {
149 dev_zero = open("/dev/zero", O_RDONLY);
151 runtime_printf("open /dev/zero: errno=%d\n", errno);
158 // On 64-bit, we don't actually have v reserved, so tread carefully.
159 if(sizeof(void*) == 8 && (uintptr)v >= 0xffffffffU) {
160 p = mmap_fixed(v, n, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_ANON|MAP_PRIVATE, fd, 0);
161 if(p == MAP_FAILED && errno == ENOMEM)
162 runtime_throw("runtime: out of memory");
164 runtime_printf("runtime: address space conflict: map(%p) = %p\n", v, p);
165 runtime_throw("runtime: address space conflict");
170 p = runtime_mmap(v, n, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_ANON|MAP_FIXED|MAP_PRIVATE, fd, 0);
172 runtime_throw("runtime: cannot map pages in arena address space");