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 #define MAP_NORESERVE 0
26 static int dev_zero
= -1;
30 addrspace_free(void *v
__attribute__ ((unused
)), uintptr n
__attribute__ ((unused
)))
33 size_t page_size
= getpagesize();
38 for(off
= 0; off
< n
; off
+= page_size
)
39 if(mincore((char *)v
+ off
, page_size
, (void *)&one_byte
) != -1
47 mmap_fixed(byte
*v
, uintptr n
, int32 prot
, int32 flags
, int32 fd
, uint32 offset
)
51 p
= runtime_mmap((void *)v
, n
, prot
, flags
, fd
, offset
);
52 if(p
!= v
&& addrspace_free(v
, n
)) {
53 // On some systems, mmap ignores v without
54 // MAP_FIXED, so retry if the address space is free.
57 p
= runtime_mmap((void *)v
, n
, prot
, flags
|MAP_FIXED
, fd
, offset
);
63 runtime_SysAlloc(uintptr n
)
72 dev_zero
= open("/dev/zero", O_RDONLY
);
74 runtime_printf("open /dev/zero: errno=%d\n", errno
);
81 p
= runtime_mmap(nil
, n
, PROT_READ
|PROT_WRITE
, MAP_ANON
|MAP_PRIVATE
, fd
, 0);
82 if (p
== MAP_FAILED
) {
84 runtime_printf("runtime: mmap: access denied\n");
85 runtime_printf("if you're running SELinux, enable execmem for this process.\n");
89 runtime_printf("runtime: mmap: too much locked memory (check 'ulimit -l').\n");
98 runtime_SysUnused(void *v
__attribute__ ((unused
)), uintptr n
__attribute__ ((unused
)))
101 runtime_madvise(v
, n
, MADV_DONTNEED
);
106 runtime_SysFree(void *v
, uintptr n
)
109 runtime_munmap(v
, n
);
113 runtime_SysReserve(void *v
, uintptr n
)
119 if (dev_zero
== -1) {
120 dev_zero
= open("/dev/zero", O_RDONLY
);
122 runtime_printf("open /dev/zero: errno=%d\n", errno
);
129 // On 64-bit, people with ulimit -v set complain if we reserve too
130 // much address space. Instead, assume that the reservation is okay
131 // if we can reserve at least 64K and check the assumption in SysMap.
132 // Only user-mode Linux (UML) rejects these requests.
133 if(sizeof(void*) == 8 && (uintptr
)v
>= 0xffffffffU
) {
134 p
= mmap_fixed(v
, 64<<10, PROT_NONE
, MAP_ANON
|MAP_PRIVATE
, fd
, 0);
137 runtime_munmap(p
, 64<<10);
141 // Use the MAP_NORESERVE mmap() flag here because typically most of
142 // this reservation will never be used. It does not make sense
143 // reserve a huge amount of unneeded swap space. This is important on
144 // systems which do not overcommit memory by default.
145 p
= runtime_mmap(v
, n
, PROT_NONE
, MAP_ANON
|MAP_PRIVATE
|MAP_NORESERVE
, fd
, 0);
152 runtime_SysMap(void *v
, uintptr n
)
160 if (dev_zero
== -1) {
161 dev_zero
= open("/dev/zero", O_RDONLY
);
163 runtime_printf("open /dev/zero: errno=%d\n", errno
);
170 // On 64-bit, we don't actually have v reserved, so tread carefully.
171 if(sizeof(void*) == 8 && (uintptr
)v
>= 0xffffffffU
) {
172 p
= mmap_fixed(v
, n
, PROT_READ
|PROT_WRITE
, MAP_ANON
|MAP_PRIVATE
, fd
, 0);
173 if(p
== MAP_FAILED
&& errno
== ENOMEM
)
174 runtime_throw("runtime: out of memory");
176 runtime_printf("runtime: address space conflict: map(%p) = %p\n", v
, p
);
177 runtime_throw("runtime: address space conflict");
182 p
= runtime_mmap(v
, n
, PROT_READ
|PROT_WRITE
, MAP_ANON
|MAP_FIXED
|MAP_PRIVATE
, fd
, 0);
183 if(p
== MAP_FAILED
&& errno
== ENOMEM
)
184 runtime_throw("runtime: out of memory");
186 runtime_throw("runtime: cannot map pages in arena address space");