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// Copyright 2010 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
#include "runtime.h"
#include "arch_GOARCH.h"
#include "defs_GOOS_GOARCH.h"
#include "os_GOOS.h"
#include "malloc.h"
enum
{
_PAGE_SIZE = 4096,
};
static int32
addrspace_free(void *v, uintptr n)
{
int32 errval;
uintptr chunk;
uintptr off;
static byte vec[4096];
for(off = 0; off < n; off += chunk) {
chunk = _PAGE_SIZE * sizeof vec;
if(chunk > (n - off))
chunk = n - off;
errval = runtime·mincore((int8*)v + off, chunk, vec);
// errval is 0 if success, or -(error_code) if error.
if (errval == 0 || errval != -ENOMEM)
return 0;
}
return 1;
}
static void *
mmap_fixed(byte *v, uintptr n, int32 prot, int32 flags, int32 fd, uint32 offset)
{
void *p;
p = runtime·mmap(v, n, prot, flags, fd, offset);
if(p != v && addrspace_free(v, n)) {
// On some systems, mmap ignores v without
// MAP_FIXED, so retry if the address space is free.
if(p > (void*)4096)
runtime·munmap(p, n);
p = runtime·mmap(v, n, prot, flags|MAP_FIXED, fd, offset);
}
return p;
}
void*
runtime·SysAlloc(uintptr n)
{
void *p;
mstats.sys += n;
p = runtime·mmap(nil, n, PROT_READ|PROT_WRITE, MAP_ANON|MAP_PRIVATE, -1, 0);
if(p < (void*)4096) {
if(p == (void*)EACCES) {
runtime·printf("runtime: mmap: access denied\n");
runtime·printf("if you're running SELinux, enable execmem for this process.\n");
runtime·exit(2);
}
if(p == (void*)EAGAIN) {
runtime·printf("runtime: mmap: too much locked memory (check 'ulimit -l').\n");
runtime·exit(2);
}
return nil;
}
return p;
}
void
runtime·SysUnused(void *v, uintptr n)
{
runtime·madvise(v, n, MADV_DONTNEED);
}
void
runtime·SysFree(void *v, uintptr n)
{
mstats.sys -= n;
runtime·munmap(v, n);
}
void*
runtime·SysReserve(void *v, uintptr n)
{
void *p;
// On 64-bit, people with ulimit -v set complain if we reserve too
// much address space. Instead, assume that the reservation is okay
// if we can reserve at least 64K and check the assumption in SysMap.
// Only user-mode Linux (UML) rejects these requests.
if(sizeof(void*) == 8 && (uintptr)v >= 0xffffffffU) {
p = mmap_fixed(v, 64<<10, PROT_NONE, MAP_ANON|MAP_PRIVATE, -1, 0);
if (p != v)
return nil;
runtime·munmap(p, 64<<10);
return v;
}
p = runtime·mmap(v, n, PROT_NONE, MAP_ANON|MAP_PRIVATE, -1, 0);
if((uintptr)p < 4096 || -(uintptr)p < 4096)
return nil;
return p;
}
void
runtime·SysMap(void *v, uintptr n)
{
void *p;
mstats.sys += n;
// On 64-bit, we don't actually have v reserved, so tread carefully.
if(sizeof(void*) == 8 && (uintptr)v >= 0xffffffffU) {
p = mmap_fixed(v, n, PROT_READ|PROT_WRITE, MAP_ANON|MAP_PRIVATE, -1, 0);
if(p == (void*)ENOMEM)
runtime·throw("runtime: out of memory");
if(p != v) {
runtime·printf("runtime: address space conflict: map(%p) = %p\n", v, p);
runtime·throw("runtime: address space conflict");
}
return;
}
p = runtime·mmap(v, n, PROT_READ|PROT_WRITE, MAP_ANON|MAP_FIXED|MAP_PRIVATE, -1, 0);
if(p == (void*)ENOMEM)
runtime·throw("runtime: out of memory");
if(p != v)
runtime·throw("runtime: cannot map pages in arena address space");
}
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