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#include "runtime.h"
#include "defs.h"
#include "os.h"
#include "malloc.h"
enum
{
ENOMEM = 12,
};
static int32
addrspace_free(void *v, uintptr n)
{
uintptr page_size = 4096;
uintptr off;
int8 one_byte;
for(off = 0; off < n; off += page_size) {
int32 errval = runtime·mincore((int8 *)v + off, page_size, (void *)&one_byte);
// errval is 0 if success, or -(error_code) if error.
if (errval == 0 || errval != -ENOMEM)
return 0;
}
USED(v);
USED(n);
return 1;
}
void*
runtime·SysAlloc(uintptr n)
{
void *p;
mstats.sys += n;
p = runtime·mmap(nil, n, PROT_READ|PROT_WRITE|PROT_EXEC, 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);
}
return nil;
}
return p;
}
void
runtime·SysUnused(void *v, uintptr n)
{
USED(v);
USED(n);
// TODO(rsc): call madvise 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
// and check the assumption in SysMap.
if(sizeof(void*) == 8)
return v;
p = runtime·mmap(v, n, PROT_NONE, MAP_ANON|MAP_PRIVATE, -1, 0);
if(p < (void*)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) {
p = runtime·mmap(v, n, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_ANON|MAP_PRIVATE, -1, 0);
if(p != v && addrspace_free(v, n)) {
// On some systems, mmap ignores v without
// MAP_FIXED, so retry if the address space is free.
p = runtime·mmap(v, n, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_ANON|MAP_FIXED|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|PROT_EXEC, 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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