| // 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, |
| EACCES = 13, |
| }; |
| |
| static int32 |
| addrspace_free(void *v, uintptr n) |
| { |
| int32 errval; |
| uintptr chunk; |
| uintptr off; |
| |
| // NOTE: vec must be just 1 byte long here. |
| // Mincore returns ENOMEM if any of the pages are unmapped, |
| // but we want to know that all of the pages are unmapped. |
| // To make these the same, we can only ask about one page |
| // at a time. See golang.org/issue/7476. |
| static byte vec[1]; |
| |
| 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); |
| // ENOMEM means unmapped, which is what we want. |
| // Anything else we assume means the pages are mapped. |
| if (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, uint64 *stat) |
| { |
| void *p; |
| |
| 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; |
| } |
| runtime·xadd64(stat, n); |
| return p; |
| } |
| |
| void |
| runtime·SysUnused(void *v, uintptr n) |
| { |
| runtime·madvise(v, n, MADV_DONTNEED); |
| } |
| |
| void |
| runtime·SysUsed(void *v, uintptr n) |
| { |
| USED(v); |
| USED(n); |
| } |
| |
| void |
| runtime·SysFree(void *v, uintptr n, uint64 *stat) |
| { |
| runtime·xadd64(stat, -(uint64)n); |
| runtime·munmap(v, n); |
| } |
| |
| void |
| runtime·SysFault(void *v, uintptr n) |
| { |
| runtime·mmap(v, n, PROT_NONE, MAP_ANON|MAP_PRIVATE|MAP_FIXED, -1, 0); |
| } |
| |
| void* |
| runtime·SysReserve(void *v, uintptr n, bool *reserved) |
| { |
| 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 && n > 1LL<<32) { |
| p = mmap_fixed(v, 64<<10, PROT_NONE, MAP_ANON|MAP_PRIVATE, -1, 0); |
| if (p != v) { |
| if(p >= (void*)4096) |
| runtime·munmap(p, 64<<10); |
| return nil; |
| } |
| runtime·munmap(p, 64<<10); |
| *reserved = false; |
| return v; |
| } |
| |
| p = runtime·mmap(v, n, PROT_NONE, MAP_ANON|MAP_PRIVATE, -1, 0); |
| if((uintptr)p < 4096) |
| return nil; |
| *reserved = true; |
| return p; |
| } |
| |
| void |
| runtime·SysMap(void *v, uintptr n, bool reserved, uint64 *stat) |
| { |
| void *p; |
| |
| runtime·xadd64(stat, n); |
| |
| // On 64-bit, we don't actually have v reserved, so tread carefully. |
| if(!reserved) { |
| 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"); |
| } |