github.com/zach-klippenstein/go@v0.0.0-20150108044943-fcfbeb3adf58/src/runtime/mem_bsd.go (about) 1 // Copyright 2010 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 // +build dragonfly freebsd nacl netbsd openbsd solaris 6 7 package runtime 8 9 import "unsafe" 10 11 //go:nosplit 12 func sysAlloc(n uintptr, stat *uint64) unsafe.Pointer { 13 v := unsafe.Pointer(mmap(nil, n, _PROT_READ|_PROT_WRITE, _MAP_ANON|_MAP_PRIVATE, -1, 0)) 14 if uintptr(v) < 4096 { 15 return nil 16 } 17 xadd64(stat, int64(n)) 18 return v 19 } 20 21 func sysUnused(v unsafe.Pointer, n uintptr) { 22 madvise(v, n, _MADV_FREE) 23 } 24 25 func sysUsed(v unsafe.Pointer, n uintptr) { 26 } 27 28 func sysFree(v unsafe.Pointer, n uintptr, stat *uint64) { 29 xadd64(stat, -int64(n)) 30 munmap(v, n) 31 } 32 33 func sysFault(v unsafe.Pointer, n uintptr) { 34 mmap(v, n, _PROT_NONE, _MAP_ANON|_MAP_PRIVATE|_MAP_FIXED, -1, 0) 35 } 36 37 func sysReserve(v unsafe.Pointer, n uintptr, reserved *bool) unsafe.Pointer { 38 // On 64-bit, people with ulimit -v set complain if we reserve too 39 // much address space. Instead, assume that the reservation is okay 40 // and check the assumption in SysMap. 41 if ptrSize == 8 && uint64(n) > 1<<32 || goos_nacl != 0 { 42 *reserved = false 43 return v 44 } 45 46 p := unsafe.Pointer(mmap(v, n, _PROT_NONE, _MAP_ANON|_MAP_PRIVATE, -1, 0)) 47 if uintptr(p) < 4096 { 48 return nil 49 } 50 *reserved = true 51 return p 52 } 53 54 func sysMap(v unsafe.Pointer, n uintptr, reserved bool, stat *uint64) { 55 const _ENOMEM = 12 56 57 xadd64(stat, int64(n)) 58 59 // On 64-bit, we don't actually have v reserved, so tread carefully. 60 if !reserved { 61 flags := int32(_MAP_ANON | _MAP_PRIVATE) 62 if GOOS == "dragonfly" { 63 // TODO(jsing): For some reason DragonFly seems to return 64 // memory at a different address than we requested, even when 65 // there should be no reason for it to do so. This can be 66 // avoided by using MAP_FIXED, but I'm not sure we should need 67 // to do this - we do not on other platforms. 68 flags |= _MAP_FIXED 69 } 70 p := mmap(v, n, _PROT_READ|_PROT_WRITE, flags, -1, 0) 71 if uintptr(p) == _ENOMEM { 72 throw("runtime: out of memory") 73 } 74 if p != v { 75 print("runtime: address space conflict: map(", v, ") = ", p, "\n") 76 throw("runtime: address space conflict") 77 } 78 return 79 } 80 81 p := mmap(v, n, _PROT_READ|_PROT_WRITE, _MAP_ANON|_MAP_FIXED|_MAP_PRIVATE, -1, 0) 82 if uintptr(p) == _ENOMEM { 83 throw("runtime: out of memory") 84 } 85 if p != v { 86 throw("runtime: cannot map pages in arena address space") 87 } 88 }