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 ( 10 "runtime/internal/sys" 11 "unsafe" 12 ) 13 14 // Don't split the stack as this function may be invoked without a valid G, 15 // which prevents us from allocating more stack. 16 //go:nosplit 17 func sysAlloc(n uintptr, sysStat *uint64) unsafe.Pointer { 18 v := mmap(nil, n, _PROT_READ|_PROT_WRITE, _MAP_ANON|_MAP_PRIVATE, -1, 0) 19 if uintptr(v) < 4096 { 20 return nil 21 } 22 mSysStatInc(sysStat, n) 23 return v 24 } 25 26 func sysUnused(v unsafe.Pointer, n uintptr) { 27 madvise(v, n, _MADV_FREE) 28 } 29 30 func sysUsed(v unsafe.Pointer, n uintptr) { 31 } 32 33 // Don't split the stack as this function may be invoked without a valid G, 34 // which prevents us from allocating more stack. 35 //go:nosplit 36 func sysFree(v unsafe.Pointer, n uintptr, sysStat *uint64) { 37 mSysStatDec(sysStat, n) 38 munmap(v, n) 39 } 40 41 func sysFault(v unsafe.Pointer, n uintptr) { 42 mmap(v, n, _PROT_NONE, _MAP_ANON|_MAP_PRIVATE|_MAP_FIXED, -1, 0) 43 } 44 45 func sysReserve(v unsafe.Pointer, n uintptr, reserved *bool) unsafe.Pointer { 46 // On 64-bit, people with ulimit -v set complain if we reserve too 47 // much address space. Instead, assume that the reservation is okay 48 // and check the assumption in SysMap. 49 if sys.PtrSize == 8 && uint64(n) > 1<<32 || sys.GoosNacl != 0 { 50 *reserved = false 51 return v 52 } 53 54 p := mmap(v, n, _PROT_NONE, _MAP_ANON|_MAP_PRIVATE, -1, 0) 55 if uintptr(p) < 4096 { 56 return nil 57 } 58 *reserved = true 59 return p 60 } 61 62 const _ENOMEM = 12 63 64 func sysMap(v unsafe.Pointer, n uintptr, reserved bool, sysStat *uint64) { 65 mSysStatInc(sysStat, n) 66 67 // On 64-bit, we don't actually have v reserved, so tread carefully. 68 if !reserved { 69 flags := int32(_MAP_ANON | _MAP_PRIVATE) 70 if GOOS == "dragonfly" { 71 // TODO(jsing): For some reason DragonFly seems to return 72 // memory at a different address than we requested, even when 73 // there should be no reason for it to do so. This can be 74 // avoided by using MAP_FIXED, but I'm not sure we should need 75 // to do this - we do not on other platforms. 76 flags |= _MAP_FIXED 77 } 78 p := mmap(v, n, _PROT_READ|_PROT_WRITE, flags, -1, 0) 79 if uintptr(p) == _ENOMEM { 80 throw("runtime: out of memory") 81 } 82 if p != v { 83 print("runtime: address space conflict: map(", v, ") = ", p, "\n") 84 throw("runtime: address space conflict") 85 } 86 return 87 } 88 89 p := mmap(v, n, _PROT_READ|_PROT_WRITE, _MAP_ANON|_MAP_FIXED|_MAP_PRIVATE, -1, 0) 90 if uintptr(p) == _ENOMEM { 91 throw("runtime: out of memory") 92 } 93 if p != v { 94 throw("runtime: cannot map pages in arena address space") 95 } 96 } 97
