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, err := mmap(nil, n, _PROT_READ|_PROT_WRITE, _MAP_ANON|_MAP_PRIVATE, -1, 0) 19 if err != 0 { 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, err := mmap(v, n, _PROT_NONE, _MAP_ANON|_MAP_PRIVATE, -1, 0) 55 if err != 0 { 56 return nil 57 } 58 *reserved = true 59 return p 60 } 61 62 const _sunosEAGAIN = 11 63 const _ENOMEM = 12 64 65 func sysMap(v unsafe.Pointer, n uintptr, reserved bool, sysStat *uint64) { 66 mSysStatInc(sysStat, n) 67 68 // On 64-bit, we don't actually have v reserved, so tread carefully. 69 if !reserved { 70 flags := int32(_MAP_ANON | _MAP_PRIVATE) 71 if GOOS == "dragonfly" { 72 // TODO(jsing): For some reason DragonFly seems to return 73 // memory at a different address than we requested, even when 74 // there should be no reason for it to do so. This can be 75 // avoided by using MAP_FIXED, but I'm not sure we should need 76 // to do this - we do not on other platforms. 77 flags |= _MAP_FIXED 78 } 79 p, err := mmap(v, n, _PROT_READ|_PROT_WRITE, flags, -1, 0) 80 if err == _ENOMEM || (GOOS == "solaris" && err == _sunosEAGAIN) { 81 throw("runtime: out of memory") 82 } 83 if p != v || err != 0 { 84 print("runtime: address space conflict: map(", v, ") = ", p, "(err ", err, ")\n") 85 throw("runtime: address space conflict") 86 } 87 return 88 } 89 90 p, err := mmap(v, n, _PROT_READ|_PROT_WRITE, _MAP_ANON|_MAP_FIXED|_MAP_PRIVATE, -1, 0) 91 if err == _ENOMEM || (GOOS == "solaris" && err == _sunosEAGAIN) { 92 throw("runtime: out of memory") 93 } 94 if p != v || err != 0 { 95 throw("runtime: cannot map pages in arena address space") 96 } 97 } 98
