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