1// Copyright 2014 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 amd64 arm64 mips64 mips64le ppc64 ppc64le riscv64 s390x wasm arm64be alpha sparc64 ia64 6 7package runtime 8 9import "unsafe" 10 11const ( 12 // addrBits is the number of bits needed to represent a virtual address. 13 // 14 // See heapAddrBits for a table of address space sizes on 15 // various architectures. 48 bits is enough for all 16 // architectures except s390x. 17 // 18 // On AMD64, virtual addresses are 48-bit (or 57-bit) numbers sign extended to 64. 19 // We shift the address left 16 to eliminate the sign extended part and make 20 // room in the bottom for the count. 21 // 22 // On s390x, virtual addresses are 64-bit. There's not much we 23 // can do about this, so we just hope that the kernel doesn't 24 // get to really high addresses and panic if it does. 25 addrBits = 48 26 27 // In addition to the 16 bits taken from the top, we can take 3 from the 28 // bottom, because node must be pointer-aligned, giving a total of 19 bits 29 // of count. 30 cntBits = 64 - addrBits + 3 31 32 // On sparc64-linux, user addresses are 52-bit numbers sign extended to 64. 33 // We shift the address left 12 to eliminate the sign extended part and make 34 // room in the bottom for the count. 35 sparcLinuxAddrBits = 52 36 sparcLinuxCntBits = 64 - sparcLinuxAddrBits + 3 37 38 // On IA64, the virtual address space is devided into 8 regions, with 39 // 52 address bits each (with 64k page size). 40 ia64AddrBits = 55 41 ia64CntBits = 64 - ia64AddrBits + 3 42 43 // On AIX, 64-bit addresses are split into 36-bit segment number and 28-bit 44 // offset in segment. Segment numbers in the range 0x0A0000000-0x0AFFFFFFF(LSA) 45 // are available for mmap. 46 // We assume all lfnode addresses are from memory allocated with mmap. 47 // We use one bit to distinguish between the two ranges. 48 aixAddrBits = 57 49 aixCntBits = 64 - aixAddrBits + 3 50) 51 52func lfstackPack(node *lfnode, cnt uintptr) uint64 { 53 if GOARCH == "sparc64" && GOOS == "linux" { 54 return uint64(uintptr(unsafe.Pointer(node)))<<(64-sparcLinuxAddrBits) | uint64(cnt&(1<<sparcLinuxCntBits-1)) 55 } 56 if GOARCH == "ia64" { 57 // Top three bits are the region number 58 val := uint64(uintptr(unsafe.Pointer(node))) 59 return (val<<(64-ia64AddrBits))&(1<<(64-3)-1) | val&^(1<<(64-3)-1) | uint64(cnt&(1<<ia64CntBits-1)) 60 } 61 if GOARCH == "ppc64" && GOOS == "aix" { 62 return uint64(uintptr(unsafe.Pointer(node)))<<(64-aixAddrBits) | uint64(cnt&(1<<aixCntBits-1)) 63 } 64 return uint64(uintptr(unsafe.Pointer(node)))<<(64-addrBits) | uint64(cnt&(1<<cntBits-1)) 65} 66 67func lfstackUnpack(val uint64) *lfnode { 68 if GOARCH == "amd64" || GOOS == "solaris" { 69 // amd64 or Solaris systems can place the stack above the VA hole, so we need to sign extend 70 // val before unpacking. 71 return (*lfnode)(unsafe.Pointer(uintptr(int64(val) >> cntBits << 3))) 72 } 73 if GOARCH == "sparc64" && GOOS == "linux" { 74 return (*lfnode)(unsafe.Pointer(uintptr(int64(val) >> sparcLinuxCntBits << 3))) 75 } 76 if GOARCH == "ia64" { 77 return (*lfnode)(unsafe.Pointer(uintptr(((val & (1<<(64-3) - 1)) >> ia64CntBits << 3) | val&^(1<<(64-3)-1)))) 78 } 79 if GOARCH == "ppc64" && GOOS == "aix" { 80 return (*lfnode)(unsafe.Pointer(uintptr((val >> aixCntBits << 3) | 0xa<<56))) 81 } 82 return (*lfnode)(unsafe.Pointer(uintptr(val >> cntBits << 3))) 83} 84