| // Copyright 2014 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| //go:build amd64 || arm64 || mips64 || mips64le || ppc64 || ppc64le || riscv64 || s390x || wasm || arm64be || alpha || sparc64 || ia64 |
| |
| package runtime |
| |
| import "unsafe" |
| |
| const ( |
| // addrBits is the number of bits needed to represent a virtual address. |
| // |
| // See heapAddrBits for a table of address space sizes on |
| // various architectures. 48 bits is enough for all |
| // architectures except s390x. |
| // |
| // On AMD64, virtual addresses are 48-bit (or 57-bit) numbers sign extended to 64. |
| // We shift the address left 16 to eliminate the sign extended part and make |
| // room in the bottom for the count. |
| // |
| // On s390x, virtual addresses are 64-bit. There's not much we |
| // can do about this, so we just hope that the kernel doesn't |
| // get to really high addresses and panic if it does. |
| addrBits = 48 |
| |
| // In addition to the 16 bits taken from the top, we can take 3 from the |
| // bottom, because node must be pointer-aligned, giving a total of 19 bits |
| // of count. |
| cntBits = 64 - addrBits + 3 |
| |
| // On sparc64-linux, user addresses are 52-bit numbers sign extended to 64. |
| // We shift the address left 12 to eliminate the sign extended part and make |
| // room in the bottom for the count. |
| sparcLinuxAddrBits = 52 |
| sparcLinuxCntBits = 64 - sparcLinuxAddrBits + 3 |
| |
| // On IA64, the virtual address space is devided into 8 regions, with |
| // 52 address bits each (with 64k page size). |
| ia64AddrBits = 55 |
| ia64CntBits = 64 - ia64AddrBits + 3 |
| |
| // On AIX, 64-bit addresses are split into 36-bit segment number and 28-bit |
| // offset in segment. Segment numbers in the range 0x0A0000000-0x0AFFFFFFF(LSA) |
| // are available for mmap. |
| // We assume all lfnode addresses are from memory allocated with mmap. |
| // We use one bit to distinguish between the two ranges. |
| aixAddrBits = 57 |
| aixCntBits = 64 - aixAddrBits + 3 |
| ) |
| |
| func lfstackPack(node *lfnode, cnt uintptr) uint64 { |
| if GOARCH == "sparc64" && GOOS == "linux" { |
| return uint64(uintptr(unsafe.Pointer(node)))<<(64-sparcLinuxAddrBits) | uint64(cnt&(1<<sparcLinuxCntBits-1)) |
| } |
| if GOARCH == "ia64" { |
| // Top three bits are the region number |
| val := uint64(uintptr(unsafe.Pointer(node))) |
| return (val<<(64-ia64AddrBits))&(1<<(64-3)-1) | val&^(1<<(64-3)-1) | uint64(cnt&(1<<ia64CntBits-1)) |
| } |
| if GOARCH == "ppc64" && GOOS == "aix" { |
| return uint64(uintptr(unsafe.Pointer(node)))<<(64-aixAddrBits) | uint64(cnt&(1<<aixCntBits-1)) |
| } |
| return uint64(uintptr(unsafe.Pointer(node)))<<(64-addrBits) | uint64(cnt&(1<<cntBits-1)) |
| } |
| |
| func lfstackUnpack(val uint64) *lfnode { |
| if GOARCH == "amd64" || GOOS == "solaris" { |
| // amd64 or Solaris systems can place the stack above the VA hole, so we need to sign extend |
| // val before unpacking. |
| return (*lfnode)(unsafe.Pointer(uintptr(int64(val) >> cntBits << 3))) |
| } |
| if GOARCH == "sparc64" && GOOS == "linux" { |
| return (*lfnode)(unsafe.Pointer(uintptr(int64(val) >> sparcLinuxCntBits << 3))) |
| } |
| if GOARCH == "ia64" { |
| return (*lfnode)(unsafe.Pointer(uintptr(((val & (1<<(64-3) - 1)) >> ia64CntBits << 3) | val&^(1<<(64-3)-1)))) |
| } |
| if GOARCH == "ppc64" && GOOS == "aix" { |
| return (*lfnode)(unsafe.Pointer(uintptr((val >> aixCntBits << 3) | 0xa<<56))) |
| } |
| return (*lfnode)(unsafe.Pointer(uintptr(val >> cntBits << 3))) |
| } |