forked from go-delve/delve
/
registers.go
347 lines (300 loc) · 9.71 KB
/
registers.go
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package proc
import (
"bytes"
"encoding/binary"
"errors"
"fmt"
"math"
"os"
"strings"
)
// Registers is an interface for a generic register type. The
// interface encapsulates the generic values / actions
// we need independent of arch. The concrete register types
// will be different depending on OS/Arch.
type Registers interface {
PC() uint64
SP() uint64
BP() uint64
CX() uint64
TLS() uint64
// GAddr returns the address of the G variable if it is known, 0 and false otherwise
GAddr() (uint64, bool)
Get(int) (uint64, error)
Slice() []Register
// Save saves a copy of this object that will survive restarts
Save() SavedRegisters
}
type Register struct {
Name string
Bytes []byte
Value string
}
type SavedRegisters interface {
}
// AppendWordReg appends a word (16 bit) register to regs.
func AppendWordReg(regs []Register, name string, value uint16) []Register {
var buf bytes.Buffer
binary.Write(&buf, binary.LittleEndian, value)
return append(regs, Register{name, buf.Bytes(), fmt.Sprintf("%#04x", value)})
}
// AppendDwordReg appends a double word (32 bit) register to regs.
func AppendDwordReg(regs []Register, name string, value uint32) []Register {
var buf bytes.Buffer
binary.Write(&buf, binary.LittleEndian, value)
return append(regs, Register{name, buf.Bytes(), fmt.Sprintf("%#08x", value)})
}
// AppendQwordReg appends a quad word (64 bit) register to regs.
func AppendQwordReg(regs []Register, name string, value uint64) []Register {
var buf bytes.Buffer
binary.Write(&buf, binary.LittleEndian, value)
return append(regs, Register{name, buf.Bytes(), fmt.Sprintf("%#016x", value)})
}
func appendFlagReg(regs []Register, name string, value uint64, descr flagRegisterDescr, size int) []Register {
var buf bytes.Buffer
binary.Write(&buf, binary.LittleEndian, value)
return append(regs, Register{name, buf.Bytes()[:size], descr.Describe(value, size)})
}
// AppendEflagReg appends EFLAG register to regs.
func AppendEflagReg(regs []Register, name string, value uint64) []Register {
return appendFlagReg(regs, name, value, eflagsDescription, 64)
}
// AppendMxcsrReg appends MXCSR register to regs.
func AppendMxcsrReg(regs []Register, name string, value uint64) []Register {
return appendFlagReg(regs, name, value, mxcsrDescription, 32)
}
// AppendX87Reg appends a 80 bit float register to regs.
func AppendX87Reg(regs []Register, index int, exponent uint16, mantissa uint64) []Register {
var f float64
fset := false
const (
_SIGNBIT = 1 << 15
_EXP_BIAS = (1 << 14) - 1 // 2^(n-1) - 1 = 16383
_SPECIALEXP = (1 << 15) - 1 // all bits set
_HIGHBIT = 1 << 63
_QUIETBIT = 1 << 62
)
sign := 1.0
if exponent&_SIGNBIT != 0 {
sign = -1.0
}
exponent &= ^uint16(_SIGNBIT)
NaN := math.NaN()
Inf := math.Inf(+1)
switch exponent {
case 0:
switch {
case mantissa == 0:
f = sign * 0.0
fset = true
case mantissa&_HIGHBIT != 0:
f = NaN
fset = true
}
case _SPECIALEXP:
switch {
case mantissa&_HIGHBIT == 0:
f = sign * Inf
fset = true
default:
f = NaN // signaling NaN
fset = true
}
default:
if mantissa&_HIGHBIT == 0 {
f = NaN
fset = true
}
}
if !fset {
significand := float64(mantissa) / (1 << 63)
f = sign * math.Ldexp(significand, int(exponent-_EXP_BIAS))
}
var buf bytes.Buffer
binary.Write(&buf, binary.LittleEndian, exponent)
binary.Write(&buf, binary.LittleEndian, mantissa)
return append(regs, Register{fmt.Sprintf("ST(%d)", index), buf.Bytes(), fmt.Sprintf("%#04x%016x\t%g", exponent, mantissa, f)})
}
// AppendSSEReg appends a 256 bit SSE register to regs.
func AppendSSEReg(regs []Register, name string, xmm []byte) []Register {
buf := bytes.NewReader(xmm)
var out bytes.Buffer
var vi [16]uint8
for i := range vi {
binary.Read(buf, binary.LittleEndian, &vi[i])
}
fmt.Fprintf(&out, "0x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x", vi[15], vi[14], vi[13], vi[12], vi[11], vi[10], vi[9], vi[8], vi[7], vi[6], vi[5], vi[4], vi[3], vi[2], vi[1], vi[0])
fmt.Fprintf(&out, "\tv2_int={ %02x%02x%02x%02x%02x%02x%02x%02x %02x%02x%02x%02x%02x%02x%02x%02x }", vi[7], vi[6], vi[5], vi[4], vi[3], vi[2], vi[1], vi[0], vi[15], vi[14], vi[13], vi[12], vi[11], vi[10], vi[9], vi[8])
fmt.Fprintf(&out, "\tv4_int={ %02x%02x%02x%02x %02x%02x%02x%02x %02x%02x%02x%02x %02x%02x%02x%02x }", vi[3], vi[2], vi[1], vi[0], vi[7], vi[6], vi[5], vi[4], vi[11], vi[10], vi[9], vi[8], vi[15], vi[14], vi[13], vi[12])
fmt.Fprintf(&out, "\tv8_int={ %02x%02x %02x%02x %02x%02x %02x%02x %02x%02x %02x%02x %02x%02x %02x%02x }", vi[1], vi[0], vi[3], vi[2], vi[5], vi[4], vi[7], vi[6], vi[9], vi[8], vi[11], vi[10], vi[13], vi[12], vi[15], vi[14])
fmt.Fprintf(&out, "\tv16_int={ %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x }", vi[0], vi[1], vi[2], vi[3], vi[4], vi[5], vi[6], vi[7], vi[8], vi[9], vi[10], vi[11], vi[12], vi[13], vi[14], vi[15])
buf.Seek(0, os.SEEK_SET)
var v2 [2]float64
for i := range v2 {
binary.Read(buf, binary.LittleEndian, &v2[i])
}
fmt.Fprintf(&out, "\tv2_float={ %g %g }", v2[0], v2[1])
buf.Seek(0, os.SEEK_SET)
var v4 [4]float32
for i := range v4 {
binary.Read(buf, binary.LittleEndian, &v4[i])
}
fmt.Fprintf(&out, "\tv4_float={ %g %g %g %g }", v4[0], v4[1], v4[2], v4[3])
return append(regs, Register{name, xmm, out.String()})
}
var UnknownRegisterError = errors.New("unknown register")
type flagRegisterDescr []flagDescr
type flagDescr struct {
name string
mask uint64
}
var mxcsrDescription flagRegisterDescr = []flagDescr{
{"FZ", 1 << 15},
{"RZ/RN", 1<<14 | 1<<13},
{"PM", 1 << 12},
{"UM", 1 << 11},
{"OM", 1 << 10},
{"ZM", 1 << 9},
{"DM", 1 << 8},
{"IM", 1 << 7},
{"DAZ", 1 << 6},
{"PE", 1 << 5},
{"UE", 1 << 4},
{"OE", 1 << 3},
{"ZE", 1 << 2},
{"DE", 1 << 1},
{"IE", 1 << 0},
}
var eflagsDescription flagRegisterDescr = []flagDescr{
{"CF", 1 << 0},
{"", 1 << 1},
{"PF", 1 << 2},
{"AF", 1 << 4},
{"ZF", 1 << 6},
{"SF", 1 << 7},
{"TF", 1 << 8},
{"IF", 1 << 9},
{"DF", 1 << 10},
{"OF", 1 << 11},
{"IOPL", 1<<12 | 1<<13},
{"NT", 1 << 14},
{"RF", 1 << 16},
{"VM", 1 << 17},
{"AC", 1 << 18},
{"VIF", 1 << 19},
{"VIP", 1 << 20},
{"ID", 1 << 21},
}
func (descr flagRegisterDescr) Mask() uint64 {
var r uint64
for _, f := range descr {
r = r | f.mask
}
return r
}
func (descr flagRegisterDescr) Describe(reg uint64, bitsize int) string {
var r []string
for _, f := range descr {
if f.name == "" {
continue
}
// rbm is f.mask with only the right-most bit set:
// 0001 1100 -> 0000 0100
rbm := f.mask & -f.mask
if rbm == f.mask {
if reg&f.mask != 0 {
r = append(r, f.name)
}
} else {
x := (reg & f.mask) >> uint64(math.Log2(float64(rbm)))
r = append(r, fmt.Sprintf("%s=%x", f.name, x))
}
}
if reg & ^descr.Mask() != 0 {
r = append(r, fmt.Sprintf("unknown_flags=%x", reg&^descr.Mask()))
}
return fmt.Sprintf("%#0*x\t[%s]", bitsize/4, reg, strings.Join(r, " "))
}
// tracks user_fpregs_struct in /usr/include/x86_64-linux-gnu/sys/user.h
type PtraceFpRegs struct {
Cwd uint16
Swd uint16
Ftw uint16
Fop uint16
Rip uint64
Rdp uint64
Mxcsr uint32
MxcrMask uint32
StSpace [32]uint32
XmmSpace [256]byte
Padding [24]uint32
}
// LinuxX86Xstate represents amd64 XSAVE area. See Section 13.1 (and
// following) of Intel® 64 and IA-32 Architectures Software Developer’s
// Manual, Volume 1: Basic Architecture.
type LinuxX86Xstate struct {
PtraceFpRegs
Xsave []byte // raw xsave area
AvxState bool // contains AVX state
YmmSpace [256]byte
}
// Decode decodes an XSAVE area to a list of name/value pairs of registers.
func (xsave *LinuxX86Xstate) Decode() (regs []Register) {
// x87 registers
regs = AppendWordReg(regs, "CW", xsave.Cwd)
regs = AppendWordReg(regs, "SW", xsave.Swd)
regs = AppendWordReg(regs, "TW", xsave.Ftw)
regs = AppendWordReg(regs, "FOP", xsave.Fop)
regs = AppendQwordReg(regs, "FIP", xsave.Rip)
regs = AppendQwordReg(regs, "FDP", xsave.Rdp)
for i := 0; i < len(xsave.StSpace); i += 4 {
regs = AppendX87Reg(regs, i/4, uint16(xsave.StSpace[i+2]), uint64(xsave.StSpace[i+1])<<32|uint64(xsave.StSpace[i]))
}
// SSE registers
regs = AppendMxcsrReg(regs, "MXCSR", uint64(xsave.Mxcsr))
regs = AppendDwordReg(regs, "MXCSR_MASK", xsave.MxcrMask)
for i := 0; i < len(xsave.XmmSpace); i += 16 {
regs = AppendSSEReg(regs, fmt.Sprintf("XMM%d", i/16), xsave.XmmSpace[i:i+16])
if xsave.AvxState {
regs = AppendSSEReg(regs, fmt.Sprintf("YMM%d", i/16), xsave.YmmSpace[i:i+16])
}
}
return
}
const (
_XSAVE_HEADER_START = 512
_XSAVE_HEADER_LEN = 64
_XSAVE_EXTENDED_REGION_START = 576
_XSAVE_SSE_REGION_LEN = 416
)
// LinuxX86XstateRead reads a byte array containing an XSAVE area into regset.
// If readLegacy is true regset.PtraceFpRegs will be filled with the
// contents of the legacy region of the XSAVE area.
// See Section 13.1 (and following) of Intel® 64 and IA-32 Architectures
// Software Developer’s Manual, Volume 1: Basic Architecture.
func LinuxX86XstateRead(xstateargs []byte, readLegacy bool, regset *LinuxX86Xstate) error {
if _XSAVE_HEADER_START+_XSAVE_HEADER_LEN >= len(xstateargs) {
return nil
}
if readLegacy {
rdr := bytes.NewReader(xstateargs[:_XSAVE_HEADER_START])
if err := binary.Read(rdr, binary.LittleEndian, ®set.PtraceFpRegs); err != nil {
return err
}
}
xsaveheader := xstateargs[_XSAVE_HEADER_START : _XSAVE_HEADER_START+_XSAVE_HEADER_LEN]
xstate_bv := binary.LittleEndian.Uint64(xsaveheader[0:8])
xcomp_bv := binary.LittleEndian.Uint64(xsaveheader[8:16])
if xcomp_bv&(1<<63) != 0 {
// compact format not supported
return nil
}
if xstate_bv&(1<<2) == 0 {
// AVX state not present
return nil
}
avxstate := xstateargs[_XSAVE_EXTENDED_REGION_START:]
regset.AvxState = true
copy(regset.YmmSpace[:], avxstate[:len(regset.YmmSpace)])
return nil
}