forked from firedancer-io/radiance
/
interpreter.go
568 lines (543 loc) · 15.1 KB
/
interpreter.go
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package sbf
import (
"fmt"
"math"
"math/bits"
"unsafe"
)
// Interpreter implements the SBF core in pure Go.
type Interpreter struct {
textVA uint64
text []byte
ro []byte
stack Stack
heap []byte
input []byte
entry uint64
cuMax int
syscalls map[uint32]Syscall
funcs map[uint32]int64
vmContext any
trace TraceSink
}
type TraceSink interface {
Printf(format string, v ...any)
}
// NewInterpreter creates a new interpreter instance for a program execution.
//
// The caller must create a new interpreter object for every new execution.
// In other words, Run may only be called once per interpreter.
func NewInterpreter(p *Program, opts *VMOpts) *Interpreter {
return &Interpreter{
textVA: p.TextVA,
text: p.Text,
ro: p.RO,
stack: NewStack(),
heap: make([]byte, opts.HeapSize),
input: opts.Input,
entry: p.Entrypoint,
cuMax: opts.MaxCU,
syscalls: opts.Syscalls,
funcs: p.Funcs,
vmContext: opts.Context,
trace: opts.Tracer,
}
}
// Run executes the program.
//
// This function may panic given code that doesn't pass the static verifier.
func (ip *Interpreter) Run() (err error) {
var r [11]uint64
r[1] = VaddrInput
r[10] = ip.stack.GetFramePtr()
// TODO frame pointer
pc := int64(ip.entry)
cuLeft := int(ip.cuMax)
// Design notes
// - The interpreter is deliberately implemented in a single big loop,
// to give the compiler more creative liberties, and avoid escaping hot data to the heap.
// - uint64(int32(x)) performs sign extension. Most ALU64 instructions make use of this.
// - The static verifier imposes invariants on the bytecode.
// The interpreter may panic when it notices these invariants are violated (e.g. invalid opcode)
mainLoop:
for i := 0; true; i++ {
// Fetch
ins := ip.getSlot(pc)
if ip.trace != nil {
ip.trace.Printf("% 5d [%016x, %016x, %016x, %016x, %016x, %016x, %016x, %016x, %016x, %016x, %016x] % 5d: %s",
i, r[0], r[1], r[2], r[3], r[4], r[5], r[6], r[7], r[8], r[9], r[10], pc+29 /*todo weird offset*/, disassemble(ins /*todo*/, 0))
}
// Execute
switch ins.Op() {
case OpLdxb:
vma := uint64(int64(r[ins.Src()]) + int64(ins.Off()))
var v uint8
v, err = ip.Read8(vma)
r[ins.Dst()] = uint64(v)
case OpLdxh:
vma := uint64(int64(r[ins.Src()]) + int64(ins.Off()))
var v uint16
v, err = ip.Read16(vma)
r[ins.Dst()] = uint64(v)
case OpLdxw:
vma := uint64(int64(r[ins.Src()]) + int64(ins.Off()))
var v uint32
v, err = ip.Read32(vma)
r[ins.Dst()] = uint64(v)
case OpLdxdw:
vma := uint64(int64(r[ins.Src()]) + int64(ins.Off()))
r[ins.Dst()], err = ip.Read64(vma)
case OpStb:
vma := uint64(int64(r[ins.Dst()]) + int64(ins.Off()))
err = ip.Write8(vma, uint8(ins.Uimm()))
case OpSth:
vma := uint64(int64(r[ins.Dst()]) + int64(ins.Off()))
err = ip.Write16(vma, uint16(ins.Uimm()))
case OpStw:
vma := uint64(int64(r[ins.Dst()]) + int64(ins.Off()))
err = ip.Write32(vma, ins.Uimm())
case OpStdw:
vma := uint64(int64(r[ins.Dst()]) + int64(ins.Off()))
err = ip.Write64(vma, uint64(ins.Imm()))
case OpStxb:
vma := uint64(int64(r[ins.Dst()]) + int64(ins.Off()))
err = ip.Write8(vma, uint8(r[ins.Src()]))
case OpStxh:
vma := uint64(int64(r[ins.Dst()]) + int64(ins.Off()))
err = ip.Write16(vma, uint16(r[ins.Src()]))
case OpStxw:
vma := uint64(int64(r[ins.Dst()]) + int64(ins.Off()))
err = ip.Write32(vma, uint32(r[ins.Src()]))
case OpStxdw:
vma := uint64(int64(r[ins.Dst()]) + int64(ins.Off()))
err = ip.Write64(vma, r[ins.Src()])
case OpAdd32Imm:
r[ins.Dst()] = uint64(int32(r[ins.Dst()]) + ins.Imm())
case OpAdd32Reg:
r[ins.Dst()] = uint64(int32(r[ins.Dst()]) + int32(r[ins.Src()]))
case OpAdd64Imm:
r[ins.Dst()] += uint64(ins.Imm())
case OpAdd64Reg:
r[ins.Dst()] += r[ins.Src()]
case OpSub32Imm:
r[ins.Dst()] = uint64(int32(r[ins.Dst()]) - ins.Imm())
case OpSub32Reg:
r[ins.Dst()] = uint64(int32(r[ins.Dst()]) - int32(r[ins.Src()]))
case OpSub64Imm:
r[ins.Dst()] -= uint64(ins.Imm())
case OpSub64Reg:
r[ins.Dst()] -= r[ins.Src()]
case OpMul32Imm:
r[ins.Dst()] = uint64(int32(r[ins.Dst()]) * ins.Imm())
case OpMul32Reg:
r[ins.Dst()] = uint64(int32(r[ins.Dst()]) * int32(r[ins.Src()]))
case OpMul64Imm:
r[ins.Dst()] *= uint64(ins.Imm())
case OpMul64Reg:
r[ins.Dst()] *= r[ins.Src()]
case OpDiv32Imm:
r[ins.Dst()] = uint64(uint32(r[ins.Dst()]) / ins.Uimm())
case OpDiv32Reg:
if src := uint32(r[ins.Src()]); src != 0 {
r[ins.Dst()] = uint64(uint32(r[ins.Dst()]) / src)
} else {
return ExcDivideByZero
}
case OpDiv64Imm:
r[ins.Dst()] /= uint64(ins.Imm())
case OpDiv64Reg:
if src := r[ins.Src()]; src != 0 {
r[ins.Dst()] /= src
} else {
err = ExcDivideByZero
}
case OpSdiv32Imm:
if int32(r[ins.Dst()]) == math.MinInt32 && ins.Imm() == -1 {
err = ExcDivideOverflow
}
r[ins.Dst()] = uint64(int32(r[ins.Dst()]) / ins.Imm())
case OpSdiv32Reg:
if src := int32(r[ins.Src()]); src != 0 {
if int32(r[ins.Dst()]) == math.MinInt32 && src == -1 {
err = ExcDivideOverflow
}
r[ins.Dst()] = uint64(int32(r[ins.Dst()]) / src)
} else {
err = ExcDivideByZero
}
case OpSdiv64Imm:
if int64(r[ins.Dst()]) == math.MinInt64 && ins.Imm() == -1 {
err = ExcDivideOverflow
}
r[ins.Dst()] = uint64(int64(r[ins.Dst()]) / int64(ins.Imm()))
case OpSdiv64Reg:
if src := int64(r[ins.Src()]); src != 0 {
if int64(r[ins.Dst()]) == math.MinInt64 && src == -1 {
err = ExcDivideOverflow
}
r[ins.Dst()] = uint64(int64(r[ins.Dst()]) / src)
} else {
err = ExcDivideByZero
}
case OpOr32Imm:
r[ins.Dst()] = uint64(uint32(r[ins.Dst()]) | ins.Uimm())
case OpOr32Reg:
r[ins.Dst()] = uint64(uint32(r[ins.Dst()]) | uint32(r[ins.Src()]))
case OpOr64Imm:
r[ins.Dst()] |= uint64(ins.Imm())
case OpOr64Reg:
r[ins.Dst()] |= r[ins.Src()]
case OpAnd32Imm:
r[ins.Dst()] = uint64(uint32(r[ins.Dst()]) & ins.Uimm())
case OpAnd32Reg:
r[ins.Dst()] = uint64(uint32(r[ins.Dst()]) & uint32(r[ins.Src()]))
case OpAnd64Imm:
r[ins.Dst()] &= uint64(ins.Imm())
case OpAnd64Reg:
r[ins.Dst()] &= r[ins.Src()]
case OpLsh32Imm:
r[ins.Dst()] = uint64(uint32(r[ins.Dst()]) << ins.Uimm())
case OpLsh32Reg:
r[ins.Dst()] = uint64(uint32(r[ins.Dst()]) << uint32(r[ins.Src()]&0x1f))
case OpLsh64Imm:
r[ins.Dst()] <<= uint64(ins.Imm())
case OpLsh64Reg:
r[ins.Dst()] <<= r[ins.Src()] & 0x3f
case OpRsh32Imm:
r[ins.Dst()] = uint64(uint32(r[ins.Dst()]) >> ins.Uimm())
case OpRsh32Reg:
r[ins.Dst()] = uint64(uint32(r[ins.Dst()]) >> uint32(r[ins.Src()]&0x1f))
case OpRsh64Imm:
r[ins.Dst()] >>= uint64(ins.Imm())
case OpRsh64Reg:
r[ins.Dst()] >>= r[ins.Src()] & 0x3f
case OpNeg32:
r[ins.Dst()] = uint64(-int32(r[ins.Dst()]))
case OpNeg64:
r[ins.Dst()] = uint64(-int64(r[ins.Dst()]))
case OpMod32Imm:
r[ins.Dst()] = uint64(uint32(r[ins.Dst()]) % ins.Uimm())
case OpMod32Reg:
if src := uint32(r[ins.Src()]); src != 0 {
r[ins.Dst()] = uint64(uint32(r[ins.Dst()]) % src)
} else {
err = ExcDivideByZero
}
case OpMod64Imm:
r[ins.Dst()] %= uint64(ins.Imm())
case OpMod64Reg:
if src := r[ins.Src()]; src != 0 {
r[ins.Dst()] %= src
} else {
err = ExcDivideByZero
}
case OpXor32Imm:
r[ins.Dst()] = uint64(uint32(r[ins.Dst()]) ^ ins.Uimm())
case OpXor32Reg:
r[ins.Dst()] = uint64(uint32(r[ins.Dst()]) ^ uint32(r[ins.Src()]))
case OpXor64Imm:
r[ins.Dst()] ^= uint64(ins.Imm())
case OpXor64Reg:
r[ins.Dst()] ^= r[ins.Src()]
case OpMov32Imm:
r[ins.Dst()] = uint64(ins.Uimm())
case OpMov32Reg:
r[ins.Dst()] = r[ins.Src()] & math.MaxUint32
case OpMov64Imm:
r[ins.Dst()] = uint64(ins.Imm())
case OpMov64Reg:
r[ins.Dst()] = r[ins.Src()]
case OpArsh32Imm:
r[ins.Dst()] = uint64(int32(r[ins.Dst()]) >> ins.Uimm())
case OpArsh32Reg:
r[ins.Dst()] = uint64(int32(r[ins.Dst()]) >> uint32(r[ins.Src()]&0x1f))
case OpArsh64Imm:
r[ins.Dst()] = uint64(int64(r[ins.Dst()]) >> ins.Imm())
case OpArsh64Reg:
r[ins.Dst()] = uint64(int64(r[ins.Dst()]) >> (r[ins.Src()] & 0x3f))
case OpLe:
switch ins.Uimm() {
case 16:
r[ins.Dst()] &= math.MaxUint16
case 32:
r[ins.Dst()] &= math.MaxUint32
case 64:
r[ins.Dst()] &= math.MaxUint64
default:
panic("invalid le instruction")
}
case OpBe:
switch ins.Uimm() {
case 16:
r[ins.Dst()] = uint64(bits.ReverseBytes16(uint16(r[ins.Dst()])))
case 32:
r[ins.Dst()] = uint64(bits.ReverseBytes32(uint32(r[ins.Dst()])))
case 64:
r[ins.Dst()] = bits.ReverseBytes64(r[ins.Dst()])
default:
panic("invalid be instruction")
}
case OpLddw:
r[ins.Dst()] = uint64(ins.Uimm()) | (uint64(ip.getSlot(pc+1).Uimm()) << 32)
pc++
case OpJa:
pc += int64(ins.Off())
case OpJeqImm:
if r[ins.Dst()] == uint64(ins.Imm()) {
pc += int64(ins.Off())
}
case OpJeqReg:
if r[ins.Dst()] == r[ins.Src()] {
pc += int64(ins.Off())
}
case OpJgtImm:
if r[ins.Dst()] > uint64(ins.Imm()) {
pc += int64(ins.Off())
}
case OpJgtReg:
if r[ins.Dst()] > r[ins.Src()] {
pc += int64(ins.Off())
}
case OpJgeImm:
if r[ins.Dst()] >= uint64(ins.Imm()) {
pc += int64(ins.Off())
}
case OpJgeReg:
if r[ins.Dst()] >= r[ins.Src()] {
pc += int64(ins.Off())
}
case OpJltImm:
if r[ins.Dst()] < uint64(ins.Imm()) {
pc += int64(ins.Off())
}
case OpJltReg:
if r[ins.Dst()] < r[ins.Src()] {
pc += int64(ins.Off())
}
case OpJleImm:
if r[ins.Dst()] <= uint64(ins.Imm()) {
pc += int64(ins.Off())
}
case OpJleReg:
if r[ins.Dst()] <= r[ins.Src()] {
pc += int64(ins.Off())
}
case OpJsetImm:
if r[ins.Dst()]&uint64(ins.Imm()) != 0 {
pc += int64(ins.Off())
}
case OpJsetReg:
if r[ins.Dst()]&r[ins.Src()] != 0 {
pc += int64(ins.Off())
}
case OpJneImm:
if r[ins.Dst()] != uint64(ins.Imm()) {
pc += int64(ins.Off())
}
case OpJneReg:
if r[ins.Dst()] != r[ins.Src()] {
pc += int64(ins.Off())
}
case OpJsgtImm:
if int64(r[ins.Dst()]) > int64(ins.Imm()) {
pc += int64(ins.Off())
}
case OpJsgtReg:
if int64(r[ins.Dst()]) > int64(r[ins.Src()]) {
pc += int64(ins.Off())
}
case OpJsgeImm:
if int64(r[ins.Dst()]) >= int64(ins.Imm()) {
pc += int64(ins.Off())
}
case OpJsgeReg:
if int64(r[ins.Dst()]) >= int64(r[ins.Src()]) {
pc += int64(ins.Off())
}
case OpJsltImm:
if int64(r[ins.Dst()]) < int64(ins.Imm()) {
pc += int64(ins.Off())
}
case OpJsltReg:
if int64(r[ins.Dst()]) < int64(r[ins.Src()]) {
pc += int64(ins.Off())
}
case OpJsleImm:
if int64(r[ins.Dst()]) <= int64(ins.Imm()) {
pc += int64(ins.Off())
}
case OpJsleReg:
if int64(r[ins.Dst()]) <= int64(r[ins.Src()]) {
pc += int64(ins.Off())
}
case OpCall:
// TODO use src reg hint
if sc, ok := ip.syscalls[ins.Uimm()]; ok {
r[0], cuLeft, err = sc.Invoke(ip, r[1], r[2], r[3], r[4], r[5], cuLeft)
} else if target, ok := ip.funcs[ins.Uimm()]; ok {
r[10], ok = ip.stack.Push((*[4]uint64)(r[6:10]), pc+1)
if !ok {
err = ExcCallDepth
}
pc = target - 1
} else {
err = ExcCallDest{ins.Uimm()}
}
case OpCallx:
target := r[ins.Uimm()]
target &= ^(uint64(0x7))
var ok bool
r[10], ok = ip.stack.Push((*[4]uint64)(r[6:10]), pc+1)
if !ok {
err = ExcCallDepth
}
if target < ip.textVA || target >= VaddrStack || target >= ip.textVA+uint64(len(ip.text)) {
err = NewExcBadAccess(target, 8, false, "jump out-of-bounds")
}
pc = int64((target-ip.textVA)/8) - 1
case OpExit:
var ok bool
r[10], pc, ok = ip.stack.Pop((*[4]uint64)(r[6:10]))
if !ok {
break mainLoop
}
pc--
default:
panic(fmt.Sprintf("unimplemented opcode %#02x", ins.Op()))
}
// Post execute
if cuLeft < 0 {
err = ExcOutOfCU
}
if err != nil {
exc := &Exception{
PC: pc,
Detail: err,
}
if IsLongIns(ins.Op()) {
exc.PC-- // fix reported PC
}
return exc
}
pc++
}
return nil
}
func (ip *Interpreter) getSlot(pc int64) Slot {
return GetSlot(ip.text[pc*SlotSize:])
}
func (ip *Interpreter) VMContext() any {
return ip.vmContext
}
func (ip *Interpreter) Translate(addr uint64, size uint32, write bool) (unsafe.Pointer, error) {
// TODO exhaustive testing against rbpf
// TODO review generated asm for performance
hi, lo := addr>>32, addr&math.MaxUint32
switch hi {
case VaddrProgram >> 32:
if write {
return nil, NewExcBadAccess(addr, size, write, "write to program")
}
if lo+uint64(size) >= uint64(len(ip.ro)) {
return nil, NewExcBadAccess(addr, size, write, "out-of-bounds program read")
}
return unsafe.Pointer(&ip.ro[lo]), nil
case VaddrStack >> 32:
mem := ip.stack.GetFrame(uint32(addr))
if uint32(len(mem)) < size {
return nil, NewExcBadAccess(addr, size, write, "out-of-bounds stack access")
}
return unsafe.Pointer(&mem[0]), nil
case VaddrHeap >> 32:
if lo+uint64(size) >= uint64(len(ip.heap)) {
return nil, NewExcBadAccess(addr, size, write, "out-of-bounds heap access")
}
return unsafe.Pointer(&ip.heap[lo]), nil
case VaddrInput >> 32:
if lo+uint64(size) >= uint64(len(ip.input)) {
return nil, NewExcBadAccess(addr, size, write, "out-of-bounds input access")
}
return unsafe.Pointer(&ip.input[lo]), nil
default:
return nil, NewExcBadAccess(addr, size, write, "unmapped region")
}
}
func (ip *Interpreter) Read(addr uint64, p []byte) error {
ptr, err := ip.Translate(addr, uint32(len(p)), false)
if err != nil {
return err
}
mem := unsafe.Slice((*uint8)(ptr), len(p))
copy(p, mem)
return nil
}
func (ip *Interpreter) Read8(addr uint64) (uint8, error) {
ptr, err := ip.Translate(addr, 1, false)
if err != nil {
return 0, err
}
return *(*uint8)(ptr), nil
}
// TODO is it safe and portable to deref unaligned integer types?
func (ip *Interpreter) Read16(addr uint64) (uint16, error) {
ptr, err := ip.Translate(addr, 2, false)
if err != nil {
return 0, err
}
return *(*uint16)(ptr), nil
}
func (ip *Interpreter) Read32(addr uint64) (uint32, error) {
ptr, err := ip.Translate(addr, 4, false)
if err != nil {
return 0, err
}
return *(*uint32)(ptr), nil
}
func (ip *Interpreter) Read64(addr uint64) (uint64, error) {
ptr, err := ip.Translate(addr, 8, false)
if err != nil {
return 0, err
}
return *(*uint64)(ptr), nil
}
func (ip *Interpreter) Write(addr uint64, p []byte) error {
ptr, err := ip.Translate(addr, uint32(len(p)), true)
if err != nil {
return err
}
mem := unsafe.Slice((*uint8)(ptr), len(p))
copy(mem, p)
return nil
}
func (ip *Interpreter) Write8(addr uint64, x uint8) error {
ptr, err := ip.Translate(addr, 1, true)
if err != nil {
return err
}
*(*uint8)(ptr) = x
return nil
}
func (ip *Interpreter) Write16(addr uint64, x uint16) error {
ptr, err := ip.Translate(addr, 2, true)
if err != nil {
return err
}
*(*uint16)(ptr) = x
return nil
}
func (ip *Interpreter) Write32(addr uint64, x uint32) error {
ptr, err := ip.Translate(addr, 4, true)
if err != nil {
return err
}
*(*uint32)(ptr) = x
return nil
}
func (ip *Interpreter) Write64(addr uint64, x uint64) error {
ptr, err := ip.Translate(addr, 8, false)
if err != nil {
return err
}
*(*uint64)(ptr) = x
return nil
}