package asm
//go:generate stringer -output load_store_string.go -type=Mode,Size
// Mode for load and store operations
//
// msb lsb
// +---+--+---+
// |MDE|sz|cls|
// +---+--+---+
type Mode uint8
const modeMask OpCode = 0xe0
const (
// InvalidMode is returned by getters when invoked
// on non load / store OpCodes
InvalidMode Mode = 0xff
// ImmMode - immediate value
ImmMode Mode = 0x00
// AbsMode - immediate value + offset
AbsMode Mode = 0x20
// IndMode - indirect (imm+src)
IndMode Mode = 0x40
// MemMode - load from memory
MemMode Mode = 0x60
// XAddMode - add atomically across processors.
XAddMode Mode = 0xc0
)
// Size of load and store operations
//
// msb lsb
// +---+--+---+
// |mde|SZ|cls|
// +---+--+---+
type Size uint8
const sizeMask OpCode = 0x18
const (
// InvalidSize is returned by getters when invoked
// on non load / store OpCodes
InvalidSize Size = 0xff
// DWord - double word; 64 bits
DWord Size = 0x18
// Word - word; 32 bits
Word Size = 0x00
// Half - half-word; 16 bits
Half Size = 0x08
// Byte - byte; 8 bits
Byte Size = 0x10
)
// Sizeof returns the size in bytes.
func (s Size) Sizeof() int {
switch s {
case DWord:
return 8
case Word:
return 4
case Half:
return 2
case Byte:
return 1
default:
return -1
}
}
// LoadMemOp returns the OpCode to load a value of given size from memory.
func LoadMemOp(size Size) OpCode {
return OpCode(LdXClass).SetMode(MemMode).SetSize(size)
}
// LoadMem emits `dst = *(size *)(src + offset)`.
func LoadMem(dst, src Register, offset int16, size Size) Instruction {
return Instruction{
OpCode: LoadMemOp(size),
Dst: dst,
Src: src,
Offset: offset,
}
}
// LoadImmOp returns the OpCode to load an immediate of given size.
//
// As of kernel 4.20, only DWord size is accepted.
func LoadImmOp(size Size) OpCode {
return OpCode(LdClass).SetMode(ImmMode).SetSize(size)
}
// LoadImm emits `dst = (size)value`.
//
// As of kernel 4.20, only DWord size is accepted.
func LoadImm(dst Register, value int64, size Size) Instruction {
return Instruction{
OpCode: LoadImmOp(size),
Dst: dst,
Constant: value,
}
}
// LoadMapPtr stores a pointer to a map in dst.
func LoadMapPtr(dst Register, fd int) Instruction {
if fd < 0 {
return Instruction{OpCode: InvalidOpCode}
}
return Instruction{
OpCode: LoadImmOp(DWord),
Dst: dst,
Src: PseudoMapFD,
Constant: int64(uint32(fd)),
}
}
// LoadMapValue stores a pointer to the value at a certain offset of a map.
func LoadMapValue(dst Register, fd int, offset uint32) Instruction {
if fd < 0 {
return Instruction{OpCode: InvalidOpCode}
}
fdAndOffset := (uint64(offset) << 32) | uint64(uint32(fd))
return Instruction{
OpCode: LoadImmOp(DWord),
Dst: dst,
Src: PseudoMapValue,
Constant: int64(fdAndOffset),
}
}
// LoadIndOp returns the OpCode for loading a value of given size from an sk_buff.
func LoadIndOp(size Size) OpCode {
return OpCode(LdClass).SetMode(IndMode).SetSize(size)
}
// LoadInd emits `dst = ntoh(*(size *)(((sk_buff *)R6)->data + src + offset))`.
func LoadInd(dst, src Register, offset int32, size Size) Instruction {
return Instruction{
OpCode: LoadIndOp(size),
Dst: dst,
Src: src,
Constant: int64(offset),
}
}
// LoadAbsOp returns the OpCode for loading a value of given size from an sk_buff.
func LoadAbsOp(size Size) OpCode {
return OpCode(LdClass).SetMode(AbsMode).SetSize(size)
}
// LoadAbs emits `r0 = ntoh(*(size *)(((sk_buff *)R6)->data + offset))`.
func LoadAbs(offset int32, size Size) Instruction {
return Instruction{
OpCode: LoadAbsOp(size),
Dst: R0,
Constant: int64(offset),
}
}
// StoreMemOp returns the OpCode for storing a register of given size in memory.
func StoreMemOp(size Size) OpCode {
return OpCode(StXClass).SetMode(MemMode).SetSize(size)
}
// StoreMem emits `*(size *)(dst + offset) = src`
func StoreMem(dst Register, offset int16, src Register, size Size) Instruction {
return Instruction{
OpCode: StoreMemOp(size),
Dst: dst,
Src: src,
Offset: offset,
}
}
// StoreImmOp returns the OpCode for storing an immediate of given size in memory.
func StoreImmOp(size Size) OpCode {
return OpCode(StClass).SetMode(MemMode).SetSize(size)
}
// StoreImm emits `*(size *)(dst + offset) = value`.
func StoreImm(dst Register, offset int16, value int64, size Size) Instruction {
return Instruction{
OpCode: StoreImmOp(size),
Dst: dst,
Offset: offset,
Constant: value,
}
}
// StoreXAddOp returns the OpCode to atomically add a register to a value in memory.
func StoreXAddOp(size Size) OpCode {
return OpCode(StXClass).SetMode(XAddMode).SetSize(size)
}
// StoreXAdd atomically adds src to *dst.
func StoreXAdd(dst, src Register, size Size) Instruction {
return Instruction{
OpCode: StoreXAddOp(size),
Dst: dst,
Src: src,
}
}