diff options
Diffstat (limited to 'vendor/github.com/cilium/ebpf/asm/jump.go')
-rw-r--r-- | vendor/github.com/cilium/ebpf/asm/jump.go | 109 |
1 files changed, 109 insertions, 0 deletions
diff --git a/vendor/github.com/cilium/ebpf/asm/jump.go b/vendor/github.com/cilium/ebpf/asm/jump.go new file mode 100644 index 000000000..7757179de --- /dev/null +++ b/vendor/github.com/cilium/ebpf/asm/jump.go @@ -0,0 +1,109 @@ +package asm + +//go:generate stringer -output jump_string.go -type=JumpOp + +// JumpOp affect control flow. +// +// msb lsb +// +----+-+---+ +// |OP |s|cls| +// +----+-+---+ +type JumpOp uint8 + +const jumpMask OpCode = aluMask + +const ( + // InvalidJumpOp is returned by getters when invoked + // on non branch OpCodes + InvalidJumpOp JumpOp = 0xff + // Ja jumps by offset unconditionally + Ja JumpOp = 0x00 + // JEq jumps by offset if r == imm + JEq JumpOp = 0x10 + // JGT jumps by offset if r > imm + JGT JumpOp = 0x20 + // JGE jumps by offset if r >= imm + JGE JumpOp = 0x30 + // JSet jumps by offset if r & imm + JSet JumpOp = 0x40 + // JNE jumps by offset if r != imm + JNE JumpOp = 0x50 + // JSGT jumps by offset if signed r > signed imm + JSGT JumpOp = 0x60 + // JSGE jumps by offset if signed r >= signed imm + JSGE JumpOp = 0x70 + // Call builtin or user defined function from imm + Call JumpOp = 0x80 + // Exit ends execution, with value in r0 + Exit JumpOp = 0x90 + // JLT jumps by offset if r < imm + JLT JumpOp = 0xa0 + // JLE jumps by offset if r <= imm + JLE JumpOp = 0xb0 + // JSLT jumps by offset if signed r < signed imm + JSLT JumpOp = 0xc0 + // JSLE jumps by offset if signed r <= signed imm + JSLE JumpOp = 0xd0 +) + +// Return emits an exit instruction. +// +// Requires a return value in R0. +func Return() Instruction { + return Instruction{ + OpCode: OpCode(JumpClass).SetJumpOp(Exit), + } +} + +// Op returns the OpCode for a given jump source. +func (op JumpOp) Op(source Source) OpCode { + return OpCode(JumpClass).SetJumpOp(op).SetSource(source) +} + +// Imm compares dst to value, and adjusts PC by offset if the condition is fulfilled. +func (op JumpOp) Imm(dst Register, value int32, label string) Instruction { + if op == Exit || op == Call || op == Ja { + return Instruction{OpCode: InvalidOpCode} + } + + return Instruction{ + OpCode: OpCode(JumpClass).SetJumpOp(op).SetSource(ImmSource), + Dst: dst, + Offset: -1, + Constant: int64(value), + Reference: label, + } +} + +// Reg compares dst to src, and adjusts PC by offset if the condition is fulfilled. +func (op JumpOp) Reg(dst, src Register, label string) Instruction { + if op == Exit || op == Call || op == Ja { + return Instruction{OpCode: InvalidOpCode} + } + + return Instruction{ + OpCode: OpCode(JumpClass).SetJumpOp(op).SetSource(RegSource), + Dst: dst, + Src: src, + Offset: -1, + Reference: label, + } +} + +// Label adjusts PC to the address of the label. +func (op JumpOp) Label(label string) Instruction { + if op == Call { + return Instruction{ + OpCode: OpCode(JumpClass).SetJumpOp(Call), + Src: PseudoCall, + Constant: -1, + Reference: label, + } + } + + return Instruction{ + OpCode: OpCode(JumpClass).SetJumpOp(op), + Offset: -1, + Reference: label, + } +} |