static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
		  int oldproglen, struct jit_context *ctx, bool jmp_padding)
{
	bool tail_call_reachable = bpf_prog->aux->tail_call_reachable;
	struct bpf_insn *insn = bpf_prog->insnsi;
	bool callee_regs_used[4] = {};
	int insn_cnt = bpf_prog->len;
	bool tail_call_seen = false;
	bool seen_exit = false;
	u8 temp[BPF_MAX_INSN_SIZE + BPF_INSN_SAFETY];
	int i, cnt = 0, excnt = 0;
	int ilen, proglen = 0;
	u8 *prog = temp;
	int err;

	detect_reg_usage(insn, insn_cnt, callee_regs_used,
			 &tail_call_seen);

	/* tail call's presence in current prog implies it is reachable */
	tail_call_reachable |= tail_call_seen;

	emit_prologue(&prog, bpf_prog->aux->stack_depth,
		      bpf_prog_was_classic(bpf_prog), tail_call_reachable,
		      bpf_prog->aux->func_idx != 0);
	push_callee_regs(&prog, callee_regs_used);

	ilen = prog - temp;
	if (image)
		memcpy(image + proglen, temp, ilen);
	proglen += ilen;
	addrs[0] = proglen;
	prog = temp;

	for (i = 1; i <= insn_cnt; i++, insn++) {
		const s32 imm32 = insn->imm;
		u32 dst_reg = insn->dst_reg;
		u32 src_reg = insn->src_reg;
		u8 b2 = 0, b3 = 0;
		u8 *start_of_ldx;
		s64 jmp_offset;
		u8 jmp_cond;
		u8 *func;
		int nops;

		switch (insn->code) {
			/* ALU */
		case BPF_ALU | BPF_ADD | BPF_X:
		case BPF_ALU | BPF_SUB | BPF_X:
		case BPF_ALU | BPF_AND | BPF_X:
		case BPF_ALU | BPF_OR | BPF_X:
		case BPF_ALU | BPF_XOR | BPF_X:
		case BPF_ALU64 | BPF_ADD | BPF_X:
		case BPF_ALU64 | BPF_SUB | BPF_X:
		case BPF_ALU64 | BPF_AND | BPF_X:
		case BPF_ALU64 | BPF_OR | BPF_X:
		case BPF_ALU64 | BPF_XOR | BPF_X:
			maybe_emit_mod(&prog, dst_reg, src_reg,
				       BPF_CLASS(insn->code) == BPF_ALU64);
			b2 = simple_alu_opcodes[BPF_OP(insn->code)];
			EMIT2(b2, add_2reg(0xC0, dst_reg, src_reg));
			break;

		case BPF_ALU64 | BPF_MOV | BPF_X:
		case BPF_ALU | BPF_MOV | BPF_X:
			emit_mov_reg(&prog,
				     BPF_CLASS(insn->code) == BPF_ALU64,
				     dst_reg, src_reg);
			break;

			/* neg dst */
		case BPF_ALU | BPF_NEG:
		case BPF_ALU64 | BPF_NEG:
			if (BPF_CLASS(insn->code) == BPF_ALU64)
				EMIT1(add_1mod(0x48, dst_reg));
			else if (is_ereg(dst_reg))
				EMIT1(add_1mod(0x40, dst_reg));
			EMIT2(0xF7, add_1reg(0xD8, dst_reg));
			break;

		case BPF_ALU | BPF_ADD | BPF_K:
		case BPF_ALU | BPF_SUB | BPF_K:
		case BPF_ALU | BPF_AND | BPF_K:
		case BPF_ALU | BPF_OR | BPF_K:
		case BPF_ALU | BPF_XOR | BPF_K:
		case BPF_ALU64 | BPF_ADD | BPF_K:
		case BPF_ALU64 | BPF_SUB | BPF_K:
		case BPF_ALU64 | BPF_AND | BPF_K:
		case BPF_ALU64 | BPF_OR | BPF_K:
		case BPF_ALU64 | BPF_XOR | BPF_K:
			if (BPF_CLASS(insn->code) == BPF_ALU64)
				EMIT1(add_1mod(0x48, dst_reg));
			else if (is_ereg(dst_reg))
				EMIT1(add_1mod(0x40, dst_reg));

			/*
			 * b3 holds 'normal' opcode, b2 short form only valid
			 * in case dst is eax/rax.
			 */
			switch (BPF_OP(insn->code)) {
			case BPF_ADD:
				b3 = 0xC0;
				b2 = 0x05;
				break;
			case BPF_SUB:
				b3 = 0xE8;
				b2 = 0x2D;
				break;
			case BPF_AND:
				b3 = 0xE0;
				b2 = 0x25;
				break;
			case BPF_OR:
				b3 = 0xC8;
				b2 = 0x0D;
				break;
			case BPF_XOR:
				b3 = 0xF0;
				b2 = 0x35;
				break;
			}

			if (is_imm8(imm32))
				EMIT3(0x83, add_1reg(b3, dst_reg), imm32);
			else if (is_axreg(dst_reg))
				EMIT1_off32(b2, imm32);
			else
				EMIT2_off32(0x81, add_1reg(b3, dst_reg), imm32);
			break;

		case BPF_ALU64 | BPF_MOV | BPF_K:
		case BPF_ALU | BPF_MOV | BPF_K:
			emit_mov_imm32(&prog, BPF_CLASS(insn->code) == BPF_ALU64,
				       dst_reg, imm32);
			break;

		case BPF_LD | BPF_IMM | BPF_DW:
			emit_mov_imm64(&prog, dst_reg, insn[1].imm, insn[0].imm);
			insn++;
			i++;
			break;

			/* dst %= src, dst /= src, dst %= imm32, dst /= imm32 */
		case BPF_ALU | BPF_MOD | BPF_X:
		case BPF_ALU | BPF_DIV | BPF_X:
		case BPF_ALU | BPF_MOD | BPF_K:
		case BPF_ALU | BPF_DIV | BPF_K:
		case BPF_ALU64 | BPF_MOD | BPF_X:
		case BPF_ALU64 | BPF_DIV | BPF_X:
		case BPF_ALU64 | BPF_MOD | BPF_K:
		case BPF_ALU64 | BPF_DIV | BPF_K:
			EMIT1(0x50); /* push rax */
			EMIT1(0x52); /* push rdx */

			if (BPF_SRC(insn->code) == BPF_X)
				/* mov r11, src_reg */
				EMIT_mov(AUX_REG, src_reg);
			else
				/* mov r11, imm32 */
				EMIT3_off32(0x49, 0xC7, 0xC3, imm32);

			/* mov rax, dst_reg */
			EMIT_mov(BPF_REG_0, dst_reg);

			/*
			 * xor edx, edx
			 * equivalent to 'xor rdx, rdx', but one byte less
			 */
			EMIT2(0x31, 0xd2);

			if (BPF_CLASS(insn->code) == BPF_ALU64)
				/* div r11 */
				EMIT3(0x49, 0xF7, 0xF3);
			else
				/* div r11d */
				EMIT3(0x41, 0xF7, 0xF3);

			if (BPF_OP(insn->code) == BPF_MOD)
				/* mov r11, rdx */
				EMIT3(0x49, 0x89, 0xD3);
			else
				/* mov r11, rax */
				EMIT3(0x49, 0x89, 0xC3);

			EMIT1(0x5A); /* pop rdx */
			EMIT1(0x58); /* pop rax */

			/* mov dst_reg, r11 */
			EMIT_mov(dst_reg, AUX_REG);
			break;

		case BPF_ALU | BPF_MUL | BPF_K:
		case BPF_ALU | BPF_MUL | BPF_X:
		case BPF_ALU64 | BPF_MUL | BPF_K:
		case BPF_ALU64 | BPF_MUL | BPF_X:
		{
			bool is64 = BPF_CLASS(insn->code) == BPF_ALU64;

			if (dst_reg != BPF_REG_0)
				EMIT1(0x50); /* push rax */
			if (dst_reg != BPF_REG_3)
				EMIT1(0x52); /* push rdx */

			/* mov r11, dst_reg */
			EMIT_mov(AUX_REG, dst_reg);

			if (BPF_SRC(insn->code) == BPF_X)
				emit_mov_reg(&prog, is64, BPF_REG_0, src_reg);
			else
				emit_mov_imm32(&prog, is64, BPF_REG_0, imm32);

			if (is64)
				EMIT1(add_1mod(0x48, AUX_REG));
			else if (is_ereg(AUX_REG))
				EMIT1(add_1mod(0x40, AUX_REG));
			/* mul(q) r11 */
			EMIT2(0xF7, add_1reg(0xE0, AUX_REG));

			if (dst_reg != BPF_REG_3)
				EMIT1(0x5A); /* pop rdx */
			if (dst_reg != BPF_REG_0) {
				/* mov dst_reg, rax */
				EMIT_mov(dst_reg, BPF_REG_0);
				EMIT1(0x58); /* pop rax */
			}
			break;
		}
			/* Shifts */
		case BPF_ALU | BPF_LSH | BPF_K:
		case BPF_ALU | BPF_RSH | BPF_K:
		case BPF_ALU | BPF_ARSH | BPF_K:
		case BPF_ALU64 | BPF_LSH | BPF_K:
		case BPF_ALU64 | BPF_RSH | BPF_K:
		case BPF_ALU64 | BPF_ARSH | BPF_K:
			if (BPF_CLASS(insn->code) == BPF_ALU64)
				EMIT1(add_1mod(0x48, dst_reg));
			else if (is_ereg(dst_reg))
				EMIT1(add_1mod(0x40, dst_reg));

			b3 = simple_alu_opcodes[BPF_OP(insn->code)];
			if (imm32 == 1)
				EMIT2(0xD1, add_1reg(b3, dst_reg));
			else
				EMIT3(0xC1, add_1reg(b3, dst_reg), imm32);
			break;

		case BPF_ALU | BPF_LSH | BPF_X:
		case BPF_ALU | BPF_RSH | BPF_X:
		case BPF_ALU | BPF_ARSH | BPF_X:
		case BPF_ALU64 | BPF_LSH | BPF_X:
		case BPF_ALU64 | BPF_RSH | BPF_X:
		case BPF_ALU64 | BPF_ARSH | BPF_X:

			/* Check for bad case when dst_reg == rcx */
			if (dst_reg == BPF_REG_4) {
				/* mov r11, dst_reg */
				EMIT_mov(AUX_REG, dst_reg);
				dst_reg = AUX_REG;
			}

			if (src_reg != BPF_REG_4) { /* common case */
				EMIT1(0x51); /* push rcx */

				/* mov rcx, src_reg */
				EMIT_mov(BPF_REG_4, src_reg);
			}

			/* shl %rax, %cl | shr %rax, %cl | sar %rax, %cl */
			if (BPF_CLASS(insn->code) == BPF_ALU64)
				EMIT1(add_1mod(0x48, dst_reg));
			else if (is_ereg(dst_reg))
				EMIT1(add_1mod(0x40, dst_reg));

			b3 = simple_alu_opcodes[BPF_OP(insn->code)];
			EMIT2(0xD3, add_1reg(b3, dst_reg));

			if (src_reg != BPF_REG_4)
				EMIT1(0x59); /* pop rcx */

			if (insn->dst_reg == BPF_REG_4)
				/* mov dst_reg, r11 */
				EMIT_mov(insn->dst_reg, AUX_REG);
			break;

		case BPF_ALU | BPF_END | BPF_FROM_BE:
			switch (imm32) {
			case 16:
				/* Emit 'ror %ax, 8' to swap lower 2 bytes */
				EMIT1(0x66);
				if (is_ereg(dst_reg))
					EMIT1(0x41);
				EMIT3(0xC1, add_1reg(0xC8, dst_reg), 8);

				/* Emit 'movzwl eax, ax' */
				if (is_ereg(dst_reg))
					EMIT3(0x45, 0x0F, 0xB7);
				else
					EMIT2(0x0F, 0xB7);
				EMIT1(add_2reg(0xC0, dst_reg, dst_reg));
				break;
			case 32:
				/* Emit 'bswap eax' to swap lower 4 bytes */
				if (is_ereg(dst_reg))
					EMIT2(0x41, 0x0F);
				else
					EMIT1(0x0F);
				EMIT1(add_1reg(0xC8, dst_reg));
				break;
			case 64:
				/* Emit 'bswap rax' to swap 8 bytes */
				EMIT3(add_1mod(0x48, dst_reg), 0x0F,
				      add_1reg(0xC8, dst_reg));
				break;
			}
			break;

		case BPF_ALU | BPF_END | BPF_FROM_LE:
			switch (imm32) {
			case 16:
				/*
				 * Emit 'movzwl eax, ax' to zero extend 16-bit
				 * into 64 bit
				 */
				if (is_ereg(dst_reg))
					EMIT3(0x45, 0x0F, 0xB7);
				else
					EMIT2(0x0F, 0xB7);
				EMIT1(add_2reg(0xC0, dst_reg, dst_reg));
				break;
			case 32:
				/* Emit 'mov eax, eax' to clear upper 32-bits */
				if (is_ereg(dst_reg))
					EMIT1(0x45);
				EMIT2(0x89, add_2reg(0xC0, dst_reg, dst_reg));
				break;
			case 64:
				/* nop */
				break;
			}
			break;

			/* ST: *(u8*)(dst_reg + off) = imm */
		case BPF_ST | BPF_MEM | BPF_B:
			if (is_ereg(dst_reg))
				EMIT2(0x41, 0xC6);
			else
				EMIT1(0xC6);
			goto st;
		case BPF_ST | BPF_MEM | BPF_H:
			if (is_ereg(dst_reg))
				EMIT3(0x66, 0x41, 0xC7);
			else
				EMIT2(0x66, 0xC7);
			goto st;
		case BPF_ST | BPF_MEM | BPF_W:
			if (is_ereg(dst_reg))
				EMIT2(0x41, 0xC7);
			else
				EMIT1(0xC7);
			goto st;
		case BPF_ST | BPF_MEM | BPF_DW:
			EMIT2(add_1mod(0x48, dst_reg), 0xC7);

st:			if (is_imm8(insn->off))
				EMIT2(add_1reg(0x40, dst_reg), insn->off);
			else
				EMIT1_off32(add_1reg(0x80, dst_reg), insn->off);

			EMIT(imm32, bpf_size_to_x86_bytes(BPF_SIZE(insn->code)));
			break;

			/* STX: *(u8*)(dst_reg + off) = src_reg */
		case BPF_STX | BPF_MEM | BPF_B:
		case BPF_STX | BPF_MEM | BPF_H:
		case BPF_STX | BPF_MEM | BPF_W:
		case BPF_STX | BPF_MEM | BPF_DW:
			emit_stx(&prog, BPF_SIZE(insn->code), dst_reg, src_reg, insn->off);
			break;

			/* LDX: dst_reg = *(u8*)(src_reg + off) */
		case BPF_LDX | BPF_MEM | BPF_B:
		case BPF_LDX | BPF_PROBE_MEM | BPF_B:
		case BPF_LDX | BPF_MEM | BPF_H:
		case BPF_LDX | BPF_PROBE_MEM | BPF_H:
		case BPF_LDX | BPF_MEM | BPF_W:
		case BPF_LDX | BPF_PROBE_MEM | BPF_W:
		case BPF_LDX | BPF_MEM | BPF_DW:
		case BPF_LDX | BPF_PROBE_MEM | BPF_DW:
			if (BPF_MODE(insn->code) == BPF_PROBE_MEM) {
				/* test src_reg, src_reg */
				maybe_emit_mod(&prog, src_reg, src_reg, true); /* always 1 byte */
				EMIT2(0x85, add_2reg(0xC0, src_reg, src_reg));
				/* jne start_of_ldx */
				EMIT2(X86_JNE, 0);
				/* xor dst_reg, dst_reg */
				emit_mov_imm32(&prog, false, dst_reg, 0);
				/* jmp byte_after_ldx */
				EMIT2(0xEB, 0);

				/* populate jmp_offset for JNE above */
				temp[4] = prog - temp - 5 /* sizeof(test + jne) */;
				start_of_ldx = prog;
			}
			emit_ldx(&prog, BPF_SIZE(insn->code), dst_reg, src_reg, insn->off);
			if (BPF_MODE(insn->code) == BPF_PROBE_MEM) {
				struct exception_table_entry *ex;
				u8 *_insn = image + proglen;
				s64 delta;

				/* populate jmp_offset for JMP above */
				start_of_ldx[-1] = prog - start_of_ldx;

				if (!bpf_prog->aux->extable)
					break;

				if (excnt >= bpf_prog->aux->num_exentries) {
					pr_err("ex gen bug\n");
					return -EFAULT;
				}
				ex = &bpf_prog->aux->extable[excnt++];

				delta = _insn - (u8 *)&ex->insn;
				if (!is_simm32(delta)) {
					pr_err("extable->insn doesn't fit into 32-bit\n");
					return -EFAULT;
				}
				ex->insn = delta;

				delta = (u8 *)ex_handler_bpf - (u8 *)&ex->handler;
				if (!is_simm32(delta)) {
					pr_err("extable->handler doesn't fit into 32-bit\n");
					return -EFAULT;
				}
				ex->handler = delta;

				if (dst_reg > BPF_REG_9) {
					pr_err("verifier error\n");
					return -EFAULT;
				}
				/*
				 * Compute size of x86 insn and its target dest x86 register.
				 * ex_handler_bpf() will use lower 8 bits to adjust
				 * pt_regs->ip to jump over this x86 instruction
				 * and upper bits to figure out which pt_regs to zero out.
				 * End result: x86 insn "mov rbx, qword ptr [rax+0x14]"
				 * of 4 bytes will be ignored and rbx will be zero inited.
				 */
				ex->fixup = (prog - temp) | (reg2pt_regs[dst_reg] << 8);
			}
			break;

		case BPF_STX | BPF_ATOMIC | BPF_W:
		case BPF_STX | BPF_ATOMIC | BPF_DW:
			if (insn->imm == (BPF_AND | BPF_FETCH) ||
			    insn->imm == (BPF_OR | BPF_FETCH) ||
			    insn->imm == (BPF_XOR | BPF_FETCH)) {
				u8 *branch_target;
				bool is64 = BPF_SIZE(insn->code) == BPF_DW;
				u32 real_src_reg = src_reg;

				/*
				 * Can't be implemented with a single x86 insn.
				 * Need to do a CMPXCHG loop.
				 */

				/* Will need RAX as a CMPXCHG operand so save R0 */
				emit_mov_reg(&prog, true, BPF_REG_AX, BPF_REG_0);
				if (src_reg == BPF_REG_0)
					real_src_reg = BPF_REG_AX;

				branch_target = prog;
				/* Load old value */
				emit_ldx(&prog, BPF_SIZE(insn->code),
					 BPF_REG_0, dst_reg, insn->off);
				/*
				 * Perform the (commutative) operation locally,
				 * put the result in the AUX_REG.
				 */
				emit_mov_reg(&prog, is64, AUX_REG, BPF_REG_0);
				maybe_emit_mod(&prog, AUX_REG, real_src_reg, is64);
				EMIT2(simple_alu_opcodes[BPF_OP(insn->imm)],
				      add_2reg(0xC0, AUX_REG, real_src_reg));
				/* Attempt to swap in new value */
				err = emit_atomic(&prog, BPF_CMPXCHG,
						  dst_reg, AUX_REG, insn->off,
						  BPF_SIZE(insn->code));
				if (WARN_ON(err))
					return err;
				/*
				 * ZF tells us whether we won the race. If it's
				 * cleared we need to try again.
				 */
				EMIT2(X86_JNE, -(prog - branch_target) - 2);
				/* Return the pre-modification value */
				emit_mov_reg(&prog, is64, real_src_reg, BPF_REG_0);
				/* Restore R0 after clobbering RAX */
				emit_mov_reg(&prog, true, BPF_REG_0, BPF_REG_AX);
				break;

			}

			err = emit_atomic(&prog, insn->imm, dst_reg, src_reg,
						  insn->off, BPF_SIZE(insn->code));
			if (err)
				return err;
			break;

			/* call */
		case BPF_JMP | BPF_CALL:
			func = (u8 *) __bpf_call_base + imm32;
			if (tail_call_reachable) {
				EMIT3_off32(0x48, 0x8B, 0x85,
					    -(bpf_prog->aux->stack_depth + 8));
				if (!imm32 || emit_call(&prog, func, image + addrs[i - 1] + 7))
					return -EINVAL;
			} else {
				if (!imm32 || emit_call(&prog, func, image + addrs[i - 1]))
					return -EINVAL;
			}
			break;

		case BPF_JMP | BPF_TAIL_CALL:
			if (imm32)
				emit_bpf_tail_call_direct(&bpf_prog->aux->poke_tab[imm32 - 1],
							  &prog, addrs[i], image,
							  callee_regs_used,
							  bpf_prog->aux->stack_depth);
			else
				emit_bpf_tail_call_indirect(&prog,
							    callee_regs_used,
							    bpf_prog->aux->stack_depth);
			break;

			/* cond jump */
		case BPF_JMP | BPF_JEQ | BPF_X:
		case BPF_JMP | BPF_JNE | BPF_X:
		case BPF_JMP | BPF_JGT | BPF_X:
		case BPF_JMP | BPF_JLT | BPF_X:
		case BPF_JMP | BPF_JGE | BPF_X:
		case BPF_JMP | BPF_JLE | BPF_X:
		case BPF_JMP | BPF_JSGT | BPF_X:
		case BPF_JMP | BPF_JSLT | BPF_X:
		case BPF_JMP | BPF_JSGE | BPF_X:
		case BPF_JMP | BPF_JSLE | BPF_X:
		case BPF_JMP32 | BPF_JEQ | BPF_X:
		case BPF_JMP32 | BPF_JNE | BPF_X:
		case BPF_JMP32 | BPF_JGT | BPF_X:
		case BPF_JMP32 | BPF_JLT | BPF_X:
		case BPF_JMP32 | BPF_JGE | BPF_X:
		case BPF_JMP32 | BPF_JLE | BPF_X:
		case BPF_JMP32 | BPF_JSGT | BPF_X:
		case BPF_JMP32 | BPF_JSLT | BPF_X:
		case BPF_JMP32 | BPF_JSGE | BPF_X:
		case BPF_JMP32 | BPF_JSLE | BPF_X:
			/* cmp dst_reg, src_reg */
			maybe_emit_mod(&prog, dst_reg, src_reg,
				       BPF_CLASS(insn->code) == BPF_JMP);
			EMIT2(0x39, add_2reg(0xC0, dst_reg, src_reg));
			goto emit_cond_jmp;

		case BPF_JMP | BPF_JSET | BPF_X:
		case BPF_JMP32 | BPF_JSET | BPF_X:
			/* test dst_reg, src_reg */
			maybe_emit_mod(&prog, dst_reg, src_reg,
				       BPF_CLASS(insn->code) == BPF_JMP);
			EMIT2(0x85, add_2reg(0xC0, dst_reg, src_reg));
			goto emit_cond_jmp;

		case BPF_JMP | BPF_JSET | BPF_K:
		case BPF_JMP32 | BPF_JSET | BPF_K:
			/* test dst_reg, imm32 */
			if (BPF_CLASS(insn->code) == BPF_JMP)
				EMIT1(add_1mod(0x48, dst_reg));
			else if (is_ereg(dst_reg))
				EMIT1(add_1mod(0x40, dst_reg));
			EMIT2_off32(0xF7, add_1reg(0xC0, dst_reg), imm32);
			goto emit_cond_jmp;

		case BPF_JMP | BPF_JEQ | BPF_K:
		case BPF_JMP | BPF_JNE | BPF_K:
		case BPF_JMP | BPF_JGT | BPF_K:
		case BPF_JMP | BPF_JLT | BPF_K:
		case BPF_JMP | BPF_JGE | BPF_K:
		case BPF_JMP | BPF_JLE | BPF_K:
		case BPF_JMP | BPF_JSGT | BPF_K:
		case BPF_JMP | BPF_JSLT | BPF_K:
		case BPF_JMP | BPF_JSGE | BPF_K:
		case BPF_JMP | BPF_JSLE | BPF_K:
		case BPF_JMP32 | BPF_JEQ | BPF_K:
		case BPF_JMP32 | BPF_JNE | BPF_K:
		case BPF_JMP32 | BPF_JGT | BPF_K:
		case BPF_JMP32 | BPF_JLT | BPF_K:
		case BPF_JMP32 | BPF_JGE | BPF_K:
		case BPF_JMP32 | BPF_JLE | BPF_K:
		case BPF_JMP32 | BPF_JSGT | BPF_K:
		case BPF_JMP32 | BPF_JSLT | BPF_K:
		case BPF_JMP32 | BPF_JSGE | BPF_K:
		case BPF_JMP32 | BPF_JSLE | BPF_K:
			/* test dst_reg, dst_reg to save one extra byte */
			if (imm32 == 0) {
				maybe_emit_mod(&prog, dst_reg, dst_reg,
					       BPF_CLASS(insn->code) == BPF_JMP);
				EMIT2(0x85, add_2reg(0xC0, dst_reg, dst_reg));
				goto emit_cond_jmp;
			}

			/* cmp dst_reg, imm8/32 */
			if (BPF_CLASS(insn->code) == BPF_JMP)
				EMIT1(add_1mod(0x48, dst_reg));
			else if (is_ereg(dst_reg))
				EMIT1(add_1mod(0x40, dst_reg));

			if (is_imm8(imm32))
				EMIT3(0x83, add_1reg(0xF8, dst_reg), imm32);
			else
				EMIT2_off32(0x81, add_1reg(0xF8, dst_reg), imm32);

emit_cond_jmp:		/* Convert BPF opcode to x86 */
			switch (BPF_OP(insn->code)) {
			case BPF_JEQ:
				jmp_cond = X86_JE;
				break;
			case BPF_JSET:
			case BPF_JNE:
				jmp_cond = X86_JNE;
				break;
			case BPF_JGT:
				/* GT is unsigned '>', JA in x86 */
				jmp_cond = X86_JA;
				break;
			case BPF_JLT:
				/* LT is unsigned '<', JB in x86 */
				jmp_cond = X86_JB;
				break;
			case BPF_JGE:
				/* GE is unsigned '>=', JAE in x86 */
				jmp_cond = X86_JAE;
				break;
			case BPF_JLE:
				/* LE is unsigned '<=', JBE in x86 */
				jmp_cond = X86_JBE;
				break;
			case BPF_JSGT:
				/* Signed '>', GT in x86 */
				jmp_cond = X86_JG;
				break;
			case BPF_JSLT:
				/* Signed '<', LT in x86 */
				jmp_cond = X86_JL;
				break;
			case BPF_JSGE:
				/* Signed '>=', GE in x86 */
				jmp_cond = X86_JGE;
				break;
			case BPF_JSLE:
				/* Signed '<=', LE in x86 */
				jmp_cond = X86_JLE;
				break;
			default: /* to silence GCC warning */
				return -EFAULT;
			}
			jmp_offset = addrs[i + insn->off] - addrs[i];
			if (is_imm8(jmp_offset)) {
				if (jmp_padding) {
					/* To keep the jmp_offset valid, the extra bytes are
					 * padded before the jump insn, so we substract the
					 * 2 bytes of jmp_cond insn from INSN_SZ_DIFF.
					 *
					 * If the previous pass already emits an imm8
					 * jmp_cond, then this BPF insn won't shrink, so
					 * "nops" is 0.
					 *
					 * On the other hand, if the previous pass emits an
					 * imm32 jmp_cond, the extra 4 bytes(*) is padded to
					 * keep the image from shrinking further.
					 *
					 * (*) imm32 jmp_cond is 6 bytes, and imm8 jmp_cond
					 *     is 2 bytes, so the size difference is 4 bytes.
					 */
					nops = INSN_SZ_DIFF - 2;
					if (nops != 0 && nops != 4) {
						pr_err("unexpected jmp_cond padding: %d bytes\n",
						       nops);
						return -EFAULT;
					}
					cnt += emit_nops(&prog, nops);
				}
				EMIT2(jmp_cond, jmp_offset);
			} else if (is_simm32(jmp_offset)) {
				EMIT2_off32(0x0F, jmp_cond + 0x10, jmp_offset);
			} else {
				pr_err("cond_jmp gen bug %llx\n", jmp_offset);
				return -EFAULT;
			}

			break;

		case BPF_JMP | BPF_JA:
			if (insn->off == -1)
				/* -1 jmp instructions will always jump
				 * backwards two bytes. Explicitly handling
				 * this case avoids wasting too many passes
				 * when there are long sequences of replaced
				 * dead code.
				 */
				jmp_offset = -2;
			else
				jmp_offset = addrs[i + insn->off] - addrs[i];

			if (!jmp_offset) {
				/*
				 * If jmp_padding is enabled, the extra nops will
				 * be inserted. Otherwise, optimize out nop jumps.
				 */
				if (jmp_padding) {
					/* There are 3 possible conditions.
					 * (1) This BPF_JA is already optimized out in
					 *     the previous run, so there is no need
					 *     to pad any extra byte (0 byte).
					 * (2) The previous pass emits an imm8 jmp,
					 *     so we pad 2 bytes to match the previous
					 *     insn size.
					 * (3) Similarly, the previous pass emits an
					 *     imm32 jmp, and 5 bytes is padded.
					 */
					nops = INSN_SZ_DIFF;
					if (nops != 0 && nops != 2 && nops != 5) {
						pr_err("unexpected nop jump padding: %d bytes\n",
						       nops);
						return -EFAULT;
					}
					cnt += emit_nops(&prog, nops);
				}
				break;
			}
emit_jmp:
			if (is_imm8(jmp_offset)) {
				if (jmp_padding) {
					/* To avoid breaking jmp_offset, the extra bytes
					 * are padded before the actual jmp insn, so
					 * 2 bytes is substracted from INSN_SZ_DIFF.
					 *
					 * If the previous pass already emits an imm8
					 * jmp, there is nothing to pad (0 byte).
					 *
					 * If it emits an imm32 jmp (5 bytes) previously
					 * and now an imm8 jmp (2 bytes), then we pad
					 * (5 - 2 = 3) bytes to stop the image from
					 * shrinking further.
					 */
					nops = INSN_SZ_DIFF - 2;
					if (nops != 0 && nops != 3) {
						pr_err("unexpected jump padding: %d bytes\n",
						       nops);
						return -EFAULT;
					}
					cnt += emit_nops(&prog, INSN_SZ_DIFF - 2);
				}
				EMIT2(0xEB, jmp_offset);
			} else if (is_simm32(jmp_offset)) {
				EMIT1_off32(0xE9, jmp_offset);
			} else {
				pr_err("jmp gen bug %llx\n", jmp_offset);
				return -EFAULT;
			}
			break;

		case BPF_JMP | BPF_EXIT:
			if (seen_exit) {
				jmp_offset = ctx->cleanup_addr - addrs[i];
				goto emit_jmp;
			}
			seen_exit = true;
			/* Update cleanup_addr */
			ctx->cleanup_addr = proglen;
			pop_callee_regs(&prog, callee_regs_used);
			EMIT1(0xC9);         /* leave */
			EMIT1(0xC3);         /* ret */
			break;

		default:
			/*
			 * By design x86-64 JIT should support all BPF instructions.
			 * This error will be seen if new instruction was added
			 * to the interpreter, but not to the JIT, or if there is
			 * junk in bpf_prog.
			 */
			pr_err("bpf_jit: unknown opcode %02x\n", insn->code);
			return -EINVAL;
		}

		ilen = prog - temp;
		if (ilen > BPF_MAX_INSN_SIZE) {
			pr_err("bpf_jit: fatal insn size error\n");
			return -EFAULT;
		}

		if (image) {
			/*
			 * When populating the image, assert that:
			 *
			 *  i) We do not write beyond the allocated space, and
			 * ii) addrs[i] did not change from the prior run, in order
			 *     to validate assumptions made for computing branch
			 *     displacements.
			 */
			if (unlikely(proglen + ilen > oldproglen ||
				     proglen + ilen != addrs[i])) {
				pr_err("bpf_jit: fatal error\n");
				return -EFAULT;
			}
			memcpy(image + proglen, temp, ilen);
		}
		proglen += ilen;
		addrs[i] = proglen;
		prog = temp;
	}

	if (image && excnt != bpf_prog->aux->num_exentries) {
		pr_err("extable is not populated\n");
		return -EFAULT;
	}
	return proglen;
}