static void __kprobes update_kprobe_inst_flag()

in kernel/kprobes.c [85:130]

• 38 lines of code
• 10 McCabe index (conditional complexity)

static void __kprobes update_kprobe_inst_flag(uint template, uint  slot,
					      uint major_opcode,
					      unsigned long kprobe_inst,
					      struct kprobe *p)
{
	p->ainsn.inst_flag = 0;
	p->ainsn.target_br_reg = 0;
	p->ainsn.slot = slot;

	/* Check for Break instruction
	 * Bits 37:40 Major opcode to be zero
	 * Bits 27:32 X6 to be zero
	 * Bits 32:35 X3 to be zero
	 */
	if ((!major_opcode) && (!((kprobe_inst >> 27) & 0x1FF)) ) {
		/* is a break instruction */
	 	p->ainsn.inst_flag |= INST_FLAG_BREAK_INST;
		return;
	}

	if (bundle_encoding[template][slot] == B) {
		switch (major_opcode) {
		  case INDIRECT_CALL_OPCODE:
	 		p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
			p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
			break;
		  case IP_RELATIVE_PREDICT_OPCODE:
		  case IP_RELATIVE_BRANCH_OPCODE:
			p->ainsn.inst_flag |= INST_FLAG_FIX_RELATIVE_IP_ADDR;
			break;
		  case IP_RELATIVE_CALL_OPCODE:
			p->ainsn.inst_flag |= INST_FLAG_FIX_RELATIVE_IP_ADDR;
			p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
			p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
			break;
		}
	} else if (bundle_encoding[template][slot] == X) {
		switch (major_opcode) {
		  case LONG_CALL_OPCODE:
			p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
			p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
		  break;
		}
	}
	return;
}