int __kprobes parisc_kprobe_ss_handler()

in kernel/kprobes.c [131:176]

• 31 lines of code
• 9 McCabe index (conditional complexity)

int __kprobes parisc_kprobe_ss_handler(struct pt_regs *regs)
{
	struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
	struct kprobe *p = kprobe_running();

	if (!p)
		return 0;

	if (regs->iaoq[0] != (unsigned long)p->ainsn.insn+4)
		return 0;

	/* restore back original saved kprobe variables and continue */
	if (kcb->kprobe_status == KPROBE_REENTER) {
		restore_previous_kprobe(kcb);
		return 1;
	}

	/* for absolute branch instructions we can copy iaoq_b. for relative
	 * branch instructions we need to calculate the new address based on the
	 * difference between iaoq_f and iaoq_b. We cannot use iaoq_b without
	 * modificationt because it's based on our ainsn.insn address.
	 */

	if (p->post_handler)
		p->post_handler(p, regs, 0);

	switch (regs->iir >> 26) {
	case 0x38: /* BE */
	case 0x39: /* BE,L */
	case 0x3a: /* BV */
	case 0x3b: /* BVE */
		/* for absolute branches, regs->iaoq[1] has already the right
		 * address
		 */
		regs->iaoq[0] = kcb->iaoq[1];
		break;
	default:
		regs->iaoq[1] = kcb->iaoq[0];
		regs->iaoq[1] += (regs->iaoq[1] - regs->iaoq[0]) + 4;
		regs->iaoq[0] = kcb->iaoq[1];
		break;
	}
	kcb->kprobe_status = KPROBE_HIT_SSDONE;
	reset_current_kprobe();
	return 1;
}