void do_tlb_overlap_fault()

in mm/tlb.c [719:780]

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

void do_tlb_overlap_fault(unsigned long cause, unsigned long address,
			  struct pt_regs *regs)
{
	struct cpuinfo_arc_mmu *mmu = &cpuinfo_arc700[smp_processor_id()].mmu;
	unsigned long flags;
	int set, n_ways = mmu->ways;

	n_ways = min(n_ways, 4);
	BUG_ON(mmu->ways > 4);

	local_irq_save(flags);

	/* loop thru all sets of TLB */
	for (set = 0; set < mmu->sets; set++) {

		int is_valid, way;
		unsigned int pd0[4];

		/* read out all the ways of current set */
		for (way = 0, is_valid = 0; way < n_ways; way++) {
			write_aux_reg(ARC_REG_TLBINDEX,
					  SET_WAY_TO_IDX(mmu, set, way));
			write_aux_reg(ARC_REG_TLBCOMMAND, TLBRead);
			pd0[way] = read_aux_reg(ARC_REG_TLBPD0);
			is_valid |= pd0[way] & _PAGE_PRESENT;
			pd0[way] &= PAGE_MASK;
		}

		/* If all the WAYS in SET are empty, skip to next SET */
		if (!is_valid)
			continue;

		/* Scan the set for duplicate ways: needs a nested loop */
		for (way = 0; way < n_ways - 1; way++) {

			int n;

			if (!pd0[way])
				continue;

			for (n = way + 1; n < n_ways; n++) {
				if (pd0[way] != pd0[n])
					continue;

				if (!dup_pd_silent)
					pr_info("Dup TLB PD0 %08x @ set %d ways %d,%d\n",
						pd0[way], set, way, n);

				/*
				 * clear entry @way and not @n.
				 * This is critical to our optimised loop
				 */
				pd0[way] = 0;
				write_aux_reg(ARC_REG_TLBINDEX,
						SET_WAY_TO_IDX(mmu, set, way));
				__tlb_entry_erase();
			}
		}
	}

	local_irq_restore(flags);
}