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Commit 8840e14c authored by Vineet Gupta's avatar Vineet Gupta
Browse files

ARC: mm: Improve Duplicate PD Fault handler 



 - Move the verbosity knob from .data to .bss by using inverted logic
 - No need to readout PD1 descriptor
 - clip the non pfn bits of PD0 to avoid clipping inside the loop

Signed-off-by: default avatarVineet Gupta <vgupta@synopsys.com>
parent 9acdc911

arch/arc/mm/tlb.c

+24 −24
Original line number Diff line number Diff line
@@ -856,15 +856,15 @@ void arc_mmu_init(void) 
 *      the duplicate one.

 * -Knob to be verbose abt it.(TODO: hook them up to debugfs)

 */

volatile int dup_pd_verbose = 1;/* Be slient abt it or complain (default) */

volatile int dup_pd_silent; /* Be slient abt it or complain (default) */



void do_tlb_overlap_fault(unsigned long cause, unsigned long address,

			  struct pt_regs *regs)

{

	int set, way, n;

	unsigned long flags, is_valid;

	struct cpuinfo_arc_mmu *mmu = &cpuinfo_arc700[smp_processor_id()].mmu;

	unsigned int pd0[mmu->ways], pd1[mmu->ways];

	unsigned int pd0[mmu->ways];

	unsigned long flags;

	int set;



	local_irq_save(flags);
@@ -874,14 +874,16 @@ void do_tlb_overlap_fault(unsigned long cause, unsigned long address, 
	/* loop thru all sets of TLB */

	for (set = 0; set < mmu->sets; set++) {



		int is_valid, way;



		/* read out all the ways of current set */

		for (way = 0, is_valid = 0; way < mmu->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);

			pd1[way] = read_aux_reg(ARC_REG_TLBPD1);

			is_valid |= pd0[way] & _PAGE_PRESENT;

			pd0[way] &= PAGE_MASK;

		}



		/* If all the WAYS in SET are empty, skip to next SET */
@@ -890,33 +892,31 @@ void do_tlb_overlap_fault(unsigned long cause, unsigned long address, 


		/* Scan the set for duplicate ways: needs a nested loop */

		for (way = 0; way < mmu->ways - 1; way++) {



			int n;



			if (!pd0[way])

				continue;



			for (n = way + 1; n < mmu->ways; n++) {

				if ((pd0[way] & PAGE_MASK) ==

				    (pd0[n] & PAGE_MASK)) {

				if (pd0[way] != pd0[n])

					continue;



					if (dup_pd_verbose) {

						pr_info("Duplicate PD's @"

							"[%d:%d]/[%d:%d]\n",

						     set, way, set, n);

						pr_info("TLBPD0[%u]: %08x\n",

						     way, pd0[way]);

					}

				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

				 * clear entry @way and not @n.

				 * This is critical to our optimised loop

				 */

					pd0[way] = pd1[way] = 0;

				pd0[way] = 0;

				write_aux_reg(ARC_REG_TLBINDEX,

						SET_WAY_TO_IDX(mmu, set, way));

				__tlb_entry_erase();

			}

		}

	}

	}



	local_irq_restore(flags);

}