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Commit 483e9bcb authored by Vineet Gupta's avatar Vineet Gupta
Browse files

ARC: MMUv4 preps/3 - Abstract out TLB Insert/Delete 



This reorganizes the current TLB operations into psuedo-ops to better
pair with MMUv4's native Insert/Delete operations

Signed-off-by: default avatarVineet Gupta <vgupta@synopsys.com>
parent d091fcb9

arch/arc/include/asm/mmu.h

+2 −0
Original line number Diff line number Diff line
@@ -32,6 +32,8 @@ 
/* Error code if probe fails */

#define TLB_LKUP_ERR		0x80000000



#define TLB_DUP_ERR	(TLB_LKUP_ERR | 0x00000001)



/* TLB Commands */

#define TLBWrite    0x1

#define TLBRead     0x2

arch/arc/mm/tlb.c

+54 −40
Original line number Diff line number Diff line
@@ -52,6 +52,7 @@ 
 */



#include <linux/module.h>

#include <linux/bug.h>

#include <asm/arcregs.h>

#include <asm/setup.h>

#include <asm/mmu_context.h>
@@ -109,39 +110,42 @@ struct mm_struct *asid_mm_map[NUM_ASID + 1]; 


/*

 * Utility Routine to erase a J-TLB entry

 * The procedure is to look it up in the MMU. If found, ERASE it by

 *  issuing a TlbWrite CMD with PD0 = PD1 = 0

 * Caller needs to setup Index Reg (manually or via getIndex)

 */



static void __tlb_entry_erase(void)

static inline void __tlb_entry_erase(void)

{

	write_aux_reg(ARC_REG_TLBPD1, 0);

	write_aux_reg(ARC_REG_TLBPD0, 0);

	write_aux_reg(ARC_REG_TLBCOMMAND, TLBWrite);

}



static void tlb_entry_erase(unsigned int vaddr_n_asid)

static inline unsigned int tlb_entry_lkup(unsigned long vaddr_n_asid)

{

	unsigned int idx;



	/* Locate the TLB entry for this vaddr + ASID */

	write_aux_reg(ARC_REG_TLBPD0, vaddr_n_asid);



	write_aux_reg(ARC_REG_TLBCOMMAND, TLBProbe);

	idx = read_aux_reg(ARC_REG_TLBINDEX);



	return idx;

}



static void tlb_entry_erase(unsigned int vaddr_n_asid)

{

	unsigned int idx;



	/* Locate the TLB entry for this vaddr + ASID */

	idx = tlb_entry_lkup(vaddr_n_asid);



	/* No error means entry found, zero it out */

	if (likely(!(idx & TLB_LKUP_ERR))) {

		__tlb_entry_erase();

	} else {		/* Some sort of Error */



	} else {

		/* Duplicate entry error */

		if (idx & 0x1) {

			/* TODO we need to handle this case too */

			pr_emerg("unhandled Duplicate flush for %x\n",

		WARN(idx == TLB_DUP_ERR, "Probe returned Dup PD for %x\n",

					   vaddr_n_asid);

	}

		/* else entry not found so nothing to do */

	}

}



/****************************************************************************
@@ -159,7 +163,7 @@ static void utlb_invalidate(void) 
{

#if (CONFIG_ARC_MMU_VER >= 2)



#if (CONFIG_ARC_MMU_VER < 3)

#if (CONFIG_ARC_MMU_VER == 2)

	/* MMU v2 introduced the uTLB Flush command.

	 * There was however an obscure hardware bug, where uTLB flush would

	 * fail when a prior probe for J-TLB (both totally unrelated) would
@@ -182,6 +186,36 @@ static void utlb_invalidate(void) 


}



static void tlb_entry_insert(unsigned int pd0, unsigned int pd1)

{

	unsigned int idx;



	/*

	 * First verify if entry for this vaddr+ASID already exists

	 * This also sets up PD0 (vaddr, ASID..) for final commit

	 */

	idx = tlb_entry_lkup(pd0);



	/*

	 * If Not already present get a free slot from MMU.

	 * Otherwise, Probe would have located the entry and set INDEX Reg

	 * with existing location. This will cause Write CMD to over-write

	 * existing entry with new PD0 and PD1

	 */

	if (likely(idx & TLB_LKUP_ERR))

		write_aux_reg(ARC_REG_TLBCOMMAND, TLBGetIndex);



	/* setup the other half of TLB entry (pfn, rwx..) */

	write_aux_reg(ARC_REG_TLBPD1, pd1);



	/*

	 * Commit the Entry to MMU

	 * It doesnt sound safe to use the TLBWriteNI cmd here

	 * which doesn't flush uTLBs. I'd rather be safe than sorry.

	 */

	write_aux_reg(ARC_REG_TLBCOMMAND, TLBWrite);

}



/*

 * Un-conditionally (without lookup) erase the entire MMU contents

 */
@@ -341,7 +375,8 @@ void local_flush_tlb_page(struct vm_area_struct *vma, unsigned long page) 
void create_tlb(struct vm_area_struct *vma, unsigned long address, pte_t *ptep)

{

	unsigned long flags;

	unsigned int idx, asid_or_sasid, rwx;

	unsigned int asid_or_sasid, rwx;

	unsigned long pd0, pd1;



	/*

	 * create_tlb() assumes that current->mm == vma->mm, since
@@ -385,8 +420,7 @@ void create_tlb(struct vm_area_struct *vma, unsigned long address, pte_t *ptep) 
	/* ASID for this task */

	asid_or_sasid = read_aux_reg(ARC_REG_PID) & 0xff;



	write_aux_reg(ARC_REG_TLBPD0, address | asid_or_sasid |

				      (pte_val(*ptep) & PTE_BITS_IN_PD0));

	pd0 = address | asid_or_sasid | (pte_val(*ptep) & PTE_BITS_IN_PD0);



	/*

	 * ARC MMU provides fully orthogonal access bits for K/U mode,
@@ -402,29 +436,9 @@ void create_tlb(struct vm_area_struct *vma, unsigned long address, pte_t *ptep) 
	else

		rwx |= (rwx << 3);	/* r w x => Kr Kw Kx Ur Uw Ux */



	/* Load remaining info in PD1 (Page Frame Addr and Kx/Kw/Kr Flags) */

	write_aux_reg(ARC_REG_TLBPD1,

		      rwx | (pte_val(*ptep) & PTE_BITS_NON_RWX_IN_PD1));



	/* First verify if entry for this vaddr+ASID already exists */

	write_aux_reg(ARC_REG_TLBCOMMAND, TLBProbe);

	idx = read_aux_reg(ARC_REG_TLBINDEX);



	/*

	 * If Not already present get a free slot from MMU.

	 * Otherwise, Probe would have located the entry and set INDEX Reg

	 * with existing location. This will cause Write CMD to over-write

	 * existing entry with new PD0 and PD1

	 */

	if (likely(idx & TLB_LKUP_ERR))

		write_aux_reg(ARC_REG_TLBCOMMAND, TLBGetIndex);

	pd1 = rwx | (pte_val(*ptep) & PTE_BITS_NON_RWX_IN_PD1);



	/*

	 * Commit the Entry to MMU

	 * It doesnt sound safe to use the TLBWriteNI cmd here

	 * which doesn't flush uTLBs. I'd rather be safe than sorry.

	 */

	write_aux_reg(ARC_REG_TLBCOMMAND, TLBWrite);

	tlb_entry_insert(pd0, pd1);



	local_irq_restore(flags);

}