tlb_low_64e.S

/*
 *  Low level TLB miss handlers for Book3E
 *
 *  Copyright (C) 2008-2009
 *      Ben. Herrenschmidt (benh@kernel.crashing.org), IBM Corp.
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License
 *  as published by the Free Software Foundation; either version
 *  2 of the License, or (at your option) any later version.
 */

#include <asm/processor.h>
#include <asm/reg.h>
#include <asm/page.h>
#include <asm/mmu.h>
#include <asm/ppc_asm.h>
#include <asm/asm-offsets.h>
#include <asm/cputable.h>
#include <asm/pgtable.h>
#include <asm/exception-64e.h>
#include <asm/ppc-opcode.h>
#include <asm/kvm_asm.h>
#include <asm/kvm_booke_hv_asm.h>

#ifdef CONFIG_PPC_64K_PAGES
#define VPTE_PMD_SHIFT	(PTE_INDEX_SIZE+1)
#else
#define VPTE_PMD_SHIFT	(PTE_INDEX_SIZE)
#endif
#define VPTE_PUD_SHIFT	(VPTE_PMD_SHIFT + PMD_INDEX_SIZE)
#define VPTE_PGD_SHIFT	(VPTE_PUD_SHIFT + PUD_INDEX_SIZE)
#define VPTE_INDEX_SIZE (VPTE_PGD_SHIFT + PGD_INDEX_SIZE)

/**********************************************************************
 *                                                                    *
 * TLB miss handling for Book3E with a bolted linear mapping          *
 * No virtual page table, no nested TLB misses                        *
 *                                                                    *
 **********************************************************************/

.macro tlb_prolog_bolted intnum addr
	mtspr	SPRN_SPRG_GEN_SCRATCH,r13
	mfspr	r13,SPRN_SPRG_PACA
	std	r10,PACA_EXTLB+EX_TLB_R10(r13)
	mfcr	r10
	std	r11,PACA_EXTLB+EX_TLB_R11(r13)
#ifdef CONFIG_KVM_BOOKE_HV
BEGIN_FTR_SECTION
	mfspr	r11, SPRN_SRR1
END_FTR_SECTION_IFSET(CPU_FTR_EMB_HV)
#endif
	DO_KVM	\intnum, SPRN_SRR1
	std	r16,PACA_EXTLB+EX_TLB_R16(r13)
	mfspr	r16,\addr		/* get faulting address */
	std	r14,PACA_EXTLB+EX_TLB_R14(r13)
	ld	r14,PACAPGD(r13)
	std	r15,PACA_EXTLB+EX_TLB_R15(r13)
	std	r10,PACA_EXTLB+EX_TLB_CR(r13)
	TLB_MISS_PROLOG_STATS_BOLTED
.endm

.macro tlb_epilog_bolted
	ld	r14,PACA_EXTLB+EX_TLB_CR(r13)
	ld	r10,PACA_EXTLB+EX_TLB_R10(r13)
	ld	r11,PACA_EXTLB+EX_TLB_R11(r13)
	mtcr	r14
	ld	r14,PACA_EXTLB+EX_TLB_R14(r13)
	ld	r15,PACA_EXTLB+EX_TLB_R15(r13)
	TLB_MISS_RESTORE_STATS_BOLTED
	ld	r16,PACA_EXTLB+EX_TLB_R16(r13)
	mfspr	r13,SPRN_SPRG_GEN_SCRATCH
.endm

/* Data TLB miss */
	START_EXCEPTION(data_tlb_miss_bolted)
	tlb_prolog_bolted BOOKE_INTERRUPT_DTLB_MISS SPRN_DEAR

	/* We need _PAGE_PRESENT and  _PAGE_ACCESSED set */

	/* We do the user/kernel test for the PID here along with the RW test
	 */
	/* We pre-test some combination of permissions to avoid double
	 * faults:
	 *
	 * We move the ESR:ST bit into the position of _PAGE_BAP_SW in the PTE
	 * ESR_ST   is 0x00800000
	 * _PAGE_BAP_SW is 0x00000010
	 * So the shift is >> 19. This tests for supervisor writeability.
	 * If the page happens to be supervisor writeable and not user
	 * writeable, we will take a new fault later, but that should be
	 * a rare enough case.
	 *
	 * We also move ESR_ST in _PAGE_DIRTY position
	 * _PAGE_DIRTY is 0x00001000 so the shift is >> 11
	 *
	 * MAS1 is preset for all we need except for TID that needs to
	 * be cleared for kernel translations
	 */

	mfspr	r11,SPRN_ESR

	srdi	r15,r16,60		/* get region */
	rldicl.	r10,r16,64-PGTABLE_EADDR_SIZE,PGTABLE_EADDR_SIZE+4
	bne-	dtlb_miss_fault_bolted	/* Bail if fault addr is invalid */

	rlwinm	r10,r11,32-19,27,27
	rlwimi	r10,r11,32-16,19,19
	cmpwi	r15,0			/* user vs kernel check */
	ori	r10,r10,_PAGE_PRESENT
	oris	r11,r10,_PAGE_ACCESSED@h

	TLB_MISS_STATS_SAVE_INFO_BOLTED
	bne	tlb_miss_kernel_bolted

tlb_miss_common_bolted:
/*
 * This is the guts of the TLB miss handler for bolted-linear.
 * We are entered with:
 *
 * r16 = faulting address
 * r15 = crap (free to use)
 * r14 = page table base
 * r13 = PACA
 * r11 = PTE permission mask
 * r10 = crap (free to use)
 */
	rldicl	r15,r16,64-PGDIR_SHIFT+3,64-PGD_INDEX_SIZE-3
	cmpldi	cr0,r14,0
	clrrdi	r15,r15,3
	beq	tlb_miss_fault_bolted	/* No PGDIR, bail */

BEGIN_MMU_FTR_SECTION
	/* Set the TLB reservation and search for existing entry. Then load
	 * the entry.
	 */
	PPC_TLBSRX_DOT(0,R16)
	ldx	r14,r14,r15		/* grab pgd entry */
	beq	tlb_miss_done_bolted	/* tlb exists already, bail */
MMU_FTR_SECTION_ELSE
	ldx	r14,r14,r15		/* grab pgd entry */
ALT_MMU_FTR_SECTION_END_IFSET(MMU_FTR_USE_TLBRSRV)

#ifndef CONFIG_PPC_64K_PAGES
	rldicl	r15,r16,64-PUD_SHIFT+3,64-PUD_INDEX_SIZE-3
	clrrdi	r15,r15,3
	cmpdi	cr0,r14,0
	bge	tlb_miss_fault_bolted	/* Bad pgd entry or hugepage; bail */
	ldx	r14,r14,r15		/* grab pud entry */
#endif /* CONFIG_PPC_64K_PAGES */

	rldicl	r15,r16,64-PMD_SHIFT+3,64-PMD_INDEX_SIZE-3
	clrrdi	r15,r15,3
	cmpdi	cr0,r14,0
	bge	tlb_miss_fault_bolted
	ldx	r14,r14,r15		/* Grab pmd entry */

	rldicl	r15,r16,64-PAGE_SHIFT+3,64-PTE_INDEX_SIZE-3
	clrrdi	r15,r15,3
	cmpdi	cr0,r14,0
	bge	tlb_miss_fault_bolted
	ldx	r14,r14,r15		/* Grab PTE, normal (!huge) page */

	/* Check if required permissions are met */
	andc.	r15,r11,r14
	rldicr	r15,r14,64-(PTE_RPN_SHIFT-PAGE_SHIFT),63-PAGE_SHIFT
	bne-	tlb_miss_fault_bolted

	/* Now we build the MAS:
	 *
	 * MAS 0   :	Fully setup with defaults in MAS4 and TLBnCFG
	 * MAS 1   :	Almost fully setup
	 *               - PID already updated by caller if necessary
	 *               - TSIZE need change if !base page size, not
	 *                 yet implemented for now
	 * MAS 2   :	Defaults not useful, need to be redone
	 * MAS 3+7 :	Needs to be done
	 */
	clrrdi	r11,r16,12		/* Clear low crap in EA */
	clrldi	r15,r15,12		/* Clear crap at the top */
	rlwimi	r11,r14,32-19,27,31	/* Insert WIMGE */
	rlwimi	r15,r14,32-8,22,25	/* Move in U bits */
	mtspr	SPRN_MAS2,r11
	andi.	r11,r14,_PAGE_DIRTY
	rlwimi	r15,r14,32-2,26,31	/* Move in BAP bits */

	/* Mask out SW and UW if !DIRTY (XXX optimize this !) */
	bne	1f
	li	r11,MAS3_SW|MAS3_UW
	andc	r15,r15,r11
1:
	mtspr	SPRN_MAS7_MAS3,r15
	tlbwe

tlb_miss_done_bolted:
	TLB_MISS_STATS_X(MMSTAT_TLB_MISS_NORM_OK)
	tlb_epilog_bolted
	rfi

itlb_miss_kernel_bolted: