Subversion Repositories or1k_soc_on_altera_embedded_dev_kit

/*
 * Kernel execution entry point code.
 *
 *    Copyright (c) 1995-1996 Gary Thomas <gdt@linuxppc.org>
 *      Initial PowerPC version.
 *    Copyright (c) 1996 Cort Dougan <cort@cs.nmt.edu>
 *      Rewritten for PReP
 *    Copyright (c) 1996 Paul Mackerras <paulus@cs.anu.edu.au>
 *      Low-level exception handers, MMU support, and rewrite.
 *    Copyright (c) 1997 Dan Malek <dmalek@jlc.net>
 *      PowerPC 8xx modifications.
 *    Copyright (c) 1998-1999 TiVo, Inc.
 *      PowerPC 403GCX modifications.
 *    Copyright (c) 1999 Grant Erickson <grant@lcse.umn.edu>
 *      PowerPC 403GCX/405GP modifications.
 *    Copyright 2000 MontaVista Software Inc.
 *      PPC405 modifications
 *      PowerPC 403GCX/405GP modifications.
 *      Author: MontaVista Software, Inc.
 *              frank_rowand@mvista.com or source@mvista.com
 *              debbie_chu@mvista.com
 *    Copyright 2002-2004 MontaVista Software, Inc.
 *      PowerPC 44x support, Matt Porter <mporter@kernel.crashing.org>
 *    Copyright 2004 Freescale Semiconductor, Inc
 *      PowerPC e500 modifications, Kumar Gala <galak@kernel.crashing.org>
 *
 * 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 <linux/threads.h>
#include <asm/processor.h>
#include <asm/page.h>
#include <asm/mmu.h>
#include <asm/pgtable.h>
#include <asm/cputable.h>
#include <asm/thread_info.h>
#include <asm/ppc_asm.h>
#include <asm/asm-offsets.h>
#include "head_booke.h"

/* As with the other PowerPC ports, it is expected that when code
 * execution begins here, the following registers contain valid, yet
 * optional, information:
 *
 *   r3 - Board info structure pointer (DRAM, frequency, MAC address, etc.)
 *   r4 - Starting address of the init RAM disk
 *   r5 - Ending address of the init RAM disk
 *   r6 - Start of kernel command line string (e.g. "mem=128")
 *   r7 - End of kernel command line string
 *
 */
        .section        .text.head, "ax"
_ENTRY(_stext);
_ENTRY(_start);
        /*
         * Reserve a word at a fixed location to store the address
         * of abatron_pteptrs
         */
        nop
/*
 * Save parameters we are passed
 */
        mr      r31,r3
        mr      r30,r4
        mr      r29,r5
        mr      r28,r6
        mr      r27,r7
        li      r24,0           /* CPU number */

/* We try to not make any assumptions about how the boot loader
 * setup or used the TLBs.  We invalidate all mappings from the
 * boot loader and load a single entry in TLB1[0] to map the
 * first 16M of kernel memory.  Any boot info passed from the
 * bootloader needs to live in this first 16M.
 *
 * Requirement on bootloader:
 *  - The page we're executing in needs to reside in TLB1 and
 *    have IPROT=1.  If not an invalidate broadcast could
 *    evict the entry we're currently executing in.
 *
 *  r3 = Index of TLB1 were executing in
 *  r4 = Current MSR[IS]
 *  r5 = Index of TLB1 temp mapping
 *
 * Later in mapin_ram we will correctly map lowmem, and resize TLB1[0]
 * if needed
 */

/* 1. Find the index of the entry we're executing in */
        bl      invstr                          /* Find our address */
invstr: mflr    r6                              /* Make it accessible */
        mfmsr   r7
        rlwinm  r4,r7,27,31,31                  /* extract MSR[IS] */
        mfspr   r7, SPRN_PID0
        slwi    r7,r7,16
        or      r7,r7,r4
        mtspr   SPRN_MAS6,r7
        tlbsx   0,r6                            /* search MSR[IS], SPID=PID0 */
#ifndef CONFIG_E200
        mfspr   r7,SPRN_MAS1
        andis.  r7,r7,MAS1_VALID@h
        bne     match_TLB
        mfspr   r7,SPRN_PID1
        slwi    r7,r7,16
        or      r7,r7,r4
        mtspr   SPRN_MAS6,r7
        tlbsx   0,r6                            /* search MSR[IS], SPID=PID1 */
        mfspr   r7,SPRN_MAS1
        andis.  r7,r7,MAS1_VALID@h
        bne     match_TLB
        mfspr   r7, SPRN_PID2
        slwi    r7,r7,16
        or      r7,r7,r4
        mtspr   SPRN_MAS6,r7
        tlbsx   0,r6                            /* Fall through, we had to match */
#endif
match_TLB:
        mfspr   r7,SPRN_MAS0
        rlwinm  r3,r7,16,20,31                  /* Extract MAS0(Entry) */

        mfspr   r7,SPRN_MAS1                    /* Insure IPROT set */
        oris    r7,r7,MAS1_IPROT@h
        mtspr   SPRN_MAS1,r7
        tlbwe

/* 2. Invalidate all entries except the entry we're executing in */
        mfspr   r9,SPRN_TLB1CFG
        andi.   r9,r9,0xfff
        li      r6,0                            /* Set Entry counter to 0 */
1:      lis     r7,0x1000                       /* Set MAS0(TLBSEL) = 1 */
        rlwimi  r7,r6,16,4,15                   /* Setup MAS0 = TLBSEL | ESEL(r6) */
        mtspr   SPRN_MAS0,r7
        tlbre
        mfspr   r7,SPRN_MAS1
        rlwinm  r7,r7,0,2,31                    /* Clear MAS1 Valid and IPROT */
        cmpw    r3,r6
        beq     skpinv                          /* Dont update the current execution TLB */
        mtspr   SPRN_MAS1,r7
        tlbwe
        isync
skpinv: addi    r6,r6,1                         /* Increment */
        cmpw    r6,r9                           /* Are we done? */
        bne     1b                              /* If not, repeat */

        /* Invalidate TLB0 */
        li      r6,0x04
        tlbivax 0,r6
#ifdef CONFIG_SMP
        tlbsync
#endif
        /* Invalidate TLB1 */
        li      r6,0x0c
        tlbivax 0,r6
#ifdef CONFIG_SMP
        tlbsync
#endif
        msync

/* 3. Setup a temp mapping and jump to it */
        andi.   r5, r3, 0x1     /* Find an entry not used and is non-zero */
        addi    r5, r5, 0x1
        lis     r7,0x1000       /* Set MAS0(TLBSEL) = 1 */
        rlwimi  r7,r3,16,4,15   /* Setup MAS0 = TLBSEL | ESEL(r3) */
        mtspr   SPRN_MAS0,r7
        tlbre

        /* Just modify the entry ID and EPN for the temp mapping */
        lis     r7,0x1000       /* Set MAS0(TLBSEL) = 1 */
        rlwimi  r7,r5,16,4,15   /* Setup MAS0 = TLBSEL | ESEL(r5) */
        mtspr   SPRN_MAS0,r7
        xori    r6,r4,1         /* Setup TMP mapping in the other Address space */
        slwi    r6,r6,12
        oris    r6,r6,(MAS1_VALID|MAS1_IPROT)@h
        ori     r6,r6,(MAS1_TSIZE(BOOKE_PAGESZ_4K))@l
        mtspr   SPRN_MAS1,r6
        mfspr   r6,SPRN_MAS2
        li      r7,0            /* temp EPN = 0 */
        rlwimi  r7,r6,0,20,31
        mtspr   SPRN_MAS2,r7
        tlbwe

        xori    r6,r4,1
        slwi    r6,r6,5         /* setup new context with other address space */
        bl      1f              /* Find our address */
1:      mflr    r9
        rlwimi  r7,r9,0,20,31
        addi    r7,r7,24
        mtspr   SPRN_SRR0,r7
        mtspr   SPRN_SRR1,r6
        rfi

/* 4. Clear out PIDs & Search info */
        li      r6,0
        mtspr   SPRN_PID0,r6
#ifndef CONFIG_E200
        mtspr   SPRN_PID1,r6
        mtspr   SPRN_PID2,r6
#endif
        mtspr   SPRN_MAS6,r6

/* 5. Invalidate mapping we started in */
        lis     r7,0x1000       /* Set MAS0(TLBSEL) = 1 */
        rlwimi  r7,r3,16,4,15   /* Setup MAS0 = TLBSEL | ESEL(r3) */
        mtspr   SPRN_MAS0,r7
        tlbre
        mfspr   r6,SPRN_MAS1
        rlwinm  r6,r6,0,2,0     /* clear IPROT */
        mtspr   SPRN_MAS1,r6
        tlbwe
        /* Invalidate TLB1 */
        li      r9,0x0c
        tlbivax 0,r9
#ifdef CONFIG_SMP
        tlbsync
#endif
        msync

/* 6. Setup KERNELBASE mapping in TLB1[0] */
        lis     r6,0x1000               /* Set MAS0(TLBSEL) = TLB1(1), ESEL = 0 */
        mtspr   SPRN_MAS0,r6
        lis     r6,(MAS1_VALID|MAS1_IPROT)@h
        ori     r6,r6,(MAS1_TSIZE(BOOKE_PAGESZ_16M))@l
        mtspr   SPRN_MAS1,r6
        li      r7,0
        lis     r6,KERNELBASE@h
        ori     r6,r6,KERNELBASE@l
        rlwimi  r6,r7,0,20,31
        mtspr   SPRN_MAS2,r6
        li      r7,(MAS3_SX|MAS3_SW|MAS3_SR)
        mtspr   SPRN_MAS3,r7
        tlbwe

/* 7. Jump to KERNELBASE mapping */
        lis     r7,MSR_KERNEL@h
        ori     r7,r7,MSR_KERNEL@l
        bl      1f                      /* Find our address */
1:      mflr    r9
        rlwimi  r6,r9,0,20,31
        addi    r6,r6,24
        mtspr   SPRN_SRR0,r6
        mtspr   SPRN_SRR1,r7
        rfi                             /* start execution out of TLB1[0] entry */

/* 8. Clear out the temp mapping */
        lis     r7,0x1000       /* Set MAS0(TLBSEL) = 1 */
        rlwimi  r7,r5,16,4,15   /* Setup MAS0 = TLBSEL | ESEL(r5) */
        mtspr   SPRN_MAS0,r7
        tlbre
        mfspr   r8,SPRN_MAS1
        rlwinm  r8,r8,0,2,0     /* clear IPROT */
        mtspr   SPRN_MAS1,r8
        tlbwe
        /* Invalidate TLB1 */
        li      r9,0x0c
        tlbivax 0,r9
#ifdef CONFIG_SMP
        tlbsync
#endif
        msync

        /* Establish the interrupt vector offsets */
        SET_IVOR(0,  CriticalInput);
        SET_IVOR(1,  MachineCheck);
        SET_IVOR(2,  DataStorage);
        SET_IVOR(3,  InstructionStorage);
        SET_IVOR(4,  ExternalInput);
        SET_IVOR(5,  Alignment);
        SET_IVOR(6,  Program);
        SET_IVOR(7,  FloatingPointUnavailable);
        SET_IVOR(8,  SystemCall);
        SET_IVOR(9,  AuxillaryProcessorUnavailable);
        SET_IVOR(10, Decrementer);
        SET_IVOR(11, FixedIntervalTimer);
        SET_IVOR(12, WatchdogTimer);
        SET_IVOR(13, DataTLBError);
        SET_IVOR(14, InstructionTLBError);
        SET_IVOR(15, Debug);
        SET_IVOR(32, SPEUnavailable);
        SET_IVOR(33, SPEFloatingPointData);
        SET_IVOR(34, SPEFloatingPointRound);
#ifndef CONFIG_E200
        SET_IVOR(35, PerformanceMonitor);
#endif

        /* Establish the interrupt vector base */
        lis     r4,interrupt_base@h     /* IVPR only uses the high 16-bits */
        mtspr   SPRN_IVPR,r4

        /* Setup the defaults for TLB entries */
        li      r2,(MAS4_TSIZED(BOOKE_PAGESZ_4K))@l
#ifdef CONFIG_E200
        oris    r2,r2,MAS4_TLBSELD(1)@h
#endif
        mtspr   SPRN_MAS4, r2

#if 0
        /* Enable DOZE */
        mfspr   r2,SPRN_HID0
        oris    r2,r2,HID0_DOZE@h
        mtspr   SPRN_HID0, r2
#endif
#ifdef CONFIG_E200
        /* enable dedicated debug exception handling resources (Debug APU) */
        mfspr   r2,SPRN_HID0
        ori     r2,r2,HID0_DAPUEN@l
        mtspr   SPRN_HID0,r2
#endif

#if !defined(CONFIG_BDI_SWITCH)
        /*
         * The Abatron BDI JTAG debugger does not tolerate others
         * mucking with the debug registers.
         */
        lis     r2,DBCR0_IDM@h
        mtspr   SPRN_DBCR0,r2
        isync
        /* clear any residual debug events */
        li      r2,-1
        mtspr   SPRN_DBSR,r2
#endif

        /*
         * This is where the main kernel code starts.
         */

        /* ptr to current */
        lis     r2,init_task@h
        ori     r2,r2,init_task@l

        /* ptr to current thread */
        addi    r4,r2,THREAD    /* init task's THREAD */
        mtspr   SPRN_SPRG3,r4

        /* stack */
        lis     r1,init_thread_union@h
        ori     r1,r1,init_thread_union@l
        li      r0,0
        stwu    r0,THREAD_SIZE-STACK_FRAME_OVERHEAD(r1)

        bl      early_init

        mfspr   r3,SPRN_TLB1CFG
        andi.   r3,r3,0xfff
        lis     r4,num_tlbcam_entries@ha
        stw     r3,num_tlbcam_entries@l(r4)
/*
 * Decide what sort of machine this is and initialize the MMU.
 */
        mr      r3,r31
        mr      r4,r30
        mr      r5,r29
        mr      r6,r28
        mr      r7,r27
        bl      machine_init
        bl      MMU_init

        /* Setup PTE pointers for the Abatron bdiGDB */
        lis     r6, swapper_pg_dir@h
        ori     r6, r6, swapper_pg_dir@l
        lis     r5, abatron_pteptrs@h
        ori     r5, r5, abatron_pteptrs@l
        lis     r4, KERNELBASE@h
        ori     r4, r4, KERNELBASE@l
        stw     r5, 0(r4)       /* Save abatron_pteptrs at a fixed location */
        stw     r6, 0(r5)

        /* Let's move on */
        lis     r4,start_kernel@h
        ori     r4,r4,start_kernel@l
        lis     r3,MSR_KERNEL@h
        ori     r3,r3,MSR_KERNEL@l
        mtspr   SPRN_SRR0,r4
        mtspr   SPRN_SRR1,r3
        rfi                     /* change context and jump to start_kernel */

/* Macros to hide the PTE size differences
 *
 * FIND_PTE -- walks the page tables given EA & pgdir pointer
 *   r10 -- EA of fault
 *   r11 -- PGDIR pointer
 *   r12 -- free
 *   label 2: is the bailout case
 *
 * if we find the pte (fall through):
 *   r11 is low pte word
 *   r12 is pointer to the pte
 */
#ifdef CONFIG_PTE_64BIT
#define PTE_FLAGS_OFFSET        4
#define FIND_PTE        \
        rlwinm  r12, r10, 13, 19, 29;   /* Compute pgdir/pmd offset */  \
        lwzx    r11, r12, r11;          /* Get pgd/pmd entry */         \
        rlwinm. r12, r11, 0, 0, 20;     /* Extract pt base address */   \
        beq     2f;                     /* Bail if no table */          \
        rlwimi  r12, r10, 23, 20, 28;   /* Compute pte address */       \
        lwz     r11, 4(r12);            /* Get pte entry */
#else
#define PTE_FLAGS_OFFSET        0
#define FIND_PTE        \
        rlwimi  r11, r10, 12, 20, 29;   /* Create L1 (pgdir/pmd) address */     \
        lwz     r11, 0(r11);            /* Get L1 entry */                      \
        rlwinm. r12, r11, 0, 0, 19;     /* Extract L2 (pte) base address */     \
        beq     2f;                     /* Bail if no table */                  \
        rlwimi  r12, r10, 22, 20, 29;   /* Compute PTE address */               \
        lwz     r11, 0(r12);            /* Get Linux PTE */
#endif

/*
 * Interrupt vector entry code
 *
 * The Book E MMUs are always on so we don't need to handle
 * interrupts in real mode as with previous PPC processors. In
 * this case we handle interrupts in the kernel virtual address
 * space.
 *
 * Interrupt vectors are dynamically placed relative to the
 * interrupt prefix as determined by the address of interrupt_base.
 * The interrupt vectors offsets are programmed using the labels
 * for each interrupt vector entry.
 *
 * Interrupt vectors must be aligned on a 16 byte boundary.
 * We align on a 32 byte cache line boundary for good measure.
 */

interrupt_base:
        /* Critical Input Interrupt */
        CRITICAL_EXCEPTION(0x0100, CriticalInput, unknown_exception)

        /* Machine Check Interrupt */
#ifdef CONFIG_E200
        /* no RFMCI, MCSRRs on E200 */
        CRITICAL_EXCEPTION(0x0200, MachineCheck, machine_check_exception)
#else
        MCHECK_EXCEPTION(0x0200, MachineCheck, machine_check_exception)
#endif

        /* Data Storage Interrupt */
        START_EXCEPTION(DataStorage)
        mtspr   SPRN_SPRG0, r10         /* Save some working registers */
        mtspr   SPRN_SPRG1, r11
        mtspr   SPRN_SPRG4W, r12
        mtspr   SPRN_SPRG5W, r13
        mfcr    r11
        mtspr   SPRN_SPRG7W, r11

        /*
         * Check if it was a store fault, if not then bail
         * because a user tried to access a kernel or
         * read-protected page.  Otherwise, get the
         * offending address and handle it.
         */
        mfspr   r10, SPRN_ESR
        andis.  r10, r10, ESR_ST@h
        beq     2f

        mfspr   r10, SPRN_DEAR          /* Get faulting address */

        /* If we are faulting a kernel address, we have to use the
         * kernel page tables.
         */
        lis     r11, PAGE_OFFSET@h
        cmplw   0, r10, r11
        bge     2f

        /* Get the PGD for the current thread */
3:
        mfspr   r11,SPRN_SPRG3
        lwz     r11,PGDIR(r11)
4:
        FIND_PTE

        /* Are _PAGE_USER & _PAGE_RW set & _PAGE_HWWRITE not? */
        andi.   r13, r11, _PAGE_RW|_PAGE_USER|_PAGE_HWWRITE
        cmpwi   0, r13, _PAGE_RW|_PAGE_USER
        bne     2f                      /* Bail if not */

        /* Update 'changed'. */
        ori     r11, r11, _PAGE_DIRTY|_PAGE_ACCESSED|_PAGE_HWWRITE
        stw     r11, PTE_FLAGS_OFFSET(r12) /* Update Linux page table */

        /* MAS2 not updated as the entry does exist in the tlb, this
           fault taken to detect state transition (eg: COW -> DIRTY)
         */
        andi.   r11, r11, _PAGE_HWEXEC
        rlwimi  r11, r11, 31, 27, 27    /* SX <- _PAGE_HWEXEC */
        ori     r11, r11, (MAS3_UW|MAS3_SW|MAS3_UR|MAS3_SR)@l /* set static perms */

        /* update search PID in MAS6, AS = 0 */
        mfspr   r12, SPRN_PID0
        slwi    r12, r12, 16
        mtspr   SPRN_MAS6, r12

        /* find the TLB index that caused the fault.  It has to be here. */
        tlbsx   0, r10

        /* only update the perm bits, assume the RPN is fine */
        mfspr   r12, SPRN_MAS3
        rlwimi  r12, r11, 0, 20, 31
        mtspr   SPRN_MAS3,r12
        tlbwe

        /* Done...restore registers and get out of here.  */
        mfspr   r11, SPRN_SPRG7R
        mtcr    r11
        mfspr   r13, SPRN_SPRG5R
        mfspr   r12, SPRN_SPRG4R
        mfspr   r11, SPRN_SPRG1
        mfspr   r10, SPRN_SPRG0
        rfi                     /* Force context change */

2:
        /*
         * The bailout.  Restore registers to pre-exception conditions
         * and call the heavyweights to help us out.
         */
        mfspr   r11, SPRN_SPRG7R
        mtcr    r11
        mfspr   r13, SPRN_SPRG5R
        mfspr   r12, SPRN_SPRG4R
        mfspr   r11, SPRN_SPRG1
        mfspr   r10, SPRN_SPRG0
        b       data_access

        /* Instruction Storage Interrupt */
        INSTRUCTION_STORAGE_EXCEPTION

        /* External Input Interrupt */
        EXCEPTION(0x0500, ExternalInput, do_IRQ, EXC_XFER_LITE)

        /* Alignment Interrupt */
        ALIGNMENT_EXCEPTION

        /* Program Interrupt */
        PROGRAM_EXCEPTION

        /* Floating Point Unavailable Interrupt */
#ifdef CONFIG_PPC_FPU
        FP_UNAVAILABLE_EXCEPTION
#else
#ifdef CONFIG_E200
        /* E200 treats 'normal' floating point instructions as FP Unavail exception */
        EXCEPTION(0x0800, FloatingPointUnavailable, program_check_exception, EXC_XFER_EE)
#else
        EXCEPTION(0x0800, FloatingPointUnavailable, unknown_exception, EXC_XFER_EE)
#endif
#endif

        /* System Call Interrupt */
        START_EXCEPTION(SystemCall)
        NORMAL_EXCEPTION_PROLOG
        EXC_XFER_EE_LITE(0x0c00, DoSyscall)

        /* Auxillary Processor Unavailable Interrupt */
        EXCEPTION(0x2900, AuxillaryProcessorUnavailable, unknown_exception, EXC_XFER_EE)

        /* Decrementer Interrupt */
        DECREMENTER_EXCEPTION

        /* Fixed Internal Timer Interrupt */
        /* TODO: Add FIT support */
        EXCEPTION(0x3100, FixedIntervalTimer, unknown_exception, EXC_XFER_EE)

        /* Watchdog Timer Interrupt */
#ifdef CONFIG_BOOKE_WDT
        CRITICAL_EXCEPTION(0x3200, WatchdogTimer, WatchdogException)
#else
        CRITICAL_EXCEPTION(0x3200, WatchdogTimer, unknown_exception)
#endif

        /* Data TLB Error Interrupt */
        START_EXCEPTION(DataTLBError)
        mtspr   SPRN_SPRG0, r10         /* Save some working registers */
        mtspr   SPRN_SPRG1, r11
        mtspr   SPRN_SPRG4W, r12
        mtspr   SPRN_SPRG5W, r13
        mfcr    r11
        mtspr   SPRN_SPRG7W, r11
        mfspr   r10, SPRN_DEAR          /* Get faulting address */

        /* If we are faulting a kernel address, we have to use the
         * kernel page tables.
         */
        lis     r11, PAGE_OFFSET@h
        cmplw   5, r10, r11
        blt     5, 3f
        lis     r11, swapper_pg_dir@h
        ori     r11, r11, swapper_pg_dir@l

        mfspr   r12,SPRN_MAS1           /* Set TID to 0 */
        rlwinm  r12,r12,0,16,1
        mtspr   SPRN_MAS1,r12

        b       4f

        /* Get the PGD for the current thread */
3:
        mfspr   r11,SPRN_SPRG3
        lwz     r11,PGDIR(r11)

4:
        FIND_PTE
        andi.   r13, r11, _PAGE_PRESENT /* Is the page present? */
        beq     2f                      /* Bail if not present */

#ifdef CONFIG_PTE_64BIT
        lwz     r13, 0(r12)
#endif
        ori     r11, r11, _PAGE_ACCESSED
        stw     r11, PTE_FLAGS_OFFSET(r12)

         /* Jump to common tlb load */
        b       finish_tlb_load
2:
        /* The bailout.  Restore registers to pre-exception conditions
         * and call the heavyweights to help us out.
         */
        mfspr   r11, SPRN_SPRG7R
        mtcr    r11
        mfspr   r13, SPRN_SPRG5R
        mfspr   r12, SPRN_SPRG4R
        mfspr   r11, SPRN_SPRG1
        mfspr   r10, SPRN_SPRG0
        b       data_access

        /* Instruction TLB Error Interrupt */
        /*
         * Nearly the same as above, except we get our
         * information from different registers and bailout
         * to a different point.
         */
        START_EXCEPTION(InstructionTLBError)
        mtspr   SPRN_SPRG0, r10         /* Save some working registers */
        mtspr   SPRN_SPRG1, r11
        mtspr   SPRN_SPRG4W, r12
        mtspr   SPRN_SPRG5W, r13
        mfcr    r11
        mtspr   SPRN_SPRG7W, r11
        mfspr   r10, SPRN_SRR0          /* Get faulting address */

        /* If we are faulting a kernel address, we have to use the
         * kernel page tables.
         */
        lis     r11, PAGE_OFFSET@h
        cmplw   5, r10, r11
        blt     5, 3f
        lis     r11, swapper_pg_dir@h
        ori     r11, r11, swapper_pg_dir@l

        mfspr   r12,SPRN_MAS1           /* Set TID to 0 */
        rlwinm  r12,r12,0,16,1
        mtspr   SPRN_MAS1,r12

        b       4f

        /* Get the PGD for the current thread */
3:
        mfspr   r11,SPRN_SPRG3
        lwz     r11,PGDIR(r11)

4:
        FIND_PTE
        andi.   r13, r11, _PAGE_PRESENT /* Is the page present? */
        beq     2f                      /* Bail if not present */

#ifdef CONFIG_PTE_64BIT
        lwz     r13, 0(r12)
#endif
        ori     r11, r11, _PAGE_ACCESSED
        stw     r11, PTE_FLAGS_OFFSET(r12)

        /* Jump to common TLB load point */
        b       finish_tlb_load

2:
        /* The bailout.  Restore registers to pre-exception conditions
         * and call the heavyweights to help us out.
         */
        mfspr   r11, SPRN_SPRG7R
        mtcr    r11
        mfspr   r13, SPRN_SPRG5R
        mfspr   r12, SPRN_SPRG4R
        mfspr   r11, SPRN_SPRG1
        mfspr   r10, SPRN_SPRG0
        b       InstructionStorage

#ifdef CONFIG_SPE
        /* SPE Unavailable */
        START_EXCEPTION(SPEUnavailable)
        NORMAL_EXCEPTION_PROLOG
        bne     load_up_spe
        addi    r3,r1,STACK_FRAME_OVERHEAD
        EXC_XFER_EE_LITE(0x2010, KernelSPE)
#else
        EXCEPTION(0x2020, SPEUnavailable, unknown_exception, EXC_XFER_EE)
#endif /* CONFIG_SPE */

        /* SPE Floating Point Data */
#ifdef CONFIG_SPE
        EXCEPTION(0x2030, SPEFloatingPointData, SPEFloatingPointException, EXC_XFER_EE);
#else
        EXCEPTION(0x2040, SPEFloatingPointData, unknown_exception, EXC_XFER_EE)
#endif /* CONFIG_SPE */

        /* SPE Floating Point Round */
        EXCEPTION(0x2050, SPEFloatingPointRound, unknown_exception, EXC_XFER_EE)

        /* Performance Monitor */
        EXCEPTION(0x2060, PerformanceMonitor, performance_monitor_exception, EXC_XFER_STD)


        /* Debug Interrupt */
        DEBUG_EXCEPTION

/*
 * Local functions
 */

        /*
         * Data TLB exceptions will bail out to this point
         * if they can't resolve the lightweight TLB fault.
         */
data_access:
        NORMAL_EXCEPTION_PROLOG
        mfspr   r5,SPRN_ESR             /* Grab the ESR, save it, pass arg3 */
        stw     r5,_ESR(r11)
        mfspr   r4,SPRN_DEAR            /* Grab the DEAR, save it, pass arg2 */
        andis.  r10,r5,(ESR_ILK|ESR_DLK)@h
        bne     1f
        EXC_XFER_EE_LITE(0x0300, handle_page_fault)
1:
        addi    r3,r1,STACK_FRAME_OVERHEAD
        EXC_XFER_EE_LITE(0x0300, CacheLockingException)

/*

 * Both the instruction and data TLB miss get to this
 * point to load the TLB.
 *      r10 - EA of fault
 *      r11 - TLB (info from Linux PTE)
 *      r12, r13 - available to use
 *      CR5 - results of addr >= PAGE_OFFSET
 *      MAS0, MAS1 - loaded with proper value when we get here
 *      MAS2, MAS3 - will need additional info from Linux PTE
 *      Upon exit, we reload everything and RFI.
 */
finish_tlb_load:
        /*
         * We set execute, because we don't have the granularity to
         * properly set this at the page level (Linux problem).
         * Many of these bits are software only.  Bits we don't set
         * here we (properly should) assume have the appropriate value.
         */

        mfspr   r12, SPRN_MAS2
#ifdef CONFIG_PTE_64BIT
        rlwimi  r12, r11, 26, 24, 31    /* extract ...WIMGE from pte */
#else
        rlwimi  r12, r11, 26, 27, 31    /* extract WIMGE from pte */
#endif
        mtspr   SPRN_MAS2, r12

        bge     5, 1f

        /* is user addr */
        andi.   r12, r11, (_PAGE_USER | _PAGE_HWWRITE | _PAGE_HWEXEC)
        andi.   r10, r11, _PAGE_USER    /* Test for _PAGE_USER */
        srwi    r10, r12, 1
        or      r12, r12, r10   /* Copy user perms into supervisor */
        iseleq  r12, 0, r12
        b       2f

        /* is kernel addr */
1:      rlwinm  r12, r11, 31, 29, 29    /* Extract _PAGE_HWWRITE into SW */
        ori     r12, r12, (MAS3_SX | MAS3_SR)

#ifdef CONFIG_PTE_64BIT
2:      rlwimi  r12, r13, 24, 0, 7      /* grab RPN[32:39] */
        rlwimi  r12, r11, 24, 8, 19     /* grab RPN[40:51] */
        mtspr   SPRN_MAS3, r12
BEGIN_FTR_SECTION
        srwi    r10, r13, 8             /* grab RPN[8:31] */
        mtspr   SPRN_MAS7, r10
END_FTR_SECTION_IFSET(CPU_FTR_BIG_PHYS)
#else
2:      rlwimi  r11, r12, 0, 20, 31     /* Extract RPN from PTE and merge with perms */
        mtspr   SPRN_MAS3, r11
#endif
#ifdef CONFIG_E200
        /* Round robin TLB1 entries assignment */
        mfspr   r12, SPRN_MAS0

        /* Extract TLB1CFG(NENTRY) */
        mfspr   r11, SPRN_TLB1CFG
        andi.   r11, r11, 0xfff

        /* Extract MAS0(NV) */
        andi.   r13, r12, 0xfff
        addi    r13, r13, 1
        cmpw    0, r13, r11
        addi    r12, r12, 1

        /* check if we need to wrap */
        blt     7f

        /* wrap back to first free tlbcam entry */
        lis     r13, tlbcam_index@ha
        lwz     r13, tlbcam_index@l(r13)
        rlwimi  r12, r13, 0, 20, 31
7:
        mtspr   SPRN_MAS0,r12
#endif /* CONFIG_E200 */

        tlbwe

        /* Done...restore registers and get out of here.  */
        mfspr   r11, SPRN_SPRG7R
        mtcr    r11
        mfspr   r13, SPRN_SPRG5R
        mfspr   r12, SPRN_SPRG4R
        mfspr   r11, SPRN_SPRG1
        mfspr   r10, SPRN_SPRG0
        rfi                                     /* Force context change */

#ifdef CONFIG_SPE
/* Note that the SPE support is closely modeled after the AltiVec
 * support.  Changes to one are likely to be applicable to the
 * other!  */
load_up_spe:
/*
 * Disable SPE for the task which had SPE previously,
 * and save its SPE registers in its thread_struct.
 * Enables SPE for use in the kernel on return.
 * On SMP we know the SPE units are free, since we give it up every
 * switch.  -- Kumar
 */
        mfmsr   r5
        oris    r5,r5,MSR_SPE@h
        mtmsr   r5                      /* enable use of SPE now */
        isync
/*
 * For SMP, we don't do lazy SPE switching because it just gets too
 * horrendously complex, especially when a task switches from one CPU
 * to another.  Instead we call giveup_spe in switch_to.
 */
#ifndef CONFIG_SMP
        lis     r3,last_task_used_spe@ha
        lwz     r4,last_task_used_spe@l(r3)
        cmpi    0,r4,0
        beq     1f
        addi    r4,r4,THREAD    /* want THREAD of last_task_used_spe */
        SAVE_32EVRS(0,r10,r4)
        evxor   evr10, evr10, evr10     /* clear out evr10 */
        evmwumiaa evr10, evr10, evr10   /* evr10 <- ACC = 0 * 0 + ACC */
        li      r5,THREAD_ACC
        evstddx evr10, r4, r5           /* save off accumulator */
        lwz     r5,PT_REGS(r4)
        lwz     r4,_MSR-STACK_FRAME_OVERHEAD(r5)
        lis     r10,MSR_SPE@h
        andc    r4,r4,r10       /* disable SPE for previous task */
        stw     r4,_MSR-STACK_FRAME_OVERHEAD(r5)
1:
#endif /* !CONFIG_SMP */
        /* enable use of SPE after return */
        oris    r9,r9,MSR_SPE@h
        mfspr   r5,SPRN_SPRG3           /* current task's THREAD (phys) */
        li      r4,1
        li      r10,THREAD_ACC
        stw     r4,THREAD_USED_SPE(r5)
        evlddx  evr4,r10,r5
        evmra   evr4,evr4
        REST_32EVRS(0,r10,r5)
#ifndef CONFIG_SMP
        subi    r4,r5,THREAD
        stw     r4,last_task_used_spe@l(r3)
#endif /* !CONFIG_SMP */
        /* restore registers and return */
2:      REST_4GPRS(3, r11)
        lwz     r10,_CCR(r11)
        REST_GPR(1, r11)
        mtcr    r10
        lwz     r10,_LINK(r11)
        mtlr    r10
        REST_GPR(10, r11)
        mtspr   SPRN_SRR1,r9
        mtspr   SPRN_SRR0,r12
        REST_GPR(9, r11)
        REST_GPR(12, r11)
        lwz     r11,GPR11(r11)
        rfi

/*
 * SPE unavailable trap from kernel - print a message, but let
 * the task use SPE in the kernel until it returns to user mode.
 */
KernelSPE:
        lwz     r3,_MSR(r1)
        oris    r3,r3,MSR_SPE@h
        stw     r3,_MSR(r1)     /* enable use of SPE after return */
        lis     r3,87f@h
        ori     r3,r3,87f@l
        mr      r4,r2           /* current */
        lwz     r5,_NIP(r1)
        bl      printk
        b       ret_from_except
87:     .string "SPE used in kernel  (task=%p, pc=%x)  \n"
        .align  4,0

#endif /* CONFIG_SPE */

/*
 * Global functions
 */

/*
 * extern void loadcam_entry(unsigned int index)
 *
 * Load TLBCAM[index] entry in to the L2 CAM MMU
 */
_GLOBAL(loadcam_entry)
        lis     r4,TLBCAM@ha
        addi    r4,r4,TLBCAM@l
        mulli   r5,r3,20
        add     r3,r5,r4
        lwz     r4,0(r3)
        mtspr   SPRN_MAS0,r4
        lwz     r4,4(r3)
        mtspr   SPRN_MAS1,r4
        lwz     r4,8(r3)
        mtspr   SPRN_MAS2,r4
        lwz     r4,12(r3)
        mtspr   SPRN_MAS3,r4
        tlbwe
        isync
        blr

/*
 * extern void giveup_altivec(struct task_struct *prev)
 *
 * The e500 core does not have an AltiVec unit.
 */
_GLOBAL(giveup_altivec)
        blr

#ifdef CONFIG_SPE
/*
 * extern void giveup_spe(struct task_struct *prev)
 *
 */
_GLOBAL(giveup_spe)
        mfmsr   r5
        oris    r5,r5,MSR_SPE@h
        mtmsr   r5                      /* enable use of SPE now */
        isync
        cmpi    0,r3,0
        beqlr-                          /* if no previous owner, done */
        addi    r3,r3,THREAD            /* want THREAD of task */
        lwz     r5,PT_REGS(r3)
        cmpi    0,r5,0
        SAVE_32EVRS(0, r4, r3)
        evxor   evr6, evr6, evr6        /* clear out evr6 */
        evmwumiaa evr6, evr6, evr6      /* evr6 <- ACC = 0 * 0 + ACC */
        li      r4,THREAD_ACC
        evstddx evr6, r4, r3            /* save off accumulator */
        mfspr   r6,SPRN_SPEFSCR
        stw     r6,THREAD_SPEFSCR(r3)   /* save spefscr register value */
        beq     1f
        lwz     r4,_MSR-STACK_FRAME_OVERHEAD(r5)
        lis     r3,MSR_SPE@h
        andc    r4,r4,r3                /* disable SPE for previous task */
        stw     r4,_MSR-STACK_FRAME_OVERHEAD(r5)
1:
#ifndef CONFIG_SMP
        li      r5,0
        lis     r4,last_task_used_spe@ha
        stw     r5,last_task_used_spe@l(r4)
#endif /* !CONFIG_SMP */
        blr
#endif /* CONFIG_SPE */

/*
 * extern void giveup_fpu(struct task_struct *prev)
 *
 * Not all FSL Book-E cores have an FPU
 */
#ifndef CONFIG_PPC_FPU
_GLOBAL(giveup_fpu)
        blr
#endif

/*
 * extern void abort(void)
 *
 * At present, this routine just applies a system reset.
 */
_GLOBAL(abort)
        li      r13,0
        mtspr   SPRN_DBCR0,r13          /* disable all debug events */
        isync
        mfmsr   r13
        ori     r13,r13,MSR_DE@l        /* Enable Debug Events */
        mtmsr   r13
        isync
        mfspr   r13,SPRN_DBCR0
        lis     r13,(DBCR0_IDM|DBCR0_RST_CHIP)@h
        mtspr   SPRN_DBCR0,r13
        isync

_GLOBAL(set_context)

#ifdef CONFIG_BDI_SWITCH
        /* Context switch the PTE pointer for the Abatron BDI2000.
         * The PGDIR is the second parameter.
         */
        lis     r5, abatron_pteptrs@h
        ori     r5, r5, abatron_pteptrs@l
        stw     r4, 0x4(r5)
#endif
        mtspr   SPRN_PID,r3
        isync                   /* Force context change */
        blr

/*
 * We put a few things here that have to be page-aligned. This stuff
 * goes at the beginning of the data segment, which is page-aligned.
 */
        .data
        .align  12
        .globl  sdata
sdata:
        .globl  empty_zero_page
empty_zero_page:
        .space  4096
        .globl  swapper_pg_dir
swapper_pg_dir:
        .space  PGD_TABLE_SIZE

/* Reserved 4k for the critical exception stack & 4k for the machine
 * check stack per CPU for kernel mode exceptions */
        .section .bss
        .align 12
exception_stack_bottom:
        .space  BOOKE_EXCEPTION_STACK_SIZE * NR_CPUS
        .globl  exception_stack_top
exception_stack_top:

/*
 * Room for two PTE pointers, usually the kernel and current user pointers
 * to their respective root page table.
 */
abatron_pteptrs:
        .space  8