powerpc: Merge enough to start building in arch/powerpc.

This creates the directory structure under arch/powerpc and a bunch
of Kconfig files.  It does a first-cut merge of arch/powerpc/mm,
arch/powerpc/lib and arch/powerpc/platforms/powermac.  This is enough
to build a 32-bit powermac kernel with ARCH=powerpc.

For now we are getting some unmerged files from arch/ppc/kernel and
arch/ppc/syslib, or arch/ppc64/kernel.  This makes some minor changes
to files in those directories and files outside arch/powerpc.

The boot directory is still not merged.  That's going to be interesting.

Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 778 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/head_44x.S b/arch/powerpc/kernel/head_44x.S
new file mode 100644
index 000000000000..599245b0407e
--- /dev/null
+++ b/arch/powerpc/kernel/head_44x.S
@@ -0,0 +1,778 @@
+/*
+ * arch/ppc/kernel/head_44x.S
+ *
+ * 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 2002-2005 MontaVista Software, Inc.
+ *      PowerPC 44x support, Matt Porter <mporter@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/config.h>
+#include <asm/processor.h>
+#include <asm/page.h>
+#include <asm/mmu.h>
+#include <asm/pgtable.h>
+#include <asm/ibm4xx.h>
+#include <asm/ibm44x.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
+ *
+ */
+        .text
+_GLOBAL(_stext)
+_GLOBAL(_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 */
+
+/*
+ * Set up the initial MMU state
+ *
+ * We are still executing code at the virtual address
+ * mappings set by the firmware for the base of RAM.
+ *
+ * We first invalidate all TLB entries but the one
+ * we are running from.  We then load the KERNELBASE
+ * mappings so we can begin to use kernel addresses
+ * natively and so the interrupt vector locations are
+ * permanently pinned (necessary since Book E
+ * implementations always have translation enabled).
+ *
+ * TODO: Use the known TLB entry we are running from to
+ *       determine which physical region we are located
+ *       in.  This can be used to determine where in RAM
+ *       (on a shared CPU system) or PCI memory space
+ *       (on a DRAMless system) we are located.
+ *       For now, we assume a perfect world which means
+ *       we are located at the base of DRAM (physical 0).
+ */
+
+/*
+ * Search TLB for entry that we are currently using.
+ * Invalidate all entries but the one we are using.
+ */
+        /* Load our current PID->MMUCR TID and MSR IS->MMUCR STS */
+        mfspr   r3,SPRN_PID                     /* Get PID */
+        mfmsr   r4                              /* Get MSR */
+        andi.   r4,r4,MSR_IS@l                  /* TS=1? */
+        beq     wmmucr                          /* If not, leave STS=0 */
+        oris    r3,r3,PPC44x_MMUCR_STS@h        /* Set STS=1 */
+wmmucr: mtspr   SPRN_MMUCR,r3                   /* Put MMUCR */
+        sync
+
+        bl      invstr                          /* Find our address */
+invstr: mflr    r5                              /* Make it accessible */
+        tlbsx   r23,0,r5                        /* Find entry we are in */
+        li      r4,0                            /* Start at TLB entry 0 */
+        li      r3,0                            /* Set PAGEID inval value */
+1:      cmpw    r23,r4                          /* Is this our entry? */
+        beq     skpinv                          /* If so, skip the inval */
+        tlbwe   r3,r4,PPC44x_TLB_PAGEID         /* If not, inval the entry */
+skpinv: addi    r4,r4,1                         /* Increment */
+        cmpwi   r4,64                           /* Are we done? */
+        bne     1b                              /* If not, repeat */
+        isync                                   /* If so, context change */
+
+/*
+ * Configure and load pinned entry into TLB slot 63.
+ */
+
+        lis     r3,KERNELBASE@h         /* Load the kernel virtual address */
+        ori     r3,r3,KERNELBASE@l
+
+        /* Kernel is at the base of RAM */
+        li r4, 0                        /* Load the kernel physical address */
+
+        /* Load the kernel PID = 0 */
+        li      r0,0
+        mtspr   SPRN_PID,r0
+        sync
+
+        /* Initialize MMUCR */
+        li      r5,0
+        mtspr   SPRN_MMUCR,r5
+        sync
+
+        /* pageid fields */
+        clrrwi  r3,r3,10                /* Mask off the effective page number */
+        ori     r3,r3,PPC44x_TLB_VALID | PPC44x_TLB_256M
+
+        /* xlat fields */
+        clrrwi  r4,r4,10                /* Mask off the real page number */
+                                        /* ERPN is 0 for first 4GB page */
+
+        /* attrib fields */
+        /* Added guarded bit to protect against speculative loads/stores */
+        li      r5,0
+        ori     r5,r5,(PPC44x_TLB_SW | PPC44x_TLB_SR | PPC44x_TLB_SX | PPC44x_TLB_G)
+
+        li      r0,63                    /* TLB slot 63 */
+
+        tlbwe   r3,r0,PPC44x_TLB_PAGEID /* Load the pageid fields */
+        tlbwe   r4,r0,PPC44x_TLB_XLAT   /* Load the translation fields */
+        tlbwe   r5,r0,PPC44x_TLB_ATTRIB /* Load the attrib/access fields */
+
+        /* Force context change */
+        mfmsr   r0
+        mtspr   SPRN_SRR1, r0
+        lis     r0,3f@h
+        ori     r0,r0,3f@l
+        mtspr   SPRN_SRR0,r0
+        sync
+        rfi
+
+        /* If necessary, invalidate original entry we used */
+3:      cmpwi   r23,63
+        beq     4f
+        li      r6,0
+        tlbwe   r6,r23,PPC44x_TLB_PAGEID
+        isync
+
+4:
+#ifdef CONFIG_SERIAL_TEXT_DEBUG
+        /*
+         * Add temporary UART mapping for early debug.
+         * We can map UART registers wherever we want as long as they don't
+         * interfere with other system mappings (e.g. with pinned entries).
+         * For an example of how we handle this - see ocotea.h.       --ebs
+         */
+        /* pageid fields */
+        lis     r3,UART0_IO_BASE@h
+        ori     r3,r3,PPC44x_TLB_VALID | PPC44x_TLB_4K
+
+        /* xlat fields */
+        lis     r4,UART0_PHYS_IO_BASE@h         /* RPN depends on SoC */
+#ifndef CONFIG_440EP
+        ori     r4,r4,0x0001            /* ERPN is 1 for second 4GB page */
+#endif
+
+        /* attrib fields */
+        li      r5,0
+        ori     r5,r5,(PPC44x_TLB_SW | PPC44x_TLB_SR | PPC44x_TLB_I | PPC44x_TLB_G)
+
+        li      r0,0                    /* TLB slot 0 */
+
+        tlbwe   r3,r0,PPC44x_TLB_PAGEID /* Load the pageid fields */
+        tlbwe   r4,r0,PPC44x_TLB_XLAT   /* Load the translation fields */
+        tlbwe   r5,r0,PPC44x_TLB_ATTRIB /* Load the attrib/access fields */
+
+        /* Force context change */
+        isync
+#endif /* CONFIG_SERIAL_TEXT_DEBUG */
+
+        /* 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);
+
+        /* Establish the interrupt vector base */
+        lis     r4,interrupt_base@h     /* IVPR only uses the high 16-bits */
+        mtspr   SPRN_IVPR,r4
+
+#ifdef CONFIG_440EP
+        /* Clear DAPUIB flag in CCR0 (enable APU between CPU and FPU) */
+        mfspr   r2,SPRN_CCR0
+        lis     r3,0xffef
+        ori     r3,r3,0xffff
+        and     r2,r2,r3
+        mtspr   SPRN_CCR0,r2
+        isync
+#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
+
+/*
+ * 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 */
+
+/*
+ * 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, UnknownException)
+
+        /* Machine Check Interrupt */
+#ifdef CONFIG_440A
+        MCHECK_EXCEPTION(0x0200, MachineCheck, MachineCheckException)
+#else
+        CRITICAL_EXCEPTION(0x0200, MachineCheck, MachineCheckException)
+#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, TASK_SIZE@h
+        cmplw   r10, r11
+        blt+    3f
+        lis     r11, swapper_pg_dir@h
+        ori     r11, r11, swapper_pg_dir@l
+
+        mfspr   r12,SPRN_MMUCR
+        rlwinm  r12,r12,0,0,23          /* Clear TID */
+
+        b       4f
+
+        /* Get the PGD for the current thread */
+3:
+        mfspr   r11,SPRN_SPRG3
+        lwz     r11,PGDIR(r11)
+
+        /* Load PID into MMUCR TID */
+        mfspr   r12,SPRN_MMUCR          /* Get MMUCR */
+        mfspr   r13,SPRN_PID            /* Get PID */
+        rlwimi  r12,r13,0,24,31         /* Set TID */
+
+4:
+        mtspr   SPRN_MMUCR,r12
+
+        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 */
+
+        andi.   r13, r11, _PAGE_RW      /* Is it writeable? */
+        beq     2f                      /* Bail if not */
+
+        /* Update 'changed'.
+        */
+        ori     r11, r11, _PAGE_DIRTY|_PAGE_ACCESSED|_PAGE_HWWRITE
+        stw     r11, 4(r12)             /* Update Linux page table */
+
+        li      r13, PPC44x_TLB_SR@l    /* Set SR */
+        rlwimi  r13, r11, 29, 29, 29    /* SX = _PAGE_HWEXEC */
+        rlwimi  r13, r11, 0, 30, 30     /* SW = _PAGE_RW */
+        rlwimi  r13, r11, 29, 28, 28    /* UR = _PAGE_USER */
+        rlwimi  r12, r11, 31, 26, 26    /* (_PAGE_USER>>1)->r12 */
+        rlwimi  r12, r11, 29, 30, 30    /* (_PAGE_USER>>3)->r12 */
+        and     r12, r12, r11           /* HWEXEC/RW & USER */
+        rlwimi  r13, r12, 0, 26, 26     /* UX = HWEXEC & USER */
+        rlwimi  r13, r12, 3, 27, 27     /* UW = RW & USER */
+
+        rlwimi  r11,r13,0,26,31         /* Insert static perms */
+
+        rlwinm  r11,r11,0,20,15         /* Clear U0-U3 */
+
+        /* find the TLB index that caused the fault.  It has to be here. */
+        tlbsx   r10, 0, r10
+
+        tlbwe   r11, r10, PPC44x_TLB_ATTRIB     /* Write ATTRIB */
+
+        /* 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
+        EXCEPTION(0x2010, FloatingPointUnavailable, UnknownException, EXC_XFER_EE)
+#endif
+
+        /* System Call Interrupt */
+        START_EXCEPTION(SystemCall)
+        NORMAL_EXCEPTION_PROLOG
+        EXC_XFER_EE_LITE(0x0c00, DoSyscall)
+
+        /* Auxillary Processor Unavailable Interrupt */
+        EXCEPTION(0x2020, AuxillaryProcessorUnavailable, UnknownException, EXC_XFER_EE)
+
+        /* Decrementer Interrupt */
+        DECREMENTER_EXCEPTION
+
+        /* Fixed Internal Timer Interrupt */
+        /* TODO: Add FIT support */
+        EXCEPTION(0x1010, FixedIntervalTimer, UnknownException, EXC_XFER_EE)
+
+        /* Watchdog Timer Interrupt */
+        /* TODO: Add watchdog support */
+#ifdef CONFIG_BOOKE_WDT
+        CRITICAL_EXCEPTION(0x1020, WatchdogTimer, WatchdogException)
+#else
+        CRITICAL_EXCEPTION(0x1020, WatchdogTimer, UnknownException)
+#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, TASK_SIZE@h
+        cmplw   r10, r11
+        blt+    3f
+        lis     r11, swapper_pg_dir@h
+        ori     r11, r11, swapper_pg_dir@l
+
+        mfspr   r12,SPRN_MMUCR
+        rlwinm  r12,r12,0,0,23          /* Clear TID */
+
+        b       4f
+
+        /* Get the PGD for the current thread */
+3:
+        mfspr   r11,SPRN_SPRG3
+        lwz     r11,PGDIR(r11)
+
+        /* Load PID into MMUCR TID */
+        mfspr   r12,SPRN_MMUCR
+        mfspr   r13,SPRN_PID            /* Get PID */
+        rlwimi  r12,r13,0,24,31         /* Set TID */
+
+4:
+        mtspr   SPRN_MMUCR,r12
+
+        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 */
+        andi.   r13, r11, _PAGE_PRESENT /* Is the page present? */
+        beq     2f                      /* Bail if not present */
+
+        ori     r11, r11, _PAGE_ACCESSED
+        stw     r11, 4(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, TASK_SIZE@h
+        cmplw   r10, r11
+        blt+    3f
+        lis     r11, swapper_pg_dir@h
+        ori     r11, r11, swapper_pg_dir@l
+
+        mfspr   r12,SPRN_MMUCR
+        rlwinm  r12,r12,0,0,23          /* Clear TID */
+
+        b       4f
+
+        /* Get the PGD for the current thread */
+3:
+        mfspr   r11,SPRN_SPRG3
+        lwz     r11,PGDIR(r11)
+
+        /* Load PID into MMUCR TID */
+        mfspr   r12,SPRN_MMUCR
+        mfspr   r13,SPRN_PID            /* Get PID */
+        rlwimi  r12,r13,0,24,31         /* Set TID */
+
+4:
+        mtspr   SPRN_MMUCR,r12
+
+        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 */
+        andi.   r13, r11, _PAGE_PRESENT /* Is the page present? */
+        beq     2f                      /* Bail if not present */
+
+        ori     r11, r11, _PAGE_ACCESSED
+        stw     r11, 4(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
+
+        /* 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 */
+        EXC_XFER_EE_LITE(0x0300, handle_page_fault)
+
+/*
+
+ * Both the instruction and data TLB miss get to this
+ * point to load the TLB.
+ *      r10 - EA of fault
+ *      r11 - available to use
+ *      r12 - Pointer to the 64-bit PTE
+ *      r13 - available to use
+ *      MMUCR - loaded with proper value when we get here
+ *      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).
+         * If shared is set, we cause a zero PID->TID load.
+         * Many of these bits are software only.  Bits we don't set
+         * here we (properly should) assume have the appropriate value.
+         */
+
+        /* Load the next available TLB index */
+        lis     r13, tlb_44x_index@ha
+        lwz     r13, tlb_44x_index@l(r13)
+        /* Load the TLB high watermark */
+        lis     r11, tlb_44x_hwater@ha
+        lwz     r11, tlb_44x_hwater@l(r11)
+
+        /* Increment, rollover, and store TLB index */
+        addi    r13, r13, 1
+        cmpw    0, r13, r11                     /* reserve entries */
+        ble     7f
+        li      r13, 0
+7:
+        /* Store the next available TLB index */
+        lis     r11, tlb_44x_index@ha
+        stw     r13, tlb_44x_index@l(r11)
+
+        lwz     r11, 0(r12)                     /* Get MS word of PTE */
+        lwz     r12, 4(r12)                     /* Get LS word of PTE */
+        rlwimi  r11, r12, 0, 0 , 19             /* Insert RPN */
+        tlbwe   r11, r13, PPC44x_TLB_XLAT       /* Write XLAT */
+
+        /*
+         * Create PAGEID. This is the faulting address,
+         * page size, and valid flag.
+         */
+        li      r11, PPC44x_TLB_VALID | PPC44x_TLB_4K
+        rlwimi  r10, r11, 0, 20, 31             /* Insert valid and page size */
+        tlbwe   r10, r13, PPC44x_TLB_PAGEID     /* Write PAGEID */
+
+        li      r10, PPC44x_TLB_SR@l            /* Set SR */
+        rlwimi  r10, r12, 0, 30, 30             /* Set SW = _PAGE_RW */
+        rlwimi  r10, r12, 29, 29, 29            /* SX = _PAGE_HWEXEC */
+        rlwimi  r10, r12, 29, 28, 28            /* UR = _PAGE_USER */
+        rlwimi  r11, r12, 31, 26, 26            /* (_PAGE_USER>>1)->r12 */
+        and     r11, r12, r11                   /* HWEXEC & USER */
+        rlwimi  r10, r11, 0, 26, 26             /* UX = HWEXEC & USER */
+
+        rlwimi  r12, r10, 0, 26, 31             /* Insert static perms */
+        rlwinm  r12, r12, 0, 20, 15             /* Clear U0-U3 */
+        tlbwe   r12, r13, PPC44x_TLB_ATTRIB     /* Write ATTRIB */
+
+        /* 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 */
+
+/*
+ * Global functions
+ */
+
+/*
+ * extern void giveup_altivec(struct task_struct *prev)
+ *
+ * The 44x core does not have an AltiVec unit.
+ */
+_GLOBAL(giveup_altivec)
+        blr
+
+/*
+ * extern void giveup_fpu(struct task_struct *prev)
+ *
+ * The 44x core does not 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)
+        mfspr   r13,SPRN_DBCR0
+        oris    r13,r13,DBCR0_RST_SYSTEM@h
+        mtspr   SPRN_DBCR0,r13
+
+_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
+_GLOBAL(sdata)
+_GLOBAL(empty_zero_page)
+        .space  4096
+
+/*
+ * To support >32-bit physical addresses, we use an 8KB pgdir.
+ */
+_GLOBAL(swapper_pg_dir)
+        .space  8192
+
+/* 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
+_GLOBAL(exception_stack_top)
+
+/*
+ * This space gets a copy of optional info passed to us by the bootstrap
+ * which is used to pass parameters into the kernel like root=/dev/sda1, etc.
+ */
+_GLOBAL(cmd_line)
+        .space  512
+
+/*
+ * Room for two PTE pointers, usually the kernel and current user pointers
+ * to their respective root page table.
+ */
+abatron_pteptrs:
+        .space  8
+
+