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
+
+