Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1278 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/head_44x.S b/arch/powerpc/kernel/head_44x.S
new file mode 100644
index 000000000..37e4a7cf0
--- /dev/null
+++ b/arch/powerpc/kernel/head_44x.S
@@ -0,0 +1,1278 @@
+/*
+ * 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/init.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 <asm/ptrace.h>
+#include <asm/synch.h>
+#include <asm/export.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
+ *
+ */
+	__HEAD
+_ENTRY(_stext);
+_ENTRY(_start);
+	/*
+	 * Reserve a word at a fixed location to store the address
+	 * of abatron_pteptrs
+	 */
+	nop
+	mr	r31,r3		/* save device tree ptr */
+	li	r24,0		/* CPU number */
+
+#ifdef CONFIG_RELOCATABLE
+/*
+ * Relocate ourselves to the current runtime address.
+ * This is called only by the Boot CPU.
+ * "relocate" is called with our current runtime virutal
+ * address.
+ * r21 will be loaded with the physical runtime address of _stext
+ */
+	bl	0f				/* Get our runtime address */
+0:	mflr	r21				/* Make it accessible */
+	addis	r21,r21,(_stext - 0b)@ha
+	addi	r21,r21,(_stext - 0b)@l 	/* Get our current runtime base */
+
+	/*
+	 * We have the runtime (virutal) address of our base.
+	 * We calculate our shift of offset from a 256M page.
+	 * We could map the 256M page we belong to at PAGE_OFFSET and
+	 * get going from there.
+	 */
+	lis	r4,KERNELBASE@h
+	ori	r4,r4,KERNELBASE@l
+	rlwinm	r6,r21,0,4,31			/* r6 = PHYS_START % 256M */
+	rlwinm	r5,r4,0,4,31			/* r5 = KERNELBASE % 256M */
+	subf	r3,r5,r6			/* r3 = r6 - r5 */
+	add	r3,r4,r3			/* Required Virutal Address */
+
+	bl	relocate
+#endif
+
+	bl	init_cpu_state
+
+	/*
+	 * 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_SPRG_THREAD,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
+
+#ifdef CONFIG_RELOCATABLE
+	/*
+	 * Relocatable kernel support based on processing of dynamic
+	 * relocation entries.
+	 *
+	 * r25 will contain RPN/ERPN for the start address of memory
+	 * r21 will contain the current offset of _stext
+	 */
+	lis	r3,kernstart_addr@ha
+	la	r3,kernstart_addr@l(r3)
+
+	/*
+	 * Compute the kernstart_addr.
+	 * kernstart_addr => (r6,r8)
+	 * kernstart_addr & ~0xfffffff => (r6,r7)
+	 */
+	rlwinm	r6,r25,0,28,31	/* ERPN. Bits 32-35 of Address */
+	rlwinm	r7,r25,0,0,3	/* RPN - assuming 256 MB page size */
+	rlwinm	r8,r21,0,4,31	/* r8 = (_stext & 0xfffffff) */
+	or	r8,r7,r8	/* Compute the lower 32bit of kernstart_addr */
+
+	/* Store kernstart_addr */
+	stw	r6,0(r3)	/* higher 32bit */
+	stw	r8,4(r3)	/* lower 32bit  */
+
+	/*
+	 * Compute the virt_phys_offset :
+	 * virt_phys_offset = stext.run - kernstart_addr
+	 *
+	 * stext.run = (KERNELBASE & ~0xfffffff) + (kernstart_addr & 0xfffffff)
+	 * When we relocate, we have :
+	 *
+	 *	(kernstart_addr & 0xfffffff) = (stext.run & 0xfffffff)
+	 *
+	 * hence:
+	 *  virt_phys_offset = (KERNELBASE & ~0xfffffff) - (kernstart_addr & ~0xfffffff)
+	 *
+	 */
+
+	/* KERNELBASE&~0xfffffff => (r4,r5) */
+	li	r4, 0		/* higer 32bit */
+	lis	r5,KERNELBASE@h
+	rlwinm	r5,r5,0,0,3	/* Align to 256M, lower 32bit */
+
+	/*
+	 * 64bit subtraction.
+	 */
+	subfc	r5,r7,r5
+	subfe	r4,r6,r4
+
+	/* Store virt_phys_offset */
+	lis	r3,virt_phys_offset@ha
+	la	r3,virt_phys_offset@l(r3)
+
+	stw	r4,0(r3)
+	stw	r5,4(r3)
+
+#elif defined(CONFIG_DYNAMIC_MEMSTART)
+	/*
+	 * Mapping based, page aligned dynamic kernel loading.
+	 *
+	 * r25 will contain RPN/ERPN for the start address of memory
+	 *
+	 * Add the difference between KERNELBASE and PAGE_OFFSET to the
+	 * start of physical memory to get kernstart_addr.
+	 */
+	lis	r3,kernstart_addr@ha
+	la	r3,kernstart_addr@l(r3)
+
+	lis	r4,KERNELBASE@h
+	ori	r4,r4,KERNELBASE@l
+	lis	r5,PAGE_OFFSET@h
+	ori	r5,r5,PAGE_OFFSET@l
+	subf	r4,r5,r4
+
+	rlwinm	r6,r25,0,28,31	/* ERPN */
+	rlwinm	r7,r25,0,0,3	/* RPN - assuming 256 MB page size */
+	add	r7,r7,r4
+
+	stw	r6,0(r3)
+	stw	r7,4(r3)
+#endif
+
+/*
+ * Decide what sort of machine this is and initialize the MMU.
+ */
+	li	r3,0
+	mr	r4,r31
+	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)
+
+	/* Clear the Machine Check Syndrome Register */
+	li	r0,0
+	mtspr	SPRN_MCSR,r0
+
+	/* 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, CRITICAL, CriticalInput, unknown_exception)
+
+	/* Machine Check Interrupt */
+	CRITICAL_EXCEPTION(0x0200, MACHINE_CHECK, MachineCheck, \
+			   machine_check_exception)
+	MCHECK_EXCEPTION(0x0210, MachineCheckA, machine_check_exception)
+
+	/* Data Storage Interrupt */
+	DATA_STORAGE_EXCEPTION
+
+		/* Instruction Storage Interrupt */
+	INSTRUCTION_STORAGE_EXCEPTION
+
+	/* External Input Interrupt */
+	EXCEPTION(0x0500, BOOKE_INTERRUPT_EXTERNAL, 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, BOOKE_INTERRUPT_FP_UNAVAIL, \
+		  FloatingPointUnavailable, unknown_exception, EXC_XFER_EE)
+#endif
+	/* System Call Interrupt */
+	START_EXCEPTION(SystemCall)
+	NORMAL_EXCEPTION_PROLOG(BOOKE_INTERRUPT_SYSCALL)
+	EXC_XFER_EE_LITE(0x0c00, DoSyscall)
+
+	/* Auxiliary Processor Unavailable Interrupt */
+	EXCEPTION(0x2020, BOOKE_INTERRUPT_AP_UNAVAIL, \
+		  AuxillaryProcessorUnavailable, unknown_exception, EXC_XFER_EE)
+
+	/* Decrementer Interrupt */
+	DECREMENTER_EXCEPTION
+
+	/* Fixed Internal Timer Interrupt */
+	/* TODO: Add FIT support */
+	EXCEPTION(0x1010, BOOKE_INTERRUPT_FIT, FixedIntervalTimer, \
+		  unknown_exception, EXC_XFER_EE)
+
+	/* Watchdog Timer Interrupt */
+	/* TODO: Add watchdog support */
+#ifdef CONFIG_BOOKE_WDT
+	CRITICAL_EXCEPTION(0x1020, WATCHDOG, WatchdogTimer, WatchdogException)
+#else
+	CRITICAL_EXCEPTION(0x1020, WATCHDOG, WatchdogTimer, unknown_exception)
+#endif
+
+	/* Data TLB Error Interrupt */
+	START_EXCEPTION(DataTLBError44x)
+	mtspr	SPRN_SPRG_WSCRATCH0, r10		/* Save some working registers */
+	mtspr	SPRN_SPRG_WSCRATCH1, r11
+	mtspr	SPRN_SPRG_WSCRATCH2, r12
+	mtspr	SPRN_SPRG_WSCRATCH3, r13
+	mfcr	r11
+	mtspr	SPRN_SPRG_WSCRATCH4, 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	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_SPRG_THREAD
+	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
+
+	/* Mask of required permission bits. Note that while we
+	 * do copy ESR:ST to _PAGE_RW position as trying to write
+	 * to an RO page is pretty common, we don't do it with
+	 * _PAGE_DIRTY. We could do it, but it's a fairly rare
+	 * event so I'd rather take the overhead when it happens
+	 * rather than adding an instruction here. We should measure
+	 * whether the whole thing is worth it in the first place
+	 * as we could avoid loading SPRN_ESR completely in the first
+	 * place...
+	 *
+	 * TODO: Is it worth doing that mfspr & rlwimi in the first
+	 *       place or can we save a couple of instructions here ?
+	 */
+	mfspr	r12,SPRN_ESR
+	li	r13,_PAGE_PRESENT|_PAGE_ACCESSED
+	rlwimi	r13,r12,10,30,30
+
+	/* Load the PTE */
+	/* Compute pgdir/pmd offset */
+	rlwinm  r12, r10, PPC44x_PGD_OFF_SHIFT, PPC44x_PGD_OFF_MASK_BIT, 29
+	lwzx	r11, r12, r11		/* Get pgd/pmd entry */
+	rlwinm.	r12, r11, 0, 0, 20	/* Extract pt base address */
+	beq	2f			/* Bail if no table */
+
+	/* Compute pte address */
+	rlwimi  r12, r10, PPC44x_PTE_ADD_SHIFT, PPC44x_PTE_ADD_MASK_BIT, 28
+	lwz	r11, 0(r12)		/* Get high word of pte entry */
+	lwz	r12, 4(r12)		/* Get low word of pte entry */
+
+	lis	r10,tlb_44x_index@ha
+
+	andc.	r13,r13,r12		/* Check permission */
+
+	/* Load the next available TLB index */
+	lwz	r13,tlb_44x_index@l(r10)
+
+	bne	2f			/* Bail if permission mismach */
+
+	/* Increment, rollover, and store TLB index */
+	addi	r13,r13,1
+
+	/* Compare with watermark (instruction gets patched) */
+	.globl tlb_44x_patch_hwater_D
+tlb_44x_patch_hwater_D:
+	cmpwi	0,r13,1			/* reserve entries */
+	ble	5f
+	li	r13,0
+5:
+	/* Store the next available TLB index */
+	stw	r13,tlb_44x_index@l(r10)
+
+	/* Re-load the faulting address */
+	mfspr	r10,SPRN_DEAR
+
+	 /* Jump to common tlb load */
+	b	finish_tlb_load_44x
+
+2:
+	/* The bailout.  Restore registers to pre-exception conditions
+	 * and call the heavyweights to help us out.
+	 */
+	mfspr	r11, SPRN_SPRG_RSCRATCH4
+	mtcr	r11
+	mfspr	r13, SPRN_SPRG_RSCRATCH3
+	mfspr	r12, SPRN_SPRG_RSCRATCH2
+	mfspr	r11, SPRN_SPRG_RSCRATCH1
+	mfspr	r10, SPRN_SPRG_RSCRATCH0
+	b	DataStorage
+
+	/* 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(InstructionTLBError44x)
+	mtspr	SPRN_SPRG_WSCRATCH0, r10 /* Save some working registers */
+	mtspr	SPRN_SPRG_WSCRATCH1, r11
+	mtspr	SPRN_SPRG_WSCRATCH2, r12
+	mtspr	SPRN_SPRG_WSCRATCH3, r13
+	mfcr	r11
+	mtspr	SPRN_SPRG_WSCRATCH4, 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	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_SPRG_THREAD
+	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
+
+	/* Make up the required permissions */
+	li	r13,_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_EXEC
+
+	/* Compute pgdir/pmd offset */
+	rlwinm 	r12, r10, PPC44x_PGD_OFF_SHIFT, PPC44x_PGD_OFF_MASK_BIT, 29
+	lwzx	r11, r12, r11		/* Get pgd/pmd entry */
+	rlwinm.	r12, r11, 0, 0, 20	/* Extract pt base address */
+	beq	2f			/* Bail if no table */
+
+	/* Compute pte address */
+	rlwimi	r12, r10, PPC44x_PTE_ADD_SHIFT, PPC44x_PTE_ADD_MASK_BIT, 28
+	lwz	r11, 0(r12)		/* Get high word of pte entry */
+	lwz	r12, 4(r12)		/* Get low word of pte entry */
+
+	lis	r10,tlb_44x_index@ha
+
+	andc.	r13,r13,r12		/* Check permission */
+
+	/* Load the next available TLB index */
+	lwz	r13,tlb_44x_index@l(r10)
+
+	bne	2f			/* Bail if permission mismach */
+
+	/* Increment, rollover, and store TLB index */
+	addi	r13,r13,1
+
+	/* Compare with watermark (instruction gets patched) */
+	.globl tlb_44x_patch_hwater_I
+tlb_44x_patch_hwater_I:
+	cmpwi	0,r13,1			/* reserve entries */
+	ble	5f
+	li	r13,0
+5:
+	/* Store the next available TLB index */
+	stw	r13,tlb_44x_index@l(r10)
+
+	/* Re-load the faulting address */
+	mfspr	r10,SPRN_SRR0
+
+	/* Jump to common TLB load point */
+	b	finish_tlb_load_44x
+
+2:
+	/* The bailout.  Restore registers to pre-exception conditions
+	 * and call the heavyweights to help us out.
+	 */
+	mfspr	r11, SPRN_SPRG_RSCRATCH4
+	mtcr	r11
+	mfspr	r13, SPRN_SPRG_RSCRATCH3
+	mfspr	r12, SPRN_SPRG_RSCRATCH2
+	mfspr	r11, SPRN_SPRG_RSCRATCH1
+	mfspr	r10, SPRN_SPRG_RSCRATCH0
+	b	InstructionStorage
+
+/*
+ * Both the instruction and data TLB miss get to this
+ * point to load the TLB.
+ * 	r10 - EA of fault
+ * 	r11 - PTE high word value
+ *	r12 - PTE low word value
+ *	r13 - TLB index
+ *	MMUCR - loaded with proper value when we get here
+ *	Upon exit, we reload everything and RFI.
+ */
+finish_tlb_load_44x:
+	/* Combine RPN & ERPN an write WS 0 */
+	rlwimi	r11,r12,0,0,31-PAGE_SHIFT
+	tlbwe	r11,r13,PPC44x_TLB_XLAT
+
+	/*
+	 * Create WS1. This is the faulting address (EPN),
+	 * page size, and valid flag.
+	 */
+	li	r11,PPC44x_TLB_VALID | PPC44x_TLBE_SIZE
+	/* Insert valid and page size */
+	rlwimi	r10,r11,0,PPC44x_PTE_ADD_MASK_BIT,31
+	tlbwe	r10,r13,PPC44x_TLB_PAGEID	/* Write PAGEID */
+
+	/* And WS 2 */
+	li	r10,0xf85			/* Mask to apply from PTE */
+	rlwimi	r10,r12,29,30,30		/* DIRTY -> SW position */
+	and	r11,r12,r10			/* Mask PTE bits to keep */
+	andi.	r10,r12,_PAGE_USER		/* User page ? */
+	beq	1f				/* nope, leave U bits empty */
+	rlwimi	r11,r11,3,26,28			/* yes, copy S bits to U */
+1:	tlbwe	r11,r13,PPC44x_TLB_ATTRIB	/* Write ATTRIB */
+
+	/* Done...restore registers and get out of here.
+	*/
+	mfspr	r11, SPRN_SPRG_RSCRATCH4
+	mtcr	r11
+	mfspr	r13, SPRN_SPRG_RSCRATCH3
+	mfspr	r12, SPRN_SPRG_RSCRATCH2
+	mfspr	r11, SPRN_SPRG_RSCRATCH1
+	mfspr	r10, SPRN_SPRG_RSCRATCH0
+	rfi					/* Force context change */
+
+/* TLB error interrupts for 476
+ */
+#ifdef CONFIG_PPC_47x
+	START_EXCEPTION(DataTLBError47x)
+	mtspr	SPRN_SPRG_WSCRATCH0,r10	/* Save some working registers */
+	mtspr	SPRN_SPRG_WSCRATCH1,r11
+	mtspr	SPRN_SPRG_WSCRATCH2,r12
+	mtspr	SPRN_SPRG_WSCRATCH3,r13
+	mfcr	r11
+	mtspr	SPRN_SPRG_WSCRATCH4,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	cr0,r10,r11
+	blt+	3f
+	lis	r11,swapper_pg_dir@h
+	ori	r11,r11, swapper_pg_dir@l
+	li	r12,0			/* MMUCR = 0 */
+	b	4f
+
+	/* Get the PGD for the current thread and setup MMUCR */
+3:	mfspr	r11,SPRN_SPRG3
+	lwz	r11,PGDIR(r11)
+	mfspr   r12,SPRN_PID		/* Get PID */
+4:	mtspr	SPRN_MMUCR,r12		/* Set MMUCR */
+
+	/* Mask of required permission bits. Note that while we
+	 * do copy ESR:ST to _PAGE_RW position as trying to write
+	 * to an RO page is pretty common, we don't do it with
+	 * _PAGE_DIRTY. We could do it, but it's a fairly rare
+	 * event so I'd rather take the overhead when it happens
+	 * rather than adding an instruction here. We should measure
+	 * whether the whole thing is worth it in the first place
+	 * as we could avoid loading SPRN_ESR completely in the first
+	 * place...
+	 *
+	 * TODO: Is it worth doing that mfspr & rlwimi in the first
+	 *       place or can we save a couple of instructions here ?
+	 */
+	mfspr	r12,SPRN_ESR
+	li	r13,_PAGE_PRESENT|_PAGE_ACCESSED
+	rlwimi	r13,r12,10,30,30
+
+	/* Load the PTE */
+	/* Compute pgdir/pmd offset */
+	rlwinm  r12,r10,PPC44x_PGD_OFF_SHIFT,PPC44x_PGD_OFF_MASK_BIT,29
+	lwzx	r11,r12,r11		/* Get pgd/pmd entry */
+
+	/* Word 0 is EPN,V,TS,DSIZ */
+	li	r12,PPC47x_TLB0_VALID | PPC47x_TLBE_SIZE
+	rlwimi	r10,r12,0,32-PAGE_SHIFT,31	/* Insert valid and page size*/
+	li	r12,0
+	tlbwe	r10,r12,0
+
+	/* XXX can we do better ? Need to make sure tlbwe has established
+	 * latch V bit in MMUCR0 before the PTE is loaded further down */
+#ifdef CONFIG_SMP
+	isync
+#endif
+
+	rlwinm.	r12,r11,0,0,20		/* Extract pt base address */
+	/* Compute pte address */
+	rlwimi  r12,r10,PPC44x_PTE_ADD_SHIFT,PPC44x_PTE_ADD_MASK_BIT,28
+	beq	2f			/* Bail if no table */
+	lwz	r11,0(r12)		/* Get high word of pte entry */
+
+	/* XXX can we do better ? maybe insert a known 0 bit from r11 into the
+	 * bottom of r12 to create a data dependency... We can also use r10
+	 * as destination nowadays
+	 */
+#ifdef CONFIG_SMP
+	lwsync
+#endif
+	lwz	r12,4(r12)		/* Get low word of pte entry */
+
+	andc.	r13,r13,r12		/* Check permission */
+
+	 /* Jump to common tlb load */
+	beq	finish_tlb_load_47x
+
+2:	/* The bailout.  Restore registers to pre-exception conditions
+	 * and call the heavyweights to help us out.
+	 */
+	mfspr	r11,SPRN_SPRG_RSCRATCH4
+	mtcr	r11
+	mfspr	r13,SPRN_SPRG_RSCRATCH3
+	mfspr	r12,SPRN_SPRG_RSCRATCH2
+	mfspr	r11,SPRN_SPRG_RSCRATCH1
+	mfspr	r10,SPRN_SPRG_RSCRATCH0
+	b	DataStorage
+
+	/* 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(InstructionTLBError47x)
+	mtspr	SPRN_SPRG_WSCRATCH0,r10	/* Save some working registers */
+	mtspr	SPRN_SPRG_WSCRATCH1,r11
+	mtspr	SPRN_SPRG_WSCRATCH2,r12
+	mtspr	SPRN_SPRG_WSCRATCH3,r13
+	mfcr	r11
+	mtspr	SPRN_SPRG_WSCRATCH4,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	cr0,r10,r11
+	blt+	3f
+	lis	r11,swapper_pg_dir@h
+	ori	r11,r11, swapper_pg_dir@l
+	li	r12,0			/* MMUCR = 0 */
+	b	4f
+
+	/* Get the PGD for the current thread and setup MMUCR */
+3:	mfspr	r11,SPRN_SPRG_THREAD
+	lwz	r11,PGDIR(r11)
+	mfspr   r12,SPRN_PID		/* Get PID */
+4:	mtspr	SPRN_MMUCR,r12		/* Set MMUCR */
+
+	/* Make up the required permissions */
+	li	r13,_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_EXEC
+
+	/* Load PTE */
+	/* Compute pgdir/pmd offset */
+	rlwinm  r12,r10,PPC44x_PGD_OFF_SHIFT,PPC44x_PGD_OFF_MASK_BIT,29
+	lwzx	r11,r12,r11		/* Get pgd/pmd entry */
+
+	/* Word 0 is EPN,V,TS,DSIZ */
+	li	r12,PPC47x_TLB0_VALID | PPC47x_TLBE_SIZE
+	rlwimi	r10,r12,0,32-PAGE_SHIFT,31	/* Insert valid and page size*/
+	li	r12,0
+	tlbwe	r10,r12,0
+
+	/* XXX can we do better ? Need to make sure tlbwe has established
+	 * latch V bit in MMUCR0 before the PTE is loaded further down */
+#ifdef CONFIG_SMP
+	isync
+#endif
+
+	rlwinm.	r12,r11,0,0,20		/* Extract pt base address */
+	/* Compute pte address */
+	rlwimi  r12,r10,PPC44x_PTE_ADD_SHIFT,PPC44x_PTE_ADD_MASK_BIT,28
+	beq	2f			/* Bail if no table */
+
+	lwz	r11,0(r12)		/* Get high word of pte entry */
+	/* XXX can we do better ? maybe insert a known 0 bit from r11 into the
+	 * bottom of r12 to create a data dependency... We can also use r10
+	 * as destination nowadays
+	 */
+#ifdef CONFIG_SMP
+	lwsync
+#endif
+	lwz	r12,4(r12)		/* Get low word of pte entry */
+
+	andc.	r13,r13,r12		/* Check permission */
+
+	/* Jump to common TLB load point */
+	beq	finish_tlb_load_47x
+
+2:	/* The bailout.  Restore registers to pre-exception conditions
+	 * and call the heavyweights to help us out.
+	 */
+	mfspr	r11, SPRN_SPRG_RSCRATCH4
+	mtcr	r11
+	mfspr	r13, SPRN_SPRG_RSCRATCH3
+	mfspr	r12, SPRN_SPRG_RSCRATCH2
+	mfspr	r11, SPRN_SPRG_RSCRATCH1
+	mfspr	r10, SPRN_SPRG_RSCRATCH0
+	b	InstructionStorage
+
+/*
+ * Both the instruction and data TLB miss get to this
+ * point to load the TLB.
+ * 	r10 - free to use
+ * 	r11 - PTE high word value
+ *	r12 - PTE low word value
+ *      r13 - free to use
+ *	MMUCR - loaded with proper value when we get here
+ *	Upon exit, we reload everything and RFI.
+ */
+finish_tlb_load_47x:
+	/* Combine RPN & ERPN an write WS 1 */
+	rlwimi	r11,r12,0,0,31-PAGE_SHIFT
+	tlbwe	r11,r13,1
+
+	/* And make up word 2 */
+	li	r10,0xf85			/* Mask to apply from PTE */
+	rlwimi	r10,r12,29,30,30		/* DIRTY -> SW position */
+	and	r11,r12,r10			/* Mask PTE bits to keep */
+	andi.	r10,r12,_PAGE_USER		/* User page ? */
+	beq	1f				/* nope, leave U bits empty */
+	rlwimi	r11,r11,3,26,28			/* yes, copy S bits to U */
+1:	tlbwe	r11,r13,2
+
+	/* Done...restore registers and get out of here.
+	*/
+	mfspr	r11, SPRN_SPRG_RSCRATCH4
+	mtcr	r11
+	mfspr	r13, SPRN_SPRG_RSCRATCH3
+	mfspr	r12, SPRN_SPRG_RSCRATCH2
+	mfspr	r11, SPRN_SPRG_RSCRATCH1
+	mfspr	r10, SPRN_SPRG_RSCRATCH0
+	rfi
+
+#endif /* CONFIG_PPC_47x */
+
+	/* Debug Interrupt */
+	/*
+	 * This statement needs to exist at the end of the IVPR
+	 * definition just in case you end up taking a debug
+	 * exception within another exception.
+	 */
+	DEBUG_CRIT_EXCEPTION
+
+interrupt_end:
+
+/*
+ * Global functions
+ */
+
+/*
+ * Adjust the machine check IVOR on 440A cores
+ */
+_GLOBAL(__fixup_440A_mcheck)
+	li	r3,MachineCheckA@l
+	mtspr	SPRN_IVOR1,r3
+	sync
+	blr
+
+_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
+
+/*
+ * Init CPU state. This is called at boot time or for secondary CPUs
+ * to setup initial TLB entries, setup IVORs, etc...
+ *
+ */
+_GLOBAL(init_cpu_state)
+	mflr	r22
+#ifdef CONFIG_PPC_47x
+	/* We use the PVR to differentiate 44x cores from 476 */
+	mfspr	r3,SPRN_PVR
+	srwi	r3,r3,16
+	cmplwi	cr0,r3,PVR_476FPE@h
+	beq	head_start_47x
+	cmplwi	cr0,r3,PVR_476@h
+	beq	head_start_47x
+	cmplwi	cr0,r3,PVR_476_ISS@h
+	beq	head_start_47x
+#endif /* CONFIG_PPC_47x */
+
+/*
+ * In case the firmware didn't do it, we apply some workarounds
+ * that are good for all 440 core variants here
+ */
+	mfspr	r3,SPRN_CCR0
+	rlwinm	r3,r3,0,0,27	/* disable icache prefetch */
+	isync
+	mtspr	SPRN_CCR0,r3
+	isync
+	sync
+
+/*
+ * Set up the initial MMU state for 44x
+ *
+ * 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.
+ */
+#ifdef CONFIG_NONSTATIC_KERNEL
+	/*
+	 * In case of a NONSTATIC_KERNEL we reuse the TLB XLAT
+	 * entries of the initial mapping set by the boot loader.
+	 * The XLAT entry is stored in r25
+	 */
+
+	/* Read the XLAT entry for our current mapping */
+	tlbre	r25,r23,PPC44x_TLB_XLAT
+
+	lis	r3,KERNELBASE@h
+	ori	r3,r3,KERNELBASE@l
+
+	/* Use our current RPN entry */
+	mr	r4,r25
+#else
+
+	lis	r3,PAGE_OFFSET@h
+	ori	r3,r3,PAGE_OFFSET@l
+
+	/* Kernel is at the base of RAM */
+	li r4, 0			/* Load the kernel physical address */
+#endif
+
+	/* 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_PPC_EARLY_DEBUG_44x
+	/* Add UART mapping for early debug. */
+
+	/* pageid fields */
+	lis	r3,PPC44x_EARLY_DEBUG_VIRTADDR@h
+	ori	r3,r3,PPC44x_TLB_VALID|PPC44x_TLB_TS|PPC44x_TLB_64K
+
+	/* xlat fields */
+	lis	r4,CONFIG_PPC_EARLY_DEBUG_44x_PHYSLOW@h
+	ori	r4,r4,CONFIG_PPC_EARLY_DEBUG_44x_PHYSHIGH
+
+	/* attrib fields */
+	li	r5,(PPC44x_TLB_SW|PPC44x_TLB_SR|PPC44x_TLB_I|PPC44x_TLB_G)
+        li      r0,62                    /* TLB slot 0 */
+
+	tlbwe	r3,r0,PPC44x_TLB_PAGEID
+	tlbwe	r4,r0,PPC44x_TLB_XLAT
+	tlbwe	r5,r0,PPC44x_TLB_ATTRIB
+
+	/* Force context change */
+	isync
+#endif /* CONFIG_PPC_EARLY_DEBUG_44x */
+
+	/* 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, DataTLBError44x);
+	SET_IVOR(14, InstructionTLBError44x);
+	SET_IVOR(15, DebugCrit);
+
+	b	head_start_common
+
+
+#ifdef CONFIG_PPC_47x
+
+#ifdef CONFIG_SMP
+
+/* Entry point for secondary 47x processors */
+_GLOBAL(start_secondary_47x)
+        mr      r24,r3          /* CPU number */
+
+	bl	init_cpu_state
+
+	/* Now we need to bolt the rest of kernel memory which
+	 * is done in C code. We must be careful because our task
+	 * struct or our stack can (and will probably) be out
+	 * of reach of the initial 256M TLB entry, so we use a
+	 * small temporary stack in .bss for that. This works
+	 * because only one CPU at a time can be in this code
+	 */
+	lis	r1,temp_boot_stack@h
+	ori	r1,r1,temp_boot_stack@l
+	addi	r1,r1,1024-STACK_FRAME_OVERHEAD
+	li	r0,0
+	stw	r0,0(r1)
+	bl	mmu_init_secondary
+
+	/* Now we can get our task struct and real stack pointer */
+
+	/* Get current_thread_info and current */
+	lis	r1,secondary_ti@ha
+	lwz	r1,secondary_ti@l(r1)
+	lwz	r2,TI_TASK(r1)
+
+	/* Current stack pointer */
+	addi	r1,r1,THREAD_SIZE-STACK_FRAME_OVERHEAD
+	li	r0,0
+	stw	r0,0(r1)
+
+	/* Kernel stack for exception entry in SPRG3 */
+	addi	r4,r2,THREAD	/* init task's THREAD */
+	mtspr	SPRN_SPRG3,r4
+
+	b	start_secondary
+
+#endif /* CONFIG_SMP */
+
+/*
+ * Set up the initial MMU state for 44x
+ *
+ * We are still executing code at the virtual address
+ * mappings set by the firmware for the base of RAM.
+ */
+
+head_start_47x:
+	/* 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	1f				/* If not, leave STS=0 */
+	oris	r3,r3,PPC47x_MMUCR_STS@h	/* Set STS=1 */
+1:	mtspr	SPRN_MMUCR,r3			/* Put MMUCR */
+	sync
+
+	/* Find the entry we are running from */
+	bl	1f
+1:	mflr	r23
+	tlbsx	r23,0,r23
+	tlbre	r24,r23,0
+	tlbre	r25,r23,1
+	tlbre	r26,r23,2
+
+/*
+ * Cleanup time
+ */
+
+	/* Initialize MMUCR */
+	li	r5,0
+	mtspr	SPRN_MMUCR,r5
+	sync
+
+clear_all_utlb_entries:
+
+	#; Set initial values.
+
+	addis		r3,0,0x8000
+	addi		r4,0,0
+	addi		r5,0,0
+	b		clear_utlb_entry
+
+	#; Align the loop to speed things up.
+
+	.align		6
+
+clear_utlb_entry:
+
+	tlbwe		r4,r3,0
+	tlbwe		r5,r3,1
+	tlbwe		r5,r3,2
+	addis		r3,r3,0x2000
+	cmpwi		r3,0
+	bne		clear_utlb_entry
+	addis		r3,0,0x8000
+	addis		r4,r4,0x100
+	cmpwi		r4,0
+	bne		clear_utlb_entry
+
+	#; Restore original entry.
+
+	oris	r23,r23,0x8000  /* specify the way */
+	tlbwe		r24,r23,0
+	tlbwe		r25,r23,1
+	tlbwe		r26,r23,2
+
+/*
+ * Configure and load pinned entry into TLB for the kernel core
+ */
+
+	lis	r3,PAGE_OFFSET@h
+	ori	r3,r3,PAGE_OFFSET@l
+
+	/* Load the kernel PID = 0 */
+	li	r0,0
+	mtspr	SPRN_PID,r0
+	sync
+
+	/* Word 0 */
+	clrrwi	r3,r3,12		/* Mask off the effective page number */
+	ori	r3,r3,PPC47x_TLB0_VALID | PPC47x_TLB0_256M
+
+	/* Word 1 - use r25.  RPN is the same as the original entry */
+
+	/* Word 2 */
+	li	r5,0
+	ori	r5,r5,PPC47x_TLB2_S_RWX
+#ifdef CONFIG_SMP
+	ori	r5,r5,PPC47x_TLB2_M
+#endif
+
+	/* We write to way 0 and bolted 0 */
+	lis	r0,0x8800
+	tlbwe	r3,r0,0
+	tlbwe	r25,r0,1
+	tlbwe	r5,r0,2
+
+/*
+ * Configure SSPCR, ISPCR and USPCR for now to search everything, we can fix
+ * them up later
+ */
+	LOAD_REG_IMMEDIATE(r3, 0x9abcdef0)
+	mtspr	SPRN_SSPCR,r3
+	mtspr	SPRN_USPCR,r3
+	LOAD_REG_IMMEDIATE(r3, 0x12345670)
+	mtspr	SPRN_ISPCR,r3
+
+	/* Force context change */
+	mfmsr	r0
+	mtspr	SPRN_SRR1, r0
+	lis	r0,3f@h
+	ori	r0,r0,3f@l
+	mtspr	SPRN_SRR0,r0
+	sync
+	rfi
+
+	/* Invalidate original entry we used */
+3:
+	rlwinm	r24,r24,0,21,19 /* clear the "valid" bit */
+	tlbwe	r24,r23,0
+	addi	r24,0,0
+	tlbwe	r24,r23,1
+	tlbwe	r24,r23,2
+	isync                   /* Clear out the shadow TLB entries */
+
+#ifdef CONFIG_PPC_EARLY_DEBUG_44x
+	/* Add UART mapping for early debug. */
+
+	/* Word 0 */
+	lis	r3,PPC44x_EARLY_DEBUG_VIRTADDR@h
+	ori	r3,r3,PPC47x_TLB0_VALID | PPC47x_TLB0_TS | PPC47x_TLB0_1M
+
+	/* Word 1 */
+	lis	r4,CONFIG_PPC_EARLY_DEBUG_44x_PHYSLOW@h
+	ori	r4,r4,CONFIG_PPC_EARLY_DEBUG_44x_PHYSHIGH
+
+	/* Word 2 */
+	li	r5,(PPC47x_TLB2_S_RW | PPC47x_TLB2_IMG)
+
+	/* Bolted in way 0, bolt slot 5, we -hope- we don't hit the same
+	 * congruence class as the kernel, we need to make sure of it at
+	 * some point
+	 */
+        lis	r0,0x8d00
+	tlbwe	r3,r0,0
+	tlbwe	r4,r0,1
+	tlbwe	r5,r0,2
+
+	/* Force context change */
+	isync
+#endif /* CONFIG_PPC_EARLY_DEBUG_44x */
+
+	/* Establish the interrupt vector offsets */
+	SET_IVOR(0,  CriticalInput);
+	SET_IVOR(1,  MachineCheckA);
+	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, DataTLBError47x);
+	SET_IVOR(14, InstructionTLBError47x);
+	SET_IVOR(15, DebugCrit);
+
+	/* We configure icbi to invalidate 128 bytes at a time since the
+	 * current 32-bit kernel code isn't too happy with icache != dcache
+	 * block size. We also disable the BTAC as this can cause errors
+	 * in some circumstances (see IBM Erratum 47).
+	 */
+	mfspr	r3,SPRN_CCR0
+	oris	r3,r3,0x0020
+	ori	r3,r3,0x0040
+	mtspr	SPRN_CCR0,r3
+	isync
+
+#endif /* CONFIG_PPC_47x */
+
+/*
+ * Here we are back to code that is common between 44x and 47x
+ *
+ * We proceed to further kernel initialization and return to the
+ * main kernel entry
+ */
+head_start_common:
+	/* Establish the interrupt vector base */
+	lis	r4,interrupt_base@h	/* IVPR only uses the high 16-bits */
+	mtspr	SPRN_IVPR,r4
+
+	/*
+	 * If the kernel was loaded at a non-zero 256 MB page, we need to
+	 * mask off the most significant 4 bits to get the relative address
+	 * from the start of physical memory
+	 */
+	rlwinm	r22,r22,0,4,31
+	addis	r22,r22,PAGE_OFFSET@h
+	mtlr	r22
+	isync
+	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	PAGE_SHIFT
+	.globl	sdata
+sdata:
+	.globl	empty_zero_page
+empty_zero_page:
+	.space	PAGE_SIZE
+EXPORT_SYMBOL(empty_zero_page)
+
+/*
+ * To support >32-bit physical addresses, we use an 8KB pgdir.
+ */
+	.globl	swapper_pg_dir
+swapper_pg_dir:
+	.space	PGD_TABLE_SIZE
+
+/*
+ * Room for two PTE pointers, usually the kernel and current user pointers
+ * to their respective root page table.
+ */
+abatron_pteptrs:
+	.space	8
+
+#ifdef CONFIG_SMP
+	.align	12
+temp_boot_stack:
+	.space	1024
+#endif /* CONFIG_SMP */