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+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * PowerPC version
+ * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
+ * Rewritten by Cort Dougan (cort@cs.nmt.edu) for PReP
+ * Copyright (C) 1996 Cort Dougan <cort@cs.nmt.edu>
+ * Low-level exception handlers and MMU support
+ * rewritten by Paul Mackerras.
+ * Copyright (C) 1996 Paul Mackerras.
+ * MPC8xx modifications by Dan Malek
+ * Copyright (C) 1997 Dan Malek (dmalek@jlc.net).
+ *
+ * This file contains low-level support and setup for PowerPC 8xx
+ * embedded processors, including trap and interrupt dispatch.
+ */
+
+#include <linux/init.h>
+#include <linux/magic.h>
+#include <linux/pgtable.h>
+#include <linux/sizes.h>
+#include <asm/processor.h>
+#include <asm/page.h>
+#include <asm/mmu.h>
+#include <asm/cache.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/export.h>
+#include <asm/code-patching-asm.h>
+
+#include "head_32.h"
+
+.macro compare_to_kernel_boundary scratch, addr
+#if CONFIG_TASK_SIZE <= 0x80000000 && CONFIG_PAGE_OFFSET >= 0x80000000
+/* By simply checking Address >= 0x80000000, we know if its a kernel address */
+ not. \scratch, \addr
+#else
+ rlwinm \scratch, \addr, 16, 0xfff8
+ cmpli cr0, \scratch, PAGE_OFFSET@h
+#endif
+.endm
+
+/*
+ * We need an ITLB miss handler for kernel addresses if:
+ * - Either we have modules
+ * - Or we have not pinned the first 8M
+ */
+#if defined(CONFIG_MODULES) || !defined(CONFIG_PIN_TLB_TEXT) || \
+ defined(CONFIG_DEBUG_PAGEALLOC)
+#define ITLB_MISS_KERNEL 1
+#endif
+
+/*
+ * Value for the bits that have fixed value in RPN entries.
+ * Also used for tagging DAR for DTLBerror.
+ */
+#define RPN_PATTERN 0x00f0
+
+#define PAGE_SHIFT_512K 19
+#define PAGE_SHIFT_8M 23
+
+ __HEAD
+_ENTRY(_stext);
+_ENTRY(_start);
+
+/* MPC8xx
+ * This port was done on an MBX board with an 860. Right now I only
+ * support an ELF compressed (zImage) boot from EPPC-Bug because the
+ * code there loads up some registers before calling us:
+ * r3: ptr to board info data
+ * r4: initrd_start or if no initrd then 0
+ * r5: initrd_end - unused if r4 is 0
+ * r6: Start of command line string
+ * r7: End of command line string
+ *
+ * I decided to use conditional compilation instead of checking PVR and
+ * adding more processor specific branches around code I don't need.
+ * Since this is an embedded processor, I also appreciate any memory
+ * savings I can get.
+ *
+ * The MPC8xx does not have any BATs, but it supports large page sizes.
+ * We first initialize the MMU to support 8M byte pages, then load one
+ * entry into each of the instruction and data TLBs to map the first
+ * 8M 1:1. I also mapped an additional I/O space 1:1 so we can get to
+ * the "internal" processor registers before MMU_init is called.
+ *
+ * -- Dan
+ */
+ .globl __start
+__start:
+ mr r31,r3 /* save device tree ptr */
+
+ /* We have to turn on the MMU right away so we get cache modes
+ * set correctly.
+ */
+ bl initial_mmu
+
+/* We now have the lower 8 Meg mapped into TLB entries, and the caches
+ * ready to work.
+ */
+
+turn_on_mmu:
+ mfmsr r0
+ ori r0,r0,MSR_DR|MSR_IR
+ mtspr SPRN_SRR1,r0
+ lis r0,start_here@h
+ ori r0,r0,start_here@l
+ mtspr SPRN_SRR0,r0
+ rfi /* enables MMU */
+
+
+#ifdef CONFIG_PERF_EVENTS
+ .align 4
+
+ .globl itlb_miss_counter
+itlb_miss_counter:
+ .space 4
+
+ .globl dtlb_miss_counter
+dtlb_miss_counter:
+ .space 4
+
+ .globl instruction_counter
+instruction_counter:
+ .space 4
+#endif
+
+/* System reset */
+ EXCEPTION(0x100, Reset, system_reset_exception, EXC_XFER_STD)
+
+/* Machine check */
+ . = 0x200
+MachineCheck:
+ EXCEPTION_PROLOG handle_dar_dsisr=1
+ save_dar_dsisr_on_stack r4, r5, r11
+ li r6, RPN_PATTERN
+ mtspr SPRN_DAR, r6 /* Tag DAR, to be used in DTLB Error */
+ addi r3,r1,STACK_FRAME_OVERHEAD
+ EXC_XFER_STD(0x200, machine_check_exception)
+
+/* External interrupt */
+ EXCEPTION(0x500, HardwareInterrupt, do_IRQ, EXC_XFER_LITE)
+
+/* Alignment exception */
+ . = 0x600
+Alignment:
+ EXCEPTION_PROLOG handle_dar_dsisr=1
+ save_dar_dsisr_on_stack r4, r5, r11
+ li r6, RPN_PATTERN
+ mtspr SPRN_DAR, r6 /* Tag DAR, to be used in DTLB Error */
+ addi r3,r1,STACK_FRAME_OVERHEAD
+ b .Lalignment_exception_ool
+
+/* Program check exception */
+ EXCEPTION(0x700, ProgramCheck, program_check_exception, EXC_XFER_STD)
+
+/* Decrementer */
+ EXCEPTION(0x900, Decrementer, timer_interrupt, EXC_XFER_LITE)
+
+ /* With VMAP_STACK there's not enough room for this at 0x600 */
+ . = 0xa00
+.Lalignment_exception_ool:
+ EXC_XFER_STD(0x600, alignment_exception)
+
+/* System call */
+ . = 0xc00
+SystemCall:
+ SYSCALL_ENTRY 0xc00
+
+/* Single step - not used on 601 */
+ EXCEPTION(0xd00, SingleStep, single_step_exception, EXC_XFER_STD)
+
+/* On the MPC8xx, this is a software emulation interrupt. It occurs
+ * for all unimplemented and illegal instructions.
+ */
+ EXCEPTION(0x1000, SoftEmu, emulation_assist_interrupt, EXC_XFER_STD)
+
+ . = 0x1100
+/*
+ * For the MPC8xx, this is a software tablewalk to load the instruction
+ * TLB. The task switch loads the M_TWB register with the pointer to the first
+ * level table.
+ * If we discover there is no second level table (value is zero) or if there
+ * is an invalid pte, we load that into the TLB, which causes another fault
+ * into the TLB Error interrupt where we can handle such problems.
+ * We have to use the MD_xxx registers for the tablewalk because the
+ * equivalent MI_xxx registers only perform the attribute functions.
+ */
+
+#ifdef CONFIG_8xx_CPU15
+#define INVALIDATE_ADJACENT_PAGES_CPU15(addr) \
+ addi addr, addr, PAGE_SIZE; \
+ tlbie addr; \
+ addi addr, addr, -(PAGE_SIZE << 1); \
+ tlbie addr; \
+ addi addr, addr, PAGE_SIZE
+#else
+#define INVALIDATE_ADJACENT_PAGES_CPU15(addr)
+#endif
+
+InstructionTLBMiss:
+ mtspr SPRN_SPRG_SCRATCH0, r10
+ mtspr SPRN_SPRG_SCRATCH1, r11
+
+ /* If we are faulting a kernel address, we have to use the
+ * kernel page tables.
+ */
+ mfspr r10, SPRN_SRR0 /* Get effective address of fault */
+ INVALIDATE_ADJACENT_PAGES_CPU15(r10)
+ mtspr SPRN_MD_EPN, r10
+#ifdef ITLB_MISS_KERNEL
+ mfcr r11
+ compare_to_kernel_boundary r10, r10
+#endif
+ mfspr r10, SPRN_M_TWB /* Get level 1 table */
+#ifdef ITLB_MISS_KERNEL
+ blt+ 3f
+ rlwinm r10, r10, 0, 20, 31
+ oris r10, r10, (swapper_pg_dir - PAGE_OFFSET)@ha
+3:
+ mtcr r11
+#endif
+ lwz r11, (swapper_pg_dir-PAGE_OFFSET)@l(r10) /* Get level 1 entry */
+ mtspr SPRN_MD_TWC, r11
+ mfspr r10, SPRN_MD_TWC
+ lwz r10, 0(r10) /* Get the pte */
+ rlwimi r11, r10, 0, _PAGE_GUARDED | _PAGE_ACCESSED
+ rlwimi r11, r10, 32 - 9, _PMD_PAGE_512K
+ mtspr SPRN_MI_TWC, r11
+ /* The Linux PTE won't go exactly into the MMU TLB.
+ * Software indicator bits 20 and 23 must be clear.
+ * Software indicator bits 22, 24, 25, 26, and 27 must be
+ * set. All other Linux PTE bits control the behavior
+ * of the MMU.
+ */
+ rlwinm r10, r10, 0, ~0x0f00 /* Clear bits 20-23 */
+ rlwimi r10, r10, 4, 0x0400 /* Copy _PAGE_EXEC into bit 21 */
+ ori r10, r10, RPN_PATTERN | 0x200 /* Set 22 and 24-27 */
+ mtspr SPRN_MI_RPN, r10 /* Update TLB entry */
+
+ /* Restore registers */
+0: mfspr r10, SPRN_SPRG_SCRATCH0
+ mfspr r11, SPRN_SPRG_SCRATCH1
+ rfi
+ patch_site 0b, patch__itlbmiss_exit_1
+
+#ifdef CONFIG_PERF_EVENTS
+ patch_site 0f, patch__itlbmiss_perf
+0: lwz r10, (itlb_miss_counter - PAGE_OFFSET)@l(0)
+ addi r10, r10, 1
+ stw r10, (itlb_miss_counter - PAGE_OFFSET)@l(0)
+ mfspr r10, SPRN_SPRG_SCRATCH0
+ mfspr r11, SPRN_SPRG_SCRATCH1
+ rfi
+#endif
+
+ . = 0x1200
+DataStoreTLBMiss:
+ mtspr SPRN_DAR, r10
+ mtspr SPRN_M_TW, r11
+ mfcr r11
+
+ /* If we are faulting a kernel address, we have to use the
+ * kernel page tables.
+ */
+ mfspr r10, SPRN_MD_EPN
+ compare_to_kernel_boundary r10, r10
+ mfspr r10, SPRN_M_TWB /* Get level 1 table */
+ blt+ 3f
+ rlwinm r10, r10, 0, 20, 31
+ oris r10, r10, (swapper_pg_dir - PAGE_OFFSET)@ha
+3:
+ mtcr r11
+ lwz r11, (swapper_pg_dir-PAGE_OFFSET)@l(r10) /* Get level 1 entry */
+
+ mtspr SPRN_MD_TWC, r11
+ mfspr r10, SPRN_MD_TWC
+ lwz r10, 0(r10) /* Get the pte */
+
+ /* Insert Guarded and Accessed flags into the TWC from the Linux PTE.
+ * It is bit 27 of both the Linux PTE and the TWC (at least
+ * I got that right :-). It will be better when we can put
+ * this into the Linux pgd/pmd and load it in the operation
+ * above.
+ */
+ rlwimi r11, r10, 0, _PAGE_GUARDED | _PAGE_ACCESSED
+ rlwimi r11, r10, 32 - 9, _PMD_PAGE_512K
+ mtspr SPRN_MD_TWC, r11
+
+ /* The Linux PTE won't go exactly into the MMU TLB.
+ * Software indicator bits 24, 25, 26, and 27 must be
+ * set. All other Linux PTE bits control the behavior
+ * of the MMU.
+ */
+ li r11, RPN_PATTERN
+ rlwimi r10, r11, 0, 24, 27 /* Set 24-27 */
+ mtspr SPRN_MD_RPN, r10 /* Update TLB entry */
+
+ /* Restore registers */
+
+0: mfspr r10, SPRN_DAR
+ mtspr SPRN_DAR, r11 /* Tag DAR */
+ mfspr r11, SPRN_M_TW
+ rfi
+ patch_site 0b, patch__dtlbmiss_exit_1
+
+#ifdef CONFIG_PERF_EVENTS
+ patch_site 0f, patch__dtlbmiss_perf
+0: lwz r10, (dtlb_miss_counter - PAGE_OFFSET)@l(0)
+ addi r10, r10, 1
+ stw r10, (dtlb_miss_counter - PAGE_OFFSET)@l(0)
+ mfspr r10, SPRN_DAR
+ mtspr SPRN_DAR, r11 /* Tag DAR */
+ mfspr r11, SPRN_M_TW
+ rfi
+#endif
+
+/* This is an instruction TLB error on the MPC8xx. This could be due
+ * to many reasons, such as executing guarded memory or illegal instruction
+ * addresses. There is nothing to do but handle a big time error fault.
+ */
+ . = 0x1300
+InstructionTLBError:
+ EXCEPTION_PROLOG
+ mr r4,r12
+ andis. r5,r9,DSISR_SRR1_MATCH_32S@h /* Filter relevant SRR1 bits */
+ andis. r10,r9,SRR1_ISI_NOPT@h
+ beq+ .Litlbie
+ tlbie r4
+ /* 0x400 is InstructionAccess exception, needed by bad_page_fault() */
+.Litlbie:
+ stw r4, _DAR(r11)
+ EXC_XFER_LITE(0x400, handle_page_fault)
+
+/* This is the data TLB error on the MPC8xx. This could be due to
+ * many reasons, including a dirty update to a pte. We bail out to
+ * a higher level function that can handle it.
+ */
+ . = 0x1400
+DataTLBError:
+ EXCEPTION_PROLOG_0 handle_dar_dsisr=1
+ mfspr r11, SPRN_DAR
+ cmpwi cr1, r11, RPN_PATTERN
+ beq- cr1, FixupDAR /* must be a buggy dcbX, icbi insn. */
+DARFixed:/* Return from dcbx instruction bug workaround */
+#ifdef CONFIG_VMAP_STACK
+ li r11, RPN_PATTERN
+ mtspr SPRN_DAR, r11 /* Tag DAR, to be used in DTLB Error */
+#endif
+ EXCEPTION_PROLOG_1
+ EXCEPTION_PROLOG_2 handle_dar_dsisr=1
+ get_and_save_dar_dsisr_on_stack r4, r5, r11
+ andis. r10,r5,DSISR_NOHPTE@h
+ beq+ .Ldtlbie
+ tlbie r4
+.Ldtlbie:
+#ifndef CONFIG_VMAP_STACK
+ li r10,RPN_PATTERN
+ mtspr SPRN_DAR,r10 /* Tag DAR, to be used in DTLB Error */
+#endif
+ /* 0x300 is DataAccess exception, needed by bad_page_fault() */
+ EXC_XFER_LITE(0x300, handle_page_fault)
+
+stack_overflow:
+ vmap_stack_overflow_exception
+
+/* On the MPC8xx, these next four traps are used for development
+ * support of breakpoints and such. Someday I will get around to
+ * using them.
+ */
+do_databreakpoint:
+ EXCEPTION_PROLOG_1
+ EXCEPTION_PROLOG_2 handle_dar_dsisr=1
+ addi r3,r1,STACK_FRAME_OVERHEAD
+ mfspr r4,SPRN_BAR
+ stw r4,_DAR(r11)
+#ifdef CONFIG_VMAP_STACK
+ lwz r5,_DSISR(r11)
+#else
+ mfspr r5,SPRN_DSISR
+#endif
+ EXC_XFER_STD(0x1c00, do_break)
+
+ . = 0x1c00
+DataBreakpoint:
+ EXCEPTION_PROLOG_0 handle_dar_dsisr=1
+ mfspr r11, SPRN_SRR0
+ cmplwi cr1, r11, (.Ldtlbie - PAGE_OFFSET)@l
+ cmplwi cr7, r11, (.Litlbie - PAGE_OFFSET)@l
+ cror 4*cr1+eq, 4*cr1+eq, 4*cr7+eq
+ bne cr1, do_databreakpoint
+ mtcr r10
+ mfspr r10, SPRN_SPRG_SCRATCH0
+ mfspr r11, SPRN_SPRG_SCRATCH1
+ rfi
+
+#ifdef CONFIG_PERF_EVENTS
+ . = 0x1d00
+InstructionBreakpoint:
+ mtspr SPRN_SPRG_SCRATCH0, r10
+ lwz r10, (instruction_counter - PAGE_OFFSET)@l(0)
+ addi r10, r10, -1
+ stw r10, (instruction_counter - PAGE_OFFSET)@l(0)
+ lis r10, 0xffff
+ ori r10, r10, 0x01
+ mtspr SPRN_COUNTA, r10
+ mfspr r10, SPRN_SPRG_SCRATCH0
+ rfi
+#else
+ EXCEPTION(0x1d00, Trap_1d, unknown_exception, EXC_XFER_STD)
+#endif
+ EXCEPTION(0x1e00, Trap_1e, unknown_exception, EXC_XFER_STD)
+ EXCEPTION(0x1f00, Trap_1f, unknown_exception, EXC_XFER_STD)
+
+ . = 0x2000
+
+/* This is the procedure to calculate the data EA for buggy dcbx,dcbi instructions
+ * by decoding the registers used by the dcbx instruction and adding them.
+ * DAR is set to the calculated address.
+ */
+FixupDAR:/* Entry point for dcbx workaround. */
+ mtspr SPRN_M_TW, r10
+ /* fetch instruction from memory. */
+ mfspr r10, SPRN_SRR0
+ mtspr SPRN_MD_EPN, r10
+ rlwinm r11, r10, 16, 0xfff8
+ cmpli cr1, r11, PAGE_OFFSET@h
+ mfspr r11, SPRN_M_TWB /* Get level 1 table */
+ blt+ cr1, 3f
+
+ /* create physical page address from effective address */
+ tophys(r11, r10)
+ mfspr r11, SPRN_M_TWB /* Get level 1 table */
+ rlwinm r11, r11, 0, 20, 31
+ oris r11, r11, (swapper_pg_dir - PAGE_OFFSET)@ha
+3:
+ lwz r11, (swapper_pg_dir-PAGE_OFFSET)@l(r11) /* Get the level 1 entry */
+ mtspr SPRN_MD_TWC, r11
+ mtcrf 0x01, r11
+ mfspr r11, SPRN_MD_TWC
+ lwz r11, 0(r11) /* Get the pte */
+ bt 28,200f /* bit 28 = Large page (8M) */
+ /* concat physical page address(r11) and page offset(r10) */
+ rlwimi r11, r10, 0, 32 - PAGE_SHIFT, 31
+201: lwz r11,0(r11)
+/* Check if it really is a dcbx instruction. */
+/* dcbt and dcbtst does not generate DTLB Misses/Errors,
+ * no need to include them here */
+ xoris r10, r11, 0x7c00 /* check if major OP code is 31 */
+ rlwinm r10, r10, 0, 21, 5
+ cmpwi cr1, r10, 2028 /* Is dcbz? */
+ beq+ cr1, 142f
+ cmpwi cr1, r10, 940 /* Is dcbi? */
+ beq+ cr1, 142f
+ cmpwi cr1, r10, 108 /* Is dcbst? */
+ beq+ cr1, 144f /* Fix up store bit! */
+ cmpwi cr1, r10, 172 /* Is dcbf? */
+ beq+ cr1, 142f
+ cmpwi cr1, r10, 1964 /* Is icbi? */
+ beq+ cr1, 142f
+141: mfspr r10,SPRN_M_TW
+ b DARFixed /* Nope, go back to normal TLB processing */
+
+200:
+ /* concat physical page address(r11) and page offset(r10) */
+ rlwimi r11, r10, 0, 32 - PAGE_SHIFT_8M, 31
+ b 201b
+
+144: mfspr r10, SPRN_DSISR
+ rlwinm r10, r10,0,7,5 /* Clear store bit for buggy dcbst insn */
+ mtspr SPRN_DSISR, r10
+142: /* continue, it was a dcbx, dcbi instruction. */
+ mfctr r10
+ mtdar r10 /* save ctr reg in DAR */
+ rlwinm r10, r11, 24, 24, 28 /* offset into jump table for reg RB */
+ addi r10, r10, 150f@l /* add start of table */
+ mtctr r10 /* load ctr with jump address */
+ xor r10, r10, r10 /* sum starts at zero */
+ bctr /* jump into table */
+150:
+ add r10, r10, r0 ;b 151f
+ add r10, r10, r1 ;b 151f
+ add r10, r10, r2 ;b 151f
+ add r10, r10, r3 ;b 151f
+ add r10, r10, r4 ;b 151f
+ add r10, r10, r5 ;b 151f
+ add r10, r10, r6 ;b 151f
+ add r10, r10, r7 ;b 151f
+ add r10, r10, r8 ;b 151f
+ add r10, r10, r9 ;b 151f
+ mtctr r11 ;b 154f /* r10 needs special handling */
+ mtctr r11 ;b 153f /* r11 needs special handling */
+ add r10, r10, r12 ;b 151f
+ add r10, r10, r13 ;b 151f
+ add r10, r10, r14 ;b 151f
+ add r10, r10, r15 ;b 151f
+ add r10, r10, r16 ;b 151f
+ add r10, r10, r17 ;b 151f
+ add r10, r10, r18 ;b 151f
+ add r10, r10, r19 ;b 151f
+ add r10, r10, r20 ;b 151f
+ add r10, r10, r21 ;b 151f
+ add r10, r10, r22 ;b 151f
+ add r10, r10, r23 ;b 151f
+ add r10, r10, r24 ;b 151f
+ add r10, r10, r25 ;b 151f
+ add r10, r10, r26 ;b 151f
+ add r10, r10, r27 ;b 151f
+ add r10, r10, r28 ;b 151f
+ add r10, r10, r29 ;b 151f
+ add r10, r10, r30 ;b 151f
+ add r10, r10, r31
+151:
+ rlwinm r11,r11,19,24,28 /* offset into jump table for reg RA */
+ cmpwi cr1, r11, 0
+ beq cr1, 152f /* if reg RA is zero, don't add it */
+ addi r11, r11, 150b@l /* add start of table */
+ mtctr r11 /* load ctr with jump address */
+ rlwinm r11,r11,0,16,10 /* make sure we don't execute this more than once */
+ bctr /* jump into table */
+152:
+ mfdar r11
+ mtctr r11 /* restore ctr reg from DAR */
+#ifdef CONFIG_VMAP_STACK
+ mfspr r11, SPRN_SPRG_THREAD
+ stw r10, DAR(r11)
+ mfspr r10, SPRN_DSISR
+ stw r10, DSISR(r11)
+#else
+ mtdar r10 /* save fault EA to DAR */
+#endif
+ mfspr r10,SPRN_M_TW
+ b DARFixed /* Go back to normal TLB handling */
+
+ /* special handling for r10,r11 since these are modified already */
+153: mfspr r11, SPRN_SPRG_SCRATCH1 /* load r11 from SPRN_SPRG_SCRATCH1 */
+ add r10, r10, r11 /* add it */
+ mfctr r11 /* restore r11 */
+ b 151b
+154: mfspr r11, SPRN_SPRG_SCRATCH0 /* load r10 from SPRN_SPRG_SCRATCH0 */
+ add r10, r10, r11 /* add it */
+ mfctr r11 /* restore r11 */
+ b 151b
+
+/*
+ * This is where the main kernel code starts.
+ */
+start_here:
+ /* ptr to current */
+ lis r2,init_task@h
+ ori r2,r2,init_task@l
+
+ /* ptr to phys current thread */
+ tophys(r4,r2)
+ addi r4,r4,THREAD /* init task's THREAD */
+ mtspr SPRN_SPRG_THREAD,r4
+
+ /* stack */
+ lis r1,init_thread_union@ha
+ addi r1,r1,init_thread_union@l
+ lis r0, STACK_END_MAGIC@h
+ ori r0, r0, STACK_END_MAGIC@l
+ stw r0, 0(r1)
+ li r0,0
+ stwu r0,THREAD_SIZE-STACK_FRAME_OVERHEAD(r1)
+
+ lis r6, swapper_pg_dir@ha
+ tophys(r6,r6)
+ mtspr SPRN_M_TWB, r6
+
+ bl early_init /* We have to do this with MMU on */
+
+/*
+ * Decide what sort of machine this is and initialize the MMU.
+ */
+#ifdef CONFIG_KASAN
+ bl kasan_early_init
+#endif
+ li r3,0
+ mr r4,r31
+ bl machine_init
+ bl MMU_init
+
+/*
+ * Go back to running unmapped so we can load up new values
+ * and change to using our exception vectors.
+ * On the 8xx, all we have to do is invalidate the TLB to clear
+ * the old 8M byte TLB mappings and load the page table base register.
+ */
+ /* The right way to do this would be to track it down through
+ * init's THREAD like the context switch code does, but this is
+ * easier......until someone changes init's static structures.
+ */
+ lis r4,2f@h
+ ori r4,r4,2f@l
+ tophys(r4,r4)
+ li r3,MSR_KERNEL & ~(MSR_IR|MSR_DR)
+ mtspr SPRN_SRR0,r4
+ mtspr SPRN_SRR1,r3
+ rfi
+/* Load up the kernel context */
+2:
+#ifdef CONFIG_PIN_TLB_IMMR
+ lis r0, MD_TWAM@h
+ oris r0, r0, 0x1f00
+ mtspr SPRN_MD_CTR, r0
+ LOAD_REG_IMMEDIATE(r0, VIRT_IMMR_BASE | MD_EVALID)
+ tlbie r0
+ mtspr SPRN_MD_EPN, r0
+ LOAD_REG_IMMEDIATE(r0, MD_SVALID | MD_PS512K | MD_GUARDED)
+ mtspr SPRN_MD_TWC, r0
+ mfspr r0, SPRN_IMMR
+ rlwinm r0, r0, 0, 0xfff80000
+ ori r0, r0, 0xf0 | _PAGE_DIRTY | _PAGE_SPS | _PAGE_SH | \
+ _PAGE_NO_CACHE | _PAGE_PRESENT
+ mtspr SPRN_MD_RPN, r0
+ lis r0, (MD_TWAM | MD_RSV4I)@h
+ mtspr SPRN_MD_CTR, r0
+#endif
+#ifndef CONFIG_PIN_TLB_TEXT
+ li r0, 0
+ mtspr SPRN_MI_CTR, r0
+#endif
+#if !defined(CONFIG_PIN_TLB_DATA) && !defined(CONFIG_PIN_TLB_IMMR)
+ lis r0, MD_TWAM@h
+ mtspr SPRN_MD_CTR, r0
+#endif
+ tlbia /* Clear all TLB entries */
+ sync /* wait for tlbia/tlbie to finish */
+
+ /* set up the PTE pointers for the Abatron bdiGDB.
+ */
+ lis r5, abatron_pteptrs@h
+ ori r5, r5, abatron_pteptrs@l
+ stw r5, 0xf0(0) /* Must match your Abatron config file */
+ tophys(r5,r5)
+ lis r6, swapper_pg_dir@h
+ ori r6, r6, swapper_pg_dir@l
+ stw r6, 0(r5)
+
+/* Now turn on the MMU for real! */
+ li r4,MSR_KERNEL
+ lis r3,start_kernel@h
+ ori r3,r3,start_kernel@l
+ mtspr SPRN_SRR0,r3
+ mtspr SPRN_SRR1,r4
+ rfi /* enable MMU and jump to start_kernel */
+
+/* Set up the initial MMU state so we can do the first level of
+ * kernel initialization. This maps the first 8 MBytes of memory 1:1
+ * virtual to physical. Also, set the cache mode since that is defined
+ * by TLB entries and perform any additional mapping (like of the IMMR).
+ * If configured to pin some TLBs, we pin the first 8 Mbytes of kernel,
+ * 24 Mbytes of data, and the 512k IMMR space. Anything not covered by
+ * these mappings is mapped by page tables.
+ */
+initial_mmu:
+ li r8, 0
+ mtspr SPRN_MI_CTR, r8 /* remove PINNED ITLB entries */
+ lis r10, MD_TWAM@h
+ mtspr SPRN_MD_CTR, r10 /* remove PINNED DTLB entries */
+
+ tlbia /* Invalidate all TLB entries */
+
+ lis r8, MI_APG_INIT@h /* Set protection modes */
+ ori r8, r8, MI_APG_INIT@l
+ mtspr SPRN_MI_AP, r8
+ lis r8, MD_APG_INIT@h
+ ori r8, r8, MD_APG_INIT@l
+ mtspr SPRN_MD_AP, r8
+
+ /* Map the lower RAM (up to 32 Mbytes) into the ITLB and DTLB */
+ lis r8, MI_RSV4I@h
+ ori r8, r8, 0x1c00
+ oris r12, r10, MD_RSV4I@h
+ ori r12, r12, 0x1c00
+ li r9, 4 /* up to 4 pages of 8M */
+ mtctr r9
+ lis r9, KERNELBASE@h /* Create vaddr for TLB */
+ li r10, MI_PS8MEG | _PMD_ACCESSED | MI_SVALID
+ li r11, MI_BOOTINIT /* Create RPN for address 0 */
+1:
+ mtspr SPRN_MI_CTR, r8 /* Set instruction MMU control */
+ addi r8, r8, 0x100
+ ori r0, r9, MI_EVALID /* Mark it valid */
+ mtspr SPRN_MI_EPN, r0
+ mtspr SPRN_MI_TWC, r10
+ mtspr SPRN_MI_RPN, r11 /* Store TLB entry */
+ mtspr SPRN_MD_CTR, r12
+ addi r12, r12, 0x100
+ mtspr SPRN_MD_EPN, r0
+ mtspr SPRN_MD_TWC, r10
+ mtspr SPRN_MD_RPN, r11
+ addis r9, r9, 0x80
+ addis r11, r11, 0x80
+
+ bdnz 1b
+
+ /* Since the cache is enabled according to the information we
+ * just loaded into the TLB, invalidate and enable the caches here.
+ * We should probably check/set other modes....later.
+ */
+ lis r8, IDC_INVALL@h
+ mtspr SPRN_IC_CST, r8
+ mtspr SPRN_DC_CST, r8
+ lis r8, IDC_ENABLE@h
+ mtspr SPRN_IC_CST, r8
+ mtspr SPRN_DC_CST, r8
+ /* Disable debug mode entry on breakpoints */
+ mfspr r8, SPRN_DER
+#ifdef CONFIG_PERF_EVENTS
+ rlwinm r8, r8, 0, ~0xc
+#else
+ rlwinm r8, r8, 0, ~0x8
+#endif
+ mtspr SPRN_DER, r8
+ blr
+
+#ifdef CONFIG_PIN_TLB
+_GLOBAL(mmu_pin_tlb)
+ lis r9, (1f - PAGE_OFFSET)@h
+ ori r9, r9, (1f - PAGE_OFFSET)@l
+ mfmsr r10
+ mflr r11
+ li r12, MSR_KERNEL & ~(MSR_IR | MSR_DR | MSR_RI)
+ rlwinm r0, r10, 0, ~MSR_RI
+ rlwinm r0, r0, 0, ~MSR_EE
+ mtmsr r0
+ isync
+ .align 4
+ mtspr SPRN_SRR0, r9
+ mtspr SPRN_SRR1, r12
+ rfi
+1:
+ li r5, 0
+ lis r6, MD_TWAM@h
+ mtspr SPRN_MI_CTR, r5
+ mtspr SPRN_MD_CTR, r6
+ tlbia
+
+#ifdef CONFIG_PIN_TLB_TEXT
+ LOAD_REG_IMMEDIATE(r5, 28 << 8)
+ LOAD_REG_IMMEDIATE(r6, PAGE_OFFSET)
+ LOAD_REG_IMMEDIATE(r7, MI_SVALID | MI_PS8MEG | _PMD_ACCESSED)
+ LOAD_REG_IMMEDIATE(r8, 0xf0 | _PAGE_RO | _PAGE_SPS | _PAGE_SH | _PAGE_PRESENT)
+ LOAD_REG_ADDR(r9, _sinittext)
+ li r0, 4
+ mtctr r0
+
+2: ori r0, r6, MI_EVALID
+ mtspr SPRN_MI_CTR, r5
+ mtspr SPRN_MI_EPN, r0
+ mtspr SPRN_MI_TWC, r7
+ mtspr SPRN_MI_RPN, r8
+ addi r5, r5, 0x100
+ addis r6, r6, SZ_8M@h
+ addis r8, r8, SZ_8M@h
+ cmplw r6, r9
+ bdnzt lt, 2b
+ lis r0, MI_RSV4I@h
+ mtspr SPRN_MI_CTR, r0
+#endif
+ LOAD_REG_IMMEDIATE(r5, 28 << 8 | MD_TWAM)
+#ifdef CONFIG_PIN_TLB_DATA
+ LOAD_REG_IMMEDIATE(r6, PAGE_OFFSET)
+ LOAD_REG_IMMEDIATE(r7, MI_SVALID | MI_PS8MEG | _PMD_ACCESSED)
+ li r8, 0
+#ifdef CONFIG_PIN_TLB_IMMR
+ li r0, 3
+#else
+ li r0, 4
+#endif
+ mtctr r0
+ cmpwi r4, 0
+ beq 4f
+ LOAD_REG_ADDR(r9, _sinittext)
+
+2: ori r0, r6, MD_EVALID
+ ori r12, r8, 0xf0 | _PAGE_RO | _PAGE_SPS | _PAGE_SH | _PAGE_PRESENT
+ mtspr SPRN_MD_CTR, r5
+ mtspr SPRN_MD_EPN, r0
+ mtspr SPRN_MD_TWC, r7
+ mtspr SPRN_MD_RPN, r12
+ addi r5, r5, 0x100
+ addis r6, r6, SZ_8M@h
+ addis r8, r8, SZ_8M@h
+ cmplw r6, r9
+ bdnzt lt, 2b
+4:
+2: ori r0, r6, MD_EVALID
+ ori r12, r8, 0xf0 | _PAGE_DIRTY | _PAGE_SPS | _PAGE_SH | _PAGE_PRESENT
+ mtspr SPRN_MD_CTR, r5
+ mtspr SPRN_MD_EPN, r0
+ mtspr SPRN_MD_TWC, r7
+ mtspr SPRN_MD_RPN, r12
+ addi r5, r5, 0x100
+ addis r6, r6, SZ_8M@h
+ addis r8, r8, SZ_8M@h
+ cmplw r6, r3
+ bdnzt lt, 2b
+#endif
+#ifdef CONFIG_PIN_TLB_IMMR
+ LOAD_REG_IMMEDIATE(r0, VIRT_IMMR_BASE | MD_EVALID)
+ LOAD_REG_IMMEDIATE(r7, MD_SVALID | MD_PS512K | MD_GUARDED | _PMD_ACCESSED)
+ mfspr r8, SPRN_IMMR
+ rlwinm r8, r8, 0, 0xfff80000
+ ori r8, r8, 0xf0 | _PAGE_DIRTY | _PAGE_SPS | _PAGE_SH | \
+ _PAGE_NO_CACHE | _PAGE_PRESENT
+ mtspr SPRN_MD_CTR, r5
+ mtspr SPRN_MD_EPN, r0
+ mtspr SPRN_MD_TWC, r7
+ mtspr SPRN_MD_RPN, r8
+#endif
+#if defined(CONFIG_PIN_TLB_IMMR) || defined(CONFIG_PIN_TLB_DATA)
+ lis r0, (MD_RSV4I | MD_TWAM)@h
+ mtspr SPRN_MD_CTR, r0
+#endif
+ mtspr SPRN_SRR1, r10
+ mtspr SPRN_SRR0, r11
+ rfi
+#endif /* CONFIG_PIN_TLB */
+
+/*
+ * 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
+ .globl sdata
+sdata:
+ .globl empty_zero_page
+ .align PAGE_SHIFT
+empty_zero_page:
+ .space PAGE_SIZE
+EXPORT_SYMBOL(empty_zero_page)
+
+ .globl swapper_pg_dir
+swapper_pg_dir:
+ .space PGD_TABLE_SIZE
+
+/* Room for two PTE table poiners, usually the kernel and current user
+ * pointer to their respective root page table (pgdir).
+ */
+ .globl abatron_pteptrs
+abatron_pteptrs:
+ .space 8