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-rw-r--r--arch/ppc/kernel/head_4xx.S1021
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-/*
- * 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
- *
- *
- * Module name: head_4xx.S
- *
- * Description:
- * Kernel execution entry point code.
- *
- * 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 <asm/processor.h>
-#include <asm/page.h>
-#include <asm/mmu.h>
-#include <asm/pgtable.h>
-#include <asm/ibm4xx.h>
-#include <asm/cputable.h>
-#include <asm/thread_info.h>
-#include <asm/ppc_asm.h>
-#include <asm/asm-offsets.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=96m")
- * r7 - End of kernel command line string
- *
- * This is all going to change RSN when we add bi_recs....... -- Dan
- */
- .text
-_GLOBAL(_stext)
-_GLOBAL(_start)
-
- /* Save parameters we are passed.
- */
- mr r31,r3
- mr r30,r4
- mr r29,r5
- mr r28,r6
- mr r27,r7
-
- /* We have to turn on the MMU right away so we get cache modes
- * set correctly.
- */
- bl initial_mmu
-
-/* We now have the lower 16 Meg mapped into TLB entries, and the caches
- * ready to work.
- */
-turn_on_mmu:
- lis r0,MSR_KERNEL@h
- ori r0,r0,MSR_KERNEL@l
- mtspr SPRN_SRR1,r0
- lis r0,start_here@h
- ori r0,r0,start_here@l
- mtspr SPRN_SRR0,r0
- SYNC
- rfi /* enables MMU */
- b . /* prevent prefetch past rfi */
-
-/*
- * This area is used for temporarily saving registers during the
- * critical exception prolog.
- */
- . = 0xc0
-crit_save:
-_GLOBAL(crit_r10)
- .space 4
-_GLOBAL(crit_r11)
- .space 4
-
-/*
- * Exception vector entry code. This code runs with address translation
- * turned off (i.e. using physical addresses). We assume SPRG3 has the
- * physical address of the current task thread_struct.
- * Note that we have to have decremented r1 before we write to any fields
- * of the exception frame, since a critical interrupt could occur at any
- * time, and it will write to the area immediately below the current r1.
- */
-#define NORMAL_EXCEPTION_PROLOG \
- mtspr SPRN_SPRG0,r10; /* save two registers to work with */\
- mtspr SPRN_SPRG1,r11; \
- mtspr SPRN_SPRG2,r1; \
- mfcr r10; /* save CR in r10 for now */\
- mfspr r11,SPRN_SRR1; /* check whether user or kernel */\
- andi. r11,r11,MSR_PR; \
- beq 1f; \
- mfspr r1,SPRN_SPRG3; /* if from user, start at top of */\
- lwz r1,THREAD_INFO-THREAD(r1); /* this thread's kernel stack */\
- addi r1,r1,THREAD_SIZE; \
-1: subi r1,r1,INT_FRAME_SIZE; /* Allocate an exception frame */\
- tophys(r11,r1); \
- stw r10,_CCR(r11); /* save various registers */\
- stw r12,GPR12(r11); \
- stw r9,GPR9(r11); \
- mfspr r10,SPRN_SPRG0; \
- stw r10,GPR10(r11); \
- mfspr r12,SPRN_SPRG1; \
- stw r12,GPR11(r11); \
- mflr r10; \
- stw r10,_LINK(r11); \
- mfspr r10,SPRN_SPRG2; \
- mfspr r12,SPRN_SRR0; \
- stw r10,GPR1(r11); \
- mfspr r9,SPRN_SRR1; \
- stw r10,0(r11); \
- rlwinm r9,r9,0,14,12; /* clear MSR_WE (necessary?) */\
- stw r0,GPR0(r11); \
- SAVE_4GPRS(3, r11); \
- SAVE_2GPRS(7, r11)
-
-/*
- * Exception prolog for critical exceptions. This is a little different
- * from the normal exception prolog above since a critical exception
- * can potentially occur at any point during normal exception processing.
- * Thus we cannot use the same SPRG registers as the normal prolog above.
- * Instead we use a couple of words of memory at low physical addresses.
- * This is OK since we don't support SMP on these processors.
- */
-#define CRITICAL_EXCEPTION_PROLOG \
- stw r10,crit_r10@l(0); /* save two registers to work with */\
- stw r11,crit_r11@l(0); \
- mfcr r10; /* save CR in r10 for now */\
- mfspr r11,SPRN_SRR3; /* check whether user or kernel */\
- andi. r11,r11,MSR_PR; \
- lis r11,critical_stack_top@h; \
- ori r11,r11,critical_stack_top@l; \
- beq 1f; \
- /* COMING FROM USER MODE */ \
- mfspr r11,SPRN_SPRG3; /* if from user, start at top of */\
- lwz r11,THREAD_INFO-THREAD(r11); /* this thread's kernel stack */\
- addi r11,r11,THREAD_SIZE; \
-1: subi r11,r11,INT_FRAME_SIZE; /* Allocate an exception frame */\
- tophys(r11,r11); \
- stw r10,_CCR(r11); /* save various registers */\
- stw r12,GPR12(r11); \
- stw r9,GPR9(r11); \
- mflr r10; \
- stw r10,_LINK(r11); \
- mfspr r12,SPRN_DEAR; /* save DEAR and ESR in the frame */\
- stw r12,_DEAR(r11); /* since they may have had stuff */\
- mfspr r9,SPRN_ESR; /* in them at the point where the */\
- stw r9,_ESR(r11); /* exception was taken */\
- mfspr r12,SPRN_SRR2; \
- stw r1,GPR1(r11); \
- mfspr r9,SPRN_SRR3; \
- stw r1,0(r11); \
- tovirt(r1,r11); \
- rlwinm r9,r9,0,14,12; /* clear MSR_WE (necessary?) */\
- stw r0,GPR0(r11); \
- SAVE_4GPRS(3, r11); \
- SAVE_2GPRS(7, r11)
-
- /*
- * State at this point:
- * r9 saved in stack frame, now saved SRR3 & ~MSR_WE
- * r10 saved in crit_r10 and in stack frame, trashed
- * r11 saved in crit_r11 and in stack frame,
- * now phys stack/exception frame pointer
- * r12 saved in stack frame, now saved SRR2
- * CR saved in stack frame, CR0.EQ = !SRR3.PR
- * LR, DEAR, ESR in stack frame
- * r1 saved in stack frame, now virt stack/excframe pointer
- * r0, r3-r8 saved in stack frame
- */
-
-/*
- * Exception vectors.
- */
-#define START_EXCEPTION(n, label) \
- . = n; \
-label:
-
-#define EXCEPTION(n, label, hdlr, xfer) \
- START_EXCEPTION(n, label); \
- NORMAL_EXCEPTION_PROLOG; \
- addi r3,r1,STACK_FRAME_OVERHEAD; \
- xfer(n, hdlr)
-
-#define CRITICAL_EXCEPTION(n, label, hdlr) \
- START_EXCEPTION(n, label); \
- CRITICAL_EXCEPTION_PROLOG; \
- addi r3,r1,STACK_FRAME_OVERHEAD; \
- EXC_XFER_TEMPLATE(hdlr, n+2, (MSR_KERNEL & ~(MSR_ME|MSR_DE|MSR_CE)), \
- NOCOPY, crit_transfer_to_handler, \
- ret_from_crit_exc)
-
-#define EXC_XFER_TEMPLATE(hdlr, trap, msr, copyee, tfer, ret) \
- li r10,trap; \
- stw r10,TRAP(r11); \
- lis r10,msr@h; \
- ori r10,r10,msr@l; \
- copyee(r10, r9); \
- bl tfer; \
- .long hdlr; \
- .long ret
-
-#define COPY_EE(d, s) rlwimi d,s,0,16,16
-#define NOCOPY(d, s)
-
-#define EXC_XFER_STD(n, hdlr) \
- EXC_XFER_TEMPLATE(hdlr, n, MSR_KERNEL, NOCOPY, transfer_to_handler_full, \
- ret_from_except_full)
-
-#define EXC_XFER_LITE(n, hdlr) \
- EXC_XFER_TEMPLATE(hdlr, n+1, MSR_KERNEL, NOCOPY, transfer_to_handler, \
- ret_from_except)
-
-#define EXC_XFER_EE(n, hdlr) \
- EXC_XFER_TEMPLATE(hdlr, n, MSR_KERNEL, COPY_EE, transfer_to_handler_full, \
- ret_from_except_full)
-
-#define EXC_XFER_EE_LITE(n, hdlr) \
- EXC_XFER_TEMPLATE(hdlr, n+1, MSR_KERNEL, COPY_EE, transfer_to_handler, \
- ret_from_except)
-
-
-/*
- * 0x0100 - Critical Interrupt Exception
- */
- CRITICAL_EXCEPTION(0x0100, CriticalInterrupt, unknown_exception)
-
-/*
- * 0x0200 - Machine Check Exception
- */
- CRITICAL_EXCEPTION(0x0200, MachineCheck, machine_check_exception)
-
-/*
- * 0x0300 - Data Storage Exception
- * This happens for just a few reasons. U0 set (but we don't do that),
- * or zone protection fault (user violation, write to protected page).
- * If this is just an update of modified status, we do that quickly
- * and exit. Otherwise, we call heavywight functions to do the work.
- */
- START_EXCEPTION(0x0300, DataStorage)
- mtspr SPRN_SPRG0, r10 /* Save some working registers */
- mtspr SPRN_SPRG1, r11
-#ifdef CONFIG_403GCX
- stw r12, 0(r0)
- stw r9, 4(r0)
- mfcr r11
- mfspr r12, SPRN_PID
- stw r11, 8(r0)
- stw r12, 12(r0)
-#else
- mtspr SPRN_SPRG4, r12
- mtspr SPRN_SPRG5, r9
- mfcr r11
- mfspr r12, SPRN_PID
- mtspr SPRN_SPRG7, r11
- mtspr SPRN_SPRG6, r12
-#endif
-
- /* First, check if it was a zone fault (which means a user
- * tried to access a kernel or read-protected page - always
- * a SEGV). All other faults here must be stores, so no
- * need to check ESR_DST as well. */
- mfspr r10, SPRN_ESR
- andis. r10, r10, ESR_DIZ@h
- bne 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
- li r9, 0
- mtspr SPRN_PID, r9 /* TLB will have 0 TID */
- b 4f
-
- /* Get the PGD for the current thread.
- */
-3:
- mfspr r11,SPRN_SPRG3
- lwz r11,PGDIR(r11)
-4:
- tophys(r11, r11)
- rlwimi r11, r10, 12, 20, 29 /* Create L1 (pgdir/pmd) address */
- lwz r11, 0(r11) /* Get L1 entry */
- rlwinm. r12, r11, 0, 0, 19 /* Extract L2 (pte) base address */
- beq 2f /* Bail if no table */
-
- rlwimi r12, r10, 22, 20, 29 /* Compute PTE address */
- lwz r11, 0(r12) /* Get Linux PTE */
-
- andi. r9, r11, _PAGE_RW /* Is it writeable? */
- beq 2f /* Bail if not */
-
- /* Update 'changed'.
- */
- ori r11, r11, _PAGE_DIRTY|_PAGE_ACCESSED|_PAGE_HWWRITE
- stw r11, 0(r12) /* Update Linux page table */
-
- /* Most of the Linux PTE is ready to load into the TLB LO.
- * We set ZSEL, where only the LS-bit determines user access.
- * 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.
- */
- li r12, 0x0ce2
- andc r11, r11, r12 /* Make sure 20, 21 are zero */
-
- /* find the TLB index that caused the fault. It has to be here.
- */
- tlbsx r9, 0, r10
-
- tlbwe r11, r9, TLB_DATA /* Load TLB LO */
-
- /* Done...restore registers and get out of here.
- */
-#ifdef CONFIG_403GCX
- lwz r12, 12(r0)
- lwz r11, 8(r0)
- mtspr SPRN_PID, r12
- mtcr r11
- lwz r9, 4(r0)
- lwz r12, 0(r0)
-#else
- mfspr r12, SPRN_SPRG6
- mfspr r11, SPRN_SPRG7
- mtspr SPRN_PID, r12
- mtcr r11
- mfspr r9, SPRN_SPRG5
- mfspr r12, SPRN_SPRG4
-#endif
- mfspr r11, SPRN_SPRG1
- mfspr r10, SPRN_SPRG0
- PPC405_ERR77_SYNC
- rfi /* Should sync shadow TLBs */
- b . /* prevent prefetch past rfi */
-
-2:
- /* The bailout. Restore registers to pre-exception conditions
- * and call the heavyweights to help us out.
- */
-#ifdef CONFIG_403GCX
- lwz r12, 12(r0)
- lwz r11, 8(r0)
- mtspr SPRN_PID, r12
- mtcr r11
- lwz r9, 4(r0)
- lwz r12, 0(r0)
-#else
- mfspr r12, SPRN_SPRG6
- mfspr r11, SPRN_SPRG7
- mtspr SPRN_PID, r12
- mtcr r11
- mfspr r9, SPRN_SPRG5
- mfspr r12, SPRN_SPRG4
-#endif
- mfspr r11, SPRN_SPRG1
- mfspr r10, SPRN_SPRG0
- b DataAccess
-
-/*
- * 0x0400 - Instruction Storage Exception
- * This is caused by a fetch from non-execute or guarded pages.
- */
- START_EXCEPTION(0x0400, InstructionAccess)
- NORMAL_EXCEPTION_PROLOG
- mr r4,r12 /* Pass SRR0 as arg2 */
- li r5,0 /* Pass zero as arg3 */
- EXC_XFER_EE_LITE(0x400, handle_page_fault)
-
-/* 0x0500 - External Interrupt Exception */
- EXCEPTION(0x0500, HardwareInterrupt, do_IRQ, EXC_XFER_LITE)
-
-/* 0x0600 - Alignment Exception */
- START_EXCEPTION(0x0600, Alignment)
- NORMAL_EXCEPTION_PROLOG
- mfspr r4,SPRN_DEAR /* Grab the DEAR and save it */
- stw r4,_DEAR(r11)
- addi r3,r1,STACK_FRAME_OVERHEAD
- EXC_XFER_EE(0x600, alignment_exception)
-
-/* 0x0700 - Program Exception */
- START_EXCEPTION(0x0700, ProgramCheck)
- NORMAL_EXCEPTION_PROLOG
- mfspr r4,SPRN_ESR /* Grab the ESR and save it */
- stw r4,_ESR(r11)
- addi r3,r1,STACK_FRAME_OVERHEAD
- EXC_XFER_STD(0x700, program_check_exception)
-
- EXCEPTION(0x0800, Trap_08, unknown_exception, EXC_XFER_EE)
- EXCEPTION(0x0900, Trap_09, unknown_exception, EXC_XFER_EE)
- EXCEPTION(0x0A00, Trap_0A, unknown_exception, EXC_XFER_EE)
- EXCEPTION(0x0B00, Trap_0B, unknown_exception, EXC_XFER_EE)
-
-/* 0x0C00 - System Call Exception */
- START_EXCEPTION(0x0C00, SystemCall)
- NORMAL_EXCEPTION_PROLOG
- EXC_XFER_EE_LITE(0xc00, DoSyscall)
-
- EXCEPTION(0x0D00, Trap_0D, unknown_exception, EXC_XFER_EE)
- EXCEPTION(0x0E00, Trap_0E, unknown_exception, EXC_XFER_EE)
- EXCEPTION(0x0F00, Trap_0F, unknown_exception, EXC_XFER_EE)
-
-/* 0x1000 - Programmable Interval Timer (PIT) Exception */
- START_EXCEPTION(0x1000, Decrementer)
- NORMAL_EXCEPTION_PROLOG
- lis r0,TSR_PIS@h
- mtspr SPRN_TSR,r0 /* Clear the PIT exception */
- addi r3,r1,STACK_FRAME_OVERHEAD
- EXC_XFER_LITE(0x1000, timer_interrupt)
-
-#if 0
-/* NOTE:
- * FIT and WDT handlers are not implemented yet.
- */
-
-/* 0x1010 - Fixed Interval Timer (FIT) Exception
-*/
- STND_EXCEPTION(0x1010, FITException, unknown_exception)
-
-/* 0x1020 - Watchdog Timer (WDT) Exception
-*/
-#ifdef CONFIG_BOOKE_WDT
- CRITICAL_EXCEPTION(0x1020, WDTException, WatchdogException)
-#else
- CRITICAL_EXCEPTION(0x1020, WDTException, unknown_exception)
-#endif
-#endif
-
-/* 0x1100 - Data TLB Miss Exception
- * As the name implies, translation is not in the MMU, so search the
- * page tables and fix it. The only purpose of this function is to
- * load TLB entries from the page table if they exist.
- */
- START_EXCEPTION(0x1100, DTLBMiss)
- mtspr SPRN_SPRG0, r10 /* Save some working registers */
- mtspr SPRN_SPRG1, r11
-#ifdef CONFIG_403GCX
- stw r12, 0(r0)
- stw r9, 4(r0)
- mfcr r11
- mfspr r12, SPRN_PID
- stw r11, 8(r0)
- stw r12, 12(r0)
-#else
- mtspr SPRN_SPRG4, r12
- mtspr SPRN_SPRG5, r9
- mfcr r11
- mfspr r12, SPRN_PID
- mtspr SPRN_SPRG7, r11
- mtspr SPRN_SPRG6, r12
-#endif
- 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
- li r9, 0
- mtspr SPRN_PID, r9 /* TLB will have 0 TID */
- b 4f
-
- /* Get the PGD for the current thread.
- */
-3:
- mfspr r11,SPRN_SPRG3
- lwz r11,PGDIR(r11)
-4:
- tophys(r11, r11)
- rlwimi r11, r10, 12, 20, 29 /* Create L1 (pgdir/pmd) address */
- lwz r12, 0(r11) /* Get L1 entry */
- andi. r9, r12, _PMD_PRESENT /* Check if it points to a PTE page */
- beq 2f /* Bail if no table */
-
- rlwimi r12, r10, 22, 20, 29 /* Compute PTE address */
- lwz r11, 0(r12) /* Get Linux PTE */
- andi. r9, r11, _PAGE_PRESENT
- beq 5f
-
- ori r11, r11, _PAGE_ACCESSED
- stw r11, 0(r12)
-
- /* Create TLB tag. This is the faulting address plus a static
- * set of bits. These are size, valid, E, U0.
- */
- li r12, 0x00c0
- rlwimi r10, r12, 0, 20, 31
-
- b finish_tlb_load
-
-2: /* Check for possible large-page pmd entry */
- rlwinm. r9, r12, 2, 22, 24
- beq 5f
-
- /* Create TLB tag. This is the faulting address, plus a static
- * set of bits (valid, E, U0) plus the size from the PMD.
- */
- ori r9, r9, 0x40
- rlwimi r10, r9, 0, 20, 31
- mr r11, r12
-
- b finish_tlb_load
-
-5:
- /* The bailout. Restore registers to pre-exception conditions
- * and call the heavyweights to help us out.
- */
-#ifdef CONFIG_403GCX
- lwz r12, 12(r0)
- lwz r11, 8(r0)
- mtspr SPRN_PID, r12
- mtcr r11
- lwz r9, 4(r0)
- lwz r12, 0(r0)
-#else
- mfspr r12, SPRN_SPRG6
- mfspr r11, SPRN_SPRG7
- mtspr SPRN_PID, r12
- mtcr r11
- mfspr r9, SPRN_SPRG5
- mfspr r12, SPRN_SPRG4
-#endif
- mfspr r11, SPRN_SPRG1
- mfspr r10, SPRN_SPRG0
- b DataAccess
-
-/* 0x1200 - Instruction TLB Miss Exception
- * Nearly the same as above, except we get our information from different
- * registers and bailout to a different point.
- */
- START_EXCEPTION(0x1200, ITLBMiss)
- mtspr SPRN_SPRG0, r10 /* Save some working registers */
- mtspr SPRN_SPRG1, r11
-#ifdef CONFIG_403GCX
- stw r12, 0(r0)
- stw r9, 4(r0)
- mfcr r11
- mfspr r12, SPRN_PID
- stw r11, 8(r0)
- stw r12, 12(r0)
-#else
- mtspr SPRN_SPRG4, r12
- mtspr SPRN_SPRG5, r9
- mfcr r11
- mfspr r12, SPRN_PID
- mtspr SPRN_SPRG7, r11
- mtspr SPRN_SPRG6, r12
-#endif
- 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
- li r9, 0
- mtspr SPRN_PID, r9 /* TLB will have 0 TID */
- b 4f
-
- /* Get the PGD for the current thread.
- */
-3:
- mfspr r11,SPRN_SPRG3
- lwz r11,PGDIR(r11)
-4:
- tophys(r11, r11)
- rlwimi r11, r10, 12, 20, 29 /* Create L1 (pgdir/pmd) address */
- lwz r12, 0(r11) /* Get L1 entry */
- andi. r9, r12, _PMD_PRESENT /* Check if it points to a PTE page */
- beq 2f /* Bail if no table */
-
- rlwimi r12, r10, 22, 20, 29 /* Compute PTE address */
- lwz r11, 0(r12) /* Get Linux PTE */
- andi. r9, r11, _PAGE_PRESENT
- beq 5f
-
- ori r11, r11, _PAGE_ACCESSED
- stw r11, 0(r12)
-
- /* Create TLB tag. This is the faulting address plus a static
- * set of bits. These are size, valid, E, U0.
- */
- li r12, 0x00c0
- rlwimi r10, r12, 0, 20, 31
-
- b finish_tlb_load
-
-2: /* Check for possible large-page pmd entry */
- rlwinm. r9, r12, 2, 22, 24
- beq 5f
-
- /* Create TLB tag. This is the faulting address, plus a static
- * set of bits (valid, E, U0) plus the size from the PMD.
- */
- ori r9, r9, 0x40
- rlwimi r10, r9, 0, 20, 31
- mr r11, r12
-
- b finish_tlb_load
-
-5:
- /* The bailout. Restore registers to pre-exception conditions
- * and call the heavyweights to help us out.
- */
-#ifdef CONFIG_403GCX
- lwz r12, 12(r0)
- lwz r11, 8(r0)
- mtspr SPRN_PID, r12
- mtcr r11
- lwz r9, 4(r0)
- lwz r12, 0(r0)
-#else
- mfspr r12, SPRN_SPRG6
- mfspr r11, SPRN_SPRG7
- mtspr SPRN_PID, r12
- mtcr r11
- mfspr r9, SPRN_SPRG5
- mfspr r12, SPRN_SPRG4
-#endif
- mfspr r11, SPRN_SPRG1
- mfspr r10, SPRN_SPRG0
- b InstructionAccess
-
- EXCEPTION(0x1300, Trap_13, unknown_exception, EXC_XFER_EE)
- EXCEPTION(0x1400, Trap_14, unknown_exception, EXC_XFER_EE)
- EXCEPTION(0x1500, Trap_15, unknown_exception, EXC_XFER_EE)
- EXCEPTION(0x1600, Trap_16, unknown_exception, EXC_XFER_EE)
-#ifdef CONFIG_IBM405_ERR51
- /* 405GP errata 51 */
- START_EXCEPTION(0x1700, Trap_17)
- b DTLBMiss
-#else
- EXCEPTION(0x1700, Trap_17, unknown_exception, EXC_XFER_EE)
-#endif
- EXCEPTION(0x1800, Trap_18, unknown_exception, EXC_XFER_EE)
- EXCEPTION(0x1900, Trap_19, unknown_exception, EXC_XFER_EE)
- EXCEPTION(0x1A00, Trap_1A, unknown_exception, EXC_XFER_EE)
- EXCEPTION(0x1B00, Trap_1B, unknown_exception, EXC_XFER_EE)
- EXCEPTION(0x1C00, Trap_1C, unknown_exception, EXC_XFER_EE)
- EXCEPTION(0x1D00, Trap_1D, unknown_exception, EXC_XFER_EE)
- EXCEPTION(0x1E00, Trap_1E, unknown_exception, EXC_XFER_EE)
- EXCEPTION(0x1F00, Trap_1F, unknown_exception, EXC_XFER_EE)
-
-/* Check for a single step debug exception while in an exception
- * handler before state has been saved. This is to catch the case
- * where an instruction that we are trying to single step causes
- * an exception (eg ITLB/DTLB miss) and thus the first instruction of
- * the exception handler generates a single step debug exception.
- *
- * If we get a debug trap on the first instruction of an exception handler,
- * we reset the MSR_DE in the _exception handler's_ MSR (the debug trap is
- * a critical exception, so we are using SPRN_CSRR1 to manipulate the MSR).
- * The exception handler was handling a non-critical interrupt, so it will
- * save (and later restore) the MSR via SPRN_SRR1, which will still have
- * the MSR_DE bit set.
- */
- /* 0x2000 - Debug Exception */
- START_EXCEPTION(0x2000, DebugTrap)
- CRITICAL_EXCEPTION_PROLOG
-
- /*
- * If this is a single step or branch-taken exception in an
- * exception entry sequence, it was probably meant to apply to
- * the code where the exception occurred (since exception entry
- * doesn't turn off DE automatically). We simulate the effect
- * of turning off DE on entry to an exception handler by turning
- * off DE in the SRR3 value and clearing the debug status.
- */
- mfspr r10,SPRN_DBSR /* check single-step/branch taken */
- andis. r10,r10,DBSR_IC@h
- beq+ 2f
-
- andi. r10,r9,MSR_IR|MSR_PR /* check supervisor + MMU off */
- beq 1f /* branch and fix it up */
-
- mfspr r10,SPRN_SRR2 /* Faulting instruction address */
- cmplwi r10,0x2100
- bgt+ 2f /* address above exception vectors */
-
- /* here it looks like we got an inappropriate debug exception. */
-1: rlwinm r9,r9,0,~MSR_DE /* clear DE in the SRR3 value */
- lis r10,DBSR_IC@h /* clear the IC event */
- mtspr SPRN_DBSR,r10
- /* restore state and get out */
- lwz r10,_CCR(r11)
- lwz r0,GPR0(r11)
- lwz r1,GPR1(r11)
- mtcrf 0x80,r10
- mtspr SPRN_SRR2,r12
- mtspr SPRN_SRR3,r9
- lwz r9,GPR9(r11)
- lwz r12,GPR12(r11)
- lwz r10,crit_r10@l(0)
- lwz r11,crit_r11@l(0)
- PPC405_ERR77_SYNC
- rfci
- b .
-
- /* continue normal handling for a critical exception... */
-2: mfspr r4,SPRN_DBSR
- addi r3,r1,STACK_FRAME_OVERHEAD
- EXC_XFER_TEMPLATE(DebugException, 0x2002, \
- (MSR_KERNEL & ~(MSR_ME|MSR_DE|MSR_CE)), \
- NOCOPY, crit_transfer_to_handler, ret_from_crit_exc)
-
-/*
- * The other Data TLB exceptions bail out to this point
- * if they can't resolve the lightweight TLB fault.
- */
-DataAccess:
- 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(0x300, handle_page_fault)
-
-/* Other PowerPC processors, namely those derived from the 6xx-series
- * have vectors from 0x2100 through 0x2F00 defined, but marked as reserved.
- * However, for the 4xx-series processors these are neither defined nor
- * reserved.
- */
-
- /* Damn, I came up one instruction too many to fit into the
- * exception space :-). Both the instruction and data TLB
- * miss get to this point to load the TLB.
- * r10 - TLB_TAG value
- * r11 - Linux PTE
- * r12, r9 - avilable to use
- * PID - loaded with proper value when we get here
- * Upon exit, we reload everything and RFI.
- * Actually, it will fit now, but oh well.....a common place
- * to load the TLB.
- */
-tlb_4xx_index:
- .long 0
-finish_tlb_load:
- /* load the next available TLB index.
- */
- lwz r9, tlb_4xx_index@l(0)
- addi r9, r9, 1
- andi. r9, r9, (PPC4XX_TLB_SIZE-1)
- stw r9, tlb_4xx_index@l(0)
-
-6:
- /*
- * Clear out the software-only bits in the PTE to generate the
- * TLB_DATA value. These are the bottom 2 bits of the RPM, the
- * top 3 bits of the zone field, and M.
- */
- li r12, 0x0ce2
- andc r11, r11, r12
-
- tlbwe r11, r9, TLB_DATA /* Load TLB LO */
- tlbwe r10, r9, TLB_TAG /* Load TLB HI */
-
- /* Done...restore registers and get out of here.
- */
-#ifdef CONFIG_403GCX
- lwz r12, 12(r0)
- lwz r11, 8(r0)
- mtspr SPRN_PID, r12
- mtcr r11
- lwz r9, 4(r0)
- lwz r12, 0(r0)
-#else
- mfspr r12, SPRN_SPRG6
- mfspr r11, SPRN_SPRG7
- mtspr SPRN_PID, r12
- mtcr r11
- mfspr r9, SPRN_SPRG5
- mfspr r12, SPRN_SPRG4
-#endif
- mfspr r11, SPRN_SPRG1
- mfspr r10, SPRN_SPRG0
- PPC405_ERR77_SYNC
- rfi /* Should sync shadow TLBs */
- b . /* prevent prefetch past rfi */
-
-/* extern void giveup_fpu(struct task_struct *prev)
- *
- * The PowerPC 4xx family of processors do not have an FPU, so this just
- * returns.
- */
-_GLOBAL(giveup_fpu)
- blr
-
-/* 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_SPRG3,r4
-
- /* stack */
- lis r1,init_thread_union@ha
- addi r1,r1,init_thread_union@l
- li r0,0
- stwu r0,THREAD_SIZE-STACK_FRAME_OVERHEAD(r1)
-
- bl early_init /* We have to do this with MMU on */
-
-/*
- * 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
-
-/* Go back to running unmapped so we can load up new values
- * and change to using our exception vectors.
- * On the 4xx, all we have to do is invalidate the TLB to clear
- * the old 16M byte TLB mappings.
- */
- lis r4,2f@h
- ori r4,r4,2f@l
- tophys(r4,r4)
- lis r3,(MSR_KERNEL & ~(MSR_IR|MSR_DR))@h
- ori r3,r3,(MSR_KERNEL & ~(MSR_IR|MSR_DR))@l
- mtspr SPRN_SRR0,r4
- mtspr SPRN_SRR1,r3
- rfi
- b . /* prevent prefetch past rfi */
-
-/* Load up the kernel context */
-2:
- sync /* Flush to memory before changing TLB */
- tlbia
- isync /* Flush shadow TLBs */
-
- /* set up the 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
- stw r5, 0xf0(r0) /* Must match your Abatron config file */
- tophys(r5,r5)
- stw r6, 0(r5)
-
-/* Now turn on the MMU for real! */
- lis r4,MSR_KERNEL@h
- ori r4,r4,MSR_KERNEL@l
- 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 */
- b . /* prevent prefetch past rfi */
-
-/* Set up the initial MMU state so we can do the first level of
- * kernel initialization. This maps the first 16 MBytes of memory 1:1
- * virtual to physical and more importantly sets the cache mode.
- */
-initial_mmu:
- tlbia /* Invalidate all TLB entries */
- isync
-
- /* We should still be executing code at physical address 0x0000xxxx
- * at this point. However, start_here is at virtual address
- * 0xC000xxxx. So, set up a TLB mapping to cover this once
- * translation is enabled.
- */
-
- lis r3,KERNELBASE@h /* Load the kernel virtual address */
- ori r3,r3,KERNELBASE@l
- tophys(r4,r3) /* Load the kernel physical address */
-
- iccci r0,r3 /* Invalidate the i-cache before use */
-
- /* Load the kernel PID.
- */
- li r0,0
- mtspr SPRN_PID,r0
- sync
-
- /* Configure and load two entries into TLB slots 62 and 63.
- * In case we are pinning TLBs, these are reserved in by the
- * other TLB functions. If not reserving, then it doesn't
- * matter where they are loaded.
- */
- clrrwi r4,r4,10 /* Mask off the real page number */
- ori r4,r4,(TLB_WR | TLB_EX) /* Set the write and execute bits */
-
- clrrwi r3,r3,10 /* Mask off the effective page number */
- ori r3,r3,(TLB_VALID | TLB_PAGESZ(PAGESZ_16M))
-
- li r0,63 /* TLB slot 63 */
-
- tlbwe r4,r0,TLB_DATA /* Load the data portion of the entry */
- tlbwe r3,r0,TLB_TAG /* Load the tag portion of the entry */
-
-#if defined(CONFIG_SERIAL_TEXT_DEBUG) && defined(SERIAL_DEBUG_IO_BASE)
-
- /* Load a TLB entry for the UART, so that ppc4xx_progress() can use
- * the UARTs nice and early. We use a 4k real==virtual mapping. */
-
- lis r3,SERIAL_DEBUG_IO_BASE@h
- ori r3,r3,SERIAL_DEBUG_IO_BASE@l
- mr r4,r3
- clrrwi r4,r4,12
- ori r4,r4,(TLB_WR|TLB_I|TLB_M|TLB_G)
-
- clrrwi r3,r3,12
- ori r3,r3,(TLB_VALID | TLB_PAGESZ(PAGESZ_4K))
-
- li r0,0 /* TLB slot 0 */
- tlbwe r4,r0,TLB_DATA
- tlbwe r3,r0,TLB_TAG
-#endif /* CONFIG_SERIAL_DEBUG_TEXT && SERIAL_DEBUG_IO_BASE */
-
- isync
-
- /* Establish the exception vector base
- */
- lis r4,KERNELBASE@h /* EVPR only uses the high 16-bits */
- tophys(r0,r4) /* Use the physical address */
- mtspr SPRN_EVPR,r0
-
- blr
-
-_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, KERNELBASE@h
- lwz r5, 0xf0(r5)
- stw r4, 0x4(r5)
-#endif
- sync
- mtspr SPRN_PID,r3
- isync /* Need an isync to flush shadow */
- /* TLBs after changing PID */
- blr
-
-/* We put a few things here that have to be page-aligned. This stuff
- * goes at the beginning of the data segment, which is page-aligned.
- */
- .data
- .align 12
- .globl sdata
-sdata:
- .globl empty_zero_page
-empty_zero_page:
- .space 4096
- .globl swapper_pg_dir
-swapper_pg_dir:
- .space 4096
-
-
-/* Stack for handling critical exceptions from kernel mode */
- .section .bss
- .align 12
-exception_stack_bottom:
- .space 4096
-critical_stack_top:
- .globl exception_stack_top
-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.
- */
- .globl cmd_line
-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