| /* |
| * 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. |
| * |
| * 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/cache.h> |
| #include <asm/pgtable.h> |
| #include <asm/cputable.h> |
| #include <asm/thread_info.h> |
| #include <asm/ppc_asm.h> |
| #include <asm/asm-offsets.h> |
| |
| /* Macro to make the code more readable. */ |
| #ifdef CONFIG_8xx_CPU6 |
| #define DO_8xx_CPU6(val, reg) \ |
| li reg, val; \ |
| stw reg, 12(r0); \ |
| lwz reg, 12(r0); |
| #else |
| #define DO_8xx_CPU6(val, reg) |
| #endif |
| .section .text.head, "ax" |
| _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. |
| * |
| * The TLB code currently contains a major hack. Since I use the condition |
| * code register, I have to save and restore it. I am out of registers, so |
| * I just store it in memory location 0 (the TLB handlers are not reentrant). |
| * To avoid making any decisions, I need to use the "segment" valid bit |
| * in the first level table, but that would require many changes to the |
| * Linux page directory/table functions that I don't want to do right now. |
| * |
| * I used to use SPRG2 for a temporary register in the TLB handler, but it |
| * has since been put to other uses. I now use a hack to save a register |
| * and the CCR at memory location 0.....Someday I'll fix this..... |
| * -- Dan |
| */ |
| .globl __start |
| __start: |
| mr r31,r3 /* save parameters */ |
| 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 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 |
| SYNC |
| rfi /* enables MMU */ |
| |
| /* |
| * Exception 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's thread_struct. |
| */ |
| #define EXCEPTION_PROLOG \ |
| mtspr SPRN_SPRG0,r10; \ |
| mtspr SPRN_SPRG1,r11; \ |
| mfcr r10; \ |
| EXCEPTION_PROLOG_1; \ |
| EXCEPTION_PROLOG_2 |
| |
| #define EXCEPTION_PROLOG_1 \ |
| mfspr r11,SPRN_SRR1; /* check whether user or kernel */ \ |
| andi. r11,r11,MSR_PR; \ |
| tophys(r11,r1); /* use tophys(r1) if kernel */ \ |
| beq 1f; \ |
| mfspr r11,SPRN_SPRG3; \ |
| lwz r11,THREAD_INFO-THREAD(r11); \ |
| addi r11,r11,THREAD_SIZE; \ |
| tophys(r11,r11); \ |
| 1: subi r11,r11,INT_FRAME_SIZE /* alloc exc. frame */ |
| |
| |
| #define EXCEPTION_PROLOG_2 \ |
| CLR_TOP32(r11); \ |
| stw r10,_CCR(r11); /* save 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 r12,SPRN_SRR0; \ |
| mfspr r9,SPRN_SRR1; \ |
| stw r1,GPR1(r11); \ |
| stw r1,0(r11); \ |
| tovirt(r1,r11); /* set new kernel sp */ \ |
| li r10,MSR_KERNEL & ~(MSR_IR|MSR_DR); /* can take exceptions */ \ |
| MTMSRD(r10); /* (except for mach check in rtas) */ \ |
| stw r0,GPR0(r11); \ |
| SAVE_4GPRS(3, r11); \ |
| SAVE_2GPRS(7, r11) |
| |
| /* |
| * Note: code which follows this uses cr0.eq (set if from kernel), |
| * r11, r12 (SRR0), and r9 (SRR1). |
| * |
| * Note2: once we have set r1 we are in a position to take exceptions |
| * again, and we could thus set MSR:RI at that point. |
| */ |
| |
| /* |
| * Exception vectors. |
| */ |
| #define EXCEPTION(n, label, hdlr, xfer) \ |
| . = n; \ |
| label: \ |
| EXCEPTION_PROLOG; \ |
| addi r3,r1,STACK_FRAME_OVERHEAD; \ |
| xfer(n, hdlr) |
| |
| #define EXC_XFER_TEMPLATE(n, hdlr, trap, copyee, tfer, ret) \ |
| li r10,trap; \ |
| stw r10,_TRAP(r11); \ |
| li r10,MSR_KERNEL; \ |
| copyee(r10, r9); \ |
| bl tfer; \ |
| i##n: \ |
| .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(n, hdlr, n, NOCOPY, transfer_to_handler_full, \ |
| ret_from_except_full) |
| |
| #define EXC_XFER_LITE(n, hdlr) \ |
| EXC_XFER_TEMPLATE(n, hdlr, n+1, NOCOPY, transfer_to_handler, \ |
| ret_from_except) |
| |
| #define EXC_XFER_EE(n, hdlr) \ |
| EXC_XFER_TEMPLATE(n, hdlr, n, COPY_EE, transfer_to_handler_full, \ |
| ret_from_except_full) |
| |
| #define EXC_XFER_EE_LITE(n, hdlr) \ |
| EXC_XFER_TEMPLATE(n, hdlr, n+1, COPY_EE, transfer_to_handler, \ |
| ret_from_except) |
| |
| /* System reset */ |
| EXCEPTION(0x100, Reset, unknown_exception, EXC_XFER_STD) |
| |
| /* Machine check */ |
| . = 0x200 |
| MachineCheck: |
| EXCEPTION_PROLOG |
| mfspr r4,SPRN_DAR |
| stw r4,_DAR(r11) |
| mfspr r5,SPRN_DSISR |
| stw r5,_DSISR(r11) |
| addi r3,r1,STACK_FRAME_OVERHEAD |
| EXC_XFER_STD(0x200, machine_check_exception) |
| |
| /* Data access exception. |
| * This is "never generated" by the MPC8xx. We jump to it for other |
| * translation errors. |
| */ |
| . = 0x300 |
| DataAccess: |
| EXCEPTION_PROLOG |
| mfspr r10,SPRN_DSISR |
| stw r10,_DSISR(r11) |
| mr r5,r10 |
| mfspr r4,SPRN_DAR |
| EXC_XFER_EE_LITE(0x300, handle_page_fault) |
| |
| /* Instruction access exception. |
| * This is "never generated" by the MPC8xx. We jump to it for other |
| * translation errors. |
| */ |
| . = 0x400 |
| InstructionAccess: |
| EXCEPTION_PROLOG |
| mr r4,r12 |
| mr r5,r9 |
| EXC_XFER_EE_LITE(0x400, handle_page_fault) |
| |
| /* External interrupt */ |
| EXCEPTION(0x500, HardwareInterrupt, do_IRQ, EXC_XFER_LITE) |
| |
| /* Alignment exception */ |
| . = 0x600 |
| Alignment: |
| EXCEPTION_PROLOG |
| mfspr r4,SPRN_DAR |
| stw r4,_DAR(r11) |
| mfspr r5,SPRN_DSISR |
| stw r5,_DSISR(r11) |
| addi r3,r1,STACK_FRAME_OVERHEAD |
| EXC_XFER_EE(0x600, alignment_exception) |
| |
| /* Program check exception */ |
| EXCEPTION(0x700, ProgramCheck, program_check_exception, EXC_XFER_STD) |
| |
| /* No FPU on MPC8xx. This exception is not supposed to happen. |
| */ |
| EXCEPTION(0x800, FPUnavailable, unknown_exception, EXC_XFER_STD) |
| |
| /* Decrementer */ |
| EXCEPTION(0x900, Decrementer, timer_interrupt, EXC_XFER_LITE) |
| |
| EXCEPTION(0xa00, Trap_0a, unknown_exception, EXC_XFER_EE) |
| EXCEPTION(0xb00, Trap_0b, unknown_exception, EXC_XFER_EE) |
| |
| /* System call */ |
| . = 0xc00 |
| SystemCall: |
| EXCEPTION_PROLOG |
| EXC_XFER_EE_LITE(0xc00, DoSyscall) |
| |
| /* Single step - not used on 601 */ |
| EXCEPTION(0xd00, SingleStep, single_step_exception, EXC_XFER_STD) |
| EXCEPTION(0xe00, Trap_0e, unknown_exception, EXC_XFER_EE) |
| EXCEPTION(0xf00, Trap_0f, unknown_exception, EXC_XFER_EE) |
| |
| /* On the MPC8xx, this is a software emulation interrupt. It occurs |
| * for all unimplemented and illegal instructions. |
| */ |
| EXCEPTION(0x1000, SoftEmu, SoftwareEmulation, EXC_XFER_STD) |
| |
| . = 0x1100 |
| /* |
| * For the MPC8xx, this is a software tablewalk to load the instruction |
| * TLB. It is modelled after the example in the Motorola manual. 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. |
| */ |
| InstructionTLBMiss: |
| #ifdef CONFIG_8xx_CPU6 |
| stw r3, 8(r0) |
| #endif |
| DO_8xx_CPU6(0x3f80, r3) |
| mtspr SPRN_M_TW, r10 /* Save a couple of working registers */ |
| mfcr r10 |
| stw r10, 0(r0) |
| stw r11, 4(r0) |
| mfspr r10, SPRN_SRR0 /* Get effective address of fault */ |
| #ifdef CONFIG_8xx_CPU15 |
| addi r11, r10, 0x1000 |
| tlbie r11 |
| addi r11, r10, -0x1000 |
| tlbie r11 |
| #endif |
| DO_8xx_CPU6(0x3780, r3) |
| mtspr SPRN_MD_EPN, r10 /* Have to use MD_EPN for walk, MI_EPN can't */ |
| mfspr r10, SPRN_M_TWB /* Get level 1 table entry address */ |
| |
| /* If we are faulting a kernel address, we have to use the |
| * kernel page tables. |
| */ |
| andi. r11, r10, 0x0800 /* Address >= 0x80000000 */ |
| beq 3f |
| lis r11, swapper_pg_dir@h |
| ori r11, r11, swapper_pg_dir@l |
| rlwimi r10, r11, 0, 2, 19 |
| 3: |
| lwz r11, 0(r10) /* Get the level 1 entry */ |
| rlwinm. r10, r11,0,0,19 /* Extract page descriptor page address */ |
| beq 2f /* If zero, don't try to find a pte */ |
| |
| /* We have a pte table, so load the MI_TWC with the attributes |
| * for this "segment." |
| */ |
| ori r11,r11,1 /* Set valid bit */ |
| DO_8xx_CPU6(0x2b80, r3) |
| mtspr SPRN_MI_TWC, r11 /* Set segment attributes */ |
| DO_8xx_CPU6(0x3b80, r3) |
| mtspr SPRN_MD_TWC, r11 /* Load pte table base address */ |
| mfspr r11, SPRN_MD_TWC /* ....and get the pte address */ |
| lwz r10, 0(r11) /* Get the pte */ |
| |
| #ifdef CONFIG_SWAP |
| /* do not set the _PAGE_ACCESSED bit of a non-present page */ |
| andi. r11, r10, _PAGE_PRESENT |
| beq 4f |
| ori r10, r10, _PAGE_ACCESSED |
| mfspr r11, SPRN_MD_TWC /* get the pte address again */ |
| stw r10, 0(r11) |
| 4: |
| #else |
| ori r10, r10, _PAGE_ACCESSED |
| stw r10, 0(r11) |
| #endif |
| |
| /* The Linux PTE won't go exactly into the MMU TLB. |
| * Software indicator bits 21, 22 and 28 must be clear. |
| * Software indicator bits 24, 25, 26, and 27 must be |
| * set. All other Linux PTE bits control the behavior |
| * of the MMU. |
| */ |
| 2: li r11, 0x00f0 |
| rlwimi r10, r11, 0, 24, 28 /* Set 24-27, clear 28 */ |
| DO_8xx_CPU6(0x2d80, r3) |
| mtspr SPRN_MI_RPN, r10 /* Update TLB entry */ |
| |
| mfspr r10, SPRN_M_TW /* Restore registers */ |
| lwz r11, 0(r0) |
| mtcr r11 |
| lwz r11, 4(r0) |
| #ifdef CONFIG_8xx_CPU6 |
| lwz r3, 8(r0) |
| #endif |
| rfi |
| |
| . = 0x1200 |
| DataStoreTLBMiss: |
| #ifdef CONFIG_8xx_CPU6 |
| stw r3, 8(r0) |
| #endif |
| DO_8xx_CPU6(0x3f80, r3) |
| mtspr SPRN_M_TW, r10 /* Save a couple of working registers */ |
| mfcr r10 |
| stw r10, 0(r0) |
| stw r11, 4(r0) |
| mfspr r10, SPRN_M_TWB /* Get level 1 table entry address */ |
| |
| /* If we are faulting a kernel address, we have to use the |
| * kernel page tables. |
| */ |
| andi. r11, r10, 0x0800 |
| beq 3f |
| lis r11, swapper_pg_dir@h |
| ori r11, r11, swapper_pg_dir@l |
| rlwimi r10, r11, 0, 2, 19 |
| 3: |
| lwz r11, 0(r10) /* Get the level 1 entry */ |
| rlwinm. r10, r11,0,0,19 /* Extract page descriptor page address */ |
| beq 2f /* If zero, don't try to find a pte */ |
| |
| /* We have a pte table, so load fetch the pte from the table. |
| */ |
| ori r11, r11, 1 /* Set valid bit in physical L2 page */ |
| DO_8xx_CPU6(0x3b80, r3) |
| mtspr SPRN_MD_TWC, r11 /* Load pte table base address */ |
| mfspr r10, SPRN_MD_TWC /* ....and get the pte address */ |
| lwz r10, 0(r10) /* Get the pte */ |
| |
| /* Insert the Guarded flag 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, 27, 27 |
| DO_8xx_CPU6(0x3b80, r3) |
| mtspr SPRN_MD_TWC, r11 |
| |
| #ifdef CONFIG_SWAP |
| /* do not set the _PAGE_ACCESSED bit of a non-present page */ |
| andi. r11, r10, _PAGE_PRESENT |
| beq 4f |
| ori r10, r10, _PAGE_ACCESSED |
| 4: |
| /* and update pte in table */ |
| #else |
| ori r10, r10, _PAGE_ACCESSED |
| #endif |
| mfspr r11, SPRN_MD_TWC /* get the pte address again */ |
| stw r10, 0(r11) |
| |
| /* The Linux PTE won't go exactly into the MMU TLB. |
| * Software indicator bits 21, 22 and 28 must be clear. |
| * Software indicator bits 24, 25, 26, and 27 must be |
| * set. All other Linux PTE bits control the behavior |
| * of the MMU. |
| */ |
| 2: li r11, 0x00f0 |
| rlwimi r10, r11, 0, 24, 28 /* Set 24-27, clear 28 */ |
| DO_8xx_CPU6(0x3d80, r3) |
| mtspr SPRN_MD_RPN, r10 /* Update TLB entry */ |
| |
| mfspr r10, SPRN_M_TW /* Restore registers */ |
| lwz r11, 0(r0) |
| mtcr r11 |
| lwz r11, 4(r0) |
| #ifdef CONFIG_8xx_CPU6 |
| lwz r3, 8(r0) |
| #endif |
| rfi |
| |
| /* 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: |
| b InstructionAccess |
| |
| /* This is the data TLB error on the MPC8xx. This could be due to |
| * many reasons, including a dirty update to a pte. We can catch that |
| * one here, but anything else is an error. First, we track down the |
| * Linux pte. If it is valid, write access is allowed, but the |
| * page dirty bit is not set, we will set it and reload the TLB. For |
| * any other case, we bail out to a higher level function that can |
| * handle it. |
| */ |
| . = 0x1400 |
| DataTLBError: |
| #ifdef CONFIG_8xx_CPU6 |
| stw r3, 8(r0) |
| #endif |
| DO_8xx_CPU6(0x3f80, r3) |
| mtspr SPRN_M_TW, r10 /* Save a couple of working registers */ |
| mfcr r10 |
| stw r10, 0(r0) |
| stw r11, 4(r0) |
| |
| /* First, make sure this was a store operation. |
| */ |
| mfspr r10, SPRN_DSISR |
| andis. r11, r10, 0x0200 /* If set, indicates store op */ |
| beq 2f |
| |
| /* The EA of a data TLB miss is automatically stored in the MD_EPN |
| * register. The EA of a data TLB error is automatically stored in |
| * the DAR, but not the MD_EPN register. We must copy the 20 most |
| * significant bits of the EA from the DAR to MD_EPN before we |
| * start walking the page tables. We also need to copy the CASID |
| * value from the M_CASID register. |
| * Addendum: The EA of a data TLB error is _supposed_ to be stored |
| * in DAR, but it seems that this doesn't happen in some cases, such |
| * as when the error is due to a dcbi instruction to a page with a |
| * TLB that doesn't have the changed bit set. In such cases, there |
| * does not appear to be any way to recover the EA of the error |
| * since it is neither in DAR nor MD_EPN. As a workaround, the |
| * _PAGE_HWWRITE bit is set for all kernel data pages when the PTEs |
| * are initialized in mapin_ram(). This will avoid the problem, |
| * assuming we only use the dcbi instruction on kernel addresses. |
| */ |
| mfspr r10, SPRN_DAR |
| rlwinm r11, r10, 0, 0, 19 |
| ori r11, r11, MD_EVALID |
| mfspr r10, SPRN_M_CASID |
| rlwimi r11, r10, 0, 28, 31 |
| DO_8xx_CPU6(0x3780, r3) |
| mtspr SPRN_MD_EPN, r11 |
| |
| mfspr r10, SPRN_M_TWB /* Get level 1 table entry address */ |
| |
| /* If we are faulting a kernel address, we have to use the |
| * kernel page tables. |
| */ |
| andi. r11, r10, 0x0800 |
| beq 3f |
| lis r11, swapper_pg_dir@h |
| ori r11, r11, swapper_pg_dir@l |
| rlwimi r10, r11, 0, 2, 19 |
| 3: |
| lwz r11, 0(r10) /* Get the level 1 entry */ |
| rlwinm. r10, r11,0,0,19 /* Extract page descriptor page address */ |
| beq 2f /* If zero, bail */ |
| |
| /* We have a pte table, so fetch the pte from the table. |
| */ |
| ori r11, r11, 1 /* Set valid bit in physical L2 page */ |
| DO_8xx_CPU6(0x3b80, r3) |
| mtspr SPRN_MD_TWC, r11 /* Load pte table base address */ |
| mfspr r11, SPRN_MD_TWC /* ....and get the pte address */ |
| lwz r10, 0(r11) /* Get the pte */ |
| |
| andi. r11, r10, _PAGE_RW /* Is it writeable? */ |
| beq 2f /* Bail out if not */ |
| |
| /* Update 'changed', among others. |
| */ |
| #ifdef CONFIG_SWAP |
| ori r10, r10, _PAGE_DIRTY|_PAGE_HWWRITE |
| /* do not set the _PAGE_ACCESSED bit of a non-present page */ |
| andi. r11, r10, _PAGE_PRESENT |
| beq 4f |
| ori r10, r10, _PAGE_ACCESSED |
| 4: |
| #else |
| ori r10, r10, _PAGE_DIRTY|_PAGE_ACCESSED|_PAGE_HWWRITE |
| #endif |
| mfspr r11, SPRN_MD_TWC /* Get pte address again */ |
| stw r10, 0(r11) /* and update pte in table */ |
| |
| /* The Linux PTE won't go exactly into the MMU TLB. |
| * Software indicator bits 21, 22 and 28 must be clear. |
| * Software indicator bits 24, 25, 26, and 27 must be |
| * set. All other Linux PTE bits control the behavior |
| * of the MMU. |
| */ |
| li r11, 0x00f0 |
| rlwimi r10, r11, 0, 24, 28 /* Set 24-27, clear 28 */ |
| DO_8xx_CPU6(0x3d80, r3) |
| mtspr SPRN_MD_RPN, r10 /* Update TLB entry */ |
| |
| mfspr r10, SPRN_M_TW /* Restore registers */ |
| lwz r11, 0(r0) |
| mtcr r11 |
| lwz r11, 4(r0) |
| #ifdef CONFIG_8xx_CPU6 |
| lwz r3, 8(r0) |
| #endif |
| rfi |
| 2: |
| mfspr r10, SPRN_M_TW /* Restore registers */ |
| lwz r11, 0(r0) |
| mtcr r11 |
| lwz r11, 4(r0) |
| #ifdef CONFIG_8xx_CPU6 |
| lwz r3, 8(r0) |
| #endif |
| b DataAccess |
| |
| EXCEPTION(0x1500, Trap_15, unknown_exception, EXC_XFER_EE) |
| EXCEPTION(0x1600, Trap_16, unknown_exception, EXC_XFER_EE) |
| EXCEPTION(0x1700, Trap_17, unknown_exception, EXC_XFER_EE) |
| 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) |
| |
| /* On the MPC8xx, these next four traps are used for development |
| * support of breakpoints and such. Someday I will get around to |
| * using them. |
| */ |
| 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) |
| |
| . = 0x2000 |
| |
| .globl giveup_fpu |
| 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 |
| li r3,0 |
| mtspr SPRN_SPRG2,r3 /* 0 => r1 has kernel sp */ |
| |
| /* 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 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 r6, swapper_pg_dir@h |
| ori r6, r6, swapper_pg_dir@l |
| tophys(r6,r6) |
| #ifdef CONFIG_8xx_CPU6 |
| lis r4, cpu6_errata_word@h |
| ori r4, r4, cpu6_errata_word@l |
| li r3, 0x3980 |
| stw r3, 12(r4) |
| lwz r3, 12(r4) |
| #endif |
| mtspr SPRN_M_TWB, r6 |
| 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: |
| SYNC /* Force all PTE updates to finish */ |
| tlbia /* Clear all TLB entries */ |
| sync /* wait for tlbia/tlbie to finish */ |
| TLBSYNC /* ... on all CPUs */ |
| |
| /* set up the PTE pointers for the Abatron bdiGDB. |
| */ |
| tovirt(r6,r6) |
| 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! */ |
| 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 8M IMMR space. Anything not covered by |
| * these mappings is mapped by page tables. |
| */ |
| initial_mmu: |
| tlbia /* Invalidate all TLB entries */ |
| #ifdef CONFIG_PIN_TLB |
| lis r8, MI_RSV4I@h |
| ori r8, r8, 0x1c00 |
| #else |
| li r8, 0 |
| #endif |
| mtspr SPRN_MI_CTR, r8 /* Set instruction MMU control */ |
| |
| #ifdef CONFIG_PIN_TLB |
| lis r10, (MD_RSV4I | MD_RESETVAL)@h |
| ori r10, r10, 0x1c00 |
| mr r8, r10 |
| #else |
| lis r10, MD_RESETVAL@h |
| #endif |
| #ifndef CONFIG_8xx_COPYBACK |
| oris r10, r10, MD_WTDEF@h |
| #endif |
| mtspr SPRN_MD_CTR, r10 /* Set data TLB control */ |
| |
| /* Now map the lower 8 Meg into the TLBs. For this quick hack, |
| * we can load the instruction and data TLB registers with the |
| * same values. |
| */ |
| lis r8, KERNELBASE@h /* Create vaddr for TLB */ |
| ori r8, r8, MI_EVALID /* Mark it valid */ |
| mtspr SPRN_MI_EPN, r8 |
| mtspr SPRN_MD_EPN, r8 |
| li r8, MI_PS8MEG /* Set 8M byte page */ |
| ori r8, r8, MI_SVALID /* Make it valid */ |
| mtspr SPRN_MI_TWC, r8 |
| mtspr SPRN_MD_TWC, r8 |
| li r8, MI_BOOTINIT /* Create RPN for address 0 */ |
| mtspr SPRN_MI_RPN, r8 /* Store TLB entry */ |
| mtspr SPRN_MD_RPN, r8 |
| lis r8, MI_Kp@h /* Set the protection mode */ |
| mtspr SPRN_MI_AP, r8 |
| mtspr SPRN_MD_AP, r8 |
| |
| /* Map another 8 MByte at the IMMR to get the processor |
| * internal registers (among other things). |
| */ |
| #ifdef CONFIG_PIN_TLB |
| addi r10, r10, 0x0100 |
| mtspr SPRN_MD_CTR, r10 |
| #endif |
| mfspr r9, 638 /* Get current IMMR */ |
| andis. r9, r9, 0xff80 /* Get 8Mbyte boundary */ |
| |
| mr r8, r9 /* Create vaddr for TLB */ |
| ori r8, r8, MD_EVALID /* Mark it valid */ |
| mtspr SPRN_MD_EPN, r8 |
| li r8, MD_PS8MEG /* Set 8M byte page */ |
| ori r8, r8, MD_SVALID /* Make it valid */ |
| mtspr SPRN_MD_TWC, r8 |
| mr r8, r9 /* Create paddr for TLB */ |
| ori r8, r8, MI_BOOTINIT|0x2 /* Inhibit cache -- Cort */ |
| mtspr SPRN_MD_RPN, r8 |
| |
| #ifdef CONFIG_PIN_TLB |
| /* Map two more 8M kernel data pages. |
| */ |
| addi r10, r10, 0x0100 |
| mtspr SPRN_MD_CTR, r10 |
| |
| lis r8, KERNELBASE@h /* Create vaddr for TLB */ |
| addis r8, r8, 0x0080 /* Add 8M */ |
| ori r8, r8, MI_EVALID /* Mark it valid */ |
| mtspr SPRN_MD_EPN, r8 |
| li r9, MI_PS8MEG /* Set 8M byte page */ |
| ori r9, r9, MI_SVALID /* Make it valid */ |
| mtspr SPRN_MD_TWC, r9 |
| li r11, MI_BOOTINIT /* Create RPN for address 0 */ |
| addis r11, r11, 0x0080 /* Add 8M */ |
| mtspr SPRN_MD_RPN, r11 |
| |
| addis r8, r8, 0x0080 /* Add 8M */ |
| mtspr SPRN_MD_EPN, r8 |
| mtspr SPRN_MD_TWC, r9 |
| addis r11, r11, 0x0080 /* Add 8M */ |
| mtspr SPRN_MD_RPN, r11 |
| #endif |
| |
| /* 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 |
| #ifdef CONFIG_8xx_COPYBACK |
| mtspr SPRN_DC_CST, r8 |
| #else |
| /* For a debug option, I left this here to easily enable |
| * the write through cache mode |
| */ |
| lis r8, DC_SFWT@h |
| mtspr SPRN_DC_CST, r8 |
| lis r8, IDC_ENABLE@h |
| mtspr SPRN_DC_CST, r8 |
| #endif |
| blr |
| |
| |
| /* |
| * Set up to use a given MMU context. |
| * r3 is context number, r4 is PGD pointer. |
| * |
| * We place the physical address of the new task page directory loaded |
| * into the MMU base register, and set the ASID compare register with |
| * the new "context." |
| */ |
| _GLOBAL(set_context) |
| |
| #ifdef CONFIG_BDI_SWITCH |
| /* Context switch the PTE pointer for the Abatron BDI2000. |
| * The PGDIR is passed as second argument. |
| */ |
| lis r5, KERNELBASE@h |
| lwz r5, 0xf0(r5) |
| stw r4, 0x4(r5) |
| #endif |
| |
| #ifdef CONFIG_8xx_CPU6 |
| lis r6, cpu6_errata_word@h |
| ori r6, r6, cpu6_errata_word@l |
| tophys (r4, r4) |
| li r7, 0x3980 |
| stw r7, 12(r6) |
| lwz r7, 12(r6) |
| mtspr SPRN_M_TWB, r4 /* Update MMU base address */ |
| li r7, 0x3380 |
| stw r7, 12(r6) |
| lwz r7, 12(r6) |
| mtspr SPRN_M_CASID, r3 /* Update context */ |
| #else |
| mtspr SPRN_M_CASID,r3 /* Update context */ |
| tophys (r4, r4) |
| mtspr SPRN_M_TWB, r4 /* and pgd */ |
| #endif |
| SYNC |
| blr |
| |
| #ifdef CONFIG_8xx_CPU6 |
| /* It's here because it is unique to the 8xx. |
| * It is important we get called with interrupts disabled. I used to |
| * do that, but it appears that all code that calls this already had |
| * interrupt disabled. |
| */ |
| .globl set_dec_cpu6 |
| set_dec_cpu6: |
| lis r7, cpu6_errata_word@h |
| ori r7, r7, cpu6_errata_word@l |
| li r4, 0x2c00 |
| stw r4, 8(r7) |
| lwz r4, 8(r7) |
| mtspr 22, r3 /* Update Decrementer */ |
| SYNC |
| blr |
| #endif |
| |
| /* |
| * 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 |
| empty_zero_page: |
| .space 4096 |
| |
| .globl swapper_pg_dir |
| swapper_pg_dir: |
| .space 4096 |
| |
| /* Room for two PTE table poiners, usually the kernel and current user |
| * pointer to their respective root page table (pgdir). |
| */ |
| abatron_pteptrs: |
| .space 8 |
| |
| #ifdef CONFIG_8xx_CPU6 |
| .globl cpu6_errata_word |
| cpu6_errata_word: |
| .space 16 |
| #endif |
| |
