diff options
Diffstat (limited to 'arch/powerpc/kernel/head_8xx.S')
| -rw-r--r-- | arch/powerpc/kernel/head_8xx.S | 1070 |
1 files changed, 1070 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S new file mode 100644 index 000000000..08c16aa0d --- /dev/null +++ b/arch/powerpc/kernel/head_8xx.S @@ -0,0 +1,1070 @@ +/* + * 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 <linux/init.h> +#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> +#include <asm/ptrace.h> +#include <asm/export.h> + +#if CONFIG_TASK_SIZE <= 0x80000000 && CONFIG_PAGE_OFFSET >= 0x80000000 +/* By simply checking Address >= 0x80000000, we know if its a kernel address */ +#define SIMPLE_KERNEL_ADDRESS 1 +#endif + +/* + * 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 */ + +/* + * 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_SPRG_SCRATCH0, r10; \ + mtspr SPRN_SPRG_SCRATCH1, 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_SPRG_THREAD; \ + 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 \ + stw r10,_CCR(r11); /* save registers */ \ + stw r12,GPR12(r11); \ + stw r9,GPR9(r11); \ + mfspr r10,SPRN_SPRG_SCRATCH0; \ + stw r10,GPR10(r11); \ + mfspr r12,SPRN_SPRG_SCRATCH1; \ + 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 */ \ + mtmsr r10; \ + 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, system_reset_exception, EXC_XFER_STD) + +/* Machine check */ + . = 0x200 +MachineCheck: + EXCEPTION_PROLOG + mfspr r4,SPRN_DAR + stw r4,_DAR(r11) + li r5,RPN_PATTERN + mtspr SPRN_DAR,r5 /* Tag DAR, to be used in DTLB Error */ + 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. + */ + . = 0x300 +DataAccess: + +/* Instruction access exception. + * This is "never generated" by the MPC8xx. + */ + . = 0x400 +InstructionAccess: + +/* External interrupt */ + EXCEPTION(0x500, HardwareInterrupt, do_IRQ, EXC_XFER_LITE) + +/* Alignment exception */ + . = 0x600 +Alignment: + EXCEPTION_PROLOG + mfspr r4,SPRN_DAR + stw r4,_DAR(r11) + li r5,RPN_PATTERN + mtspr SPRN_DAR,r5 /* Tag DAR, to be used in DTLB Error */ + 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, 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_TW 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(tmp, addr) \ + addi tmp, addr, PAGE_SIZE; \ + tlbie tmp; \ + addi tmp, addr, -PAGE_SIZE; \ + tlbie tmp +#else +#define INVALIDATE_ADJACENT_PAGES_CPU15(tmp, addr) +#endif + +InstructionTLBMiss: + mtspr SPRN_SPRG_SCRATCH0, r10 + mtspr SPRN_SPRG_SCRATCH1, r11 +#if defined(ITLB_MISS_KERNEL) || defined(CONFIG_HUGETLB_PAGE) + mtspr SPRN_SPRG_SCRATCH2, r12 +#endif + + /* 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(r11, r10) + /* Only modules will cause ITLB Misses as we always + * pin the first 8MB of kernel memory */ +#if defined(ITLB_MISS_KERNEL) || defined(CONFIG_HUGETLB_PAGE) + mfcr r12 +#endif +#ifdef ITLB_MISS_KERNEL +#if defined(SIMPLE_KERNEL_ADDRESS) && defined(CONFIG_PIN_TLB_TEXT) + andis. r11, r10, 0x8000 /* Address >= 0x80000000 */ +#else + rlwinm r11, r10, 16, 0xfff8 + cmpli cr0, r11, PAGE_OFFSET@h +#ifndef CONFIG_PIN_TLB_TEXT + /* It is assumed that kernel code fits into the first 8M page */ +_ENTRY(ITLBMiss_cmp) + cmpli cr7, r11, (PAGE_OFFSET + 0x0800000)@h +#endif +#endif +#endif + mfspr r11, SPRN_M_TW /* Get level 1 table */ +#ifdef ITLB_MISS_KERNEL +#if defined(SIMPLE_KERNEL_ADDRESS) && defined(CONFIG_PIN_TLB_TEXT) + beq+ 3f +#else + blt+ 3f +#endif +#ifndef CONFIG_PIN_TLB_TEXT + blt cr7, ITLBMissLinear +#endif + lis r11, (swapper_pg_dir-PAGE_OFFSET)@ha +3: +#endif + /* Insert level 1 index */ + rlwimi r11, r10, 32 - ((PAGE_SHIFT - 2) << 1), (PAGE_SHIFT - 2) << 1, 29 + lwz r11, (swapper_pg_dir-PAGE_OFFSET)@l(r11) /* Get the level 1 entry */ + + /* Extract level 2 index */ + rlwinm r10, r10, 32 - (PAGE_SHIFT - 2), 32 - PAGE_SHIFT, 29 +#ifdef CONFIG_HUGETLB_PAGE + mtcr r11 + bt- 28, 10f /* bit 28 = Large page (8M) */ + bt- 29, 20f /* bit 29 = Large page (8M or 512k) */ +#endif + rlwimi r10, r11, 0, 0, 32 - PAGE_SHIFT - 1 /* Add level 2 base */ + lwz r10, 0(r10) /* Get the pte */ +4: +#if defined(ITLB_MISS_KERNEL) || defined(CONFIG_HUGETLB_PAGE) + mtcr r12 +#endif + /* Load the MI_TWC with the attributes for this "segment." */ + mtspr SPRN_MI_TWC, r11 /* Set segment attributes */ + + rlwinm r11, r10, 32-7, _PAGE_PRESENT + and r11, r11, r10 + rlwimi r10, r11, 0, _PAGE_PRESENT + li r11, RPN_PATTERN | 0x200 + /* 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. + */ + rlwimi r11, r10, 4, 0x0400 /* Copy _PAGE_EXEC into bit 21 */ + rlwimi r10, r11, 0, 0x0ff0 /* Set 22, 24-27, clear 20,23 */ + mtspr SPRN_MI_RPN, r10 /* Update TLB entry */ + + /* Restore registers */ +_ENTRY(itlb_miss_exit_1) + mfspr r10, SPRN_SPRG_SCRATCH0 + mfspr r11, SPRN_SPRG_SCRATCH1 +#if defined(ITLB_MISS_KERNEL) || defined(CONFIG_HUGETLB_PAGE) + mfspr r12, SPRN_SPRG_SCRATCH2 +#endif + rfi +#ifdef CONFIG_PERF_EVENTS +_ENTRY(itlb_miss_perf) + lis r10, (itlb_miss_counter - PAGE_OFFSET)@ha + lwz r11, (itlb_miss_counter - PAGE_OFFSET)@l(r10) + addi r11, r11, 1 + stw r11, (itlb_miss_counter - PAGE_OFFSET)@l(r10) +#endif + mfspr r10, SPRN_SPRG_SCRATCH0 + mfspr r11, SPRN_SPRG_SCRATCH1 +#if defined(ITLB_MISS_KERNEL) || defined(CONFIG_HUGETLB_PAGE) + mfspr r12, SPRN_SPRG_SCRATCH2 +#endif + rfi + +#ifdef CONFIG_HUGETLB_PAGE +10: /* 8M pages */ +#ifdef CONFIG_PPC_16K_PAGES + /* Extract level 2 index */ + rlwinm r10, r10, 32 - (PAGE_SHIFT_8M - PAGE_SHIFT), 32 + PAGE_SHIFT_8M - (PAGE_SHIFT << 1), 29 + /* Add level 2 base */ + rlwimi r10, r11, 0, 0, 32 + PAGE_SHIFT_8M - (PAGE_SHIFT << 1) - 1 +#else + /* Level 2 base */ + rlwinm r10, r11, 0, ~HUGEPD_SHIFT_MASK +#endif + lwz r10, 0(r10) /* Get the pte */ + b 4b + +20: /* 512k pages */ + /* Extract level 2 index */ + rlwinm r10, r10, 32 - (PAGE_SHIFT_512K - PAGE_SHIFT), 32 + PAGE_SHIFT_512K - (PAGE_SHIFT << 1), 29 + /* Add level 2 base */ + rlwimi r10, r11, 0, 0, 32 + PAGE_SHIFT_512K - (PAGE_SHIFT << 1) - 1 + lwz r10, 0(r10) /* Get the pte */ + b 4b +#endif + + . = 0x1200 +DataStoreTLBMiss: + mtspr SPRN_SPRG_SCRATCH0, r10 + mtspr SPRN_SPRG_SCRATCH1, r11 + mtspr SPRN_SPRG_SCRATCH2, r12 + mfcr r12 + + /* If we are faulting a kernel address, we have to use the + * kernel page tables. + */ + mfspr r10, SPRN_MD_EPN + rlwinm r11, r10, 16, 0xfff8 + cmpli cr0, r11, PAGE_OFFSET@h + mfspr r11, SPRN_M_TW /* Get level 1 table */ + blt+ 3f + rlwinm r11, r10, 16, 0xfff8 +#ifndef CONFIG_PIN_TLB_IMMR + cmpli cr0, r11, VIRT_IMMR_BASE@h +#endif +_ENTRY(DTLBMiss_cmp) + cmpli cr7, r11, (PAGE_OFFSET + 0x1800000)@h +#ifndef CONFIG_PIN_TLB_IMMR +_ENTRY(DTLBMiss_jmp) + beq- DTLBMissIMMR +#endif + blt cr7, DTLBMissLinear + lis r11, (swapper_pg_dir-PAGE_OFFSET)@ha +3: + + /* Insert level 1 index */ + rlwimi r11, r10, 32 - ((PAGE_SHIFT - 2) << 1), (PAGE_SHIFT - 2) << 1, 29 + lwz r11, (swapper_pg_dir-PAGE_OFFSET)@l(r11) /* Get the level 1 entry */ + + /* We have a pte table, so load fetch the pte from the table. + */ + /* Extract level 2 index */ + rlwinm r10, r10, 32 - (PAGE_SHIFT - 2), 32 - PAGE_SHIFT, 29 +#ifdef CONFIG_HUGETLB_PAGE + mtcr r11 + bt- 28, 10f /* bit 28 = Large page (8M) */ + bt- 29, 20f /* bit 29 = Large page (8M or 512k) */ +#endif + rlwimi r10, r11, 0, 0, 32 - PAGE_SHIFT - 1 /* Add level 2 base */ + lwz r10, 0(r10) /* Get the pte */ +4: + mtcr r12 + + /* 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, _PAGE_GUARDED + mtspr SPRN_MD_TWC, r11 + + /* Both _PAGE_ACCESSED and _PAGE_PRESENT has to be set. + * We also need to know if the insn is a load/store, so: + * Clear _PAGE_PRESENT and load that which will + * trap into DTLB Error with store bit set accordinly. + */ + /* PRESENT=0x1, ACCESSED=0x20 + * r11 = ((r10 & PRESENT) & ((r10 & ACCESSED) >> 5)); + * r10 = (r10 & ~PRESENT) | r11; + */ + rlwinm r11, r10, 32-7, _PAGE_PRESENT + and r11, r11, r10 + rlwimi r10, r11, 0, _PAGE_PRESENT + /* 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 */ + mtspr SPRN_DAR, r11 /* Tag DAR */ +_ENTRY(dtlb_miss_exit_1) + mfspr r10, SPRN_SPRG_SCRATCH0 + mfspr r11, SPRN_SPRG_SCRATCH1 + mfspr r12, SPRN_SPRG_SCRATCH2 + rfi +#ifdef CONFIG_PERF_EVENTS +_ENTRY(dtlb_miss_perf) + lis r10, (dtlb_miss_counter - PAGE_OFFSET)@ha + lwz r11, (dtlb_miss_counter - PAGE_OFFSET)@l(r10) + addi r11, r11, 1 + stw r11, (dtlb_miss_counter - PAGE_OFFSET)@l(r10) +#endif + mfspr r10, SPRN_SPRG_SCRATCH0 + mfspr r11, SPRN_SPRG_SCRATCH1 + mfspr r12, SPRN_SPRG_SCRATCH2 + rfi + +#ifdef CONFIG_HUGETLB_PAGE +10: /* 8M pages */ + /* Extract level 2 index */ +#ifdef CONFIG_PPC_16K_PAGES + rlwinm r10, r10, 32 - (PAGE_SHIFT_8M - PAGE_SHIFT), 32 + PAGE_SHIFT_8M - (PAGE_SHIFT << 1), 29 + /* Add level 2 base */ + rlwimi r10, r11, 0, 0, 32 + PAGE_SHIFT_8M - (PAGE_SHIFT << 1) - 1 +#else + /* Level 2 base */ + rlwinm r10, r11, 0, ~HUGEPD_SHIFT_MASK +#endif + lwz r10, 0(r10) /* Get the pte */ + b 4b + +20: /* 512k pages */ + /* Extract level 2 index */ + rlwinm r10, r10, 32 - (PAGE_SHIFT_512K - PAGE_SHIFT), 32 + PAGE_SHIFT_512K - (PAGE_SHIFT << 1), 29 + /* Add level 2 base */ + rlwimi r10, r11, 0, 0, 32 + PAGE_SHIFT_512K - (PAGE_SHIFT << 1) - 1 + lwz r10, 0(r10) /* Get the pte */ + b 4b +#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+ 1f + tlbie r4 +itlbie: + /* 0x400 is InstructionAccess exception, needed by bad_page_fault() */ +1: 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: + mtspr SPRN_SPRG_SCRATCH0, r10 + mtspr SPRN_SPRG_SCRATCH1, r11 + mfcr r10 + + mfspr r11, SPRN_DAR + cmpwi cr0, r11, RPN_PATTERN + beq- FixupDAR /* must be a buggy dcbX, icbi insn. */ +DARFixed:/* Return from dcbx instruction bug workaround */ + EXCEPTION_PROLOG_1 + EXCEPTION_PROLOG_2 + mfspr r5,SPRN_DSISR + stw r5,_DSISR(r11) + mfspr r4,SPRN_DAR + andis. r10,r5,DSISR_NOHPTE@h + beq+ 1f + tlbie r4 +dtlbie: +1: li r10,RPN_PATTERN + mtspr SPRN_DAR,r10 /* Tag DAR, to be used in DTLB Error */ + /* 0x300 is DataAccess exception, needed by bad_page_fault() */ + EXC_XFER_LITE(0x300, handle_page_fault) + + 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. + */ + . = 0x1c00 +DataBreakpoint: + mtspr SPRN_SPRG_SCRATCH0, r10 + mtspr SPRN_SPRG_SCRATCH1, r11 + mfcr r10 + mfspr r11, SPRN_SRR0 + cmplwi cr0, r11, (dtlbie - PAGE_OFFSET)@l + cmplwi cr7, r11, (itlbie - PAGE_OFFSET)@l + beq- cr0, 11f + beq- cr7, 11f + EXCEPTION_PROLOG_1 + EXCEPTION_PROLOG_2 + addi r3,r1,STACK_FRAME_OVERHEAD + mfspr r4,SPRN_BAR + stw r4,_DAR(r11) + mfspr r5,SPRN_DSISR + EXC_XFER_EE(0x1c00, do_break) +11: + mtcr r10 + mfspr r10, SPRN_SPRG_SCRATCH0 + mfspr r11, SPRN_SPRG_SCRATCH1 + rfi + +#ifdef CONFIG_PERF_EVENTS + . = 0x1d00 +InstructionBreakpoint: + mtspr SPRN_SPRG_SCRATCH0, r10 + mtspr SPRN_SPRG_SCRATCH1, r11 + lis r10, (instruction_counter - PAGE_OFFSET)@ha + lwz r11, (instruction_counter - PAGE_OFFSET)@l(r10) + addi r11, r11, -1 + stw r11, (instruction_counter - PAGE_OFFSET)@l(r10) + lis r10, 0xffff + ori r10, r10, 0x01 + mtspr SPRN_COUNTA, r10 + mfspr r10, SPRN_SPRG_SCRATCH0 + mfspr r11, SPRN_SPRG_SCRATCH1 + rfi +#else + EXCEPTION(0x1d00, Trap_1d, unknown_exception, EXC_XFER_EE) +#endif + EXCEPTION(0x1e00, Trap_1e, unknown_exception, EXC_XFER_EE) + EXCEPTION(0x1f00, Trap_1f, unknown_exception, EXC_XFER_EE) + + . = 0x2000 + +/* + * Bottom part of DataStoreTLBMiss handlers for IMMR area and linear RAM. + * not enough space in the DataStoreTLBMiss area. + */ +DTLBMissIMMR: + mtcr r12 + /* Set 512k byte guarded page and mark it valid */ + li r10, MD_PS512K | MD_GUARDED | MD_SVALID + mtspr SPRN_MD_TWC, r10 + mfspr r10, SPRN_IMMR /* Get current IMMR */ + rlwinm r10, r10, 0, 0xfff80000 /* Get 512 kbytes boundary */ + ori r10, r10, 0xf0 | MD_SPS16K | _PAGE_PRIVILEGED | _PAGE_DIRTY | \ + _PAGE_PRESENT | _PAGE_NO_CACHE + mtspr SPRN_MD_RPN, r10 /* Update TLB entry */ + + li r11, RPN_PATTERN + mtspr SPRN_DAR, r11 /* Tag DAR */ +_ENTRY(dtlb_miss_exit_2) + mfspr r10, SPRN_SPRG_SCRATCH0 + mfspr r11, SPRN_SPRG_SCRATCH1 + mfspr r12, SPRN_SPRG_SCRATCH2 + rfi + +DTLBMissLinear: + mtcr r12 + /* Set 8M byte page and mark it valid */ + li r11, MD_PS8MEG | MD_SVALID + mtspr SPRN_MD_TWC, r11 + rlwinm r10, r10, 0, 0x0f800000 /* 8xx supports max 256Mb RAM */ + ori r10, r10, 0xf0 | MD_SPS16K | _PAGE_PRIVILEGED | _PAGE_DIRTY | \ + _PAGE_PRESENT + mtspr SPRN_MD_RPN, r10 /* Update TLB entry */ + + li r11, RPN_PATTERN + mtspr SPRN_DAR, r11 /* Tag DAR */ +_ENTRY(dtlb_miss_exit_3) + mfspr r10, SPRN_SPRG_SCRATCH0 + mfspr r11, SPRN_SPRG_SCRATCH1 + mfspr r12, SPRN_SPRG_SCRATCH2 + rfi + +#ifndef CONFIG_PIN_TLB_TEXT +ITLBMissLinear: + mtcr r12 + /* Set 8M byte page and mark it valid */ + li r11, MI_PS8MEG | MI_SVALID + mtspr SPRN_MI_TWC, r11 + rlwinm r10, r10, 0, 0x0f800000 /* 8xx supports max 256Mb RAM */ + ori r10, r10, 0xf0 | MI_SPS16K | _PAGE_PRIVILEGED | _PAGE_DIRTY | \ + _PAGE_PRESENT + mtspr SPRN_MI_RPN, r10 /* Update TLB entry */ + +_ENTRY(itlb_miss_exit_2) + mfspr r10, SPRN_SPRG_SCRATCH0 + mfspr r11, SPRN_SPRG_SCRATCH1 + mfspr r12, SPRN_SPRG_SCRATCH2 + rfi +#endif + +/* 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. + */ + /* define if you don't want to use self modifying code */ +#define NO_SELF_MODIFYING_CODE +FixupDAR:/* Entry point for dcbx workaround. */ + mtspr SPRN_SPRG_SCRATCH2, r10 + /* fetch instruction from memory. */ + mfspr r10, SPRN_SRR0 + rlwinm r11, r10, 16, 0xfff8 + cmpli cr0, r11, PAGE_OFFSET@h + mfspr r11, SPRN_M_TW /* Get level 1 table */ + blt+ 3f + rlwinm r11, r10, 16, 0xfff8 +_ENTRY(FixupDAR_cmp) + cmpli cr7, r11, (PAGE_OFFSET + 0x1800000)@h + /* create physical page address from effective address */ + tophys(r11, r10) + blt- cr7, 201f + lis r11, (swapper_pg_dir-PAGE_OFFSET)@ha + /* Insert level 1 index */ +3: rlwimi r11, r10, 32 - ((PAGE_SHIFT - 2) << 1), (PAGE_SHIFT - 2) << 1, 29 + lwz r11, (swapper_pg_dir-PAGE_OFFSET)@l(r11) /* Get the level 1 entry */ + mtcr r11 + bt 28,200f /* bit 28 = Large page (8M) */ + bt 29,202f /* bit 29 = Large page (8M or 512K) */ + rlwinm r11, r11,0,0,19 /* Extract page descriptor page address */ + /* Insert level 2 index */ + rlwimi r11, r10, 32 - (PAGE_SHIFT - 2), 32 - PAGE_SHIFT, 29 + lwz r11, 0(r11) /* Get the pte */ + /* 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 cr0, r10, 2028 /* Is dcbz? */ + beq+ 142f + cmpwi cr0, r10, 940 /* Is dcbi? */ + beq+ 142f + cmpwi cr0, r10, 108 /* Is dcbst? */ + beq+ 144f /* Fix up store bit! */ + cmpwi cr0, r10, 172 /* Is dcbf? */ + beq+ 142f + cmpwi cr0, r10, 1964 /* Is icbi? */ + beq+ 142f +141: mfspr r10,SPRN_SPRG_SCRATCH2 + b DARFixed /* Nope, go back to normal TLB processing */ + + /* concat physical page address(r11) and page offset(r10) */ +200: +#ifdef CONFIG_PPC_16K_PAGES + rlwinm r11, r11, 0, 0, 32 + PAGE_SHIFT_8M - (PAGE_SHIFT << 1) - 1 + rlwimi r11, r10, 32 - (PAGE_SHIFT_8M - 2), 32 + PAGE_SHIFT_8M - (PAGE_SHIFT << 1), 29 +#else + rlwinm r11, r10, 0, ~HUGEPD_SHIFT_MASK +#endif + lwz r11, 0(r11) /* Get the pte */ + /* concat physical page address(r11) and page offset(r10) */ + rlwimi r11, r10, 0, 32 - PAGE_SHIFT_8M, 31 + b 201b + +202: + rlwinm r11, r11, 0, 0, 32 + PAGE_SHIFT_512K - (PAGE_SHIFT << 1) - 1 + rlwimi r11, r10, 32 - (PAGE_SHIFT_512K - 2), 32 + PAGE_SHIFT_512K - (PAGE_SHIFT << 1), 29 + lwz r11, 0(r11) /* Get the pte */ + /* concat physical page address(r11) and page offset(r10) */ + rlwimi r11, r10, 0, 32 - PAGE_SHIFT_512K, 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. */ +#ifndef NO_SELF_MODIFYING_CODE + andis. r10,r11,0x1f /* test if reg RA is r0 */ + li r10,modified_instr@l + dcbtst r0,r10 /* touch for store */ + rlwinm r11,r11,0,0,20 /* Zero lower 10 bits */ + oris r11,r11,640 /* Transform instr. to a "add r10,RA,RB" */ + ori r11,r11,532 + stw r11,0(r10) /* store add/and instruction */ + dcbf 0,r10 /* flush new instr. to memory. */ + icbi 0,r10 /* invalidate instr. cache line */ + mfspr r11, SPRN_SPRG_SCRATCH1 /* restore r11 */ + mfspr r10, SPRN_SPRG_SCRATCH0 /* restore r10 */ + isync /* Wait until new instr is loaded from memory */ +modified_instr: + .space 4 /* this is where the add instr. is stored */ + bne+ 143f + subf r10,r0,r10 /* r10=r10-r0, only if reg RA is r0 */ +143: mtdar r10 /* store faulting EA in DAR */ + mfspr r10,SPRN_SPRG_SCRATCH2 + b DARFixed /* Go back to normal TLB handling */ +#else + 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 */ + beq 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 */ + mtdar r10 /* save fault EA to DAR */ + mfspr r10,SPRN_SPRG_SCRATCH2 + 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 +#endif + +/* + * 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 + li r0,0 + stwu r0,THREAD_SIZE-STACK_FRAME_OVERHEAD(r1) + + lis r6, swapper_pg_dir@ha + tophys(r6,r6) + mtspr SPRN_M_TW, r6 + + bl early_init /* We have to do this with MMU on */ + +/* + * Decide what sort of machine this is and initialize the MMU. + */ + 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: + 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_RESETVAL@h +#ifndef CONFIG_8xx_COPYBACK + oris r10, r10, MD_WTDEF@h +#endif + mtspr SPRN_MD_CTR, r10 /* remove PINNED DTLB entries */ + + tlbia /* Invalidate all TLB entries */ +#ifdef CONFIG_PIN_TLB_TEXT + lis r8, MI_RSV4I@h + ori r8, r8, 0x1c00 + + mtspr SPRN_MI_CTR, r8 /* Set instruction MMU control */ +#endif + +#ifdef CONFIG_PIN_TLB_DATA + oris r10, r10, MD_RSV4I@h + mtspr SPRN_MD_CTR, r10 /* Set data TLB control */ +#endif + + /* Now map the lower 8 Meg into the ITLB. */ + lis r8, KERNELBASE@h /* Create vaddr for TLB */ + ori r8, r8, MI_EVALID /* Mark it valid */ + mtspr SPRN_MI_EPN, r8 + li r8, MI_PS8MEG /* Set 8M byte page */ + ori r8, r8, MI_SVALID /* Make it valid */ + mtspr SPRN_MI_TWC, r8 + li r8, MI_BOOTINIT /* Create RPN for address 0 */ + mtspr SPRN_MI_RPN, r8 /* Store TLB entry */ + + 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 a 512k page for the IMMR to get the processor + * internal registers (among other things). + */ +#ifdef CONFIG_PIN_TLB_IMMR + oris r10, r10, MD_RSV4I@h + ori r10, r10, 0x1c00 + mtspr SPRN_MD_CTR, r10 + + mfspr r9, 638 /* Get current IMMR */ + andis. r9, r9, 0xfff8 /* Get 512 kbytes boundary */ + + lis r8, VIRT_IMMR_BASE@h /* Create vaddr for TLB */ + ori r8, r8, MD_EVALID /* Mark it valid */ + mtspr SPRN_MD_EPN, r8 + li r8, MD_PS512K | MD_GUARDED /* Set 512k 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 +#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 + /* 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 + + +/* + * 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). + */ +abatron_pteptrs: + .space 8 + +#ifdef CONFIG_PERF_EVENTS + .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 |