traps.c

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/* MN10300 Exception handling
 *
 * Copyright (C) 2007 Matsushita Electric Industrial Co., Ltd.
 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
 * Modified by David Howells ([email protected])
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public Licence
 * as published by the Free Software Foundation; either version
 * 2 of the Licence, or (at your option) any later version.
 */
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/timer.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <linux/kallsyms.h>
#include <linux/pci.h>
#include <linux/kdebug.h>
#include <linux/bug.h>
#include <linux/irq.h>
#include <linux/export.h>
#include <asm/processor.h>
#include <linux/uaccess.h>
#include <asm/io.h>
#include <linux/atomic.h>
#include <asm/smp.h>
#include <asm/pgalloc.h>
#include <asm/cacheflush.h>
#include <asm/cpu-regs.h>
#include <asm/busctl-regs.h>
#include <unit/leds.h>
#include <asm/fpu.h>
#include <asm/sections.h>
#include <asm/debugger.h>
#include "internal.h"

#if (CONFIG_INTERRUPT_VECTOR_BASE & 0xffffff)
#error "INTERRUPT_VECTOR_BASE not aligned to 16MiB boundary!"
#endif

int kstack_depth_to_print = 24;

spinlock_t die_lock = __SPIN_LOCK_UNLOCKED(die_lock);

struct exception_to_signal_map {
    u8  signo;
    u32 si_code;
};

static const struct exception_to_signal_map exception_to_signal_map[256] = {
    /* MMU exceptions */
    [EXCEP_ITLBMISS >> 3]   = { 0, 0 },
    [EXCEP_DTLBMISS >> 3]   = { 0, 0 },
    [EXCEP_IAERROR >> 3]    = { 0, 0 },
    [EXCEP_DAERROR >> 3]    = { 0, 0 },

    /* system exceptions */
    [EXCEP_TRAP >> 3]   = { SIGTRAP,    TRAP_BRKPT },
    [EXCEP_ISTEP >> 3]  = { SIGTRAP,    TRAP_TRACE },   /* Monitor */
    [EXCEP_IBREAK >> 3] = { SIGTRAP,    TRAP_HWBKPT },  /* Monitor */
    [EXCEP_OBREAK >> 3] = { SIGTRAP,    TRAP_HWBKPT },  /* Monitor */
    [EXCEP_PRIVINS >> 3]    = { SIGILL, ILL_PRVOPC },
    [EXCEP_UNIMPINS >> 3]   = { SIGILL, ILL_ILLOPC },
    [EXCEP_UNIMPEXINS >> 3] = { SIGILL, ILL_ILLOPC },
    [EXCEP_MEMERR >> 3] = { SIGSEGV,    SEGV_ACCERR },
    [EXCEP_MISALIGN >> 3]   = { SIGBUS, BUS_ADRALN },
    [EXCEP_BUSERROR >> 3]   = { SIGBUS, BUS_ADRERR },
    [EXCEP_ILLINSACC >> 3]  = { SIGSEGV,    SEGV_ACCERR },
    [EXCEP_ILLDATACC >> 3]  = { SIGSEGV,    SEGV_ACCERR },
    [EXCEP_IOINSACC >> 3]   = { SIGSEGV,    SEGV_ACCERR },
    [EXCEP_PRIVINSACC >> 3] = { SIGSEGV,    SEGV_ACCERR }, /* userspace */
    [EXCEP_PRIVDATACC >> 3] = { SIGSEGV,    SEGV_ACCERR }, /* userspace */
    [EXCEP_DATINSACC >> 3]  = { SIGSEGV,    SEGV_ACCERR },
    [EXCEP_DOUBLE_FAULT >> 3] = { SIGILL,   ILL_BADSTK },

    /* FPU exceptions */
    [EXCEP_FPU_DISABLED >> 3] = { SIGILL,   ILL_COPROC },
    [EXCEP_FPU_UNIMPINS >> 3] = { SIGILL,   ILL_COPROC },
    [EXCEP_FPU_OPERATION >> 3] = { SIGFPE,  FPE_INTDIV },

    /* interrupts */
    [EXCEP_WDT >> 3]    = { SIGALRM,    0 },
    [EXCEP_NMI >> 3]    = { SIGQUIT,    0 },
    [EXCEP_IRQ_LEVEL0 >> 3] = { SIGINT, 0 },
    [EXCEP_IRQ_LEVEL1 >> 3] = { 0, 0 },
    [EXCEP_IRQ_LEVEL2 >> 3] = { 0, 0 },
    [EXCEP_IRQ_LEVEL3 >> 3] = { 0, 0 },
    [EXCEP_IRQ_LEVEL4 >> 3] = { 0, 0 },
    [EXCEP_IRQ_LEVEL5 >> 3] = { 0, 0 },
    [EXCEP_IRQ_LEVEL6 >> 3] = { 0, 0 },

    /* system calls */
    [EXCEP_SYSCALL0 >> 3]   = { 0, 0 },
    [EXCEP_SYSCALL1 >> 3]   = { SIGILL, ILL_ILLTRP },
    [EXCEP_SYSCALL2 >> 3]   = { SIGILL, ILL_ILLTRP },
    [EXCEP_SYSCALL3 >> 3]   = { SIGILL, ILL_ILLTRP },
    [EXCEP_SYSCALL4 >> 3]   = { SIGILL, ILL_ILLTRP },
    [EXCEP_SYSCALL5 >> 3]   = { SIGILL, ILL_ILLTRP },
    [EXCEP_SYSCALL6 >> 3]   = { SIGILL, ILL_ILLTRP },
    [EXCEP_SYSCALL7 >> 3]   = { SIGILL, ILL_ILLTRP },
    [EXCEP_SYSCALL8 >> 3]   = { SIGILL, ILL_ILLTRP },
    [EXCEP_SYSCALL9 >> 3]   = { SIGILL, ILL_ILLTRP },
    [EXCEP_SYSCALL10 >> 3]  = { SIGILL, ILL_ILLTRP },
    [EXCEP_SYSCALL11 >> 3]  = { SIGILL, ILL_ILLTRP },
    [EXCEP_SYSCALL12 >> 3]  = { SIGILL, ILL_ILLTRP },
    [EXCEP_SYSCALL13 >> 3]  = { SIGILL, ILL_ILLTRP },
    [EXCEP_SYSCALL14 >> 3]  = { SIGILL, ILL_ILLTRP },
    [EXCEP_SYSCALL15 >> 3]  = { SIGABRT,    0 },
};

/*
 * Handle kernel exceptions.
 *
 * See if there's a fixup handler we can force a jump to when an exception
 * happens due to something kernel code did
 */
int die_if_no_fixup(const char *str, struct pt_regs *regs,
            enum exception_code code)
{
    u8 opcode;
    int signo, si_code;

    if (user_mode(regs))
        return 0;

    peripheral_leds_display_exception(code);

    signo = exception_to_signal_map[code >> 3].signo;
    si_code = exception_to_signal_map[code >> 3].si_code;

    switch (code) {
        /* see if we can fixup the kernel accessing memory */
    case EXCEP_ITLBMISS:
    case EXCEP_DTLBMISS:
    case EXCEP_IAERROR:
    case EXCEP_DAERROR:
    case EXCEP_MEMERR:
    case EXCEP_MISALIGN:
    case EXCEP_BUSERROR:
    case EXCEP_ILLDATACC:
    case EXCEP_IOINSACC:
    case EXCEP_PRIVINSACC:
    case EXCEP_PRIVDATACC:
    case EXCEP_DATINSACC:
        if (fixup_exception(regs))
            return 1;
        break;

    case EXCEP_TRAP:
    case EXCEP_UNIMPINS:
        if (probe_kernel_read(&opcode, (u8 *)regs->pc, 1) < 0)
            break;
        if (opcode == 0xff) {
            if (notify_die(DIE_BREAKPOINT, str, regs, code, 0, 0))
                return 1;
            if (at_debugger_breakpoint(regs))
                regs->pc++;
            signo = SIGTRAP;
            si_code = TRAP_BRKPT;
        }
        break;

    case EXCEP_SYSCALL1 ... EXCEP_SYSCALL14:
        /* syscall return addr is _after_ the instruction */
        regs->pc -= 2;
        break;

    case EXCEP_SYSCALL15:
        if (report_bug(regs->pc, regs) == BUG_TRAP_TYPE_WARN)
            return 1;

        /* syscall return addr is _after_ the instruction */
        regs->pc -= 2;
        break;

    default:
        break;
    }

    if (debugger_intercept(code, signo, si_code, regs) == 0)
        return 1;

    if (notify_die(DIE_GPF, str, regs, code, 0, 0))
        return 1;

    /* make the process die as the last resort */
    die(str, regs, code);
}

/*
 * General exception handler
 */
asmlinkage void handle_exception(struct pt_regs *regs, u32 intcode)
{
    siginfo_t info;

    /* deal with kernel exceptions here */
    if (die_if_no_fixup(NULL, regs, intcode))
        return;

    /* otherwise it's a userspace exception */
    info.si_signo = exception_to_signal_map[intcode >> 3].signo;
    info.si_code = exception_to_signal_map[intcode >> 3].si_code;
    info.si_errno = 0;
    info.si_addr = (void *) regs->pc;
    force_sig_info(info.si_signo, &info, current);
}

/*
 * handle NMI
 */
asmlinkage void nmi(struct pt_regs *regs, enum exception_code code)
{
    /* see if gdbstub wants to deal with it */
    if (debugger_intercept(code, SIGQUIT, 0, regs))
        return;

    printk(KERN_WARNING "--- Register Dump ---\n");
    show_registers(regs);
    printk(KERN_WARNING "---------------------\n");
}

/*
 * show a stack trace from the specified stack pointer
 */
void show_trace(unsigned long *sp)
{
    unsigned long bottom, stack, addr, fp, raslot;

    printk(KERN_EMERG "\nCall Trace:\n");

    //stack = (unsigned long)sp;
    asm("mov sp,%0" : "=a"(stack));
    asm("mov a3,%0" : "=r"(fp));

    raslot = ULONG_MAX;
    bottom = (stack + THREAD_SIZE) & ~(THREAD_SIZE - 1);
    for (; stack < bottom; stack += sizeof(addr)) {
        addr = *(unsigned long *)stack;
        if (stack == fp) {
            if (addr > stack && addr < bottom) {
                fp = addr;
                raslot = stack + sizeof(addr);
                continue;
            }
            fp = 0;
            raslot = ULONG_MAX;
        }

        if (__kernel_text_address(addr)) {
            printk(" [<%08lx>]", addr);
            if (stack >= raslot)
                raslot = ULONG_MAX;
            else
                printk(" ?");
            print_symbol(" %s", addr);
            printk("\n");
        }
    }

    printk("\n");
}

/*
 * show the raw stack from the specified stack pointer
 */
void show_stack(struct task_struct *task, unsigned long *sp)
{
    unsigned long *stack;
    int i;

    if (!sp)
        sp = (unsigned long *) &sp;

    stack = sp;
    printk(KERN_EMERG "Stack:");
    for (i = 0; i < kstack_depth_to_print; i++) {
        if (((long) stack & (THREAD_SIZE - 1)) == 0)
            break;
        if ((i % 8) == 0)
            printk(KERN_EMERG "  ");
        printk("%08lx ", *stack++);
    }

    show_trace(sp);
}

/*
 * the architecture-independent dump_stack generator
 */
void dump_stack(void)
{
    unsigned long stack;

    show_stack(current, &stack);
}
EXPORT_SYMBOL(dump_stack);

/*
 * dump the register file in the specified exception frame
 */
void show_registers_only(struct pt_regs *regs)
{
    unsigned long ssp;

    ssp = (unsigned long) regs + sizeof(*regs);

    printk(KERN_EMERG "PC:  %08lx EPSW:  %08lx  SSP: %08lx mode: %s\n",
           regs->pc, regs->epsw, ssp, user_mode(regs) ? "User" : "Super");
    printk(KERN_EMERG "d0:  %08lx   d1:  %08lx   d2: %08lx   d3: %08lx\n",
           regs->d0, regs->d1, regs->d2, regs->d3);
    printk(KERN_EMERG "a0:  %08lx   a1:  %08lx   a2: %08lx   a3: %08lx\n",
           regs->a0, regs->a1, regs->a2, regs->a3);
    printk(KERN_EMERG "e0:  %08lx   e1:  %08lx   e2: %08lx   e3: %08lx\n",
           regs->e0, regs->e1, regs->e2, regs->e3);
    printk(KERN_EMERG "e4:  %08lx   e5:  %08lx   e6: %08lx   e7: %08lx\n",
           regs->e4, regs->e5, regs->e6, regs->e7);
    printk(KERN_EMERG "lar: %08lx   lir: %08lx  mdr: %08lx  usp: %08lx\n",
           regs->lar, regs->lir, regs->mdr, regs->sp);
    printk(KERN_EMERG "cvf: %08lx   crl: %08lx  crh: %08lx  drq: %08lx\n",
           regs->mcvf, regs->mcrl, regs->mcrh, regs->mdrq);
    printk(KERN_EMERG "threadinfo=%p task=%p)\n",
           current_thread_info(), current);

    if ((unsigned long) current >= PAGE_OFFSET &&
        (unsigned long) current < (unsigned long)high_memory)
        printk(KERN_EMERG "Process %s (pid: %d)\n",
               current->comm, current->pid);

#ifdef CONFIG_SMP
    printk(KERN_EMERG "CPUID:  %08x\n", CPUID);
#endif
    printk(KERN_EMERG "CPUP:   %04hx\n", CPUP);
    printk(KERN_EMERG "TBR:    %08x\n", TBR);
    printk(KERN_EMERG "DEAR:   %08x\n", DEAR);
    printk(KERN_EMERG "sISR:   %08x\n", sISR);
    printk(KERN_EMERG "NMICR:  %04hx\n", NMICR);
    printk(KERN_EMERG "BCBERR: %08x\n", BCBERR);
    printk(KERN_EMERG "BCBEAR: %08x\n", BCBEAR);
    printk(KERN_EMERG "MMUFCR: %08x\n", MMUFCR);
    printk(KERN_EMERG "IPTEU : %08x  IPTEL2: %08x\n", IPTEU, IPTEL2);
    printk(KERN_EMERG "DPTEU:  %08x  DPTEL2: %08x\n", DPTEU, DPTEL2);
}

/*
 * dump the registers and the stack
 */
void show_registers(struct pt_regs *regs)
{
    unsigned long sp;
    int i;

    show_registers_only(regs);

    if (!user_mode(regs))
        sp = (unsigned long) regs + sizeof(*regs);
    else
        sp = regs->sp;

    /* when in-kernel, we also print out the stack and code at the
     * time of the fault..
     */
    if (!user_mode(regs)) {
        printk(KERN_EMERG "\n");
        show_stack(current, (unsigned long *) sp);

#if 0
        printk(KERN_EMERG "\nCode: ");
        if (regs->pc < PAGE_OFFSET)
            goto bad;

        for (i = 0; i < 20; i++) {
            unsigned char c;
            if (__get_user(c, &((unsigned char *) regs->pc)[i]))
                goto bad;
            printk("%02x ", c);
        }
#else
        i = 0;
#endif
    }

    printk("\n");
    return;

#if 0
bad:
    printk(KERN_EMERG " Bad PC value.");
    break;
#endif
}

/*
 *
 */
void show_trace_task(struct task_struct *tsk)
{
    unsigned long sp = tsk->thread.sp;

    /* User space on another CPU? */
    if ((sp ^ (unsigned long) tsk) & (PAGE_MASK << 1))
        return;

    show_trace((unsigned long *) sp);
}

/*
 * note the untimely death of part of the kernel
 */
void die(const char *str, struct pt_regs *regs, enum exception_code code)
{
    console_verbose();
    spin_lock_irq(&die_lock);
    printk(KERN_EMERG "\n%s: %04x\n",
           str, code & 0xffff);
    show_registers(regs);

    if (regs->pc >= 0x02000000 && regs->pc < 0x04000000 &&
        (regs->epsw & (EPSW_IM | EPSW_IE)) != (EPSW_IM | EPSW_IE)) {
        printk(KERN_EMERG "Exception in usermode interrupt handler\n");
        printk(KERN_EMERG "\nPlease connect to kernel debugger !!\n");
        asm volatile ("0: bra 0b");
    }

    spin_unlock_irq(&die_lock);
    do_exit(SIGSEGV);
}

/*
 * display the register file when the stack pointer gets clobbered
 */
asmlinkage void do_double_fault(struct pt_regs *regs)
{
    struct task_struct *tsk = current;

    strcpy(tsk->comm, "emergency tsk");
    tsk->pid = 0;
    console_verbose();
    printk(KERN_EMERG "--- double fault ---\n");
    show_registers(regs);
}

/*
 * asynchronous bus error (external, usually I/O DMA)
 */
asmlinkage void io_bus_error(u32 bcberr, u32 bcbear, struct pt_regs *regs)
{
    console_verbose();

    printk(KERN_EMERG "Asynchronous I/O Bus Error\n");
    printk(KERN_EMERG "==========================\n");

    if (bcberr & BCBERR_BEME)
        printk(KERN_EMERG "- Multiple recorded errors\n");

    printk(KERN_EMERG "- Faulting Buses:%s%s%s\n",
           bcberr & BCBERR_BEMR_CI  ? " CPU-Ins-Fetch" : "",
           bcberr & BCBERR_BEMR_CD  ? " CPU-Data" : "",
           bcberr & BCBERR_BEMR_DMA ? " DMA" : "");

    printk(KERN_EMERG "- %s %s access made to %s at address %08x\n",
           bcberr & BCBERR_BEBST ? "Burst" : "Single",
           bcberr & BCBERR_BERW ? "Read" : "Write",
           bcberr & BCBERR_BESB_MON  ? "Monitor Space" :
           bcberr & BCBERR_BESB_IO   ? "Internal CPU I/O Space" :
           bcberr & BCBERR_BESB_EX   ? "External I/O Bus" :
           bcberr & BCBERR_BESB_OPEX ? "External Memory Bus" :
           "On Chip Memory",
           bcbear
           );

    printk(KERN_EMERG "- Detected by the %s\n",
           bcberr&BCBERR_BESD ? "Bus Control Unit" : "Slave Bus");

#ifdef CONFIG_PCI
#define BRIDGEREGB(X) (*(volatile __u8  *)(0xBE040000 + (X)))
#define BRIDGEREGW(X) (*(volatile __u16 *)(0xBE040000 + (X)))
#define BRIDGEREGL(X) (*(volatile __u32 *)(0xBE040000 + (X)))

    printk(KERN_EMERG "- PCI Memory Paging Reg:         %08x\n",
           *(volatile __u32 *) (0xBFFFFFF4));
    printk(KERN_EMERG "- PCI Bridge Base Address 0:     %08x\n",
           BRIDGEREGL(PCI_BASE_ADDRESS_0));
    printk(KERN_EMERG "- PCI Bridge AMPCI Base Address: %08x\n",
           BRIDGEREGL(0x48));
    printk(KERN_EMERG "- PCI Bridge Command:                %04hx\n",
           BRIDGEREGW(PCI_COMMAND));
    printk(KERN_EMERG "- PCI Bridge Status:                 %04hx\n",
           BRIDGEREGW(PCI_STATUS));
    printk(KERN_EMERG "- PCI Bridge Int Status:         %08hx\n",
           BRIDGEREGL(0x4c));
#endif

    printk(KERN_EMERG "\n");
    show_registers(regs);

    panic("Halted due to asynchronous I/O Bus Error\n");
}

/*
 * handle an exception for which a handler has not yet been installed
 */
asmlinkage void uninitialised_exception(struct pt_regs *regs,
                    enum exception_code code)
{

    /* see if gdbstub wants to deal with it */
    if (debugger_intercept(code, SIGSYS, 0, regs) == 0)
        return;

    peripheral_leds_display_exception(code);
    printk(KERN_EMERG "Uninitialised Exception 0x%04x\n", code & 0xFFFF);
    show_registers(regs);

    for (;;)
        continue;
}

/*
 * set an interrupt stub to jump to a handler
 * ! NOTE: this does *not* flush the caches
 */
void __init __set_intr_stub(enum exception_code code, void *handler)
{
    unsigned long addr;
    u8 *vector = (u8 *)(CONFIG_INTERRUPT_VECTOR_BASE + code);

    addr = (unsigned long) handler - (unsigned long) vector;
    vector[0] = 0xdc;       /* JMP handler */
    vector[1] = addr;
    vector[2] = addr >> 8;
    vector[3] = addr >> 16;
    vector[4] = addr >> 24;
    vector[5] = 0xcb;
    vector[6] = 0xcb;
    vector[7] = 0xcb;
}

/*
 * set an interrupt stub to jump to a handler
 */
void __init set_intr_stub(enum exception_code code, void *handler)
{
    unsigned long addr;
    u8 *vector = (u8 *)(CONFIG_INTERRUPT_VECTOR_BASE + code);
    unsigned long flags;

    addr = (unsigned long) handler - (unsigned long) vector;

    flags = arch_local_cli_save();

    vector[0] = 0xdc;       /* JMP handler */
    vector[1] = addr;
    vector[2] = addr >> 8;
    vector[3] = addr >> 16;
    vector[4] = addr >> 24;
    vector[5] = 0xcb;
    vector[6] = 0xcb;
    vector[7] = 0xcb;

    arch_local_irq_restore(flags);

#ifndef CONFIG_MN10300_CACHE_SNOOP
    mn10300_dcache_flush_inv();
    mn10300_icache_inv();
#endif
}

/*
 * initialise the exception table
 */
void __init trap_init(void)
{
    set_excp_vector(EXCEP_TRAP,     handle_exception);
    set_excp_vector(EXCEP_ISTEP,        handle_exception);
    set_excp_vector(EXCEP_IBREAK,       handle_exception);
    set_excp_vector(EXCEP_OBREAK,       handle_exception);

    set_excp_vector(EXCEP_PRIVINS,      handle_exception);
    set_excp_vector(EXCEP_UNIMPINS,     handle_exception);
    set_excp_vector(EXCEP_UNIMPEXINS,   handle_exception);
    set_excp_vector(EXCEP_MEMERR,       handle_exception);
    set_excp_vector(EXCEP_MISALIGN,     misalignment);
    set_excp_vector(EXCEP_BUSERROR,     handle_exception);
    set_excp_vector(EXCEP_ILLINSACC,    handle_exception);
    set_excp_vector(EXCEP_ILLDATACC,    handle_exception);
    set_excp_vector(EXCEP_IOINSACC,     handle_exception);
    set_excp_vector(EXCEP_PRIVINSACC,   handle_exception);
    set_excp_vector(EXCEP_PRIVDATACC,   handle_exception);
    set_excp_vector(EXCEP_DATINSACC,    handle_exception);
    set_excp_vector(EXCEP_FPU_UNIMPINS, handle_exception);
    set_excp_vector(EXCEP_FPU_OPERATION,    fpu_exception);

    set_excp_vector(EXCEP_NMI,      nmi);

    set_excp_vector(EXCEP_SYSCALL1,     handle_exception);
    set_excp_vector(EXCEP_SYSCALL2,     handle_exception);
    set_excp_vector(EXCEP_SYSCALL3,     handle_exception);
    set_excp_vector(EXCEP_SYSCALL4,     handle_exception);
    set_excp_vector(EXCEP_SYSCALL5,     handle_exception);
    set_excp_vector(EXCEP_SYSCALL6,     handle_exception);
    set_excp_vector(EXCEP_SYSCALL7,     handle_exception);
    set_excp_vector(EXCEP_SYSCALL8,     handle_exception);
    set_excp_vector(EXCEP_SYSCALL9,     handle_exception);
    set_excp_vector(EXCEP_SYSCALL10,    handle_exception);
    set_excp_vector(EXCEP_SYSCALL11,    handle_exception);
    set_excp_vector(EXCEP_SYSCALL12,    handle_exception);
    set_excp_vector(EXCEP_SYSCALL13,    handle_exception);
    set_excp_vector(EXCEP_SYSCALL14,    handle_exception);
    set_excp_vector(EXCEP_SYSCALL15,    handle_exception);
}

/*
 * determine if a program counter value is a valid bug address
 */
int is_valid_bugaddr(unsigned long pc)
{
    return pc >= PAGE_OFFSET;
}