[deliverable/linux.git] / arch / ppc / kernel / traps.c

/*
 *  arch/ppc/kernel/traps.c
 *
 *  Copyright (C) 1995-1996  Gary Thomas (gdt@linuxppc.org)
 *
 *  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.
 *
 *  Modified by Cort Dougan (cort@cs.nmt.edu)
 *  and Paul Mackerras (paulus@cs.anu.edu.au)
 */

/*
 * This file handles the architecture-dependent parts of hardware exceptions
 */

#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/stddef.h>
#include <linux/unistd.h>
#include <linux/ptrace.h>
#include <linux/slab.h>
#include <linux/user.h>
#include <linux/a.out.h>
#include <linux/interrupt.h>
#include <linux/config.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/prctl.h>

#include <asm/pgtable.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/io.h>
#include <asm/reg.h>
#include <asm/xmon.h>
#include <asm/pmc.h>

#ifdef CONFIG_XMON
extern int xmon_bpt(struct pt_regs *regs);
extern int xmon_sstep(struct pt_regs *regs);
extern int xmon_iabr_match(struct pt_regs *regs);
extern int xmon_dabr_match(struct pt_regs *regs);

int (*debugger)(struct pt_regs *regs) = xmon;
int (*debugger_bpt)(struct pt_regs *regs) = xmon_bpt;
int (*debugger_sstep)(struct pt_regs *regs) = xmon_sstep;
int (*debugger_iabr_match)(struct pt_regs *regs) = xmon_iabr_match;
int (*debugger_dabr_match)(struct pt_regs *regs) = xmon_dabr_match;
void (*debugger_fault_handler)(struct pt_regs *regs);
#else
#ifdef CONFIG_KGDB
int (*debugger)(struct pt_regs *regs);
int (*debugger_bpt)(struct pt_regs *regs);
int (*debugger_sstep)(struct pt_regs *regs);
int (*debugger_iabr_match)(struct pt_regs *regs);
int (*debugger_dabr_match)(struct pt_regs *regs);
void (*debugger_fault_handler)(struct pt_regs *regs);
#else
#define debugger(regs)                  do { } while (0)
#define debugger_bpt(regs)              0
#define debugger_sstep(regs)            0
#define debugger_iabr_match(regs)       0
#define debugger_dabr_match(regs)       0
#define debugger_fault_handler          ((void (*)(struct pt_regs *))0)
#endif
#endif

/*
 * Trap & Exception support
 */

DEFINE_SPINLOCK(die_lock);

int die(const char * str, struct pt_regs * fp, long err)
{
        static int die_counter;
        int nl = 0;
        console_verbose();
        spin_lock_irq(&die_lock);
        printk("Oops: %s, sig: %ld [#%d]\n", str, err, ++die_counter);
#ifdef CONFIG_PREEMPT
        printk("PREEMPT ");
        nl = 1;
#endif
#ifdef CONFIG_SMP
        printk("SMP NR_CPUS=%d ", NR_CPUS);
        nl = 1;
#endif
        if (nl)
                printk("\n");
        show_regs(fp);
        spin_unlock_irq(&die_lock);
        /* do_exit() should take care of panic'ing from an interrupt
         * context so we don't handle it here
         */
        do_exit(err);
}

void _exception(int signr, struct pt_regs *regs, int code, unsigned long addr)
{
        siginfo_t info;

        if (!user_mode(regs)) {
                debugger(regs);
                die("Exception in kernel mode", regs, signr);
        }
        info.si_signo = signr;
        info.si_errno = 0;
        info.si_code = code;
        info.si_addr = (void __user *) addr;
        force_sig_info(signr, &info, current);

        /*
         * Init gets no signals that it doesn't have a handler for.
         * That's all very well, but if it has caused a synchronous
         * exception and we ignore the resulting signal, it will just
         * generate the same exception over and over again and we get
         * nowhere.  Better to kill it and let the kernel panic.
         */
        if (current->pid == 1) {
                __sighandler_t handler;

                spin_lock_irq(&current->sighand->siglock);
                handler = current->sighand->action[signr-1].sa.sa_handler;
                spin_unlock_irq(&current->sighand->siglock);
                if (handler == SIG_DFL) {
                        /* init has generated a synchronous exception
                           and it doesn't have a handler for the signal */
                        printk(KERN_CRIT "init has generated signal %d "
                               "but has no handler for it\n", signr);
                        do_exit(signr);
                }
        }
}

/*
 * I/O accesses can cause machine checks on powermacs.
 * Check if the NIP corresponds to the address of a sync
 * instruction for which there is an entry in the exception
 * table.
 * Note that the 601 only takes a machine check on TEA
 * (transfer error ack) signal assertion, and does not
 * set any of the top 16 bits of SRR1.
 *  -- paulus.
 */
static inline int check_io_access(struct pt_regs *regs)
{
#if defined CONFIG_8xx
        unsigned long msr = regs->msr;
        const struct exception_table_entry *entry;
        unsigned int *nip = (unsigned int *)regs->nip;

        if (((msr & 0xffff0000) == 0 || (msr & (0x80000 | 0x40000)))
            && (entry = search_exception_tables(regs->nip)) != NULL) {
                /*
                 * Check that it's a sync instruction, or somewhere
                 * in the twi; isync; nop sequence that inb/inw/inl uses.
                 * As the address is in the exception table
                 * we should be able to read the instr there.
                 * For the debug message, we look at the preceding
                 * load or store.
                 */
                if (*nip == 0x60000000)         /* nop */
                        nip -= 2;
                else if (*nip == 0x4c00012c)    /* isync */
                        --nip;
                /* eieio from I/O string functions */
                else if ((*nip) == 0x7c0006ac || *(nip+1) == 0x7c0006ac)
                        nip += 2;
                if (*nip == 0x7c0004ac || (*nip >> 26) == 3 ||
                        (*(nip+1) >> 26) == 3) {
                        /* sync or twi */
                        unsigned int rb;

                        --nip;
                        rb = (*nip >> 11) & 0x1f;
                        printk(KERN_DEBUG "%s bad port %lx at %p\n",
                               (*nip & 0x100)? "OUT to": "IN from",
                               regs->gpr[rb] - _IO_BASE, nip);
                        regs->msr |= MSR_RI;
                        regs->nip = entry->fixup;
                        return 1;
                }
        }
#endif /* CONFIG_8xx */
        return 0;
}

#if defined(CONFIG_4xx) || defined(CONFIG_BOOKE)
/* On 4xx, the reason for the machine check or program exception
   is in the ESR. */
#define get_reason(regs)        ((regs)->dsisr)
#ifndef CONFIG_FSL_BOOKE
#define get_mc_reason(regs)     ((regs)->dsisr)
#else
#define get_mc_reason(regs)     (mfspr(SPRN_MCSR))
#endif
#define REASON_FP               ESR_FP
#define REASON_ILLEGAL          (ESR_PIL | ESR_PUO)
#define REASON_PRIVILEGED       ESR_PPR
#define REASON_TRAP             ESR_PTR

/* single-step stuff */
#define single_stepping(regs)   (current->thread.dbcr0 & DBCR0_IC)
#define clear_single_step(regs) (current->thread.dbcr0 &= ~DBCR0_IC)

#else
/* On non-4xx, the reason for the machine check or program
   exception is in the MSR. */
#define get_reason(regs)        ((regs)->msr)
#define get_mc_reason(regs)     ((regs)->msr)
#define REASON_FP               0x100000
#define REASON_ILLEGAL          0x80000
#define REASON_PRIVILEGED       0x40000
#define REASON_TRAP             0x20000

#define single_stepping(regs)   ((regs)->msr & MSR_SE)
#define clear_single_step(regs) ((regs)->msr &= ~MSR_SE)
#endif

/*
 * This is "fall-back" implementation for configurations
 * which don't provide platform-specific machine check info
 */
void __attribute__ ((weak))
platform_machine_check(struct pt_regs *regs)
{
}

void machine_check_exception(struct pt_regs *regs)
{
        unsigned long reason = get_mc_reason(regs);

        if (user_mode(regs)) {
                regs->msr |= MSR_RI;
                _exception(SIGBUS, regs, BUS_ADRERR, regs->nip);
                return;
        }

#if defined(CONFIG_8xx) && defined(CONFIG_PCI)
        /* the qspan pci read routines can cause machine checks -- Cort */
        bad_page_fault(regs, regs->dar, SIGBUS);
        return;
#endif

        if (debugger_fault_handler) {
                debugger_fault_handler(regs);
                regs->msr |= MSR_RI;
                return;
        }

        if (check_io_access(regs))
                return;

#if defined(CONFIG_4xx) && !defined(CONFIG_440A)
        if (reason & ESR_IMCP) {
                printk("Instruction");
                mtspr(SPRN_ESR, reason & ~ESR_IMCP);
        } else
                printk("Data");
        printk(" machine check in kernel mode.\n");
#elif defined(CONFIG_440A)
        printk("Machine check in kernel mode.\n");
        if (reason & ESR_IMCP){
                printk("Instruction Synchronous Machine Check exception\n");
                mtspr(SPRN_ESR, reason & ~ESR_IMCP);
        }
        else {
                u32 mcsr = mfspr(SPRN_MCSR);
                if (mcsr & MCSR_IB)
                        printk("Instruction Read PLB Error\n");
                if (mcsr & MCSR_DRB)
                        printk("Data Read PLB Error\n");
                if (mcsr & MCSR_DWB)
                        printk("Data Write PLB Error\n");
                if (mcsr & MCSR_TLBP)
                        printk("TLB Parity Error\n");
                if (mcsr & MCSR_ICP){
                        flush_instruction_cache();
                        printk("I-Cache Parity Error\n");
                }
                if (mcsr & MCSR_DCSP)
                        printk("D-Cache Search Parity Error\n");
                if (mcsr & MCSR_DCFP)
                        printk("D-Cache Flush Parity Error\n");
                if (mcsr & MCSR_IMPE)
                        printk("Machine Check exception is imprecise\n");

                /* Clear MCSR */
                mtspr(SPRN_MCSR, mcsr);
        }
#elif defined (CONFIG_E500)
        printk("Machine check in kernel mode.\n");
        printk("Caused by (from MCSR=%lx): ", reason);

        if (reason & MCSR_MCP)
                printk("Machine Check Signal\n");
        if (reason & MCSR_ICPERR)
                printk("Instruction Cache Parity Error\n");
        if (reason & MCSR_DCP_PERR)
                printk("Data Cache Push Parity Error\n");
        if (reason & MCSR_DCPERR)
                printk("Data Cache Parity Error\n");
        if (reason & MCSR_GL_CI)
                printk("Guarded Load or Cache-Inhibited stwcx.\n");
        if (reason & MCSR_BUS_IAERR)
                printk("Bus - Instruction Address Error\n");
        if (reason & MCSR_BUS_RAERR)
                printk("Bus - Read Address Error\n");
        if (reason & MCSR_BUS_WAERR)
                printk("Bus - Write Address Error\n");
        if (reason & MCSR_BUS_IBERR)
                printk("Bus - Instruction Data Error\n");
        if (reason & MCSR_BUS_RBERR)
                printk("Bus - Read Data Bus Error\n");
        if (reason & MCSR_BUS_WBERR)
                printk("Bus - Read Data Bus Error\n");
        if (reason & MCSR_BUS_IPERR)
                printk("Bus - Instruction Parity Error\n");
        if (reason & MCSR_BUS_RPERR)
                printk("Bus - Read Parity Error\n");
#elif defined (CONFIG_E200)
        printk("Machine check in kernel mode.\n");
        printk("Caused by (from MCSR=%lx): ", reason);

        if (reason & MCSR_MCP)
                printk("Machine Check Signal\n");
        if (reason & MCSR_CP_PERR)
                printk("Cache Push Parity Error\n");
        if (reason & MCSR_CPERR)
                printk("Cache Parity Error\n");
        if (reason & MCSR_EXCP_ERR)
                printk("ISI, ITLB, or Bus Error on first instruction fetch for an exception handler\n");
        if (reason & MCSR_BUS_IRERR)
                printk("Bus - Read Bus Error on instruction fetch\n");
        if (reason & MCSR_BUS_DRERR)
                printk("Bus - Read Bus Error on data load\n");
        if (reason & MCSR_BUS_WRERR)
                printk("Bus - Write Bus Error on buffered store or cache line push\n");
#else /* !CONFIG_4xx && !CONFIG_E500 && !CONFIG_E200 */
        printk("Machine check in kernel mode.\n");
        printk("Caused by (from SRR1=%lx): ", reason);
        switch (reason & 0x601F0000) {
        case 0x80000:
                printk("Machine check signal\n");
                break;
        case 0:         /* for 601 */
        case 0x40000:
        case 0x140000:  /* 7450 MSS error and TEA */
                printk("Transfer error ack signal\n");
                break;
        case 0x20000:
                printk("Data parity error signal\n");
                break;
        case 0x10000:
                printk("Address parity error signal\n");
                break;
        case 0x20000000:
                printk("L1 Data Cache error\n");
                break;
        case 0x40000000:
                printk("L1 Instruction Cache error\n");
                break;
        case 0x00100000:
                printk("L2 data cache parity error\n");
                break;
        default:
                printk("Unknown values in msr\n");
        }
#endif /* CONFIG_4xx */

        /*
         * Optional platform-provided routine to print out
         * additional info, e.g. bus error registers.
         */
        platform_machine_check(regs);

        debugger(regs);
        die("machine check", regs, SIGBUS);
}

void SMIException(struct pt_regs *regs)
{
        debugger(regs);
#if !(defined(CONFIG_XMON) || defined(CONFIG_KGDB))
        show_regs(regs);
        panic("System Management Interrupt");
#endif
}

void unknown_exception(struct pt_regs *regs)
{
        printk("Bad trap at PC: %lx, MSR: %lx, vector=%lx    %s\n",
               regs->nip, regs->msr, regs->trap, print_tainted());
        _exception(SIGTRAP, regs, 0, 0);
}

void instruction_breakpoint_exception(struct pt_regs *regs)
{
        if (debugger_iabr_match(regs))
                return;
        _exception(SIGTRAP, regs, TRAP_BRKPT, 0);
}

void RunModeException(struct pt_regs *regs)
{
        _exception(SIGTRAP, regs, 0, 0);
}

/* Illegal instruction emulation support.  Originally written to
 * provide the PVR to user applications using the mfspr rd, PVR.
 * Return non-zero if we can't emulate, or -EFAULT if the associated
 * memory access caused an access fault.  Return zero on success.
 *
 * There are a couple of ways to do this, either "decode" the instruction
 * or directly match lots of bits.  In this case, matching lots of
 * bits is faster and easier.
 *
 */
#define INST_MFSPR_PVR          0x7c1f42a6
#define INST_MFSPR_PVR_MASK     0xfc1fffff

#define INST_DCBA               0x7c0005ec
#define INST_DCBA_MASK          0x7c0007fe

#define INST_MCRXR              0x7c000400
#define INST_MCRXR_MASK         0x7c0007fe

#define INST_STRING             0x7c00042a
#define INST_STRING_MASK        0x7c0007fe
#define INST_STRING_GEN_MASK    0x7c00067e
#define INST_LSWI               0x7c0004aa
#define INST_LSWX               0x7c00042a
#define INST_STSWI              0x7c0005aa
#define INST_STSWX              0x7c00052a

static int emulate_string_inst(struct pt_regs *regs, u32 instword)
{
        u8 rT = (instword >> 21) & 0x1f;
        u8 rA = (instword >> 16) & 0x1f;
        u8 NB_RB = (instword >> 11) & 0x1f;
        u32 num_bytes;
        unsigned long EA;
        int pos = 0;

        /* Early out if we are an invalid form of lswx */
        if ((instword & INST_STRING_MASK) == INST_LSWX)
                if ((rT == rA) || (rT == NB_RB))
                        return -EINVAL;

        EA = (rA == 0) ? 0 : regs->gpr[rA];

        switch (instword & INST_STRING_MASK) {
                case INST_LSWX:
                case INST_STSWX:
                        EA += NB_RB;
                        num_bytes = regs->xer & 0x7f;
                        break;
                case INST_LSWI:
                case INST_STSWI:
                        num_bytes = (NB_RB == 0) ? 32 : NB_RB;
                        break;
                default:
                        return -EINVAL;
        }

        while (num_bytes != 0)
        {
                u8 val;
                u32 shift = 8 * (3 - (pos & 0x3));

                switch ((instword & INST_STRING_MASK)) {
                        case INST_LSWX:
                        case INST_LSWI:
                                if (get_user(val, (u8 __user *)EA))
                                        return -EFAULT;
                                /* first time updating this reg,
                                 * zero it out */
                                if (pos == 0)
                                        regs->gpr[rT] = 0;
                                regs->gpr[rT] |= val << shift;
                                break;
                        case INST_STSWI:
                        case INST_STSWX:
                                val = regs->gpr[rT] >> shift;
                                if (put_user(val, (u8 __user *)EA))
                                        return -EFAULT;
                                break;
                }
                /* move EA to next address */
                EA += 1;
                num_bytes--;

                /* manage our position within the register */
                if (++pos == 4) {
                        pos = 0;
                        if (++rT == 32)
                                rT = 0;
                }
        }

        return 0;
}

static int emulate_instruction(struct pt_regs *regs)
{
        u32 instword;
        u32 rd;

        if (!user_mode(regs))
                return -EINVAL;
        CHECK_FULL_REGS(regs);

        if (get_user(instword, (u32 __user *)(regs->nip)))
                return -EFAULT;

        /* Emulate the mfspr rD, PVR.
         */
        if ((instword & INST_MFSPR_PVR_MASK) == INST_MFSPR_PVR) {
                rd = (instword >> 21) & 0x1f;
                regs->gpr[rd] = mfspr(SPRN_PVR);
                return 0;
        }

        /* Emulating the dcba insn is just a no-op.  */
        if ((instword & INST_DCBA_MASK) == INST_DCBA)
                return 0;

        /* Emulate the mcrxr insn.  */
        if ((instword & INST_MCRXR_MASK) == INST_MCRXR) {
                int shift = (instword >> 21) & 0x1c;
                unsigned long msk = 0xf0000000UL >> shift;

                regs->ccr = (regs->ccr & ~msk) | ((regs->xer >> shift) & msk);
                regs->xer &= ~0xf0000000UL;
                return 0;
        }

        /* Emulate load/store string insn. */
        if ((instword & INST_STRING_GEN_MASK) == INST_STRING)
                return emulate_string_inst(regs, instword);

        return -EINVAL;
}

/*
 * After we have successfully emulated an instruction, we have to
 * check if the instruction was being single-stepped, and if so,
 * pretend we got a single-step exception.  This was pointed out
 * by Kumar Gala.  -- paulus
 */
static void emulate_single_step(struct pt_regs *regs)
{
        if (single_stepping(regs)) {
                clear_single_step(regs);
                _exception(SIGTRAP, regs, TRAP_TRACE, 0);
        }
}

/*
 * Look through the list of trap instructions that are used for BUG(),
 * BUG_ON() and WARN_ON() and see if we hit one.  At this point we know
 * that the exception was caused by a trap instruction of some kind.
 * Returns 1 if we should continue (i.e. it was a WARN_ON) or 0
 * otherwise.
 */
extern struct bug_entry __start___bug_table[], __stop___bug_table[];

#ifndef CONFIG_MODULES
#define module_find_bug(x)      NULL
#endif

struct bug_entry *find_bug(unsigned long bugaddr)
{
        struct bug_entry *bug;

        for (bug = __start___bug_table; bug < __stop___bug_table; ++bug)
                if (bugaddr == bug->bug_addr)
                        return bug;
        return module_find_bug(bugaddr);
}

int check_bug_trap(struct pt_regs *regs)
{
        struct bug_entry *bug;
        unsigned long addr;

        if (regs->msr & MSR_PR)
                return 0;       /* not in kernel */
        addr = regs->nip;       /* address of trap instruction */
        if (addr < PAGE_OFFSET)
                return 0;
        bug = find_bug(regs->nip);
        if (bug == NULL)
                return 0;
        if (bug->line & BUG_WARNING_TRAP) {
                /* this is a WARN_ON rather than BUG/BUG_ON */
#ifdef CONFIG_XMON
                xmon_printf(KERN_ERR "Badness in %s at %s:%ld\n",
                       bug->function, bug->file,
                       bug->line & ~BUG_WARNING_TRAP);
#endif /* CONFIG_XMON */                
                printk(KERN_ERR "Badness in %s at %s:%ld\n",
                       bug->function, bug->file,
                       bug->line & ~BUG_WARNING_TRAP);
                dump_stack();
                return 1;
        }
#ifdef CONFIG_XMON
        xmon_printf(KERN_CRIT "kernel BUG in %s at %s:%ld!\n",
               bug->function, bug->file, bug->line);
        xmon(regs);
#endif /* CONFIG_XMON */
        printk(KERN_CRIT "kernel BUG in %s at %s:%ld!\n",
               bug->function, bug->file, bug->line);

        return 0;
}

void program_check_exception(struct pt_regs *regs)
{
        unsigned int reason = get_reason(regs);
        extern int do_mathemu(struct pt_regs *regs);

#ifdef CONFIG_MATH_EMULATION
        /* (reason & REASON_ILLEGAL) would be the obvious thing here,
         * but there seems to be a hardware bug on the 405GP (RevD)
         * that means ESR is sometimes set incorrectly - either to
         * ESR_DST (!?) or 0.  In the process of chasing this with the
         * hardware people - not sure if it can happen on any illegal
         * instruction or only on FP instructions, whether there is a
         * pattern to occurences etc. -dgibson 31/Mar/2003 */
        if (!(reason & REASON_TRAP) && do_mathemu(regs) == 0) {
                emulate_single_step(regs);
                return;
        }
#endif /* CONFIG_MATH_EMULATION */

        if (reason & REASON_FP) {
                /* IEEE FP exception */
                int code = 0;
                u32 fpscr;

                /* We must make sure the FP state is consistent with
                 * our MSR_FP in regs
                 */
                preempt_disable();
                if (regs->msr & MSR_FP)
                        giveup_fpu(current);
                preempt_enable();

                fpscr = current->thread.fpscr.val;
                fpscr &= fpscr << 22;   /* mask summary bits with enables */
                if (fpscr & FPSCR_VX)
                        code = FPE_FLTINV;
                else if (fpscr & FPSCR_OX)
                        code = FPE_FLTOVF;
                else if (fpscr & FPSCR_UX)
                        code = FPE_FLTUND;
                else if (fpscr & FPSCR_ZX)
                        code = FPE_FLTDIV;
                else if (fpscr & FPSCR_XX)
                        code = FPE_FLTRES;
                _exception(SIGFPE, regs, code, regs->nip);
                return;
        }

        if (reason & REASON_TRAP) {
                /* trap exception */
                if (debugger_bpt(regs))
                        return;
                if (check_bug_trap(regs)) {
                        regs->nip += 4;
                        return;
                }
                _exception(SIGTRAP, regs, TRAP_BRKPT, 0);
                return;
        }

        /* Try to emulate it if we should. */
        if (reason & (REASON_ILLEGAL | REASON_PRIVILEGED)) {
                switch (emulate_instruction(regs)) {
                case 0:
                        regs->nip += 4;
                        emulate_single_step(regs);
                        return;
                case -EFAULT:
                        _exception(SIGSEGV, regs, SEGV_MAPERR, regs->nip);
                        return;
                }
        }

        if (reason & REASON_PRIVILEGED)
                _exception(SIGILL, regs, ILL_PRVOPC, regs->nip);
        else
                _exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
}

void single_step_exception(struct pt_regs *regs)
{
        regs->msr &= ~(MSR_SE | MSR_BE);  /* Turn off 'trace' bits */
        if (debugger_sstep(regs))
                return;
        _exception(SIGTRAP, regs, TRAP_TRACE, 0);
}

void alignment_exception(struct pt_regs *regs)
{
        int fixed;

        fixed = fix_alignment(regs);
        if (fixed == 1) {
                regs->nip += 4; /* skip over emulated instruction */
                emulate_single_step(regs);
                return;
        }
        if (fixed == -EFAULT) {
                /* fixed == -EFAULT means the operand address was bad */
                if (user_mode(regs))
                        _exception(SIGSEGV, regs, SEGV_ACCERR, regs->dar);
                else
                        bad_page_fault(regs, regs->dar, SIGSEGV);
                return;
        }
        _exception(SIGBUS, regs, BUS_ADRALN, regs->dar);
}

void StackOverflow(struct pt_regs *regs)
{
        printk(KERN_CRIT "Kernel stack overflow in process %p, r1=%lx\n",
               current, regs->gpr[1]);
        debugger(regs);
        show_regs(regs);
        panic("kernel stack overflow");
}

void nonrecoverable_exception(struct pt_regs *regs)
{
        printk(KERN_ERR "Non-recoverable exception at PC=%lx MSR=%lx\n",
               regs->nip, regs->msr);
        debugger(regs);
        die("nonrecoverable exception", regs, SIGKILL);
}

void trace_syscall(struct pt_regs *regs)
{
        printk("Task: %p(%d), PC: %08lX/%08lX, Syscall: %3ld, Result: %s%ld    %s\n",
               current, current->pid, regs->nip, regs->link, regs->gpr[0],
               regs->ccr&0x10000000?"Error=":"", regs->gpr[3], print_tainted());
}

#ifdef CONFIG_8xx
void SoftwareEmulation(struct pt_regs *regs)
{
        extern int do_mathemu(struct pt_regs *);
        extern int Soft_emulate_8xx(struct pt_regs *);
        int errcode;

        CHECK_FULL_REGS(regs);

        if (!user_mode(regs)) {
                debugger(regs);
                die("Kernel Mode Software FPU Emulation", regs, SIGFPE);
        }

#ifdef CONFIG_MATH_EMULATION
        errcode = do_mathemu(regs);
#else
        errcode = Soft_emulate_8xx(regs);
#endif
        if (errcode) {
                if (errcode > 0)
                        _exception(SIGFPE, regs, 0, 0);
                else if (errcode == -EFAULT)
                        _exception(SIGSEGV, regs, 0, 0);
                else
                        _exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
        } else
                emulate_single_step(regs);
}
#endif /* CONFIG_8xx */

#if defined(CONFIG_40x) || defined(CONFIG_BOOKE)

void DebugException(struct pt_regs *regs, unsigned long debug_status)
{
        if (debug_status & DBSR_IC) {   /* instruction completion */
                regs->msr &= ~MSR_DE;
                if (user_mode(regs)) {
                        current->thread.dbcr0 &= ~DBCR0_IC;
                } else {
                        /* Disable instruction completion */
                        mtspr(SPRN_DBCR0, mfspr(SPRN_DBCR0) & ~DBCR0_IC);
                        /* Clear the instruction completion event */
                        mtspr(SPRN_DBSR, DBSR_IC);
                        if (debugger_sstep(regs))
                                return;
                }
                _exception(SIGTRAP, regs, TRAP_TRACE, 0);
        }
}
#endif /* CONFIG_4xx || CONFIG_BOOKE */

#if !defined(CONFIG_TAU_INT)
void TAUException(struct pt_regs *regs)
{
        printk("TAU trap at PC: %lx, MSR: %lx, vector=%lx    %s\n",
               regs->nip, regs->msr, regs->trap, print_tainted());
}
#endif /* CONFIG_INT_TAU */

/*
 * FP unavailable trap from kernel - print a message, but let
 * the task use FP in the kernel until it returns to user mode.
 */
void kernel_fp_unavailable_exception(struct pt_regs *regs)
{
        regs->msr |= MSR_FP;
        printk(KERN_ERR "floating point used in kernel (task=%p, pc=%lx)\n",
               current, regs->nip);
}

void altivec_unavailable_exception(struct pt_regs *regs)
{
        static int kernel_altivec_count;

#ifndef CONFIG_ALTIVEC
        if (user_mode(regs)) {
                /* A user program has executed an altivec instruction,
                   but this kernel doesn't support altivec. */
                _exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
                return;
        }
#endif
        /* The kernel has executed an altivec instruction without
           first enabling altivec.  Whinge but let it do it. */
        if (++kernel_altivec_count < 10)
                printk(KERN_ERR "AltiVec used in kernel (task=%p, pc=%lx)\n",
                       current, regs->nip);
        regs->msr |= MSR_VEC;
}

#ifdef CONFIG_ALTIVEC
void altivec_assist_exception(struct pt_regs *regs)
{
        int err;

        preempt_disable();
        if (regs->msr & MSR_VEC)
                giveup_altivec(current);
        preempt_enable();
        if (!user_mode(regs)) {
                printk(KERN_ERR "altivec assist exception in kernel mode"
                       " at %lx\n", regs->nip);
                debugger(regs);
                die("altivec assist exception", regs, SIGFPE);
                return;
        }

        err = emulate_altivec(regs);
        if (err == 0) {
                regs->nip += 4;         /* skip emulated instruction */
                emulate_single_step(regs);
                return;
        }

        if (err == -EFAULT) {
                /* got an error reading the instruction */
                _exception(SIGSEGV, regs, SEGV_ACCERR, regs->nip);
        } else {
                /* didn't recognize the instruction */
                /* XXX quick hack for now: set the non-Java bit in the VSCR */
                printk(KERN_ERR "unrecognized altivec instruction "
                       "in %s at %lx\n", current->comm, regs->nip);
                current->thread.vscr.u[3] |= 0x10000;
        }
}
#endif /* CONFIG_ALTIVEC */

#ifdef CONFIG_E500
void performance_monitor_exception(struct pt_regs *regs)
{
        perf_irq(regs);
}
#endif

#ifdef CONFIG_FSL_BOOKE
void CacheLockingException(struct pt_regs *regs, unsigned long address,
                           unsigned long error_code)
{
        /* We treat cache locking instructions from the user
         * as priv ops, in the future we could try to do
         * something smarter
         */
        if (error_code & (ESR_DLK|ESR_ILK))
                _exception(SIGILL, regs, ILL_PRVOPC, regs->nip);
        return;
}
#endif /* CONFIG_FSL_BOOKE */

#ifdef CONFIG_SPE
void SPEFloatingPointException(struct pt_regs *regs)
{
        unsigned long spefscr;
        int fpexc_mode;
        int code = 0;

        spefscr = current->thread.spefscr;
        fpexc_mode = current->thread.fpexc_mode;

        /* Hardware does not neccessarily set sticky
         * underflow/overflow/invalid flags */
        if ((spefscr & SPEFSCR_FOVF) && (fpexc_mode & PR_FP_EXC_OVF)) {
                code = FPE_FLTOVF;
                spefscr |= SPEFSCR_FOVFS;
        }
        else if ((spefscr & SPEFSCR_FUNF) && (fpexc_mode & PR_FP_EXC_UND)) {
                code = FPE_FLTUND;
                spefscr |= SPEFSCR_FUNFS;
        }
        else if ((spefscr & SPEFSCR_FDBZ) && (fpexc_mode & PR_FP_EXC_DIV))
                code = FPE_FLTDIV;
        else if ((spefscr & SPEFSCR_FINV) && (fpexc_mode & PR_FP_EXC_INV)) {
                code = FPE_FLTINV;
                spefscr |= SPEFSCR_FINVS;
        }
        else if ((spefscr & (SPEFSCR_FG | SPEFSCR_FX)) && (fpexc_mode & PR_FP_EXC_RES))
                code = FPE_FLTRES;

        current->thread.spefscr = spefscr;

        _exception(SIGFPE, regs, code, regs->nip);
        return;
}
#endif

#ifdef CONFIG_BOOKE_WDT
/*
 * Default handler for a Watchdog exception,
 * spins until a reboot occurs
 */
void __attribute__ ((weak)) WatchdogHandler(struct pt_regs *regs)
{
        /* Generic WatchdogHandler, implement your own */
        mtspr(SPRN_TCR, mfspr(SPRN_TCR)&(~TCR_WIE));
        return;
}

void WatchdogException(struct pt_regs *regs)
{
        printk (KERN_EMERG "PowerPC Book-E Watchdog Exception\n");
        WatchdogHandler(regs);
}
#endif

void __init trap_init(void)
{
}