powerpc: Fix emulation of illegal instructions on PowerNV platform

[GitHub/LineageOS/android_kernel_motorola_exynos9610.git] / arch / powerpc / kernel / traps.c

/*
 *  Copyright (C) 1995-1996  Gary Thomas (gdt@linuxppc.org)
 *  Copyright 2007-2010 Freescale Semiconductor, Inc.
 *
 *  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@samba.org)
 */

/*
 * 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/user.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/prctl.h>
#include <linux/delay.h>
#include <linux/kprobes.h>
#include <linux/kexec.h>
#include <linux/backlight.h>
#include <linux/bug.h>
#include <linux/kdebug.h>
#include <linux/debugfs.h>
#include <linux/ratelimit.h>
#include <linux/context_tracking.h>

#include <asm/emulated_ops.h>
#include <asm/pgtable.h>
#include <asm/uaccess.h>
#include <asm/io.h>
#include <asm/machdep.h>
#include <asm/rtas.h>
#include <asm/pmc.h>
#ifdef CONFIG_PPC32
#include <asm/reg.h>
#endif
#ifdef CONFIG_PMAC_BACKLIGHT
#include <asm/backlight.h>
#endif
#ifdef CONFIG_PPC64
#include <asm/firmware.h>
#include <asm/processor.h>
#include <asm/tm.h>
#endif
#include <asm/kexec.h>
#include <asm/ppc-opcode.h>
#include <asm/rio.h>
#include <asm/fadump.h>
#include <asm/switch_to.h>
#include <asm/tm.h>
#include <asm/debug.h>

#if defined(CONFIG_DEBUGGER) || defined(CONFIG_KEXEC)
int (*__debugger)(struct pt_regs *regs) __read_mostly;
int (*__debugger_ipi)(struct pt_regs *regs) __read_mostly;
int (*__debugger_bpt)(struct pt_regs *regs) __read_mostly;
int (*__debugger_sstep)(struct pt_regs *regs) __read_mostly;
int (*__debugger_iabr_match)(struct pt_regs *regs) __read_mostly;
int (*__debugger_break_match)(struct pt_regs *regs) __read_mostly;
int (*__debugger_fault_handler)(struct pt_regs *regs) __read_mostly;

EXPORT_SYMBOL(__debugger);
EXPORT_SYMBOL(__debugger_ipi);
EXPORT_SYMBOL(__debugger_bpt);
EXPORT_SYMBOL(__debugger_sstep);
EXPORT_SYMBOL(__debugger_iabr_match);
EXPORT_SYMBOL(__debugger_break_match);
EXPORT_SYMBOL(__debugger_fault_handler);
#endif

/* Transactional Memory trap debug */
#ifdef TM_DEBUG_SW
#define TM_DEBUG(x...) printk(KERN_INFO x)
#else
#define TM_DEBUG(x...) do { } while(0)
#endif

/*
 * Trap & Exception support
 */

#ifdef CONFIG_PMAC_BACKLIGHT
static void pmac_backlight_unblank(void)
{
        mutex_lock(&pmac_backlight_mutex);
        if (pmac_backlight) {
                struct backlight_properties *props;

                props = &pmac_backlight->props;
                props->brightness = props->max_brightness;
                props->power = FB_BLANK_UNBLANK;
                backlight_update_status(pmac_backlight);
        }
        mutex_unlock(&pmac_backlight_mutex);
}
#else
static inline void pmac_backlight_unblank(void) { }
#endif

static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
static int die_owner = -1;
static unsigned int die_nest_count;
static int die_counter;

static unsigned __kprobes long oops_begin(struct pt_regs *regs)
{
        int cpu;
        unsigned long flags;

        if (debugger(regs))
                return 1;

        oops_enter();

        /* racy, but better than risking deadlock. */
        raw_local_irq_save(flags);
        cpu = smp_processor_id();
        if (!arch_spin_trylock(&die_lock)) {
                if (cpu == die_owner)
                        /* nested oops. should stop eventually */;
                else
                        arch_spin_lock(&die_lock);
        }
        die_nest_count++;
        die_owner = cpu;
        console_verbose();
        bust_spinlocks(1);
        if (machine_is(powermac))
                pmac_backlight_unblank();
        return flags;
}

static void __kprobes oops_end(unsigned long flags, struct pt_regs *regs,
                               int signr)
{
        bust_spinlocks(0);
        die_owner = -1;
        add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
        die_nest_count--;
        oops_exit();
        printk("\n");
        if (!die_nest_count)
                /* Nest count reaches zero, release the lock. */
                arch_spin_unlock(&die_lock);
        raw_local_irq_restore(flags);

        crash_fadump(regs, "die oops");

        /*
         * A system reset (0x100) is a request to dump, so we always send
         * it through the crashdump code.
         */
        if (kexec_should_crash(current) || (TRAP(regs) == 0x100)) {
                crash_kexec(regs);

                /*
                 * We aren't the primary crash CPU. We need to send it
                 * to a holding pattern to avoid it ending up in the panic
                 * code.
                 */
                crash_kexec_secondary(regs);
        }

        if (!signr)
                return;

        /*
         * While our oops output is serialised by a spinlock, output
         * from panic() called below can race and corrupt it. If we
         * know we are going to panic, delay for 1 second so we have a
         * chance to get clean backtraces from all CPUs that are oopsing.
         */
        if (in_interrupt() || panic_on_oops || !current->pid ||
            is_global_init(current)) {
                mdelay(MSEC_PER_SEC);
        }

        if (in_interrupt())
                panic("Fatal exception in interrupt");
        if (panic_on_oops)
                panic("Fatal exception");
        do_exit(signr);
}

static int __kprobes __die(const char *str, struct pt_regs *regs, long err)
{
        printk("Oops: %s, sig: %ld [#%d]\n", str, err, ++die_counter);
#ifdef CONFIG_PREEMPT
        printk("PREEMPT ");
#endif
#ifdef CONFIG_SMP
        printk("SMP NR_CPUS=%d ", NR_CPUS);
#endif
#ifdef CONFIG_DEBUG_PAGEALLOC
        printk("DEBUG_PAGEALLOC ");
#endif
#ifdef CONFIG_NUMA
        printk("NUMA ");
#endif
        printk("%s\n", ppc_md.name ? ppc_md.name : "");

        if (notify_die(DIE_OOPS, str, regs, err, 255, SIGSEGV) == NOTIFY_STOP)
                return 1;

        print_modules();
        show_regs(regs);

        return 0;
}

void die(const char *str, struct pt_regs *regs, long err)
{
        unsigned long flags = oops_begin(regs);

        if (__die(str, regs, err))
                err = 0;
        oops_end(flags, regs, err);
}

void user_single_step_siginfo(struct task_struct *tsk,
                                struct pt_regs *regs, siginfo_t *info)
{
        memset(info, 0, sizeof(*info));
        info->si_signo = SIGTRAP;
        info->si_code = TRAP_TRACE;
        info->si_addr = (void __user *)regs->nip;
}

void _exception(int signr, struct pt_regs *regs, int code, unsigned long addr)
{
        siginfo_t info;
        const char fmt32[] = KERN_INFO "%s[%d]: unhandled signal %d " \
                        "at %08lx nip %08lx lr %08lx code %x\n";
        const char fmt64[] = KERN_INFO "%s[%d]: unhandled signal %d " \
                        "at %016lx nip %016lx lr %016lx code %x\n";

        if (!user_mode(regs)) {
                die("Exception in kernel mode", regs, signr);
                return;
        }

        if (show_unhandled_signals && unhandled_signal(current, signr)) {
                printk_ratelimited(regs->msr & MSR_64BIT ? fmt64 : fmt32,
                                   current->comm, current->pid, signr,
                                   addr, regs->nip, regs->link, code);
        }

        if (arch_irqs_disabled() && !arch_irq_disabled_regs(regs))
                local_irq_enable();

        current->thread.trap_nr = code;
        memset(&info, 0, sizeof(info));
        info.si_signo = signr;
        info.si_code = code;
        info.si_addr = (void __user *) addr;
        force_sig_info(signr, &info, current);
}

#ifdef CONFIG_PPC64
void system_reset_exception(struct pt_regs *regs)
{
        /* See if any machine dependent calls */
        if (ppc_md.system_reset_exception) {
                if (ppc_md.system_reset_exception(regs))
                        return;
        }

        die("System Reset", regs, SIGABRT);

        /* Must die if the interrupt is not recoverable */
        if (!(regs->msr & MSR_RI))
                panic("Unrecoverable System Reset");

        /* What should we do here? We could issue a shutdown or hard reset. */
}
#endif

/*
 * 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)
{
#ifdef CONFIG_PPC32
        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;
                if (*nip == 0x7c0004ac || (*nip >> 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_PPC32 */
        return 0;
}

#ifdef CONFIG_PPC_ADV_DEBUG_REGS
/* 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_TM               0x200000
#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

#if defined(CONFIG_4xx)
int machine_check_4xx(struct pt_regs *regs)
{
        unsigned long reason = get_mc_reason(regs);

        if (reason & ESR_IMCP) {
                printk("Instruction");
                mtspr(SPRN_ESR, reason & ~ESR_IMCP);
        } else
                printk("Data");
        printk(" machine check in kernel mode.\n");

        return 0;
}

int machine_check_440A(struct pt_regs *regs)
{
        unsigned long reason = get_mc_reason(regs);

        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);
        }
        return 0;
}

int machine_check_47x(struct pt_regs *regs)
{
        unsigned long reason = get_mc_reason(regs);
        u32 mcsr;

        printk(KERN_ERR "Machine check in kernel mode.\n");
        if (reason & ESR_IMCP) {
                printk(KERN_ERR
                       "Instruction Synchronous Machine Check exception\n");
                mtspr(SPRN_ESR, reason & ~ESR_IMCP);
                return 0;
        }
        mcsr = mfspr(SPRN_MCSR);
        if (mcsr & MCSR_IB)
                printk(KERN_ERR "Instruction Read PLB Error\n");
        if (mcsr & MCSR_DRB)
                printk(KERN_ERR "Data Read PLB Error\n");
        if (mcsr & MCSR_DWB)
                printk(KERN_ERR "Data Write PLB Error\n");
        if (mcsr & MCSR_TLBP)
                printk(KERN_ERR "TLB Parity Error\n");
        if (mcsr & MCSR_ICP) {
                flush_instruction_cache();
                printk(KERN_ERR "I-Cache Parity Error\n");
        }
        if (mcsr & MCSR_DCSP)
                printk(KERN_ERR "D-Cache Search Parity Error\n");
        if (mcsr & PPC47x_MCSR_GPR)
                printk(KERN_ERR "GPR Parity Error\n");
        if (mcsr & PPC47x_MCSR_FPR)
                printk(KERN_ERR "FPR Parity Error\n");
        if (mcsr & PPC47x_MCSR_IPR)
                printk(KERN_ERR "Machine Check exception is imprecise\n");

        /* Clear MCSR */
        mtspr(SPRN_MCSR, mcsr);

        return 0;
}
#elif defined(CONFIG_E500)
int machine_check_e500mc(struct pt_regs *regs)
{
        unsigned long mcsr = mfspr(SPRN_MCSR);
        unsigned long reason = mcsr;
        int recoverable = 1;

        if (reason & MCSR_LD) {
                recoverable = fsl_rio_mcheck_exception(regs);
                if (recoverable == 1)
                        goto silent_out;
        }

        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");

                /*
                 * This is recoverable by invalidating the i-cache.
                 */
                mtspr(SPRN_L1CSR1, mfspr(SPRN_L1CSR1) | L1CSR1_ICFI);
                while (mfspr(SPRN_L1CSR1) & L1CSR1_ICFI)
                        ;

                /*
                 * This will generally be accompanied by an instruction
                 * fetch error report -- only treat MCSR_IF as fatal
                 * if it wasn't due to an L1 parity error.
                 */
                reason &= ~MCSR_IF;
        }

        if (reason & MCSR_DCPERR_MC) {
                printk("Data Cache Parity Error\n");

                /*
                 * In write shadow mode we auto-recover from the error, but it
                 * may still get logged and cause a machine check.  We should
                 * only treat the non-write shadow case as non-recoverable.
                 */
                if (!(mfspr(SPRN_L1CSR2) & L1CSR2_DCWS))
                        recoverable = 0;
        }

        if (reason & MCSR_L2MMU_MHIT) {
                printk("Hit on multiple TLB entries\n");
                recoverable = 0;
        }

        if (reason & MCSR_NMI)
                printk("Non-maskable interrupt\n");

        if (reason & MCSR_IF) {
                printk("Instruction Fetch Error Report\n");
                recoverable = 0;
        }

        if (reason & MCSR_LD) {
                printk("Load Error Report\n");
                recoverable = 0;
        }

        if (reason & MCSR_ST) {
                printk("Store Error Report\n");
                recoverable = 0;
        }

        if (reason & MCSR_LDG) {
                printk("Guarded Load Error Report\n");
                recoverable = 0;
        }

        if (reason & MCSR_TLBSYNC)
                printk("Simultaneous tlbsync operations\n");

        if (reason & MCSR_BSL2_ERR) {
                printk("Level 2 Cache Error\n");
                recoverable = 0;
        }

        if (reason & MCSR_MAV) {
                u64 addr;

                addr = mfspr(SPRN_MCAR);
                addr |= (u64)mfspr(SPRN_MCARU) << 32;

                printk("Machine Check %s Address: %#llx\n",
                       reason & MCSR_MEA ? "Effective" : "Physical", addr);
        }

silent_out:
        mtspr(SPRN_MCSR, mcsr);
        return mfspr(SPRN_MCSR) == 0 && recoverable;
}

int machine_check_e500(struct pt_regs *regs)
{
        unsigned long reason = get_mc_reason(regs);

        if (reason & MCSR_BUS_RBERR) {
                if (fsl_rio_mcheck_exception(regs))
                        return 1;
        }

        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_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");

        return 0;
}

int machine_check_generic(struct pt_regs *regs)
{
        return 0;
}
#elif defined(CONFIG_E200)
int machine_check_e200(struct pt_regs *regs)
{
        unsigned long reason = get_mc_reason(regs);

        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");

        return 0;
}
#else
int machine_check_generic(struct pt_regs *regs)
{
        unsigned long reason = get_mc_reason(regs);

        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");
        }
        return 0;
}
#endif /* everything else */

void machine_check_exception(struct pt_regs *regs)
{
        enum ctx_state prev_state = exception_enter();
        int recover = 0;

        __get_cpu_var(irq_stat).mce_exceptions++;

        /* See if any machine dependent calls. In theory, we would want
         * to call the CPU first, and call the ppc_md. one if the CPU
         * one returns a positive number. However there is existing code
         * that assumes the board gets a first chance, so let's keep it
         * that way for now and fix things later. --BenH.
         */
        if (ppc_md.machine_check_exception)
                recover = ppc_md.machine_check_exception(regs);
        else if (cur_cpu_spec->machine_check)
                recover = cur_cpu_spec->machine_check(regs);

        if (recover > 0)
                goto bail;

#if defined(CONFIG_8xx) && defined(CONFIG_PCI)
        /* the qspan pci read routines can cause machine checks -- Cort
         *
         * yuck !!! that totally needs to go away ! There are better ways
         * to deal with that than having a wart in the mcheck handler.
         * -- BenH
         */
        bad_page_fault(regs, regs->dar, SIGBUS);
        goto bail;
#endif

        if (debugger_fault_handler(regs))
                goto bail;

        if (check_io_access(regs))
                goto bail;

        die("Machine check", regs, SIGBUS);

        /* Must die if the interrupt is not recoverable */
        if (!(regs->msr & MSR_RI))
                panic("Unrecoverable Machine check");

bail:
        exception_exit(prev_state);
}

void SMIException(struct pt_regs *regs)
{
        die("System Management Interrupt", regs, SIGABRT);
}

void unknown_exception(struct pt_regs *regs)
{
        enum ctx_state prev_state = exception_enter();

        printk("Bad trap at PC: %lx, SR: %lx, vector=%lx\n",
               regs->nip, regs->msr, regs->trap);

        _exception(SIGTRAP, regs, 0, 0);

        exception_exit(prev_state);
}

void instruction_breakpoint_exception(struct pt_regs *regs)
{
        enum ctx_state prev_state = exception_enter();

        if (notify_die(DIE_IABR_MATCH, "iabr_match", regs, 5,
                                        5, SIGTRAP) == NOTIFY_STOP)
                goto bail;
        if (debugger_iabr_match(regs))
                goto bail;
        _exception(SIGTRAP, regs, TRAP_BRKPT, regs->nip);

bail:
        exception_exit(prev_state);
}

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

void __kprobes single_step_exception(struct pt_regs *regs)
{
        enum ctx_state prev_state = exception_enter();

        clear_single_step(regs);

        if (notify_die(DIE_SSTEP, "single_step", regs, 5,
                                        5, SIGTRAP) == NOTIFY_STOP)
                goto bail;
        if (debugger_sstep(regs))
                goto bail;

        _exception(SIGTRAP, regs, TRAP_TRACE, regs->nip);

bail:
        exception_exit(prev_state);
}

/*
 * 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))
                single_step_exception(regs);
}

static inline int __parse_fpscr(unsigned long fpscr)
{
        int ret = 0;

        /* Invalid operation */
        if ((fpscr & FPSCR_VE) && (fpscr & FPSCR_VX))
                ret = FPE_FLTINV;

        /* Overflow */
        else if ((fpscr & FPSCR_OE) && (fpscr & FPSCR_OX))
                ret = FPE_FLTOVF;

        /* Underflow */
        else if ((fpscr & FPSCR_UE) && (fpscr & FPSCR_UX))
                ret = FPE_FLTUND;

        /* Divide by zero */
        else if ((fpscr & FPSCR_ZE) && (fpscr & FPSCR_ZX))
                ret = FPE_FLTDIV;

        /* Inexact result */
        else if ((fpscr & FPSCR_XE) && (fpscr & FPSCR_XX))
                ret = FPE_FLTRES;

        return ret;
}

static void parse_fpe(struct pt_regs *regs)
{
        int code = 0;

        flush_fp_to_thread(current);

        code = __parse_fpscr(current->thread.fpscr.val);

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

/*
 * 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.
 *
 */
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 & PPC_INST_STRING_MASK) == PPC_INST_LSWX)
                if ((rT == rA) || (rT == NB_RB))
                        return -EINVAL;

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

        switch (instword & PPC_INST_STRING_MASK) {
                case PPC_INST_LSWX:
                case PPC_INST_STSWX:
                        EA += NB_RB;
                        num_bytes = regs->xer & 0x7f;
                        break;
                case PPC_INST_LSWI:
                case PPC_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 & PPC_INST_STRING_MASK)) {
                        case PPC_INST_LSWX:
                        case PPC_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 PPC_INST_STSWI:
                        case PPC_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_popcntb_inst(struct pt_regs *regs, u32 instword)
{
        u32 ra,rs;
        unsigned long tmp;

        ra = (instword >> 16) & 0x1f;
        rs = (instword >> 21) & 0x1f;

        tmp = regs->gpr[rs];
        tmp = tmp - ((tmp >> 1) & 0x5555555555555555ULL);
        tmp = (tmp & 0x3333333333333333ULL) + ((tmp >> 2) & 0x3333333333333333ULL);
        tmp = (tmp + (tmp >> 4)) & 0x0f0f0f0f0f0f0f0fULL;
        regs->gpr[ra] = tmp;

        return 0;
}

static int emulate_isel(struct pt_regs *regs, u32 instword)
{
        u8 rT = (instword >> 21) & 0x1f;
        u8 rA = (instword >> 16) & 0x1f;
        u8 rB = (instword >> 11) & 0x1f;
        u8 BC = (instword >> 6) & 0x1f;
        u8 bit;
        unsigned long tmp;

        tmp = (rA == 0) ? 0 : regs->gpr[rA];
        bit = (regs->ccr >> (31 - BC)) & 0x1;

        regs->gpr[rT] = bit ? tmp : regs->gpr[rB];

        return 0;
}

#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
static inline bool tm_abort_check(struct pt_regs *regs, int cause)
{
        /* If we're emulating a load/store in an active transaction, we cannot
         * emulate it as the kernel operates in transaction suspended context.
         * We need to abort the transaction.  This creates a persistent TM
         * abort so tell the user what caused it with a new code.
         */
        if (MSR_TM_TRANSACTIONAL(regs->msr)) {
                tm_enable();
                tm_abort(cause);
                return true;
        }
        return false;
}
#else
static inline bool tm_abort_check(struct pt_regs *regs, int reason)
{
        return false;
}
#endif

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

        if (!user_mode(regs) || (regs->msr & MSR_LE))
                return -EINVAL;
        CHECK_FULL_REGS(regs);

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

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

        /* Emulating the dcba insn is just a no-op.  */
        if ((instword & PPC_INST_DCBA_MASK) == PPC_INST_DCBA) {
                PPC_WARN_EMULATED(dcba, regs);
                return 0;
        }

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

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

        /* Emulate load/store string insn. */
        if ((instword & PPC_INST_STRING_GEN_MASK) == PPC_INST_STRING) {
                if (tm_abort_check(regs,
                                   TM_CAUSE_EMULATE | TM_CAUSE_PERSISTENT))
                        return -EINVAL;
                PPC_WARN_EMULATED(string, regs);
                return emulate_string_inst(regs, instword);
        }

        /* Emulate the popcntb (Population Count Bytes) instruction. */
        if ((instword & PPC_INST_POPCNTB_MASK) == PPC_INST_POPCNTB) {
                PPC_WARN_EMULATED(popcntb, regs);
                return emulate_popcntb_inst(regs, instword);
        }

        /* Emulate isel (Integer Select) instruction */
        if ((instword & PPC_INST_ISEL_MASK) == PPC_INST_ISEL) {
                PPC_WARN_EMULATED(isel, regs);
                return emulate_isel(regs, instword);
        }

#ifdef CONFIG_PPC64
        /* Emulate the mfspr rD, DSCR. */
        if ((((instword & PPC_INST_MFSPR_DSCR_USER_MASK) ==
                PPC_INST_MFSPR_DSCR_USER) ||
             ((instword & PPC_INST_MFSPR_DSCR_MASK) ==
                PPC_INST_MFSPR_DSCR)) &&
                        cpu_has_feature(CPU_FTR_DSCR)) {
                PPC_WARN_EMULATED(mfdscr, regs);
                rd = (instword >> 21) & 0x1f;
                regs->gpr[rd] = mfspr(SPRN_DSCR);
                return 0;
        }
        /* Emulate the mtspr DSCR, rD. */
        if ((((instword & PPC_INST_MTSPR_DSCR_USER_MASK) ==
                PPC_INST_MTSPR_DSCR_USER) ||
             ((instword & PPC_INST_MTSPR_DSCR_MASK) ==
                PPC_INST_MTSPR_DSCR)) &&
                        cpu_has_feature(CPU_FTR_DSCR)) {
                PPC_WARN_EMULATED(mtdscr, regs);
                rd = (instword >> 21) & 0x1f;
                current->thread.dscr = regs->gpr[rd];
                current->thread.dscr_inherit = 1;
                mtspr(SPRN_DSCR, current->thread.dscr);
                return 0;
        }
#endif

        return -EINVAL;
}

int is_valid_bugaddr(unsigned long addr)
{
        return is_kernel_addr(addr);
}

void __kprobes program_check_exception(struct pt_regs *regs)
{
        enum ctx_state prev_state = exception_enter();
        unsigned int reason = get_reason(regs);
        extern int do_mathemu(struct pt_regs *regs);

        /* We can now get here via a FP Unavailable exception if the core
         * has no FPU, in that case the reason flags will be 0 */

        if (reason & REASON_FP) {
                /* IEEE FP exception */
                parse_fpe(regs);
                goto bail;
        }
        if (reason & REASON_TRAP) {
                /* Debugger is first in line to stop recursive faults in
                 * rcu_lock, notify_die, or atomic_notifier_call_chain */
                if (debugger_bpt(regs))
                        goto bail;

                /* trap exception */
                if (notify_die(DIE_BPT, "breakpoint", regs, 5, 5, SIGTRAP)
                                == NOTIFY_STOP)
                        goto bail;

                if (!(regs->msr & MSR_PR) &&  /* not user-mode */
                    report_bug(regs->nip, regs) == BUG_TRAP_TYPE_WARN) {
                        regs->nip += 4;
                        goto bail;
                }
                _exception(SIGTRAP, regs, TRAP_BRKPT, regs->nip);
                goto bail;
        }
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
        if (reason & REASON_TM) {
                /* This is a TM "Bad Thing Exception" program check.
                 * This occurs when:
                 * -  An rfid/hrfid/mtmsrd attempts to cause an illegal
                 *    transition in TM states.
                 * -  A trechkpt is attempted when transactional.
                 * -  A treclaim is attempted when non transactional.
                 * -  A tend is illegally attempted.
                 * -  writing a TM SPR when transactional.
                 */
                if (!user_mode(regs) &&
                    report_bug(regs->nip, regs) == BUG_TRAP_TYPE_WARN) {
                        regs->nip += 4;
                        goto bail;
                }
                /* If usermode caused this, it's done something illegal and
                 * gets a SIGILL slap on the wrist.  We call it an illegal
                 * operand to distinguish from the instruction just being bad
                 * (e.g. executing a 'tend' on a CPU without TM!); it's an
                 * illegal /placement/ of a valid instruction.
                 */
                if (user_mode(regs)) {
                        _exception(SIGILL, regs, ILL_ILLOPN, regs->nip);
                        goto bail;
                } else {
                        printk(KERN_EMERG "Unexpected TM Bad Thing exception "
                               "at %lx (msr 0x%x)\n", regs->nip, reason);
                        die("Unrecoverable exception", regs, SIGABRT);
                }
        }
#endif

        /* We restore the interrupt state now */
        if (!arch_irq_disabled_regs(regs))
                local_irq_enable();

#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 occurrences etc. -dgibson 31/Mar/2003 */
        switch (do_mathemu(regs)) {
        case 0:
                emulate_single_step(regs);
                goto bail;
        case 1: {
                        int code = 0;
                        code = __parse_fpscr(current->thread.fpscr.val);
                        _exception(SIGFPE, regs, code, regs->nip);
                        goto bail;
                }
        case -EFAULT:
                _exception(SIGSEGV, regs, SEGV_MAPERR, regs->nip);
                goto bail;
        }
        /* fall through on any other errors */
#endif /* CONFIG_MATH_EMULATION */

        /* 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);
                        goto bail;
                case -EFAULT:
                        _exception(SIGSEGV, regs, SEGV_MAPERR, regs->nip);
                        goto bail;
                }
        }

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

bail:
        exception_exit(prev_state);
}

/*
 * This occurs when running in hypervisor mode on POWER6 or later
 * and an illegal instruction is encountered.
 */
void __kprobes emulation_assist_interrupt(struct pt_regs *regs)
{
        regs->msr |= REASON_ILLEGAL;
        program_check_exception(regs);
}

void alignment_exception(struct pt_regs *regs)
{
        enum ctx_state prev_state = exception_enter();
        int sig, code, fixed = 0;

        /* We restore the interrupt state now */
        if (!arch_irq_disabled_regs(regs))
                local_irq_enable();

        if (tm_abort_check(regs, TM_CAUSE_ALIGNMENT | TM_CAUSE_PERSISTENT))
                goto bail;

        /* we don't implement logging of alignment exceptions */
        if (!(current->thread.align_ctl & PR_UNALIGN_SIGBUS))
                fixed = fix_alignment(regs);

        if (fixed == 1) {
                regs->nip += 4; /* skip over emulated instruction */
                emulate_single_step(regs);
                goto bail;
        }

        /* Operand address was bad */
        if (fixed == -EFAULT) {
                sig = SIGSEGV;
                code = SEGV_ACCERR;
        } else {
                sig = SIGBUS;
                code = BUS_ADRALN;
        }
        if (user_mode(regs))
                _exception(sig, regs, code, regs->dar);
        else
                bad_page_fault(regs, regs->dar, sig);

bail:
        exception_exit(prev_state);
}

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, task_pid_nr(current), regs->nip, regs->link, regs->gpr[0],
               regs->ccr&0x10000000?"Error=":"", regs->gpr[3], print_tainted());
}

void kernel_fp_unavailable_exception(struct pt_regs *regs)
{
        enum ctx_state prev_state = exception_enter();

        printk(KERN_EMERG "Unrecoverable FP Unavailable Exception "
                          "%lx at %lx\n", regs->trap, regs->nip);
        die("Unrecoverable FP Unavailable Exception", regs, SIGABRT);

        exception_exit(prev_state);
}

void altivec_unavailable_exception(struct pt_regs *regs)
{
        enum ctx_state prev_state = exception_enter();

        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);
                goto bail;
        }

        printk(KERN_EMERG "Unrecoverable VMX/Altivec Unavailable Exception "
                        "%lx at %lx\n", regs->trap, regs->nip);
        die("Unrecoverable VMX/Altivec Unavailable Exception", regs, SIGABRT);

bail:
        exception_exit(prev_state);
}

void vsx_unavailable_exception(struct pt_regs *regs)
{
        if (user_mode(regs)) {
                /* A user program has executed an vsx instruction,
                   but this kernel doesn't support vsx. */
                _exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
                return;
        }

        printk(KERN_EMERG "Unrecoverable VSX Unavailable Exception "
                        "%lx at %lx\n", regs->trap, regs->nip);
        die("Unrecoverable VSX Unavailable Exception", regs, SIGABRT);
}

void tm_unavailable_exception(struct pt_regs *regs)
{
        /* We restore the interrupt state now */
        if (!arch_irq_disabled_regs(regs))
                local_irq_enable();

        /* Currently we never expect a TMU exception.  Catch
         * this and kill the process!
         */
        printk(KERN_EMERG "Unexpected TM unavailable exception at %lx "
               "(msr %lx)\n",
               regs->nip, regs->msr);

        if (user_mode(regs)) {
                _exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
                return;
        }

        die("Unexpected TM unavailable exception", regs, SIGABRT);
}

#ifdef CONFIG_PPC_TRANSACTIONAL_MEM

extern void do_load_up_fpu(struct pt_regs *regs);

void fp_unavailable_tm(struct pt_regs *regs)
{
        /* Note:  This does not handle any kind of FP laziness. */

        TM_DEBUG("FP Unavailable trap whilst transactional at 0x%lx, MSR=%lx\n",
                 regs->nip, regs->msr);
        tm_enable();

        /* We can only have got here if the task started using FP after
         * beginning the transaction.  So, the transactional regs are just a
         * copy of the checkpointed ones.  But, we still need to recheckpoint
         * as we're enabling FP for the process; it will return, abort the
         * transaction, and probably retry but now with FP enabled.  So the
         * checkpointed FP registers need to be loaded.
         */
        tm_reclaim(&current->thread, current->thread.regs->msr,
                   TM_CAUSE_FAC_UNAV);
        /* Reclaim didn't save out any FPRs to transact_fprs. */

        /* Enable FP for the task: */
        regs->msr |= (MSR_FP | current->thread.fpexc_mode);

        /* This loads and recheckpoints the FP registers from
         * thread.fpr[].  They will remain in registers after the
         * checkpoint so we don't need to reload them after.
         */
        tm_recheckpoint(&current->thread, regs->msr);
}

#ifdef CONFIG_ALTIVEC
extern void do_load_up_altivec(struct pt_regs *regs);

void altivec_unavailable_tm(struct pt_regs *regs)
{
        /* See the comments in fp_unavailable_tm().  This function operates
         * the same way.
         */

        TM_DEBUG("Vector Unavailable trap whilst transactional at 0x%lx,"
                 "MSR=%lx\n",
                 regs->nip, regs->msr);
        tm_enable();
        tm_reclaim(&current->thread, current->thread.regs->msr,
                   TM_CAUSE_FAC_UNAV);
        regs->msr |= MSR_VEC;
        tm_recheckpoint(&current->thread, regs->msr);
        current->thread.used_vr = 1;
}
#endif

#ifdef CONFIG_VSX
void vsx_unavailable_tm(struct pt_regs *regs)
{
        /* See the comments in fp_unavailable_tm().  This works similarly,
         * though we're loading both FP and VEC registers in here.
         *
         * If FP isn't in use, load FP regs.  If VEC isn't in use, load VEC
         * regs.  Either way, set MSR_VSX.
         */

        TM_DEBUG("VSX Unavailable trap whilst transactional at 0x%lx,"
                 "MSR=%lx\n",
                 regs->nip, regs->msr);

        tm_enable();
        /* This reclaims FP and/or VR regs if they're already enabled */
        tm_reclaim(&current->thread, current->thread.regs->msr,
                   TM_CAUSE_FAC_UNAV);

        regs->msr |= MSR_VEC | MSR_FP | current->thread.fpexc_mode |
                MSR_VSX;
        /* This loads & recheckpoints FP and VRs. */
        tm_recheckpoint(&current->thread, regs->msr);
        current->thread.used_vsr = 1;
}
#endif
#endif /* CONFIG_PPC_TRANSACTIONAL_MEM */

void performance_monitor_exception(struct pt_regs *regs)
{
        __get_cpu_var(irq_stat).pmu_irqs++;

        perf_irq(regs);
}

#ifdef CONFIG_8xx
void SoftwareEmulation(struct pt_regs *regs)
{
        extern int do_mathemu(struct pt_regs *);
        extern int Soft_emulate_8xx(struct pt_regs *);
#if defined(CONFIG_MATH_EMULATION) || defined(CONFIG_8XX_MINIMAL_FPEMU)
        int errcode;
#endif

        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);
        if (errcode >= 0)
                PPC_WARN_EMULATED(math, regs);

        switch (errcode) {
        case 0:
                emulate_single_step(regs);
                return;
        case 1: {
                        int code = 0;
                        code = __parse_fpscr(current->thread.fpscr.val);
                        _exception(SIGFPE, regs, code, regs->nip);
                        return;
                }
        case -EFAULT:
                _exception(SIGSEGV, regs, SEGV_MAPERR, regs->nip);
                return;
        default:
                _exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
                return;
        }

#elif defined(CONFIG_8XX_MINIMAL_FPEMU)
        errcode = Soft_emulate_8xx(regs);
        if (errcode >= 0)
                PPC_WARN_EMULATED(8xx, regs);

        switch (errcode) {
        case 0:
                emulate_single_step(regs);
                return;
        case 1:
                _exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
                return;
        case -EFAULT:
                _exception(SIGSEGV, regs, SEGV_MAPERR, regs->nip);
                return;
        }
#else
        _exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
#endif
}
#endif /* CONFIG_8xx */

#ifdef CONFIG_PPC_ADV_DEBUG_REGS
static void handle_debug(struct pt_regs *regs, unsigned long debug_status)
{
        int changed = 0;
        /*
         * Determine the cause of the debug event, clear the
         * event flags and send a trap to the handler. Torez
         */
        if (debug_status & (DBSR_DAC1R | DBSR_DAC1W)) {
                dbcr_dac(current) &= ~(DBCR_DAC1R | DBCR_DAC1W);
#ifdef CONFIG_PPC_ADV_DEBUG_DAC_RANGE
                current->thread.dbcr2 &= ~DBCR2_DAC12MODE;
#endif
                do_send_trap(regs, mfspr(SPRN_DAC1), debug_status, TRAP_HWBKPT,
                             5);
                changed |= 0x01;
        }  else if (debug_status & (DBSR_DAC2R | DBSR_DAC2W)) {
                dbcr_dac(current) &= ~(DBCR_DAC2R | DBCR_DAC2W);
                do_send_trap(regs, mfspr(SPRN_DAC2), debug_status, TRAP_HWBKPT,
                             6);
                changed |= 0x01;
        }  else if (debug_status & DBSR_IAC1) {
                current->thread.dbcr0 &= ~DBCR0_IAC1;
                dbcr_iac_range(current) &= ~DBCR_IAC12MODE;
                do_send_trap(regs, mfspr(SPRN_IAC1), debug_status, TRAP_HWBKPT,
                             1);
                changed |= 0x01;
        }  else if (debug_status & DBSR_IAC2) {
                current->thread.dbcr0 &= ~DBCR0_IAC2;
                do_send_trap(regs, mfspr(SPRN_IAC2), debug_status, TRAP_HWBKPT,
                             2);
                changed |= 0x01;
        }  else if (debug_status & DBSR_IAC3) {
                current->thread.dbcr0 &= ~DBCR0_IAC3;
                dbcr_iac_range(current) &= ~DBCR_IAC34MODE;
                do_send_trap(regs, mfspr(SPRN_IAC3), debug_status, TRAP_HWBKPT,
                             3);
                changed |= 0x01;
        }  else if (debug_status & DBSR_IAC4) {
                current->thread.dbcr0 &= ~DBCR0_IAC4;
                do_send_trap(regs, mfspr(SPRN_IAC4), debug_status, TRAP_HWBKPT,
                             4);
                changed |= 0x01;
        }
        /*
         * At the point this routine was called, the MSR(DE) was turned off.
         * Check all other debug flags and see if that bit needs to be turned
         * back on or not.
         */
        if (DBCR_ACTIVE_EVENTS(current->thread.dbcr0, current->thread.dbcr1))
                regs->msr |= MSR_DE;
        else
                /* Make sure the IDM flag is off */
                current->thread.dbcr0 &= ~DBCR0_IDM;

        if (changed & 0x01)
                mtspr(SPRN_DBCR0, current->thread.dbcr0);
}

void __kprobes DebugException(struct pt_regs *regs, unsigned long debug_status)
{
        current->thread.dbsr = debug_status;

        /* Hack alert: On BookE, Branch Taken stops on the branch itself, while
         * on server, it stops on the target of the branch. In order to simulate
         * the server behaviour, we thus restart right away with a single step
         * instead of stopping here when hitting a BT
         */
        if (debug_status & DBSR_BT) {
                regs->msr &= ~MSR_DE;

                /* Disable BT */
                mtspr(SPRN_DBCR0, mfspr(SPRN_DBCR0) & ~DBCR0_BT);
                /* Clear the BT event */
                mtspr(SPRN_DBSR, DBSR_BT);

                /* Do the single step trick only when coming from userspace */
                if (user_mode(regs)) {
                        current->thread.dbcr0 &= ~DBCR0_BT;
                        current->thread.dbcr0 |= DBCR0_IDM | DBCR0_IC;
                        regs->msr |= MSR_DE;
                        return;
                }

                if (notify_die(DIE_SSTEP, "block_step", regs, 5,
                               5, SIGTRAP) == NOTIFY_STOP) {
                        return;
                }
                if (debugger_sstep(regs))
                        return;
        } else if (debug_status & DBSR_IC) {    /* Instruction complete */
                regs->msr &= ~MSR_DE;

                /* Disable instruction completion */
                mtspr(SPRN_DBCR0, mfspr(SPRN_DBCR0) & ~DBCR0_IC);
                /* Clear the instruction completion event */
                mtspr(SPRN_DBSR, DBSR_IC);

                if (notify_die(DIE_SSTEP, "single_step", regs, 5,
                               5, SIGTRAP) == NOTIFY_STOP) {
                        return;
                }

                if (debugger_sstep(regs))
                        return;

                if (user_mode(regs)) {
                        current->thread.dbcr0 &= ~DBCR0_IC;
                        if (DBCR_ACTIVE_EVENTS(current->thread.dbcr0,
                                               current->thread.dbcr1))
                                regs->msr |= MSR_DE;
                        else
                                /* Make sure the IDM bit is off */
                                current->thread.dbcr0 &= ~DBCR0_IDM;
                }

                _exception(SIGTRAP, regs, TRAP_TRACE, regs->nip);
        } else
                handle_debug(regs, debug_status);
}
#endif /* CONFIG_PPC_ADV_DEBUG_REGS */

#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 */

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

        if (!user_mode(regs)) {
                printk(KERN_EMERG "VMX/Altivec assist exception in kernel mode"
                       " at %lx\n", regs->nip);
                die("Kernel VMX/Altivec assist exception", regs, SIGILL);
        }

        flush_altivec_to_thread(current);

        PPC_WARN_EMULATED(altivec, regs);
        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_ratelimited(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_VSX
void vsx_assist_exception(struct pt_regs *regs)
{
        if (!user_mode(regs)) {
                printk(KERN_EMERG "VSX assist exception in kernel mode"
                       " at %lx\n", regs->nip);
                die("Kernel VSX assist exception", regs, SIGILL);
        }

        flush_vsx_to_thread(current);
        printk(KERN_INFO "VSX assist not supported at %lx\n", regs->nip);
        _exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
}
#endif /* CONFIG_VSX */

#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)
{
        extern int do_spe_mathemu(struct pt_regs *regs);
        unsigned long spefscr;
        int fpexc_mode;
        int code = 0;
        int err;

        flush_spe_to_thread(current);

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

        if ((spefscr & SPEFSCR_FOVF) && (fpexc_mode & PR_FP_EXC_OVF)) {
                code = FPE_FLTOVF;
        }
        else if ((spefscr & SPEFSCR_FUNF) && (fpexc_mode & PR_FP_EXC_UND)) {
                code = FPE_FLTUND;
        }
        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;
        }
        else if ((spefscr & (SPEFSCR_FG | SPEFSCR_FX)) && (fpexc_mode & PR_FP_EXC_RES))
                code = FPE_FLTRES;

        err = do_spe_mathemu(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 if (err == -EINVAL) {
                /* didn't recognize the instruction */
                printk(KERN_ERR "unrecognized spe instruction "
                       "in %s at %lx\n", current->comm, regs->nip);
        } else {
                _exception(SIGFPE, regs, code, regs->nip);
        }

        return;
}

void SPEFloatingPointRoundException(struct pt_regs *regs)
{
        extern int speround_handler(struct pt_regs *regs);
        int err;

        preempt_disable();
        if (regs->msr & MSR_SPE)
                giveup_spe(current);
        preempt_enable();

        regs->nip -= 4;
        err = speround_handler(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 if (err == -EINVAL) {
                /* didn't recognize the instruction */
                printk(KERN_ERR "unrecognized spe instruction "
                       "in %s at %lx\n", current->comm, regs->nip);
        } else {
                _exception(SIGFPE, regs, 0, regs->nip);
                return;
        }
}
#endif

/*
 * We enter here if we get an unrecoverable exception, that is, one
 * that happened at a point where the RI (recoverable interrupt) bit
 * in the MSR is 0.  This indicates that SRR0/1 are live, and that
 * we therefore lost state by taking this exception.
 */
void unrecoverable_exception(struct pt_regs *regs)
{
        printk(KERN_EMERG "Unrecoverable exception %lx at %lx\n",
               regs->trap, regs->nip);
        die("Unrecoverable exception", regs, SIGABRT);
}

#if defined(CONFIG_BOOKE_WDT) || defined(CONFIG_40x)
/*
 * 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

/*
 * We enter here if we discover during exception entry that we are
 * running in supervisor mode with a userspace value in the stack pointer.
 */
void kernel_bad_stack(struct pt_regs *regs)
{
        printk(KERN_EMERG "Bad kernel stack pointer %lx at %lx\n",
               regs->gpr[1], regs->nip);
        die("Bad kernel stack pointer", regs, SIGABRT);
}

void __init trap_init(void)
{
}


#ifdef CONFIG_PPC_EMULATED_STATS

#define WARN_EMULATED_SETUP(type)       .type = { .name = #type }

struct ppc_emulated ppc_emulated = {
#ifdef CONFIG_ALTIVEC
        WARN_EMULATED_SETUP(altivec),
#endif
        WARN_EMULATED_SETUP(dcba),
        WARN_EMULATED_SETUP(dcbz),
        WARN_EMULATED_SETUP(fp_pair),
        WARN_EMULATED_SETUP(isel),
        WARN_EMULATED_SETUP(mcrxr),
        WARN_EMULATED_SETUP(mfpvr),
        WARN_EMULATED_SETUP(multiple),
        WARN_EMULATED_SETUP(popcntb),
        WARN_EMULATED_SETUP(spe),
        WARN_EMULATED_SETUP(string),
        WARN_EMULATED_SETUP(unaligned),
#ifdef CONFIG_MATH_EMULATION
        WARN_EMULATED_SETUP(math),
#elif defined(CONFIG_8XX_MINIMAL_FPEMU)
        WARN_EMULATED_SETUP(8xx),
#endif
#ifdef CONFIG_VSX
        WARN_EMULATED_SETUP(vsx),
#endif
#ifdef CONFIG_PPC64
        WARN_EMULATED_SETUP(mfdscr),
        WARN_EMULATED_SETUP(mtdscr),
#endif
};

u32 ppc_warn_emulated;

void ppc_warn_emulated_print(const char *type)
{
        pr_warn_ratelimited("%s used emulated %s instruction\n", current->comm,
                            type);
}

static int __init ppc_warn_emulated_init(void)
{
        struct dentry *dir, *d;
        unsigned int i;
        struct ppc_emulated_entry *entries = (void *)&ppc_emulated;

        if (!powerpc_debugfs_root)
                return -ENODEV;

        dir = debugfs_create_dir("emulated_instructions",
                                 powerpc_debugfs_root);
        if (!dir)
                return -ENOMEM;

        d = debugfs_create_u32("do_warn", S_IRUGO | S_IWUSR, dir,
                               &ppc_warn_emulated);
        if (!d)
                goto fail;

        for (i = 0; i < sizeof(ppc_emulated)/sizeof(*entries); i++) {
                d = debugfs_create_u32(entries[i].name, S_IRUGO | S_IWUSR, dir,
                                       (u32 *)&entries[i].val.counter);
                if (!d)
                        goto fail;
        }

        return 0;

fail:
        debugfs_remove_recursive(dir);
        return -ENOMEM;
}

device_initcall(ppc_warn_emulated_init);

#endif /* CONFIG_PPC_EMULATED_STATS */