/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * arch/sh64/kernel/traps.c
 *
 * Copyright (C) 2000, 2001  Paolo Alberelli
 * Copyright (C) 2003  Paul Mundt
 * Copyright (C) 2003  Richard Curnow
 *
 */

/*
 * 'Traps.c' handles hardware traps and faults after we have saved some
 * state in 'entry.S'.
 */
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/timer.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/spinlock.h>

#include <linux/interrupt.h>
#include <linux/sysctl.h>

#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/io.h>
#include <asm/atomic.h>
#include <asm/processor.h>
#include <asm/pgtable.h>

#undef DEBUG_EXCEPTION
#ifdef DEBUG_EXCEPTION
/* implemented in ../lib/dbg.c */
extern void show_excp_regs(char *fname, int trapnr, int signr,
                           struct pt_regs *regs);
#else
#define show_excp_regs(a, b, c, d)
#endif

static void do_unhandled_exception(int trapnr, int signr, char *str, char *fn_name,
                unsigned long error_code, struct pt_regs *regs, struct task_struct *tsk);

#define DO_ERROR(trapnr, signr, str, name, tsk) \
asmlinkage void do_##name(unsigned long error_code, struct pt_regs *regs) \
{ \
        do_unhandled_exception(trapnr, signr, str, __FUNCTION__, error_code, regs, current); \
}

spinlock_t die_lock;

void die(const char * str, struct pt_regs * regs, long err)
{
        console_verbose();
        spin_lock_irq(&die_lock);
        printk("%s: %lx\n", str, (err & 0xffffff));
        show_regs(regs);
        spin_unlock_irq(&die_lock);
        do_exit(SIGSEGV);
}

static inline void die_if_kernel(const char * str, struct pt_regs * regs, long err)
{
        if (!user_mode(regs))
                die(str, regs, err);
}

static void die_if_no_fixup(const char * str, struct pt_regs * regs, long err)
{
        if (!user_mode(regs))
        {
                unsigned long fixup;
                fixup = search_exception_table(regs->pc);
                if (fixup) {
                        regs->pc = fixup;
                        return;
                }
                die(str, regs, err);
        }
}

DO_ERROR(13, SIGILL,  "illegal slot instruction", illegal_slot_inst, current)
DO_ERROR(87, SIGSEGV, "address error (exec)", address_error_exec, current)


/* Implement misaligned load/store handling for kernel (and optionally for user
   mode too).  Limitation : only SHmedia mode code is handled - there is no
   handling at all for misaligned accesses occurring in SHcompact code yet. */

static int misaligned_fixup(struct pt_regs *regs);

asmlinkage void do_address_error_load(unsigned long error_code, struct pt_regs *regs)
{
        if (misaligned_fixup(regs) < 0) {
                do_unhandled_exception(7, SIGSEGV, "address error(load)", __FUNCTION__,
                                error_code, regs, current);
        }
        return;
}

asmlinkage void do_address_error_store(unsigned long error_code, struct pt_regs *regs)
{
        if (misaligned_fixup(regs) < 0) {
                do_unhandled_exception(8, SIGSEGV, "address error(store)", __FUNCTION__,
                                error_code, regs, current);
        }
        return;
}

#if defined(CONFIG_SH64_ID2815_WORKAROUND)

#define OPCODE_INVALID      0
#define OPCODE_USER_VALID   1
#define OPCODE_PRIV_VALID   2

/* getcon/putcon - requires checking which control register is referenced. */
#define OPCODE_CTRL_REG     3

/* Table of valid opcodes for SHmedia mode.
   Form a 10-bit value by concatenating the major/minor opcodes i.e.
   opcode[31:26,20:16].  The 6 MSBs of this value index into the following
   array.  The 4 LSBs select the bit-pair in the entry (bits 1:0 correspond to
   LSBs==4'b0000 etc). */
static unsigned long shmedia_opcode_table[64] = {
        0x55554044,0x54445055,0x15141514,0x14541414,0x00000000,0x10001000,0x01110055,0x04050015,
        0x00000444,0xc0000000,0x44545515,0x40405555,0x55550015,0x10005555,0x55555505,0x04050000,
        0x00000555,0x00000404,0x00040445,0x15151414,0x00000000,0x00000000,0x00000000,0x00000000,
        0x00000055,0x40404444,0x00000404,0xc0009495,0x00000000,0x00000000,0x00000000,0x00000000,
        0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,
        0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,
        0x80005050,0x04005055,0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,
        0x81055554,0x00000404,0x55555555,0x55555555,0x00000000,0x00000000,0x00000000,0x00000000
};

void do_reserved_inst(unsigned long error_code, struct pt_regs *regs)
{
        /* Workaround SH5-101 cut2 silicon defect #2815 :
           in some situations, inter-mode branches from SHcompact -> SHmedia
           which should take ITLBMISS or EXECPROT exceptions at the target
           falsely take RESINST at the target instead. */

        unsigned long opcode = 0x6ff4fff0; /* guaranteed reserved opcode */
        unsigned long pc, aligned_pc;
        int get_user_error;
        int trapnr = 12;
        int signr = SIGILL;
        char *exception_name = "reserved_instruction";

        pc = regs->pc;
        if ((pc & 3) == 1) {
                /* SHmedia : check for defect.  This requires executable vmas
                   to be readable too. */
                aligned_pc = pc & ~3;
                if (!access_ok(VERIFY_READ, aligned_pc, sizeof(unsigned long))) {
                        get_user_error = -EFAULT;
                } else {
                        get_user_error = __get_user(opcode, (unsigned long *)aligned_pc);
                }
                if (get_user_error >= 0) {
                        unsigned long index, shift;
                        unsigned long major, minor, combined;
                        unsigned long reserved_field;
                        reserved_field = opcode & 0xf; /* These bits are currently reserved as zero in all valid opcodes */
                        major = (opcode >> 26) & 0x3f;
                        minor = (opcode >> 16) & 0xf;
                        combined = (major << 4) | minor;
                        index = major;
                        shift = minor << 1;
                        if (reserved_field == 0) {
                                int opcode_state = (shmedia_opcode_table[index] >> shift) & 0x3;
                                switch (opcode_state) {
                                        case OPCODE_INVALID:
                                                /* Trap. */
                                                break;
                                        case OPCODE_USER_VALID:
                                                /* Restart the instruction : the branch to the instruction will now be from an RTE
                                                   not from SHcompact so the silicon defect won't be triggered. */
                                                return;
                                        case OPCODE_PRIV_VALID:
                                                if (!user_mode(regs)) {
                                                        /* Should only ever get here if a module has
                                                           SHcompact code inside it.  If so, the same fix up is needed. */
                                                        return; /* same reason */
                                                }
                                                /* Otherwise, user mode trying to execute a privileged instruction - 
                                                   fall through to trap. */
                                                break;
                                        case OPCODE_CTRL_REG:
                                                /* If in privileged mode, return as above. */
                                                if (!user_mode(regs)) return; 
                                                /* In user mode ... */
                                                if (combined == 0x9f) { /* GETCON */
                                                        unsigned long regno = (opcode >> 20) & 0x3f;
                                                        if (regno >= 62) {
                                                                return;
                                                        }
                                                        /* Otherwise, reserved or privileged control register, => trap */
                                                } else if (combined == 0x1bf) { /* PUTCON */
                                                        unsigned long regno = (opcode >> 4) & 0x3f;
                                                        if (regno >= 62) {
                                                                return;
                                                        }
                                                        /* Otherwise, reserved or privileged control register, => trap */
                                                } else {
                                                        /* Trap */
                                                }
                                                break;
                                        default:
                                                /* Fall through to trap. */
                                                break;
                                }
                        }
                        /* fall through to normal resinst processing */
                } else {
                        /* Error trying to read opcode.  This typically means a
                           real fault, not a RESINST any more.  So change the
                           codes. */
                        trapnr = 87;
                        exception_name = "address error (exec)";
                        signr = SIGSEGV;
                }
        }

        do_unhandled_exception(trapnr, signr, exception_name, "do_reserved_inst", error_code, regs, current);
}

#else /* CONFIG_SH64_ID2815_WORKAROUND */

/* If the workaround isn't needed, this is just a straightforward reserved
   instruction */
DO_ERROR(12, SIGILL,  "reserved instruction", reserved_inst, current)

#endif /* CONFIG_SH64_ID2815_WORKAROUND */


#include <asm/system.h>

/* Called with interrupts disabled */
asmlinkage void do_exception_error(unsigned long ex, struct pt_regs *regs)
{
        PLS();
        show_excp_regs(__FUNCTION__, -1, -1, regs);
        die_if_kernel("exception", regs, ex);
}

int do_unknown_trapa(unsigned long scId, struct pt_regs *regs)
{       
        /* Syscall debug */
        printk("System call ID error: [0x1#args:8 #syscall:16  0x%lx]\n", scId);

        die_if_kernel("unknown trapa", regs, scId);

        return -ENOSYS;
}

void show_task(unsigned long *sp)
{
        unsigned long module_start, module_end;
        unsigned long kernel_start, kernel_end;
        unsigned long *stack;
        extern int _text, _etext;
        int i = 1;

        kernel_start = (unsigned long)&_text;
        kernel_end   = (unsigned long)&_etext;

        module_start = VMALLOC_START;
        module_end   = VMALLOC_END;

        if (!sp) {
                /*
                 * If we haven't specified a sane sp, fetch it..
                 */
                __asm__ __volatile__ (
                        "or     r15, r63, %0\n\t"
                        "getcon " __c17 ", %1\n\t"
                        : "=r" (module_start),
                          "=r" (module_end)
                );

                sp = (unsigned long *)module_start;
        }

        stack = sp;

        printk("\nCall Trace: ");

        while ((unsigned long)stack & (PAGE_SIZE - 1)) {
                unsigned long addr = *stack++;

                if ((addr >= kernel_start && addr < kernel_end) ||
                    (addr >= module_start && addr < module_end)) {
                        /* 
                         * Do a bit of formatting here.. on an 80 column
                         * display, 6 entries is the most we can deal with
                         * per-line, since each address will take up 13 spaces.
                         */
                        if (i && ((i % 6) == 0))
                                printk("\n       ");

                        printk("[<%08lx>] ", addr);
                        i++;
                }
        }

        printk("\n");
}

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

void dump_stack(void)
{
        show_task(NULL);
}

static void do_unhandled_exception(int trapnr, int signr, char *str, char *fn_name,
                unsigned long error_code, struct pt_regs *regs, struct task_struct *tsk)
{
        show_excp_regs(fn_name, trapnr, signr, regs);
        tsk->thread.error_code = error_code;
        tsk->thread.trap_no = trapnr;
        if (user_mode(regs)) force_sig(signr, tsk);
        die_if_no_fixup(str, regs, error_code);
}

static int read_opcode(unsigned long long pc, unsigned long *result_opcode)
{
        int get_user_error;
        unsigned long aligned_pc;
        unsigned long opcode;

        if ((pc & 3) == 1) {
                /* SHmedia */
                aligned_pc = pc & ~3;
                if (!access_ok(VERIFY_READ, aligned_pc, sizeof(unsigned long))) {
                        get_user_error = -EFAULT;
                } else {
                        get_user_error = __get_user(opcode, (unsigned long *)aligned_pc);
                        *result_opcode = opcode;
                }
                return get_user_error;
        } else if ((pc & 1) == 0) {
                /* SHcompact */
                /* TODO : provide handling for this. */
                return -EFAULT;
        } else {
                /* misaligned */
                return -EFAULT;
        }
}

static int address_is_sign_extended(__u64 a)
{
        __u64 b;
#if (NEFF == 32)        
        b = (__u64)(__s64)(__s32)(a & 0xffffffffUL);
        return (b == a) ? 1 : 0;
#else
#error "Sign extend check only works for NEFF==32"
#endif
}

static int generate_and_check_address(struct pt_regs *regs,
                                      __u32 opcode,
                                      int displacement_not_indexed,
                                      int width_shift,
                                      __u64 *address)
{
        /* return -1 for fault, 0 for OK */

        __u64 base_address, addr;
        int basereg;
        int do_as_user = user_mode(regs);
        
        basereg = (opcode >> 20) & 0x3f;
        base_address = regs->regs[basereg];
        if (displacement_not_indexed) {
                __s64 displacement;
                displacement = (opcode >> 10) & 0x3ff;
                displacement = ((displacement << 54) >> 54); /* sign extend */
                addr = (__u64)((__s64)base_address + (displacement << width_shift));
        } else {
                __u64 offset;
                int offsetreg;
                offsetreg = (opcode >> 10) & 0x3f;
                offset = regs->regs[offsetreg];
                addr = base_address + offset;
        }

        /* Check sign extended */
        if (!address_is_sign_extended(addr)) {
                return -1;
        }
        
#if defined(CONFIG_SH64_USER_MISALIGNED_FIXUP)
        /* Check accessible.  For misaligned access in the kernel, assume the
           address is always accessible (and if not, just fault when the
           load/store gets done.) */
        if (do_as_user) {
                if (addr >= TASK_SIZE) {
                        return -1;
                }
                /* Do access_ok check later - it depends on whether it's a load or a store. */
        }
#endif

        *address = addr;
        return 0;
}

/* Default value as for sh */
#if defined(CONFIG_SH64_USER_MISALIGNED_FIXUP)
static int user_mode_unaligned_fixup_count = 10;
static int user_mode_unaligned_fixup_enable = 1;
#endif

static int kernel_mode_unaligned_fixup_count = 32;

static void misaligned_kernel_word_load(__u64 address, int do_sign_extend, __u64 *result)
{
        unsigned short x;
        unsigned char *p, *q;
        p = (unsigned char *) (int) address;
        q = (unsigned char *) &x;
        q[0] = p[0];
        q[1] = p[1];

        if (do_sign_extend) {
                *result = (__u64)(__s64) *(short *) &x;
        } else {
                *result = (__u64) x;
        }
}

static void misaligned_kernel_word_store(__u64 address, __u64 value)
{
        unsigned short x;
        unsigned char *p, *q;
        p = (unsigned char *) (int) address;
        q = (unsigned char *) &x;

        x = (__u16) value;
        p[0] = q[0];
        p[1] = q[1];
}

static int misaligned_load(struct pt_regs *regs,
                           __u32 opcode,
                           int displacement_not_indexed,
                           int width_shift,
                           int do_sign_extend)
{
        /* Return -1 for a fault, 0 for OK */
        int error;
        int destreg;
        __u64 address;

        error = generate_and_check_address(regs, opcode, 
                        displacement_not_indexed, width_shift, &address);
        if (error < 0) {
                return error;
        }

        destreg = (opcode >> 4) & 0x3f;
#if defined(CONFIG_SH64_USER_MISALIGNED_FIXUP)
        if (user_mode(regs)) {
                __u64 buffer;
                
                if (!access_ok(VERIFY_READ, (unsigned long) address, 1UL<<width_shift)) {
                        return -1;
                }

                if (__copy_user(&buffer, (const void *)(int)address, (1 << width_shift)) > 0) {
                        return -1; /* fault */
                }
                switch (width_shift) {
                case 1:
                        if (do_sign_extend) {
                                regs->regs[destreg] = (__u64)(__s64) *(__s16 *) &buffer;
                        } else {
                                regs->regs[destreg] = (__u64) *(__u16 *) &buffer;
                        }
                        break;
                case 2:
                        regs->regs[destreg] = (__u64)(__s64) *(__s32 *) &buffer;
                        break;
                case 3:
                        regs->regs[destreg] = buffer;
                        break;
                default:
                        printk("Unexpected width_shift %d in misaligned_load, PC=%08lx\n", 
                                width_shift, (unsigned long) regs->pc);
                        break;
                }
        } else
#endif
        {
                /* kernel mode - we can take short cuts since if we fault, it's a genuine bug */
                __u64 lo, hi;

                switch (width_shift) {
                case 1:
                        misaligned_kernel_word_load(address, do_sign_extend, &regs->regs[destreg]);
                        break;
                case 2:
                        asm ("ldlo.l %1, 0, %0" : "=r" (lo) : "r" (address));
                        asm ("ldhi.l %1, 3, %0" : "=r" (hi) : "r" (address));
                        regs->regs[destreg] = lo | hi;
                        break;
                case 3:
                        asm ("ldlo.q %1, 0, %0" : "=r" (lo) : "r" (address));
                        asm ("ldhi.q %1, 7, %0" : "=r" (hi) : "r" (address));
                        regs->regs[destreg] = lo | hi;
                        break;

                default:
                        printk("Unexpected width_shift %d in misaligned_load, PC=%08lx\n", 
                                width_shift, (unsigned long) regs->pc);
                        break;
                }
        }

        return 0;

}

static int misaligned_store(struct pt_regs *regs,
                            __u32 opcode,
                            int displacement_not_indexed,
                            int width_shift)
{
        /* Return -1 for a fault, 0 for OK */
        int error;
        int srcreg;
        __u64 address;

        error = generate_and_check_address(regs, opcode, 
                        displacement_not_indexed, width_shift, &address);
        if (error < 0) {
                return error;
        }

        srcreg = (opcode >> 4) & 0x3f;
#if defined(CONFIG_SH64_USER_MISALIGNED_FIXUP)
        if (user_mode(regs)) {
                __u64 buffer;
                
                if (!access_ok(VERIFY_WRITE, (unsigned long) address, 1UL<<width_shift)) {
                        return -1;
                }

                switch (width_shift) {
                case 1:
                        *(__u16 *) &buffer = (__u16) regs->regs[srcreg];
                        break;
                case 2:
                        *(__u32 *) &buffer = (__u32) regs->regs[srcreg];
                        break;
                case 3:
                        buffer = regs->regs[srcreg];
                        break;
                default:
                        printk("Unexpected width_shift %d in misaligned_store, PC=%08lx\n", 
                                width_shift, (unsigned long) regs->pc);
                        break;
                }

                if (__copy_user((void *)(int)address, &buffer, (1 << width_shift)) > 0) {
                        return -1; /* fault */
                }
        } else
#endif
        {
                /* kernel mode - we can take short cuts since if we fault, it's a genuine bug */
                __u64 val = regs->regs[srcreg];

                switch (width_shift) {
                case 1:
                        misaligned_kernel_word_store(address, val);
                        break;
                case 2:
                        asm ("stlo.l %1, 0, %0" : : "r" (val), "r" (address));
                        asm ("sthi.l %1, 3, %0" : : "r" (val), "r" (address));
                        break;
                case 3:
                        asm ("stlo.q %1, 0, %0" : : "r" (val), "r" (address));
                        asm ("sthi.q %1, 7, %0" : : "r" (val), "r" (address));
                        break;

                default:
                        printk("Unexpected width_shift %d in misaligned_store, PC=%08lx\n", 
                                width_shift, (unsigned long) regs->pc);
                        break;
                }
        }

        return 0;

}

#if defined(CONFIG_SH64_USER_MISALIGNED_FIXUP)
/* Never need to fix up misaligned FPU accesses within the kernel since that's a real
   error. */
static int misaligned_fpu_load(struct pt_regs *regs,
                           __u32 opcode,
                           int displacement_not_indexed,
                           int width_shift,
                           int do_paired_load)
{
        /* Return -1 for a fault, 0 for OK */
        int error;
        int destreg;
        __u64 address;

        error = generate_and_check_address(regs, opcode, 
                        displacement_not_indexed, width_shift, &address);
        if (error < 0) {
                return error;
        }

        destreg = (opcode >> 4) & 0x3f;
        if (user_mode(regs)) {
                __u64 buffer;
                __u32 buflo, bufhi;
                
                if (!access_ok(VERIFY_READ, (unsigned long) address, 1UL<<width_shift)) {
                        return -1;
                }

                if (__copy_user(&buffer, (const void *)(int)address, (1 << width_shift)) > 0) {
                        return -1; /* fault */
                }
                /* 'current' may be the current owner of the FPU state, so
                   context switch the registers into memory so they can be
                   indexed by register number. */
                if (last_task_used_math == current) {
                        grab_fpu();
                        fpsave(&current->thread.fpu.hard);
                        release_fpu();
                        last_task_used_math = NULL;
                        regs->sr |= SR_FD;
                }

                buflo = *(__u32*) &buffer;
                bufhi = *(1 + (__u32*) &buffer);

                switch (width_shift) {
                case 2:
                        current->thread.fpu.hard.fp_regs[destreg] = buflo;
                        break;
                case 3:
                        if (do_paired_load) {
                                current->thread.fpu.hard.fp_regs[destreg] = buflo;
                                current->thread.fpu.hard.fp_regs[destreg+1] = bufhi;
                        } else {
#if defined(CONFIG_LITTLE_ENDIAN)
                                current->thread.fpu.hard.fp_regs[destreg] = bufhi;
                                current->thread.fpu.hard.fp_regs[destreg+1] = buflo;
#else
                                current->thread.fpu.hard.fp_regs[destreg] = buflo;
                                current->thread.fpu.hard.fp_regs[destreg+1] = bufhi;
#endif
                        }
                        break;
                default:
                        printk("Unexpected width_shift %d in misaligned_fpu_load, PC=%08lx\n", 
                                width_shift, (unsigned long) regs->pc);
                        break;
                }
                return 0;
        } else {
                die ("Misaligned FPU load inside kernel", regs, 0);
                return -1;
        }


}

static int misaligned_fpu_store(struct pt_regs *regs,
                           __u32 opcode,
                           int displacement_not_indexed,
                           int width_shift,
                           int do_paired_load)
{
        /* Return -1 for a fault, 0 for OK */
        int error;
        int srcreg;
        __u64 address;

        error = generate_and_check_address(regs, opcode, 
                        displacement_not_indexed, width_shift, &address);
        if (error < 0) {
                return error;
        }

        srcreg = (opcode >> 4) & 0x3f;
        if (user_mode(regs)) {
                __u64 buffer;
                /* Initialise these to NaNs. */
                __u32 buflo=0xffffffffUL, bufhi=0xffffffffUL;
                
                if (!access_ok(VERIFY_WRITE, (unsigned long) address, 1UL<<width_shift)) {
                        return -1;
                }

                /* 'current' may be the current owner of the FPU state, so
                   context switch the registers into memory so they can be
                   indexed by register number. */
                if (last_task_used_math == current) {
                        grab_fpu();
                        fpsave(&current->thread.fpu.hard);
                        release_fpu();
                        last_task_used_math = NULL;
                        regs->sr |= SR_FD;
                }

                switch (width_shift) {
                case 2:
                        buflo = current->thread.fpu.hard.fp_regs[srcreg];
                        break;
                case 3:
                        if (do_paired_load) {
                                buflo = current->thread.fpu.hard.fp_regs[srcreg];
                                bufhi = current->thread.fpu.hard.fp_regs[srcreg+1];
                        } else {
#if defined(CONFIG_LITTLE_ENDIAN)
                                bufhi = current->thread.fpu.hard.fp_regs[srcreg];
                                buflo = current->thread.fpu.hard.fp_regs[srcreg+1];
#else
                                buflo = current->thread.fpu.hard.fp_regs[srcreg];
                                bufhi = current->thread.fpu.hard.fp_regs[srcreg+1];
#endif
                        }
                        break;
                default:
                        printk("Unexpected width_shift %d in misaligned_fpu_store, PC=%08lx\n", 
                                width_shift, (unsigned long) regs->pc);
                        break;
                }
                
                *(__u32*) &buffer = buflo;
                *(1 + (__u32*) &buffer) = bufhi;
                if (__copy_user((void *)(int)address, &buffer, (1 << width_shift)) > 0) {
                        return -1; /* fault */
                }
                return 0;
        } else {
                die ("Misaligned FPU load inside kernel", regs, 0);
                return -1;
        }
}
#endif

static int misaligned_fixup(struct pt_regs *regs)
{
        unsigned long opcode;
        int error;
        int major, minor;

#if !defined(CONFIG_SH64_USER_MISALIGNED_FIXUP)
        /* Never fixup user mode misaligned accesses without this option enabled. */
        return -1;
#else
        if (!user_mode_unaligned_fixup_enable) return -1;
#endif

        error = read_opcode(regs->pc, &opcode);
        if (error < 0) {
                return error;
        }
        major = (opcode >> 26) & 0x3f;
        minor = (opcode >> 16) & 0xf;

#if defined(CONFIG_SH64_USER_MISALIGNED_FIXUP)
        if (user_mode(regs) && (user_mode_unaligned_fixup_count > 0)) {
                --user_mode_unaligned_fixup_count;
                /* Only do 'count' worth of these reports, to remove a potential DoS against syslog */
                printk("Fixing up unaligned userspace access in \"%s\" pid=%d pc=0x%08x ins=0x%08lx\n",
                       current->comm, current->pid, (__u32)regs->pc, opcode);
        } else
#endif
        if (!user_mode(regs) && (kernel_mode_unaligned_fixup_count > 0)) {
                --kernel_mode_unaligned_fixup_count;
                if (in_interrupt()) {
                        printk("Fixing up unaligned kernelspace access in interrupt pc=0x%08x ins=0x%08lx\n",
                               (__u32)regs->pc, opcode);
                } else {
                        printk("Fixing up unaligned kernelspace access in \"%s\" pid=%d pc=0x%08x ins=0x%08lx\n",
                               current->comm, current->pid, (__u32)regs->pc, opcode);
                }
        }

        
        switch (major) {
                case (0x84>>2): /* LD.W */
                        error = misaligned_load(regs, opcode, 1, 1, 1);
                        break;
                case (0xb0>>2): /* LD.UW */
                        error = misaligned_load(regs, opcode, 1, 1, 0);
                        break;
                case (0x88>>2): /* LD.L */
                        error = misaligned_load(regs, opcode, 1, 2, 1);
                        break;
                case (0x8c>>2): /* LD.Q */
                        error = misaligned_load(regs, opcode, 1, 3, 0);
                        break;

                case (0xa4>>2): /* ST.W */
                        error = misaligned_store(regs, opcode, 1, 1);
                        break;
                case (0xa8>>2): /* ST.L */
                        error = misaligned_store(regs, opcode, 1, 2);
                        break;
                case (0xac>>2): /* ST.Q */
                        error = misaligned_store(regs, opcode, 1, 3);
                        break;

                case (0x40>>2): /* indexed loads */
                        switch (minor) {
                                case 0x1: /* LDX.W */
                                        error = misaligned_load(regs, opcode, 0, 1, 1);
                                        break;
                                case 0x5: /* LDX.UW */
                                        error = misaligned_load(regs, opcode, 0, 1, 0);
                                        break;
                                case 0x2: /* LDX.L */
                                        error = misaligned_load(regs, opcode, 0, 2, 1);
                                        break;
                                case 0x3: /* LDX.Q */
                                        error = misaligned_load(regs, opcode, 0, 3, 0);
                                        break;
                                default:
                                        error = -1;
                                        break;
                        }
                        break;

                case (0x60>>2): /* indexed stores */
                        switch (minor) {
                                case 0x1: /* STX.W */
                                        error = misaligned_store(regs, opcode, 0, 1);
                                        break;
                                case 0x2: /* STX.L */
                                        error = misaligned_store(regs, opcode, 0, 2);
                                        break;
                                case 0x3: /* STX.Q */
                                        error = misaligned_store(regs, opcode, 0, 3);
                                        break;
                                default:
                                        error = -1;
                                        break;
                        }
                        break;

#if defined(CONFIG_SH64_USER_MISALIGNED_FIXUP)
                case (0x94>>2): /* FLD.S */
                        error = misaligned_fpu_load(regs, opcode, 1, 2, 0);
                        break;
                case (0x98>>2): /* FLD.P */
                        error = misaligned_fpu_load(regs, opcode, 1, 3, 1);
                        break;
                case (0x9c>>2): /* FLD.D */
                        error = misaligned_fpu_load(regs, opcode, 1, 3, 0);
                        break;
                case (0x1c>>2): /* floating indexed loads */
                        switch (minor) {
                        case 0x8: /* FLDX.S */
                                error = misaligned_fpu_load(regs, opcode, 0, 2, 0);
                                break;
                        case 0xd: /* FLDX.P */
                                error = misaligned_fpu_load(regs, opcode, 0, 3, 1);
                                break;
                        case 0x9: /* FLDX.D */
                                error = misaligned_fpu_load(regs, opcode, 0, 3, 0);
                                break;
                        default:
                                error = -1;
                                break;
                        }
                        break;
                case (0xb4>>2): /* FLD.S */
                        error = misaligned_fpu_store(regs, opcode, 1, 2, 0);
                        break;
                case (0xb8>>2): /* FLD.P */
                        error = misaligned_fpu_store(regs, opcode, 1, 3, 1);
                        break;
                case (0xbc>>2): /* FLD.D */
                        error = misaligned_fpu_store(regs, opcode, 1, 3, 0);
                        break;
                case (0x3c>>2): /* floating indexed stores */
                        switch (minor) {
                        case 0x8: /* FSTX.S */
                                error = misaligned_fpu_store(regs, opcode, 0, 2, 0);
                                break;
                        case 0xd: /* FSTX.P */
                                error = misaligned_fpu_store(regs, opcode, 0, 3, 1);
                                break;
                        case 0x9: /* FSTX.D */
                                error = misaligned_fpu_store(regs, opcode, 0, 3, 0);
                                break;
                        default:
                                error = -1;
                                break;
                        }
                        break;
#endif

                default:
                        /* Fault */
                        error = -1;
                        break;
        }

        if (error < 0) {
                return error;
        } else {
                regs->pc += 4; /* Skip the instruction that's just been emulated */
                return 0;
        }

}

static ctl_table unaligned_table[] = {
        {1, "kernel_reports", &kernel_mode_unaligned_fixup_count,
                sizeof(int), 0644, NULL, &proc_dointvec},
#if defined(CONFIG_SH64_USER_MISALIGNED_FIXUP)
        {2, "user_reports", &user_mode_unaligned_fixup_count,
                sizeof(int), 0644, NULL, &proc_dointvec},
        {3, "user_enable", &user_mode_unaligned_fixup_enable,
                sizeof(int), 0644, NULL, &proc_dointvec},
#endif
        {0}
};

static ctl_table unaligned_root[] = {
        {1, "unaligned_fixup", NULL, 0, 0555, unaligned_table},
        {0}
};

static ctl_table sh64_root[] = {
        {1, "sh64", NULL, 0, 0555, unaligned_root},
        {0}
};
static struct ctl_table_header *sysctl_header;
static int __init init_sysctl(void)
{
        sysctl_header = register_sysctl_table(sh64_root, 0);
        return 0;
}

__initcall(init_sysctl);