/*
 * Copyright 2013 Tilera Corporation. All Rights Reserved.
 *
 *   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, version 2.
 *
 *   This program is distributed in the hope that it will be useful, but
 *   WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
 *   NON INFRINGEMENT.  See the GNU General Public License for
 *   more details.
 *
 * A code-rewriter that handles unaligned exception.
 */

#include <linux/smp.h>
#include <linux/ptrace.h>
#include <linux/slab.h>
#include <linux/thread_info.h>
#include <linux/uaccess.h>
#include <linux/mman.h>
#include <linux/types.h>
#include <linux/err.h>
#include <linux/module.h>
#include <linux/compat.h>
#include <linux/prctl.h>
#include <asm/cacheflush.h>
#include <asm/traps.h>
#include <asm/uaccess.h>
#include <asm/unaligned.h>
#include <arch/abi.h>
#include <arch/spr_def.h>
#include <arch/opcode.h>


/*
 * This file handles unaligned exception for tile-Gx. The tilepro's unaligned
 * exception is supported out of single_step.c
 */

int unaligned_printk;

static int __init setup_unaligned_printk(char *str)
{
        long val;
        if (kstrtol(str, 0, &val) != 0)
                return 0;
        unaligned_printk = val;
        pr_info("Printk for each unaligned data accesses is %s\n",
                unaligned_printk ? "enabled" : "disabled");
        return 1;
}
__setup("unaligned_printk=", setup_unaligned_printk);

unsigned int unaligned_fixup_count;

#ifdef __tilegx__

/*
 * Unalign data jit fixup code fragement. Reserved space is 128 bytes.
 * The 1st 64-bit word saves fault PC address, 2nd word is the fault
 * instruction bundle followed by 14 JIT bundles.
 */

struct unaligned_jit_fragment {
        unsigned long       pc;
        tilegx_bundle_bits  bundle;
        tilegx_bundle_bits  insn[14];
};

/*
 * Check if a nop or fnop at bundle's pipeline X0.
 */

static bool is_bundle_x0_nop(tilegx_bundle_bits bundle)
{
        return (((get_UnaryOpcodeExtension_X0(bundle) ==
                  NOP_UNARY_OPCODE_X0) &&
                 (get_RRROpcodeExtension_X0(bundle) ==
                  UNARY_RRR_0_OPCODE_X0) &&
                 (get_Opcode_X0(bundle) ==
                  RRR_0_OPCODE_X0)) ||
                ((get_UnaryOpcodeExtension_X0(bundle) ==
                  FNOP_UNARY_OPCODE_X0) &&
                 (get_RRROpcodeExtension_X0(bundle) ==
                  UNARY_RRR_0_OPCODE_X0) &&
                 (get_Opcode_X0(bundle) ==
                  RRR_0_OPCODE_X0)));
}

/*
 * Check if nop or fnop at bundle's pipeline X1.
 */

static bool is_bundle_x1_nop(tilegx_bundle_bits bundle)
{
        return (((get_UnaryOpcodeExtension_X1(bundle) ==
                  NOP_UNARY_OPCODE_X1) &&
                 (get_RRROpcodeExtension_X1(bundle) ==
                  UNARY_RRR_0_OPCODE_X1) &&
                 (get_Opcode_X1(bundle) ==
                  RRR_0_OPCODE_X1)) ||
                ((get_UnaryOpcodeExtension_X1(bundle) ==
                  FNOP_UNARY_OPCODE_X1) &&
                 (get_RRROpcodeExtension_X1(bundle) ==
                  UNARY_RRR_0_OPCODE_X1) &&
                 (get_Opcode_X1(bundle) ==
                  RRR_0_OPCODE_X1)));
}

/*
 * Check if nop or fnop at bundle's Y0 pipeline.
 */

static bool is_bundle_y0_nop(tilegx_bundle_bits bundle)
{
        return (((get_UnaryOpcodeExtension_Y0(bundle) ==
                  NOP_UNARY_OPCODE_Y0) &&
                 (get_RRROpcodeExtension_Y0(bundle) ==
                  UNARY_RRR_1_OPCODE_Y0) &&
                 (get_Opcode_Y0(bundle) ==
                  RRR_1_OPCODE_Y0)) ||
                ((get_UnaryOpcodeExtension_Y0(bundle) ==
                  FNOP_UNARY_OPCODE_Y0) &&
                 (get_RRROpcodeExtension_Y0(bundle) ==
                  UNARY_RRR_1_OPCODE_Y0) &&
                 (get_Opcode_Y0(bundle) ==
                  RRR_1_OPCODE_Y0)));
}

/*
 * Check if nop or fnop at bundle's pipeline Y1.
 */

static bool is_bundle_y1_nop(tilegx_bundle_bits bundle)
{
        return (((get_UnaryOpcodeExtension_Y1(bundle) ==
                  NOP_UNARY_OPCODE_Y1) &&
                 (get_RRROpcodeExtension_Y1(bundle) ==
                  UNARY_RRR_1_OPCODE_Y1) &&
                 (get_Opcode_Y1(bundle) ==
                  RRR_1_OPCODE_Y1)) ||
                ((get_UnaryOpcodeExtension_Y1(bundle) ==
                  FNOP_UNARY_OPCODE_Y1) &&
                 (get_RRROpcodeExtension_Y1(bundle) ==
                  UNARY_RRR_1_OPCODE_Y1) &&
                 (get_Opcode_Y1(bundle) ==
                  RRR_1_OPCODE_Y1)));
}

/*
 * Test if a bundle's y0 and y1 pipelines are both nop or fnop.
 */

static bool is_y0_y1_nop(tilegx_bundle_bits bundle)
{
        return is_bundle_y0_nop(bundle) && is_bundle_y1_nop(bundle);
}

/*
 * Test if a bundle's x0 and x1 pipelines are both nop or fnop.
 */

static bool is_x0_x1_nop(tilegx_bundle_bits bundle)
{
        return is_bundle_x0_nop(bundle) && is_bundle_x1_nop(bundle);
}

/*
 * Find the destination, source registers of fault unalign access instruction
 * at X1 or Y2. Also, allocate up to 3 scratch registers clob1, clob2 and
 * clob3, which are guaranteed different from any register used in the fault
 * bundle. r_alias is used to return if the other instructions other than the
 * unalign load/store shares same register with ra, rb and rd.
 */

static void find_regs(tilegx_bundle_bits bundle, uint64_t *rd, uint64_t *ra,
                      uint64_t *rb, uint64_t *clob1, uint64_t *clob2,
                      uint64_t *clob3, bool *r_alias)
{
        int i;
        uint64_t reg;
        uint64_t reg_map = 0, alias_reg_map = 0, map;
        bool alias = false;

        /*
         * Parse fault bundle, find potential used registers and mark
         * corresponding bits in reg_map and alias_map. These 2 bit maps
         * are used to find the scratch registers and determine if there
         * is register alias.
         */
        if (bundle & TILEGX_BUNDLE_MODE_MASK) {  /* Y Mode Bundle. */

                reg = get_SrcA_Y2(bundle);
                reg_map |= 1ULL << reg;
                *ra = reg;
                reg = get_SrcBDest_Y2(bundle);
                reg_map |= 1ULL << reg;

                if (rd) {
                        /* Load. */
                        *rd = reg;
                        alias_reg_map = (1ULL << *rd) | (1ULL << *ra);
                } else {
                        /* Store. */
                        *rb = reg;
                        alias_reg_map = (1ULL << *ra) | (1ULL << *rb);
                }

                if (!is_bundle_y1_nop(bundle)) {
                        reg = get_SrcA_Y1(bundle);
                        reg_map |= (1ULL << reg);
                        map = (1ULL << reg);

                        reg = get_SrcB_Y1(bundle);
                        reg_map |= (1ULL << reg);
                        map |= (1ULL << reg);

                        reg = get_Dest_Y1(bundle);
                        reg_map |= (1ULL << reg);
                        map |= (1ULL << reg);

                        if (map & alias_reg_map)
                                alias = true;
                }

                if (!is_bundle_y0_nop(bundle)) {
                        reg = get_SrcA_Y0(bundle);
                        reg_map |= (1ULL << reg);
                        map = (1ULL << reg);

                        reg = get_SrcB_Y0(bundle);
                        reg_map |= (1ULL << reg);
                        map |= (1ULL << reg);

                        reg = get_Dest_Y0(bundle);
                        reg_map |= (1ULL << reg);
                        map |= (1ULL << reg);

                        if (map & alias_reg_map)
                                alias = true;
                }
        } else  { /* X Mode Bundle. */

                reg = get_SrcA_X1(bundle);
                reg_map |= (1ULL << reg);
                *ra = reg;
                if (rd) {
                        /* Load. */
                        reg = get_Dest_X1(bundle);
                        reg_map |= (1ULL << reg);
                        *rd = reg;
                        alias_reg_map = (1ULL << *rd) | (1ULL << *ra);
                } else {
                        /* Store. */
                        reg = get_SrcB_X1(bundle);
                        reg_map |= (1ULL << reg);
                        *rb = reg;
                        alias_reg_map = (1ULL << *ra) | (1ULL << *rb);
                }

                if (!is_bundle_x0_nop(bundle)) {
                        reg = get_SrcA_X0(bundle);
                        reg_map |= (1ULL << reg);
                        map = (1ULL << reg);

                        reg = get_SrcB_X0(bundle);
                        reg_map |= (1ULL << reg);
                        map |= (1ULL << reg);

                        reg = get_Dest_X0(bundle);
                        reg_map |= (1ULL << reg);
                        map |= (1ULL << reg);

                        if (map & alias_reg_map)
                                alias = true;
                }
        }

        /*
         * "alias" indicates if the unalign access registers have collision
         * with others in the same bundle. We jsut simply test all register
         * operands case (RRR), ignored the case with immidate. If a bundle
         * has no register alias, we may do fixup in a simple or fast manner.
         * So if an immidata field happens to hit with a register, we may end
         * up fall back to the generic handling.
         */

        *r_alias = alias;

        /* Flip bits on reg_map. */
        reg_map ^= -1ULL;

        /* Scan reg_map lower 54(TREG_SP) bits to find 3 set bits. */
        for (i = 0; i < TREG_SP; i++) {
                if (reg_map & (0x1ULL << i)) {
                        if (*clob1 == -1) {
                                *clob1 = i;
                        } else if (*clob2 == -1) {
                                *clob2 = i;
                        } else if (*clob3 == -1) {
                                *clob3 = i;
                                return;
                        }
                }
        }
}

/*
 * Sanity check for register ra, rb, rd, clob1/2/3. Return true if any of them
 * is unexpected.
 */

static bool check_regs(uint64_t rd, uint64_t ra, uint64_t rb,
                       uint64_t clob1, uint64_t clob2,  uint64_t clob3)
{
        bool unexpected = false;
        if ((ra >= 56) && (ra != TREG_ZERO))
                unexpected = true;

        if ((clob1 >= 56) || (clob2 >= 56) || (clob3 >= 56))
                unexpected = true;

        if (rd != -1) {
                if ((rd >= 56) && (rd != TREG_ZERO))
                        unexpected = true;
        } else {
                if ((rb >= 56) && (rb != TREG_ZERO))
                        unexpected = true;
        }
        return unexpected;
}


#define  GX_INSN_X0_MASK   ((1ULL << 31) - 1)
#define  GX_INSN_X1_MASK   (((1ULL << 31) - 1) << 31)
#define  GX_INSN_Y0_MASK   ((0xFULL << 27) | (0xFFFFFULL))
#define  GX_INSN_Y1_MASK   (GX_INSN_Y0_MASK << 31)
#define  GX_INSN_Y2_MASK   ((0x7FULL << 51) | (0x7FULL << 20))

#ifdef __LITTLE_ENDIAN
#define  GX_INSN_BSWAP(_bundle_)    (_bundle_)
#else
#define  GX_INSN_BSWAP(_bundle_)    swab64(_bundle_)
#endif /* __LITTLE_ENDIAN */

/*
 * __JIT_CODE(.) creates template bundles in .rodata.unalign_data section.
 * The corresponding static function jix_x#_###(.) generates partial or
 * whole bundle based on the template and given arguments.
 */

#define __JIT_CODE(_X_)                                         \
        asm (".pushsection .rodata.unalign_data, \"a\"\n"       \
             _X_"\n"                                            \
             ".popsection\n")

__JIT_CODE("__unalign_jit_x1_mtspr:   {mtspr 0,  r0}");
static tilegx_bundle_bits jit_x1_mtspr(int spr, int reg)
{
        extern  tilegx_bundle_bits __unalign_jit_x1_mtspr;
        return (GX_INSN_BSWAP(__unalign_jit_x1_mtspr) & GX_INSN_X1_MASK) |
                create_MT_Imm14_X1(spr) | create_SrcA_X1(reg);
}

__JIT_CODE("__unalign_jit_x1_mfspr:   {mfspr r0, 0}");
static tilegx_bundle_bits  jit_x1_mfspr(int reg, int spr)
{
        extern  tilegx_bundle_bits __unalign_jit_x1_mfspr;
        return (GX_INSN_BSWAP(__unalign_jit_x1_mfspr) & GX_INSN_X1_MASK) |
                create_MF_Imm14_X1(spr) | create_Dest_X1(reg);
}

__JIT_CODE("__unalign_jit_x0_addi:   {addi  r0, r0, 0; iret}");
static tilegx_bundle_bits  jit_x0_addi(int rd, int ra, int imm8)
{
        extern  tilegx_bundle_bits __unalign_jit_x0_addi;
        return (GX_INSN_BSWAP(__unalign_jit_x0_addi) & GX_INSN_X0_MASK) |
                create_Dest_X0(rd) | create_SrcA_X0(ra) |
                create_Imm8_X0(imm8);
}

__JIT_CODE("__unalign_jit_x1_ldna:   {ldna  r0, r0}");
static tilegx_bundle_bits  jit_x1_ldna(int rd, int ra)
{
        extern  tilegx_bundle_bits __unalign_jit_x1_ldna;
        return (GX_INSN_BSWAP(__unalign_jit_x1_ldna) &  GX_INSN_X1_MASK) |
                create_Dest_X1(rd) | create_SrcA_X1(ra);
}

__JIT_CODE("__unalign_jit_x0_dblalign:   {dblalign r0, r0 ,r0}");
static tilegx_bundle_bits  jit_x0_dblalign(int rd, int ra, int rb)
{
        extern  tilegx_bundle_bits __unalign_jit_x0_dblalign;
        return (GX_INSN_BSWAP(__unalign_jit_x0_dblalign) & GX_INSN_X0_MASK) |
                create_Dest_X0(rd) | create_SrcA_X0(ra) |
                create_SrcB_X0(rb);
}

__JIT_CODE("__unalign_jit_x1_iret:   {iret}");
static tilegx_bundle_bits  jit_x1_iret(void)
{
        extern  tilegx_bundle_bits __unalign_jit_x1_iret;
        return GX_INSN_BSWAP(__unalign_jit_x1_iret) & GX_INSN_X1_MASK;
}

__JIT_CODE("__unalign_jit_x01_fnop:   {fnop;fnop}");
static tilegx_bundle_bits  jit_x0_fnop(void)
{
        extern  tilegx_bundle_bits __unalign_jit_x01_fnop;
        return GX_INSN_BSWAP(__unalign_jit_x01_fnop) & GX_INSN_X0_MASK;
}

static tilegx_bundle_bits  jit_x1_fnop(void)
{
        extern  tilegx_bundle_bits __unalign_jit_x01_fnop;
        return GX_INSN_BSWAP(__unalign_jit_x01_fnop) & GX_INSN_X1_MASK;
}

__JIT_CODE("__unalign_jit_y2_dummy:   {fnop; fnop; ld zero, sp}");
static tilegx_bundle_bits  jit_y2_dummy(void)
{
        extern  tilegx_bundle_bits __unalign_jit_y2_dummy;
        return GX_INSN_BSWAP(__unalign_jit_y2_dummy) & GX_INSN_Y2_MASK;
}

static tilegx_bundle_bits  jit_y1_fnop(void)
{
        extern  tilegx_bundle_bits __unalign_jit_y2_dummy;
        return GX_INSN_BSWAP(__unalign_jit_y2_dummy) & GX_INSN_Y1_MASK;
}

__JIT_CODE("__unalign_jit_x1_st1_add:  {st1_add r1, r0, 0}");
static tilegx_bundle_bits  jit_x1_st1_add(int ra, int rb, int imm8)
{
        extern  tilegx_bundle_bits __unalign_jit_x1_st1_add;
        return (GX_INSN_BSWAP(__unalign_jit_x1_st1_add) &
                (~create_SrcA_X1(-1)) &
                GX_INSN_X1_MASK) | create_SrcA_X1(ra) |
                create_SrcB_X1(rb) | create_Dest_Imm8_X1(imm8);
}

__JIT_CODE("__unalign_jit_x1_st:  {crc32_8 r1, r0, r0; st  r0, r0}");
static tilegx_bundle_bits  jit_x1_st(int ra, int rb)
{
        extern  tilegx_bundle_bits __unalign_jit_x1_st;
        return (GX_INSN_BSWAP(__unalign_jit_x1_st) & GX_INSN_X1_MASK) |
                create_SrcA_X1(ra) | create_SrcB_X1(rb);
}

__JIT_CODE("__unalign_jit_x1_st_add:  {st_add  r1, r0, 0}");
static tilegx_bundle_bits  jit_x1_st_add(int ra, int rb, int imm8)
{
        extern  tilegx_bundle_bits __unalign_jit_x1_st_add;
        return (GX_INSN_BSWAP(__unalign_jit_x1_st_add) &
                (~create_SrcA_X1(-1)) &
                GX_INSN_X1_MASK) | create_SrcA_X1(ra) |
                create_SrcB_X1(rb) | create_Dest_Imm8_X1(imm8);
}

__JIT_CODE("__unalign_jit_x1_ld:  {crc32_8 r1, r0, r0; ld  r0, r0}");
static tilegx_bundle_bits  jit_x1_ld(int rd, int ra)
{
        extern  tilegx_bundle_bits __unalign_jit_x1_ld;
        return (GX_INSN_BSWAP(__unalign_jit_x1_ld) & GX_INSN_X1_MASK) |
                create_Dest_X1(rd) | create_SrcA_X1(ra);
}

__JIT_CODE("__unalign_jit_x1_ld_add:  {ld_add  r1, r0, 0}");
static tilegx_bundle_bits  jit_x1_ld_add(int rd, int ra, int imm8)
{
        extern  tilegx_bundle_bits __unalign_jit_x1_ld_add;
        return (GX_INSN_BSWAP(__unalign_jit_x1_ld_add) &
                (~create_Dest_X1(-1)) &
                GX_INSN_X1_MASK) | create_Dest_X1(rd) |
                create_SrcA_X1(ra) | create_Imm8_X1(imm8);
}

__JIT_CODE("__unalign_jit_x0_bfexts:  {bfexts r0, r0, 0, 0}");
static tilegx_bundle_bits  jit_x0_bfexts(int rd, int ra, int bfs, int bfe)
{
        extern  tilegx_bundle_bits __unalign_jit_x0_bfexts;
        return (GX_INSN_BSWAP(__unalign_jit_x0_bfexts) &
                GX_INSN_X0_MASK) |
                create_Dest_X0(rd) | create_SrcA_X0(ra) |
                create_BFStart_X0(bfs) | create_BFEnd_X0(bfe);
}

__JIT_CODE("__unalign_jit_x0_bfextu:  {bfextu r0, r0, 0, 0}");
static tilegx_bundle_bits  jit_x0_bfextu(int rd, int ra, int bfs, int bfe)
{
        extern  tilegx_bundle_bits __unalign_jit_x0_bfextu;
        return (GX_INSN_BSWAP(__unalign_jit_x0_bfextu) &
                GX_INSN_X0_MASK) |
                create_Dest_X0(rd) | create_SrcA_X0(ra) |
                create_BFStart_X0(bfs) | create_BFEnd_X0(bfe);
}

__JIT_CODE("__unalign_jit_x1_addi:  {bfextu r1, r1, 0, 0; addi r0, r0, 0}");
static tilegx_bundle_bits  jit_x1_addi(int rd, int ra, int imm8)
{
        extern  tilegx_bundle_bits __unalign_jit_x1_addi;
        return (GX_INSN_BSWAP(__unalign_jit_x1_addi) & GX_INSN_X1_MASK) |
                create_Dest_X1(rd) | create_SrcA_X1(ra) |
                create_Imm8_X1(imm8);
}

__JIT_CODE("__unalign_jit_x0_shrui:  {shrui r0, r0, 0; iret}");
static tilegx_bundle_bits  jit_x0_shrui(int rd, int ra, int imm6)
{
        extern  tilegx_bundle_bits __unalign_jit_x0_shrui;
        return (GX_INSN_BSWAP(__unalign_jit_x0_shrui) &
                GX_INSN_X0_MASK) |
                create_Dest_X0(rd) | create_SrcA_X0(ra) |
                create_ShAmt_X0(imm6);
}

__JIT_CODE("__unalign_jit_x0_rotli:  {rotli r0, r0, 0; iret}");
static tilegx_bundle_bits  jit_x0_rotli(int rd, int ra, int imm6)
{
        extern  tilegx_bundle_bits __unalign_jit_x0_rotli;
        return (GX_INSN_BSWAP(__unalign_jit_x0_rotli) &
                GX_INSN_X0_MASK) |
                create_Dest_X0(rd) | create_SrcA_X0(ra) |
                create_ShAmt_X0(imm6);
}

__JIT_CODE("__unalign_jit_x1_bnezt:  {bnezt r0, __unalign_jit_x1_bnezt}");
static tilegx_bundle_bits  jit_x1_bnezt(int ra, int broff)
{
        extern  tilegx_bundle_bits __unalign_jit_x1_bnezt;
        return (GX_INSN_BSWAP(__unalign_jit_x1_bnezt) &
                GX_INSN_X1_MASK) |
                create_SrcA_X1(ra) | create_BrOff_X1(broff);
}

#undef __JIT_CODE

/*
 * This function generates unalign fixup JIT.
 *
 * We first find unalign load/store instruction's destination, source
 * registers: ra, rb and rd. and 3 scratch registers by calling
 * find_regs(...). 3 scratch clobbers should not alias with any register
 * used in the fault bundle. Then analyze the fault bundle to determine
 * if it's a load or store, operand width, branch or address increment etc.
 * At last generated JIT is copied into JIT code area in user space.
 */

static
void jit_bundle_gen(struct pt_regs *regs, tilegx_bundle_bits bundle,
                    int align_ctl)
{
        struct thread_info *info = current_thread_info();
        struct unaligned_jit_fragment frag;
        struct unaligned_jit_fragment *jit_code_area;
        tilegx_bundle_bits bundle_2 = 0;
        /* If bundle_2_enable = false, bundle_2 is fnop/nop operation. */
        bool     bundle_2_enable = true;
        uint64_t ra = -1, rb = -1, rd = -1, clob1 = -1, clob2 = -1, clob3 = -1;
        /*
         * Indicate if the unalign access
         * instruction's registers hit with
         * others in the same bundle.
         */
        bool     alias = false;
        bool     load_n_store = true;
        bool     load_store_signed = false;
        unsigned int  load_store_size = 8;
        bool     y1_br = false;  /* True, for a branch in same bundle at Y1.*/
        int      y1_br_reg = 0;
        /* True for link operation. i.e. jalr or lnk at Y1 */
        bool     y1_lr = false;
        int      y1_lr_reg = 0;
        bool     x1_add = false;/* True, for load/store ADD instruction at X1*/
        int      x1_add_imm8 = 0;
        bool     unexpected = false;
        int      n = 0, k;

        jit_code_area =
                (struct unaligned_jit_fragment *)(info->unalign_jit_base);

        memset((void *)&frag, 0, sizeof(frag));

        /* 0: X mode, Otherwise: Y mode. */
        if (bundle & TILEGX_BUNDLE_MODE_MASK) {
                unsigned int mod, opcode;

                if (get_Opcode_Y1(bundle) == RRR_1_OPCODE_Y1 &&
                    get_RRROpcodeExtension_Y1(bundle) ==
                    UNARY_RRR_1_OPCODE_Y1) {

                        opcode = get_UnaryOpcodeExtension_Y1(bundle);

                        /*
                         * Test "jalr", "jalrp", "jr", "jrp" instruction at Y1
                         * pipeline.
                         */
                        switch (opcode) {
                        case JALR_UNARY_OPCODE_Y1:
                        case JALRP_UNARY_OPCODE_Y1:
                                y1_lr = true;
                                y1_lr_reg = 55; /* Link register. */
                                /* FALLTHROUGH */
                        case JR_UNARY_OPCODE_Y1:
                        case JRP_UNARY_OPCODE_Y1:
                                y1_br = true;
                                y1_br_reg = get_SrcA_Y1(bundle);
                                break;
                        case LNK_UNARY_OPCODE_Y1:
                                /* "lnk" at Y1 pipeline. */
                                y1_lr = true;
                                y1_lr_reg = get_Dest_Y1(bundle);
                                break;
                        }
                }

                opcode = get_Opcode_Y2(bundle);
                mod = get_Mode(bundle);

                /*
                 *  bundle_2 is bundle after making Y2 as a dummy operation
                 *  - ld zero, sp
                 */
                bundle_2 = (bundle & (~GX_INSN_Y2_MASK)) | jit_y2_dummy();

                /* Make Y1 as fnop if Y1 is a branch or lnk operation. */
                if (y1_br || y1_lr) {
                        bundle_2 &= ~(GX_INSN_Y1_MASK);
                        bundle_2 |= jit_y1_fnop();
                }

                if (is_y0_y1_nop(bundle_2))
                        bundle_2_enable = false;

                if (mod == MODE_OPCODE_YC2) {
                        /* Store. */
                        load_n_store = false;
                        load_store_size = 1 << opcode;
                        load_store_signed = false;
                        find_regs(bundle, 0, &ra, &rb, &clob1, &clob2,
                                  &clob3, &alias);
                        if (load_store_size > 8)
                                unexpected = true;
                } else {
                        /* Load. */
                        load_n_store = true;
                        if (mod == MODE_OPCODE_YB2) {
                                switch (opcode) {
                                case LD_OPCODE_Y2:
                                        load_store_signed = false;
                                        load_store_size = 8;
                                        break;
                                case LD4S_OPCODE_Y2:
                                        load_store_signed = true;
                                        load_store_size = 4;
                                        break;
                                case LD4U_OPCODE_Y2:
                                        load_store_signed = false;
                                        load_store_size = 4;
                                        break;
                                default:
                                        unexpected = true;
                                }
                        } else if (mod == MODE_OPCODE_YA2) {
                                if (opcode == LD2S_OPCODE_Y2) {
                                        load_store_signed = true;
                                        load_store_size = 2;
                                } else if (opcode == LD2U_OPCODE_Y2) {
                                        load_store_signed = false;
                                        load_store_size = 2;
                                } else
                                        unexpected = true;
                        } else
                                unexpected = true;
                        find_regs(bundle, &rd, &ra, &rb, &clob1, &clob2,
                                  &clob3, &alias);
                }
        } else {
                unsigned int opcode;

                /* bundle_2 is bundle after making X1 as "fnop". */
                bundle_2 = (bundle & (~GX_INSN_X1_MASK)) | jit_x1_fnop();

                if (is_x0_x1_nop(bundle_2))
                        bundle_2_enable = false;

                if (get_Opcode_X1(bundle) == RRR_0_OPCODE_X1) {
                        opcode = get_UnaryOpcodeExtension_X1(bundle);

                        if (get_RRROpcodeExtension_X1(bundle) ==
                            UNARY_RRR_0_OPCODE_X1) {
                                load_n_store = true;
                                find_regs(bundle, &rd, &ra, &rb, &clob1,
                                          &clob2, &clob3, &alias);

                                switch (opcode) {
                                case LD_UNARY_OPCODE_X1:
                                        load_store_signed = false;
                                        load_store_size = 8;
                                        break;
                                case LD4S_UNARY_OPCODE_X1:
                                        load_store_signed = true;
                                        /* FALLTHROUGH */
                                case LD4U_UNARY_OPCODE_X1:
                                        load_store_size = 4;
                                        break;

                                case LD2S_UNARY_OPCODE_X1:
                                        load_store_signed = true;
                                        /* FALLTHROUGH */
                                case LD2U_UNARY_OPCODE_X1:
                                        load_store_size = 2;
                                        break;
                                default:
                                        unexpected = true;
                                }
                        } else {
                                load_n_store = false;
                                load_store_signed = false;
                                find_regs(bundle, 0, &ra, &rb,
                                          &clob1, &clob2, &clob3,
                                          &alias);

                                opcode = get_RRROpcodeExtension_X1(bundle);
                                switch (opcode) {
                                case ST_RRR_0_OPCODE_X1:
                                        load_store_size = 8;
                                        break;
                                case ST4_RRR_0_OPCODE_X1:
                                        load_store_size = 4;
                                        break;
                                case ST2_RRR_0_OPCODE_X1:
                                        load_store_size = 2;
                                        break;
                                default:
                                        unexpected = true;
                                }
                        }
                } else if (get_Opcode_X1(bundle) == IMM8_OPCODE_X1) {
                        load_n_store = true;
                        opcode = get_Imm8OpcodeExtension_X1(bundle);
                        switch (opcode) {
                        case LD_ADD_IMM8_OPCODE_X1:
                                load_store_size = 8;
                                break;

                        case LD4S_ADD_IMM8_OPCODE_X1:
                                load_store_signed = true;
                                /* FALLTHROUGH */
                        case LD4U_ADD_IMM8_OPCODE_X1:
                                load_store_size = 4;
                                break;

                        case LD2S_ADD_IMM8_OPCODE_X1:
                                load_store_signed = true;
                                /* FALLTHROUGH */
                        case LD2U_ADD_IMM8_OPCODE_X1:
                                load_store_size = 2;
                                break;

                        case ST_ADD_IMM8_OPCODE_X1:
                                load_n_store = false;
                                load_store_size = 8;
                                break;
                        case ST4_ADD_IMM8_OPCODE_X1:
                                load_n_store = false;
                                load_store_size = 4;
                                break;
                        case ST2_ADD_IMM8_OPCODE_X1:
                                load_n_store = false;
                                load_store_size = 2;
                                break;
                        default:
                                unexpected = true;
                        }

                        if (!unexpected) {
                                x1_add = true;
                                if (load_n_store)
                                        x1_add_imm8 = get_Imm8_X1(bundle);
                                else
                                        x1_add_imm8 = get_Dest_Imm8_X1(bundle);
                        }

                        find_regs(bundle, load_n_store ? (&rd) : NULL,
                                  &ra, &rb, &clob1, &clob2, &clob3, &alias);
                } else
                        unexpected = true;
        }

        /*
         * Some sanity check for register numbers extracted from fault bundle.
         */
        if (check_regs(rd, ra, rb, clob1, clob2, clob3) == true)
                unexpected = true;

        /* Give warning if register ra has an aligned address. */
        if (!unexpected)
                WARN_ON(!((load_store_size - 1) & (regs->regs[ra])));


        /*
         * Fault came from kernel space, here we only need take care of
         * unaligned "get_user/put_user" macros defined in "uaccess.h".
         * Basically, we will handle bundle like this:
         * {ld/2u/4s rd, ra; movei rx, 0} or {st/2/4 ra, rb; movei rx, 0}
         * (Refer to file "arch/tile/include/asm/uaccess.h" for details).
         * For either load or store, byte-wise operation is performed by calling
         * get_user() or put_user(). If the macro returns non-zero value,
         * set the value to rx, otherwise set zero to rx. Finally make pc point
         * to next bundle and return.
         */

        if (EX1_PL(regs->ex1) != USER_PL) {

                unsigned long rx = 0;
                unsigned long x = 0, ret = 0;

                if (y1_br || y1_lr || x1_add ||
                    (load_store_signed !=
                     (load_n_store && load_store_size == 4))) {
                        /* No branch, link, wrong sign-ext or load/store add. */
                        unexpected = true;
                } else if (!unexpected) {
                        if (bundle & TILEGX_BUNDLE_MODE_MASK) {
                                /*
                                 * Fault bundle is Y mode.
                                 * Check if the Y1 and Y0 is the form of
                                 * { movei rx, 0; nop/fnop }, if yes,
                                 * find the rx.
                                 */

                                if ((get_Opcode_Y1(bundle) == ADDI_OPCODE_Y1)
                                    && (get_SrcA_Y1(bundle) == TREG_ZERO) &&
                                    (get_Imm8_Y1(bundle) == 0) &&
                                    is_bundle_y0_nop(bundle)) {
                                        rx = get_Dest_Y1(bundle);
                                } else if ((get_Opcode_Y0(bundle) ==
                                            ADDI_OPCODE_Y0) &&
                                           (get_SrcA_Y0(bundle) == TREG_ZERO) &&
                                           (get_Imm8_Y0(bundle) == 0) &&
                                           is_bundle_y1_nop(bundle)) {
                                        rx = get_Dest_Y0(bundle);
                                } else {
                                        unexpected = true;
                                }
                        } else {
                                /*
                                 * Fault bundle is X mode.
                                 * Check if the X0 is 'movei rx, 0',
                                 * if yes, find the rx.
                                 */

                                if ((get_Opcode_X0(bundle) == IMM8_OPCODE_X0)
                                    && (get_Imm8OpcodeExtension_X0(bundle) ==
                                        ADDI_IMM8_OPCODE_X0) &&
                                    (get_SrcA_X0(bundle) == TREG_ZERO) &&
                                    (get_Imm8_X0(bundle) == 0)) {
                                        rx = get_Dest_X0(bundle);
                                } else {
                                        unexpected = true;
                                }
                        }

                        /* rx should be less than 56. */
                        if (!unexpected && (rx >= 56))
                                unexpected = true;
                }

                if (!search_exception_tables(regs->pc)) {
                        /* No fixup in the exception tables for the pc. */
                        unexpected = true;
                }

                if (unexpected) {
                        /* Unexpected unalign kernel fault. */
                        struct task_struct *tsk = validate_current();

                        bust_spinlocks(1);

                        show_regs(regs);

                        if (unlikely(tsk->pid < 2)) {
                                panic("Kernel unalign fault running %s!",
                                      tsk->pid ? "init" : "the idle task");
                        }
#ifdef SUPPORT_DIE
                        die("Oops", regs);
#endif
                        bust_spinlocks(1);

                        do_group_exit(SIGKILL);

                } else {
                        unsigned long i, b = 0;
                        unsigned char *ptr =
                                (unsigned char *)regs->regs[ra];
                        if (load_n_store) {
                                /* handle get_user(x, ptr) */
                                for (i = 0; i < load_store_size; i++) {
                                        ret = get_user(b, ptr++);
                                        if (!ret) {
                                                /* Success! update x. */
#ifdef __LITTLE_ENDIAN
                                                x |= (b << (8 * i));
#else
                                                x <<= 8;
                                                x |= b;
#endif /* __LITTLE_ENDIAN */
                                        } else {
                                                x = 0;
                                                break;
                                        }
                                }

                                /* Sign-extend 4-byte loads. */
                                if (load_store_size == 4)
                                        x = (long)(int)x;

                                /* Set register rd. */
                                regs->regs[rd] = x;

                                /* Set register rx. */
                                regs->regs[rx] = ret;

                                /* Bump pc. */
                                regs->pc += 8;

                        } else {
                                /* Handle put_user(x, ptr) */
                                x = regs->regs[rb];
#ifdef __LITTLE_ENDIAN
                                b = x;
#else
                                /*
                                 * Swap x in order to store x from low
                                 * to high memory same as the
                                 * little-endian case.
                                 */
                                switch (load_store_size) {
                                case 8:
                                        b = swab64(x);
                                        break;
                                case 4:
                                        b = swab32(x);
                                        break;
                                case 2:
                                        b = swab16(x);
                                        break;
                                }
#endif /* __LITTLE_ENDIAN */
                                for (i = 0; i < load_store_size; i++) {
                                        ret = put_user(b, ptr++);
                                        if (ret)
                                                break;
                                        /* Success! shift 1 byte. */
                                        b >>= 8;
                                }
                                /* Set register rx. */
                                regs->regs[rx] = ret;

                                /* Bump pc. */
                                regs->pc += 8;
                        }
                }

                unaligned_fixup_count++;

                if (unaligned_printk) {
                        pr_info("%s/%d - Unalign fixup for kernel access to userspace %lx\n",
                                current->comm, current->pid, regs->regs[ra]);
                }

                /* Done! Return to the exception handler. */
                return;
        }

        if ((align_ctl == 0) || unexpected) {
                siginfo_t info = {
                        .si_signo = SIGBUS,
                        .si_code = BUS_ADRALN,
                        .si_addr = (unsigned char __user *)0
                };
                if (unaligned_printk)
                        pr_info("Unalign bundle: unexp @%llx, %llx\n",
                                (unsigned long long)regs->pc,
                                (unsigned long long)bundle);

                if (ra < 56) {
                        unsigned long uaa = (unsigned long)regs->regs[ra];
                        /* Set bus Address. */
                        info.si_addr = (unsigned char __user *)uaa;
                }

                unaligned_fixup_count++;

                trace_unhandled_signal("unaligned fixup trap", regs,
                                       (unsigned long)info.si_addr, SIGBUS);

                force_sig_info(info.si_signo, &info, current);
                return;
        }

#ifdef __LITTLE_ENDIAN
#define UA_FIXUP_ADDR_DELTA          1
#define UA_FIXUP_BFEXT_START(_B_)    0
#define UA_FIXUP_BFEXT_END(_B_)     (8 * (_B_) - 1)
#else /* __BIG_ENDIAN */
#define UA_FIXUP_ADDR_DELTA          -1
#define UA_FIXUP_BFEXT_START(_B_)   (64 - 8 * (_B_))
#define UA_FIXUP_BFEXT_END(_B_)      63
#endif /* __LITTLE_ENDIAN */



        if ((ra != rb) && (rd != TREG_SP) && !alias &&
            !y1_br && !y1_lr && !x1_add) {
                /*
                 * Simple case: ra != rb and no register alias found,
                 * and no branch or link. This will be the majority.
                 * We can do a little better for simplae case than the
                 * generic scheme below.
                 */
                if (!load_n_store) {
                        /*
                         * Simple store: ra != rb, no need for scratch register.
                         * Just store and rotate to right bytewise.
                         */
#ifdef __BIG_ENDIAN
                        frag.insn[n++] =
                                jit_x0_addi(ra, ra, load_store_size - 1) |
                                jit_x1_fnop();
#endif /* __BIG_ENDIAN */
                        for (k = 0; k < load_store_size; k++) {
                                /* Store a byte. */
                                frag.insn[n++] =
                                        jit_x0_rotli(rb, rb, 56) |
                                        jit_x1_st1_add(ra, rb,
                                                       UA_FIXUP_ADDR_DELTA);
                        }
#ifdef __BIG_ENDIAN
                        frag.insn[n] = jit_x1_addi(ra, ra, 1);
#else
                        frag.insn[n] = jit_x1_addi(ra, ra,
                                                   -1 * load_store_size);
#endif /* __LITTLE_ENDIAN */

                        if (load_store_size == 8) {
                                frag.insn[n] |= jit_x0_fnop();
                        } else if (load_store_size == 4) {
                                frag.insn[n] |= jit_x0_rotli(rb, rb, 32);
                        } else { /* = 2 */
                                frag.insn[n] |= jit_x0_rotli(rb, rb, 16);
                        }
                        n++;
                        if (bundle_2_enable)
                                frag.insn[n++] = bundle_2;
                        frag.insn[n++] = jit_x0_fnop() | jit_x1_iret();
                } else {
                        if (rd == ra) {
                                /* Use two clobber registers: clob1/2. */
                                frag.insn[n++] =
                                        jit_x0_addi(TREG_SP, TREG_SP, -16) |
                                        jit_x1_fnop();
                                frag.insn[n++] =
                                        jit_x0_addi(clob1, ra, 7) |
                                        jit_x1_st_add(TREG_SP, clob1, -8);
                                frag.insn[n++] =
                                        jit_x0_addi(clob2, ra, 0) |
                                        jit_x1_st(TREG_SP, clob2);
                                frag.insn[n++] =
                                        jit_x0_fnop() |
                                        jit_x1_ldna(rd, ra);
                                frag.insn[n++] =
                                        jit_x0_fnop() |
                                        jit_x1_ldna(clob1, clob1);
                                /*
                                 * Note: we must make sure that rd must not
                                 * be sp. Recover clob1/2 from stack.
                                 */
                                frag.insn[n++] =
                                        jit_x0_dblalign(rd, clob1, clob2) |
                                        jit_x1_ld_add(clob2, TREG_SP, 8);
                                frag.insn[n++] =
                                        jit_x0_fnop() |
                                        jit_x1_ld_add(clob1, TREG_SP, 16);
                        } else {
                                /* Use one clobber register: clob1 only. */
                                frag.insn[n++] =
                                        jit_x0_addi(TREG_SP, TREG_SP, -16) |
                                        jit_x1_fnop();
                                frag.insn[n++] =
                                        jit_x0_addi(clob1, ra, 7) |
                                        jit_x1_st(TREG_SP, clob1);
                                frag.insn[n++] =
                                        jit_x0_fnop() |
                                        jit_x1_ldna(rd, ra);
                                frag.insn[n++] =
                                        jit_x0_fnop() |
                                        jit_x1_ldna(clob1, clob1);
                                /*
                                 * Note: we must make sure that rd must not
                                 * be sp. Recover clob1 from stack.
                                 */
                                frag.insn[n++] =
                                        jit_x0_dblalign(rd, clob1, ra) |
                                        jit_x1_ld_add(clob1, TREG_SP, 16);
                        }

                        if (bundle_2_enable)
                                frag.insn[n++] = bundle_2;
                        /*
                         * For non 8-byte load, extract corresponding bytes and
                         * signed extension.
                         */
                        if (load_store_size == 4) {
                                if (load_store_signed)
                                        frag.insn[n++] =
                                                jit_x0_bfexts(
                                                        rd, rd,
                                                        UA_FIXUP_BFEXT_START(4),
                                                        UA_FIXUP_BFEXT_END(4)) |
                                                jit_x1_fnop();
                                else
                                        frag.insn[n++] =
                                                jit_x0_bfextu(
                                                        rd, rd,
                                                        UA_FIXUP_BFEXT_START(4),
                                                        UA_FIXUP_BFEXT_END(4)) |
                                                jit_x1_fnop();
                        } else if (load_store_size == 2) {
                                if (load_store_signed)
                                        frag.insn[n++] =
                                                jit_x0_bfexts(
                                                        rd, rd,
                                                        UA_FIXUP_BFEXT_START(2),
                                                        UA_FIXUP_BFEXT_END(2)) |
                                                jit_x1_fnop();
                                else
                                        frag.insn[n++] =
                                                jit_x0_bfextu(
                                                        rd, rd,
                                                        UA_FIXUP_BFEXT_START(2),
                                                        UA_FIXUP_BFEXT_END(2)) |
                                                jit_x1_fnop();
                        }

                        frag.insn[n++] =
                                jit_x0_fnop()  |
                                jit_x1_iret();
                }
        } else if (!load_n_store) {

                /*
                 * Generic memory store cases: use 3 clobber registers.
                 *
                 * Alloc space for saveing clob2,1,3 on user's stack.
                 * register clob3 points to where clob2 saved, followed by
                 * clob1 and 3 from high to low memory.
                 */
                frag.insn[n++] =
                        jit_x0_addi(TREG_SP, TREG_SP, -32)    |
                        jit_x1_fnop();
                frag.insn[n++] =
                        jit_x0_addi(clob3, TREG_SP, 16)  |
                        jit_x1_st_add(TREG_SP, clob3, 8);
#ifdef __LITTLE_ENDIAN
                frag.insn[n++] =
                        jit_x0_addi(clob1, ra, 0)   |
                        jit_x1_st_add(TREG_SP, clob1, 8);
#else
                frag.insn[n++] =
                        jit_x0_addi(clob1, ra, load_store_size - 1)   |
                        jit_x1_st_add(TREG_SP, clob1, 8);
#endif
                if (load_store_size == 8) {
                        /*
                         * We save one byte a time, not for fast, but compact
                         * code. After each store, data source register shift
                         * right one byte. unchanged after 8 stores.
                         */
                        frag.insn[n++] =
                                jit_x0_addi(clob2, TREG_ZERO, 7)     |
                                jit_x1_st_add(TREG_SP, clob2, 16);
                        frag.insn[n++] =
                                jit_x0_rotli(rb, rb, 56)      |
                                jit_x1_st1_add(clob1, rb, UA_FIXUP_ADDR_DELTA);
                        frag.insn[n++] =
                                jit_x0_addi(clob2, clob2, -1) |
                                jit_x1_bnezt(clob2, -1);
                        frag.insn[n++] =
                                jit_x0_fnop()                 |
                                jit_x1_addi(clob2, y1_br_reg, 0);
                } else if (load_store_size == 4) {
                        frag.insn[n++] =
                                jit_x0_addi(clob2, TREG_ZERO, 3)     |
                                jit_x1_st_add(TREG_SP, clob2, 16);
                        frag.insn[n++] =
                                jit_x0_rotli(rb, rb, 56)      |
                                jit_x1_st1_add(clob1, rb, UA_FIXUP_ADDR_DELTA);
                        frag.insn[n++] =
                                jit_x0_addi(clob2, clob2, -1) |
                                jit_x1_bnezt(clob2, -1);
                        /*
                         * same as 8-byte case, but need shift another 4
                         * byte to recover rb for 4-byte store.
                         */
                        frag.insn[n++] = jit_x0_rotli(rb, rb, 32)      |
                                jit_x1_addi(clob2, y1_br_reg, 0);
                } else { /* =2 */
                        frag.insn[n++] =
                                jit_x0_addi(clob2, rb, 0)     |
                                jit_x1_st_add(TREG_SP, clob2, 16);
                        for (k = 0; k < 2; k++) {
                                frag.insn[n++] =
                                        jit_x0_shrui(rb, rb, 8)  |
                                        jit_x1_st1_add(clob1, rb,
                                                       UA_FIXUP_ADDR_DELTA);
                        }
                        frag.insn[n++] =
                                jit_x0_addi(rb, clob2, 0)       |
                                jit_x1_addi(clob2, y1_br_reg, 0);
                }

                if (bundle_2_enable)
                        frag.insn[n++] = bundle_2;

                if (y1_lr) {
                        frag.insn[n++] =
                                jit_x0_fnop()                    |
                                jit_x1_mfspr(y1_lr_reg,
                                             SPR_EX_CONTEXT_0_0);
                }
                if (y1_br) {
                        frag.insn[n++] =
                                jit_x0_fnop()                    |
                                jit_x1_mtspr(SPR_EX_CONTEXT_0_0,
                                             clob2);
                }
                if (x1_add) {
                        frag.insn[n++] =
                                jit_x0_addi(ra, ra, x1_add_imm8) |
                                jit_x1_ld_add(clob2, clob3, -8);
                } else {
                        frag.insn[n++] =
                                jit_x0_fnop()                    |
                                jit_x1_ld_add(clob2, clob3, -8);
                }
                frag.insn[n++] =
                        jit_x0_fnop()   |
                        jit_x1_ld_add(clob1, clob3, -8);
                frag.insn[n++] = jit_x0_fnop()   | jit_x1_ld(clob3, clob3);
                frag.insn[n++] = jit_x0_fnop()   | jit_x1_iret();

        } else {
                /*
                 * Generic memory load cases.
                 *
                 * Alloc space for saveing clob1,2,3 on user's stack.
                 * register clob3 points to where clob1 saved, followed
                 * by clob2 and 3 from high to low memory.
                 */

                frag.insn[n++] =
                        jit_x0_addi(TREG_SP, TREG_SP, -32) |
                        jit_x1_fnop();
                frag.insn[n++] =
                        jit_x0_addi(clob3, TREG_SP, 16) |
                        jit_x1_st_add(TREG_SP, clob3, 8);
                frag.insn[n++] =
                        jit_x0_addi(clob2, ra, 0) |
                        jit_x1_st_add(TREG_SP, clob2, 8);

                if (y1_br) {
                        frag.insn[n++] =
                                jit_x0_addi(clob1, y1_br_reg, 0) |
                                jit_x1_st_add(TREG_SP, clob1, 16);
                } else {
                        frag.insn[n++] =
                                jit_x0_fnop() |
                                jit_x1_st_add(TREG_SP, clob1, 16);
                }

                if (bundle_2_enable)
                        frag.insn[n++] = bundle_2;

                if (y1_lr) {
                        frag.insn[n++] =
                                jit_x0_fnop()  |
                                jit_x1_mfspr(y1_lr_reg,
                                             SPR_EX_CONTEXT_0_0);
                }

                if (y1_br) {
                        frag.insn[n++] =
                                jit_x0_fnop() |
                                jit_x1_mtspr(SPR_EX_CONTEXT_0_0,
                                             clob1);
                }

                frag.insn[n++] =
                        jit_x0_addi(clob1, clob2, 7)      |
                        jit_x1_ldna(rd, clob2);
                frag.insn[n++] =
                        jit_x0_fnop()                     |
                        jit_x1_ldna(clob1, clob1);
                frag.insn[n++] =
                        jit_x0_dblalign(rd, clob1, clob2) |
                        jit_x1_ld_add(clob1, clob3, -8);
                if (x1_add) {
                        frag.insn[n++] =
                                jit_x0_addi(ra, ra, x1_add_imm8) |
                                jit_x1_ld_add(clob2, clob3, -8);
                } else {
                        frag.insn[n++] =
                                jit_x0_fnop()  |
                                jit_x1_ld_add(clob2, clob3, -8);
                }

                frag.insn[n++] =
                        jit_x0_fnop() |
                        jit_x1_ld(clob3, clob3);

                if (load_store_size == 4) {
                        if (load_store_signed)
                                frag.insn[n++] =
                                        jit_x0_bfexts(
                                                rd, rd,
                                                UA_FIXUP_BFEXT_START(4),
                                                UA_FIXUP_BFEXT_END(4)) |
                                        jit_x1_fnop();
                        else
                                frag.insn[n++] =
                                        jit_x0_bfextu(
                                                rd, rd,
                                                UA_FIXUP_BFEXT_START(4),
                                                UA_FIXUP_BFEXT_END(4)) |
                                        jit_x1_fnop();
                } else if (load_store_size == 2) {
                        if (load_store_signed)
                                frag.insn[n++] =
                                        jit_x0_bfexts(
                                                rd, rd,
                                                UA_FIXUP_BFEXT_START(2),
                                                UA_FIXUP_BFEXT_END(2)) |
                                        jit_x1_fnop();
                        else
                                frag.insn[n++] =
                                        jit_x0_bfextu(
                                                rd, rd,
                                                UA_FIXUP_BFEXT_START(2),
                                                UA_FIXUP_BFEXT_END(2)) |
                                        jit_x1_fnop();
                }

                frag.insn[n++] = jit_x0_fnop() | jit_x1_iret();
        }

        /* Max JIT bundle count is 14. */
        WARN_ON(n > 14);

        if (!unexpected) {
                int status = 0;
                int idx = (regs->pc >> 3) &
                        ((1ULL << (PAGE_SHIFT - UNALIGN_JIT_SHIFT)) - 1);

                frag.pc = regs->pc;
                frag.bundle = bundle;

                if (unaligned_printk) {
                        pr_info("%s/%d, Unalign fixup: pc=%lx bundle=%lx %d %d %d %d %d %d %d %d\n",
                                current->comm, current->pid,
                                (unsigned long)frag.pc,
                                (unsigned long)frag.bundle,
                                (int)alias, (int)rd, (int)ra,
                                (int)rb, (int)bundle_2_enable,
                                (int)y1_lr, (int)y1_br, (int)x1_add);

                        for (k = 0; k < n; k += 2)
                                pr_info("[%d] %016llx %016llx\n",
                                        k, (unsigned long long)frag.insn[k],
                                        (unsigned long long)frag.insn[k+1]);
                }

                /* Swap bundle byte order for big endian sys. */
#ifdef __BIG_ENDIAN
                frag.bundle = GX_INSN_BSWAP(frag.bundle);
                for (k = 0; k < n; k++)
                        frag.insn[k] = GX_INSN_BSWAP(frag.insn[k]);
#endif /* __BIG_ENDIAN */

                status = copy_to_user((void __user *)&jit_code_area[idx],
                                      &frag, sizeof(frag));
                if (status) {
                        /* Fail to copy JIT into user land. send SIGSEGV. */
                        siginfo_t info = {
                                .si_signo = SIGSEGV,
                                .si_code = SEGV_MAPERR,
                                .si_addr = (void __user *)&jit_code_area[idx]
                        };

                        pr_warn("Unalign fixup: pid=%d %s jit_code_area=%llx\n",
                                current->pid, current->comm,
                                (unsigned long long)&jit_code_area[idx]);

                        trace_unhandled_signal("segfault in unalign fixup",
                                               regs,
                                               (unsigned long)info.si_addr,
                                               SIGSEGV);
                        force_sig_info(info.si_signo, &info, current);
                        return;
                }


                /* Do a cheaper increment, not accurate. */
                unaligned_fixup_count++;
                __flush_icache_range((unsigned long)&jit_code_area[idx],
                                     (unsigned long)&jit_code_area[idx] +
                                     sizeof(frag));

                /* Setup SPR_EX_CONTEXT_0_0/1 for returning to user program.*/
                __insn_mtspr(SPR_EX_CONTEXT_0_0, regs->pc + 8);
                __insn_mtspr(SPR_EX_CONTEXT_0_1, PL_ICS_EX1(USER_PL, 0));

                /* Modify pc at the start of new JIT. */
                regs->pc = (unsigned long)&jit_code_area[idx].insn[0];
                /* Set ICS in SPR_EX_CONTEXT_K_1. */
                regs->ex1 = PL_ICS_EX1(USER_PL, 1);
        }
}


/*
 * C function to generate unalign data JIT. Called from unalign data
 * interrupt handler.
 *
 * First check if unalign fix is disabled or exception did not not come from
 * user space or sp register points to unalign address, if true, generate a
 * SIGBUS. Then map a page into user space as JIT area if it is not mapped
 * yet. Genenerate JIT code by calling jit_bundle_gen(). After that return
 * back to exception handler.
 *
 * The exception handler will "iret" to new generated JIT code after
 * restoring caller saved registers. In theory, the JIT code will perform
 * another "iret" to resume user's program.
 */

void do_unaligned(struct pt_regs *regs, int vecnum)
{
        tilegx_bundle_bits __user  *pc;
        tilegx_bundle_bits bundle;
        struct thread_info *info = current_thread_info();
        int align_ctl;

        /* Checks the per-process unaligned JIT flags */
        align_ctl = unaligned_fixup;
        switch (task_thread_info(current)->align_ctl) {
        case PR_UNALIGN_NOPRINT:
                align_ctl = 1;
                break;
        case PR_UNALIGN_SIGBUS:
                align_ctl = 0;
                break;
        }

        /* Enable iterrupt in order to access user land. */
        local_irq_enable();

        /*
         * The fault came from kernel space. Two choices:
         * (a) unaligned_fixup < 1, we will first call get/put_user fixup
         *     to return -EFAULT. If no fixup, simply panic the kernel.
         * (b) unaligned_fixup >=1, we will try to fix the unaligned access
         *     if it was triggered by get_user/put_user() macros. Panic the
         *     kernel if it is not fixable.
         */

        if (EX1_PL(regs->ex1) != USER_PL) {

                if (align_ctl < 1) {
                        unaligned_fixup_count++;
                        /* If exception came from kernel, try fix it up. */
                        if (fixup_exception(regs)) {
                                if (unaligned_printk)
                                        pr_info("Unalign fixup: %d %llx @%llx\n",
                                                (int)unaligned_fixup,
                                                (unsigned long long)regs->ex1,
                                                (unsigned long long)regs->pc);
                        } else {
                                /* Not fixable. Go panic. */
                                panic("Unalign exception in Kernel. pc=%lx",
                                      regs->pc);
                        }
                } else {
                        /*
                         * Try to fix the exception. If we can't, panic the
                         * kernel.
                         */
                        bundle = GX_INSN_BSWAP(
                                *((tilegx_bundle_bits *)(regs->pc)));
                        jit_bundle_gen(regs, bundle, align_ctl);
                }
                return;
        }

        /*
         * Fault came from user with ICS or stack is not aligned.
         * If so, we will trigger SIGBUS.
         */
        if ((regs->sp & 0x7) || (regs->ex1) || (align_ctl < 0)) {
                siginfo_t info = {
                        .si_signo = SIGBUS,
                        .si_code = BUS_ADRALN,
                        .si_addr = (unsigned char __user *)0
                };

                if (unaligned_printk)
                        pr_info("Unalign fixup: %d %llx @%llx\n",
                                (int)unaligned_fixup,
                                (unsigned long long)regs->ex1,
                                (unsigned long long)regs->pc);

                unaligned_fixup_count++;

                trace_unhandled_signal("unaligned fixup trap", regs, 0, SIGBUS);
                force_sig_info(info.si_signo, &info, current);
                return;
        }


        /* Read the bundle caused the exception! */
        pc = (tilegx_bundle_bits __user *)(regs->pc);
        if (get_user(bundle, pc) != 0) {
                /* Probably never be here since pc is valid user address.*/
                siginfo_t info = {
                        .si_signo = SIGSEGV,
                        .si_code = SEGV_MAPERR,
                        .si_addr = (void __user *)pc
                };
                pr_err("Couldn't read instruction at %p trying to step\n", pc);
                trace_unhandled_signal("segfault in unalign fixup", regs,
                                       (unsigned long)info.si_addr, SIGSEGV);
                force_sig_info(info.si_signo, &info, current);
                return;
        }

        if (!info->unalign_jit_base) {
                void __user *user_page;

                /*
                 * Allocate a page in userland.
                 * For 64-bit processes we try to place the mapping far
                 * from anything else that might be going on (specifically
                 * 64 GB below the top of the user address space).  If it
                 * happens not to be possible to put it there, it's OK;
                 * the kernel will choose another location and we'll
                 * remember it for later.
                 */
                if (is_compat_task())
                        user_page = NULL;
                else
                        user_page = (void __user *)(TASK_SIZE - (1UL << 36)) +
                                (current->pid << PAGE_SHIFT);

                user_page = (void __user *) vm_mmap(NULL,
                                                    (unsigned long)user_page,
                                                    PAGE_SIZE,
                                                    PROT_EXEC | PROT_READ |
                                                    PROT_WRITE,
#ifdef CONFIG_HOMECACHE
                                                    MAP_CACHE_HOME_TASK |
#endif
                                                    MAP_PRIVATE |
                                                    MAP_ANONYMOUS,
                                                    0);

                if (IS_ERR((void __force *)user_page)) {
                        pr_err("Out of kernel pages trying do_mmap\n");
                        return;
                }

                /* Save the address in the thread_info struct */
                info->unalign_jit_base = user_page;
                if (unaligned_printk)
                        pr_info("Unalign bundle: %d:%d, allocate page @%llx\n",
                                raw_smp_processor_id(), current->pid,
                                (unsigned long long)user_page);
        }

        /* Generate unalign JIT */
        jit_bundle_gen(regs, GX_INSN_BSWAP(bundle), align_ctl);
}

#endif /* __tilegx__ */