// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2013 Huawei Ltd.
 * Author: Jiang Liu <liuj97@gmail.com>
 *
 * Copyright (C) 2014-2016 Zi Shen Lim <zlim.lnx@gmail.com>
 */
#include <linux/bitops.h>
#include <linux/bug.h>
#include <linux/printk.h>
#include <linux/sizes.h>
#include <linux/types.h>

#include <asm/debug-monitors.h>
#include <asm/errno.h>
#include <asm/insn.h>
#include <asm/kprobes.h>

#define AARCH64_INSN_SF_BIT     BIT(31)
#define AARCH64_INSN_N_BIT      BIT(22)
#define AARCH64_INSN_LSL_12     BIT(22)

static const int aarch64_insn_encoding_class[] = {
        AARCH64_INSN_CLS_UNKNOWN,
        AARCH64_INSN_CLS_UNKNOWN,
        AARCH64_INSN_CLS_SVE,
        AARCH64_INSN_CLS_UNKNOWN,
        AARCH64_INSN_CLS_LDST,
        AARCH64_INSN_CLS_DP_REG,
        AARCH64_INSN_CLS_LDST,
        AARCH64_INSN_CLS_DP_FPSIMD,
        AARCH64_INSN_CLS_DP_IMM,
        AARCH64_INSN_CLS_DP_IMM,
        AARCH64_INSN_CLS_BR_SYS,
        AARCH64_INSN_CLS_BR_SYS,
        AARCH64_INSN_CLS_LDST,
        AARCH64_INSN_CLS_DP_REG,
        AARCH64_INSN_CLS_LDST,
        AARCH64_INSN_CLS_DP_FPSIMD,
};

enum aarch64_insn_encoding_class __kprobes aarch64_get_insn_class(u32 insn)
{
        return aarch64_insn_encoding_class[(insn >> 25) & 0xf];
}

bool __kprobes aarch64_insn_is_steppable_hint(u32 insn)
{
        if (!aarch64_insn_is_hint(insn))
                return false;

        switch (insn & 0xFE0) {
        case AARCH64_INSN_HINT_XPACLRI:
        case AARCH64_INSN_HINT_PACIA_1716:
        case AARCH64_INSN_HINT_PACIB_1716:
        case AARCH64_INSN_HINT_PACIAZ:
        case AARCH64_INSN_HINT_PACIASP:
        case AARCH64_INSN_HINT_PACIBZ:
        case AARCH64_INSN_HINT_PACIBSP:
        case AARCH64_INSN_HINT_BTI:
        case AARCH64_INSN_HINT_BTIC:
        case AARCH64_INSN_HINT_BTIJ:
        case AARCH64_INSN_HINT_BTIJC:
        case AARCH64_INSN_HINT_NOP:
                return true;
        default:
                return false;
        }
}

bool aarch64_insn_is_branch_imm(u32 insn)
{
        return (aarch64_insn_is_b(insn) || aarch64_insn_is_bl(insn) ||
                aarch64_insn_is_tbz(insn) || aarch64_insn_is_tbnz(insn) ||
                aarch64_insn_is_cbz(insn) || aarch64_insn_is_cbnz(insn) ||
                aarch64_insn_is_bcond(insn));
}

bool __kprobes aarch64_insn_uses_literal(u32 insn)
{
        /* ldr/ldrsw (literal), prfm */

        return aarch64_insn_is_ldr_lit(insn) ||
                aarch64_insn_is_ldrsw_lit(insn) ||
                aarch64_insn_is_adr_adrp(insn) ||
                aarch64_insn_is_prfm_lit(insn);
}

bool __kprobes aarch64_insn_is_branch(u32 insn)
{
        /* b, bl, cb*, tb*, ret*, b.cond, br*, blr* */

        return aarch64_insn_is_b(insn) ||
                aarch64_insn_is_bl(insn) ||
                aarch64_insn_is_cbz(insn) ||
                aarch64_insn_is_cbnz(insn) ||
                aarch64_insn_is_tbz(insn) ||
                aarch64_insn_is_tbnz(insn) ||
                aarch64_insn_is_ret(insn) ||
                aarch64_insn_is_ret_auth(insn) ||
                aarch64_insn_is_br(insn) ||
                aarch64_insn_is_br_auth(insn) ||
                aarch64_insn_is_blr(insn) ||
                aarch64_insn_is_blr_auth(insn) ||
                aarch64_insn_is_bcond(insn);
}

static int __kprobes aarch64_get_imm_shift_mask(enum aarch64_insn_imm_type type,
                                                u32 *maskp, int *shiftp)
{
        u32 mask;
        int shift;

        switch (type) {
        case AARCH64_INSN_IMM_26:
                mask = BIT(26) - 1;
                shift = 0;
                break;
        case AARCH64_INSN_IMM_19:
                mask = BIT(19) - 1;
                shift = 5;
                break;
        case AARCH64_INSN_IMM_16:
                mask = BIT(16) - 1;
                shift = 5;
                break;
        case AARCH64_INSN_IMM_14:
                mask = BIT(14) - 1;
                shift = 5;
                break;
        case AARCH64_INSN_IMM_12:
                mask = BIT(12) - 1;
                shift = 10;
                break;
        case AARCH64_INSN_IMM_9:
                mask = BIT(9) - 1;
                shift = 12;
                break;
        case AARCH64_INSN_IMM_7:
                mask = BIT(7) - 1;
                shift = 15;
                break;
        case AARCH64_INSN_IMM_6:
        case AARCH64_INSN_IMM_S:
                mask = BIT(6) - 1;
                shift = 10;
                break;
        case AARCH64_INSN_IMM_R:
                mask = BIT(6) - 1;
                shift = 16;
                break;
        case AARCH64_INSN_IMM_N:
                mask = 1;
                shift = 22;
                break;
        default:
                return -EINVAL;
        }

        *maskp = mask;
        *shiftp = shift;

        return 0;
}

#define ADR_IMM_HILOSPLIT       2
#define ADR_IMM_SIZE            SZ_2M
#define ADR_IMM_LOMASK          ((1 << ADR_IMM_HILOSPLIT) - 1)
#define ADR_IMM_HIMASK          ((ADR_IMM_SIZE >> ADR_IMM_HILOSPLIT) - 1)
#define ADR_IMM_LOSHIFT         29
#define ADR_IMM_HISHIFT         5

u64 aarch64_insn_decode_immediate(enum aarch64_insn_imm_type type, u32 insn)
{
        u32 immlo, immhi, mask;
        int shift;

        switch (type) {
        case AARCH64_INSN_IMM_ADR:
                shift = 0;
                immlo = (insn >> ADR_IMM_LOSHIFT) & ADR_IMM_LOMASK;
                immhi = (insn >> ADR_IMM_HISHIFT) & ADR_IMM_HIMASK;
                insn = (immhi << ADR_IMM_HILOSPLIT) | immlo;
                mask = ADR_IMM_SIZE - 1;
                break;
        default:
                if (aarch64_get_imm_shift_mask(type, &mask, &shift) < 0) {
                        pr_err("%s: unknown immediate encoding %d\n", __func__,
                               type);
                        return 0;
                }
        }

        return (insn >> shift) & mask;
}

u32 __kprobes aarch64_insn_encode_immediate(enum aarch64_insn_imm_type type,
                                  u32 insn, u64 imm)
{
        u32 immlo, immhi, mask;
        int shift;

        if (insn == AARCH64_BREAK_FAULT)
                return AARCH64_BREAK_FAULT;

        switch (type) {
        case AARCH64_INSN_IMM_ADR:
                shift = 0;
                immlo = (imm & ADR_IMM_LOMASK) << ADR_IMM_LOSHIFT;
                imm >>= ADR_IMM_HILOSPLIT;
                immhi = (imm & ADR_IMM_HIMASK) << ADR_IMM_HISHIFT;
                imm = immlo | immhi;
                mask = ((ADR_IMM_LOMASK << ADR_IMM_LOSHIFT) |
                        (ADR_IMM_HIMASK << ADR_IMM_HISHIFT));
                break;
        default:
                if (aarch64_get_imm_shift_mask(type, &mask, &shift) < 0) {
                        pr_err("%s: unknown immediate encoding %d\n", __func__,
                               type);
                        return AARCH64_BREAK_FAULT;
                }
        }

        /* Update the immediate field. */
        insn &= ~(mask << shift);
        insn |= (imm & mask) << shift;

        return insn;
}

u32 aarch64_insn_decode_register(enum aarch64_insn_register_type type,
                                        u32 insn)
{
        int shift;

        switch (type) {
        case AARCH64_INSN_REGTYPE_RT:
        case AARCH64_INSN_REGTYPE_RD:
                shift = 0;
                break;
        case AARCH64_INSN_REGTYPE_RN:
                shift = 5;
                break;
        case AARCH64_INSN_REGTYPE_RT2:
        case AARCH64_INSN_REGTYPE_RA:
                shift = 10;
                break;
        case AARCH64_INSN_REGTYPE_RM:
                shift = 16;
                break;
        default:
                pr_err("%s: unknown register type encoding %d\n", __func__,
                       type);
                return 0;
        }

        return (insn >> shift) & GENMASK(4, 0);
}

static u32 aarch64_insn_encode_register(enum aarch64_insn_register_type type,
                                        u32 insn,
                                        enum aarch64_insn_register reg)
{
        int shift;

        if (insn == AARCH64_BREAK_FAULT)
                return AARCH64_BREAK_FAULT;

        if (reg < AARCH64_INSN_REG_0 || reg > AARCH64_INSN_REG_SP) {
                pr_err("%s: unknown register encoding %d\n", __func__, reg);
                return AARCH64_BREAK_FAULT;
        }

        switch (type) {
        case AARCH64_INSN_REGTYPE_RT:
        case AARCH64_INSN_REGTYPE_RD:
                shift = 0;
                break;
        case AARCH64_INSN_REGTYPE_RN:
                shift = 5;
                break;
        case AARCH64_INSN_REGTYPE_RT2:
        case AARCH64_INSN_REGTYPE_RA:
                shift = 10;
                break;
        case AARCH64_INSN_REGTYPE_RM:
        case AARCH64_INSN_REGTYPE_RS:
                shift = 16;
                break;
        default:
                pr_err("%s: unknown register type encoding %d\n", __func__,
                       type);
                return AARCH64_BREAK_FAULT;
        }

        insn &= ~(GENMASK(4, 0) << shift);
        insn |= reg << shift;

        return insn;
}

static const u32 aarch64_insn_ldst_size[] = {
        [AARCH64_INSN_SIZE_8] = 0,
        [AARCH64_INSN_SIZE_16] = 1,
        [AARCH64_INSN_SIZE_32] = 2,
        [AARCH64_INSN_SIZE_64] = 3,
};

static u32 aarch64_insn_encode_ldst_size(enum aarch64_insn_size_type type,
                                         u32 insn)
{
        u32 size;

        if (type < AARCH64_INSN_SIZE_8 || type > AARCH64_INSN_SIZE_64) {
                pr_err("%s: unknown size encoding %d\n", __func__, type);
                return AARCH64_BREAK_FAULT;
        }

        size = aarch64_insn_ldst_size[type];
        insn &= ~GENMASK(31, 30);
        insn |= size << 30;

        return insn;
}

static inline long branch_imm_common(unsigned long pc, unsigned long addr,
                                     long range)
{
        long offset;

        if ((pc & 0x3) || (addr & 0x3)) {
                pr_err("%s: A64 instructions must be word aligned\n", __func__);
                return range;
        }

        offset = ((long)addr - (long)pc);

        if (offset < -range || offset >= range) {
                pr_err("%s: offset out of range\n", __func__);
                return range;
        }

        return offset;
}

u32 __kprobes aarch64_insn_gen_branch_imm(unsigned long pc, unsigned long addr,
                                          enum aarch64_insn_branch_type type)
{
        u32 insn;
        long offset;

        /*
         * B/BL support [-128M, 128M) offset
         * ARM64 virtual address arrangement guarantees all kernel and module
         * texts are within +/-128M.
         */
        offset = branch_imm_common(pc, addr, SZ_128M);
        if (offset >= SZ_128M)
                return AARCH64_BREAK_FAULT;

        switch (type) {
        case AARCH64_INSN_BRANCH_LINK:
                insn = aarch64_insn_get_bl_value();
                break;
        case AARCH64_INSN_BRANCH_NOLINK:
                insn = aarch64_insn_get_b_value();
                break;
        default:
                pr_err("%s: unknown branch encoding %d\n", __func__, type);
                return AARCH64_BREAK_FAULT;
        }

        return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_26, insn,
                                             offset >> 2);
}

u32 aarch64_insn_gen_comp_branch_imm(unsigned long pc, unsigned long addr,
                                     enum aarch64_insn_register reg,
                                     enum aarch64_insn_variant variant,
                                     enum aarch64_insn_branch_type type)
{
        u32 insn;
        long offset;

        offset = branch_imm_common(pc, addr, SZ_1M);
        if (offset >= SZ_1M)
                return AARCH64_BREAK_FAULT;

        switch (type) {
        case AARCH64_INSN_BRANCH_COMP_ZERO:
                insn = aarch64_insn_get_cbz_value();
                break;
        case AARCH64_INSN_BRANCH_COMP_NONZERO:
                insn = aarch64_insn_get_cbnz_value();
                break;
        default:
                pr_err("%s: unknown branch encoding %d\n", __func__, type);
                return AARCH64_BREAK_FAULT;
        }

        switch (variant) {
        case AARCH64_INSN_VARIANT_32BIT:
                break;
        case AARCH64_INSN_VARIANT_64BIT:
                insn |= AARCH64_INSN_SF_BIT;
                break;
        default:
                pr_err("%s: unknown variant encoding %d\n", __func__, variant);
                return AARCH64_BREAK_FAULT;
        }

        insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RT, insn, reg);

        return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_19, insn,
                                             offset >> 2);
}

u32 aarch64_insn_gen_cond_branch_imm(unsigned long pc, unsigned long addr,
                                     enum aarch64_insn_condition cond)
{
        u32 insn;
        long offset;

        offset = branch_imm_common(pc, addr, SZ_1M);

        insn = aarch64_insn_get_bcond_value();

        if (cond < AARCH64_INSN_COND_EQ || cond > AARCH64_INSN_COND_AL) {
                pr_err("%s: unknown condition encoding %d\n", __func__, cond);
                return AARCH64_BREAK_FAULT;
        }
        insn |= cond;

        return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_19, insn,
                                             offset >> 2);
}

u32 __kprobes aarch64_insn_gen_hint(enum aarch64_insn_hint_cr_op op)
{
        return aarch64_insn_get_hint_value() | op;
}

u32 __kprobes aarch64_insn_gen_nop(void)
{
        return aarch64_insn_gen_hint(AARCH64_INSN_HINT_NOP);
}

u32 aarch64_insn_gen_branch_reg(enum aarch64_insn_register reg,
                                enum aarch64_insn_branch_type type)
{
        u32 insn;

        switch (type) {
        case AARCH64_INSN_BRANCH_NOLINK:
                insn = aarch64_insn_get_br_value();
                break;
        case AARCH64_INSN_BRANCH_LINK:
                insn = aarch64_insn_get_blr_value();
                break;
        case AARCH64_INSN_BRANCH_RETURN:
                insn = aarch64_insn_get_ret_value();
                break;
        default:
                pr_err("%s: unknown branch encoding %d\n", __func__, type);
                return AARCH64_BREAK_FAULT;
        }

        return aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RN, insn, reg);
}

u32 aarch64_insn_gen_load_store_reg(enum aarch64_insn_register reg,
                                    enum aarch64_insn_register base,
                                    enum aarch64_insn_register offset,
                                    enum aarch64_insn_size_type size,
                                    enum aarch64_insn_ldst_type type)
{
        u32 insn;

        switch (type) {
        case AARCH64_INSN_LDST_LOAD_REG_OFFSET:
                insn = aarch64_insn_get_ldr_reg_value();
                break;
        case AARCH64_INSN_LDST_STORE_REG_OFFSET:
                insn = aarch64_insn_get_str_reg_value();
                break;
        default:
                pr_err("%s: unknown load/store encoding %d\n", __func__, type);
                return AARCH64_BREAK_FAULT;
        }

        insn = aarch64_insn_encode_ldst_size(size, insn);

        insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RT, insn, reg);

        insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RN, insn,
                                            base);

        return aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RM, insn,
                                            offset);
}

u32 aarch64_insn_gen_load_store_imm(enum aarch64_insn_register reg,
                                    enum aarch64_insn_register base,
                                    unsigned int imm,
                                    enum aarch64_insn_size_type size,
                                    enum aarch64_insn_ldst_type type)
{
        u32 insn;
        u32 shift;

        if (size < AARCH64_INSN_SIZE_8 || size > AARCH64_INSN_SIZE_64) {
                pr_err("%s: unknown size encoding %d\n", __func__, type);
                return AARCH64_BREAK_FAULT;
        }

        shift = aarch64_insn_ldst_size[size];
        if (imm & ~(BIT(12 + shift) - BIT(shift))) {
                pr_err("%s: invalid imm: %d\n", __func__, imm);
                return AARCH64_BREAK_FAULT;
        }

        imm >>= shift;

        switch (type) {
        case AARCH64_INSN_LDST_LOAD_IMM_OFFSET:
                insn = aarch64_insn_get_ldr_imm_value();
                break;
        case AARCH64_INSN_LDST_STORE_IMM_OFFSET:
                insn = aarch64_insn_get_str_imm_value();
                break;
        default:
                pr_err("%s: unknown load/store encoding %d\n", __func__, type);
                return AARCH64_BREAK_FAULT;
        }

        insn = aarch64_insn_encode_ldst_size(size, insn);

        insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RT, insn, reg);

        insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RN, insn,
                                            base);

        return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_12, insn, imm);
}

u32 aarch64_insn_gen_load_store_pair(enum aarch64_insn_register reg1,
                                     enum aarch64_insn_register reg2,
                                     enum aarch64_insn_register base,
                                     int offset,
                                     enum aarch64_insn_variant variant,
                                     enum aarch64_insn_ldst_type type)
{
        u32 insn;
        int shift;

        switch (type) {
        case AARCH64_INSN_LDST_LOAD_PAIR_PRE_INDEX:
                insn = aarch64_insn_get_ldp_pre_value();
                break;
        case AARCH64_INSN_LDST_STORE_PAIR_PRE_INDEX:
                insn = aarch64_insn_get_stp_pre_value();
                break;
        case AARCH64_INSN_LDST_LOAD_PAIR_POST_INDEX:
                insn = aarch64_insn_get_ldp_post_value();
                break;
        case AARCH64_INSN_LDST_STORE_PAIR_POST_INDEX:
                insn = aarch64_insn_get_stp_post_value();
                break;
        default:
                pr_err("%s: unknown load/store encoding %d\n", __func__, type);
                return AARCH64_BREAK_FAULT;
        }

        switch (variant) {
        case AARCH64_INSN_VARIANT_32BIT:
                if ((offset & 0x3) || (offset < -256) || (offset > 252)) {
                        pr_err("%s: offset must be multiples of 4 in the range of [-256, 252] %d\n",
                               __func__, offset);
                        return AARCH64_BREAK_FAULT;
                }
                shift = 2;
                break;
        case AARCH64_INSN_VARIANT_64BIT:
                if ((offset & 0x7) || (offset < -512) || (offset > 504)) {
                        pr_err("%s: offset must be multiples of 8 in the range of [-512, 504] %d\n",
                               __func__, offset);
                        return AARCH64_BREAK_FAULT;
                }
                shift = 3;
                insn |= AARCH64_INSN_SF_BIT;
                break;
        default:
                pr_err("%s: unknown variant encoding %d\n", __func__, variant);
                return AARCH64_BREAK_FAULT;
        }

        insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RT, insn,
                                            reg1);

        insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RT2, insn,
                                            reg2);

        insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RN, insn,
                                            base);

        return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_7, insn,
                                             offset >> shift);
}

u32 aarch64_insn_gen_load_store_ex(enum aarch64_insn_register reg,
                                   enum aarch64_insn_register base,
                                   enum aarch64_insn_register state,
                                   enum aarch64_insn_size_type size,
                                   enum aarch64_insn_ldst_type type)
{
        u32 insn;

        switch (type) {
        case AARCH64_INSN_LDST_LOAD_EX:
        case AARCH64_INSN_LDST_LOAD_ACQ_EX:
                insn = aarch64_insn_get_load_ex_value();
                if (type == AARCH64_INSN_LDST_LOAD_ACQ_EX)
                        insn |= BIT(15);
                break;
        case AARCH64_INSN_LDST_STORE_EX:
        case AARCH64_INSN_LDST_STORE_REL_EX:
                insn = aarch64_insn_get_store_ex_value();
                if (type == AARCH64_INSN_LDST_STORE_REL_EX)
                        insn |= BIT(15);
                break;
        default:
                pr_err("%s: unknown load/store exclusive encoding %d\n", __func__, type);
                return AARCH64_BREAK_FAULT;
        }

        insn = aarch64_insn_encode_ldst_size(size, insn);

        insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RT, insn,
                                            reg);

        insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RN, insn,
                                            base);

        insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RT2, insn,
                                            AARCH64_INSN_REG_ZR);

        return aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RS, insn,
                                            state);
}

#ifdef CONFIG_ARM64_LSE_ATOMICS
static u32 aarch64_insn_encode_ldst_order(enum aarch64_insn_mem_order_type type,
                                          u32 insn)
{
        u32 order;

        switch (type) {
        case AARCH64_INSN_MEM_ORDER_NONE:
                order = 0;
                break;
        case AARCH64_INSN_MEM_ORDER_ACQ:
                order = 2;
                break;
        case AARCH64_INSN_MEM_ORDER_REL:
                order = 1;
                break;
        case AARCH64_INSN_MEM_ORDER_ACQREL:
                order = 3;
                break;
        default:
                pr_err("%s: unknown mem order %d\n", __func__, type);
                return AARCH64_BREAK_FAULT;
        }

        insn &= ~GENMASK(23, 22);
        insn |= order << 22;

        return insn;
}

u32 aarch64_insn_gen_atomic_ld_op(enum aarch64_insn_register result,
                                  enum aarch64_insn_register address,
                                  enum aarch64_insn_register value,
                                  enum aarch64_insn_size_type size,
                                  enum aarch64_insn_mem_atomic_op op,
                                  enum aarch64_insn_mem_order_type order)
{
        u32 insn;

        switch (op) {
        case AARCH64_INSN_MEM_ATOMIC_ADD:
                insn = aarch64_insn_get_ldadd_value();
                break;
        case AARCH64_INSN_MEM_ATOMIC_CLR:
                insn = aarch64_insn_get_ldclr_value();
                break;
        case AARCH64_INSN_MEM_ATOMIC_EOR:
                insn = aarch64_insn_get_ldeor_value();
                break;
        case AARCH64_INSN_MEM_ATOMIC_SET:
                insn = aarch64_insn_get_ldset_value();
                break;
        case AARCH64_INSN_MEM_ATOMIC_SWP:
                insn = aarch64_insn_get_swp_value();
                break;
        default:
                pr_err("%s: unimplemented mem atomic op %d\n", __func__, op);
                return AARCH64_BREAK_FAULT;
        }

        switch (size) {
        case AARCH64_INSN_SIZE_32:
        case AARCH64_INSN_SIZE_64:
                break;
        default:
                pr_err("%s: unimplemented size encoding %d\n", __func__, size);
                return AARCH64_BREAK_FAULT;
        }

        insn = aarch64_insn_encode_ldst_size(size, insn);

        insn = aarch64_insn_encode_ldst_order(order, insn);

        insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RT, insn,
                                            result);

        insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RN, insn,
                                            address);

        return aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RS, insn,
                                            value);
}

static u32 aarch64_insn_encode_cas_order(enum aarch64_insn_mem_order_type type,
                                         u32 insn)
{
        u32 order;

        switch (type) {
        case AARCH64_INSN_MEM_ORDER_NONE:
                order = 0;
                break;
        case AARCH64_INSN_MEM_ORDER_ACQ:
                order = BIT(22);
                break;
        case AARCH64_INSN_MEM_ORDER_REL:
                order = BIT(15);
                break;
        case AARCH64_INSN_MEM_ORDER_ACQREL:
                order = BIT(15) | BIT(22);
                break;
        default:
                pr_err("%s: unknown mem order %d\n", __func__, type);
                return AARCH64_BREAK_FAULT;
        }

        insn &= ~(BIT(15) | BIT(22));
        insn |= order;

        return insn;
}

u32 aarch64_insn_gen_cas(enum aarch64_insn_register result,
                         enum aarch64_insn_register address,
                         enum aarch64_insn_register value,
                         enum aarch64_insn_size_type size,
                         enum aarch64_insn_mem_order_type order)
{
        u32 insn;

        switch (size) {
        case AARCH64_INSN_SIZE_32:
        case AARCH64_INSN_SIZE_64:
                break;
        default:
                pr_err("%s: unimplemented size encoding %d\n", __func__, size);
                return AARCH64_BREAK_FAULT;
        }

        insn = aarch64_insn_get_cas_value();

        insn = aarch64_insn_encode_ldst_size(size, insn);

        insn = aarch64_insn_encode_cas_order(order, insn);

        insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RT, insn,
                                            result);

        insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RN, insn,
                                            address);

        return aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RS, insn,
                                            value);
}
#endif

static u32 aarch64_insn_encode_prfm_imm(enum aarch64_insn_prfm_type type,
                                        enum aarch64_insn_prfm_target target,
                                        enum aarch64_insn_prfm_policy policy,
                                        u32 insn)
{
        u32 imm_type = 0, imm_target = 0, imm_policy = 0;

        switch (type) {
        case AARCH64_INSN_PRFM_TYPE_PLD:
                break;
        case AARCH64_INSN_PRFM_TYPE_PLI:
                imm_type = BIT(0);
                break;
        case AARCH64_INSN_PRFM_TYPE_PST:
                imm_type = BIT(1);
                break;
        default:
                pr_err("%s: unknown prfm type encoding %d\n", __func__, type);
                return AARCH64_BREAK_FAULT;
        }

        switch (target) {
        case AARCH64_INSN_PRFM_TARGET_L1:
                break;
        case AARCH64_INSN_PRFM_TARGET_L2:
                imm_target = BIT(0);
                break;
        case AARCH64_INSN_PRFM_TARGET_L3:
                imm_target = BIT(1);
                break;
        default:
                pr_err("%s: unknown prfm target encoding %d\n", __func__, target);
                return AARCH64_BREAK_FAULT;
        }

        switch (policy) {
        case AARCH64_INSN_PRFM_POLICY_KEEP:
                break;
        case AARCH64_INSN_PRFM_POLICY_STRM:
                imm_policy = BIT(0);
                break;
        default:
                pr_err("%s: unknown prfm policy encoding %d\n", __func__, policy);
                return AARCH64_BREAK_FAULT;
        }

        /* In this case, imm5 is encoded into Rt field. */
        insn &= ~GENMASK(4, 0);
        insn |= imm_policy | (imm_target << 1) | (imm_type << 3);

        return insn;
}

u32 aarch64_insn_gen_prefetch(enum aarch64_insn_register base,
                              enum aarch64_insn_prfm_type type,
                              enum aarch64_insn_prfm_target target,
                              enum aarch64_insn_prfm_policy policy)
{
        u32 insn = aarch64_insn_get_prfm_value();

        insn = aarch64_insn_encode_ldst_size(AARCH64_INSN_SIZE_64, insn);

        insn = aarch64_insn_encode_prfm_imm(type, target, policy, insn);

        insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RN, insn,
                                            base);

        return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_12, insn, 0);
}

u32 aarch64_insn_gen_add_sub_imm(enum aarch64_insn_register dst,
                                 enum aarch64_insn_register src,
                                 int imm, enum aarch64_insn_variant variant,
                                 enum aarch64_insn_adsb_type type)
{
        u32 insn;

        switch (type) {
        case AARCH64_INSN_ADSB_ADD:
                insn = aarch64_insn_get_add_imm_value();
                break;
        case AARCH64_INSN_ADSB_SUB:
                insn = aarch64_insn_get_sub_imm_value();
                break;
        case AARCH64_INSN_ADSB_ADD_SETFLAGS:
                insn = aarch64_insn_get_adds_imm_value();
                break;
        case AARCH64_INSN_ADSB_SUB_SETFLAGS:
                insn = aarch64_insn_get_subs_imm_value();
                break;
        default:
                pr_err("%s: unknown add/sub encoding %d\n", __func__, type);
                return AARCH64_BREAK_FAULT;
        }

        switch (variant) {
        case AARCH64_INSN_VARIANT_32BIT:
                break;
        case AARCH64_INSN_VARIANT_64BIT:
                insn |= AARCH64_INSN_SF_BIT;
                break;
        default:
                pr_err("%s: unknown variant encoding %d\n", __func__, variant);
                return AARCH64_BREAK_FAULT;
        }

        /* We can't encode more than a 24bit value (12bit + 12bit shift) */
        if (imm & ~(BIT(24) - 1))
                goto out;

        /* If we have something in the top 12 bits... */
        if (imm & ~(SZ_4K - 1)) {
                /* ... and in the low 12 bits -> error */
                if (imm & (SZ_4K - 1))
                        goto out;

                imm >>= 12;
                insn |= AARCH64_INSN_LSL_12;
        }

        insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RD, insn, dst);

        insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RN, insn, src);

        return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_12, insn, imm);

out:
        pr_err("%s: invalid immediate encoding %d\n", __func__, imm);
        return AARCH64_BREAK_FAULT;
}

u32 aarch64_insn_gen_bitfield(enum aarch64_insn_register dst,
                              enum aarch64_insn_register src,
                              int immr, int imms,
                              enum aarch64_insn_variant variant,
                              enum aarch64_insn_bitfield_type type)
{
        u32 insn;
        u32 mask;

        switch (type) {
        case AARCH64_INSN_BITFIELD_MOVE:
                insn = aarch64_insn_get_bfm_value();
                break;
        case AARCH64_INSN_BITFIELD_MOVE_UNSIGNED:
                insn = aarch64_insn_get_ubfm_value();
                break;
        case AARCH64_INSN_BITFIELD_MOVE_SIGNED:
                insn = aarch64_insn_get_sbfm_value();
                break;
        default:
                pr_err("%s: unknown bitfield encoding %d\n", __func__, type);
                return AARCH64_BREAK_FAULT;
        }

        switch (variant) {
        case AARCH64_INSN_VARIANT_32BIT:
                mask = GENMASK(4, 0);
                break;
        case AARCH64_INSN_VARIANT_64BIT:
                insn |= AARCH64_INSN_SF_BIT | AARCH64_INSN_N_BIT;
                mask = GENMASK(5, 0);
                break;
        default:
                pr_err("%s: unknown variant encoding %d\n", __func__, variant);
                return AARCH64_BREAK_FAULT;
        }

        if (immr & ~mask) {
                pr_err("%s: invalid immr encoding %d\n", __func__, immr);
                return AARCH64_BREAK_FAULT;
        }
        if (imms & ~mask) {
                pr_err("%s: invalid imms encoding %d\n", __func__, imms);
                return AARCH64_BREAK_FAULT;
        }

        insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RD, insn, dst);

        insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RN, insn, src);

        insn = aarch64_insn_encode_immediate(AARCH64_INSN_IMM_R, insn, immr);

        return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_S, insn, imms);
}

u32 aarch64_insn_gen_movewide(enum aarch64_insn_register dst,
                              int imm, int shift,
                              enum aarch64_insn_variant variant,
                              enum aarch64_insn_movewide_type type)
{
        u32 insn;

        switch (type) {
        case AARCH64_INSN_MOVEWIDE_ZERO:
                insn = aarch64_insn_get_movz_value();
                break;
        case AARCH64_INSN_MOVEWIDE_KEEP:
                insn = aarch64_insn_get_movk_value();
                break;
        case AARCH64_INSN_MOVEWIDE_INVERSE:
                insn = aarch64_insn_get_movn_value();
                break;
        default:

                pr_err("%s: unknown movewide encoding %d\n", __func__, type);
                return AARCH64_BREAK_FAULT;
        }

        if (imm & ~(SZ_64K - 1)) {
                pr_err("%s: invalid immediate encoding %d\n", __func__, imm);
                return AARCH64_BREAK_FAULT;
        }

        switch (variant) {
        case AARCH64_INSN_VARIANT_32BIT:
                if (shift != 0 && shift != 16) {
                        pr_err("%s: invalid shift encoding %d\n", __func__,
                               shift);
                        return AARCH64_BREAK_FAULT;
                }
                break;
        case AARCH64_INSN_VARIANT_64BIT:
                insn |= AARCH64_INSN_SF_BIT;
                if (shift != 0 && shift != 16 && shift != 32 && shift != 48) {
                        pr_err("%s: invalid shift encoding %d\n", __func__,
                               shift);
                        return AARCH64_BREAK_FAULT;
                }
                break;
        default:
                pr_err("%s: unknown variant encoding %d\n", __func__, variant);
                return AARCH64_BREAK_FAULT;
        }

        insn |= (shift >> 4) << 21;

        insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RD, insn, dst);

        return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_16, insn, imm);
}

u32 aarch64_insn_gen_add_sub_shifted_reg(enum aarch64_insn_register dst,
                                         enum aarch64_insn_register src,
                                         enum aarch64_insn_register reg,
                                         int shift,
                                         enum aarch64_insn_variant variant,
                                         enum aarch64_insn_adsb_type type)
{
        u32 insn;

        switch (type) {
        case AARCH64_INSN_ADSB_ADD:
                insn = aarch64_insn_get_add_value();
                break;
        case AARCH64_INSN_ADSB_SUB:
                insn = aarch64_insn_get_sub_value();
                break;
        case AARCH64_INSN_ADSB_ADD_SETFLAGS:
                insn = aarch64_insn_get_adds_value();
                break;
        case AARCH64_INSN_ADSB_SUB_SETFLAGS:
                insn = aarch64_insn_get_subs_value();
                break;
        default:
                pr_err("%s: unknown add/sub encoding %d\n", __func__, type);
                return AARCH64_BREAK_FAULT;
        }

        switch (variant) {
        case AARCH64_INSN_VARIANT_32BIT:
                if (shift & ~(SZ_32 - 1)) {
                        pr_err("%s: invalid shift encoding %d\n", __func__,
                               shift);
                        return AARCH64_BREAK_FAULT;
                }
                break;
        case AARCH64_INSN_VARIANT_64BIT:
                insn |= AARCH64_INSN_SF_BIT;
                if (shift & ~(SZ_64 - 1)) {
                        pr_err("%s: invalid shift encoding %d\n", __func__,
                               shift);
                        return AARCH64_BREAK_FAULT;
                }
                break;
        default:
                pr_err("%s: unknown variant encoding %d\n", __func__, variant);
                return AARCH64_BREAK_FAULT;
        }


        insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RD, insn, dst);

        insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RN, insn, src);

        insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RM, insn, reg);

        return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_6, insn, shift);
}

u32 aarch64_insn_gen_data1(enum aarch64_insn_register dst,
                           enum aarch64_insn_register src,
                           enum aarch64_insn_variant variant,
                           enum aarch64_insn_data1_type type)
{
        u32 insn;

        switch (type) {
        case AARCH64_INSN_DATA1_REVERSE_16:
                insn = aarch64_insn_get_rev16_value();
                break;
        case AARCH64_INSN_DATA1_REVERSE_32:
                insn = aarch64_insn_get_rev32_value();
                break;
        case AARCH64_INSN_DATA1_REVERSE_64:
                if (variant != AARCH64_INSN_VARIANT_64BIT) {
                        pr_err("%s: invalid variant for reverse64 %d\n",
                               __func__, variant);
                        return AARCH64_BREAK_FAULT;
                }
                insn = aarch64_insn_get_rev64_value();
                break;
        default:
                pr_err("%s: unknown data1 encoding %d\n", __func__, type);
                return AARCH64_BREAK_FAULT;
        }

        switch (variant) {
        case AARCH64_INSN_VARIANT_32BIT:
                break;
        case AARCH64_INSN_VARIANT_64BIT:
                insn |= AARCH64_INSN_SF_BIT;
                break;
        default:
                pr_err("%s: unknown variant encoding %d\n", __func__, variant);
                return AARCH64_BREAK_FAULT;
        }

        insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RD, insn, dst);

        return aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RN, insn, src);
}

u32 aarch64_insn_gen_data2(enum aarch64_insn_register dst,
                           enum aarch64_insn_register src,
                           enum aarch64_insn_register reg,
                           enum aarch64_insn_variant variant,
                           enum aarch64_insn_data2_type type)
{
        u32 insn;

        switch (type) {
        case AARCH64_INSN_DATA2_UDIV:
                insn = aarch64_insn_get_udiv_value();
                break;
        case AARCH64_INSN_DATA2_SDIV:
                insn = aarch64_insn_get_sdiv_value();
                break;
        case AARCH64_INSN_DATA2_LSLV:
                insn = aarch64_insn_get_lslv_value();
                break;
        case AARCH64_INSN_DATA2_LSRV:
                insn = aarch64_insn_get_lsrv_value();
                break;
        case AARCH64_INSN_DATA2_ASRV:
                insn = aarch64_insn_get_asrv_value();
                break;
        case AARCH64_INSN_DATA2_RORV:
                insn = aarch64_insn_get_rorv_value();
                break;
        default:
                pr_err("%s: unknown data2 encoding %d\n", __func__, type);
                return AARCH64_BREAK_FAULT;
        }

        switch (variant) {
        case AARCH64_INSN_VARIANT_32BIT:
                break;
        case AARCH64_INSN_VARIANT_64BIT:
                insn |= AARCH64_INSN_SF_BIT;
                break;
        default:
                pr_err("%s: unknown variant encoding %d\n", __func__, variant);
                return AARCH64_BREAK_FAULT;
        }

        insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RD, insn, dst);

        insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RN, insn, src);

        return aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RM, insn, reg);
}

u32 aarch64_insn_gen_data3(enum aarch64_insn_register dst,
                           enum aarch64_insn_register src,
                           enum aarch64_insn_register reg1,
                           enum aarch64_insn_register reg2,
                           enum aarch64_insn_variant variant,
                           enum aarch64_insn_data3_type type)
{
        u32 insn;

        switch (type) {
        case AARCH64_INSN_DATA3_MADD:
                insn = aarch64_insn_get_madd_value();
                break;
        case AARCH64_INSN_DATA3_MSUB:
                insn = aarch64_insn_get_msub_value();
                break;
        default:
                pr_err("%s: unknown data3 encoding %d\n", __func__, type);
                return AARCH64_BREAK_FAULT;
        }

        switch (variant) {
        case AARCH64_INSN_VARIANT_32BIT:
                break;
        case AARCH64_INSN_VARIANT_64BIT:
                insn |= AARCH64_INSN_SF_BIT;
                break;
        default:
                pr_err("%s: unknown variant encoding %d\n", __func__, variant);
                return AARCH64_BREAK_FAULT;
        }

        insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RD, insn, dst);

        insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RA, insn, src);

        insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RN, insn,
                                            reg1);

        return aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RM, insn,
                                            reg2);
}

u32 aarch64_insn_gen_logical_shifted_reg(enum aarch64_insn_register dst,
                                         enum aarch64_insn_register src,
                                         enum aarch64_insn_register reg,
                                         int shift,
                                         enum aarch64_insn_variant variant,
                                         enum aarch64_insn_logic_type type)
{
        u32 insn;

        switch (type) {
        case AARCH64_INSN_LOGIC_AND:
                insn = aarch64_insn_get_and_value();
                break;
        case AARCH64_INSN_LOGIC_BIC:
                insn = aarch64_insn_get_bic_value();
                break;
        case AARCH64_INSN_LOGIC_ORR:
                insn = aarch64_insn_get_orr_value();
                break;
        case AARCH64_INSN_LOGIC_ORN:
                insn = aarch64_insn_get_orn_value();
                break;
        case AARCH64_INSN_LOGIC_EOR:
                insn = aarch64_insn_get_eor_value();
                break;
        case AARCH64_INSN_LOGIC_EON:
                insn = aarch64_insn_get_eon_value();
                break;
        case AARCH64_INSN_LOGIC_AND_SETFLAGS:
                insn = aarch64_insn_get_ands_value();
                break;
        case AARCH64_INSN_LOGIC_BIC_SETFLAGS:
                insn = aarch64_insn_get_bics_value();
                break;
        default:
                pr_err("%s: unknown logical encoding %d\n", __func__, type);
                return AARCH64_BREAK_FAULT;
        }

        switch (variant) {
        case AARCH64_INSN_VARIANT_32BIT:
                if (shift & ~(SZ_32 - 1)) {
                        pr_err("%s: invalid shift encoding %d\n", __func__,
                               shift);
                        return AARCH64_BREAK_FAULT;
                }
                break;
        case AARCH64_INSN_VARIANT_64BIT:
                insn |= AARCH64_INSN_SF_BIT;
                if (shift & ~(SZ_64 - 1)) {
                        pr_err("%s: invalid shift encoding %d\n", __func__,
                               shift);
                        return AARCH64_BREAK_FAULT;
                }
                break;
        default:
                pr_err("%s: unknown variant encoding %d\n", __func__, variant);
                return AARCH64_BREAK_FAULT;
        }


        insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RD, insn, dst);

        insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RN, insn, src);

        insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RM, insn, reg);

        return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_6, insn, shift);
}

/*
 * MOV (register) is architecturally an alias of ORR (shifted register) where
 * MOV <*d>, <*m> is equivalent to ORR <*d>, <*ZR>, <*m>
 */
u32 aarch64_insn_gen_move_reg(enum aarch64_insn_register dst,
                              enum aarch64_insn_register src,
                              enum aarch64_insn_variant variant)
{
        return aarch64_insn_gen_logical_shifted_reg(dst, AARCH64_INSN_REG_ZR,
                                                    src, 0, variant,
                                                    AARCH64_INSN_LOGIC_ORR);
}

u32 aarch64_insn_gen_adr(unsigned long pc, unsigned long addr,
                         enum aarch64_insn_register reg,
                         enum aarch64_insn_adr_type type)
{
        u32 insn;
        s32 offset;

        switch (type) {
        case AARCH64_INSN_ADR_TYPE_ADR:
                insn = aarch64_insn_get_adr_value();
                offset = addr - pc;
                break;
        case AARCH64_INSN_ADR_TYPE_ADRP:
                insn = aarch64_insn_get_adrp_value();
                offset = (addr - ALIGN_DOWN(pc, SZ_4K)) >> 12;
                break;
        default:
                pr_err("%s: unknown adr encoding %d\n", __func__, type);
                return AARCH64_BREAK_FAULT;
        }

        if (offset < -SZ_1M || offset >= SZ_1M)
                return AARCH64_BREAK_FAULT;

        insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RD, insn, reg);

        return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_ADR, insn, offset);
}

/*
 * Decode the imm field of a branch, and return the byte offset as a
 * signed value (so it can be used when computing a new branch
 * target).
 */
s32 aarch64_get_branch_offset(u32 insn)
{
        s32 imm;

        if (aarch64_insn_is_b(insn) || aarch64_insn_is_bl(insn)) {
                imm = aarch64_insn_decode_immediate(AARCH64_INSN_IMM_26, insn);
                return (imm << 6) >> 4;
        }

        if (aarch64_insn_is_cbz(insn) || aarch64_insn_is_cbnz(insn) ||
            aarch64_insn_is_bcond(insn)) {
                imm = aarch64_insn_decode_immediate(AARCH64_INSN_IMM_19, insn);
                return (imm << 13) >> 11;
        }

        if (aarch64_insn_is_tbz(insn) || aarch64_insn_is_tbnz(insn)) {
                imm = aarch64_insn_decode_immediate(AARCH64_INSN_IMM_14, insn);
                return (imm << 18) >> 16;
        }

        /* Unhandled instruction */
        BUG();
}

/*
 * Encode the displacement of a branch in the imm field and return the
 * updated instruction.
 */
u32 aarch64_set_branch_offset(u32 insn, s32 offset)
{
        if (aarch64_insn_is_b(insn) || aarch64_insn_is_bl(insn))
                return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_26, insn,
                                                     offset >> 2);

        if (aarch64_insn_is_cbz(insn) || aarch64_insn_is_cbnz(insn) ||
            aarch64_insn_is_bcond(insn))
                return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_19, insn,
                                                     offset >> 2);

        if (aarch64_insn_is_tbz(insn) || aarch64_insn_is_tbnz(insn))
                return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_14, insn,
                                                     offset >> 2);

        /* Unhandled instruction */
        BUG();
}

s32 aarch64_insn_adrp_get_offset(u32 insn)
{
        BUG_ON(!aarch64_insn_is_adrp(insn));
        return aarch64_insn_decode_immediate(AARCH64_INSN_IMM_ADR, insn) << 12;
}

u32 aarch64_insn_adrp_set_offset(u32 insn, s32 offset)
{
        BUG_ON(!aarch64_insn_is_adrp(insn));
        return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_ADR, insn,
                                                offset >> 12);
}

/*
 * Extract the Op/CR data from a msr/mrs instruction.
 */
u32 aarch64_insn_extract_system_reg(u32 insn)
{
        return (insn & 0x1FFFE0) >> 5;
}

bool aarch32_insn_is_wide(u32 insn)
{
        return insn >= 0xe800;
}

/*
 * Macros/defines for extracting register numbers from instruction.
 */
u32 aarch32_insn_extract_reg_num(u32 insn, int offset)
{
        return (insn & (0xf << offset)) >> offset;
}

#define OPC2_MASK       0x7
#define OPC2_OFFSET     5
u32 aarch32_insn_mcr_extract_opc2(u32 insn)
{
        return (insn & (OPC2_MASK << OPC2_OFFSET)) >> OPC2_OFFSET;
}

#define CRM_MASK        0xf
u32 aarch32_insn_mcr_extract_crm(u32 insn)
{
        return insn & CRM_MASK;
}

static bool range_of_ones(u64 val)
{
        /* Doesn't handle full ones or full zeroes */
        u64 sval = val >> __ffs64(val);

        /* One of Sean Eron Anderson's bithack tricks */
        return ((sval + 1) & (sval)) == 0;
}

static u32 aarch64_encode_immediate(u64 imm,
                                    enum aarch64_insn_variant variant,
                                    u32 insn)
{
        unsigned int immr, imms, n, ones, ror, esz, tmp;
        u64 mask;

        switch (variant) {
        case AARCH64_INSN_VARIANT_32BIT:
                esz = 32;
                break;
        case AARCH64_INSN_VARIANT_64BIT:
                insn |= AARCH64_INSN_SF_BIT;
                esz = 64;
                break;
        default:
                pr_err("%s: unknown variant encoding %d\n", __func__, variant);
                return AARCH64_BREAK_FAULT;
        }

        mask = GENMASK(esz - 1, 0);

        /* Can't encode full zeroes, full ones, or value wider than the mask */
        if (!imm || imm == mask || imm & ~mask)
                return AARCH64_BREAK_FAULT;

        /*
         * Inverse of Replicate(). Try to spot a repeating pattern
         * with a pow2 stride.
         */
        for (tmp = esz / 2; tmp >= 2; tmp /= 2) {
                u64 emask = BIT(tmp) - 1;

                if ((imm & emask) != ((imm >> tmp) & emask))
                        break;

                esz = tmp;
                mask = emask;
        }

        /* N is only set if we're encoding a 64bit value */
        n = esz == 64;

        /* Trim imm to the element size */
        imm &= mask;

        /* That's how many ones we need to encode */
        ones = hweight64(imm);

        /*
         * imms is set to (ones - 1), prefixed with a string of ones
         * and a zero if they fit. Cap it to 6 bits.
         */
        imms  = ones - 1;
        imms |= 0xf << ffs(esz);
        imms &= BIT(6) - 1;

        /* Compute the rotation */
        if (range_of_ones(imm)) {
                /*
                 * Pattern: 0..01..10..0
                 *
                 * Compute how many rotate we need to align it right
                 */
                ror = __ffs64(imm);
        } else {
                /*
                 * Pattern: 0..01..10..01..1
                 *
                 * Fill the unused top bits with ones, and check if
                 * the result is a valid immediate (all ones with a
                 * contiguous ranges of zeroes).
                 */
                imm |= ~mask;
                if (!range_of_ones(~imm))
                        return AARCH64_BREAK_FAULT;

                /*
                 * Compute the rotation to get a continuous set of
                 * ones, with the first bit set at position 0
                 */
                ror = fls64(~imm);
        }

        /*
         * immr is the number of bits we need to rotate back to the
         * original set of ones. Note that this is relative to the
         * element size...
         */
        immr = (esz - ror) % esz;

        insn = aarch64_insn_encode_immediate(AARCH64_INSN_IMM_N, insn, n);
        insn = aarch64_insn_encode_immediate(AARCH64_INSN_IMM_R, insn, immr);
        return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_S, insn, imms);
}

u32 aarch64_insn_gen_logical_immediate(enum aarch64_insn_logic_type type,
                                       enum aarch64_insn_variant variant,
                                       enum aarch64_insn_register Rn,
                                       enum aarch64_insn_register Rd,
                                       u64 imm)
{
        u32 insn;

        switch (type) {
        case AARCH64_INSN_LOGIC_AND:
                insn = aarch64_insn_get_and_imm_value();
                break;
        case AARCH64_INSN_LOGIC_ORR:
                insn = aarch64_insn_get_orr_imm_value();
                break;
        case AARCH64_INSN_LOGIC_EOR:
                insn = aarch64_insn_get_eor_imm_value();
                break;
        case AARCH64_INSN_LOGIC_AND_SETFLAGS:
                insn = aarch64_insn_get_ands_imm_value();
                break;
        default:
                pr_err("%s: unknown logical encoding %d\n", __func__, type);
                return AARCH64_BREAK_FAULT;
        }

        insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RD, insn, Rd);
        insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RN, insn, Rn);
        return aarch64_encode_immediate(imm, variant, insn);
}

u32 aarch64_insn_gen_extr(enum aarch64_insn_variant variant,
                          enum aarch64_insn_register Rm,
                          enum aarch64_insn_register Rn,
                          enum aarch64_insn_register Rd,
                          u8 lsb)
{
        u32 insn;

        insn = aarch64_insn_get_extr_value();

        switch (variant) {
        case AARCH64_INSN_VARIANT_32BIT:
                if (lsb > 31)
                        return AARCH64_BREAK_FAULT;
                break;
        case AARCH64_INSN_VARIANT_64BIT:
                if (lsb > 63)
                        return AARCH64_BREAK_FAULT;
                insn |= AARCH64_INSN_SF_BIT;
                insn = aarch64_insn_encode_immediate(AARCH64_INSN_IMM_N, insn, 1);
                break;
        default:
                pr_err("%s: unknown variant encoding %d\n", __func__, variant);
                return AARCH64_BREAK_FAULT;
        }

        insn = aarch64_insn_encode_immediate(AARCH64_INSN_IMM_S, insn, lsb);
        insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RD, insn, Rd);
        insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RN, insn, Rn);
        return aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RM, insn, Rm);
}

u32 aarch64_insn_gen_dmb(enum aarch64_insn_mb_type type)
{
        u32 opt;
        u32 insn;

        switch (type) {
        case AARCH64_INSN_MB_SY:
                opt = 0xf;
                break;
        case AARCH64_INSN_MB_ST:
                opt = 0xe;
                break;
        case AARCH64_INSN_MB_LD:
                opt = 0xd;
                break;
        case AARCH64_INSN_MB_ISH:
                opt = 0xb;
                break;
        case AARCH64_INSN_MB_ISHST:
                opt = 0xa;
                break;
        case AARCH64_INSN_MB_ISHLD:
                opt = 0x9;
                break;
        case AARCH64_INSN_MB_NSH:
                opt = 0x7;
                break;
        case AARCH64_INSN_MB_NSHST:
                opt = 0x6;
                break;
        case AARCH64_INSN_MB_NSHLD:
                opt = 0x5;
                break;
        default:
                pr_err("%s: unknown dmb type %d\n", __func__, type);
                return AARCH64_BREAK_FAULT;
        }

        insn = aarch64_insn_get_dmb_value();
        insn &= ~GENMASK(11, 8);
        insn |= (opt << 8);

        return insn;
}