root/arch/mips/kernel/mips-r2-to-r6-emul.c
/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (c) 2014 Imagination Technologies Ltd.
 * Author: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
 * Author: Markos Chandras <markos.chandras@imgtec.com>
 *
 *      MIPS R2 user space instruction emulator for MIPS R6
 *
 */
#include <linux/bug.h>
#include <linux/compiler.h>
#include <linux/debugfs.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/ptrace.h>
#include <linux/seq_file.h>

#include <asm/asm.h>
#include <asm/branch.h>
#include <asm/break.h>
#include <asm/debug.h>
#include <asm/fpu.h>
#include <asm/fpu_emulator.h>
#include <asm/inst.h>
#include <asm/mips-r2-to-r6-emul.h>
#include <asm/local.h>
#include <asm/mipsregs.h>
#include <asm/ptrace.h>
#include <linux/uaccess.h>

#ifdef CONFIG_64BIT
#define ADDIU   "daddiu "
#define INS     "dins "
#define EXT     "dext "
#else
#define ADDIU   "addiu "
#define INS     "ins "
#define EXT     "ext "
#endif /* CONFIG_64BIT */

#define SB      "sb "
#define LB      "lb "
#define LL      "ll "
#define SC      "sc "

#ifdef CONFIG_DEBUG_FS
static DEFINE_PER_CPU(struct mips_r2_emulator_stats, mipsr2emustats);
static DEFINE_PER_CPU(struct mips_r2_emulator_stats, mipsr2bdemustats);
static DEFINE_PER_CPU(struct mips_r2br_emulator_stats, mipsr2bremustats);
#endif

extern const unsigned int fpucondbit[8];

#define MIPS_R2_EMUL_TOTAL_PASS 10

int mipsr2_emulation = 0;

static int __init mipsr2emu_enable(char *s)
{
        mipsr2_emulation = 1;

        pr_info("MIPS R2-to-R6 Emulator Enabled!");

        return 1;
}
__setup("mipsr2emu", mipsr2emu_enable);

/**
 * mipsr6_emul - Emulate some frequent R2/R5/R6 instructions in delay slot
 * for performance instead of the traditional way of using a stack trampoline
 * which is rather slow.
 * @regs: Process register set
 * @ir: Instruction
 */
static inline int mipsr6_emul(struct pt_regs *regs, u32 ir)
{
        switch (MIPSInst_OPCODE(ir)) {
        case addiu_op:
                if (MIPSInst_RT(ir))
                        regs->regs[MIPSInst_RT(ir)] =
                                (s32)regs->regs[MIPSInst_RS(ir)] +
                                (s32)MIPSInst_SIMM(ir);
                return 0;
        case daddiu_op:
                if (IS_ENABLED(CONFIG_32BIT))
                        break;

                if (MIPSInst_RT(ir))
                        regs->regs[MIPSInst_RT(ir)] =
                                (s64)regs->regs[MIPSInst_RS(ir)] +
                                (s64)MIPSInst_SIMM(ir);
                return 0;
        case lwc1_op:
        case swc1_op:
        case cop1_op:
        case cop1x_op:
                /* FPU instructions in delay slot */
                return -SIGFPE;
        case spec_op:
                switch (MIPSInst_FUNC(ir)) {
                case or_op:
                        if (MIPSInst_RD(ir))
                                regs->regs[MIPSInst_RD(ir)] =
                                        regs->regs[MIPSInst_RS(ir)] |
                                        regs->regs[MIPSInst_RT(ir)];
                        return 0;
                case sll_op:
                        if (MIPSInst_RS(ir))
                                break;

                        if (MIPSInst_RD(ir))
                                regs->regs[MIPSInst_RD(ir)] =
                                        (s32)(((u32)regs->regs[MIPSInst_RT(ir)]) <<
                                                MIPSInst_FD(ir));
                        return 0;
                case srl_op:
                        if (MIPSInst_RS(ir))
                                break;

                        if (MIPSInst_RD(ir))
                                regs->regs[MIPSInst_RD(ir)] =
                                        (s32)(((u32)regs->regs[MIPSInst_RT(ir)]) >>
                                                MIPSInst_FD(ir));
                        return 0;
                case addu_op:
                        if (MIPSInst_FD(ir))
                                break;

                        if (MIPSInst_RD(ir))
                                regs->regs[MIPSInst_RD(ir)] =
                                        (s32)((u32)regs->regs[MIPSInst_RS(ir)] +
                                              (u32)regs->regs[MIPSInst_RT(ir)]);
                        return 0;
                case subu_op:
                        if (MIPSInst_FD(ir))
                                break;

                        if (MIPSInst_RD(ir))
                                regs->regs[MIPSInst_RD(ir)] =
                                        (s32)((u32)regs->regs[MIPSInst_RS(ir)] -
                                              (u32)regs->regs[MIPSInst_RT(ir)]);
                        return 0;
                case dsll_op:
                        if (IS_ENABLED(CONFIG_32BIT) || MIPSInst_RS(ir))
                                break;

                        if (MIPSInst_RD(ir))
                                regs->regs[MIPSInst_RD(ir)] =
                                        (s64)(((u64)regs->regs[MIPSInst_RT(ir)]) <<
                                                MIPSInst_FD(ir));
                        return 0;
                case dsrl_op:
                        if (IS_ENABLED(CONFIG_32BIT) || MIPSInst_RS(ir))
                                break;

                        if (MIPSInst_RD(ir))
                                regs->regs[MIPSInst_RD(ir)] =
                                        (s64)(((u64)regs->regs[MIPSInst_RT(ir)]) >>
                                                MIPSInst_FD(ir));
                        return 0;
                case daddu_op:
                        if (IS_ENABLED(CONFIG_32BIT) || MIPSInst_FD(ir))
                                break;

                        if (MIPSInst_RD(ir))
                                regs->regs[MIPSInst_RD(ir)] =
                                        (u64)regs->regs[MIPSInst_RS(ir)] +
                                        (u64)regs->regs[MIPSInst_RT(ir)];
                        return 0;
                case dsubu_op:
                        if (IS_ENABLED(CONFIG_32BIT) || MIPSInst_FD(ir))
                                break;

                        if (MIPSInst_RD(ir))
                                regs->regs[MIPSInst_RD(ir)] =
                                        (s64)((u64)regs->regs[MIPSInst_RS(ir)] -
                                              (u64)regs->regs[MIPSInst_RT(ir)]);
                        return 0;
                }
                break;
        default:
                pr_debug("No fastpath BD emulation for instruction 0x%08x (op: %02x)\n",
                         ir, MIPSInst_OPCODE(ir));
        }

        return SIGILL;
}

/**
 * movf_func - Emulate a MOVF instruction
 * @regs: Process register set
 * @ir: Instruction
 *
 * Returns 0 since it always succeeds.
 */
static int movf_func(struct pt_regs *regs, u32 ir)
{
        u32 csr;
        u32 cond;

        csr = current->thread.fpu.fcr31;
        cond = fpucondbit[MIPSInst_RT(ir) >> 2];

        if (((csr & cond) == 0) && MIPSInst_RD(ir))
                regs->regs[MIPSInst_RD(ir)] = regs->regs[MIPSInst_RS(ir)];

        MIPS_R2_STATS(movs);

        return 0;
}

/**
 * movt_func - Emulate a MOVT instruction
 * @regs: Process register set
 * @ir: Instruction
 *
 * Returns 0 since it always succeeds.
 */
static int movt_func(struct pt_regs *regs, u32 ir)
{
        u32 csr;
        u32 cond;

        csr = current->thread.fpu.fcr31;
        cond = fpucondbit[MIPSInst_RT(ir) >> 2];

        if (((csr & cond) != 0) && MIPSInst_RD(ir))
                regs->regs[MIPSInst_RD(ir)] = regs->regs[MIPSInst_RS(ir)];

        MIPS_R2_STATS(movs);

        return 0;
}

/**
 * jr_func - Emulate a JR instruction.
 * @pt_regs: Process register set
 * @ir: Instruction
 *
 * Returns SIGILL if JR was in delay slot, SIGEMT if we
 * can't compute the EPC, SIGSEGV if we can't access the
 * userland instruction or 0 on success.
 */
static int jr_func(struct pt_regs *regs, u32 ir)
{
        int err;
        unsigned long cepc, epc, nepc;
        u32 nir;

        if (delay_slot(regs))
                return SIGILL;

        /* EPC after the RI/JR instruction */
        nepc = regs->cp0_epc;
        /* Roll back to the reserved R2 JR instruction */
        regs->cp0_epc -= 4;
        epc = regs->cp0_epc;
        err = __compute_return_epc(regs);

        if (err < 0)
                return SIGEMT;


        /* Computed EPC */
        cepc = regs->cp0_epc;

        /* Get DS instruction */
        err = __get_user(nir, (u32 __user *)nepc);
        if (err)
                return SIGSEGV;

        MIPS_R2BR_STATS(jrs);

        /* If nir == 0(NOP), then nothing else to do */
        if (nir) {
                /*
                 * Negative err means FPU instruction in BD-slot,
                 * Zero err means 'BD-slot emulation done'
                 * For anything else we go back to trampoline emulation.
                 */
                err = mipsr6_emul(regs, nir);
                if (err > 0) {
                        regs->cp0_epc = nepc;
                        err = mips_dsemul(regs, nir, epc, cepc);
                        if (err == SIGILL)
                                err = SIGEMT;
                        MIPS_R2_STATS(dsemul);
                }
        }

        return err;
}

/**
 * movz_func - Emulate a MOVZ instruction
 * @regs: Process register set
 * @ir: Instruction
 *
 * Returns 0 since it always succeeds.
 */
static int movz_func(struct pt_regs *regs, u32 ir)
{
        if (((regs->regs[MIPSInst_RT(ir)]) == 0) && MIPSInst_RD(ir))
                regs->regs[MIPSInst_RD(ir)] = regs->regs[MIPSInst_RS(ir)];
        MIPS_R2_STATS(movs);

        return 0;
}

/**
 * movn_func - Emulate a MOVZ instruction
 * @regs: Process register set
 * @ir: Instruction
 *
 * Returns 0 since it always succeeds.
 */
static int movn_func(struct pt_regs *regs, u32 ir)
{
        if (((regs->regs[MIPSInst_RT(ir)]) != 0) && MIPSInst_RD(ir))
                regs->regs[MIPSInst_RD(ir)] = regs->regs[MIPSInst_RS(ir)];
        MIPS_R2_STATS(movs);

        return 0;
}

/**
 * mfhi_func - Emulate a MFHI instruction
 * @regs: Process register set
 * @ir: Instruction
 *
 * Returns 0 since it always succeeds.
 */
static int mfhi_func(struct pt_regs *regs, u32 ir)
{
        if (MIPSInst_RD(ir))
                regs->regs[MIPSInst_RD(ir)] = regs->hi;

        MIPS_R2_STATS(hilo);

        return 0;
}

/**
 * mthi_func - Emulate a MTHI instruction
 * @regs: Process register set
 * @ir: Instruction
 *
 * Returns 0 since it always succeeds.
 */
static int mthi_func(struct pt_regs *regs, u32 ir)
{
        regs->hi = regs->regs[MIPSInst_RS(ir)];

        MIPS_R2_STATS(hilo);

        return 0;
}

/**
 * mflo_func - Emulate a MFLO instruction
 * @regs: Process register set
 * @ir: Instruction
 *
 * Returns 0 since it always succeeds.
 */
static int mflo_func(struct pt_regs *regs, u32 ir)
{
        if (MIPSInst_RD(ir))
                regs->regs[MIPSInst_RD(ir)] = regs->lo;

        MIPS_R2_STATS(hilo);

        return 0;
}

/**
 * mtlo_func - Emulate a MTLO instruction
 * @regs: Process register set
 * @ir: Instruction
 *
 * Returns 0 since it always succeeds.
 */
static int mtlo_func(struct pt_regs *regs, u32 ir)
{
        regs->lo = regs->regs[MIPSInst_RS(ir)];

        MIPS_R2_STATS(hilo);

        return 0;
}

/**
 * mult_func - Emulate a MULT instruction
 * @regs: Process register set
 * @ir: Instruction
 *
 * Returns 0 since it always succeeds.
 */
static int mult_func(struct pt_regs *regs, u32 ir)
{
        s64 res;
        s32 rt, rs;

        rt = regs->regs[MIPSInst_RT(ir)];
        rs = regs->regs[MIPSInst_RS(ir)];
        res = (s64)rt * (s64)rs;

        rs = res;
        regs->lo = (s64)rs;
        rt = res >> 32;
        res = (s64)rt;
        regs->hi = res;

        MIPS_R2_STATS(muls);

        return 0;
}

/**
 * multu_func - Emulate a MULTU instruction
 * @regs: Process register set
 * @ir: Instruction
 *
 * Returns 0 since it always succeeds.
 */
static int multu_func(struct pt_regs *regs, u32 ir)
{
        u64 res;
        u32 rt, rs;

        rt = regs->regs[MIPSInst_RT(ir)];
        rs = regs->regs[MIPSInst_RS(ir)];
        res = (u64)rt * (u64)rs;
        rt = res;
        regs->lo = (s64)(s32)rt;
        regs->hi = (s64)(s32)(res >> 32);

        MIPS_R2_STATS(muls);

        return 0;
}

/**
 * div_func - Emulate a DIV instruction
 * @regs: Process register set
 * @ir: Instruction
 *
 * Returns 0 since it always succeeds.
 */
static int div_func(struct pt_regs *regs, u32 ir)
{
        s32 rt, rs;

        rt = regs->regs[MIPSInst_RT(ir)];
        rs = regs->regs[MIPSInst_RS(ir)];

        regs->lo = (s64)(rs / rt);
        regs->hi = (s64)(rs % rt);

        MIPS_R2_STATS(divs);

        return 0;
}

/**
 * divu_func - Emulate a DIVU instruction
 * @regs: Process register set
 * @ir: Instruction
 *
 * Returns 0 since it always succeeds.
 */
static int divu_func(struct pt_regs *regs, u32 ir)
{
        u32 rt, rs;

        rt = regs->regs[MIPSInst_RT(ir)];
        rs = regs->regs[MIPSInst_RS(ir)];

        regs->lo = (s64)(rs / rt);
        regs->hi = (s64)(rs % rt);

        MIPS_R2_STATS(divs);

        return 0;
}

/**
 * dmult_func - Emulate a DMULT instruction
 * @regs: Process register set
 * @ir: Instruction
 *
 * Returns 0 on success or SIGILL for 32-bit kernels.
 */
static int dmult_func(struct pt_regs *regs, u32 ir)
{
        s64 res;
        s64 rt, rs;

        if (IS_ENABLED(CONFIG_32BIT))
                return SIGILL;

        rt = regs->regs[MIPSInst_RT(ir)];
        rs = regs->regs[MIPSInst_RS(ir)];
        res = rt * rs;

        regs->lo = res;
        __asm__ __volatile__(
                "dmuh %0, %1, %2\t\n"
                : "=r"(res)
                : "r"(rt), "r"(rs));

        regs->hi = res;

        MIPS_R2_STATS(muls);

        return 0;
}

/**
 * dmultu_func - Emulate a DMULTU instruction
 * @regs: Process register set
 * @ir: Instruction
 *
 * Returns 0 on success or SIGILL for 32-bit kernels.
 */
static int dmultu_func(struct pt_regs *regs, u32 ir)
{
        u64 res;
        u64 rt, rs;

        if (IS_ENABLED(CONFIG_32BIT))
                return SIGILL;

        rt = regs->regs[MIPSInst_RT(ir)];
        rs = regs->regs[MIPSInst_RS(ir)];
        res = rt * rs;

        regs->lo = res;
        __asm__ __volatile__(
                "dmuhu %0, %1, %2\t\n"
                : "=r"(res)
                : "r"(rt), "r"(rs));

        regs->hi = res;

        MIPS_R2_STATS(muls);

        return 0;
}

/**
 * ddiv_func - Emulate a DDIV instruction
 * @regs: Process register set
 * @ir: Instruction
 *
 * Returns 0 on success or SIGILL for 32-bit kernels.
 */
static int ddiv_func(struct pt_regs *regs, u32 ir)
{
        s64 rt, rs;

        if (IS_ENABLED(CONFIG_32BIT))
                return SIGILL;

        rt = regs->regs[MIPSInst_RT(ir)];
        rs = regs->regs[MIPSInst_RS(ir)];

        regs->lo = rs / rt;
        regs->hi = rs % rt;

        MIPS_R2_STATS(divs);

        return 0;
}

/**
 * ddivu_func - Emulate a DDIVU instruction
 * @regs: Process register set
 * @ir: Instruction
 *
 * Returns 0 on success or SIGILL for 32-bit kernels.
 */
static int ddivu_func(struct pt_regs *regs, u32 ir)
{
        u64 rt, rs;

        if (IS_ENABLED(CONFIG_32BIT))
                return SIGILL;

        rt = regs->regs[MIPSInst_RT(ir)];
        rs = regs->regs[MIPSInst_RS(ir)];

        regs->lo = rs / rt;
        regs->hi = rs % rt;

        MIPS_R2_STATS(divs);

        return 0;
}

/* R6 removed instructions for the SPECIAL opcode */
static const struct r2_decoder_table spec_op_table[] = {
        { 0xfc1ff83f, 0x00000008, jr_func },
        { 0xfc00ffff, 0x00000018, mult_func },
        { 0xfc00ffff, 0x00000019, multu_func },
        { 0xfc00ffff, 0x0000001c, dmult_func },
        { 0xfc00ffff, 0x0000001d, dmultu_func },
        { 0xffff07ff, 0x00000010, mfhi_func },
        { 0xfc1fffff, 0x00000011, mthi_func },
        { 0xffff07ff, 0x00000012, mflo_func },
        { 0xfc1fffff, 0x00000013, mtlo_func },
        { 0xfc0307ff, 0x00000001, movf_func },
        { 0xfc0307ff, 0x00010001, movt_func },
        { 0xfc0007ff, 0x0000000a, movz_func },
        { 0xfc0007ff, 0x0000000b, movn_func },
        { 0xfc00ffff, 0x0000001a, div_func },
        { 0xfc00ffff, 0x0000001b, divu_func },
        { 0xfc00ffff, 0x0000001e, ddiv_func },
        { 0xfc00ffff, 0x0000001f, ddivu_func },
        {}
};

/**
 * madd_func - Emulate a MADD instruction
 * @regs: Process register set
 * @ir: Instruction
 *
 * Returns 0 since it always succeeds.
 */
static int madd_func(struct pt_regs *regs, u32 ir)
{
        s64 res;
        s32 rt, rs;

        rt = regs->regs[MIPSInst_RT(ir)];
        rs = regs->regs[MIPSInst_RS(ir)];
        res = (s64)rt * (s64)rs;
        rt = regs->hi;
        rs = regs->lo;
        res += ((((s64)rt) << 32) | (u32)rs);

        rt = res;
        regs->lo = (s64)rt;
        rs = res >> 32;
        regs->hi = (s64)rs;

        MIPS_R2_STATS(dsps);

        return 0;
}

/**
 * maddu_func - Emulate a MADDU instruction
 * @regs: Process register set
 * @ir: Instruction
 *
 * Returns 0 since it always succeeds.
 */
static int maddu_func(struct pt_regs *regs, u32 ir)
{
        u64 res;
        u32 rt, rs;

        rt = regs->regs[MIPSInst_RT(ir)];
        rs = regs->regs[MIPSInst_RS(ir)];
        res = (u64)rt * (u64)rs;
        rt = regs->hi;
        rs = regs->lo;
        res += ((((s64)rt) << 32) | (u32)rs);

        rt = res;
        regs->lo = (s64)(s32)rt;
        rs = res >> 32;
        regs->hi = (s64)(s32)rs;

        MIPS_R2_STATS(dsps);

        return 0;
}

/**
 * msub_func - Emulate a MSUB instruction
 * @regs: Process register set
 * @ir: Instruction
 *
 * Returns 0 since it always succeeds.
 */
static int msub_func(struct pt_regs *regs, u32 ir)
{
        s64 res;
        s32 rt, rs;

        rt = regs->regs[MIPSInst_RT(ir)];
        rs = regs->regs[MIPSInst_RS(ir)];
        res = (s64)rt * (s64)rs;
        rt = regs->hi;
        rs = regs->lo;
        res = ((((s64)rt) << 32) | (u32)rs) - res;

        rt = res;
        regs->lo = (s64)rt;
        rs = res >> 32;
        regs->hi = (s64)rs;

        MIPS_R2_STATS(dsps);

        return 0;
}

/**
 * msubu_func - Emulate a MSUBU instruction
 * @regs: Process register set
 * @ir: Instruction
 *
 * Returns 0 since it always succeeds.
 */
static int msubu_func(struct pt_regs *regs, u32 ir)
{
        u64 res;
        u32 rt, rs;

        rt = regs->regs[MIPSInst_RT(ir)];
        rs = regs->regs[MIPSInst_RS(ir)];
        res = (u64)rt * (u64)rs;
        rt = regs->hi;
        rs = regs->lo;
        res = ((((s64)rt) << 32) | (u32)rs) - res;

        rt = res;
        regs->lo = (s64)(s32)rt;
        rs = res >> 32;
        regs->hi = (s64)(s32)rs;

        MIPS_R2_STATS(dsps);

        return 0;
}

/**
 * mul_func - Emulate a MUL instruction
 * @regs: Process register set
 * @ir: Instruction
 *
 * Returns 0 since it always succeeds.
 */
static int mul_func(struct pt_regs *regs, u32 ir)
{
        s64 res;
        s32 rt, rs;

        if (!MIPSInst_RD(ir))
                return 0;
        rt = regs->regs[MIPSInst_RT(ir)];
        rs = regs->regs[MIPSInst_RS(ir)];
        res = (s64)rt * (s64)rs;

        rs = res;
        regs->regs[MIPSInst_RD(ir)] = (s64)rs;

        MIPS_R2_STATS(muls);

        return 0;
}

/**
 * clz_func - Emulate a CLZ instruction
 * @regs: Process register set
 * @ir: Instruction
 *
 * Returns 0 since it always succeeds.
 */
static int clz_func(struct pt_regs *regs, u32 ir)
{
        u32 res;
        u32 rs;

        if (!MIPSInst_RD(ir))
                return 0;

        rs = regs->regs[MIPSInst_RS(ir)];
        __asm__ __volatile__("clz %0, %1" : "=r"(res) : "r"(rs));
        regs->regs[MIPSInst_RD(ir)] = res;

        MIPS_R2_STATS(bops);

        return 0;
}

/**
 * clo_func - Emulate a CLO instruction
 * @regs: Process register set
 * @ir: Instruction
 *
 * Returns 0 since it always succeeds.
 */

static int clo_func(struct pt_regs *regs, u32 ir)
{
        u32 res;
        u32 rs;

        if (!MIPSInst_RD(ir))
                return 0;

        rs = regs->regs[MIPSInst_RS(ir)];
        __asm__ __volatile__("clo %0, %1" : "=r"(res) : "r"(rs));
        regs->regs[MIPSInst_RD(ir)] = res;

        MIPS_R2_STATS(bops);

        return 0;
}

/**
 * dclz_func - Emulate a DCLZ instruction
 * @regs: Process register set
 * @ir: Instruction
 *
 * Returns 0 since it always succeeds.
 */
static int dclz_func(struct pt_regs *regs, u32 ir)
{
        u64 res;
        u64 rs;

        if (IS_ENABLED(CONFIG_32BIT))
                return SIGILL;

        if (!MIPSInst_RD(ir))
                return 0;

        rs = regs->regs[MIPSInst_RS(ir)];
        __asm__ __volatile__("dclz %0, %1" : "=r"(res) : "r"(rs));
        regs->regs[MIPSInst_RD(ir)] = res;

        MIPS_R2_STATS(bops);

        return 0;
}

/**
 * dclo_func - Emulate a DCLO instruction
 * @regs: Process register set
 * @ir: Instruction
 *
 * Returns 0 since it always succeeds.
 */
static int dclo_func(struct pt_regs *regs, u32 ir)
{
        u64 res;
        u64 rs;

        if (IS_ENABLED(CONFIG_32BIT))
                return SIGILL;

        if (!MIPSInst_RD(ir))
                return 0;

        rs = regs->regs[MIPSInst_RS(ir)];
        __asm__ __volatile__("dclo %0, %1" : "=r"(res) : "r"(rs));
        regs->regs[MIPSInst_RD(ir)] = res;

        MIPS_R2_STATS(bops);

        return 0;
}

/* R6 removed instructions for the SPECIAL2 opcode */
static const struct r2_decoder_table spec2_op_table[] = {
        { 0xfc00ffff, 0x70000000, madd_func },
        { 0xfc00ffff, 0x70000001, maddu_func },
        { 0xfc0007ff, 0x70000002, mul_func },
        { 0xfc00ffff, 0x70000004, msub_func },
        { 0xfc00ffff, 0x70000005, msubu_func },
        { 0xfc0007ff, 0x70000020, clz_func },
        { 0xfc0007ff, 0x70000021, clo_func },
        { 0xfc0007ff, 0x70000024, dclz_func },
        { 0xfc0007ff, 0x70000025, dclo_func },
        { }
};

static inline int mipsr2_find_op_func(struct pt_regs *regs, u32 inst,
                                      const struct r2_decoder_table *table)
{
        const struct r2_decoder_table *p;
        int err;

        for (p = table; p->func; p++) {
                if ((inst & p->mask) == p->code) {
                        err = (p->func)(regs, inst);
                        return err;
                }
        }
        return SIGILL;
}

/**
 * mipsr2_decoder: Decode and emulate a MIPS R2 instruction
 * @regs: Process register set
 * @inst: Instruction to decode and emulate
 * @fcr31: Floating Point Control and Status Register Cause bits returned
 */
int mipsr2_decoder(struct pt_regs *regs, u32 inst, unsigned long *fcr31)
{
        int err = 0;
        unsigned long vaddr;
        u32 nir;
        unsigned long cpc, epc, nepc, r31, res, rs, rt;

        void __user *fault_addr = NULL;
        int pass = 0;

repeat:
        r31 = regs->regs[31];
        epc = regs->cp0_epc;
        err = compute_return_epc(regs);
        if (err < 0) {
                BUG();
                return SIGEMT;
        }
        pr_debug("Emulating the 0x%08x R2 instruction @ 0x%08lx (pass=%d))\n",
                 inst, epc, pass);

        switch (MIPSInst_OPCODE(inst)) {
        case spec_op:
                err = mipsr2_find_op_func(regs, inst, spec_op_table);
                if (err < 0) {
                        /* FPU instruction under JR */
                        regs->cp0_cause |= CAUSEF_BD;
                        goto fpu_emul;
                }
                break;
        case spec2_op:
                err = mipsr2_find_op_func(regs, inst, spec2_op_table);
                break;
        case bcond_op:
                rt = MIPSInst_RT(inst);
                rs = MIPSInst_RS(inst);
                switch (rt) {
                case tgei_op:
                        if ((long)regs->regs[rs] >= MIPSInst_SIMM(inst))
                                do_trap_or_bp(regs, 0, 0, "TGEI");

                        MIPS_R2_STATS(traps);

                        break;
                case tgeiu_op:
                        if (regs->regs[rs] >= MIPSInst_UIMM(inst))
                                do_trap_or_bp(regs, 0, 0, "TGEIU");

                        MIPS_R2_STATS(traps);

                        break;
                case tlti_op:
                        if ((long)regs->regs[rs] < MIPSInst_SIMM(inst))
                                do_trap_or_bp(regs, 0, 0, "TLTI");

                        MIPS_R2_STATS(traps);

                        break;
                case tltiu_op:
                        if (regs->regs[rs] < MIPSInst_UIMM(inst))
                                do_trap_or_bp(regs, 0, 0, "TLTIU");

                        MIPS_R2_STATS(traps);

                        break;
                case teqi_op:
                        if (regs->regs[rs] == MIPSInst_SIMM(inst))
                                do_trap_or_bp(regs, 0, 0, "TEQI");

                        MIPS_R2_STATS(traps);

                        break;
                case tnei_op:
                        if (regs->regs[rs] != MIPSInst_SIMM(inst))
                                do_trap_or_bp(regs, 0, 0, "TNEI");

                        MIPS_R2_STATS(traps);

                        break;
                case bltzl_op:
                case bgezl_op:
                case bltzall_op:
                case bgezall_op:
                        if (delay_slot(regs)) {
                                err = SIGILL;
                                break;
                        }
                        regs->regs[31] = r31;
                        regs->cp0_epc = epc;
                        err = __compute_return_epc(regs);
                        if (err < 0)
                                return SIGEMT;
                        if (err != BRANCH_LIKELY_TAKEN)
                                break;
                        cpc = regs->cp0_epc;
                        nepc = epc + 4;
                        err = __get_user(nir, (u32 __user *)nepc);
                        if (err) {
                                err = SIGSEGV;
                                break;
                        }
                        /*
                         * This will probably be optimized away when
                         * CONFIG_DEBUG_FS is not enabled
                         */
                        switch (rt) {
                        case bltzl_op:
                                MIPS_R2BR_STATS(bltzl);
                                break;
                        case bgezl_op:
                                MIPS_R2BR_STATS(bgezl);
                                break;
                        case bltzall_op:
                                MIPS_R2BR_STATS(bltzall);
                                break;
                        case bgezall_op:
                                MIPS_R2BR_STATS(bgezall);
                                break;
                        }

                        switch (MIPSInst_OPCODE(nir)) {
                        case cop1_op:
                        case cop1x_op:
                        case lwc1_op:
                        case swc1_op:
                                regs->cp0_cause |= CAUSEF_BD;
                                goto fpu_emul;
                        }
                        if (nir) {
                                err = mipsr6_emul(regs, nir);
                                if (err > 0) {
                                        err = mips_dsemul(regs, nir, epc, cpc);
                                        if (err == SIGILL)
                                                err = SIGEMT;
                                        MIPS_R2_STATS(dsemul);
                                }
                        }
                        break;
                case bltzal_op:
                case bgezal_op:
                        if (delay_slot(regs)) {
                                err = SIGILL;
                                break;
                        }
                        regs->regs[31] = r31;
                        regs->cp0_epc = epc;
                        err = __compute_return_epc(regs);
                        if (err < 0)
                                return SIGEMT;
                        cpc = regs->cp0_epc;
                        nepc = epc + 4;
                        err = __get_user(nir, (u32 __user *)nepc);
                        if (err) {
                                err = SIGSEGV;
                                break;
                        }
                        /*
                         * This will probably be optimized away when
                         * CONFIG_DEBUG_FS is not enabled
                         */
                        switch (rt) {
                        case bltzal_op:
                                MIPS_R2BR_STATS(bltzal);
                                break;
                        case bgezal_op:
                                MIPS_R2BR_STATS(bgezal);
                                break;
                        }

                        switch (MIPSInst_OPCODE(nir)) {
                        case cop1_op:
                        case cop1x_op:
                        case lwc1_op:
                        case swc1_op:
                                regs->cp0_cause |= CAUSEF_BD;
                                goto fpu_emul;
                        }
                        if (nir) {
                                err = mipsr6_emul(regs, nir);
                                if (err > 0) {
                                        err = mips_dsemul(regs, nir, epc, cpc);
                                        if (err == SIGILL)
                                                err = SIGEMT;
                                        MIPS_R2_STATS(dsemul);
                                }
                        }
                        break;
                default:
                        regs->regs[31] = r31;
                        regs->cp0_epc = epc;
                        err = SIGILL;
                        break;
                }
                break;

        case blezl_op:
        case bgtzl_op:
                /*
                 * For BLEZL and BGTZL, rt field must be set to 0. If this
                 * is not the case, this may be an encoding of a MIPS R6
                 * instruction, so return to CPU execution if this occurs
                 */
                if (MIPSInst_RT(inst)) {
                        err = SIGILL;
                        break;
                }
                fallthrough;
        case beql_op:
        case bnel_op:
                if (delay_slot(regs)) {
                        err = SIGILL;
                        break;
                }
                regs->regs[31] = r31;
                regs->cp0_epc = epc;
                err = __compute_return_epc(regs);
                if (err < 0)
                        return SIGEMT;
                if (err != BRANCH_LIKELY_TAKEN)
                        break;
                cpc = regs->cp0_epc;
                nepc = epc + 4;
                err = __get_user(nir, (u32 __user *)nepc);
                if (err) {
                        err = SIGSEGV;
                        break;
                }
                /*
                 * This will probably be optimized away when
                 * CONFIG_DEBUG_FS is not enabled
                 */
                switch (MIPSInst_OPCODE(inst)) {
                case beql_op:
                        MIPS_R2BR_STATS(beql);
                        break;
                case bnel_op:
                        MIPS_R2BR_STATS(bnel);
                        break;
                case blezl_op:
                        MIPS_R2BR_STATS(blezl);
                        break;
                case bgtzl_op:
                        MIPS_R2BR_STATS(bgtzl);
                        break;
                }

                switch (MIPSInst_OPCODE(nir)) {
                case cop1_op:
                case cop1x_op:
                case lwc1_op:
                case swc1_op:
                        regs->cp0_cause |= CAUSEF_BD;
                        goto fpu_emul;
                }
                if (nir) {
                        err = mipsr6_emul(regs, nir);
                        if (err > 0) {
                                err = mips_dsemul(regs, nir, epc, cpc);
                                if (err == SIGILL)
                                        err = SIGEMT;
                                MIPS_R2_STATS(dsemul);
                        }
                }
                break;
        case lwc1_op:
        case swc1_op:
        case cop1_op:
        case cop1x_op:
fpu_emul:
                regs->regs[31] = r31;
                regs->cp0_epc = epc;

                err = fpu_emulator_cop1Handler(regs, &current->thread.fpu, 0,
                                               &fault_addr);

                /*
                 * We can't allow the emulated instruction to leave any
                 * enabled Cause bits set in $fcr31.
                 */
                *fcr31 = res = mask_fcr31_x(current->thread.fpu.fcr31);
                current->thread.fpu.fcr31 &= ~res;

                /*
                 * this is a tricky issue - lose_fpu() uses LL/SC atomics
                 * if FPU is owned and effectively cancels user level LL/SC.
                 * So, it could be logical to don't restore FPU ownership here.
                 * But the sequence of multiple FPU instructions is much much
                 * more often than LL-FPU-SC and I prefer loop here until
                 * next scheduler cycle cancels FPU ownership
                 */
                own_fpu(1);     /* Restore FPU state. */

                if (err)
                        current->thread.cp0_baduaddr = (unsigned long)fault_addr;

                MIPS_R2_STATS(fpus);

                break;

        case lwl_op:
                rt = regs->regs[MIPSInst_RT(inst)];
                vaddr = regs->regs[MIPSInst_RS(inst)] + MIPSInst_SIMM(inst);
                if (!access_ok((void __user *)vaddr, 4)) {
                        current->thread.cp0_baduaddr = vaddr;
                        err = SIGSEGV;
                        break;
                }
                __asm__ __volatile__(
                        "       .set    push\n"
                        "       .set    reorder\n"
#ifdef CONFIG_CPU_LITTLE_ENDIAN
                        "1:"    LB      "%1, 0(%2)\n"
                                INS     "%0, %1, 24, 8\n"
                        "       andi    %1, %2, 0x3\n"
                        "       beq     $0, %1, 9f\n"
                                ADDIU   "%2, %2, -1\n"
                        "2:"    LB      "%1, 0(%2)\n"
                                INS     "%0, %1, 16, 8\n"
                        "       andi    %1, %2, 0x3\n"
                        "       beq     $0, %1, 9f\n"
                                ADDIU   "%2, %2, -1\n"
                        "3:"    LB      "%1, 0(%2)\n"
                                INS     "%0, %1, 8, 8\n"
                        "       andi    %1, %2, 0x3\n"
                        "       beq     $0, %1, 9f\n"
                                ADDIU   "%2, %2, -1\n"
                        "4:"    LB      "%1, 0(%2)\n"
                                INS     "%0, %1, 0, 8\n"
#else /* !CONFIG_CPU_LITTLE_ENDIAN */
                        "1:"    LB      "%1, 0(%2)\n"
                                INS     "%0, %1, 24, 8\n"
                                ADDIU   "%2, %2, 1\n"
                        "       andi    %1, %2, 0x3\n"
                        "       beq     $0, %1, 9f\n"
                        "2:"    LB      "%1, 0(%2)\n"
                                INS     "%0, %1, 16, 8\n"
                                ADDIU   "%2, %2, 1\n"
                        "       andi    %1, %2, 0x3\n"
                        "       beq     $0, %1, 9f\n"
                        "3:"    LB      "%1, 0(%2)\n"
                                INS     "%0, %1, 8, 8\n"
                                ADDIU   "%2, %2, 1\n"
                        "       andi    %1, %2, 0x3\n"
                        "       beq     $0, %1, 9f\n"
                        "4:"    LB      "%1, 0(%2)\n"
                                INS     "%0, %1, 0, 8\n"
#endif /* CONFIG_CPU_LITTLE_ENDIAN */
                        "9:     sll     %0, %0, 0\n"
                        "10:\n"
                        "       .insn\n"
                        "       .section        .fixup,\"ax\"\n"
                        "8:     li      %3,%4\n"
                        "       j       10b\n"
                        "       .previous\n"
                        "       .section        __ex_table,\"a\"\n"
                        STR(PTR_WD) " 1b,8b\n"
                        STR(PTR_WD) " 2b,8b\n"
                        STR(PTR_WD) " 3b,8b\n"
                        STR(PTR_WD) " 4b,8b\n"
                        "       .previous\n"
                        "       .set    pop\n"
                        : "+&r"(rt), "=&r"(rs),
                          "+&r"(vaddr), "+&r"(err)
                        : "i"(SIGSEGV));

                if (MIPSInst_RT(inst) && !err)
                        regs->regs[MIPSInst_RT(inst)] = rt;

                MIPS_R2_STATS(loads);

                break;

        case lwr_op:
                rt = regs->regs[MIPSInst_RT(inst)];
                vaddr = regs->regs[MIPSInst_RS(inst)] + MIPSInst_SIMM(inst);
                if (!access_ok((void __user *)vaddr, 4)) {
                        current->thread.cp0_baduaddr = vaddr;
                        err = SIGSEGV;
                        break;
                }
                __asm__ __volatile__(
                        "       .set    push\n"
                        "       .set    reorder\n"
#ifdef CONFIG_CPU_LITTLE_ENDIAN
                        "1:"    LB      "%1, 0(%2)\n"
                                INS     "%0, %1, 0, 8\n"
                                ADDIU   "%2, %2, 1\n"
                        "       andi    %1, %2, 0x3\n"
                        "       beq     $0, %1, 9f\n"
                        "2:"    LB      "%1, 0(%2)\n"
                                INS     "%0, %1, 8, 8\n"
                                ADDIU   "%2, %2, 1\n"
                        "       andi    %1, %2, 0x3\n"
                        "       beq     $0, %1, 9f\n"
                        "3:"    LB      "%1, 0(%2)\n"
                                INS     "%0, %1, 16, 8\n"
                                ADDIU   "%2, %2, 1\n"
                        "       andi    %1, %2, 0x3\n"
                        "       beq     $0, %1, 9f\n"
                        "4:"    LB      "%1, 0(%2)\n"
                                INS     "%0, %1, 24, 8\n"
                        "       sll     %0, %0, 0\n"
#else /* !CONFIG_CPU_LITTLE_ENDIAN */
                        "1:"    LB      "%1, 0(%2)\n"
                                INS     "%0, %1, 0, 8\n"
                        "       andi    %1, %2, 0x3\n"
                        "       beq     $0, %1, 9f\n"
                                ADDIU   "%2, %2, -1\n"
                        "2:"    LB      "%1, 0(%2)\n"
                                INS     "%0, %1, 8, 8\n"
                        "       andi    %1, %2, 0x3\n"
                        "       beq     $0, %1, 9f\n"
                                ADDIU   "%2, %2, -1\n"
                        "3:"    LB      "%1, 0(%2)\n"
                                INS     "%0, %1, 16, 8\n"
                        "       andi    %1, %2, 0x3\n"
                        "       beq     $0, %1, 9f\n"
                                ADDIU   "%2, %2, -1\n"
                        "4:"    LB      "%1, 0(%2)\n"
                                INS     "%0, %1, 24, 8\n"
                        "       sll     %0, %0, 0\n"
#endif /* CONFIG_CPU_LITTLE_ENDIAN */
                        "9:\n"
                        "10:\n"
                        "       .insn\n"
                        "       .section        .fixup,\"ax\"\n"
                        "8:     li      %3,%4\n"
                        "       j       10b\n"
                        "       .previous\n"
                        "       .section        __ex_table,\"a\"\n"
                        STR(PTR_WD) " 1b,8b\n"
                        STR(PTR_WD) " 2b,8b\n"
                        STR(PTR_WD) " 3b,8b\n"
                        STR(PTR_WD) " 4b,8b\n"
                        "       .previous\n"
                        "       .set    pop\n"
                        : "+&r"(rt), "=&r"(rs),
                          "+&r"(vaddr), "+&r"(err)
                        : "i"(SIGSEGV));
                if (MIPSInst_RT(inst) && !err)
                        regs->regs[MIPSInst_RT(inst)] = rt;

                MIPS_R2_STATS(loads);

                break;

        case swl_op:
                rt = regs->regs[MIPSInst_RT(inst)];
                vaddr = regs->regs[MIPSInst_RS(inst)] + MIPSInst_SIMM(inst);
                if (!access_ok((void __user *)vaddr, 4)) {
                        current->thread.cp0_baduaddr = vaddr;
                        err = SIGSEGV;
                        break;
                }
                __asm__ __volatile__(
                        "       .set    push\n"
                        "       .set    reorder\n"
#ifdef CONFIG_CPU_LITTLE_ENDIAN
                                EXT     "%1, %0, 24, 8\n"
                        "1:"    SB      "%1, 0(%2)\n"
                        "       andi    %1, %2, 0x3\n"
                        "       beq     $0, %1, 9f\n"
                                ADDIU   "%2, %2, -1\n"
                                EXT     "%1, %0, 16, 8\n"
                        "2:"    SB      "%1, 0(%2)\n"
                        "       andi    %1, %2, 0x3\n"
                        "       beq     $0, %1, 9f\n"
                                ADDIU   "%2, %2, -1\n"
                                EXT     "%1, %0, 8, 8\n"
                        "3:"    SB      "%1, 0(%2)\n"
                        "       andi    %1, %2, 0x3\n"
                        "       beq     $0, %1, 9f\n"
                                ADDIU   "%2, %2, -1\n"
                                EXT     "%1, %0, 0, 8\n"
                        "4:"    SB      "%1, 0(%2)\n"
#else /* !CONFIG_CPU_LITTLE_ENDIAN */
                                EXT     "%1, %0, 24, 8\n"
                        "1:"    SB      "%1, 0(%2)\n"
                                ADDIU   "%2, %2, 1\n"
                        "       andi    %1, %2, 0x3\n"
                        "       beq     $0, %1, 9f\n"
                                EXT     "%1, %0, 16, 8\n"
                        "2:"    SB      "%1, 0(%2)\n"
                                ADDIU   "%2, %2, 1\n"
                        "       andi    %1, %2, 0x3\n"
                        "       beq     $0, %1, 9f\n"
                                EXT     "%1, %0, 8, 8\n"
                        "3:"    SB      "%1, 0(%2)\n"
                                ADDIU   "%2, %2, 1\n"
                        "       andi    %1, %2, 0x3\n"
                        "       beq     $0, %1, 9f\n"
                                EXT     "%1, %0, 0, 8\n"
                        "4:"    SB      "%1, 0(%2)\n"
#endif /* CONFIG_CPU_LITTLE_ENDIAN */
                        "9:\n"
                        "       .insn\n"
                        "       .section        .fixup,\"ax\"\n"
                        "8:     li      %3,%4\n"
                        "       j       9b\n"
                        "       .previous\n"
                        "       .section        __ex_table,\"a\"\n"
                        STR(PTR_WD) " 1b,8b\n"
                        STR(PTR_WD) " 2b,8b\n"
                        STR(PTR_WD) " 3b,8b\n"
                        STR(PTR_WD) " 4b,8b\n"
                        "       .previous\n"
                        "       .set    pop\n"
                        : "+&r"(rt), "=&r"(rs),
                          "+&r"(vaddr), "+&r"(err)
                        : "i"(SIGSEGV)
                        : "memory");

                MIPS_R2_STATS(stores);

                break;

        case swr_op:
                rt = regs->regs[MIPSInst_RT(inst)];
                vaddr = regs->regs[MIPSInst_RS(inst)] + MIPSInst_SIMM(inst);
                if (!access_ok((void __user *)vaddr, 4)) {
                        current->thread.cp0_baduaddr = vaddr;
                        err = SIGSEGV;
                        break;
                }
                __asm__ __volatile__(
                        "       .set    push\n"
                        "       .set    reorder\n"
#ifdef CONFIG_CPU_LITTLE_ENDIAN
                                EXT     "%1, %0, 0, 8\n"
                        "1:"    SB      "%1, 0(%2)\n"
                                ADDIU   "%2, %2, 1\n"
                        "       andi    %1, %2, 0x3\n"
                        "       beq     $0, %1, 9f\n"
                                EXT     "%1, %0, 8, 8\n"
                        "2:"    SB      "%1, 0(%2)\n"
                                ADDIU   "%2, %2, 1\n"
                        "       andi    %1, %2, 0x3\n"
                        "       beq     $0, %1, 9f\n"
                                EXT     "%1, %0, 16, 8\n"
                        "3:"    SB      "%1, 0(%2)\n"
                                ADDIU   "%2, %2, 1\n"
                        "       andi    %1, %2, 0x3\n"
                        "       beq     $0, %1, 9f\n"
                                EXT     "%1, %0, 24, 8\n"
                        "4:"    SB      "%1, 0(%2)\n"
#else /* !CONFIG_CPU_LITTLE_ENDIAN */
                                EXT     "%1, %0, 0, 8\n"
                        "1:"    SB      "%1, 0(%2)\n"
                        "       andi    %1, %2, 0x3\n"
                        "       beq     $0, %1, 9f\n"
                                ADDIU   "%2, %2, -1\n"
                                EXT     "%1, %0, 8, 8\n"
                        "2:"    SB      "%1, 0(%2)\n"
                        "       andi    %1, %2, 0x3\n"
                        "       beq     $0, %1, 9f\n"
                                ADDIU   "%2, %2, -1\n"
                                EXT     "%1, %0, 16, 8\n"
                        "3:"    SB      "%1, 0(%2)\n"
                        "       andi    %1, %2, 0x3\n"
                        "       beq     $0, %1, 9f\n"
                                ADDIU   "%2, %2, -1\n"
                                EXT     "%1, %0, 24, 8\n"
                        "4:"    SB      "%1, 0(%2)\n"
#endif /* CONFIG_CPU_LITTLE_ENDIAN */
                        "9:\n"
                        "       .insn\n"
                        "       .section        .fixup,\"ax\"\n"
                        "8:     li      %3,%4\n"
                        "       j       9b\n"
                        "       .previous\n"
                        "       .section        __ex_table,\"a\"\n"
                        STR(PTR_WD) " 1b,8b\n"
                        STR(PTR_WD) " 2b,8b\n"
                        STR(PTR_WD) " 3b,8b\n"
                        STR(PTR_WD) " 4b,8b\n"
                        "       .previous\n"
                        "       .set    pop\n"
                        : "+&r"(rt), "=&r"(rs),
                          "+&r"(vaddr), "+&r"(err)
                        : "i"(SIGSEGV)
                        : "memory");

                MIPS_R2_STATS(stores);

                break;

        case ldl_op:
                if (IS_ENABLED(CONFIG_32BIT)) {
                    err = SIGILL;
                    break;
                }

                rt = regs->regs[MIPSInst_RT(inst)];
                vaddr = regs->regs[MIPSInst_RS(inst)] + MIPSInst_SIMM(inst);
                if (!access_ok((void __user *)vaddr, 8)) {
                        current->thread.cp0_baduaddr = vaddr;
                        err = SIGSEGV;
                        break;
                }
                __asm__ __volatile__(
                        "       .set    push\n"
                        "       .set    reorder\n"
#ifdef CONFIG_CPU_LITTLE_ENDIAN
                        "1:     lb      %1, 0(%2)\n"
                        "       dinsu   %0, %1, 56, 8\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "       daddiu  %2, %2, -1\n"
                        "2:     lb      %1, 0(%2)\n"
                        "       dinsu   %0, %1, 48, 8\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "       daddiu  %2, %2, -1\n"
                        "3:     lb      %1, 0(%2)\n"
                        "       dinsu   %0, %1, 40, 8\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "       daddiu  %2, %2, -1\n"
                        "4:     lb      %1, 0(%2)\n"
                        "       dinsu   %0, %1, 32, 8\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "       daddiu  %2, %2, -1\n"
                        "5:     lb      %1, 0(%2)\n"
                        "       dins    %0, %1, 24, 8\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "       daddiu  %2, %2, -1\n"
                        "6:     lb      %1, 0(%2)\n"
                        "       dins    %0, %1, 16, 8\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "       daddiu  %2, %2, -1\n"
                        "7:     lb      %1, 0(%2)\n"
                        "       dins    %0, %1, 8, 8\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "       daddiu  %2, %2, -1\n"
                        "0:     lb      %1, 0(%2)\n"
                        "       dins    %0, %1, 0, 8\n"
#else /* !CONFIG_CPU_LITTLE_ENDIAN */
                        "1:     lb      %1, 0(%2)\n"
                        "       dinsu   %0, %1, 56, 8\n"
                        "       daddiu  %2, %2, 1\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "2:     lb      %1, 0(%2)\n"
                        "       dinsu   %0, %1, 48, 8\n"
                        "       daddiu  %2, %2, 1\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "3:     lb      %1, 0(%2)\n"
                        "       dinsu   %0, %1, 40, 8\n"
                        "       daddiu  %2, %2, 1\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "4:     lb      %1, 0(%2)\n"
                        "       dinsu   %0, %1, 32, 8\n"
                        "       daddiu  %2, %2, 1\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "5:     lb      %1, 0(%2)\n"
                        "       dins    %0, %1, 24, 8\n"
                        "       daddiu  %2, %2, 1\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "6:     lb      %1, 0(%2)\n"
                        "       dins    %0, %1, 16, 8\n"
                        "       daddiu  %2, %2, 1\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "7:     lb      %1, 0(%2)\n"
                        "       dins    %0, %1, 8, 8\n"
                        "       daddiu  %2, %2, 1\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "0:     lb      %1, 0(%2)\n"
                        "       dins    %0, %1, 0, 8\n"
#endif /* CONFIG_CPU_LITTLE_ENDIAN */
                        "9:\n"
                        "       .insn\n"
                        "       .section        .fixup,\"ax\"\n"
                        "8:     li      %3,%4\n"
                        "       j       9b\n"
                        "       .previous\n"
                        "       .section        __ex_table,\"a\"\n"
                        STR(PTR_WD) " 1b,8b\n"
                        STR(PTR_WD) " 2b,8b\n"
                        STR(PTR_WD) " 3b,8b\n"
                        STR(PTR_WD) " 4b,8b\n"
                        STR(PTR_WD) " 5b,8b\n"
                        STR(PTR_WD) " 6b,8b\n"
                        STR(PTR_WD) " 7b,8b\n"
                        STR(PTR_WD) " 0b,8b\n"
                        "       .previous\n"
                        "       .set    pop\n"
                        : "+&r"(rt), "=&r"(rs),
                          "+&r"(vaddr), "+&r"(err)
                        : "i"(SIGSEGV));
                if (MIPSInst_RT(inst) && !err)
                        regs->regs[MIPSInst_RT(inst)] = rt;

                MIPS_R2_STATS(loads);
                break;

        case ldr_op:
                if (IS_ENABLED(CONFIG_32BIT)) {
                    err = SIGILL;
                    break;
                }

                rt = regs->regs[MIPSInst_RT(inst)];
                vaddr = regs->regs[MIPSInst_RS(inst)] + MIPSInst_SIMM(inst);
                if (!access_ok((void __user *)vaddr, 8)) {
                        current->thread.cp0_baduaddr = vaddr;
                        err = SIGSEGV;
                        break;
                }
                __asm__ __volatile__(
                        "       .set    push\n"
                        "       .set    reorder\n"
#ifdef CONFIG_CPU_LITTLE_ENDIAN
                        "1:     lb      %1, 0(%2)\n"
                        "       dins   %0, %1, 0, 8\n"
                        "       daddiu  %2, %2, 1\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "2:     lb      %1, 0(%2)\n"
                        "       dins   %0, %1, 8, 8\n"
                        "       daddiu  %2, %2, 1\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "3:     lb      %1, 0(%2)\n"
                        "       dins   %0, %1, 16, 8\n"
                        "       daddiu  %2, %2, 1\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "4:     lb      %1, 0(%2)\n"
                        "       dins   %0, %1, 24, 8\n"
                        "       daddiu  %2, %2, 1\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "5:     lb      %1, 0(%2)\n"
                        "       dinsu    %0, %1, 32, 8\n"
                        "       daddiu  %2, %2, 1\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "6:     lb      %1, 0(%2)\n"
                        "       dinsu    %0, %1, 40, 8\n"
                        "       daddiu  %2, %2, 1\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "7:     lb      %1, 0(%2)\n"
                        "       dinsu    %0, %1, 48, 8\n"
                        "       daddiu  %2, %2, 1\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "0:     lb      %1, 0(%2)\n"
                        "       dinsu    %0, %1, 56, 8\n"
#else /* !CONFIG_CPU_LITTLE_ENDIAN */
                        "1:     lb      %1, 0(%2)\n"
                        "       dins   %0, %1, 0, 8\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "       daddiu  %2, %2, -1\n"
                        "2:     lb      %1, 0(%2)\n"
                        "       dins   %0, %1, 8, 8\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "       daddiu  %2, %2, -1\n"
                        "3:     lb      %1, 0(%2)\n"
                        "       dins   %0, %1, 16, 8\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "       daddiu  %2, %2, -1\n"
                        "4:     lb      %1, 0(%2)\n"
                        "       dins   %0, %1, 24, 8\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "       daddiu  %2, %2, -1\n"
                        "5:     lb      %1, 0(%2)\n"
                        "       dinsu    %0, %1, 32, 8\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "       daddiu  %2, %2, -1\n"
                        "6:     lb      %1, 0(%2)\n"
                        "       dinsu    %0, %1, 40, 8\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "       daddiu  %2, %2, -1\n"
                        "7:     lb      %1, 0(%2)\n"
                        "       dinsu    %0, %1, 48, 8\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "       daddiu  %2, %2, -1\n"
                        "0:     lb      %1, 0(%2)\n"
                        "       dinsu    %0, %1, 56, 8\n"
#endif /* CONFIG_CPU_LITTLE_ENDIAN */
                        "9:\n"
                        "       .insn\n"
                        "       .section        .fixup,\"ax\"\n"
                        "8:     li     %3,%4\n"
                        "       j      9b\n"
                        "       .previous\n"
                        "       .section        __ex_table,\"a\"\n"
                        STR(PTR_WD) " 1b,8b\n"
                        STR(PTR_WD) " 2b,8b\n"
                        STR(PTR_WD) " 3b,8b\n"
                        STR(PTR_WD) " 4b,8b\n"
                        STR(PTR_WD) " 5b,8b\n"
                        STR(PTR_WD) " 6b,8b\n"
                        STR(PTR_WD) " 7b,8b\n"
                        STR(PTR_WD) " 0b,8b\n"
                        "       .previous\n"
                        "       .set    pop\n"
                        : "+&r"(rt), "=&r"(rs),
                          "+&r"(vaddr), "+&r"(err)
                        : "i"(SIGSEGV));
                if (MIPSInst_RT(inst) && !err)
                        regs->regs[MIPSInst_RT(inst)] = rt;

                MIPS_R2_STATS(loads);
                break;

        case sdl_op:
                if (IS_ENABLED(CONFIG_32BIT)) {
                    err = SIGILL;
                    break;
                }

                rt = regs->regs[MIPSInst_RT(inst)];
                vaddr = regs->regs[MIPSInst_RS(inst)] + MIPSInst_SIMM(inst);
                if (!access_ok((void __user *)vaddr, 8)) {
                        current->thread.cp0_baduaddr = vaddr;
                        err = SIGSEGV;
                        break;
                }
                __asm__ __volatile__(
                        "       .set    push\n"
                        "       .set    reorder\n"
#ifdef CONFIG_CPU_LITTLE_ENDIAN
                        "       dextu   %1, %0, 56, 8\n"
                        "1:     sb      %1, 0(%2)\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "       daddiu  %2, %2, -1\n"
                        "       dextu   %1, %0, 48, 8\n"
                        "2:     sb      %1, 0(%2)\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "       daddiu  %2, %2, -1\n"
                        "       dextu   %1, %0, 40, 8\n"
                        "3:     sb      %1, 0(%2)\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "       daddiu  %2, %2, -1\n"
                        "       dextu   %1, %0, 32, 8\n"
                        "4:     sb      %1, 0(%2)\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "       daddiu  %2, %2, -1\n"
                        "       dext    %1, %0, 24, 8\n"
                        "5:     sb      %1, 0(%2)\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "       daddiu  %2, %2, -1\n"
                        "       dext    %1, %0, 16, 8\n"
                        "6:     sb      %1, 0(%2)\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "       daddiu  %2, %2, -1\n"
                        "       dext    %1, %0, 8, 8\n"
                        "7:     sb      %1, 0(%2)\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "       daddiu  %2, %2, -1\n"
                        "       dext    %1, %0, 0, 8\n"
                        "0:     sb      %1, 0(%2)\n"
#else /* !CONFIG_CPU_LITTLE_ENDIAN */
                        "       dextu   %1, %0, 56, 8\n"
                        "1:     sb      %1, 0(%2)\n"
                        "       daddiu  %2, %2, 1\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "       dextu   %1, %0, 48, 8\n"
                        "2:     sb      %1, 0(%2)\n"
                        "       daddiu  %2, %2, 1\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "       dextu   %1, %0, 40, 8\n"
                        "3:     sb      %1, 0(%2)\n"
                        "       daddiu  %2, %2, 1\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "       dextu   %1, %0, 32, 8\n"
                        "4:     sb      %1, 0(%2)\n"
                        "       daddiu  %2, %2, 1\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "       dext    %1, %0, 24, 8\n"
                        "5:     sb      %1, 0(%2)\n"
                        "       daddiu  %2, %2, 1\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "       dext    %1, %0, 16, 8\n"
                        "6:     sb      %1, 0(%2)\n"
                        "       daddiu  %2, %2, 1\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "       dext    %1, %0, 8, 8\n"
                        "7:     sb      %1, 0(%2)\n"
                        "       daddiu  %2, %2, 1\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "       dext    %1, %0, 0, 8\n"
                        "0:     sb      %1, 0(%2)\n"
#endif /* CONFIG_CPU_LITTLE_ENDIAN */
                        "9:\n"
                        "       .insn\n"
                        "       .section        .fixup,\"ax\"\n"
                        "8:     li      %3,%4\n"
                        "       j       9b\n"
                        "       .previous\n"
                        "       .section        __ex_table,\"a\"\n"
                        STR(PTR_WD) " 1b,8b\n"
                        STR(PTR_WD) " 2b,8b\n"
                        STR(PTR_WD) " 3b,8b\n"
                        STR(PTR_WD) " 4b,8b\n"
                        STR(PTR_WD) " 5b,8b\n"
                        STR(PTR_WD) " 6b,8b\n"
                        STR(PTR_WD) " 7b,8b\n"
                        STR(PTR_WD) " 0b,8b\n"
                        "       .previous\n"
                        "       .set    pop\n"
                        : "+&r"(rt), "=&r"(rs),
                          "+&r"(vaddr), "+&r"(err)
                        : "i"(SIGSEGV)
                        : "memory");

                MIPS_R2_STATS(stores);
                break;

        case sdr_op:
                if (IS_ENABLED(CONFIG_32BIT)) {
                    err = SIGILL;
                    break;
                }

                rt = regs->regs[MIPSInst_RT(inst)];
                vaddr = regs->regs[MIPSInst_RS(inst)] + MIPSInst_SIMM(inst);
                if (!access_ok((void __user *)vaddr, 8)) {
                        current->thread.cp0_baduaddr = vaddr;
                        err = SIGSEGV;
                        break;
                }
                __asm__ __volatile__(
                        "       .set    push\n"
                        "       .set    reorder\n"
#ifdef CONFIG_CPU_LITTLE_ENDIAN
                        "       dext    %1, %0, 0, 8\n"
                        "1:     sb      %1, 0(%2)\n"
                        "       daddiu  %2, %2, 1\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "       dext    %1, %0, 8, 8\n"
                        "2:     sb      %1, 0(%2)\n"
                        "       daddiu  %2, %2, 1\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "       dext    %1, %0, 16, 8\n"
                        "3:     sb      %1, 0(%2)\n"
                        "       daddiu  %2, %2, 1\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "       dext    %1, %0, 24, 8\n"
                        "4:     sb      %1, 0(%2)\n"
                        "       daddiu  %2, %2, 1\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "       dextu   %1, %0, 32, 8\n"
                        "5:     sb      %1, 0(%2)\n"
                        "       daddiu  %2, %2, 1\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "       dextu   %1, %0, 40, 8\n"
                        "6:     sb      %1, 0(%2)\n"
                        "       daddiu  %2, %2, 1\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "       dextu   %1, %0, 48, 8\n"
                        "7:     sb      %1, 0(%2)\n"
                        "       daddiu  %2, %2, 1\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "       dextu   %1, %0, 56, 8\n"
                        "0:     sb      %1, 0(%2)\n"
#else /* !CONFIG_CPU_LITTLE_ENDIAN */
                        "       dext    %1, %0, 0, 8\n"
                        "1:     sb      %1, 0(%2)\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "       daddiu  %2, %2, -1\n"
                        "       dext    %1, %0, 8, 8\n"
                        "2:     sb      %1, 0(%2)\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "       daddiu  %2, %2, -1\n"
                        "       dext    %1, %0, 16, 8\n"
                        "3:     sb      %1, 0(%2)\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "       daddiu  %2, %2, -1\n"
                        "       dext    %1, %0, 24, 8\n"
                        "4:     sb      %1, 0(%2)\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "       daddiu  %2, %2, -1\n"
                        "       dextu   %1, %0, 32, 8\n"
                        "5:     sb      %1, 0(%2)\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "       daddiu  %2, %2, -1\n"
                        "       dextu   %1, %0, 40, 8\n"
                        "6:     sb      %1, 0(%2)\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "       daddiu  %2, %2, -1\n"
                        "       dextu   %1, %0, 48, 8\n"
                        "7:     sb      %1, 0(%2)\n"
                        "       andi    %1, %2, 0x7\n"
                        "       beq     $0, %1, 9f\n"
                        "       daddiu  %2, %2, -1\n"
                        "       dextu   %1, %0, 56, 8\n"
                        "0:     sb      %1, 0(%2)\n"
#endif /* CONFIG_CPU_LITTLE_ENDIAN */
                        "9:\n"
                        "       .insn\n"
                        "       .section        .fixup,\"ax\"\n"
                        "8:     li      %3,%4\n"
                        "       j       9b\n"
                        "       .previous\n"
                        "       .section        __ex_table,\"a\"\n"
                        STR(PTR_WD) " 1b,8b\n"
                        STR(PTR_WD) " 2b,8b\n"
                        STR(PTR_WD) " 3b,8b\n"
                        STR(PTR_WD) " 4b,8b\n"
                        STR(PTR_WD) " 5b,8b\n"
                        STR(PTR_WD) " 6b,8b\n"
                        STR(PTR_WD) " 7b,8b\n"
                        STR(PTR_WD) " 0b,8b\n"
                        "       .previous\n"
                        "       .set    pop\n"
                        : "+&r"(rt), "=&r"(rs),
                          "+&r"(vaddr), "+&r"(err)
                        : "i"(SIGSEGV)
                        : "memory");

                MIPS_R2_STATS(stores);

                break;
        case ll_op:
                vaddr = regs->regs[MIPSInst_RS(inst)] + MIPSInst_SIMM(inst);
                if (vaddr & 0x3) {
                        current->thread.cp0_baduaddr = vaddr;
                        err = SIGBUS;
                        break;
                }
                if (!access_ok((void __user *)vaddr, 4)) {
                        current->thread.cp0_baduaddr = vaddr;
                        err = SIGBUS;
                        break;
                }

                if (!cpu_has_rw_llb) {
                        /*
                         * An LL/SC block can't be safely emulated without
                         * a Config5/LLB availability. So it's probably time to
                         * kill our process before things get any worse. This is
                         * because Config5/LLB allows us to use ERETNC so that
                         * the LLAddr/LLB bit is not cleared when we return from
                         * an exception. MIPS R2 LL/SC instructions trap with an
                         * RI exception so once we emulate them here, we return
                         * back to userland with ERETNC. That preserves the
                         * LLAddr/LLB so the subsequent SC instruction will
                         * succeed preserving the atomic semantics of the LL/SC
                         * block. Without that, there is no safe way to emulate
                         * an LL/SC block in MIPSR2 userland.
                         */
                        pr_err("Can't emulate MIPSR2 LL/SC without Config5/LLB\n");
                        err = SIGKILL;
                        break;
                }

                __asm__ __volatile__(
                        "1:\n"
                        "ll     %0, 0(%2)\n"
                        "2:\n"
                        ".insn\n"
                        ".section        .fixup,\"ax\"\n"
                        "3:\n"
                        "li     %1, %3\n"
                        "j      2b\n"
                        ".previous\n"
                        ".section        __ex_table,\"a\"\n"
                        STR(PTR_WD) " 1b,3b\n"
                        ".previous\n"
                        : "=&r"(res), "+&r"(err)
                        : "r"(vaddr), "i"(SIGSEGV)
                        : "memory");

                if (MIPSInst_RT(inst) && !err)
                        regs->regs[MIPSInst_RT(inst)] = res;
                MIPS_R2_STATS(llsc);

                break;

        case sc_op:
                vaddr = regs->regs[MIPSInst_RS(inst)] + MIPSInst_SIMM(inst);
                if (vaddr & 0x3) {
                        current->thread.cp0_baduaddr = vaddr;
                        err = SIGBUS;
                        break;
                }
                if (!access_ok((void __user *)vaddr, 4)) {
                        current->thread.cp0_baduaddr = vaddr;
                        err = SIGBUS;
                        break;
                }

                if (!cpu_has_rw_llb) {
                        /*
                         * An LL/SC block can't be safely emulated without
                         * a Config5/LLB availability. So it's probably time to
                         * kill our process before things get any worse. This is
                         * because Config5/LLB allows us to use ERETNC so that
                         * the LLAddr/LLB bit is not cleared when we return from
                         * an exception. MIPS R2 LL/SC instructions trap with an
                         * RI exception so once we emulate them here, we return
                         * back to userland with ERETNC. That preserves the
                         * LLAddr/LLB so the subsequent SC instruction will
                         * succeed preserving the atomic semantics of the LL/SC
                         * block. Without that, there is no safe way to emulate
                         * an LL/SC block in MIPSR2 userland.
                         */
                        pr_err("Can't emulate MIPSR2 LL/SC without Config5/LLB\n");
                        err = SIGKILL;
                        break;
                }

                res = regs->regs[MIPSInst_RT(inst)];

                __asm__ __volatile__(
                        "1:\n"
                        "sc     %0, 0(%2)\n"
                        "2:\n"
                        ".insn\n"
                        ".section        .fixup,\"ax\"\n"
                        "3:\n"
                        "li     %1, %3\n"
                        "j      2b\n"
                        ".previous\n"
                        ".section        __ex_table,\"a\"\n"
                        STR(PTR_WD) " 1b,3b\n"
                        ".previous\n"
                        : "+&r"(res), "+&r"(err)
                        : "r"(vaddr), "i"(SIGSEGV));

                if (MIPSInst_RT(inst) && !err)
                        regs->regs[MIPSInst_RT(inst)] = res;

                MIPS_R2_STATS(llsc);

                break;

        case lld_op:
                if (IS_ENABLED(CONFIG_32BIT)) {
                    err = SIGILL;
                    break;
                }

                vaddr = regs->regs[MIPSInst_RS(inst)] + MIPSInst_SIMM(inst);
                if (vaddr & 0x7) {
                        current->thread.cp0_baduaddr = vaddr;
                        err = SIGBUS;
                        break;
                }
                if (!access_ok((void __user *)vaddr, 8)) {
                        current->thread.cp0_baduaddr = vaddr;
                        err = SIGBUS;
                        break;
                }

                if (!cpu_has_rw_llb) {
                        /*
                         * An LL/SC block can't be safely emulated without
                         * a Config5/LLB availability. So it's probably time to
                         * kill our process before things get any worse. This is
                         * because Config5/LLB allows us to use ERETNC so that
                         * the LLAddr/LLB bit is not cleared when we return from
                         * an exception. MIPS R2 LL/SC instructions trap with an
                         * RI exception so once we emulate them here, we return
                         * back to userland with ERETNC. That preserves the
                         * LLAddr/LLB so the subsequent SC instruction will
                         * succeed preserving the atomic semantics of the LL/SC
                         * block. Without that, there is no safe way to emulate
                         * an LL/SC block in MIPSR2 userland.
                         */
                        pr_err("Can't emulate MIPSR2 LL/SC without Config5/LLB\n");
                        err = SIGKILL;
                        break;
                }

                __asm__ __volatile__(
                        "1:\n"
                        "lld    %0, 0(%2)\n"
                        "2:\n"
                        ".insn\n"
                        ".section        .fixup,\"ax\"\n"
                        "3:\n"
                        "li     %1, %3\n"
                        "j      2b\n"
                        ".previous\n"
                        ".section        __ex_table,\"a\"\n"
                        STR(PTR_WD) " 1b,3b\n"
                        ".previous\n"
                        : "=&r"(res), "+&r"(err)
                        : "r"(vaddr), "i"(SIGSEGV)
                        : "memory");
                if (MIPSInst_RT(inst) && !err)
                        regs->regs[MIPSInst_RT(inst)] = res;

                MIPS_R2_STATS(llsc);

                break;

        case scd_op:
                if (IS_ENABLED(CONFIG_32BIT)) {
                    err = SIGILL;
                    break;
                }

                vaddr = regs->regs[MIPSInst_RS(inst)] + MIPSInst_SIMM(inst);
                if (vaddr & 0x7) {
                        current->thread.cp0_baduaddr = vaddr;
                        err = SIGBUS;
                        break;
                }
                if (!access_ok((void __user *)vaddr, 8)) {
                        current->thread.cp0_baduaddr = vaddr;
                        err = SIGBUS;
                        break;
                }

                if (!cpu_has_rw_llb) {
                        /*
                         * An LL/SC block can't be safely emulated without
                         * a Config5/LLB availability. So it's probably time to
                         * kill our process before things get any worse. This is
                         * because Config5/LLB allows us to use ERETNC so that
                         * the LLAddr/LLB bit is not cleared when we return from
                         * an exception. MIPS R2 LL/SC instructions trap with an
                         * RI exception so once we emulate them here, we return
                         * back to userland with ERETNC. That preserves the
                         * LLAddr/LLB so the subsequent SC instruction will
                         * succeed preserving the atomic semantics of the LL/SC
                         * block. Without that, there is no safe way to emulate
                         * an LL/SC block in MIPSR2 userland.
                         */
                        pr_err("Can't emulate MIPSR2 LL/SC without Config5/LLB\n");
                        err = SIGKILL;
                        break;
                }

                res = regs->regs[MIPSInst_RT(inst)];

                __asm__ __volatile__(
                        "1:\n"
                        "scd    %0, 0(%2)\n"
                        "2:\n"
                        ".insn\n"
                        ".section        .fixup,\"ax\"\n"
                        "3:\n"
                        "li     %1, %3\n"
                        "j      2b\n"
                        ".previous\n"
                        ".section        __ex_table,\"a\"\n"
                        STR(PTR_WD) " 1b,3b\n"
                        ".previous\n"
                        : "+&r"(res), "+&r"(err)
                        : "r"(vaddr), "i"(SIGSEGV));

                if (MIPSInst_RT(inst) && !err)
                        regs->regs[MIPSInst_RT(inst)] = res;

                MIPS_R2_STATS(llsc);

                break;
        case pref_op:
                /* skip it */
                break;
        default:
                err = SIGILL;
        }

        /*
         * Let's not return to userland just yet. It's costly and
         * it's likely we have more R2 instructions to emulate
         */
        if (!err && (pass++ < MIPS_R2_EMUL_TOTAL_PASS)) {
                regs->cp0_cause &= ~CAUSEF_BD;
                err = get_user(inst, (u32 __user *)regs->cp0_epc);
                if (!err)
                        goto repeat;

                if (err < 0)
                        err = SIGSEGV;
        }

        if (err && (err != SIGEMT)) {
                regs->regs[31] = r31;
                regs->cp0_epc = epc;
        }

        /* Likely a MIPS R6 compatible instruction */
        if (pass && (err == SIGILL))
                err = 0;

        return err;
}

#ifdef CONFIG_DEBUG_FS

static int mipsr2_emul_show(struct seq_file *s, void *unused)
{

        seq_printf(s, "Instruction\tTotal\tBDslot\n------------------------------\n");
        seq_printf(s, "movs\t\t%ld\t%ld\n",
                   (unsigned long)__this_cpu_read(mipsr2emustats.movs),
                   (unsigned long)__this_cpu_read(mipsr2bdemustats.movs));
        seq_printf(s, "hilo\t\t%ld\t%ld\n",
                   (unsigned long)__this_cpu_read(mipsr2emustats.hilo),
                   (unsigned long)__this_cpu_read(mipsr2bdemustats.hilo));
        seq_printf(s, "muls\t\t%ld\t%ld\n",
                   (unsigned long)__this_cpu_read(mipsr2emustats.muls),
                   (unsigned long)__this_cpu_read(mipsr2bdemustats.muls));
        seq_printf(s, "divs\t\t%ld\t%ld\n",
                   (unsigned long)__this_cpu_read(mipsr2emustats.divs),
                   (unsigned long)__this_cpu_read(mipsr2bdemustats.divs));
        seq_printf(s, "dsps\t\t%ld\t%ld\n",
                   (unsigned long)__this_cpu_read(mipsr2emustats.dsps),
                   (unsigned long)__this_cpu_read(mipsr2bdemustats.dsps));
        seq_printf(s, "bops\t\t%ld\t%ld\n",
                   (unsigned long)__this_cpu_read(mipsr2emustats.bops),
                   (unsigned long)__this_cpu_read(mipsr2bdemustats.bops));
        seq_printf(s, "traps\t\t%ld\t%ld\n",
                   (unsigned long)__this_cpu_read(mipsr2emustats.traps),
                   (unsigned long)__this_cpu_read(mipsr2bdemustats.traps));
        seq_printf(s, "fpus\t\t%ld\t%ld\n",
                   (unsigned long)__this_cpu_read(mipsr2emustats.fpus),
                   (unsigned long)__this_cpu_read(mipsr2bdemustats.fpus));
        seq_printf(s, "loads\t\t%ld\t%ld\n",
                   (unsigned long)__this_cpu_read(mipsr2emustats.loads),
                   (unsigned long)__this_cpu_read(mipsr2bdemustats.loads));
        seq_printf(s, "stores\t\t%ld\t%ld\n",
                   (unsigned long)__this_cpu_read(mipsr2emustats.stores),
                   (unsigned long)__this_cpu_read(mipsr2bdemustats.stores));
        seq_printf(s, "llsc\t\t%ld\t%ld\n",
                   (unsigned long)__this_cpu_read(mipsr2emustats.llsc),
                   (unsigned long)__this_cpu_read(mipsr2bdemustats.llsc));
        seq_printf(s, "dsemul\t\t%ld\t%ld\n",
                   (unsigned long)__this_cpu_read(mipsr2emustats.dsemul),
                   (unsigned long)__this_cpu_read(mipsr2bdemustats.dsemul));
        seq_printf(s, "jr\t\t%ld\n",
                   (unsigned long)__this_cpu_read(mipsr2bremustats.jrs));
        seq_printf(s, "bltzl\t\t%ld\n",
                   (unsigned long)__this_cpu_read(mipsr2bremustats.bltzl));
        seq_printf(s, "bgezl\t\t%ld\n",
                   (unsigned long)__this_cpu_read(mipsr2bremustats.bgezl));
        seq_printf(s, "bltzll\t\t%ld\n",
                   (unsigned long)__this_cpu_read(mipsr2bremustats.bltzll));
        seq_printf(s, "bgezll\t\t%ld\n",
                   (unsigned long)__this_cpu_read(mipsr2bremustats.bgezll));
        seq_printf(s, "bltzal\t\t%ld\n",
                   (unsigned long)__this_cpu_read(mipsr2bremustats.bltzal));
        seq_printf(s, "bgezal\t\t%ld\n",
                   (unsigned long)__this_cpu_read(mipsr2bremustats.bgezal));
        seq_printf(s, "beql\t\t%ld\n",
                   (unsigned long)__this_cpu_read(mipsr2bremustats.beql));
        seq_printf(s, "bnel\t\t%ld\n",
                   (unsigned long)__this_cpu_read(mipsr2bremustats.bnel));
        seq_printf(s, "blezl\t\t%ld\n",
                   (unsigned long)__this_cpu_read(mipsr2bremustats.blezl));
        seq_printf(s, "bgtzl\t\t%ld\n",
                   (unsigned long)__this_cpu_read(mipsr2bremustats.bgtzl));

        return 0;
}

static int mipsr2_clear_show(struct seq_file *s, void *unused)
{
        mipsr2_emul_show(s, unused);

        __this_cpu_write((mipsr2emustats).movs, 0);
        __this_cpu_write((mipsr2bdemustats).movs, 0);
        __this_cpu_write((mipsr2emustats).hilo, 0);
        __this_cpu_write((mipsr2bdemustats).hilo, 0);
        __this_cpu_write((mipsr2emustats).muls, 0);
        __this_cpu_write((mipsr2bdemustats).muls, 0);
        __this_cpu_write((mipsr2emustats).divs, 0);
        __this_cpu_write((mipsr2bdemustats).divs, 0);
        __this_cpu_write((mipsr2emustats).dsps, 0);
        __this_cpu_write((mipsr2bdemustats).dsps, 0);
        __this_cpu_write((mipsr2emustats).bops, 0);
        __this_cpu_write((mipsr2bdemustats).bops, 0);
        __this_cpu_write((mipsr2emustats).traps, 0);
        __this_cpu_write((mipsr2bdemustats).traps, 0);
        __this_cpu_write((mipsr2emustats).fpus, 0);
        __this_cpu_write((mipsr2bdemustats).fpus, 0);
        __this_cpu_write((mipsr2emustats).loads, 0);
        __this_cpu_write((mipsr2bdemustats).loads, 0);
        __this_cpu_write((mipsr2emustats).stores, 0);
        __this_cpu_write((mipsr2bdemustats).stores, 0);
        __this_cpu_write((mipsr2emustats).llsc, 0);
        __this_cpu_write((mipsr2bdemustats).llsc, 0);
        __this_cpu_write((mipsr2emustats).dsemul, 0);
        __this_cpu_write((mipsr2bdemustats).dsemul, 0);
        __this_cpu_write((mipsr2bremustats).jrs, 0);
        __this_cpu_write((mipsr2bremustats).bltzl, 0);
        __this_cpu_write((mipsr2bremustats).bgezl, 0);
        __this_cpu_write((mipsr2bremustats).bltzll, 0);
        __this_cpu_write((mipsr2bremustats).bgezll, 0);
        __this_cpu_write((mipsr2bremustats).bltzall, 0);
        __this_cpu_write((mipsr2bremustats).bgezall, 0);
        __this_cpu_write((mipsr2bremustats).bltzal, 0);
        __this_cpu_write((mipsr2bremustats).bgezal, 0);
        __this_cpu_write((mipsr2bremustats).beql, 0);
        __this_cpu_write((mipsr2bremustats).bnel, 0);
        __this_cpu_write((mipsr2bremustats).blezl, 0);
        __this_cpu_write((mipsr2bremustats).bgtzl, 0);

        return 0;
}

DEFINE_SHOW_ATTRIBUTE(mipsr2_emul);
DEFINE_SHOW_ATTRIBUTE(mipsr2_clear);

static int __init mipsr2_init_debugfs(void)
{
        debugfs_create_file("r2_emul_stats", S_IRUGO, mips_debugfs_dir, NULL,
                            &mipsr2_emul_fops);
        debugfs_create_file("r2_emul_stats_clear", S_IRUGO, mips_debugfs_dir,
                            NULL, &mipsr2_clear_fops);
        return 0;
}

device_initcall(mipsr2_init_debugfs);

#endif /* CONFIG_DEBUG_FS */