[MIPS] 16K & 64K page size fixes

[linux-2.6] / arch / mips / mm / tlbex.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.
 *
 * Synthesize TLB refill handlers at runtime.
 *
 * Copyright (C) 2004,2005,2006 by Thiemo Seufer
 * Copyright (C) 2005  Maciej W. Rozycki
 * Copyright (C) 2006  Ralf Baechle (ralf@linux-mips.org)
 *
 * ... and the days got worse and worse and now you see
 * I've gone completly out of my mind.
 *
 * They're coming to take me a away haha
 * they're coming to take me a away hoho hihi haha
 * to the funny farm where code is beautiful all the time ...
 *
 * (Condolences to Napoleon XIV)
 */

#include <stdarg.h>

#include <linux/mm.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/init.h>

#include <asm/pgtable.h>
#include <asm/cacheflush.h>
#include <asm/mmu_context.h>
#include <asm/inst.h>
#include <asm/elf.h>
#include <asm/smp.h>
#include <asm/war.h>

static __init int __attribute__((unused)) r45k_bvahwbug(void)
{
        /* XXX: We should probe for the presence of this bug, but we don't. */
        return 0;
}

static __init int __attribute__((unused)) r4k_250MHZhwbug(void)
{
        /* XXX: We should probe for the presence of this bug, but we don't. */
        return 0;
}

static __init int __attribute__((unused)) bcm1250_m3_war(void)
{
        return BCM1250_M3_WAR;
}

static __init int __attribute__((unused)) r10000_llsc_war(void)
{
        return R10000_LLSC_WAR;
}

/*
 * A little micro-assembler, intended for TLB refill handler
 * synthesizing. It is intentionally kept simple, does only support
 * a subset of instructions, and does not try to hide pipeline effects
 * like branch delay slots.
 */

enum fields
{
        RS = 0x001,
        RT = 0x002,
        RD = 0x004,
        RE = 0x008,
        SIMM = 0x010,
        UIMM = 0x020,
        BIMM = 0x040,
        JIMM = 0x080,
        FUNC = 0x100,
        SET = 0x200
};

#define OP_MASK         0x2f
#define OP_SH           26
#define RS_MASK         0x1f
#define RS_SH           21
#define RT_MASK         0x1f
#define RT_SH           16
#define RD_MASK         0x1f
#define RD_SH           11
#define RE_MASK         0x1f
#define RE_SH           6
#define IMM_MASK        0xffff
#define IMM_SH          0
#define JIMM_MASK       0x3ffffff
#define JIMM_SH         0
#define FUNC_MASK       0x2f
#define FUNC_SH         0
#define SET_MASK        0x7
#define SET_SH          0

enum opcode {
        insn_invalid,
        insn_addu, insn_addiu, insn_and, insn_andi, insn_beq,
        insn_beql, insn_bgez, insn_bgezl, insn_bltz, insn_bltzl,
        insn_bne, insn_daddu, insn_daddiu, insn_dmfc0, insn_dmtc0,
        insn_dsll, insn_dsll32, insn_dsra, insn_dsrl, insn_dsrl32,
        insn_dsubu, insn_eret, insn_j, insn_jal, insn_jr, insn_ld,
        insn_ll, insn_lld, insn_lui, insn_lw, insn_mfc0, insn_mtc0,
        insn_ori, insn_rfe, insn_sc, insn_scd, insn_sd, insn_sll,
        insn_sra, insn_srl, insn_subu, insn_sw, insn_tlbp, insn_tlbwi,
        insn_tlbwr, insn_xor, insn_xori
};

struct insn {
        enum opcode opcode;
        u32 match;
        enum fields fields;
};

/* This macro sets the non-variable bits of an instruction. */
#define M(a, b, c, d, e, f)                                     \
        ((a) << OP_SH                                           \
         | (b) << RS_SH                                         \
         | (c) << RT_SH                                         \
         | (d) << RD_SH                                         \
         | (e) << RE_SH                                         \
         | (f) << FUNC_SH)

static __initdata struct insn insn_table[] = {
        { insn_addiu, M(addiu_op,0,0,0,0,0), RS | RT | SIMM },
        { insn_addu, M(spec_op,0,0,0,0,addu_op), RS | RT | RD },
        { insn_and, M(spec_op,0,0,0,0,and_op), RS | RT | RD },
        { insn_andi, M(andi_op,0,0,0,0,0), RS | RT | UIMM },
        { insn_beq, M(beq_op,0,0,0,0,0), RS | RT | BIMM },
        { insn_beql, M(beql_op,0,0,0,0,0), RS | RT | BIMM },
        { insn_bgez, M(bcond_op,0,bgez_op,0,0,0), RS | BIMM },
        { insn_bgezl, M(bcond_op,0,bgezl_op,0,0,0), RS | BIMM },
        { insn_bltz, M(bcond_op,0,bltz_op,0,0,0), RS | BIMM },
        { insn_bltzl, M(bcond_op,0,bltzl_op,0,0,0), RS | BIMM },
        { insn_bne, M(bne_op,0,0,0,0,0), RS | RT | BIMM },
        { insn_daddiu, M(daddiu_op,0,0,0,0,0), RS | RT | SIMM },
        { insn_daddu, M(spec_op,0,0,0,0,daddu_op), RS | RT | RD },
        { insn_dmfc0, M(cop0_op,dmfc_op,0,0,0,0), RT | RD | SET},
        { insn_dmtc0, M(cop0_op,dmtc_op,0,0,0,0), RT | RD | SET},
        { insn_dsll, M(spec_op,0,0,0,0,dsll_op), RT | RD | RE },
        { insn_dsll32, M(spec_op,0,0,0,0,dsll32_op), RT | RD | RE },
        { insn_dsra, M(spec_op,0,0,0,0,dsra_op), RT | RD | RE },
        { insn_dsrl, M(spec_op,0,0,0,0,dsrl_op), RT | RD | RE },
        { insn_dsrl32, M(spec_op,0,0,0,0,dsrl32_op), RT | RD | RE },
        { insn_dsubu, M(spec_op,0,0,0,0,dsubu_op), RS | RT | RD },
        { insn_eret, M(cop0_op,cop_op,0,0,0,eret_op), 0 },
        { insn_j, M(j_op,0,0,0,0,0), JIMM },
        { insn_jal, M(jal_op,0,0,0,0,0), JIMM },
        { insn_jr, M(spec_op,0,0,0,0,jr_op), RS },
        { insn_ld, M(ld_op,0,0,0,0,0), RS | RT | SIMM },
        { insn_ll, M(ll_op,0,0,0,0,0), RS | RT | SIMM },
        { insn_lld, M(lld_op,0,0,0,0,0), RS | RT | SIMM },
        { insn_lui, M(lui_op,0,0,0,0,0), RT | SIMM },
        { insn_lw, M(lw_op,0,0,0,0,0), RS | RT | SIMM },
        { insn_mfc0, M(cop0_op,mfc_op,0,0,0,0), RT | RD | SET},
        { insn_mtc0, M(cop0_op,mtc_op,0,0,0,0), RT | RD | SET},
        { insn_ori, M(ori_op,0,0,0,0,0), RS | RT | UIMM },
        { insn_rfe, M(cop0_op,cop_op,0,0,0,rfe_op), 0 },
        { insn_sc, M(sc_op,0,0,0,0,0), RS | RT | SIMM },
        { insn_scd, M(scd_op,0,0,0,0,0), RS | RT | SIMM },
        { insn_sd, M(sd_op,0,0,0,0,0), RS | RT | SIMM },
        { insn_sll, M(spec_op,0,0,0,0,sll_op), RT | RD | RE },
        { insn_sra, M(spec_op,0,0,0,0,sra_op), RT | RD | RE },
        { insn_srl, M(spec_op,0,0,0,0,srl_op), RT | RD | RE },
        { insn_subu, M(spec_op,0,0,0,0,subu_op), RS | RT | RD },
        { insn_sw, M(sw_op,0,0,0,0,0), RS | RT | SIMM },
        { insn_tlbp, M(cop0_op,cop_op,0,0,0,tlbp_op), 0 },
        { insn_tlbwi, M(cop0_op,cop_op,0,0,0,tlbwi_op), 0 },
        { insn_tlbwr, M(cop0_op,cop_op,0,0,0,tlbwr_op), 0 },
        { insn_xor, M(spec_op,0,0,0,0,xor_op), RS | RT | RD },
        { insn_xori, M(xori_op,0,0,0,0,0), RS | RT | UIMM },
        { insn_invalid, 0, 0 }
};

#undef M

static __init u32 build_rs(u32 arg)
{
        if (arg & ~RS_MASK)
                printk(KERN_WARNING "TLB synthesizer field overflow\n");

        return (arg & RS_MASK) << RS_SH;
}

static __init u32 build_rt(u32 arg)
{
        if (arg & ~RT_MASK)
                printk(KERN_WARNING "TLB synthesizer field overflow\n");

        return (arg & RT_MASK) << RT_SH;
}

static __init u32 build_rd(u32 arg)
{
        if (arg & ~RD_MASK)
                printk(KERN_WARNING "TLB synthesizer field overflow\n");

        return (arg & RD_MASK) << RD_SH;
}

static __init u32 build_re(u32 arg)
{
        if (arg & ~RE_MASK)
                printk(KERN_WARNING "TLB synthesizer field overflow\n");

        return (arg & RE_MASK) << RE_SH;
}

static __init u32 build_simm(s32 arg)
{
        if (arg > 0x7fff || arg < -0x8000)
                printk(KERN_WARNING "TLB synthesizer field overflow\n");

        return arg & 0xffff;
}

static __init u32 build_uimm(u32 arg)
{
        if (arg & ~IMM_MASK)
                printk(KERN_WARNING "TLB synthesizer field overflow\n");

        return arg & IMM_MASK;
}

static __init u32 build_bimm(s32 arg)
{
        if (arg > 0x1ffff || arg < -0x20000)
                printk(KERN_WARNING "TLB synthesizer field overflow\n");

        if (arg & 0x3)
                printk(KERN_WARNING "Invalid TLB synthesizer branch target\n");

        return ((arg < 0) ? (1 << 15) : 0) | ((arg >> 2) & 0x7fff);
}

static __init u32 build_jimm(u32 arg)
{
        if (arg & ~((JIMM_MASK) << 2))
                printk(KERN_WARNING "TLB synthesizer field overflow\n");

        return (arg >> 2) & JIMM_MASK;
}

static __init u32 build_func(u32 arg)
{
        if (arg & ~FUNC_MASK)
                printk(KERN_WARNING "TLB synthesizer field overflow\n");

        return arg & FUNC_MASK;
}

static __init u32 build_set(u32 arg)
{
        if (arg & ~SET_MASK)
                printk(KERN_WARNING "TLB synthesizer field overflow\n");

        return arg & SET_MASK;
}

/*
 * The order of opcode arguments is implicitly left to right,
 * starting with RS and ending with FUNC or IMM.
 */
static void __init build_insn(u32 **buf, enum opcode opc, ...)
{
        struct insn *ip = NULL;
        unsigned int i;
        va_list ap;
        u32 op;

        for (i = 0; insn_table[i].opcode != insn_invalid; i++)
                if (insn_table[i].opcode == opc) {
                        ip = &insn_table[i];
                        break;
                }

        if (!ip)
                panic("Unsupported TLB synthesizer instruction %d", opc);

        op = ip->match;
        va_start(ap, opc);
        if (ip->fields & RS) op |= build_rs(va_arg(ap, u32));
        if (ip->fields & RT) op |= build_rt(va_arg(ap, u32));
        if (ip->fields & RD) op |= build_rd(va_arg(ap, u32));
        if (ip->fields & RE) op |= build_re(va_arg(ap, u32));
        if (ip->fields & SIMM) op |= build_simm(va_arg(ap, s32));
        if (ip->fields & UIMM) op |= build_uimm(va_arg(ap, u32));
        if (ip->fields & BIMM) op |= build_bimm(va_arg(ap, s32));
        if (ip->fields & JIMM) op |= build_jimm(va_arg(ap, u32));
        if (ip->fields & FUNC) op |= build_func(va_arg(ap, u32));
        if (ip->fields & SET) op |= build_set(va_arg(ap, u32));
        va_end(ap);

        **buf = op;
        (*buf)++;
}

#define I_u1u2u3(op)                                            \
        static inline void __init i##op(u32 **buf, unsigned int a,      \
                unsigned int b, unsigned int c)                 \
        {                                                       \
                build_insn(buf, insn##op, a, b, c);             \
        }

#define I_u2u1u3(op)                                            \
        static inline void __init i##op(u32 **buf, unsigned int a,      \
                unsigned int b, unsigned int c)                 \
        {                                                       \
                build_insn(buf, insn##op, b, a, c);             \
        }

#define I_u3u1u2(op)                                            \
        static inline void __init i##op(u32 **buf, unsigned int a,      \
                unsigned int b, unsigned int c)                 \
        {                                                       \
                build_insn(buf, insn##op, b, c, a);             \
        }

#define I_u1u2s3(op)                                            \
        static inline void __init i##op(u32 **buf, unsigned int a,      \
                unsigned int b, signed int c)                   \
        {                                                       \
                build_insn(buf, insn##op, a, b, c);             \
        }

#define I_u2s3u1(op)                                            \
        static inline void __init i##op(u32 **buf, unsigned int a,      \
                signed int b, unsigned int c)                   \
        {                                                       \
                build_insn(buf, insn##op, c, a, b);             \
        }

#define I_u2u1s3(op)                                            \
        static inline void __init i##op(u32 **buf, unsigned int a,      \
                unsigned int b, signed int c)                   \
        {                                                       \
                build_insn(buf, insn##op, b, a, c);             \
        }

#define I_u1u2(op)                                              \
        static inline void __init i##op(u32 **buf, unsigned int a,      \
                unsigned int b)                                 \
        {                                                       \
                build_insn(buf, insn##op, a, b);                \
        }

#define I_u1s2(op)                                              \
        static inline void __init i##op(u32 **buf, unsigned int a,      \
                signed int b)                                   \
        {                                                       \
                build_insn(buf, insn##op, a, b);                \
        }

#define I_u1(op)                                                \
        static inline void __init i##op(u32 **buf, unsigned int a)      \
        {                                                       \
                build_insn(buf, insn##op, a);                   \
        }

#define I_0(op)                                                 \
        static inline void __init i##op(u32 **buf)              \
        {                                                       \
                build_insn(buf, insn##op);                      \
        }

I_u2u1s3(_addiu);
I_u3u1u2(_addu);
I_u2u1u3(_andi);
I_u3u1u2(_and);
I_u1u2s3(_beq);
I_u1u2s3(_beql);
I_u1s2(_bgez);
I_u1s2(_bgezl);
I_u1s2(_bltz);
I_u1s2(_bltzl);
I_u1u2s3(_bne);
I_u1u2u3(_dmfc0);
I_u1u2u3(_dmtc0);
I_u2u1s3(_daddiu);
I_u3u1u2(_daddu);
I_u2u1u3(_dsll);
I_u2u1u3(_dsll32);
I_u2u1u3(_dsra);
I_u2u1u3(_dsrl);
I_u2u1u3(_dsrl32);
I_u3u1u2(_dsubu);
I_0(_eret);
I_u1(_j);
I_u1(_jal);
I_u1(_jr);
I_u2s3u1(_ld);
I_u2s3u1(_ll);
I_u2s3u1(_lld);
I_u1s2(_lui);
I_u2s3u1(_lw);
I_u1u2u3(_mfc0);
I_u1u2u3(_mtc0);
I_u2u1u3(_ori);
I_0(_rfe);
I_u2s3u1(_sc);
I_u2s3u1(_scd);
I_u2s3u1(_sd);
I_u2u1u3(_sll);
I_u2u1u3(_sra);
I_u2u1u3(_srl);
I_u3u1u2(_subu);
I_u2s3u1(_sw);
I_0(_tlbp);
I_0(_tlbwi);
I_0(_tlbwr);
I_u3u1u2(_xor)
I_u2u1u3(_xori);

/*
 * handling labels
 */

enum label_id {
        label_invalid,
        label_second_part,
        label_leave,
        label_vmalloc,
        label_vmalloc_done,
        label_tlbw_hazard,
        label_split,
        label_nopage_tlbl,
        label_nopage_tlbs,
        label_nopage_tlbm,
        label_smp_pgtable_change,
        label_r3000_write_probe_fail,
};

struct label {
        u32 *addr;
        enum label_id lab;
};

static __init void build_label(struct label **lab, u32 *addr,
                               enum label_id l)
{
        (*lab)->addr = addr;
        (*lab)->lab = l;
        (*lab)++;
}

#define L_LA(lb)                                                \
        static inline void l##lb(struct label **lab, u32 *addr) \
        {                                                       \
                build_label(lab, addr, label##lb);              \
        }

L_LA(_second_part)
L_LA(_leave)
L_LA(_vmalloc)
L_LA(_vmalloc_done)
L_LA(_tlbw_hazard)
L_LA(_split)
L_LA(_nopage_tlbl)
L_LA(_nopage_tlbs)
L_LA(_nopage_tlbm)
L_LA(_smp_pgtable_change)
L_LA(_r3000_write_probe_fail)

/* convenience macros for instructions */
#ifdef CONFIG_64BIT
# define i_LW(buf, rs, rt, off) i_ld(buf, rs, rt, off)
# define i_SW(buf, rs, rt, off) i_sd(buf, rs, rt, off)
# define i_SLL(buf, rs, rt, sh) i_dsll(buf, rs, rt, sh)
# define i_SRA(buf, rs, rt, sh) i_dsra(buf, rs, rt, sh)
# define i_SRL(buf, rs, rt, sh) i_dsrl(buf, rs, rt, sh)
# define i_MFC0(buf, rt, rd...) i_dmfc0(buf, rt, rd)
# define i_MTC0(buf, rt, rd...) i_dmtc0(buf, rt, rd)
# define i_ADDIU(buf, rs, rt, val) i_daddiu(buf, rs, rt, val)
# define i_ADDU(buf, rs, rt, rd) i_daddu(buf, rs, rt, rd)
# define i_SUBU(buf, rs, rt, rd) i_dsubu(buf, rs, rt, rd)
# define i_LL(buf, rs, rt, off) i_lld(buf, rs, rt, off)
# define i_SC(buf, rs, rt, off) i_scd(buf, rs, rt, off)
#else
# define i_LW(buf, rs, rt, off) i_lw(buf, rs, rt, off)
# define i_SW(buf, rs, rt, off) i_sw(buf, rs, rt, off)
# define i_SLL(buf, rs, rt, sh) i_sll(buf, rs, rt, sh)
# define i_SRA(buf, rs, rt, sh) i_sra(buf, rs, rt, sh)
# define i_SRL(buf, rs, rt, sh) i_srl(buf, rs, rt, sh)
# define i_MFC0(buf, rt, rd...) i_mfc0(buf, rt, rd)
# define i_MTC0(buf, rt, rd...) i_mtc0(buf, rt, rd)
# define i_ADDIU(buf, rs, rt, val) i_addiu(buf, rs, rt, val)
# define i_ADDU(buf, rs, rt, rd) i_addu(buf, rs, rt, rd)
# define i_SUBU(buf, rs, rt, rd) i_subu(buf, rs, rt, rd)
# define i_LL(buf, rs, rt, off) i_ll(buf, rs, rt, off)
# define i_SC(buf, rs, rt, off) i_sc(buf, rs, rt, off)
#endif

#define i_b(buf, off) i_beq(buf, 0, 0, off)
#define i_beqz(buf, rs, off) i_beq(buf, rs, 0, off)
#define i_beqzl(buf, rs, off) i_beql(buf, rs, 0, off)
#define i_bnez(buf, rs, off) i_bne(buf, rs, 0, off)
#define i_bnezl(buf, rs, off) i_bnel(buf, rs, 0, off)
#define i_move(buf, a, b) i_ADDU(buf, a, 0, b)
#define i_nop(buf) i_sll(buf, 0, 0, 0)
#define i_ssnop(buf) i_sll(buf, 0, 0, 1)
#define i_ehb(buf) i_sll(buf, 0, 0, 3)

#ifdef CONFIG_64BIT
static __init int __attribute__((unused)) in_compat_space_p(long addr)
{
        /* Is this address in 32bit compat space? */
        return (((addr) & 0xffffffff00000000L) == 0xffffffff00000000L);
}

static __init int __attribute__((unused)) rel_highest(long val)
{
        return ((((val + 0x800080008000L) >> 48) & 0xffff) ^ 0x8000) - 0x8000;
}

static __init int __attribute__((unused)) rel_higher(long val)
{
        return ((((val + 0x80008000L) >> 32) & 0xffff) ^ 0x8000) - 0x8000;
}
#endif

static __init int rel_hi(long val)
{
        return ((((val + 0x8000L) >> 16) & 0xffff) ^ 0x8000) - 0x8000;
}

static __init int rel_lo(long val)
{
        return ((val & 0xffff) ^ 0x8000) - 0x8000;
}

static __init void i_LA_mostly(u32 **buf, unsigned int rs, long addr)
{
#ifdef CONFIG_64BIT
        if (!in_compat_space_p(addr)) {
                i_lui(buf, rs, rel_highest(addr));
                if (rel_higher(addr))
                        i_daddiu(buf, rs, rs, rel_higher(addr));
                if (rel_hi(addr)) {
                        i_dsll(buf, rs, rs, 16);
                        i_daddiu(buf, rs, rs, rel_hi(addr));
                        i_dsll(buf, rs, rs, 16);
                } else
                        i_dsll32(buf, rs, rs, 0);
        } else
#endif
                i_lui(buf, rs, rel_hi(addr));
}

static __init void __attribute__((unused)) i_LA(u32 **buf, unsigned int rs,
                                                long addr)
{
        i_LA_mostly(buf, rs, addr);
        if (rel_lo(addr))
                i_ADDIU(buf, rs, rs, rel_lo(addr));
}

/*
 * handle relocations
 */

struct reloc {
        u32 *addr;
        unsigned int type;
        enum label_id lab;
};

static __init void r_mips_pc16(struct reloc **rel, u32 *addr,
                               enum label_id l)
{
        (*rel)->addr = addr;
        (*rel)->type = R_MIPS_PC16;
        (*rel)->lab = l;
        (*rel)++;
}

static inline void __resolve_relocs(struct reloc *rel, struct label *lab)
{
        long laddr = (long)lab->addr;
        long raddr = (long)rel->addr;

        switch (rel->type) {
        case R_MIPS_PC16:
                *rel->addr |= build_bimm(laddr - (raddr + 4));
                break;

        default:
                panic("Unsupported TLB synthesizer relocation %d",
                      rel->type);
        }
}

static __init void resolve_relocs(struct reloc *rel, struct label *lab)
{
        struct label *l;

        for (; rel->lab != label_invalid; rel++)
                for (l = lab; l->lab != label_invalid; l++)
                        if (rel->lab == l->lab)
                                __resolve_relocs(rel, l);
}

static __init void move_relocs(struct reloc *rel, u32 *first, u32 *end,
                               long off)
{
        for (; rel->lab != label_invalid; rel++)
                if (rel->addr >= first && rel->addr < end)
                        rel->addr += off;
}

static __init void move_labels(struct label *lab, u32 *first, u32 *end,
                               long off)
{
        for (; lab->lab != label_invalid; lab++)
                if (lab->addr >= first && lab->addr < end)
                        lab->addr += off;
}

static __init void copy_handler(struct reloc *rel, struct label *lab,
                                u32 *first, u32 *end, u32 *target)
{
        long off = (long)(target - first);

        memcpy(target, first, (end - first) * sizeof(u32));

        move_relocs(rel, first, end, off);
        move_labels(lab, first, end, off);
}

static __init int __attribute__((unused)) insn_has_bdelay(struct reloc *rel,
                                                          u32 *addr)
{
        for (; rel->lab != label_invalid; rel++) {
                if (rel->addr == addr
                    && (rel->type == R_MIPS_PC16
                        || rel->type == R_MIPS_26))
                        return 1;
        }

        return 0;
}

/* convenience functions for labeled branches */
static void __init __attribute__((unused))
        il_bltz(u32 **p, struct reloc **r, unsigned int reg, enum label_id l)
{
        r_mips_pc16(r, *p, l);
        i_bltz(p, reg, 0);
}

static void __init __attribute__((unused)) il_b(u32 **p, struct reloc **r,
                                         enum label_id l)
{
        r_mips_pc16(r, *p, l);
        i_b(p, 0);
}

static void __init il_beqz(u32 **p, struct reloc **r, unsigned int reg,
                    enum label_id l)
{
        r_mips_pc16(r, *p, l);
        i_beqz(p, reg, 0);
}

static void __init __attribute__((unused))
il_beqzl(u32 **p, struct reloc **r, unsigned int reg, enum label_id l)
{
        r_mips_pc16(r, *p, l);
        i_beqzl(p, reg, 0);
}

static void __init il_bnez(u32 **p, struct reloc **r, unsigned int reg,
                    enum label_id l)
{
        r_mips_pc16(r, *p, l);
        i_bnez(p, reg, 0);
}

static void __init il_bgezl(u32 **p, struct reloc **r, unsigned int reg,
                     enum label_id l)
{
        r_mips_pc16(r, *p, l);
        i_bgezl(p, reg, 0);
}

/* The only general purpose registers allowed in TLB handlers. */
#define K0              26
#define K1              27

/* Some CP0 registers */
#define C0_INDEX        0, 0
#define C0_ENTRYLO0     2, 0
#define C0_TCBIND       2, 2
#define C0_ENTRYLO1     3, 0
#define C0_CONTEXT      4, 0
#define C0_BADVADDR     8, 0
#define C0_ENTRYHI      10, 0
#define C0_EPC          14, 0
#define C0_XCONTEXT     20, 0

#ifdef CONFIG_64BIT
# define GET_CONTEXT(buf, reg) i_MFC0(buf, reg, C0_XCONTEXT)
#else
# define GET_CONTEXT(buf, reg) i_MFC0(buf, reg, C0_CONTEXT)
#endif

/* The worst case length of the handler is around 18 instructions for
 * R3000-style TLBs and up to 63 instructions for R4000-style TLBs.
 * Maximum space available is 32 instructions for R3000 and 64
 * instructions for R4000.
 *
 * We deliberately chose a buffer size of 128, so we won't scribble
 * over anything important on overflow before we panic.
 */
static __initdata u32 tlb_handler[128];

/* simply assume worst case size for labels and relocs */
static __initdata struct label labels[128];
static __initdata struct reloc relocs[128];

/*
 * The R3000 TLB handler is simple.
 */
static void __init build_r3000_tlb_refill_handler(void)
{
        long pgdc = (long)pgd_current;
        u32 *p;
        int i;

        memset(tlb_handler, 0, sizeof(tlb_handler));
        p = tlb_handler;

        i_mfc0(&p, K0, C0_BADVADDR);
        i_lui(&p, K1, rel_hi(pgdc)); /* cp0 delay */
        i_lw(&p, K1, rel_lo(pgdc), K1);
        i_srl(&p, K0, K0, 22); /* load delay */
        i_sll(&p, K0, K0, 2);
        i_addu(&p, K1, K1, K0);
        i_mfc0(&p, K0, C0_CONTEXT);
        i_lw(&p, K1, 0, K1); /* cp0 delay */
        i_andi(&p, K0, K0, 0xffc); /* load delay */
        i_addu(&p, K1, K1, K0);
        i_lw(&p, K0, 0, K1);
        i_nop(&p); /* load delay */
        i_mtc0(&p, K0, C0_ENTRYLO0);
        i_mfc0(&p, K1, C0_EPC); /* cp0 delay */
        i_tlbwr(&p); /* cp0 delay */
        i_jr(&p, K1);
        i_rfe(&p); /* branch delay */

        if (p > tlb_handler + 32)
                panic("TLB refill handler space exceeded");

        pr_info("Synthesized TLB refill handler (%u instructions).\n",
                (unsigned int)(p - tlb_handler));

        pr_debug("\t.set push\n");
        pr_debug("\t.set noreorder\n");
        for (i = 0; i < (p - tlb_handler); i++)
                pr_debug("\t.word 0x%08x\n", tlb_handler[i]);
        pr_debug("\t.set pop\n");

        memcpy((void *)ebase, tlb_handler, 0x80);
}

/*
 * The R4000 TLB handler is much more complicated. We have two
 * consecutive handler areas with 32 instructions space each.
 * Since they aren't used at the same time, we can overflow in the
 * other one.To keep things simple, we first assume linear space,
 * then we relocate it to the final handler layout as needed.
 */
static __initdata u32 final_handler[64];

/*
 * Hazards
 *
 * From the IDT errata for the QED RM5230 (Nevada), processor revision 1.0:
 * 2. A timing hazard exists for the TLBP instruction.
 *
 *      stalling_instruction
 *      TLBP
 *
 * The JTLB is being read for the TLBP throughout the stall generated by the
 * previous instruction. This is not really correct as the stalling instruction
 * can modify the address used to access the JTLB.  The failure symptom is that
 * the TLBP instruction will use an address created for the stalling instruction
 * and not the address held in C0_ENHI and thus report the wrong results.
 *
 * The software work-around is to not allow the instruction preceding the TLBP
 * to stall - make it an NOP or some other instruction guaranteed not to stall.
 *
 * Errata 2 will not be fixed.  This errata is also on the R5000.
 *
 * As if we MIPS hackers wouldn't know how to nop pipelines happy ...
 */
static __init void __attribute__((unused)) build_tlb_probe_entry(u32 **p)
{
        switch (current_cpu_data.cputype) {
        /* Found by experiment: R4600 v2.0 needs this, too.  */
        case CPU_R4600:
        case CPU_R5000:
        case CPU_R5000A:
        case CPU_NEVADA:
                i_nop(p);
                i_tlbp(p);
                break;

        default:
                i_tlbp(p);
                break;
        }
}

/*
 * Write random or indexed TLB entry, and care about the hazards from
 * the preceeding mtc0 and for the following eret.
 */
enum tlb_write_entry { tlb_random, tlb_indexed };

static __init void build_tlb_write_entry(u32 **p, struct label **l,
                                         struct reloc **r,
                                         enum tlb_write_entry wmode)
{
        void(*tlbw)(u32 **) = NULL;

        switch (wmode) {
        case tlb_random: tlbw = i_tlbwr; break;
        case tlb_indexed: tlbw = i_tlbwi; break;
        }

        switch (current_cpu_data.cputype) {
        case CPU_R4000PC:
        case CPU_R4000SC:
        case CPU_R4000MC:
        case CPU_R4400PC:
        case CPU_R4400SC:
        case CPU_R4400MC:
                /*
                 * This branch uses up a mtc0 hazard nop slot and saves
                 * two nops after the tlbw instruction.
                 */
                il_bgezl(p, r, 0, label_tlbw_hazard);
                tlbw(p);
                l_tlbw_hazard(l, *p);
                i_nop(p);
                break;

        case CPU_R4600:
        case CPU_R4700:
        case CPU_R5000:
        case CPU_R5000A:
                i_nop(p);
                tlbw(p);
                i_nop(p);
                break;

        case CPU_R4300:
        case CPU_5KC:
        case CPU_TX49XX:
        case CPU_AU1000:
        case CPU_AU1100:
        case CPU_AU1500:
        case CPU_AU1550:
        case CPU_AU1200:
        case CPU_PR4450:
                i_nop(p);
                tlbw(p);
                break;

        case CPU_R10000:
        case CPU_R12000:
        case CPU_R14000:
        case CPU_4KC:
        case CPU_SB1:
        case CPU_SB1A:
        case CPU_4KSC:
        case CPU_20KC:
        case CPU_25KF:
                tlbw(p);
                break;

        case CPU_NEVADA:
                i_nop(p); /* QED specifies 2 nops hazard */
                /*
                 * This branch uses up a mtc0 hazard nop slot and saves
                 * a nop after the tlbw instruction.
                 */
                il_bgezl(p, r, 0, label_tlbw_hazard);
                tlbw(p);
                l_tlbw_hazard(l, *p);
                break;

        case CPU_RM7000:
                i_nop(p);
                i_nop(p);
                i_nop(p);
                i_nop(p);
                tlbw(p);
                break;

        case CPU_4KEC:
        case CPU_24K:
        case CPU_34K:
        case CPU_74K:
                i_ehb(p);
                tlbw(p);
                break;

        case CPU_RM9000:
                /*
                 * When the JTLB is updated by tlbwi or tlbwr, a subsequent
                 * use of the JTLB for instructions should not occur for 4
                 * cpu cycles and use for data translations should not occur
                 * for 3 cpu cycles.
                 */
                i_ssnop(p);
                i_ssnop(p);
                i_ssnop(p);
                i_ssnop(p);
                tlbw(p);
                i_ssnop(p);
                i_ssnop(p);
                i_ssnop(p);
                i_ssnop(p);
                break;

        case CPU_VR4111:
        case CPU_VR4121:
        case CPU_VR4122:
        case CPU_VR4181:
        case CPU_VR4181A:
                i_nop(p);
                i_nop(p);
                tlbw(p);
                i_nop(p);
                i_nop(p);
                break;

        case CPU_VR4131:
        case CPU_VR4133:
        case CPU_R5432:
                i_nop(p);
                i_nop(p);
                tlbw(p);
                break;

        default:
                panic("No TLB refill handler yet (CPU type: %d)",
                      current_cpu_data.cputype);
                break;
        }
}

#ifdef CONFIG_64BIT
/*
 * TMP and PTR are scratch.
 * TMP will be clobbered, PTR will hold the pmd entry.
 */
static __init void
build_get_pmde64(u32 **p, struct label **l, struct reloc **r,
                 unsigned int tmp, unsigned int ptr)
{
        long pgdc = (long)pgd_current;

        /*
         * The vmalloc handling is not in the hotpath.
         */
        i_dmfc0(p, tmp, C0_BADVADDR);
        il_bltz(p, r, tmp, label_vmalloc);
        /* No i_nop needed here, since the next insn doesn't touch TMP. */

#ifdef CONFIG_SMP
# ifdef  CONFIG_MIPS_MT_SMTC
        /*
         * SMTC uses TCBind value as "CPU" index
         */
        i_mfc0(p, ptr, C0_TCBIND);
        i_dsrl(p, ptr, ptr, 19);
# else
        /*
         * 64 bit SMP running in XKPHYS has smp_processor_id() << 3
         * stored in CONTEXT.
         */
        i_dmfc0(p, ptr, C0_CONTEXT);
        i_dsrl(p, ptr, ptr, 23);
#endif
        i_LA_mostly(p, tmp, pgdc);
        i_daddu(p, ptr, ptr, tmp);
        i_dmfc0(p, tmp, C0_BADVADDR);
        i_ld(p, ptr, rel_lo(pgdc), ptr);
#else
        i_LA_mostly(p, ptr, pgdc);
        i_ld(p, ptr, rel_lo(pgdc), ptr);
#endif

        l_vmalloc_done(l, *p);

        if (PGDIR_SHIFT - 3 < 32)               /* get pgd offset in bytes */
                i_dsrl(p, tmp, tmp, PGDIR_SHIFT-3);
        else
                i_dsrl32(p, tmp, tmp, PGDIR_SHIFT - 3 - 32);

        i_andi(p, tmp, tmp, (PTRS_PER_PGD - 1)<<3);
        i_daddu(p, ptr, ptr, tmp); /* add in pgd offset */
        i_dmfc0(p, tmp, C0_BADVADDR); /* get faulting address */
        i_ld(p, ptr, 0, ptr); /* get pmd pointer */
        i_dsrl(p, tmp, tmp, PMD_SHIFT-3); /* get pmd offset in bytes */
        i_andi(p, tmp, tmp, (PTRS_PER_PMD - 1)<<3);
        i_daddu(p, ptr, ptr, tmp); /* add in pmd offset */
}

/*
 * BVADDR is the faulting address, PTR is scratch.
 * PTR will hold the pgd for vmalloc.
 */
static __init void
build_get_pgd_vmalloc64(u32 **p, struct label **l, struct reloc **r,
                        unsigned int bvaddr, unsigned int ptr)
{
        long swpd = (long)swapper_pg_dir;

        l_vmalloc(l, *p);
        i_LA(p, ptr, VMALLOC_START);
        i_dsubu(p, bvaddr, bvaddr, ptr);

        if (in_compat_space_p(swpd) && !rel_lo(swpd)) {
                il_b(p, r, label_vmalloc_done);
                i_lui(p, ptr, rel_hi(swpd));
        } else {
                i_LA_mostly(p, ptr, swpd);
                il_b(p, r, label_vmalloc_done);
                i_daddiu(p, ptr, ptr, rel_lo(swpd));
        }
}

#else /* !CONFIG_64BIT */

/*
 * TMP and PTR are scratch.
 * TMP will be clobbered, PTR will hold the pgd entry.
 */
static __init void __attribute__((unused))
build_get_pgde32(u32 **p, unsigned int tmp, unsigned int ptr)
{
        long pgdc = (long)pgd_current;

        /* 32 bit SMP has smp_processor_id() stored in CONTEXT. */
#ifdef CONFIG_SMP
#ifdef  CONFIG_MIPS_MT_SMTC
        /*
         * SMTC uses TCBind value as "CPU" index
         */
        i_mfc0(p, ptr, C0_TCBIND);
        i_LA_mostly(p, tmp, pgdc);
        i_srl(p, ptr, ptr, 19);
#else
        /*
         * smp_processor_id() << 3 is stored in CONTEXT.
         */
        i_mfc0(p, ptr, C0_CONTEXT);
        i_LA_mostly(p, tmp, pgdc);
        i_srl(p, ptr, ptr, 23);
#endif
        i_addu(p, ptr, tmp, ptr);
#else
        i_LA_mostly(p, ptr, pgdc);
#endif
        i_mfc0(p, tmp, C0_BADVADDR); /* get faulting address */
        i_lw(p, ptr, rel_lo(pgdc), ptr);
        i_srl(p, tmp, tmp, PGDIR_SHIFT); /* get pgd only bits */
        i_sll(p, tmp, tmp, PGD_T_LOG2);
        i_addu(p, ptr, ptr, tmp); /* add in pgd offset */
}

#endif /* !CONFIG_64BIT */

static __init void build_adjust_context(u32 **p, unsigned int ctx)
{
        unsigned int shift = 4 - (PTE_T_LOG2 + 1) + PAGE_SHIFT - 12;
        unsigned int mask = (PTRS_PER_PTE / 2 - 1) << (PTE_T_LOG2 + 1);

        switch (current_cpu_data.cputype) {
        case CPU_VR41XX:
        case CPU_VR4111:
        case CPU_VR4121:
        case CPU_VR4122:
        case CPU_VR4131:
        case CPU_VR4181:
        case CPU_VR4181A:
        case CPU_VR4133:
                shift += 2;
                break;

        default:
                break;
        }

        if (shift)
                i_SRL(p, ctx, ctx, shift);
        i_andi(p, ctx, ctx, mask);
}

static __init void build_get_ptep(u32 **p, unsigned int tmp, unsigned int ptr)
{
        /*
         * Bug workaround for the Nevada. It seems as if under certain
         * circumstances the move from cp0_context might produce a
         * bogus result when the mfc0 instruction and its consumer are
         * in a different cacheline or a load instruction, probably any
         * memory reference, is between them.
         */
        switch (current_cpu_data.cputype) {
        case CPU_NEVADA:
                i_LW(p, ptr, 0, ptr);
                GET_CONTEXT(p, tmp); /* get context reg */
                break;

        default:
                GET_CONTEXT(p, tmp); /* get context reg */
                i_LW(p, ptr, 0, ptr);
                break;
        }

        build_adjust_context(p, tmp);
        i_ADDU(p, ptr, ptr, tmp); /* add in offset */
}

static __init void build_update_entries(u32 **p, unsigned int tmp,
                                        unsigned int ptep)
{
        /*
         * 64bit address support (36bit on a 32bit CPU) in a 32bit
         * Kernel is a special case. Only a few CPUs use it.
         */
#ifdef CONFIG_64BIT_PHYS_ADDR
        if (cpu_has_64bits) {
                i_ld(p, tmp, 0, ptep); /* get even pte */
                i_ld(p, ptep, sizeof(pte_t), ptep); /* get odd pte */
                i_dsrl(p, tmp, tmp, 6); /* convert to entrylo0 */
                i_mtc0(p, tmp, C0_ENTRYLO0); /* load it */
                i_dsrl(p, ptep, ptep, 6); /* convert to entrylo1 */
                i_mtc0(p, ptep, C0_ENTRYLO1); /* load it */
        } else {
                int pte_off_even = sizeof(pte_t) / 2;
                int pte_off_odd = pte_off_even + sizeof(pte_t);

                /* The pte entries are pre-shifted */
                i_lw(p, tmp, pte_off_even, ptep); /* get even pte */
                i_mtc0(p, tmp, C0_ENTRYLO0); /* load it */
                i_lw(p, ptep, pte_off_odd, ptep); /* get odd pte */
                i_mtc0(p, ptep, C0_ENTRYLO1); /* load it */
        }
#else
        i_LW(p, tmp, 0, ptep); /* get even pte */
        i_LW(p, ptep, sizeof(pte_t), ptep); /* get odd pte */
        if (r45k_bvahwbug())
                build_tlb_probe_entry(p);
        i_SRL(p, tmp, tmp, 6); /* convert to entrylo0 */
        if (r4k_250MHZhwbug())
                i_mtc0(p, 0, C0_ENTRYLO0);
        i_mtc0(p, tmp, C0_ENTRYLO0); /* load it */
        i_SRL(p, ptep, ptep, 6); /* convert to entrylo1 */
        if (r45k_bvahwbug())
                i_mfc0(p, tmp, C0_INDEX);
        if (r4k_250MHZhwbug())
                i_mtc0(p, 0, C0_ENTRYLO1);
        i_mtc0(p, ptep, C0_ENTRYLO1); /* load it */
#endif
}

static void __init build_r4000_tlb_refill_handler(void)
{
        u32 *p = tlb_handler;
        struct label *l = labels;
        struct reloc *r = relocs;
        u32 *f;
        unsigned int final_len;
        int i;

        memset(tlb_handler, 0, sizeof(tlb_handler));
        memset(labels, 0, sizeof(labels));
        memset(relocs, 0, sizeof(relocs));
        memset(final_handler, 0, sizeof(final_handler));

        /*
         * create the plain linear handler
         */
        if (bcm1250_m3_war()) {
                i_MFC0(&p, K0, C0_BADVADDR);
                i_MFC0(&p, K1, C0_ENTRYHI);
                i_xor(&p, K0, K0, K1);
                i_SRL(&p, K0, K0, PAGE_SHIFT + 1);
                il_bnez(&p, &r, K0, label_leave);
                /* No need for i_nop */
        }

#ifdef CONFIG_64BIT
        build_get_pmde64(&p, &l, &r, K0, K1); /* get pmd in K1 */
#else
        build_get_pgde32(&p, K0, K1); /* get pgd in K1 */
#endif

        build_get_ptep(&p, K0, K1);
        build_update_entries(&p, K0, K1);
        build_tlb_write_entry(&p, &l, &r, tlb_random);
        l_leave(&l, p);
        i_eret(&p); /* return from trap */

#ifdef CONFIG_64BIT
        build_get_pgd_vmalloc64(&p, &l, &r, K0, K1);
#endif

        /*
         * Overflow check: For the 64bit handler, we need at least one
         * free instruction slot for the wrap-around branch. In worst
         * case, if the intended insertion point is a delay slot, we
         * need three, with the second nop'ed and the third being
         * unused.
         */
#ifdef CONFIG_32BIT
        if ((p - tlb_handler) > 64)
                panic("TLB refill handler space exceeded");
#else
        if (((p - tlb_handler) > 63)
            || (((p - tlb_handler) > 61)
                && insn_has_bdelay(relocs, tlb_handler + 29)))
                panic("TLB refill handler space exceeded");
#endif

        /*
         * Now fold the handler in the TLB refill handler space.
         */
#ifdef CONFIG_32BIT
        f = final_handler;
        /* Simplest case, just copy the handler. */
        copy_handler(relocs, labels, tlb_handler, p, f);
        final_len = p - tlb_handler;
#else /* CONFIG_64BIT */
        f = final_handler + 32;
        if ((p - tlb_handler) <= 32) {
                /* Just copy the handler. */
                copy_handler(relocs, labels, tlb_handler, p, f);
                final_len = p - tlb_handler;
        } else {
                u32 *split = tlb_handler + 30;

                /*
                 * Find the split point.
                 */
                if (insn_has_bdelay(relocs, split - 1))
                        split--;

                /* Copy first part of the handler. */
                copy_handler(relocs, labels, tlb_handler, split, f);
                f += split - tlb_handler;

                /* Insert branch. */
                l_split(&l, final_handler);
                il_b(&f, &r, label_split);
                if (insn_has_bdelay(relocs, split))
                        i_nop(&f);
                else {
                        copy_handler(relocs, labels, split, split + 1, f);
                        move_labels(labels, f, f + 1, -1);
                        f++;
                        split++;
                }

                /* Copy the rest of the handler. */
                copy_handler(relocs, labels, split, p, final_handler);
                final_len = (f - (final_handler + 32)) + (p - split);
        }
#endif /* CONFIG_64BIT */

        resolve_relocs(relocs, labels);
        pr_info("Synthesized TLB refill handler (%u instructions).\n",
                final_len);

        f = final_handler;
#ifdef CONFIG_64BIT
        if (final_len > 32)
                final_len = 64;
        else
                f = final_handler + 32;
#endif /* CONFIG_64BIT */
        pr_debug("\t.set push\n");
        pr_debug("\t.set noreorder\n");
        for (i = 0; i < final_len; i++)
                pr_debug("\t.word 0x%08x\n", f[i]);
        pr_debug("\t.set pop\n");

        memcpy((void *)ebase, final_handler, 0x100);
}

/*
 * TLB load/store/modify handlers.
 *
 * Only the fastpath gets synthesized at runtime, the slowpath for
 * do_page_fault remains normal asm.
 */
extern void tlb_do_page_fault_0(void);
extern void tlb_do_page_fault_1(void);

#define __tlb_handler_align \
        __attribute__((__aligned__(1 << CONFIG_MIPS_L1_CACHE_SHIFT)))

/*
 * 128 instructions for the fastpath handler is generous and should
 * never be exceeded.
 */
#define FASTPATH_SIZE 128

u32 __tlb_handler_align handle_tlbl[FASTPATH_SIZE];
u32 __tlb_handler_align handle_tlbs[FASTPATH_SIZE];
u32 __tlb_handler_align handle_tlbm[FASTPATH_SIZE];

static void __init
iPTE_LW(u32 **p, struct label **l, unsigned int pte, unsigned int ptr)
{
#ifdef CONFIG_SMP
# ifdef CONFIG_64BIT_PHYS_ADDR
        if (cpu_has_64bits)
                i_lld(p, pte, 0, ptr);
        else
# endif
                i_LL(p, pte, 0, ptr);
#else
# ifdef CONFIG_64BIT_PHYS_ADDR
        if (cpu_has_64bits)
                i_ld(p, pte, 0, ptr);
        else
# endif
                i_LW(p, pte, 0, ptr);
#endif
}

static void __init
iPTE_SW(u32 **p, struct reloc **r, unsigned int pte, unsigned int ptr,
        unsigned int mode)
{
#ifdef CONFIG_64BIT_PHYS_ADDR
        unsigned int hwmode = mode & (_PAGE_VALID | _PAGE_DIRTY);
#endif

        i_ori(p, pte, pte, mode);
#ifdef CONFIG_SMP
# ifdef CONFIG_64BIT_PHYS_ADDR
        if (cpu_has_64bits)
                i_scd(p, pte, 0, ptr);
        else
# endif
                i_SC(p, pte, 0, ptr);

        if (r10000_llsc_war())
                il_beqzl(p, r, pte, label_smp_pgtable_change);
        else
                il_beqz(p, r, pte, label_smp_pgtable_change);

# ifdef CONFIG_64BIT_PHYS_ADDR
        if (!cpu_has_64bits) {
                /* no i_nop needed */
                i_ll(p, pte, sizeof(pte_t) / 2, ptr);
                i_ori(p, pte, pte, hwmode);
                i_sc(p, pte, sizeof(pte_t) / 2, ptr);
                il_beqz(p, r, pte, label_smp_pgtable_change);
                /* no i_nop needed */
                i_lw(p, pte, 0, ptr);
        } else
                i_nop(p);
# else
        i_nop(p);
# endif
#else
# ifdef CONFIG_64BIT_PHYS_ADDR
        if (cpu_has_64bits)
                i_sd(p, pte, 0, ptr);
        else
# endif
                i_SW(p, pte, 0, ptr);

# ifdef CONFIG_64BIT_PHYS_ADDR
        if (!cpu_has_64bits) {
                i_lw(p, pte, sizeof(pte_t) / 2, ptr);
                i_ori(p, pte, pte, hwmode);
                i_sw(p, pte, sizeof(pte_t) / 2, ptr);
                i_lw(p, pte, 0, ptr);
        }
# endif
#endif
}

/*
 * Check if PTE is present, if not then jump to LABEL. PTR points to
 * the page table where this PTE is located, PTE will be re-loaded
 * with it's original value.
 */
static void __init
build_pte_present(u32 **p, struct label **l, struct reloc **r,
                  unsigned int pte, unsigned int ptr, enum label_id lid)
{
        i_andi(p, pte, pte, _PAGE_PRESENT | _PAGE_READ);
        i_xori(p, pte, pte, _PAGE_PRESENT | _PAGE_READ);
        il_bnez(p, r, pte, lid);
        iPTE_LW(p, l, pte, ptr);
}

/* Make PTE valid, store result in PTR. */
static void __init
build_make_valid(u32 **p, struct reloc **r, unsigned int pte,
                 unsigned int ptr)
{
        unsigned int mode = _PAGE_VALID | _PAGE_ACCESSED;

        iPTE_SW(p, r, pte, ptr, mode);
}

/*
 * Check if PTE can be written to, if not branch to LABEL. Regardless
 * restore PTE with value from PTR when done.
 */
static void __init
build_pte_writable(u32 **p, struct label **l, struct reloc **r,
                   unsigned int pte, unsigned int ptr, enum label_id lid)
{
        i_andi(p, pte, pte, _PAGE_PRESENT | _PAGE_WRITE);
        i_xori(p, pte, pte, _PAGE_PRESENT | _PAGE_WRITE);
        il_bnez(p, r, pte, lid);
        iPTE_LW(p, l, pte, ptr);
}

/* Make PTE writable, update software status bits as well, then store
 * at PTR.
 */
static void __init
build_make_write(u32 **p, struct reloc **r, unsigned int pte,
                 unsigned int ptr)
{
        unsigned int mode = (_PAGE_ACCESSED | _PAGE_MODIFIED | _PAGE_VALID
                             | _PAGE_DIRTY);

        iPTE_SW(p, r, pte, ptr, mode);
}

/*
 * Check if PTE can be modified, if not branch to LABEL. Regardless
 * restore PTE with value from PTR when done.
 */
static void __init
build_pte_modifiable(u32 **p, struct label **l, struct reloc **r,
                     unsigned int pte, unsigned int ptr, enum label_id lid)
{
        i_andi(p, pte, pte, _PAGE_WRITE);
        il_beqz(p, r, pte, lid);
        iPTE_LW(p, l, pte, ptr);
}

/*
 * R3000 style TLB load/store/modify handlers.
 */

/*
 * This places the pte into ENTRYLO0 and writes it with tlbwi.
 * Then it returns.
 */
static void __init
build_r3000_pte_reload_tlbwi(u32 **p, unsigned int pte, unsigned int tmp)
{
        i_mtc0(p, pte, C0_ENTRYLO0); /* cp0 delay */
        i_mfc0(p, tmp, C0_EPC); /* cp0 delay */
        i_tlbwi(p);
        i_jr(p, tmp);
        i_rfe(p); /* branch delay */
}

/*
 * This places the pte into ENTRYLO0 and writes it with tlbwi
 * or tlbwr as appropriate.  This is because the index register
 * may have the probe fail bit set as a result of a trap on a
 * kseg2 access, i.e. without refill.  Then it returns.
 */
static void __init
build_r3000_tlb_reload_write(u32 **p, struct label **l, struct reloc **r,
                             unsigned int pte, unsigned int tmp)
{
        i_mfc0(p, tmp, C0_INDEX);
        i_mtc0(p, pte, C0_ENTRYLO0); /* cp0 delay */
        il_bltz(p, r, tmp, label_r3000_write_probe_fail); /* cp0 delay */
        i_mfc0(p, tmp, C0_EPC); /* branch delay */
        i_tlbwi(p); /* cp0 delay */
        i_jr(p, tmp);
        i_rfe(p); /* branch delay */
        l_r3000_write_probe_fail(l, *p);
        i_tlbwr(p); /* cp0 delay */
        i_jr(p, tmp);
        i_rfe(p); /* branch delay */
}

static void __init
build_r3000_tlbchange_handler_head(u32 **p, unsigned int pte,
                                   unsigned int ptr)
{
        long pgdc = (long)pgd_current;

        i_mfc0(p, pte, C0_BADVADDR);
        i_lui(p, ptr, rel_hi(pgdc)); /* cp0 delay */
        i_lw(p, ptr, rel_lo(pgdc), ptr);
        i_srl(p, pte, pte, 22); /* load delay */
        i_sll(p, pte, pte, 2);
        i_addu(p, ptr, ptr, pte);
        i_mfc0(p, pte, C0_CONTEXT);
        i_lw(p, ptr, 0, ptr); /* cp0 delay */
        i_andi(p, pte, pte, 0xffc); /* load delay */
        i_addu(p, ptr, ptr, pte);
        i_lw(p, pte, 0, ptr);
        i_tlbp(p); /* load delay */
}

static void __init build_r3000_tlb_load_handler(void)
{
        u32 *p = handle_tlbl;
        struct label *l = labels;
        struct reloc *r = relocs;
        int i;

        memset(handle_tlbl, 0, sizeof(handle_tlbl));
        memset(labels, 0, sizeof(labels));
        memset(relocs, 0, sizeof(relocs));

        build_r3000_tlbchange_handler_head(&p, K0, K1);
        build_pte_present(&p, &l, &r, K0, K1, label_nopage_tlbl);
        i_nop(&p); /* load delay */
        build_make_valid(&p, &r, K0, K1);
        build_r3000_tlb_reload_write(&p, &l, &r, K0, K1);

        l_nopage_tlbl(&l, p);
        i_j(&p, (unsigned long)tlb_do_page_fault_0 & 0x0fffffff);
        i_nop(&p);

        if ((p - handle_tlbl) > FASTPATH_SIZE)
                panic("TLB load handler fastpath space exceeded");

        resolve_relocs(relocs, labels);
        pr_info("Synthesized TLB load handler fastpath (%u instructions).\n",
                (unsigned int)(p - handle_tlbl));

        pr_debug("\t.set push\n");
        pr_debug("\t.set noreorder\n");
        for (i = 0; i < (p - handle_tlbl); i++)
                pr_debug("\t.word 0x%08x\n", handle_tlbl[i]);
        pr_debug("\t.set pop\n");
}

static void __init build_r3000_tlb_store_handler(void)
{
        u32 *p = handle_tlbs;
        struct label *l = labels;
        struct reloc *r = relocs;
        int i;

        memset(handle_tlbs, 0, sizeof(handle_tlbs));
        memset(labels, 0, sizeof(labels));
        memset(relocs, 0, sizeof(relocs));

        build_r3000_tlbchange_handler_head(&p, K0, K1);
        build_pte_writable(&p, &l, &r, K0, K1, label_nopage_tlbs);
        i_nop(&p); /* load delay */
        build_make_write(&p, &r, K0, K1);
        build_r3000_tlb_reload_write(&p, &l, &r, K0, K1);

        l_nopage_tlbs(&l, p);
        i_j(&p, (unsigned long)tlb_do_page_fault_1 & 0x0fffffff);
        i_nop(&p);

        if ((p - handle_tlbs) > FASTPATH_SIZE)
                panic("TLB store handler fastpath space exceeded");

        resolve_relocs(relocs, labels);
        pr_info("Synthesized TLB store handler fastpath (%u instructions).\n",
                (unsigned int)(p - handle_tlbs));

        pr_debug("\t.set push\n");
        pr_debug("\t.set noreorder\n");
        for (i = 0; i < (p - handle_tlbs); i++)
                pr_debug("\t.word 0x%08x\n", handle_tlbs[i]);
        pr_debug("\t.set pop\n");
}

static void __init build_r3000_tlb_modify_handler(void)
{
        u32 *p = handle_tlbm;
        struct label *l = labels;
        struct reloc *r = relocs;
        int i;

        memset(handle_tlbm, 0, sizeof(handle_tlbm));
        memset(labels, 0, sizeof(labels));
        memset(relocs, 0, sizeof(relocs));

        build_r3000_tlbchange_handler_head(&p, K0, K1);
        build_pte_modifiable(&p, &l, &r, K0, K1, label_nopage_tlbm);
        i_nop(&p); /* load delay */
        build_make_write(&p, &r, K0, K1);
        build_r3000_pte_reload_tlbwi(&p, K0, K1);

        l_nopage_tlbm(&l, p);
        i_j(&p, (unsigned long)tlb_do_page_fault_1 & 0x0fffffff);
        i_nop(&p);

        if ((p - handle_tlbm) > FASTPATH_SIZE)
                panic("TLB modify handler fastpath space exceeded");

        resolve_relocs(relocs, labels);
        pr_info("Synthesized TLB modify handler fastpath (%u instructions).\n",
                (unsigned int)(p - handle_tlbm));

        pr_debug("\t.set push\n");
        pr_debug("\t.set noreorder\n");
        for (i = 0; i < (p - handle_tlbm); i++)
                pr_debug("\t.word 0x%08x\n", handle_tlbm[i]);
        pr_debug("\t.set pop\n");
}

/*
 * R4000 style TLB load/store/modify handlers.
 */
static void __init
build_r4000_tlbchange_handler_head(u32 **p, struct label **l,
                                   struct reloc **r, unsigned int pte,
                                   unsigned int ptr)
{
#ifdef CONFIG_64BIT
        build_get_pmde64(p, l, r, pte, ptr); /* get pmd in ptr */
#else
        build_get_pgde32(p, pte, ptr); /* get pgd in ptr */
#endif

        i_MFC0(p, pte, C0_BADVADDR);
        i_LW(p, ptr, 0, ptr);
        i_SRL(p, pte, pte, PAGE_SHIFT + PTE_ORDER - PTE_T_LOG2);
        i_andi(p, pte, pte, (PTRS_PER_PTE - 1) << PTE_T_LOG2);
        i_ADDU(p, ptr, ptr, pte);

#ifdef CONFIG_SMP
        l_smp_pgtable_change(l, *p);
# endif
        iPTE_LW(p, l, pte, ptr); /* get even pte */
        build_tlb_probe_entry(p);
}

static void __init
build_r4000_tlbchange_handler_tail(u32 **p, struct label **l,
                                   struct reloc **r, unsigned int tmp,
                                   unsigned int ptr)
{
        i_ori(p, ptr, ptr, sizeof(pte_t));
        i_xori(p, ptr, ptr, sizeof(pte_t));
        build_update_entries(p, tmp, ptr);
        build_tlb_write_entry(p, l, r, tlb_indexed);
        l_leave(l, *p);
        i_eret(p); /* return from trap */

#ifdef CONFIG_64BIT
        build_get_pgd_vmalloc64(p, l, r, tmp, ptr);
#endif
}

static void __init build_r4000_tlb_load_handler(void)
{
        u32 *p = handle_tlbl;
        struct label *l = labels;
        struct reloc *r = relocs;
        int i;

        memset(handle_tlbl, 0, sizeof(handle_tlbl));
        memset(labels, 0, sizeof(labels));
        memset(relocs, 0, sizeof(relocs));

        if (bcm1250_m3_war()) {
                i_MFC0(&p, K0, C0_BADVADDR);
                i_MFC0(&p, K1, C0_ENTRYHI);
                i_xor(&p, K0, K0, K1);
                i_SRL(&p, K0, K0, PAGE_SHIFT + 1);
                il_bnez(&p, &r, K0, label_leave);
                /* No need for i_nop */
        }

        build_r4000_tlbchange_handler_head(&p, &l, &r, K0, K1);
        build_pte_present(&p, &l, &r, K0, K1, label_nopage_tlbl);
        build_make_valid(&p, &r, K0, K1);
        build_r4000_tlbchange_handler_tail(&p, &l, &r, K0, K1);

        l_nopage_tlbl(&l, p);
        i_j(&p, (unsigned long)tlb_do_page_fault_0 & 0x0fffffff);
        i_nop(&p);

        if ((p - handle_tlbl) > FASTPATH_SIZE)
                panic("TLB load handler fastpath space exceeded");

        resolve_relocs(relocs, labels);
        pr_info("Synthesized TLB load handler fastpath (%u instructions).\n",
                (unsigned int)(p - handle_tlbl));

        pr_debug("\t.set push\n");
        pr_debug("\t.set noreorder\n");
        for (i = 0; i < (p - handle_tlbl); i++)
                pr_debug("\t.word 0x%08x\n", handle_tlbl[i]);
        pr_debug("\t.set pop\n");
}

static void __init build_r4000_tlb_store_handler(void)
{
        u32 *p = handle_tlbs;
        struct label *l = labels;
        struct reloc *r = relocs;
        int i;

        memset(handle_tlbs, 0, sizeof(handle_tlbs));
        memset(labels, 0, sizeof(labels));
        memset(relocs, 0, sizeof(relocs));

        build_r4000_tlbchange_handler_head(&p, &l, &r, K0, K1);
        build_pte_writable(&p, &l, &r, K0, K1, label_nopage_tlbs);
        build_make_write(&p, &r, K0, K1);
        build_r4000_tlbchange_handler_tail(&p, &l, &r, K0, K1);

        l_nopage_tlbs(&l, p);
        i_j(&p, (unsigned long)tlb_do_page_fault_1 & 0x0fffffff);
        i_nop(&p);

        if ((p - handle_tlbs) > FASTPATH_SIZE)
                panic("TLB store handler fastpath space exceeded");

        resolve_relocs(relocs, labels);
        pr_info("Synthesized TLB store handler fastpath (%u instructions).\n",
                (unsigned int)(p - handle_tlbs));

        pr_debug("\t.set push\n");
        pr_debug("\t.set noreorder\n");
        for (i = 0; i < (p - handle_tlbs); i++)
                pr_debug("\t.word 0x%08x\n", handle_tlbs[i]);
        pr_debug("\t.set pop\n");
}

static void __init build_r4000_tlb_modify_handler(void)
{
        u32 *p = handle_tlbm;
        struct label *l = labels;
        struct reloc *r = relocs;
        int i;

        memset(handle_tlbm, 0, sizeof(handle_tlbm));
        memset(labels, 0, sizeof(labels));
        memset(relocs, 0, sizeof(relocs));

        build_r4000_tlbchange_handler_head(&p, &l, &r, K0, K1);
        build_pte_modifiable(&p, &l, &r, K0, K1, label_nopage_tlbm);
        /* Present and writable bits set, set accessed and dirty bits. */
        build_make_write(&p, &r, K0, K1);
        build_r4000_tlbchange_handler_tail(&p, &l, &r, K0, K1);

        l_nopage_tlbm(&l, p);
        i_j(&p, (unsigned long)tlb_do_page_fault_1 & 0x0fffffff);
        i_nop(&p);

        if ((p - handle_tlbm) > FASTPATH_SIZE)
                panic("TLB modify handler fastpath space exceeded");

        resolve_relocs(relocs, labels);
        pr_info("Synthesized TLB modify handler fastpath (%u instructions).\n",
                (unsigned int)(p - handle_tlbm));

        pr_debug("\t.set push\n");
        pr_debug("\t.set noreorder\n");
        for (i = 0; i < (p - handle_tlbm); i++)
                pr_debug("\t.word 0x%08x\n", handle_tlbm[i]);
        pr_debug("\t.set pop\n");
}

void __init build_tlb_refill_handler(void)
{
        /*
         * The refill handler is generated per-CPU, multi-node systems
         * may have local storage for it. The other handlers are only
         * needed once.
         */
        static int run_once = 0;

        switch (current_cpu_data.cputype) {
        case CPU_R2000:
        case CPU_R3000:
        case CPU_R3000A:
        case CPU_R3081E:
        case CPU_TX3912:
        case CPU_TX3922:
        case CPU_TX3927:
                build_r3000_tlb_refill_handler();
                if (!run_once) {
                        build_r3000_tlb_load_handler();
                        build_r3000_tlb_store_handler();
                        build_r3000_tlb_modify_handler();
                        run_once++;
                }
                break;

        case CPU_R6000:
        case CPU_R6000A:
                panic("No R6000 TLB refill handler yet");
                break;

        case CPU_R8000:
                panic("No R8000 TLB refill handler yet");
                break;

        default:
                build_r4000_tlb_refill_handler();
                if (!run_once) {
                        build_r4000_tlb_load_handler();
                        build_r4000_tlb_store_handler();
                        build_r4000_tlb_modify_handler();
                        run_once++;
                }
        }
}

void __init flush_tlb_handlers(void)
{
        flush_icache_range((unsigned long)handle_tlbl,
                           (unsigned long)handle_tlbl + sizeof(handle_tlbl));
        flush_icache_range((unsigned long)handle_tlbs,
                           (unsigned long)handle_tlbs + sizeof(handle_tlbs));
        flush_icache_range((unsigned long)handle_tlbm,
                           (unsigned long)handle_tlbm + sizeof(handle_tlbm));
}