Archipelago » qemu

/*

 *  qemu user main

 *

 *  Copyright (c) 2003 Fabrice Bellard

 *  Copyright (c) 2006 Pierre d'Herbemont

 *

 *  This program is free software; you can redistribute it and/or modify

 *  it under the terms of the GNU General Public License as published by

 *  the Free Software Foundation; either version 2 of the License, or

 *  (at your option) any later version.

 *

 *  This program is distributed in the hope that it will be useful,

 *  but WITHOUT ANY WARRANTY; without even the implied warranty of

 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 *  GNU General Public License for more details.

 *

 *  You should have received a copy of the GNU General Public License

 *  along with this program; if not, write to the Free Software

 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

 */

#include <stdlib.h>

#include <stdio.h>

#include <stdarg.h>

#include <string.h>

#include <errno.h>

#include <unistd.h>

#include <sys/syscall.h>

#include <sys/mman.h>

#include "qemu.h"

#define DEBUG_LOGFILE "/tmp/qemu.log"

#ifdef __APPLE__

#include <crt_externs.h>

# define environ  (*_NSGetEnviron())

#endif

#include <mach/mach_init.h>

#include <mach/vm_map.h>

const char *interp_prefix = "";

asm(".zerofill __STD_PROG_ZONE, __STD_PROG_ZONE, __std_prog_zone, 0x0dfff000");

/* XXX: on x86 MAP_GROWSDOWN only works if ESP <= address + 32, so

   we allocate a bigger stack. Need a better solution, for example

   by remapping the process stack directly at the right place */

unsigned long stack_size = 512 * 1024;

void qerror(const char *fmt, ...)

{

    va_list ap;

    va_start(ap, fmt);

    vfprintf(stderr, fmt, ap);

    va_end(ap);

    fprintf(stderr, "\n");

    exit(1);

}

void gemu_log(const char *fmt, ...)

{

    va_list ap;

    va_start(ap, fmt);

    vfprintf(stderr, fmt, ap);

    va_end(ap);

}

void cpu_outb(CPUState *env, int addr, int val)

{

    fprintf(stderr, "outb: port=0x%04x, data=%02x\n", addr, val);

}

void cpu_outw(CPUState *env, int addr, int val)

{

    fprintf(stderr, "outw: port=0x%04x, data=%04x\n", addr, val);

}

void cpu_outl(CPUState *env, int addr, int val)

{

    fprintf(stderr, "outl: port=0x%04x, data=%08x\n", addr, val);

}

int cpu_inb(CPUState *env, int addr)

{

    fprintf(stderr, "inb: port=0x%04x\n", addr);

    return 0;

}

int cpu_inw(CPUState *env, int addr)

{

    fprintf(stderr, "inw: port=0x%04x\n", addr);

    return 0;

}

int cpu_inl(CPUState *env, int addr)

{

    fprintf(stderr, "inl: port=0x%04x\n", addr);

    return 0;

}

int cpu_get_pic_interrupt(CPUState *env)

{

    return -1;

}

#ifdef TARGET_PPC

static inline uint64_t cpu_ppc_get_tb (CPUState *env)

{

    /* TO FIX */

    return 0;

}

uint32_t cpu_ppc_load_tbl (CPUState *env)

{

    return cpu_ppc_get_tb(env) & 0xFFFFFFFF;

}

uint32_t cpu_ppc_load_tbu (CPUState *env)

{

    return cpu_ppc_get_tb(env) >> 32;

}

static void cpu_ppc_store_tb (CPUState *env, uint64_t value)

{

    /* TO FIX */

}

void cpu_ppc_store_tbu (CPUState *env, uint32_t value)

{

    cpu_ppc_store_tb(env, ((uint64_t)value << 32) | cpu_ppc_load_tbl(env));

}

void cpu_ppc_store_tbl (CPUState *env, uint32_t value)

{

    cpu_ppc_store_tb(env, ((uint64_t)cpu_ppc_load_tbl(env) << 32) | value);

}

uint32_t cpu_ppc_load_decr (CPUState *env)

{

    /* TO FIX */

    return -1;

}

void cpu_ppc_store_decr (CPUState *env, uint32_t value)

{

    /* TO FIX */

}

void cpu_loop(CPUPPCState *env)

{

    int trapnr;

    uint32_t ret;

    target_siginfo_t info;

    for(;;) {

        trapnr = cpu_ppc_exec(env);

        if (trapnr != EXCP_SYSCALL_USER && trapnr != EXCP_BRANCH &&

            trapnr != EXCP_TRACE) {

            if (loglevel > 0) {

                cpu_dump_state(env, logfile, fprintf, 0);

            }

        }

        switch(trapnr) {

        case EXCP_NONE:

            break;

        case EXCP_SYSCALL_USER:

            /* system call */

            if(((int)env->gpr[0]) <= SYS_MAXSYSCALL && ((int)env->gpr[0])>0)

                ret = do_unix_syscall(env, env->gpr[0]/*, env->gpr[3], env->gpr[4],

                                      env->gpr[5], env->gpr[6], env->gpr[7],

                                      env->gpr[8], env->gpr[9], env->gpr[10]*/);

            else if(((int)env->gpr[0])<0)

                ret = do_mach_syscall(env, env->gpr[0], env->gpr[3], env->gpr[4],

                                      env->gpr[5], env->gpr[6], env->gpr[7],

                                      env->gpr[8], env->gpr[9], env->gpr[10]);

            else

                ret = do_thread_syscall(env, env->gpr[0], env->gpr[3], env->gpr[4],

                                        env->gpr[5], env->gpr[6], env->gpr[7],

                                        env->gpr[8], env->gpr[9], env->gpr[10]);

            /* Unix syscall error signaling */

            if(((int)env->gpr[0]) <= SYS_MAXSYSCALL && ((int)env->gpr[0])>0)

            {

                if( (int)ret < 0 )

                    env->nip += 0;

                else

                    env->nip += 4;

            }

            /* Return value */

            env->gpr[3] = ret;

            break;

        case EXCP_RESET:

            /* Should not happen ! */

            fprintf(stderr, "RESET asked... Stop emulation\n");

            if (loglevel)

                fprintf(logfile, "RESET asked... Stop emulation\n");

                abort();

        case EXCP_MACHINE_CHECK:

            fprintf(stderr, "Machine check exeption...  Stop emulation\n");

            if (loglevel)

                fprintf(logfile, "RESET asked... Stop emulation\n");

                info.si_signo = SIGBUS;

            info.si_errno = 0;

            info.si_code = BUS_OBJERR;

            info.si_addr = (void*)(env->nip - 4);

            queue_signal(info.si_signo, &info);

        case EXCP_DSI:

#ifndef DAR

/* To deal with multiple qemu header version as host for the darwin-user code */

# define DAR SPR_DAR

#endif

            fprintf(stderr, "Invalid data memory access: 0x%08x\n", env->spr[DAR]);

            if (loglevel) {

                fprintf(logfile, "Invalid data memory access: 0x%08x\n",

                        env->spr[DAR]);

            }

            /* Handle this via the gdb */

            gdb_handlesig (env, SIGSEGV);

            info.si_addr = (void*)env->nip;

            queue_signal(info.si_signo, &info);

            break;

        case EXCP_ISI:

            fprintf(stderr, "Invalid instruction fetch\n");

            if (loglevel)

                fprintf(logfile, "Invalid instruction fetch\n");

            /* Handle this via the gdb */

            gdb_handlesig (env, SIGSEGV);

            info.si_addr = (void*)(env->nip - 4);

            queue_signal(info.si_signo, &info);

            break;

        case EXCP_EXTERNAL:

            /* Should not happen ! */

            fprintf(stderr, "External interruption... Stop emulation\n");

            if (loglevel)

                fprintf(logfile, "External interruption... Stop emulation\n");

                abort();

        case EXCP_ALIGN:

            fprintf(stderr, "Invalid unaligned memory access\n");

            if (loglevel)

                fprintf(logfile, "Invalid unaligned memory access\n");

                info.si_signo = SIGBUS;

            info.si_errno = 0;

            info.si_code = BUS_ADRALN;

            info.si_addr = (void*)(env->nip - 4);

            queue_signal(info.si_signo, &info);

            break;

        case EXCP_PROGRAM:

            switch (env->error_code & ~0xF) {

                case EXCP_FP:

                    fprintf(stderr, "Program exception\n");

                    if (loglevel)

                        fprintf(logfile, "Program exception\n");

                        /* Set FX */

                        env->fpscr[7] |= 0x8;

                    /* Finally, update FEX */

                    if ((((env->fpscr[7] & 0x3) << 3) | (env->fpscr[6] >> 1)) &

                        ((env->fpscr[1] << 1) | (env->fpscr[0] >> 3)))

                        env->fpscr[7] |= 0x4;

                        info.si_signo = SIGFPE;

                    info.si_errno = 0;

                    switch (env->error_code & 0xF) {

                        case EXCP_FP_OX:

                            info.si_code = FPE_FLTOVF;

                            break;

                        case EXCP_FP_UX:

                            info.si_code = FPE_FLTUND;

                            break;

                        case EXCP_FP_ZX:

                        case EXCP_FP_VXZDZ:

                            info.si_code = FPE_FLTDIV;

                            break;

                        case EXCP_FP_XX:

                            info.si_code = FPE_FLTRES;

                            break;

                        case EXCP_FP_VXSOFT:

                            info.si_code = FPE_FLTINV;

                            break;

                        case EXCP_FP_VXNAN:

                        case EXCP_FP_VXISI:

                        case EXCP_FP_VXIDI:

                        case EXCP_FP_VXIMZ:

                        case EXCP_FP_VXVC:

                        case EXCP_FP_VXSQRT:

                        case EXCP_FP_VXCVI:

                            info.si_code = FPE_FLTSUB;

                            break;

                        default:

                            fprintf(stderr, "Unknown floating point exception "

                                    "(%02x)\n", env->error_code);

                            if (loglevel) {

                                fprintf(logfile, "Unknown floating point exception "

                                        "(%02x)\n", env->error_code & 0xF);

                            }

                    }

                        break;

                case EXCP_INVAL:

                    fprintf(stderr, "Invalid instruction\n");

                    if (loglevel)

                        fprintf(logfile, "Invalid instruction\n");

                        info.si_signo = SIGILL;

                    info.si_errno = 0;

                    switch (env->error_code & 0xF) {

                        case EXCP_INVAL_INVAL:

                            info.si_code = ILL_ILLOPC;

                            break;

                        case EXCP_INVAL_LSWX:

                            info.si_code = ILL_ILLOPN;

                            break;

                        case EXCP_INVAL_SPR:

                            info.si_code = ILL_PRVREG;

                            break;

                        case EXCP_INVAL_FP:

                            info.si_code = ILL_COPROC;

                            break;

                        default:

                            fprintf(stderr, "Unknown invalid operation (%02x)\n",

                                    env->error_code & 0xF);

                            if (loglevel) {

                                fprintf(logfile, "Unknown invalid operation (%02x)\n",

                                        env->error_code & 0xF);

                            }

                                info.si_code = ILL_ILLADR;

                            break;

                    }

                        /* Handle this via the gdb */

                        gdb_handlesig (env, SIGSEGV);

                    break;

                case EXCP_PRIV:

                    fprintf(stderr, "Privilege violation\n");

                    if (loglevel)

                        fprintf(logfile, "Privilege violation\n");

                        info.si_signo = SIGILL;

                    info.si_errno = 0;

                    switch (env->error_code & 0xF) {

                        case EXCP_PRIV_OPC:

                            info.si_code = ILL_PRVOPC;

                            break;

                        case EXCP_PRIV_REG:

                            info.si_code = ILL_PRVREG;

                            break;

                        default:

                            fprintf(stderr, "Unknown privilege violation (%02x)\n",

                                    env->error_code & 0xF);

                            info.si_code = ILL_PRVOPC;

                            break;

                    }

                        break;

                case EXCP_TRAP:

                    fprintf(stderr, "Tried to call a TRAP\n");

                    if (loglevel)

                        fprintf(logfile, "Tried to call a TRAP\n");

                        abort();

                default:

                    /* Should not happen ! */

                    fprintf(stderr, "Unknown program exception (%02x)\n",

                            env->error_code);

                    if (loglevel) {

                        fprintf(logfile, "Unknwon program exception (%02x)\n",

                                env->error_code);

                    }

                        abort();

            }

            info.si_addr = (void*)(env->nip - 4);

            queue_signal(info.si_signo, &info);

            break;

        case EXCP_NO_FP:

            fprintf(stderr, "No floating point allowed\n");

            if (loglevel)

                fprintf(logfile, "No floating point allowed\n");

                info.si_signo = SIGILL;

            info.si_errno = 0;

            info.si_code = ILL_COPROC;

            info.si_addr = (void*)(env->nip - 4);

            queue_signal(info.si_signo, &info);

            break;

        case EXCP_DECR:

            /* Should not happen ! */

            fprintf(stderr, "Decrementer exception\n");

            if (loglevel)

                fprintf(logfile, "Decrementer exception\n");

            abort();

        case EXCP_TRACE:

            /* Pass to gdb: we use this to trace execution */

            gdb_handlesig (env, SIGTRAP);

            break;

        case EXCP_FP_ASSIST:

            /* Should not happen ! */

            fprintf(stderr, "Floating point assist exception\n");

            if (loglevel)

                fprintf(logfile, "Floating point assist exception\n");

            abort();

        case EXCP_MTMSR:

            /* We reloaded the msr, just go on */

            if (msr_pr == 0) {

                fprintf(stderr, "Tried to go into supervisor mode !\n");

                if (loglevel)

                    fprintf(logfile, "Tried to go into supervisor mode !\n");

                abort();

            }

            break;

        case EXCP_BRANCH:

            /* We stopped because of a jump... */

            break;

        case EXCP_INTERRUPT:

            /* Don't know why this should ever happen... */

            fprintf(stderr, "EXCP_INTERRUPT\n");

            break;

        case EXCP_DEBUG:

            gdb_handlesig (env, SIGTRAP);

            break;

        default:

            fprintf(stderr, "qemu: unhandled CPU exception 0x%x - aborting\n",

                    trapnr);

            if (loglevel) {

                fprintf(logfile, "qemu: unhandled CPU exception 0x%02x - "

                        "0x%02x - aborting\n", trapnr, env->error_code);

            }

                abort();

        }

        process_pending_signals(env);

    }

}

#endif

#ifdef TARGET_I386

/***********************************************************/

/* CPUX86 core interface */

uint64_t cpu_get_tsc(CPUX86State *env)

{

    return cpu_get_real_ticks();

}

void

write_dt(void *ptr, unsigned long addr, unsigned long limit,

                     int flags)

{

    unsigned int e1, e2;

    e1 = (addr << 16) | (limit & 0xffff);

    e2 = ((addr >> 16) & 0xff) | (addr & 0xff000000) | (limit & 0x000f0000);

    e2 |= flags;

    stl((uint8_t *)ptr, e1);

    stl((uint8_t *)ptr + 4, e2);

}

static void set_gate(void *ptr, unsigned int type, unsigned int dpl,

                     unsigned long addr, unsigned int sel)

{

    unsigned int e1, e2;

    e1 = (addr & 0xffff) | (sel << 16);

    e2 = (addr & 0xffff0000) | 0x8000 | (dpl << 13) | (type << 8);

    stl((uint8_t *)ptr, e1);

    stl((uint8_t *)ptr + 4, e2);

}

#define GDT_TABLE_SIZE 14

#define LDT_TABLE_SIZE 15

#define IDT_TABLE_SIZE 256

#define TSS_SIZE 104

uint64_t gdt_table[GDT_TABLE_SIZE];

uint64_t ldt_table[LDT_TABLE_SIZE];

uint64_t idt_table[IDT_TABLE_SIZE];

uint32_t tss[TSS_SIZE];

/* only dpl matters as we do only user space emulation */

static void set_idt(int n, unsigned int dpl)

{

    set_gate(idt_table + n, 0, dpl, 0, 0);

}

/* ABI convention: after a syscall if there was an error the CF flag is set */

static inline void set_error(CPUX86State *env, int ret)

{

    if(ret<0)

        env->eflags = env->eflags | 0x1;

    else

        env->eflags &= ~0x1;

    env->regs[R_EAX] = ret;

}

void cpu_loop(CPUX86State *env)

{

    int trapnr;

    int ret;

    uint8_t *pc;

    target_siginfo_t info;

    for(;;) {

        trapnr = cpu_x86_exec(env);

        uint32_t *params = (uint32_t *)env->regs[R_ESP];

        switch(trapnr) {

        case 0x79: /* Our commpage hack back door exit is here */

            do_commpage(env,  env->eip,   *(params + 1), *(params + 2),

                                          *(params + 3), *(params + 4),

                                          *(params + 5), *(params + 6),

                                          *(params + 7), *(params + 8));

            break;

        case 0x81: /* mach syscall */

        {

            ret = do_mach_syscall(env,  env->regs[R_EAX],

                                          *(params + 1), *(params + 2),

                                          *(params + 3), *(params + 4),

                                          *(params + 5), *(params + 6),

                                          *(params + 7), *(params + 8));

            set_error(env, ret);

            break;

        }

        case 0x90: /* unix backdoor */

        {

            /* after sysenter, stack is in R_ECX, new eip in R_EDX (sysexit will flip them back)*/

            int saved_stack = env->regs[R_ESP];

            env->regs[R_ESP] = env->regs[R_ECX];

            ret = do_unix_syscall(env, env->regs[R_EAX]);

            env->regs[R_ECX] = env->regs[R_ESP];

            env->regs[R_ESP] = saved_stack;

            set_error(env, ret);

            break;

        }

        case 0x80: /* unix syscall */

        {

            ret = do_unix_syscall(env, env->regs[R_EAX]/*,

                                          *(params + 1), *(params + 2),

                                          *(params + 3), *(params + 4),

                                          *(params + 5), *(params + 6),

                                          *(params + 7), *(params + 8)*/);

            set_error(env, ret);

            break;

        }

        case 0x82: /* thread syscall */

        {

            ret = do_thread_syscall(env,  env->regs[R_EAX],

                                          *(params + 1), *(params + 2),

                                          *(params + 3), *(params + 4),

                                          *(params + 5), *(params + 6),

                                          *(params + 7), *(params + 8));

            set_error(env, ret);

            break;

        }

        case EXCP0B_NOSEG:

        case EXCP0C_STACK:

            info.si_signo = SIGBUS;

            info.si_errno = 0;

            info.si_code = BUS_NOOP;

            info.si_addr = 0;

            gdb_handlesig (env, SIGBUS);

            queue_signal(info.si_signo, &info);

            break;

        case EXCP0D_GPF:

            info.si_signo = SIGSEGV;

            info.si_errno = 0;

            info.si_code = SEGV_NOOP;

            info.si_addr = 0;

            gdb_handlesig (env, SIGSEGV);

            queue_signal(info.si_signo, &info);

            break;

        case EXCP0E_PAGE:

            info.si_signo = SIGSEGV;

            info.si_errno = 0;

            if (!(env->error_code & 1))

                info.si_code = SEGV_MAPERR;

            else

                info.si_code = SEGV_ACCERR;

            info.si_addr = (void*)env->cr[2];

            gdb_handlesig (env, SIGSEGV);

            queue_signal(info.si_signo, &info);

            break;

        case EXCP00_DIVZ:

            /* division by zero */

            info.si_signo = SIGFPE;

            info.si_errno = 0;

            info.si_code = FPE_INTDIV;

            info.si_addr = (void*)env->eip;

            gdb_handlesig (env, SIGFPE);

            queue_signal(info.si_signo, &info);

            break;

        case EXCP01_SSTP:

        case EXCP03_INT3:

            info.si_signo = SIGTRAP;

            info.si_errno = 0;

            info.si_code = TRAP_BRKPT;

            info.si_addr = (void*)env->eip;

            gdb_handlesig (env, SIGTRAP);

            queue_signal(info.si_signo, &info);

            break;

        case EXCP04_INTO:

        case EXCP05_BOUND:

            info.si_signo = SIGSEGV;

            info.si_errno = 0;

            info.si_code = SEGV_NOOP;

            info.si_addr = 0;

            gdb_handlesig (env, SIGSEGV);

            queue_signal(info.si_signo, &info);

            break;

        case EXCP06_ILLOP:

            info.si_signo = SIGILL;

            info.si_errno = 0;

            info.si_code = ILL_ILLOPN;

            info.si_addr = (void*)env->eip;

            gdb_handlesig (env, SIGILL);

            queue_signal(info.si_signo, &info);

            break;

        case EXCP_INTERRUPT:

            /* just indicate that signals should be handled asap */

            break;

        case EXCP_DEBUG:

            {

                int sig;

                sig = gdb_handlesig (env, SIGTRAP);

                if (sig)

                  {

                    info.si_signo = sig;

                    info.si_errno = 0;

                    info.si_code = TRAP_BRKPT;

                    queue_signal(info.si_signo, &info);

                  }

            }

            break;

        default:

            pc = (void*)(env->segs[R_CS].base + env->eip);

            fprintf(stderr, "qemu: 0x%08lx: unhandled CPU exception 0x%x - aborting\n",

                    (long)pc, trapnr);

            abort();

        }

        process_pending_signals(env);

    }

}

#endif

void usage(void)

{

    printf("qemu-" TARGET_ARCH " version " QEMU_VERSION ", Copyright (c) 2003-2004 Fabrice Bellard\n"

           "usage: qemu-" TARGET_ARCH " [-h] [-d opts] [-L path] [-s size] program [arguments...]\n"

           "Darwin CPU emulator (compiled for %s emulation)\n"

           "\n"

           "-h           print this help\n"

           "-L path      set the %s library path (default='%s')\n"

           "-s size      set the stack size in bytes (default=%ld)\n"

           "\n"

           "debug options:\n"

#ifdef USE_CODE_COPY

           "-no-code-copy   disable code copy acceleration\n"

#endif

           "-d options   activate log (logfile='%s')\n"

           "-g wait for gdb on port 1234\n"

           "-p pagesize  set the host page size to 'pagesize'\n",

           TARGET_ARCH,

           TARGET_ARCH,

           interp_prefix,

           stack_size,

           DEBUG_LOGFILE);

    _exit(1);

}

/* XXX: currently only used for async signals (see signal.c) */

CPUState *global_env;

/* used only if single thread */

CPUState *cpu_single_env = NULL;

/* used to free thread contexts */

TaskState *first_task_state;

int main(int argc, char **argv)

{

    const char *filename;

    struct target_pt_regs regs1, *regs = &regs1;

    TaskState ts1, *ts = &ts1;

    CPUState *env;

    int optind;

    short use_gdbstub = 0;

    const char *r;

    if (argc <= 1)

        usage();

    /* init debug */

    cpu_set_log_filename(DEBUG_LOGFILE);

    optind = 1;

    for(;;) {

        if (optind >= argc)

            break;

        r = argv[optind];

        if (r[0] != '-')

            break;

        optind++;

        r++;

        if (!strcmp(r, "-")) {

            break;

        } else if (!strcmp(r, "d")) {

            int mask;

            CPULogItem *item;

        if (optind >= argc)

        break;

        r = argv[optind++];

            mask = cpu_str_to_log_mask(r);

            if (!mask) {

                printf("Log items (comma separated):\n");

                for(item = cpu_log_items; item->mask != 0; item++) {

                    printf("%-10s %s\n", item->name, item->help);

                }

                exit(1);

            }

            cpu_set_log(mask);

        } else if (!strcmp(r, "s")) {

            r = argv[optind++];

            stack_size = strtol(r, (char **)&r, 0);

            if (stack_size <= 0)

                usage();

            if (*r == 'M')

                stack_size *= 1024 * 1024;

            else if (*r == 'k' || *r == 'K')

                stack_size *= 1024;

        } else if (!strcmp(r, "L")) {

            interp_prefix = argv[optind++];

        } else if (!strcmp(r, "p")) {

            qemu_host_page_size = atoi(argv[optind++]);

            if (qemu_host_page_size == 0 ||

                (qemu_host_page_size & (qemu_host_page_size - 1)) != 0) {

                fprintf(stderr, "page size must be a power of two\n");

                exit(1);

            }

        } else

        if (!strcmp(r, "g")) {

            use_gdbstub = 1;

        } else

#ifdef USE_CODE_COPY

        if (!strcmp(r, "no-code-copy")) {

            code_copy_enabled = 0;

        } else

#endif

        {

            usage();

        }

    }

    if (optind >= argc)

        usage();

    filename = argv[optind];

    /* Zero out regs */

    memset(regs, 0, sizeof(struct target_pt_regs));

    /* NOTE: we need to init the CPU at this stage to get

       qemu_host_page_size */

    env = cpu_init();

    printf("Starting %s with qemu\n----------------\n", filename);

    commpage_init();

    if (mach_exec(filename, argv+optind, environ, regs) != 0) {

    printf("Error loading %s\n", filename);

    _exit(1);

    }

    syscall_init();

    signal_init();

    global_env = env;

    /* build Task State */

    memset(ts, 0, sizeof(TaskState));

    env->opaque = ts;

    ts->used = 1;

    env->user_mode_only = 1;

#if defined(TARGET_I386)

    cpu_x86_set_cpl(env, 3);

    env->cr[0] = CR0_PG_MASK | CR0_WP_MASK | CR0_PE_MASK;

    env->hflags |= HF_PE_MASK;

    if (env->cpuid_features & CPUID_SSE) {

        env->cr[4] |= CR4_OSFXSR_MASK;

        env->hflags |= HF_OSFXSR_MASK;

    }

    /* flags setup : we activate the IRQs by default as in user mode */

    env->eflags |= IF_MASK;

    /* darwin register setup */

    env->regs[R_EAX] = regs->eax;

    env->regs[R_EBX] = regs->ebx;

    env->regs[R_ECX] = regs->ecx;

    env->regs[R_EDX] = regs->edx;

    env->regs[R_ESI] = regs->esi;

    env->regs[R_EDI] = regs->edi;

    env->regs[R_EBP] = regs->ebp;

    env->regs[R_ESP] = regs->esp;

    env->eip = regs->eip;

    /* Darwin LDT setup */

    /* 2 - User code segment

       3 - User data segment

       4 - User cthread */

    bzero(ldt_table, LDT_TABLE_SIZE * sizeof(ldt_table[0]));

    env->ldt.base = (uint32_t) ldt_table;

    env->ldt.limit = sizeof(ldt_table) - 1;

    write_dt(ldt_table + 2, 0, 0xfffff,

             DESC_G_MASK | DESC_B_MASK | DESC_P_MASK | DESC_S_MASK |

             (3 << DESC_DPL_SHIFT) | (0xa << DESC_TYPE_SHIFT));

    write_dt(ldt_table + 3, 0, 0xfffff,

             DESC_G_MASK | DESC_B_MASK | DESC_P_MASK | DESC_S_MASK |

             (3 << DESC_DPL_SHIFT) | (0x2 << DESC_TYPE_SHIFT));

    write_dt(ldt_table + 4, 0, 0xfffff,

             DESC_G_MASK | DESC_B_MASK | DESC_P_MASK | DESC_S_MASK |

             (3 << DESC_DPL_SHIFT) | (0x2 << DESC_TYPE_SHIFT));

    /* Darwin GDT setup.

     * has changed a lot between old Darwin/x86 (pre-Mac Intel) and Mac OS X/x86,

       now everything is done via  int 0x81(mach) int 0x82 (thread) and sysenter/sysexit(unix) */

    bzero(gdt_table, sizeof(gdt_table));

    env->gdt.base = (uint32_t)gdt_table;

    env->gdt.limit = sizeof(gdt_table) - 1;

    /* Set up a back door to handle sysenter syscalls (unix) */

    char * syscallbackdoor = malloc(64);

    page_set_flags((int)syscallbackdoor, (int)syscallbackdoor + 64, PROT_EXEC | PROT_READ | PAGE_VALID);

    int i = 0;

    syscallbackdoor[i++] = 0xcd;

    syscallbackdoor[i++] = 0x90; /* int 0x90 */

    syscallbackdoor[i++] = 0x0F;

    syscallbackdoor[i++] = 0x35; /* sysexit */

    /* Darwin sysenter/sysexit setup */

    env->sysenter_cs = 0x1; //XXX

    env->sysenter_eip = (int)syscallbackdoor;

    env->sysenter_esp = (int)malloc(64);

    /* Darwin TSS setup

       This must match up with GDT[4] */

    env->tr.base = (uint32_t) tss;

    env->tr.limit = sizeof(tss) - 1;

    env->tr.flags = DESC_P_MASK | (0x9 << DESC_TYPE_SHIFT);

    stw(tss + 2, 0x10);  // ss0 = 0x10 = GDT[2] = Kernel Data Segment

    /* Darwin interrupt setup */

    bzero(idt_table, sizeof(idt_table));

    env->idt.base = (uint32_t) idt_table;

    env->idt.limit = sizeof(idt_table) - 1;

    set_idt(0, 0);

    set_idt(1, 0);

    set_idt(2, 0);

    set_idt(3, 3);

    set_idt(4, 3);