Archipelago » qemu

/*

 *  qemu user main

 *

 *  Copyright (c) 2003-2008 Fabrice Bellard

 *

 *  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, see <http://www.gnu.org/licenses/>.

 */

#include <stdlib.h>

#include <stdio.h>

#include <stdarg.h>

#include <string.h>

#include <errno.h>

#include <unistd.h>

#include <machine/trap.h>

#include <sys/types.h>

#include <sys/mman.h>

#include "qemu.h"

#include "qemu-common.h"

/* For tb_lock */

#include "exec-all.h"

#include "tcg.h"

#include "qemu-timer.h"

#include "envlist.h"

#define DEBUG_LOGFILE "/tmp/qemu.log"

int singlestep;

#if defined(CONFIG_USE_GUEST_BASE)

unsigned long mmap_min_addr;

unsigned long guest_base;

int have_guest_base;

#endif

static const char *interp_prefix = CONFIG_QEMU_INTERP_PREFIX;

const char *qemu_uname_release = CONFIG_UNAME_RELEASE;

extern char **environ;

enum BSDType bsd_type;

/* 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 x86_stack_size = 512 * 1024;

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

{

    va_list ap;

    va_start(ap, fmt);

    vfprintf(stderr, fmt, ap);

    va_end(ap);

}

#if defined(TARGET_I386)

int cpu_get_pic_interrupt(CPUState *env)

{

    return -1;

}

#endif

/* These are no-ops because we are not threadsafe.  */

static inline void cpu_exec_start(CPUState *env)

{

}

static inline void cpu_exec_end(CPUState *env)

{

}

static inline void start_exclusive(void)

{

}

static inline void end_exclusive(void)

{

}

void fork_start(void)

{

}

void fork_end(int child)

{

    if (child) {

        gdbserver_fork(thread_env);

    }

}

void cpu_list_lock(void)

{

}

void cpu_list_unlock(void)

{

}

#ifdef TARGET_I386

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

/* CPUX86 core interface */

void cpu_smm_update(CPUState *env)

{

}

uint64_t cpu_get_tsc(CPUX86State *env)

{

    return cpu_get_real_ticks();

}

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

                     int flags)

{

    unsigned int e1, e2;

    uint32_t *p;

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

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

    e2 |= flags;

    p = ptr;

    p[0] = tswap32(e1);

    p[1] = tswap32(e2);

}

static uint64_t *idt_table;

#ifdef TARGET_X86_64

static void set_gate64(void *ptr, unsigned int type, unsigned int dpl,

                       uint64_t addr, unsigned int sel)

{

    uint32_t *p, e1, e2;

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

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

    p = ptr;

    p[0] = tswap32(e1);

    p[1] = tswap32(e2);

    p[2] = tswap32(addr >> 32);

    p[3] = 0;

}

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

static void set_idt(int n, unsigned int dpl)

{

    set_gate64(idt_table + n * 2, 0, dpl, 0, 0);

}

#else

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

                     uint32_t addr, unsigned int sel)

{

    uint32_t *p, e1, e2;

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

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

    p = ptr;

    p[0] = tswap32(e1);

    p[1] = tswap32(e2);

}

/* 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);

}

#endif

void cpu_loop(CPUX86State *env)

{

    int trapnr;

    abi_ulong pc;

    //target_siginfo_t info;

    for(;;) {

        trapnr = cpu_x86_exec(env);

        switch(trapnr) {

        case 0x80:

            /* syscall from int $0x80 */

            if (bsd_type == target_freebsd) {

                abi_ulong params = (abi_ulong) env->regs[R_ESP] +

                    sizeof(int32_t);

                int32_t syscall_nr = env->regs[R_EAX];

                int32_t arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8;

                if (syscall_nr == TARGET_FREEBSD_NR_syscall) {

                    get_user_s32(syscall_nr, params);

                    params += sizeof(int32_t);

                } else if (syscall_nr == TARGET_FREEBSD_NR___syscall) {

                    get_user_s32(syscall_nr, params);

                    params += sizeof(int64_t);

                }

                get_user_s32(arg1, params);

                params += sizeof(int32_t);

                get_user_s32(arg2, params);

                params += sizeof(int32_t);

                get_user_s32(arg3, params);

                params += sizeof(int32_t);

                get_user_s32(arg4, params);

                params += sizeof(int32_t);

                get_user_s32(arg5, params);

                params += sizeof(int32_t);

                get_user_s32(arg6, params);

                params += sizeof(int32_t);

                get_user_s32(arg7, params);

                params += sizeof(int32_t);

                get_user_s32(arg8, params);

                env->regs[R_EAX] = do_freebsd_syscall(env,

                                                      syscall_nr,

                                                      arg1,

                                                      arg2,

                                                      arg3,

                                                      arg4,

                                                      arg5,

                                                      arg6,

                                                      arg7,

                                                      arg8);

            } else { //if (bsd_type == target_openbsd)

                env->regs[R_EAX] = do_openbsd_syscall(env,

                                                      env->regs[R_EAX],

                                                      env->regs[R_EBX],

                                                      env->regs[R_ECX],

                                                      env->regs[R_EDX],

                                                      env->regs[R_ESI],

                                                      env->regs[R_EDI],

                                                      env->regs[R_EBP]);

            }

            if (((abi_ulong)env->regs[R_EAX]) >= (abi_ulong)(-515)) {

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

                env->eflags |= CC_C;

            } else {

                env->eflags &= ~CC_C;

            }

            break;

#ifndef TARGET_ABI32

        case EXCP_SYSCALL:

            /* syscall from syscall intruction */

            if (bsd_type == target_freebsd)

                env->regs[R_EAX] = do_freebsd_syscall(env,

                                                      env->regs[R_EAX],

                                                      env->regs[R_EDI],

                                                      env->regs[R_ESI],

                                                      env->regs[R_EDX],

                                                      env->regs[R_ECX],

                                                      env->regs[8],

                                                      env->regs[9], 0, 0);

            else { //if (bsd_type == target_openbsd)

                env->regs[R_EAX] = do_openbsd_syscall(env,

                                                      env->regs[R_EAX],

                                                      env->regs[R_EDI],

                                                      env->regs[R_ESI],

                                                      env->regs[R_EDX],

                                                      env->regs[10],

                                                      env->regs[8],

                                                      env->regs[9]);

            }

            env->eip = env->exception_next_eip;

            if (((abi_ulong)env->regs[R_EAX]) >= (abi_ulong)(-515)) {

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

                env->eflags |= CC_C;

            } else {

                env->eflags &= ~CC_C;

            }

            break;

#endif

#if 0

        case EXCP0B_NOSEG:

        case EXCP0C_STACK:

            info.si_signo = SIGBUS;

            info.si_errno = 0;

            info.si_code = TARGET_SI_KERNEL;

            info._sifields._sigfault._addr = 0;

            queue_signal(env, info.si_signo, &info);

            break;

        case EXCP0D_GPF:

            /* XXX: potential problem if ABI32 */

#ifndef TARGET_X86_64

            if (env->eflags & VM_MASK) {

                handle_vm86_fault(env);

            } else

#endif

            {

                info.si_signo = SIGSEGV;

                info.si_errno = 0;

                info.si_code = TARGET_SI_KERNEL;

                info._sifields._sigfault._addr = 0;

                queue_signal(env, info.si_signo, &info);

            }

            break;

        case EXCP0E_PAGE:

            info.si_signo = SIGSEGV;

            info.si_errno = 0;

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

                info.si_code = TARGET_SEGV_MAPERR;

            else

                info.si_code = TARGET_SEGV_ACCERR;

            info._sifields._sigfault._addr = env->cr[2];

            queue_signal(env, info.si_signo, &info);

            break;

        case EXCP00_DIVZ:

#ifndef TARGET_X86_64

            if (env->eflags & VM_MASK) {

                handle_vm86_trap(env, trapnr);

            } else

#endif

            {

                /* division by zero */

                info.si_signo = SIGFPE;

                info.si_errno = 0;

                info.si_code = TARGET_FPE_INTDIV;

                info._sifields._sigfault._addr = env->eip;

                queue_signal(env, info.si_signo, &info);

            }

            break;

        case EXCP01_DB:

        case EXCP03_INT3:

#ifndef TARGET_X86_64

            if (env->eflags & VM_MASK) {

                handle_vm86_trap(env, trapnr);

            } else

#endif

            {

                info.si_signo = SIGTRAP;

                info.si_errno = 0;

                if (trapnr == EXCP01_DB) {

                    info.si_code = TARGET_TRAP_BRKPT;

                    info._sifields._sigfault._addr = env->eip;

                } else {

                    info.si_code = TARGET_SI_KERNEL;

                    info._sifields._sigfault._addr = 0;

                }

                queue_signal(env, info.si_signo, &info);

            }

            break;

        case EXCP04_INTO:

        case EXCP05_BOUND:

#ifndef TARGET_X86_64

            if (env->eflags & VM_MASK) {

                handle_vm86_trap(env, trapnr);

            } else

#endif

            {

                info.si_signo = SIGSEGV;

                info.si_errno = 0;

                info.si_code = TARGET_SI_KERNEL;

                info._sifields._sigfault._addr = 0;

                queue_signal(env, info.si_signo, &info);

            }

            break;

        case EXCP06_ILLOP:

            info.si_signo = SIGILL;

            info.si_errno = 0;

            info.si_code = TARGET_ILL_ILLOPN;

            info._sifields._sigfault._addr = env->eip;

            queue_signal(env, info.si_signo, &info);

            break;

#endif

        case EXCP_INTERRUPT:

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

            break;

#if 0

        case EXCP_DEBUG:

            {

                int sig;

                sig = gdb_handlesig (env, TARGET_SIGTRAP);

                if (sig)

                  {

                    info.si_signo = sig;

                    info.si_errno = 0;

                    info.si_code = TARGET_TRAP_BRKPT;

                    queue_signal(env, info.si_signo, &info);

                  }

            }

            break;

#endif

        default:

            pc = 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

#ifdef TARGET_SPARC

#define SPARC64_STACK_BIAS 2047

//#define DEBUG_WIN

/* WARNING: dealing with register windows _is_ complicated. More info

   can be found at http://www.sics.se/~psm/sparcstack.html */

static inline int get_reg_index(CPUSPARCState *env, int cwp, int index)

{

    index = (index + cwp * 16) % (16 * env->nwindows);

    /* wrap handling : if cwp is on the last window, then we use the

       registers 'after' the end */

    if (index < 8 && env->cwp == env->nwindows - 1)

        index += 16 * env->nwindows;

    return index;

}

/* save the register window 'cwp1' */

static inline void save_window_offset(CPUSPARCState *env, int cwp1)

{

    unsigned int i;

    abi_ulong sp_ptr;

    sp_ptr = env->regbase[get_reg_index(env, cwp1, 6)];

#ifdef TARGET_SPARC64

    if (sp_ptr & 3)

        sp_ptr += SPARC64_STACK_BIAS;

#endif

#if defined(DEBUG_WIN)

    printf("win_overflow: sp_ptr=0x" TARGET_ABI_FMT_lx " save_cwp=%d\n",

           sp_ptr, cwp1);

#endif

    for(i = 0; i < 16; i++) {

        /* FIXME - what to do if put_user() fails? */

        put_user_ual(env->regbase[get_reg_index(env, cwp1, 8 + i)], sp_ptr);

        sp_ptr += sizeof(abi_ulong);

    }

}

static void save_window(CPUSPARCState *env)

{

#ifndef TARGET_SPARC64

    unsigned int new_wim;

    new_wim = ((env->wim >> 1) | (env->wim << (env->nwindows - 1))) &

        ((1LL << env->nwindows) - 1);

    save_window_offset(env, cpu_cwp_dec(env, env->cwp - 2));

    env->wim = new_wim;

#else

    save_window_offset(env, cpu_cwp_dec(env, env->cwp - 2));

    env->cansave++;

    env->canrestore--;

#endif

}

static void restore_window(CPUSPARCState *env)

{

#ifndef TARGET_SPARC64

    unsigned int new_wim;

#endif

    unsigned int i, cwp1;

    abi_ulong sp_ptr;

#ifndef TARGET_SPARC64

    new_wim = ((env->wim << 1) | (env->wim >> (env->nwindows - 1))) &

        ((1LL << env->nwindows) - 1);

#endif

    /* restore the invalid window */

    cwp1 = cpu_cwp_inc(env, env->cwp + 1);

    sp_ptr = env->regbase[get_reg_index(env, cwp1, 6)];

#ifdef TARGET_SPARC64

    if (sp_ptr & 3)

        sp_ptr += SPARC64_STACK_BIAS;

#endif

#if defined(DEBUG_WIN)

    printf("win_underflow: sp_ptr=0x" TARGET_ABI_FMT_lx " load_cwp=%d\n",

           sp_ptr, cwp1);

#endif

    for(i = 0; i < 16; i++) {

        /* FIXME - what to do if get_user() fails? */

        get_user_ual(env->regbase[get_reg_index(env, cwp1, 8 + i)], sp_ptr);

        sp_ptr += sizeof(abi_ulong);

    }

#ifdef TARGET_SPARC64

    env->canrestore++;

    if (env->cleanwin < env->nwindows - 1)

        env->cleanwin++;

    env->cansave--;

#else

    env->wim = new_wim;

#endif

}

static void flush_windows(CPUSPARCState *env)

{

    int offset, cwp1;

    offset = 1;

    for(;;) {

        /* if restore would invoke restore_window(), then we can stop */

        cwp1 = cpu_cwp_inc(env, env->cwp + offset);

#ifndef TARGET_SPARC64

        if (env->wim & (1 << cwp1))

            break;

#else

        if (env->canrestore == 0)

            break;

        env->cansave++;

        env->canrestore--;

#endif

        save_window_offset(env, cwp1);

        offset++;

    }

    cwp1 = cpu_cwp_inc(env, env->cwp + 1);

#ifndef TARGET_SPARC64

    /* set wim so that restore will reload the registers */

    env->wim = 1 << cwp1;

#endif

#if defined(DEBUG_WIN)

    printf("flush_windows: nb=%d\n", offset - 1);

#endif

}

void cpu_loop(CPUSPARCState *env)

{

    int trapnr, ret, syscall_nr;

    //target_siginfo_t info;

    while (1) {

        trapnr = cpu_sparc_exec (env);

        switch (trapnr) {

#ifndef TARGET_SPARC64

        case 0x80:

#else

        /* FreeBSD uses 0x141 for syscalls too */

        case 0x141:

            if (bsd_type != target_freebsd)

                goto badtrap;

        case 0x100:

#endif

            syscall_nr = env->gregs[1];

            if (bsd_type == target_freebsd)

                ret = do_freebsd_syscall(env, syscall_nr,

                                         env->regwptr[0], env->regwptr[1],

                                         env->regwptr[2], env->regwptr[3],

                                         env->regwptr[4], env->regwptr[5], 0, 0);

            else if (bsd_type == target_netbsd)

                ret = do_netbsd_syscall(env, syscall_nr,

                                        env->regwptr[0], env->regwptr[1],

                                        env->regwptr[2], env->regwptr[3],

                                        env->regwptr[4], env->regwptr[5]);

            else { //if (bsd_type == target_openbsd)

#if defined(TARGET_SPARC64)

                syscall_nr &= ~(TARGET_OPENBSD_SYSCALL_G7RFLAG |

                                TARGET_OPENBSD_SYSCALL_G2RFLAG);

#endif

                ret = do_openbsd_syscall(env, syscall_nr,

                                         env->regwptr[0], env->regwptr[1],

                                         env->regwptr[2], env->regwptr[3],

                                         env->regwptr[4], env->regwptr[5]);

            }

            if ((unsigned int)ret >= (unsigned int)(-515)) {

                ret = -ret;

#if defined(TARGET_SPARC64) && !defined(TARGET_ABI32)

                env->xcc |= PSR_CARRY;

#else

                env->psr |= PSR_CARRY;

#endif

            } else {

#if defined(TARGET_SPARC64) && !defined(TARGET_ABI32)

                env->xcc &= ~PSR_CARRY;

#else

                env->psr &= ~PSR_CARRY;

#endif

            }

            env->regwptr[0] = ret;

            /* next instruction */

#if defined(TARGET_SPARC64)

            if (bsd_type == target_openbsd &&

                env->gregs[1] & TARGET_OPENBSD_SYSCALL_G2RFLAG) {

                env->pc = env->gregs[2];

                env->npc = env->pc + 4;

            } else if (bsd_type == target_openbsd &&

                       env->gregs[1] & TARGET_OPENBSD_SYSCALL_G7RFLAG) {

                env->pc = env->gregs[7];

                env->npc = env->pc + 4;

            } else {

                env->pc = env->npc;

                env->npc = env->npc + 4;

            }

#else

            env->pc = env->npc;

            env->npc = env->npc + 4;

#endif

            break;

        case 0x83: /* flush windows */

#ifdef TARGET_ABI32

        case 0x103:

#endif

            flush_windows(env);

            /* next instruction */

            env->pc = env->npc;

            env->npc = env->npc + 4;

            break;

#ifndef TARGET_SPARC64

        case TT_WIN_OVF: /* window overflow */

            save_window(env);

            break;

        case TT_WIN_UNF: /* window underflow */

            restore_window(env);

            break;

        case TT_TFAULT:

        case TT_DFAULT:

#if 0

            {

                info.si_signo = SIGSEGV;

                info.si_errno = 0;

                /* XXX: check env->error_code */

                info.si_code = TARGET_SEGV_MAPERR;

                info._sifields._sigfault._addr = env->mmuregs[4];

                queue_signal(env, info.si_signo, &info);

            }

#endif

            break;

#else

        case TT_SPILL: /* window overflow */

            save_window(env);

            break;

        case TT_FILL: /* window underflow */

            restore_window(env);

            break;

        case TT_TFAULT:

        case TT_DFAULT:

#if 0

            {

                info.si_signo = SIGSEGV;

                info.si_errno = 0;

                /* XXX: check env->error_code */

                info.si_code = TARGET_SEGV_MAPERR;

                if (trapnr == TT_DFAULT)

                    info._sifields._sigfault._addr = env->dmmuregs[4];

                else

                    info._sifields._sigfault._addr = env->tsptr->tpc;

                //queue_signal(env, info.si_signo, &info);

            }

#endif

            break;

#endif

        case EXCP_INTERRUPT:

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

            break;

        case EXCP_DEBUG:

            {

                int sig;

                sig = gdb_handlesig (env, TARGET_SIGTRAP);

#if 0

                if (sig)

                  {

                    info.si_signo = sig;

                    info.si_errno = 0;

                    info.si_code = TARGET_TRAP_BRKPT;

                    //queue_signal(env, info.si_signo, &info);

                  }

#endif

            }

            break;

        default:

#ifdef TARGET_SPARC64

        badtrap:

#endif

            printf ("Unhandled trap: 0x%x\n", trapnr);

            cpu_dump_state(env, stderr, fprintf, 0);

            exit (1);

        }

        process_pending_signals (env);

    }

}

#endif

static void usage(void)

{

    printf("qemu-" TARGET_ARCH " version " QEMU_VERSION ", Copyright (c) 2003-2008 Fabrice Bellard\n"

           "usage: qemu-" TARGET_ARCH " [options] program [arguments...]\n"

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

           "\n"

           "Standard options:\n"

           "-h                print this help\n"

           "-g port           wait gdb connection to port\n"

           "-L path           set the elf interpreter prefix (default=%s)\n"

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

           "-cpu model        select CPU (-cpu ? for list)\n"

           "-drop-ld-preload  drop LD_PRELOAD for target process\n"

           "-E var=value      sets/modifies targets environment variable(s)\n"

           "-U var            unsets targets environment variable(s)\n"

#if defined(CONFIG_USE_GUEST_BASE)

           "-B address        set guest_base address to address\n"

#endif

           "-bsd type         select emulated BSD type FreeBSD/NetBSD/OpenBSD (default)\n"

           "\n"

           "Debug options:\n"

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

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

           "-singlestep  always run in singlestep mode\n"

           "-strace      log system calls\n"

           "\n"

           "Environment variables:\n"

           "QEMU_STRACE       Print system calls and arguments similar to the\n"

           "                  'strace' program.  Enable by setting to any value.\n"

           "You can use -E and -U options to set/unset environment variables\n"

           "for target process.  It is possible to provide several variables\n"

           "by repeating the option.  For example:\n"

           "    -E var1=val2 -E var2=val2 -U LD_PRELOAD -U LD_DEBUG\n"

           "Note that if you provide several changes to single variable\n"

           "last change will stay in effect.\n"

           ,

           TARGET_ARCH,

           interp_prefix,

           x86_stack_size,

           DEBUG_LOGFILE);

    exit(1);

}

THREAD CPUState *thread_env;

/* Assumes contents are already zeroed.  */

void init_task_state(TaskState *ts)

{

    int i;

    ts->used = 1;

    ts->first_free = ts->sigqueue_table;

    for (i = 0; i < MAX_SIGQUEUE_SIZE - 1; i++) {

        ts->sigqueue_table[i].next = &ts->sigqueue_table[i + 1];

    }

    ts->sigqueue_table[i].next = NULL;

}

int main(int argc, char **argv)

{

    const char *filename;

    const char *cpu_model;

    struct target_pt_regs regs1, *regs = &regs1;

    struct image_info info1, *info = &info1;

    TaskState ts1, *ts = &ts1;

    CPUState *env;

    int optind;

    const char *r;

    int gdbstub_port = 0;

    char **target_environ, **wrk;

    envlist_t *envlist = NULL;

    bsd_type = target_openbsd;

    if (argc <= 1)

        usage();

    /* init debug */

    cpu_set_log_filename(DEBUG_LOGFILE);

    if ((envlist = envlist_create()) == NULL) {

        (void) fprintf(stderr, "Unable to allocate envlist\n");

        exit(1);

    }

    /* add current environment into the list */

    for (wrk = environ; *wrk != NULL; wrk++) {

        (void) envlist_setenv(envlist, *wrk);

    }

    cpu_model = NULL;

#if defined(cpudef_setup)

    cpudef_setup(); /* parse cpu definitions in target config file (TBD) */

#endif

    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;

            const 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, "E")) {

            r = argv[optind++];

            if (envlist_setenv(envlist, r) != 0)

                usage();

        } else if (!strcmp(r, "ignore-environment")) {

            envlist_free(envlist);

            if ((envlist = envlist_create()) == NULL) {

                (void) fprintf(stderr, "Unable to allocate envlist\n");

                exit(1);

            }

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

            r = argv[optind++];

            if (envlist_unsetenv(envlist, r) != 0)

                usage();

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

            r = argv[optind++];

            x86_stack_size = strtol(r, (char **)&r, 0);

            if (x86_stack_size <= 0)

                usage();

            if (*r == 'M')

                x86_stack_size *= 1024 * 1024;

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

                x86_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")) {

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

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

            qemu_uname_release = argv[optind++];

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

            cpu_model = argv[optind++];

            if (strcmp(cpu_model, "?") == 0) {

/* XXX: implement xxx_cpu_list for targets that still miss it */

#if defined(cpu_list)

                    cpu_list(stdout, &fprintf);

#endif

                exit(1);

            }

#if defined(CONFIG_USE_GUEST_BASE)

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

           guest_base = strtol(argv[optind++], NULL, 0);

           have_guest_base = 1;

#endif

        } else if (!strcmp(r, "drop-ld-preload")) {

            (void) envlist_unsetenv(envlist, "LD_PRELOAD");

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

            if (!strcasecmp(argv[optind], "freebsd")) {

                bsd_type = target_freebsd;

            } else if (!strcasecmp(argv[optind], "netbsd")) {

                bsd_type = target_netbsd;

            } else if (!strcasecmp(argv[optind], "openbsd")) {

                bsd_type = target_openbsd;

            } else {

                usage();

            }

            optind++;

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

            singlestep = 1;

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

            do_strace = 1;

        } else

        {