Archipelago » qemu

/*

 *  qemu main

 * 

 *  Copyright (c) 2003 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, 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 "qemu.h"

#include "cpu-i386.h"

#define DEBUG_LOGFILE "/tmp/qemu.log"

FILE *logfile = NULL;

int loglevel;

static const char *interp_prefix = CONFIG_QEMU_PREFIX;

#ifdef __i386__

/* Force usage of an ELF interpreter even if it is an ELF shared

   object ! */

const char interp[] __attribute__((section(".interp"))) = "/lib/ld-linux.so.2";

/* for recent libc, we add these dummies symbol which are not declared

   when generating a linked object (bug in ld ?) */

#if __GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 3)

long __init_array_start[0];

long __init_array_end[0];

long __fini_array_start[0];

long __fini_array_end[0];

#endif

#endif

/* 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);

}

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

/* CPUX86 core interface */

void cpu_x86_outb(CPUX86State *env, int addr, int val)

{

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

}

void cpu_x86_outw(CPUX86State *env, int addr, int val)

{

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

}

void cpu_x86_outl(CPUX86State *env, int addr, int val)

{

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

}

int cpu_x86_inb(CPUX86State *env, int addr)

{

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

    return 0;

}

int cpu_x86_inw(CPUX86State *env, int addr)

{

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

    return 0;

}

int cpu_x86_inl(CPUX86State *env, int addr)

{

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

    return 0;

}

static 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);

}

uint64_t gdt_table[6];

uint64_t idt_table[256];

/* 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);

}

void cpu_loop(CPUX86State *env)

{

    int trapnr;

    uint8_t *pc;

    target_siginfo_t info;

    for(;;) {

        trapnr = cpu_x86_exec(env);

        switch(trapnr) {

        case 0x80:

            /* linux syscall */

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

            break;

        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(info.si_signo, &info);

            break;

        case EXCP0D_GPF:

            if (env->eflags & VM_MASK) {

                handle_vm86_fault(env);

            } else {

                info.si_signo = SIGSEGV;

                info.si_errno = 0;

                info.si_code = TARGET_SI_KERNEL;

                info._sifields._sigfault._addr = 0;

                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 = TARGET_SEGV_MAPERR;

            else

                info.si_code = TARGET_SEGV_ACCERR;

            info._sifields._sigfault._addr = env->cr2;

            queue_signal(info.si_signo, &info);

            break;

        case EXCP00_DIVZ:

            if (env->eflags & VM_MASK) {

                handle_vm86_trap(env, trapnr);

            } else {

                /* 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(info.si_signo, &info);

            }

            break;

        case EXCP01_SSTP:

        case EXCP03_INT3:

            if (env->eflags & VM_MASK) {

                handle_vm86_trap(env, trapnr);

            } else {

                info.si_signo = SIGTRAP;

                info.si_errno = 0;

                if (trapnr == EXCP01_SSTP) {

                    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(info.si_signo, &info);

            }

            break;

        case EXCP04_INTO:

        case EXCP05_BOUND:

            if (env->eflags & VM_MASK) {

                handle_vm86_trap(env, trapnr);

            } else {

                info.si_signo = SIGSEGV;

                info.si_errno = 0;

                info.si_code = TARGET_SI_KERNEL;

                info._sifields._sigfault._addr = 0;

                queue_signal(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(info.si_signo, &info);

            break;

        case EXCP_INTERRUPT:

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

            break;

        default:

            pc = env->seg_cache[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);

    }

}

void usage(void)

{

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

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

           "Linux x86 emulator\n"

           "\n"

           "-h           print this help\n"

           "-L path      set the x86 elf interpreter prefix (default=%s)\n"

           "-s size      set the x86 stack size in bytes (default=%ld)\n"

           "\n"

           "debug options:\n"

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

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

           interp_prefix, 

           x86_stack_size,

           DEBUG_LOGFILE);

    _exit(1);

}

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

CPUX86State *global_env;

/* 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;

    struct image_info info1, *info = &info1;

    TaskState ts1, *ts = &ts1;

    CPUX86State *env;

    int optind;

    const char *r;

    if (argc <= 1)

        usage();

    loglevel = 0;

    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")) {

            loglevel = 1;

        } 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")) {

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

            if (host_page_size == 0 ||

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

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

                exit(1);

            }

        } else {

            usage();

        }

    }

    if (optind >= argc)

        usage();

    filename = argv[optind];

    /* init debug */

    if (loglevel) {

        logfile = fopen(DEBUG_LOGFILE, "w");

        if (!logfile) {

            perror(DEBUG_LOGFILE);

            _exit(1);

        }

        setvbuf(logfile, NULL, _IOLBF, 0);

    }

    /* Zero out regs */

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

    /* Zero out image_info */

    memset(info, 0, sizeof(struct image_info));

    /* Scan interp_prefix dir for replacement files. */

    init_paths(interp_prefix);

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

       host_page_size */

    env = cpu_x86_init();

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

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

        _exit(1);

    }

    if (loglevel) {

        page_dump(logfile);

        fprintf(logfile, "start_brk   0x%08lx\n" , info->start_brk);

        fprintf(logfile, "end_code    0x%08lx\n" , info->end_code);

        fprintf(logfile, "start_code  0x%08lx\n" , info->start_code);

        fprintf(logfile, "end_data    0x%08lx\n" , info->end_data);

        fprintf(logfile, "start_stack 0x%08lx\n" , info->start_stack);

        fprintf(logfile, "brk         0x%08lx\n" , info->brk);

        fprintf(logfile, "esp         0x%08lx\n" , regs->esp);

        fprintf(logfile, "eip         0x%08lx\n" , regs->eip);

    }

    target_set_brk((char *)info->brk);

    syscall_init();

    signal_init();

    global_env = env;

    /* build Task State */

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

    env->opaque = ts;

    ts->used = 1;

    /* linux 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;

    /* linux interrupt setup */

    env->idt.base = (void *)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);

    set_idt(5, 3);

    set_idt(6, 0);

    set_idt(7, 0);

    set_idt(8, 0);

    set_idt(9, 0);

    set_idt(10, 0);

    set_idt(11, 0);

    set_idt(12, 0);

    set_idt(13, 0);

    set_idt(14, 0);

    set_idt(15, 0);

    set_idt(16, 0);

    set_idt(17, 0);

    set_idt(18, 0);

    set_idt(19, 0);

    set_idt(0x80, 3);

    /* linux segment setup */

    env->gdt.base = (void *)gdt_table;

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

    write_dt(&gdt_table[__USER_CS >> 3], 0, 0xfffff,

             DESC_G_MASK | DESC_B_MASK | DESC_P_MASK | DESC_S_MASK | 

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

    write_dt(&gdt_table[__USER_DS >> 3], 0, 0xfffff,

             DESC_G_MASK | DESC_B_MASK | DESC_P_MASK | DESC_S_MASK | 

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

    cpu_x86_load_seg(env, R_CS, __USER_CS);

    cpu_x86_load_seg(env, R_DS, __USER_DS);

    cpu_x86_load_seg(env, R_ES, __USER_DS);

    cpu_x86_load_seg(env, R_SS, __USER_DS);

    cpu_x86_load_seg(env, R_FS, __USER_DS);

    cpu_x86_load_seg(env, R_GS, __USER_DS);

    cpu_loop(env);

    /* never exits */

    return 0;

}