main.c

qemu虚拟机代码

    unsigned int syscall_num;
    target_ulong arg5, arg6, sp_reg;

    for(;;) {
        trapnr = cpu_mips_exec(env);
        switch(trapnr) {
        case EXCP_SYSCALL:
            {
                syscall_num = env->gpr[2] - 4000;
                if (syscall_num >= sizeof(mips_syscall_args)) {
                    ret = -ENOSYS;
                } else {
                    nb_args = mips_syscall_args[syscall_num];
                    if (nb_args >= 5) {
                        sp_reg = env->gpr[29];
                        /* these arguments are taken from the stack */
                        arg5 = tgetl(sp_reg + 16);
                        if (nb_args >= 6) {
                            arg6 = tgetl(sp_reg + 20);
                        } else {
                            arg6 = 0;
                        }
                    } else {
                        arg5 = 0;
                        arg6 = 0;
                    }
                    ret = do_syscall(env, 
                                     env->gpr[2], 
                                     env->gpr[4],
                                     env->gpr[5],
                                     env->gpr[6],
                                     env->gpr[7],
                                     arg5, 
                                     arg6);
                }
                fail:
                env->PC += 4;
                if ((unsigned int)ret >= (unsigned int)(-1133)) {
                    env->gpr[7] = 1; /* error flag */
                    ret = -ret;
                    env->gpr[0] = ret;
                    env->gpr[2] = ret;
                } else {
                    env->gpr[7] = 0; /* error flag */
                    env->gpr[2] = ret;
                }
            }
            break;
        case EXCP_CpU:
        case EXCP_RI:
            {
                uint32_t insn, op;

                insn = tget32(env->PC);
                op = insn >> 26;
                //                printf("insn=%08x op=%02x\n", insn, op);
                /* XXX: totally dummy FP ops just to be able to launch
                   a few executables */
                switch(op) {
                case 0x31: /* LWC1 */
                    env->PC += 4;
                    break;
                case 0x39: /* SWC1 */
                    env->PC += 4;
                    break;
                case 0x11:
                    switch((insn >> 21) & 0x1f) {
                    case 0x02: /* CFC1 */
                        env->PC += 4;
                        break;
                    default:
                        goto sigill;
                    }
                    break;
                default:
                sigill:
                    info.si_signo = TARGET_SIGILL;
                    info.si_errno = 0;
                    info.si_code = 0;
                    queue_signal(info.si_signo, &info);
                    break;
                }
            }
            break;
        default:
            //        error:
            fprintf(stderr, "qemu: unhandled CPU exception 0x%x - aborting\n", 
                    trapnr);
            cpu_dump_state(env, stderr, fprintf, 0);
            abort();
        }
        process_pending_signals(env);
    }
}
#endif

#ifdef TARGET_SH4
void cpu_loop (CPUState *env)
{
    int trapnr, ret;
    //    target_siginfo_t info;
    
    while (1) {
        trapnr = cpu_sh4_exec (env);
        
        switch (trapnr) {
        case 0x160:
            ret = do_syscall(env, 
                             env->gregs[0x13], 
                             env->gregs[0x14], 
                             env->gregs[0x15], 
                             env->gregs[0x16], 
                             env->gregs[0x17], 
                             env->gregs[0x10], 
                             0);
            env->gregs[0x10] = ret;
            env->pc += 2;
            break;
        default:
            printf ("Unhandled trap: 0x%x\n", trapnr);
            cpu_dump_state(env, stderr, fprintf, 0);
            exit (1);
        }
        process_pending_signals (env);
    }
}
#endif

void usage(void)
{
    printf("qemu-" TARGET_ARCH " version " QEMU_VERSION ", Copyright (c) 2003-2005 Fabrice Bellard\n"
           "usage: qemu-" TARGET_ARCH " [-h] [-g] [-d opts] [-L path] [-s size] program [arguments...]\n"
           "Linux CPU emulator (compiled for %s emulation)\n"
           "\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"
           "\n"
           "debug options:\n"
#ifdef USE_CODE_COPY
           "-no-code-copy   disable code copy acceleration\n"
#endif
           "-d options   activate log (logfile=%s)\n"
           "-p pagesize  set the host page size to 'pagesize'\n",
           TARGET_ARCH,
           interp_prefix, 
           x86_stack_size,
           DEBUG_LOGFILE);
    _exit(1);
}

/* XXX: currently only used for async signals (see signal.c) */
CPUState *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;
    CPUState *env;
    int optind;
    const char *r;
    int gdbstub_port = 0;
    
    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++];
            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 
#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));

    /* 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
       qemu_host_page_size */
    env = cpu_init();
    global_env = env;
    
    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, "entry       0x%08lx\n" , info->entry);
    }

    target_set_brk(info->brk);
    syscall_init();
    signal_init();

    /* 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;
    
    /* 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 = h2g(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 = h2g(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);

#elif defined(TARGET_ARM)
    {
        int i;
        cpu_arm_set_model(env, ARM_CPUID_ARM1026);
        cpsr_write(env, regs->uregs[16], 0xffffffff);
        for(i = 0; i < 16; i++) {
            env->regs[i] = regs->uregs[i];
        }
        ts->stack_base = info->start_stack;
        ts->heap_base = info->brk;
        /* This will be filled in on the first SYS_HEAPINFO call.  */
        ts->heap_limit = 0;
    }
#elif defined(TARGET_SPARC)
    {
        int i;
	env->pc = regs->pc;
	env->npc = regs->npc;
        env->y = regs->y;
        for(i = 0; i < 8; i++)
            env->gregs[i] = regs->u_regs[i];
        for(i = 0; i < 8; i++)
            env->regwptr[i] = regs->u_regs[i + 8];
    }
#elif defined(TARGET_PPC)
    {
        ppc_def_t *def;
        int i;

        /* Choose and initialise CPU */
        /* XXX: CPU model (or PVR) should be provided on command line */
        //        ppc_find_by_name("750gx", &def);
        //        ppc_find_by_name("750fx", &def);
        //        ppc_find_by_name("750p", &def);
        ppc_find_by_name("750", &def);
        //        ppc_find_by_name("G3", &def);
        //        ppc_find_by_name("604r", &def);
        //        ppc_find_by_name("604e", &def);
        //        ppc_find_by_name("604", &def);
        if (def == NULL) {
            cpu_abort(env,
                      "Unable to find PowerPC CPU definition\n");
        }
        cpu_ppc_register(env, def);

        for (i = 0; i < 32; i++) {
            if (i != 12 && i != 6 && i != 13)
                env->msr[i] = (regs->msr >> i) & 1;
        }
        env->nip = regs->nip;
        for(i = 0; i < 32; i++) {
            env->gpr[i] = regs->gpr[i];
        }
    }
#elif defined(TARGET_MIPS)
    {
        int i;

        for(i = 0; i < 32; i++) {
            env->gpr[i] = regs->regs[i];
        }
        env->PC = regs->cp0_epc;
    }
#elif defined(TARGET_SH4)
    {
        int i;

        for(i = 0; i < 16; i++) {
            env->gregs[i] = regs->regs[i];
        }
        env->pc = regs->pc;
    }
#else
#error unsupported target CPU
#endif

    if (gdbstub_port) {
        gdbserver_start (gdbstub_port);
        gdb_handlesig(env, 0);
    }
    cpu_loop(env);
    /* never exits */
    return 0;
}