xref: /openbmc/qemu/linux-user/main.c (revision 76d0042bb2a7601e7a343fd2ff02902658f8a97a)
1 /*
2  *  qemu user main
3  *
4  *  Copyright (c) 2003-2008 Fabrice Bellard
5  *
6  *  This program is free software; you can redistribute it and/or modify
7  *  it under the terms of the GNU General Public License as published by
8  *  the Free Software Foundation; either version 2 of the License, or
9  *  (at your option) any later version.
10  *
11  *  This program is distributed in the hope that it will be useful,
12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  *  GNU General Public License for more details.
15  *
16  *  You should have received a copy of the GNU General Public License
17  *  along with this program; if not, see <http://www.gnu.org/licenses/>.
18  */
19 
20 #include "qemu/osdep.h"
21 #include "qemu-common.h"
22 #include "qemu/units.h"
23 #include "qemu/accel.h"
24 #include "sysemu/tcg.h"
25 #include "qemu-version.h"
26 #include <sys/syscall.h>
27 #include <sys/resource.h>
28 #include <sys/shm.h>
29 #include <linux/binfmts.h>
30 
31 #include "qapi/error.h"
32 #include "qemu.h"
33 #include "qemu/path.h"
34 #include "qemu/queue.h"
35 #include "qemu/config-file.h"
36 #include "qemu/cutils.h"
37 #include "qemu/error-report.h"
38 #include "qemu/help_option.h"
39 #include "qemu/module.h"
40 #include "qemu/plugin.h"
41 #include "exec/exec-all.h"
42 #include "tcg/tcg.h"
43 #include "qemu/timer.h"
44 #include "qemu/envlist.h"
45 #include "qemu/guest-random.h"
46 #include "elf.h"
47 #include "trace/control.h"
48 #include "target_elf.h"
49 #include "cpu_loop-common.h"
50 #include "crypto/init.h"
51 #include "fd-trans.h"
52 
53 #ifndef AT_FLAGS_PRESERVE_ARGV0
54 #define AT_FLAGS_PRESERVE_ARGV0_BIT 0
55 #define AT_FLAGS_PRESERVE_ARGV0 (1 << AT_FLAGS_PRESERVE_ARGV0_BIT)
56 #endif
57 
58 char *exec_path;
59 
60 int singlestep;
61 static const char *argv0;
62 static const char *gdbstub;
63 static envlist_t *envlist;
64 static const char *cpu_model;
65 static const char *cpu_type;
66 static const char *seed_optarg;
67 unsigned long mmap_min_addr;
68 uintptr_t guest_base;
69 bool have_guest_base;
70 
71 /*
72  * Used to implement backwards-compatibility for the `-strace`, and
73  * QEMU_STRACE options. Without this, the QEMU_LOG can be overwritten by
74  * -strace, or vice versa.
75  */
76 static bool enable_strace;
77 
78 /*
79  * The last log mask given by the user in an environment variable or argument.
80  * Used to support command line arguments overriding environment variables.
81  */
82 static int last_log_mask;
83 
84 /*
85  * When running 32-on-64 we should make sure we can fit all of the possible
86  * guest address space into a contiguous chunk of virtual host memory.
87  *
88  * This way we will never overlap with our own libraries or binaries or stack
89  * or anything else that QEMU maps.
90  *
91  * Many cpus reserve the high bit (or more than one for some 64-bit cpus)
92  * of the address for the kernel.  Some cpus rely on this and user space
93  * uses the high bit(s) for pointer tagging and the like.  For them, we
94  * must preserve the expected address space.
95  */
96 #ifndef MAX_RESERVED_VA
97 # if HOST_LONG_BITS > TARGET_VIRT_ADDR_SPACE_BITS
98 #  if TARGET_VIRT_ADDR_SPACE_BITS == 32 && \
99       (TARGET_LONG_BITS == 32 || defined(TARGET_ABI32))
100 /* There are a number of places where we assign reserved_va to a variable
101    of type abi_ulong and expect it to fit.  Avoid the last page.  */
102 #   define MAX_RESERVED_VA(CPU)  (0xfffffffful & TARGET_PAGE_MASK)
103 #  else
104 #   define MAX_RESERVED_VA(CPU)  (1ul << TARGET_VIRT_ADDR_SPACE_BITS)
105 #  endif
106 # else
107 #  define MAX_RESERVED_VA(CPU)  0
108 # endif
109 #endif
110 
111 unsigned long reserved_va;
112 
113 static void usage(int exitcode);
114 
115 static const char *interp_prefix = CONFIG_QEMU_INTERP_PREFIX;
116 const char *qemu_uname_release;
117 
118 /* XXX: on x86 MAP_GROWSDOWN only works if ESP <= address + 32, so
119    we allocate a bigger stack. Need a better solution, for example
120    by remapping the process stack directly at the right place */
121 unsigned long guest_stack_size = 8 * 1024 * 1024UL;
122 
123 /***********************************************************/
124 /* Helper routines for implementing atomic operations.  */
125 
126 /* Make sure everything is in a consistent state for calling fork().  */
127 void fork_start(void)
128 {
129     start_exclusive();
130     mmap_fork_start();
131     cpu_list_lock();
132 }
133 
134 void fork_end(int child)
135 {
136     mmap_fork_end(child);
137     if (child) {
138         CPUState *cpu, *next_cpu;
139         /* Child processes created by fork() only have a single thread.
140            Discard information about the parent threads.  */
141         CPU_FOREACH_SAFE(cpu, next_cpu) {
142             if (cpu != thread_cpu) {
143                 QTAILQ_REMOVE_RCU(&cpus, cpu, node);
144             }
145         }
146         qemu_init_cpu_list();
147         gdbserver_fork(thread_cpu);
148         /* qemu_init_cpu_list() takes care of reinitializing the
149          * exclusive state, so we don't need to end_exclusive() here.
150          */
151     } else {
152         cpu_list_unlock();
153         end_exclusive();
154     }
155 }
156 
157 __thread CPUState *thread_cpu;
158 
159 bool qemu_cpu_is_self(CPUState *cpu)
160 {
161     return thread_cpu == cpu;
162 }
163 
164 void qemu_cpu_kick(CPUState *cpu)
165 {
166     cpu_exit(cpu);
167 }
168 
169 void task_settid(TaskState *ts)
170 {
171     if (ts->ts_tid == 0) {
172         ts->ts_tid = (pid_t)syscall(SYS_gettid);
173     }
174 }
175 
176 void stop_all_tasks(void)
177 {
178     /*
179      * We trust that when using NPTL, start_exclusive()
180      * handles thread stopping correctly.
181      */
182     start_exclusive();
183 }
184 
185 /* Assumes contents are already zeroed.  */
186 void init_task_state(TaskState *ts)
187 {
188     ts->used = 1;
189     ts->sigaltstack_used = (struct target_sigaltstack) {
190         .ss_sp = 0,
191         .ss_size = 0,
192         .ss_flags = TARGET_SS_DISABLE,
193     };
194 }
195 
196 CPUArchState *cpu_copy(CPUArchState *env)
197 {
198     CPUState *cpu = env_cpu(env);
199     CPUState *new_cpu = cpu_create(cpu_type);
200     CPUArchState *new_env = new_cpu->env_ptr;
201     CPUBreakpoint *bp;
202 
203     /* Reset non arch specific state */
204     cpu_reset(new_cpu);
205 
206     new_cpu->tcg_cflags = cpu->tcg_cflags;
207     memcpy(new_env, env, sizeof(CPUArchState));
208 
209     /* Clone all break/watchpoints.
210        Note: Once we support ptrace with hw-debug register access, make sure
211        BP_CPU break/watchpoints are handled correctly on clone. */
212     QTAILQ_INIT(&new_cpu->breakpoints);
213     QTAILQ_FOREACH(bp, &cpu->breakpoints, entry) {
214         cpu_breakpoint_insert(new_cpu, bp->pc, bp->flags, NULL);
215     }
216 
217     return new_env;
218 }
219 
220 static void handle_arg_help(const char *arg)
221 {
222     usage(EXIT_SUCCESS);
223 }
224 
225 static void handle_arg_log(const char *arg)
226 {
227     last_log_mask = qemu_str_to_log_mask(arg);
228     if (!last_log_mask) {
229         qemu_print_log_usage(stdout);
230         exit(EXIT_FAILURE);
231     }
232 }
233 
234 static void handle_arg_dfilter(const char *arg)
235 {
236     qemu_set_dfilter_ranges(arg, &error_fatal);
237 }
238 
239 static void handle_arg_log_filename(const char *arg)
240 {
241     qemu_set_log_filename(arg, &error_fatal);
242 }
243 
244 static void handle_arg_set_env(const char *arg)
245 {
246     char *r, *p, *token;
247     r = p = strdup(arg);
248     while ((token = strsep(&p, ",")) != NULL) {
249         if (envlist_setenv(envlist, token) != 0) {
250             usage(EXIT_FAILURE);
251         }
252     }
253     free(r);
254 }
255 
256 static void handle_arg_unset_env(const char *arg)
257 {
258     char *r, *p, *token;
259     r = p = strdup(arg);
260     while ((token = strsep(&p, ",")) != NULL) {
261         if (envlist_unsetenv(envlist, token) != 0) {
262             usage(EXIT_FAILURE);
263         }
264     }
265     free(r);
266 }
267 
268 static void handle_arg_argv0(const char *arg)
269 {
270     argv0 = strdup(arg);
271 }
272 
273 static void handle_arg_stack_size(const char *arg)
274 {
275     char *p;
276     guest_stack_size = strtoul(arg, &p, 0);
277     if (guest_stack_size == 0) {
278         usage(EXIT_FAILURE);
279     }
280 
281     if (*p == 'M') {
282         guest_stack_size *= MiB;
283     } else if (*p == 'k' || *p == 'K') {
284         guest_stack_size *= KiB;
285     }
286 }
287 
288 static void handle_arg_ld_prefix(const char *arg)
289 {
290     interp_prefix = strdup(arg);
291 }
292 
293 static void handle_arg_pagesize(const char *arg)
294 {
295     qemu_host_page_size = atoi(arg);
296     if (qemu_host_page_size == 0 ||
297         (qemu_host_page_size & (qemu_host_page_size - 1)) != 0) {
298         fprintf(stderr, "page size must be a power of two\n");
299         exit(EXIT_FAILURE);
300     }
301 }
302 
303 static void handle_arg_seed(const char *arg)
304 {
305     seed_optarg = arg;
306 }
307 
308 static void handle_arg_gdb(const char *arg)
309 {
310     gdbstub = g_strdup(arg);
311 }
312 
313 static void handle_arg_uname(const char *arg)
314 {
315     qemu_uname_release = strdup(arg);
316 }
317 
318 static void handle_arg_cpu(const char *arg)
319 {
320     cpu_model = strdup(arg);
321     if (cpu_model == NULL || is_help_option(cpu_model)) {
322         /* XXX: implement xxx_cpu_list for targets that still miss it */
323 #if defined(cpu_list)
324         cpu_list();
325 #endif
326         exit(EXIT_FAILURE);
327     }
328 }
329 
330 static void handle_arg_guest_base(const char *arg)
331 {
332     guest_base = strtol(arg, NULL, 0);
333     have_guest_base = true;
334 }
335 
336 static void handle_arg_reserved_va(const char *arg)
337 {
338     char *p;
339     int shift = 0;
340     reserved_va = strtoul(arg, &p, 0);
341     switch (*p) {
342     case 'k':
343     case 'K':
344         shift = 10;
345         break;
346     case 'M':
347         shift = 20;
348         break;
349     case 'G':
350         shift = 30;
351         break;
352     }
353     if (shift) {
354         unsigned long unshifted = reserved_va;
355         p++;
356         reserved_va <<= shift;
357         if (reserved_va >> shift != unshifted) {
358             fprintf(stderr, "Reserved virtual address too big\n");
359             exit(EXIT_FAILURE);
360         }
361     }
362     if (*p) {
363         fprintf(stderr, "Unrecognised -R size suffix '%s'\n", p);
364         exit(EXIT_FAILURE);
365     }
366 }
367 
368 static void handle_arg_singlestep(const char *arg)
369 {
370     singlestep = 1;
371 }
372 
373 static void handle_arg_strace(const char *arg)
374 {
375     enable_strace = true;
376 }
377 
378 static void handle_arg_version(const char *arg)
379 {
380     printf("qemu-" TARGET_NAME " version " QEMU_FULL_VERSION
381            "\n" QEMU_COPYRIGHT "\n");
382     exit(EXIT_SUCCESS);
383 }
384 
385 static void handle_arg_trace(const char *arg)
386 {
387     trace_opt_parse(arg);
388 }
389 
390 #if defined(TARGET_XTENSA)
391 static void handle_arg_abi_call0(const char *arg)
392 {
393     xtensa_set_abi_call0();
394 }
395 #endif
396 
397 static QemuPluginList plugins = QTAILQ_HEAD_INITIALIZER(plugins);
398 
399 #ifdef CONFIG_PLUGIN
400 static void handle_arg_plugin(const char *arg)
401 {
402     qemu_plugin_opt_parse(arg, &plugins);
403 }
404 #endif
405 
406 struct qemu_argument {
407     const char *argv;
408     const char *env;
409     bool has_arg;
410     void (*handle_opt)(const char *arg);
411     const char *example;
412     const char *help;
413 };
414 
415 static const struct qemu_argument arg_table[] = {
416     {"h",          "",                 false, handle_arg_help,
417      "",           "print this help"},
418     {"help",       "",                 false, handle_arg_help,
419      "",           ""},
420     {"g",          "QEMU_GDB",         true,  handle_arg_gdb,
421      "port",       "wait gdb connection to 'port'"},
422     {"L",          "QEMU_LD_PREFIX",   true,  handle_arg_ld_prefix,
423      "path",       "set the elf interpreter prefix to 'path'"},
424     {"s",          "QEMU_STACK_SIZE",  true,  handle_arg_stack_size,
425      "size",       "set the stack size to 'size' bytes"},
426     {"cpu",        "QEMU_CPU",         true,  handle_arg_cpu,
427      "model",      "select CPU (-cpu help for list)"},
428     {"E",          "QEMU_SET_ENV",     true,  handle_arg_set_env,
429      "var=value",  "sets targets environment variable (see below)"},
430     {"U",          "QEMU_UNSET_ENV",   true,  handle_arg_unset_env,
431      "var",        "unsets targets environment variable (see below)"},
432     {"0",          "QEMU_ARGV0",       true,  handle_arg_argv0,
433      "argv0",      "forces target process argv[0] to be 'argv0'"},
434     {"r",          "QEMU_UNAME",       true,  handle_arg_uname,
435      "uname",      "set qemu uname release string to 'uname'"},
436     {"B",          "QEMU_GUEST_BASE",  true,  handle_arg_guest_base,
437      "address",    "set guest_base address to 'address'"},
438     {"R",          "QEMU_RESERVED_VA", true,  handle_arg_reserved_va,
439      "size",       "reserve 'size' bytes for guest virtual address space"},
440     {"d",          "QEMU_LOG",         true,  handle_arg_log,
441      "item[,...]", "enable logging of specified items "
442      "(use '-d help' for a list of items)"},
443     {"dfilter",    "QEMU_DFILTER",     true,  handle_arg_dfilter,
444      "range[,...]","filter logging based on address range"},
445     {"D",          "QEMU_LOG_FILENAME", true, handle_arg_log_filename,
446      "logfile",     "write logs to 'logfile' (default stderr)"},
447     {"p",          "QEMU_PAGESIZE",    true,  handle_arg_pagesize,
448      "pagesize",   "set the host page size to 'pagesize'"},
449     {"singlestep", "QEMU_SINGLESTEP",  false, handle_arg_singlestep,
450      "",           "run in singlestep mode"},
451     {"strace",     "QEMU_STRACE",      false, handle_arg_strace,
452      "",           "log system calls"},
453     {"seed",       "QEMU_RAND_SEED",   true,  handle_arg_seed,
454      "",           "Seed for pseudo-random number generator"},
455     {"trace",      "QEMU_TRACE",       true,  handle_arg_trace,
456      "",           "[[enable=]<pattern>][,events=<file>][,file=<file>]"},
457 #ifdef CONFIG_PLUGIN
458     {"plugin",     "QEMU_PLUGIN",      true,  handle_arg_plugin,
459      "",           "[file=]<file>[,<argname>=<argvalue>]"},
460 #endif
461     {"version",    "QEMU_VERSION",     false, handle_arg_version,
462      "",           "display version information and exit"},
463 #if defined(TARGET_XTENSA)
464     {"xtensa-abi-call0", "QEMU_XTENSA_ABI_CALL0", false, handle_arg_abi_call0,
465      "",           "assume CALL0 Xtensa ABI"},
466 #endif
467     {NULL, NULL, false, NULL, NULL, NULL}
468 };
469 
470 static void usage(int exitcode)
471 {
472     const struct qemu_argument *arginfo;
473     int maxarglen;
474     int maxenvlen;
475 
476     printf("usage: qemu-" TARGET_NAME " [options] program [arguments...]\n"
477            "Linux CPU emulator (compiled for " TARGET_NAME " emulation)\n"
478            "\n"
479            "Options and associated environment variables:\n"
480            "\n");
481 
482     /* Calculate column widths. We must always have at least enough space
483      * for the column header.
484      */
485     maxarglen = strlen("Argument");
486     maxenvlen = strlen("Env-variable");
487 
488     for (arginfo = arg_table; arginfo->handle_opt != NULL; arginfo++) {
489         int arglen = strlen(arginfo->argv);
490         if (arginfo->has_arg) {
491             arglen += strlen(arginfo->example) + 1;
492         }
493         if (strlen(arginfo->env) > maxenvlen) {
494             maxenvlen = strlen(arginfo->env);
495         }
496         if (arglen > maxarglen) {
497             maxarglen = arglen;
498         }
499     }
500 
501     printf("%-*s %-*s Description\n", maxarglen+1, "Argument",
502             maxenvlen, "Env-variable");
503 
504     for (arginfo = arg_table; arginfo->handle_opt != NULL; arginfo++) {
505         if (arginfo->has_arg) {
506             printf("-%s %-*s %-*s %s\n", arginfo->argv,
507                    (int)(maxarglen - strlen(arginfo->argv) - 1),
508                    arginfo->example, maxenvlen, arginfo->env, arginfo->help);
509         } else {
510             printf("-%-*s %-*s %s\n", maxarglen, arginfo->argv,
511                     maxenvlen, arginfo->env,
512                     arginfo->help);
513         }
514     }
515 
516     printf("\n"
517            "Defaults:\n"
518            "QEMU_LD_PREFIX  = %s\n"
519            "QEMU_STACK_SIZE = %ld byte\n",
520            interp_prefix,
521            guest_stack_size);
522 
523     printf("\n"
524            "You can use -E and -U options or the QEMU_SET_ENV and\n"
525            "QEMU_UNSET_ENV environment variables to set and unset\n"
526            "environment variables for the target process.\n"
527            "It is possible to provide several variables by separating them\n"
528            "by commas in getsubopt(3) style. Additionally it is possible to\n"
529            "provide the -E and -U options multiple times.\n"
530            "The following lines are equivalent:\n"
531            "    -E var1=val2 -E var2=val2 -U LD_PRELOAD -U LD_DEBUG\n"
532            "    -E var1=val2,var2=val2 -U LD_PRELOAD,LD_DEBUG\n"
533            "    QEMU_SET_ENV=var1=val2,var2=val2 QEMU_UNSET_ENV=LD_PRELOAD,LD_DEBUG\n"
534            "Note that if you provide several changes to a single variable\n"
535            "the last change will stay in effect.\n"
536            "\n"
537            QEMU_HELP_BOTTOM "\n");
538 
539     exit(exitcode);
540 }
541 
542 static int parse_args(int argc, char **argv)
543 {
544     const char *r;
545     int optind;
546     const struct qemu_argument *arginfo;
547 
548     for (arginfo = arg_table; arginfo->handle_opt != NULL; arginfo++) {
549         if (arginfo->env == NULL) {
550             continue;
551         }
552 
553         r = getenv(arginfo->env);
554         if (r != NULL) {
555             arginfo->handle_opt(r);
556         }
557     }
558 
559     optind = 1;
560     for (;;) {
561         if (optind >= argc) {
562             break;
563         }
564         r = argv[optind];
565         if (r[0] != '-') {
566             break;
567         }
568         optind++;
569         r++;
570         if (!strcmp(r, "-")) {
571             break;
572         }
573         /* Treat --foo the same as -foo.  */
574         if (r[0] == '-') {
575             r++;
576         }
577 
578         for (arginfo = arg_table; arginfo->handle_opt != NULL; arginfo++) {
579             if (!strcmp(r, arginfo->argv)) {
580                 if (arginfo->has_arg) {
581                     if (optind >= argc) {
582                         (void) fprintf(stderr,
583                             "qemu: missing argument for option '%s'\n", r);
584                         exit(EXIT_FAILURE);
585                     }
586                     arginfo->handle_opt(argv[optind]);
587                     optind++;
588                 } else {
589                     arginfo->handle_opt(NULL);
590                 }
591                 break;
592             }
593         }
594 
595         /* no option matched the current argv */
596         if (arginfo->handle_opt == NULL) {
597             (void) fprintf(stderr, "qemu: unknown option '%s'\n", r);
598             exit(EXIT_FAILURE);
599         }
600     }
601 
602     if (optind >= argc) {
603         (void) fprintf(stderr, "qemu: no user program specified\n");
604         exit(EXIT_FAILURE);
605     }
606 
607     exec_path = argv[optind];
608 
609     return optind;
610 }
611 
612 int main(int argc, char **argv, char **envp)
613 {
614     struct target_pt_regs regs1, *regs = &regs1;
615     struct image_info info1, *info = &info1;
616     struct linux_binprm bprm;
617     TaskState *ts;
618     CPUArchState *env;
619     CPUState *cpu;
620     int optind;
621     char **target_environ, **wrk;
622     char **target_argv;
623     int target_argc;
624     int i;
625     int ret;
626     int execfd;
627     int log_mask;
628     unsigned long max_reserved_va;
629     bool preserve_argv0;
630 
631     error_init(argv[0]);
632     module_call_init(MODULE_INIT_TRACE);
633     qemu_init_cpu_list();
634     module_call_init(MODULE_INIT_QOM);
635 
636     envlist = envlist_create();
637 
638     /* add current environment into the list */
639     for (wrk = environ; *wrk != NULL; wrk++) {
640         (void) envlist_setenv(envlist, *wrk);
641     }
642 
643     /* Read the stack limit from the kernel.  If it's "unlimited",
644        then we can do little else besides use the default.  */
645     {
646         struct rlimit lim;
647         if (getrlimit(RLIMIT_STACK, &lim) == 0
648             && lim.rlim_cur != RLIM_INFINITY
649             && lim.rlim_cur == (target_long)lim.rlim_cur) {
650             guest_stack_size = lim.rlim_cur;
651         }
652     }
653 
654     cpu_model = NULL;
655 
656     qemu_add_opts(&qemu_trace_opts);
657     qemu_plugin_add_opts();
658 
659     optind = parse_args(argc, argv);
660 
661     log_mask = last_log_mask | (enable_strace ? LOG_STRACE : 0);
662     if (log_mask) {
663         qemu_log_needs_buffers();
664         qemu_set_log(log_mask);
665     }
666 
667     if (!trace_init_backends()) {
668         exit(1);
669     }
670     trace_init_file();
671     qemu_plugin_load_list(&plugins, &error_fatal);
672 
673     /* Zero out regs */
674     memset(regs, 0, sizeof(struct target_pt_regs));
675 
676     /* Zero out image_info */
677     memset(info, 0, sizeof(struct image_info));
678 
679     memset(&bprm, 0, sizeof (bprm));
680 
681     /* Scan interp_prefix dir for replacement files. */
682     init_paths(interp_prefix);
683 
684     init_qemu_uname_release();
685 
686     /*
687      * Manage binfmt-misc open-binary flag
688      */
689     execfd = qemu_getauxval(AT_EXECFD);
690     if (execfd == 0) {
691         execfd = open(exec_path, O_RDONLY);
692         if (execfd < 0) {
693             printf("Error while loading %s: %s\n", exec_path, strerror(errno));
694             _exit(EXIT_FAILURE);
695         }
696     }
697 
698     /*
699      * get binfmt_misc flags
700      */
701     preserve_argv0 = !!(qemu_getauxval(AT_FLAGS) & AT_FLAGS_PRESERVE_ARGV0);
702 
703     /*
704      * Manage binfmt-misc preserve-arg[0] flag
705      *    argv[optind]     full path to the binary
706      *    argv[optind + 1] original argv[0]
707      */
708     if (optind + 1 < argc && preserve_argv0) {
709         optind++;
710     }
711 
712     if (cpu_model == NULL) {
713         cpu_model = cpu_get_model(get_elf_eflags(execfd));
714     }
715     cpu_type = parse_cpu_option(cpu_model);
716 
717     /* init tcg before creating CPUs and to get qemu_host_page_size */
718     {
719         AccelClass *ac = ACCEL_GET_CLASS(current_accel());
720 
721         accel_init_interfaces(ac);
722         ac->init_machine(NULL);
723     }
724     cpu = cpu_create(cpu_type);
725     env = cpu->env_ptr;
726     cpu_reset(cpu);
727     thread_cpu = cpu;
728 
729     /*
730      * Reserving too much vm space via mmap can run into problems
731      * with rlimits, oom due to page table creation, etc.  We will
732      * still try it, if directed by the command-line option, but
733      * not by default.
734      */
735     max_reserved_va = MAX_RESERVED_VA(cpu);
736     if (reserved_va != 0) {
737         if (max_reserved_va && reserved_va > max_reserved_va) {
738             fprintf(stderr, "Reserved virtual address too big\n");
739             exit(EXIT_FAILURE);
740         }
741     } else if (HOST_LONG_BITS == 64 && TARGET_VIRT_ADDR_SPACE_BITS <= 32) {
742         /*
743          * reserved_va must be aligned with the host page size
744          * as it is used with mmap()
745          */
746         reserved_va = max_reserved_va & qemu_host_page_mask;
747     }
748 
749     {
750         Error *err = NULL;
751         if (seed_optarg != NULL) {
752             qemu_guest_random_seed_main(seed_optarg, &err);
753         } else {
754             qcrypto_init(&err);
755         }
756         if (err) {
757             error_reportf_err(err, "cannot initialize crypto: ");
758             exit(1);
759         }
760     }
761 
762     target_environ = envlist_to_environ(envlist, NULL);
763     envlist_free(envlist);
764 
765     /*
766      * Read in mmap_min_addr kernel parameter.  This value is used
767      * When loading the ELF image to determine whether guest_base
768      * is needed.  It is also used in mmap_find_vma.
769      */
770     {
771         FILE *fp;
772 
773         if ((fp = fopen("/proc/sys/vm/mmap_min_addr", "r")) != NULL) {
774             unsigned long tmp;
775             if (fscanf(fp, "%lu", &tmp) == 1 && tmp != 0) {
776                 mmap_min_addr = tmp;
777                 qemu_log_mask(CPU_LOG_PAGE, "host mmap_min_addr=0x%lx\n",
778                               mmap_min_addr);
779             }
780             fclose(fp);
781         }
782     }
783 
784     /*
785      * We prefer to not make NULL pointers accessible to QEMU.
786      * If we're in a chroot with no /proc, fall back to 1 page.
787      */
788     if (mmap_min_addr == 0) {
789         mmap_min_addr = qemu_host_page_size;
790         qemu_log_mask(CPU_LOG_PAGE,
791                       "host mmap_min_addr=0x%lx (fallback)\n",
792                       mmap_min_addr);
793     }
794 
795     /*
796      * Prepare copy of argv vector for target.
797      */
798     target_argc = argc - optind;
799     target_argv = calloc(target_argc + 1, sizeof (char *));
800     if (target_argv == NULL) {
801         (void) fprintf(stderr, "Unable to allocate memory for target_argv\n");
802         exit(EXIT_FAILURE);
803     }
804 
805     /*
806      * If argv0 is specified (using '-0' switch) we replace
807      * argv[0] pointer with the given one.
808      */
809     i = 0;
810     if (argv0 != NULL) {
811         target_argv[i++] = strdup(argv0);
812     }
813     for (; i < target_argc; i++) {
814         target_argv[i] = strdup(argv[optind + i]);
815     }
816     target_argv[target_argc] = NULL;
817 
818     ts = g_new0(TaskState, 1);
819     init_task_state(ts);
820     /* build Task State */
821     ts->info = info;
822     ts->bprm = &bprm;
823     cpu->opaque = ts;
824     task_settid(ts);
825 
826     fd_trans_init();
827 
828     ret = loader_exec(execfd, exec_path, target_argv, target_environ, regs,
829         info, &bprm);
830     if (ret != 0) {
831         printf("Error while loading %s: %s\n", exec_path, strerror(-ret));
832         _exit(EXIT_FAILURE);
833     }
834 
835     for (wrk = target_environ; *wrk; wrk++) {
836         g_free(*wrk);
837     }
838 
839     g_free(target_environ);
840 
841     if (qemu_loglevel_mask(CPU_LOG_PAGE)) {
842         qemu_log("guest_base  %p\n", (void *)guest_base);
843         log_page_dump("binary load");
844 
845         qemu_log("start_brk   0x" TARGET_ABI_FMT_lx "\n", info->start_brk);
846         qemu_log("end_code    0x" TARGET_ABI_FMT_lx "\n", info->end_code);
847         qemu_log("start_code  0x" TARGET_ABI_FMT_lx "\n", info->start_code);
848         qemu_log("start_data  0x" TARGET_ABI_FMT_lx "\n", info->start_data);
849         qemu_log("end_data    0x" TARGET_ABI_FMT_lx "\n", info->end_data);
850         qemu_log("start_stack 0x" TARGET_ABI_FMT_lx "\n", info->start_stack);
851         qemu_log("brk         0x" TARGET_ABI_FMT_lx "\n", info->brk);
852         qemu_log("entry       0x" TARGET_ABI_FMT_lx "\n", info->entry);
853         qemu_log("argv_start  0x" TARGET_ABI_FMT_lx "\n", info->arg_start);
854         qemu_log("env_start   0x" TARGET_ABI_FMT_lx "\n",
855                  info->arg_end + (abi_ulong)sizeof(abi_ulong));
856         qemu_log("auxv_start  0x" TARGET_ABI_FMT_lx "\n", info->saved_auxv);
857     }
858 
859     target_set_brk(info->brk);
860     syscall_init();
861     signal_init();
862 
863     /* Now that we've loaded the binary, GUEST_BASE is fixed.  Delay
864        generating the prologue until now so that the prologue can take
865        the real value of GUEST_BASE into account.  */
866     tcg_prologue_init(tcg_ctx);
867 
868     target_cpu_copy_regs(env, regs);
869 
870     if (gdbstub) {
871         if (gdbserver_start(gdbstub) < 0) {
872             fprintf(stderr, "qemu: could not open gdbserver on %s\n",
873                     gdbstub);
874             exit(EXIT_FAILURE);
875         }
876         gdb_handlesig(cpu, 0);
877     }
878     cpu_loop(env);
879     /* never exits */
880     return 0;
881 }
882