1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
4 */
5
6 #include <linux/cpu.h>
7 #include <linux/delay.h>
8 #include <linux/init.h>
9 #include <linux/mm.h>
10 #include <linux/ctype.h>
11 #include <linux/module.h>
12 #include <linux/panic_notifier.h>
13 #include <linux/seq_file.h>
14 #include <linux/string.h>
15 #include <linux/utsname.h>
16 #include <linux/sched.h>
17 #include <linux/sched/task.h>
18 #include <linux/kmsg_dump.h>
19 #include <linux/suspend.h>
20 #include <linux/random.h>
21
22 #include <asm/processor.h>
23 #include <asm/cpufeature.h>
24 #include <asm/sections.h>
25 #include <asm/setup.h>
26 #include <asm/text-patching.h>
27 #include <as-layout.h>
28 #include <arch.h>
29 #include <init.h>
30 #include <kern.h>
31 #include <kern_util.h>
32 #include <mem_user.h>
33 #include <os.h>
34
35 #include "um_arch.h"
36
37 #define DEFAULT_COMMAND_LINE_ROOT "root=98:0"
38 #define DEFAULT_COMMAND_LINE_CONSOLE "console=tty0"
39
40 /* Changed in add_arg and setup_arch, which run before SMP is started */
41 static char __initdata command_line[COMMAND_LINE_SIZE] = { 0 };
42
43 static void __init add_arg(char *arg)
44 {
45 if (strlen(command_line) + strlen(arg) + 1 > COMMAND_LINE_SIZE) {
46 os_warn("add_arg: Too many command line arguments!\n");
47 exit(1);
48 }
49 if (strlen(command_line) > 0)
50 strcat(command_line, " ");
51 strcat(command_line, arg);
52 }
53
54 /*
55 * These fields are initialized at boot time and not changed.
56 * XXX This structure is used only in the non-SMP case. Maybe this
57 * should be moved to smp.c.
58 */
59 struct cpuinfo_um boot_cpu_data = {
60 .loops_per_jiffy = 0,
61 .ipi_pipe = { -1, -1 },
62 .cache_alignment = L1_CACHE_BYTES,
63 .x86_capability = { 0 }
64 };
65
66 EXPORT_SYMBOL(boot_cpu_data);
67
68 union thread_union cpu0_irqstack
69 __section(".data..init_irqstack") =
70 { .thread_info = INIT_THREAD_INFO(init_task) };
71
72 /* Changed in setup_arch, which is called in early boot */
73 static char host_info[(__NEW_UTS_LEN + 1) * 5];
74
75 static int show_cpuinfo(struct seq_file *m, void *v)
76 {
77 int i = 0;
78
79 seq_printf(m, "processor\t: %d\n", i);
80 seq_printf(m, "vendor_id\t: User Mode Linux\n");
81 seq_printf(m, "model name\t: UML\n");
82 seq_printf(m, "mode\t\t: skas\n");
83 seq_printf(m, "host\t\t: %s\n", host_info);
84 seq_printf(m, "fpu\t\t: %s\n", cpu_has(&boot_cpu_data, X86_FEATURE_FPU) ? "yes" : "no");
85 seq_printf(m, "flags\t\t:");
86 for (i = 0; i < 32*NCAPINTS; i++)
87 if (cpu_has(&boot_cpu_data, i) && (x86_cap_flags[i] != NULL))
88 seq_printf(m, " %s", x86_cap_flags[i]);
89 seq_printf(m, "\n");
90 seq_printf(m, "cache_alignment\t: %d\n", boot_cpu_data.cache_alignment);
91 seq_printf(m, "bogomips\t: %lu.%02lu\n",
92 loops_per_jiffy/(500000/HZ),
93 (loops_per_jiffy/(5000/HZ)) % 100);
94
95
96 return 0;
97 }
98
99 static void *c_start(struct seq_file *m, loff_t *pos)
100 {
101 return *pos < nr_cpu_ids ? &boot_cpu_data + *pos : NULL;
102 }
103
104 static void *c_next(struct seq_file *m, void *v, loff_t *pos)
105 {
106 ++*pos;
107 return c_start(m, pos);
108 }
109
110 static void c_stop(struct seq_file *m, void *v)
111 {
112 }
113
114 const struct seq_operations cpuinfo_op = {
115 .start = c_start,
116 .next = c_next,
117 .stop = c_stop,
118 .show = show_cpuinfo,
119 };
120
121 /* Set in linux_main */
122 unsigned long uml_physmem;
123 EXPORT_SYMBOL(uml_physmem);
124
125 unsigned long uml_reserved; /* Also modified in mem_init */
126 unsigned long start_vm;
127 unsigned long end_vm;
128
129 /* Set in early boot */
130 static int have_root __initdata;
131 static int have_console __initdata;
132
133 /* Set in uml_mem_setup and modified in linux_main */
134 long long physmem_size = 64 * 1024 * 1024;
135 EXPORT_SYMBOL(physmem_size);
136
137 static const char *usage_string =
138 "User Mode Linux v%s\n"
139 " available at http://user-mode-linux.sourceforge.net/\n\n";
140
141 static int __init uml_version_setup(char *line, int *add)
142 {
143 /* Explicitly use printf() to show version in stdout */
144 printf("%s\n", init_utsname()->release);
145 exit(0);
146
147 return 0;
148 }
149
150 __uml_setup("--version", uml_version_setup,
151 "--version\n"
152 " Prints the version number of the kernel.\n\n"
153 );
154
155 static int __init uml_root_setup(char *line, int *add)
156 {
157 have_root = 1;
158 return 0;
159 }
160
161 __uml_setup("root=", uml_root_setup,
162 "root=<file containing the root fs>\n"
163 " This is actually used by the generic kernel in exactly the same\n"
164 " way as in any other kernel. If you configure a number of block\n"
165 " devices and want to boot off something other than ubd0, you \n"
166 " would use something like:\n"
167 " root=/dev/ubd5\n\n"
168 );
169
170 static int __init no_skas_debug_setup(char *line, int *add)
171 {
172 os_warn("'debug' is not necessary to gdb UML in skas mode - run\n");
173 os_warn("'gdb linux'\n");
174
175 return 0;
176 }
177
178 __uml_setup("debug", no_skas_debug_setup,
179 "debug\n"
180 " this flag is not needed to run gdb on UML in skas mode\n\n"
181 );
182
183 static int __init uml_console_setup(char *line, int *add)
184 {
185 have_console = 1;
186 return 0;
187 }
188
189 __uml_setup("console=", uml_console_setup,
190 "console=<preferred console>\n"
191 " Specify the preferred console output driver\n\n"
192 );
193
194 static int __init Usage(char *line, int *add)
195 {
196 const char **p;
197
198 printf(usage_string, init_utsname()->release);
199 p = &__uml_help_start;
200 /* Explicitly use printf() to show help in stdout */
201 while (p < &__uml_help_end) {
202 printf("%s", *p);
203 p++;
204 }
205 exit(0);
206 return 0;
207 }
208
209 __uml_setup("--help", Usage,
210 "--help\n"
211 " Prints this message.\n\n"
212 );
213
214 static void __init uml_checksetup(char *line, int *add)
215 {
216 struct uml_param *p;
217
218 p = &__uml_setup_start;
219 while (p < &__uml_setup_end) {
220 size_t n;
221
222 n = strlen(p->str);
223 if (!strncmp(line, p->str, n) && p->setup_func(line + n, add))
224 return;
225 p++;
226 }
227 }
228
229 static void __init uml_postsetup(void)
230 {
231 initcall_t *p;
232
233 p = &__uml_postsetup_start;
234 while (p < &__uml_postsetup_end) {
235 (*p)();
236 p++;
237 }
238 return;
239 }
240
241 static int panic_exit(struct notifier_block *self, unsigned long unused1,
242 void *unused2)
243 {
244 kmsg_dump(KMSG_DUMP_PANIC);
245 bust_spinlocks(1);
246 bust_spinlocks(0);
247 uml_exitcode = 1;
248 os_dump_core();
249
250 return NOTIFY_DONE;
251 }
252
253 static struct notifier_block panic_exit_notifier = {
254 .notifier_call = panic_exit,
255 .priority = INT_MAX - 1, /* run as 2nd notifier, won't return */
256 };
257
258 void uml_finishsetup(void)
259 {
260 atomic_notifier_chain_register(&panic_notifier_list,
261 &panic_exit_notifier);
262
263 uml_postsetup();
264
265 new_thread_handler();
266 }
267
268 /* Set during early boot */
269 unsigned long stub_start;
270 unsigned long task_size;
271 EXPORT_SYMBOL(task_size);
272
273 unsigned long host_task_size;
274
275 unsigned long brk_start;
276 unsigned long end_iomem;
277 EXPORT_SYMBOL(end_iomem);
278
279 #define MIN_VMALLOC (32 * 1024 * 1024)
280
281 static void parse_host_cpu_flags(char *line)
282 {
283 int i;
284 for (i = 0; i < 32*NCAPINTS; i++) {
285 if ((x86_cap_flags[i] != NULL) && strstr(line, x86_cap_flags[i]))
286 set_cpu_cap(&boot_cpu_data, i);
287 }
288 }
289 static void parse_cache_line(char *line)
290 {
291 long res;
292 char *to_parse = strstr(line, ":");
293 if (to_parse) {
294 to_parse++;
295 while (*to_parse != 0 && isspace(*to_parse)) {
296 to_parse++;
297 }
298 if (kstrtoul(to_parse, 10, &res) == 0 && is_power_of_2(res))
299 boot_cpu_data.cache_alignment = res;
300 else
301 boot_cpu_data.cache_alignment = L1_CACHE_BYTES;
302 }
303 }
304
305 int __init linux_main(int argc, char **argv)
306 {
307 unsigned long avail, diff;
308 unsigned long virtmem_size, max_physmem;
309 unsigned long stack;
310 unsigned int i;
311 int add;
312
313 for (i = 1; i < argc; i++) {
314 if ((i == 1) && (argv[i][0] == ' '))
315 continue;
316 add = 1;
317 uml_checksetup(argv[i], &add);
318 if (add)
319 add_arg(argv[i]);
320 }
321 if (have_root == 0)
322 add_arg(DEFAULT_COMMAND_LINE_ROOT);
323
324 if (have_console == 0)
325 add_arg(DEFAULT_COMMAND_LINE_CONSOLE);
326
327 host_task_size = os_get_top_address();
328 /* reserve a few pages for the stubs (taking care of data alignment) */
329 /* align the data portion */
330 BUILD_BUG_ON(!is_power_of_2(STUB_DATA_PAGES));
331 stub_start = (host_task_size - 1) & ~(STUB_DATA_PAGES * PAGE_SIZE - 1);
332 /* another page for the code portion */
333 stub_start -= PAGE_SIZE;
334 host_task_size = stub_start;
335
336 /*
337 * TASK_SIZE needs to be PGDIR_SIZE aligned or else exit_mmap craps
338 * out
339 */
340 task_size = host_task_size & PGDIR_MASK;
341
342 /* OS sanity checks that need to happen before the kernel runs */
343 os_early_checks();
344
345 get_host_cpu_features(parse_host_cpu_flags, parse_cache_line);
346
347 brk_start = (unsigned long) sbrk(0);
348
349 /*
350 * Increase physical memory size for exec-shield users
351 * so they actually get what they asked for. This should
352 * add zero for non-exec shield users
353 */
354
355 diff = UML_ROUND_UP(brk_start) - UML_ROUND_UP(&_end);
356 if (diff > 1024 * 1024) {
357 os_info("Adding %ld bytes to physical memory to account for "
358 "exec-shield gap\n", diff);
359 physmem_size += UML_ROUND_UP(brk_start) - UML_ROUND_UP(&_end);
360 }
361
362 uml_physmem = (unsigned long) __binary_start & PAGE_MASK;
363
364 /* Reserve up to 4M after the current brk */
365 uml_reserved = ROUND_4M(brk_start) + (1 << 22);
366
367 setup_machinename(init_utsname()->machine);
368
369 highmem = 0;
370 iomem_size = (iomem_size + PAGE_SIZE - 1) & PAGE_MASK;
371 max_physmem = TASK_SIZE - uml_physmem - iomem_size - MIN_VMALLOC;
372
373 /*
374 * Zones have to begin on a 1 << MAX_PAGE_ORDER page boundary,
375 * so this makes sure that's true for highmem
376 */
377 max_physmem &= ~((1 << (PAGE_SHIFT + MAX_PAGE_ORDER)) - 1);
378 if (physmem_size + iomem_size > max_physmem) {
379 highmem = physmem_size + iomem_size - max_physmem;
380 physmem_size -= highmem;
381 }
382
383 high_physmem = uml_physmem + physmem_size;
384 end_iomem = high_physmem + iomem_size;
385 high_memory = (void *) end_iomem;
386
387 start_vm = VMALLOC_START;
388
389 virtmem_size = physmem_size;
390 stack = (unsigned long) argv;
391 stack &= ~(1024 * 1024 - 1);
392 avail = stack - start_vm;
393 if (physmem_size > avail)
394 virtmem_size = avail;
395 end_vm = start_vm + virtmem_size;
396
397 if (virtmem_size < physmem_size)
398 os_info("Kernel virtual memory size shrunk to %lu bytes\n",
399 virtmem_size);
400
401 os_flush_stdout();
402
403 return start_uml();
404 }
405
406 int __init __weak read_initrd(void)
407 {
408 return 0;
409 }
410
411 void __init setup_arch(char **cmdline_p)
412 {
413 u8 rng_seed[32];
414
415 stack_protections((unsigned long) &init_thread_info);
416 setup_physmem(uml_physmem, uml_reserved, physmem_size, highmem);
417 mem_total_pages(physmem_size, iomem_size, highmem);
418 uml_dtb_init();
419 read_initrd();
420
421 paging_init();
422 strscpy(boot_command_line, command_line, COMMAND_LINE_SIZE);
423 *cmdline_p = command_line;
424 setup_hostinfo(host_info, sizeof host_info);
425
426 if (os_getrandom(rng_seed, sizeof(rng_seed), 0) == sizeof(rng_seed)) {
427 add_bootloader_randomness(rng_seed, sizeof(rng_seed));
428 memzero_explicit(rng_seed, sizeof(rng_seed));
429 }
430 }
431
432 void __init arch_cpu_finalize_init(void)
433 {
434 arch_check_bugs();
435 os_check_bugs();
436 }
437
438 void apply_seal_endbr(s32 *start, s32 *end)
439 {
440 }
441
442 void apply_retpolines(s32 *start, s32 *end)
443 {
444 }
445
446 void apply_returns(s32 *start, s32 *end)
447 {
448 }
449
450 void apply_fineibt(s32 *start_retpoline, s32 *end_retpoline,
451 s32 *start_cfi, s32 *end_cfi)
452 {
453 }
454
455 void apply_alternatives(struct alt_instr *start, struct alt_instr *end)
456 {
457 }
458
459 void *text_poke(void *addr, const void *opcode, size_t len)
460 {
461 /*
462 * In UML, the only reference to this function is in
463 * apply_relocate_add(), which shouldn't ever actually call this
464 * because UML doesn't have live patching.
465 */
466 WARN_ON(1);
467
468 return memcpy(addr, opcode, len);
469 }
470
471 void text_poke_sync(void)
472 {
473 }
474
475 void uml_pm_wake(void)
476 {
477 pm_system_wakeup();
478 }
479
480 #ifdef CONFIG_PM_SLEEP
481 static int um_suspend_valid(suspend_state_t state)
482 {
483 return state == PM_SUSPEND_MEM;
484 }
485
486 static int um_suspend_prepare(void)
487 {
488 um_irqs_suspend();
489 return 0;
490 }
491
492 static int um_suspend_enter(suspend_state_t state)
493 {
494 if (WARN_ON(state != PM_SUSPEND_MEM))
495 return -EINVAL;
496
497 /*
498 * This is identical to the idle sleep, but we've just
499 * (during suspend) turned off all interrupt sources
500 * except for the ones we want, so now we can only wake
501 * up on something we actually want to wake up on. All
502 * timing has also been suspended.
503 */
504 um_idle_sleep();
505 return 0;
506 }
507
508 static void um_suspend_finish(void)
509 {
510 um_irqs_resume();
511 }
512
513 const struct platform_suspend_ops um_suspend_ops = {
514 .valid = um_suspend_valid,
515 .prepare = um_suspend_prepare,
516 .enter = um_suspend_enter,
517 .finish = um_suspend_finish,
518 };
519
520 static int init_pm_wake_signal(void)
521 {
522 /*
523 * In external time-travel mode we can't use signals to wake up
524 * since that would mess with the scheduling. We'll have to do
525 * some additional work to support wakeup on virtio devices or
526 * similar, perhaps implementing a fake RTC controller that can
527 * trigger wakeup (and request the appropriate scheduling from
528 * the external scheduler when going to suspend.)
529 */
530 if (time_travel_mode != TT_MODE_EXTERNAL)
531 register_pm_wake_signal();
532
533 suspend_set_ops(&um_suspend_ops);
534
535 return 0;
536 }
537
538 late_initcall(init_pm_wake_signal);
539 #endif
540
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