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