summaryrefslogtreecommitdiffstats
path: root/arch/um/kernel/um_arch.c
blob: 7a9820797eae24c1523da6415bc23fd43ddb8a36 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
 */

#include <linux/cpu.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/ctype.h>
#include <linux/module.h>
#include <linux/panic_notifier.h>
#include <linux/seq_file.h>
#include <linux/string.h>
#include <linux/utsname.h>
#include <linux/sched.h>
#include <linux/sched/task.h>
#include <linux/kmsg_dump.h>
#include <linux/suspend.h>
#include <linux/random.h>

#include <asm/processor.h>
#include <asm/cpufeature.h>
#include <asm/sections.h>
#include <asm/setup.h>
#include <as-layout.h>
#include <arch.h>
#include <init.h>
#include <kern.h>
#include <kern_util.h>
#include <mem_user.h>
#include <os.h>

#include "um_arch.h"

#define DEFAULT_COMMAND_LINE_ROOT "root=98:0"
#define DEFAULT_COMMAND_LINE_CONSOLE "console=tty0"

/* Changed in add_arg and setup_arch, which run before SMP is started */
static char __initdata command_line[COMMAND_LINE_SIZE] = { 0 };

static void __init add_arg(char *arg)
{
	if (strlen(command_line) + strlen(arg) + 1 > COMMAND_LINE_SIZE) {
		os_warn("add_arg: Too many command line arguments!\n");
		exit(1);
	}
	if (strlen(command_line) > 0)
		strcat(command_line, " ");
	strcat(command_line, arg);
}

/*
 * These fields are initialized at boot time and not changed.
 * XXX This structure is used only in the non-SMP case.  Maybe this
 * should be moved to smp.c.
 */
struct cpuinfo_um boot_cpu_data = {
	.loops_per_jiffy	= 0,
	.ipi_pipe		= { -1, -1 },
	.cache_alignment	= L1_CACHE_BYTES,
	.x86_capability		= { 0 }
};

EXPORT_SYMBOL(boot_cpu_data);

union thread_union cpu0_irqstack
	__section(".data..init_irqstack") =
		{ .thread_info = INIT_THREAD_INFO(init_task) };

/* Changed in setup_arch, which is called in early boot */
static char host_info[(__NEW_UTS_LEN + 1) * 5];

static int show_cpuinfo(struct seq_file *m, void *v)
{
	int i = 0;

	seq_printf(m, "processor\t: %d\n", i);
	seq_printf(m, "vendor_id\t: User Mode Linux\n");
	seq_printf(m, "model name\t: UML\n");
	seq_printf(m, "mode\t\t: skas\n");
	seq_printf(m, "host\t\t: %s\n", host_info);
	seq_printf(m, "fpu\t\t: %s\n", cpu_has(&boot_cpu_data, X86_FEATURE_FPU) ? "yes" : "no");
	seq_printf(m, "flags\t\t:");
	for (i = 0; i < 32*NCAPINTS; i++)
		if (cpu_has(&boot_cpu_data, i) && (x86_cap_flags[i] != NULL))
			seq_printf(m, " %s", x86_cap_flags[i]);
	seq_printf(m, "\n");
	seq_printf(m, "cache_alignment\t: %d\n", boot_cpu_data.cache_alignment);
	seq_printf(m, "bogomips\t: %lu.%02lu\n",
		   loops_per_jiffy/(500000/HZ),
		   (loops_per_jiffy/(5000/HZ)) % 100);


	return 0;
}

static void *c_start(struct seq_file *m, loff_t *pos)
{
	return *pos < nr_cpu_ids ? &boot_cpu_data + *pos : NULL;
}

static void *c_next(struct seq_file *m, void *v, loff_t *pos)
{
	++*pos;
	return c_start(m, pos);
}

static void c_stop(struct seq_file *m, void *v)
{
}

const struct seq_operations cpuinfo_op = {
	.start	= c_start,
	.next	= c_next,
	.stop	= c_stop,
	.show	= show_cpuinfo,
};

/* Set in linux_main */
unsigned long uml_physmem;
EXPORT_SYMBOL(uml_physmem);

unsigned long uml_reserved; /* Also modified in mem_init */
unsigned long start_vm;
unsigned long end_vm;

/* Set in uml_ncpus_setup */
int ncpus = 1;

/* Set in early boot */
static int have_root __initdata;
static int have_console __initdata;

/* Set in uml_mem_setup and modified in linux_main */
long long physmem_size = 64 * 1024 * 1024;
EXPORT_SYMBOL(physmem_size);

static const char *usage_string =
"User Mode Linux v%s\n"
"	available at http://user-mode-linux.sourceforge.net/\n\n";

static int __init uml_version_setup(char *line, int *add)
{
	/* Explicitly use printf() to show version in stdout */
	printf("%s\n", init_utsname()->release);
	exit(0);

	return 0;
}

__uml_setup("--version", uml_version_setup,
"--version\n"
"    Prints the version number of the kernel.\n\n"
);

static int __init uml_root_setup(char *line, int *add)
{
	have_root = 1;
	return 0;
}

__uml_setup("root=", uml_root_setup,
"root=<file containing the root fs>\n"
"    This is actually used by the generic kernel in exactly the same\n"
"    way as in any other kernel. If you configure a number of block\n"
"    devices and want to boot off something other than ubd0, you \n"
"    would use something like:\n"
"        root=/dev/ubd5\n\n"
);

static int __init no_skas_debug_setup(char *line, int *add)
{
	os_warn("'debug' is not necessary to gdb UML in skas mode - run\n");
	os_warn("'gdb linux'\n");

	return 0;
}

__uml_setup("debug", no_skas_debug_setup,
"debug\n"
"    this flag is not needed to run gdb on UML in skas mode\n\n"
);

static int __init uml_console_setup(char *line, int *add)
{
	have_console = 1;
	return 0;
}

__uml_setup("console=", uml_console_setup,
"console=<preferred console>\n"
"    Specify the preferred console output driver\n\n"
);

static int __init Usage(char *line, int *add)
{
	const char **p;

	printf(usage_string, init_utsname()->release);
	p = &__uml_help_start;
	/* Explicitly use printf() to show help in stdout */
	while (p < &__uml_help_end) {
		printf("%s", *p);
		p++;
	}
	exit(0);
	return 0;
}

__uml_setup("--help", Usage,
"--help\n"
"    Prints this message.\n\n"
);

static void __init uml_checksetup(char *line, int *add)
{
	struct uml_param *p;

	p = &__uml_setup_start;
	while (p < &__uml_setup_end) {
		size_t n;

		n = strlen(p->str);
		if (!strncmp(line, p->str, n) && p->setup_func(line + n, add))
			return;
		p++;
	}
}

static void __init uml_postsetup(void)
{
	initcall_t *p;

	p = &__uml_postsetup_start;
	while (p < &__uml_postsetup_end) {
		(*p)();
		p++;
	}
	return;
}

static int panic_exit(struct notifier_block *self, unsigned long unused1,
		      void *unused2)
{
	kmsg_dump(KMSG_DUMP_PANIC);
	bust_spinlocks(1);
	bust_spinlocks(0);
	uml_exitcode = 1;
	os_dump_core();

	return NOTIFY_DONE;
}

static struct notifier_block panic_exit_notifier = {
	.notifier_call	= panic_exit,
	.priority	= INT_MAX - 1, /* run as 2nd notifier, won't return */
};

void uml_finishsetup(void)
{
	atomic_notifier_chain_register(&panic_notifier_list,
				       &panic_exit_notifier);

	uml_postsetup();

	new_thread_handler();
}

/* Set during early boot */
unsigned long stub_start;
unsigned long task_size;
EXPORT_SYMBOL(task_size);

unsigned long host_task_size;

unsigned long brk_start;
unsigned long end_iomem;
EXPORT_SYMBOL(end_iomem);

#define MIN_VMALLOC (32 * 1024 * 1024)

static void parse_host_cpu_flags(char *line)
{
	int i;
	for (i = 0; i < 32*NCAPINTS; i++) {
		if ((x86_cap_flags[i] != NULL) && strstr(line, x86_cap_flags[i]))
			set_cpu_cap(&boot_cpu_data, i);
	}
}
static void parse_cache_line(char *line)
{
	long res;
	char *to_parse = strstr(line, ":");
	if (to_parse) {
		to_parse++;
		while (*to_parse != 0 && isspace(*to_parse)) {
			to_parse++;
		}
		if (kstrtoul(to_parse, 10, &res) == 0 && is_power_of_2(res))
			boot_cpu_data.cache_alignment = res;
		else
			boot_cpu_data.cache_alignment = L1_CACHE_BYTES;
	}
}

int __init linux_main(int argc, char **argv)
{
	unsigned long avail, diff;
	unsigned long virtmem_size, max_physmem;
	unsigned long stack;
	unsigned int i;
	int add;

	for (i = 1; i < argc; i++) {
		if ((i == 1) && (argv[i][0] == ' '))
			continue;
		add = 1;
		uml_checksetup(argv[i], &add);
		if (add)
			add_arg(argv[i]);
	}
	if (have_root == 0)
		add_arg(DEFAULT_COMMAND_LINE_ROOT);

	if (have_console == 0)
		add_arg(DEFAULT_COMMAND_LINE_CONSOLE);

	host_task_size = os_get_top_address();
	/* reserve a few pages for the stubs (taking care of data alignment) */
	/* align the data portion */
	BUILD_BUG_ON(!is_power_of_2(STUB_DATA_PAGES));
	stub_start = (host_task_size - 1) & ~(STUB_DATA_PAGES * PAGE_SIZE - 1);
	/* another page for the code portion */
	stub_start -= PAGE_SIZE;
	host_task_size = stub_start;

	/*
	 * TASK_SIZE needs to be PGDIR_SIZE aligned or else exit_mmap craps
	 * out
	 */
	task_size = host_task_size & PGDIR_MASK;

	/* OS sanity checks that need to happen before the kernel runs */
	os_early_checks();

	get_host_cpu_features(parse_host_cpu_flags, parse_cache_line);

	brk_start = (unsigned long) sbrk(0);

	/*
	 * Increase physical memory size for exec-shield users
	 * so they actually get what they asked for. This should
	 * add zero for non-exec shield users
	 */

	diff = UML_ROUND_UP(brk_start) - UML_ROUND_UP(&_end);
	if (diff > 1024 * 1024) {
		os_info("Adding %ld bytes to physical memory to account for "
			"exec-shield gap\n", diff);
		physmem_size += UML_ROUND_UP(brk_start) - UML_ROUND_UP(&_end);
	}

	uml_physmem = (unsigned long) __binary_start & PAGE_MASK;

	/* Reserve up to 4M after the current brk */
	uml_reserved = ROUND_4M(brk_start) + (1 << 22);

	setup_machinename(init_utsname()->machine);

	highmem = 0;
	iomem_size = (iomem_size + PAGE_SIZE - 1) & PAGE_MASK;
	max_physmem = TASK_SIZE - uml_physmem - iomem_size - MIN_VMALLOC;

	/*
	 * Zones have to begin on a 1 << MAX_PAGE_ORDER page boundary,
	 * so this makes sure that's true for highmem
	 */
	max_physmem &= ~((1 << (PAGE_SHIFT + MAX_PAGE_ORDER)) - 1);
	if (physmem_size + iomem_size > max_physmem) {
		highmem = physmem_size + iomem_size - max_physmem;
		physmem_size -= highmem;
	}

	high_physmem = uml_physmem + physmem_size;
	end_iomem = high_physmem + iomem_size;
	high_memory = (void *) end_iomem;

	start_vm = VMALLOC_START;

	virtmem_size = physmem_size;
	stack = (unsigned long) argv;
	stack &= ~(1024 * 1024 - 1);
	avail = stack - start_vm;
	if (physmem_size > avail)
		virtmem_size = avail;
	end_vm = start_vm + virtmem_size;

	if (virtmem_size < physmem_size)
		os_info("Kernel virtual memory size shrunk to %lu bytes\n",
			virtmem_size);

	os_flush_stdout();

	return start_uml();
}

int __init __weak read_initrd(void)
{
	return 0;
}

void __init setup_arch(char **cmdline_p)
{
	u8 rng_seed[32];

	stack_protections((unsigned long) &init_thread_info);
	setup_physmem(uml_physmem, uml_reserved, physmem_size, highmem);
	mem_total_pages(physmem_size, iomem_size, highmem);
	uml_dtb_init();
	read_initrd();

	paging_init();
	strscpy(boot_command_line, command_line, COMMAND_LINE_SIZE);
	*cmdline_p = command_line;
	setup_hostinfo(host_info, sizeof host_info);

	if (os_getrandom(rng_seed, sizeof(rng_seed), 0) == sizeof(rng_seed)) {
		add_bootloader_randomness(rng_seed, sizeof(rng_seed));
		memzero_explicit(rng_seed, sizeof(rng_seed));
	}
}

void __init arch_cpu_finalize_init(void)
{
	arch_check_bugs();
	os_check_bugs();
}

void apply_seal_endbr(s32 *start, s32 *end)
{
}

void apply_retpolines(s32 *start, s32 *end)
{
}

void apply_returns(s32 *start, s32 *end)
{
}

void apply_fineibt(s32 *start_retpoline, s32 *end_retpoline,
		   s32 *start_cfi, s32 *end_cfi)
{
}

void apply_alternatives(struct alt_instr *start, struct alt_instr *end)
{
}

void *text_poke(void *addr, const void *opcode, size_t len)
{
	/*
	 * In UML, the only reference to this function is in
	 * apply_relocate_add(), which shouldn't ever actually call this
	 * because UML doesn't have live patching.
	 */
	WARN_ON(1);

	return memcpy(addr, opcode, len);
}

void text_poke_sync(void)
{
}

void uml_pm_wake(void)
{
	pm_system_wakeup();
}

#ifdef CONFIG_PM_SLEEP
static int um_suspend_valid(suspend_state_t state)
{
	return state == PM_SUSPEND_MEM;
}

static int um_suspend_prepare(void)
{
	um_irqs_suspend();
	return 0;
}

static int um_suspend_enter(suspend_state_t state)
{
	if (WARN_ON(state != PM_SUSPEND_MEM))
		return -EINVAL;

	/*
	 * This is identical to the idle sleep, but we've just
	 * (during suspend) turned off all interrupt sources
	 * except for the ones we want, so now we can only wake
	 * up on something we actually want to wake up on. All
	 * timing has also been suspended.
	 */
	um_idle_sleep();
	return 0;
}

static void um_suspend_finish(void)
{
	um_irqs_resume();
}

const struct platform_suspend_ops um_suspend_ops = {
	.valid = um_suspend_valid,
	.prepare = um_suspend_prepare,
	.enter = um_suspend_enter,
	.finish = um_suspend_finish,
};

static int init_pm_wake_signal(void)
{
	/*
	 * In external time-travel mode we can't use signals to wake up
	 * since that would mess with the scheduling. We'll have to do
	 * some additional work to support wakeup on virtio devices or
	 * similar, perhaps implementing a fake RTC controller that can
	 * trigger wakeup (and request the appropriate scheduling from
	 * the external scheduler when going to suspend.)
	 */
	if (time_travel_mode != TT_MODE_EXTERNAL)
		register_pm_wake_signal();

	suspend_set_ops(&um_suspend_ops);

	return 0;
}

late_initcall(init_pm_wake_signal);
#endif