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/module.h>
11 #include <linux/seq_file.h>
12 #include <linux/string.h>
13 #include <linux/utsname.h>
14 #include <linux/sched.h>
15 #include <linux/sched/task.h>
16 #include <linux/kmsg_dump.h>
17 #include <linux/suspend.h>
18
19 #include <asm/processor.h>
20 #include <asm/sections.h>
21 #include <asm/setup.h>
22 #include <as-layout.h>
23 #include <arch.h>
24 #include <init.h>
25 #include <kern.h>
26 #include <kern_util.h>
27 #include <mem_user.h>
28 #include <os.h>
29
30 #define DEFAULT_COMMAND_LINE "root=98:0"
31
32 /* Changed in add_arg and setup_arch, which run before SMP is started */
33 static char __initdata command_line[COMMAND_LINE_SIZE] = { 0 };
34
add_arg(char * arg)35 static void __init add_arg(char *arg)
36 {
37 if (strlen(command_line) + strlen(arg) + 1 > COMMAND_LINE_SIZE) {
38 os_warn("add_arg: Too many command line arguments!\n");
39 exit(1);
40 }
41 if (strlen(command_line) > 0)
42 strcat(command_line, " ");
43 strcat(command_line, arg);
44 }
45
46 /*
47 * These fields are initialized at boot time and not changed.
48 * XXX This structure is used only in the non-SMP case. Maybe this
49 * should be moved to smp.c.
50 */
51 struct cpuinfo_um boot_cpu_data = {
52 .loops_per_jiffy = 0,
53 .ipi_pipe = { -1, -1 }
54 };
55
56 union thread_union cpu0_irqstack
57 __section(".data..init_irqstack") =
58 { .thread_info = INIT_THREAD_INFO(init_task) };
59
60 /* Changed in setup_arch, which is called in early boot */
61 static char host_info[(__NEW_UTS_LEN + 1) * 5];
62
show_cpuinfo(struct seq_file * m,void * v)63 static int show_cpuinfo(struct seq_file *m, void *v)
64 {
65 int index = 0;
66
67 seq_printf(m, "processor\t: %d\n", index);
68 seq_printf(m, "vendor_id\t: User Mode Linux\n");
69 seq_printf(m, "model name\t: UML\n");
70 seq_printf(m, "mode\t\t: skas\n");
71 seq_printf(m, "host\t\t: %s\n", host_info);
72 seq_printf(m, "bogomips\t: %lu.%02lu\n\n",
73 loops_per_jiffy/(500000/HZ),
74 (loops_per_jiffy/(5000/HZ)) % 100);
75
76 return 0;
77 }
78
c_start(struct seq_file * m,loff_t * pos)79 static void *c_start(struct seq_file *m, loff_t *pos)
80 {
81 return *pos < nr_cpu_ids ? cpu_data + *pos : NULL;
82 }
83
c_next(struct seq_file * m,void * v,loff_t * pos)84 static void *c_next(struct seq_file *m, void *v, loff_t *pos)
85 {
86 ++*pos;
87 return c_start(m, pos);
88 }
89
c_stop(struct seq_file * m,void * v)90 static void c_stop(struct seq_file *m, void *v)
91 {
92 }
93
94 const struct seq_operations cpuinfo_op = {
95 .start = c_start,
96 .next = c_next,
97 .stop = c_stop,
98 .show = show_cpuinfo,
99 };
100
101 /* Set in linux_main */
102 unsigned long uml_physmem;
103 EXPORT_SYMBOL(uml_physmem);
104
105 unsigned long uml_reserved; /* Also modified in mem_init */
106 unsigned long start_vm;
107 unsigned long end_vm;
108
109 /* Set in uml_ncpus_setup */
110 int ncpus = 1;
111
112 /* Set in early boot */
113 static int have_root __initdata = 0;
114
115 /* Set in uml_mem_setup and modified in linux_main */
116 long long physmem_size = 32 * 1024 * 1024;
117 EXPORT_SYMBOL(physmem_size);
118
119 static const char *usage_string =
120 "User Mode Linux v%s\n"
121 " available at http://user-mode-linux.sourceforge.net/\n\n";
122
uml_version_setup(char * line,int * add)123 static int __init uml_version_setup(char *line, int *add)
124 {
125 /* Explicitly use printf() to show version in stdout */
126 printf("%s\n", init_utsname()->release);
127 exit(0);
128
129 return 0;
130 }
131
132 __uml_setup("--version", uml_version_setup,
133 "--version\n"
134 " Prints the version number of the kernel.\n\n"
135 );
136
uml_root_setup(char * line,int * add)137 static int __init uml_root_setup(char *line, int *add)
138 {
139 have_root = 1;
140 return 0;
141 }
142
143 __uml_setup("root=", uml_root_setup,
144 "root=<file containing the root fs>\n"
145 " This is actually used by the generic kernel in exactly the same\n"
146 " way as in any other kernel. If you configure a number of block\n"
147 " devices and want to boot off something other than ubd0, you \n"
148 " would use something like:\n"
149 " root=/dev/ubd5\n\n"
150 );
151
no_skas_debug_setup(char * line,int * add)152 static int __init no_skas_debug_setup(char *line, int *add)
153 {
154 os_warn("'debug' is not necessary to gdb UML in skas mode - run\n");
155 os_warn("'gdb linux'\n");
156
157 return 0;
158 }
159
160 __uml_setup("debug", no_skas_debug_setup,
161 "debug\n"
162 " this flag is not needed to run gdb on UML in skas mode\n\n"
163 );
164
Usage(char * line,int * add)165 static int __init Usage(char *line, int *add)
166 {
167 const char **p;
168
169 printf(usage_string, init_utsname()->release);
170 p = &__uml_help_start;
171 /* Explicitly use printf() to show help in stdout */
172 while (p < &__uml_help_end) {
173 printf("%s", *p);
174 p++;
175 }
176 exit(0);
177 return 0;
178 }
179
180 __uml_setup("--help", Usage,
181 "--help\n"
182 " Prints this message.\n\n"
183 );
184
uml_checksetup(char * line,int * add)185 static void __init uml_checksetup(char *line, int *add)
186 {
187 struct uml_param *p;
188
189 p = &__uml_setup_start;
190 while (p < &__uml_setup_end) {
191 size_t n;
192
193 n = strlen(p->str);
194 if (!strncmp(line, p->str, n) && p->setup_func(line + n, add))
195 return;
196 p++;
197 }
198 }
199
uml_postsetup(void)200 static void __init uml_postsetup(void)
201 {
202 initcall_t *p;
203
204 p = &__uml_postsetup_start;
205 while (p < &__uml_postsetup_end) {
206 (*p)();
207 p++;
208 }
209 return;
210 }
211
panic_exit(struct notifier_block * self,unsigned long unused1,void * unused2)212 static int panic_exit(struct notifier_block *self, unsigned long unused1,
213 void *unused2)
214 {
215 kmsg_dump(KMSG_DUMP_PANIC);
216 bust_spinlocks(1);
217 bust_spinlocks(0);
218 uml_exitcode = 1;
219 os_dump_core();
220 return 0;
221 }
222
223 static struct notifier_block panic_exit_notifier = {
224 .notifier_call = panic_exit,
225 .next = NULL,
226 .priority = 0
227 };
228
uml_finishsetup(void)229 void uml_finishsetup(void)
230 {
231 atomic_notifier_chain_register(&panic_notifier_list,
232 &panic_exit_notifier);
233
234 uml_postsetup();
235
236 new_thread_handler();
237 }
238
239 /* Set during early boot */
240 unsigned long task_size;
241 EXPORT_SYMBOL(task_size);
242
243 unsigned long host_task_size;
244
245 unsigned long brk_start;
246 unsigned long end_iomem;
247 EXPORT_SYMBOL(end_iomem);
248
249 #define MIN_VMALLOC (32 * 1024 * 1024)
250
linux_main(int argc,char ** argv)251 int __init linux_main(int argc, char **argv)
252 {
253 unsigned long avail, diff;
254 unsigned long virtmem_size, max_physmem;
255 unsigned long stack;
256 unsigned int i;
257 int add;
258
259 for (i = 1; i < argc; i++) {
260 if ((i == 1) && (argv[i][0] == ' '))
261 continue;
262 add = 1;
263 uml_checksetup(argv[i], &add);
264 if (add)
265 add_arg(argv[i]);
266 }
267 if (have_root == 0)
268 add_arg(DEFAULT_COMMAND_LINE);
269
270 host_task_size = os_get_top_address();
271 /*
272 * TASK_SIZE needs to be PGDIR_SIZE aligned or else exit_mmap craps
273 * out
274 */
275 task_size = host_task_size & PGDIR_MASK;
276
277 /* OS sanity checks that need to happen before the kernel runs */
278 os_early_checks();
279
280 brk_start = (unsigned long) sbrk(0);
281
282 /*
283 * Increase physical memory size for exec-shield users
284 * so they actually get what they asked for. This should
285 * add zero for non-exec shield users
286 */
287
288 diff = UML_ROUND_UP(brk_start) - UML_ROUND_UP(&_end);
289 if (diff > 1024 * 1024) {
290 os_info("Adding %ld bytes to physical memory to account for "
291 "exec-shield gap\n", diff);
292 physmem_size += UML_ROUND_UP(brk_start) - UML_ROUND_UP(&_end);
293 }
294
295 uml_physmem = (unsigned long) __binary_start & PAGE_MASK;
296
297 /* Reserve up to 4M after the current brk */
298 uml_reserved = ROUND_4M(brk_start) + (1 << 22);
299
300 setup_machinename(init_utsname()->machine);
301
302 highmem = 0;
303 iomem_size = (iomem_size + PAGE_SIZE - 1) & PAGE_MASK;
304 max_physmem = TASK_SIZE - uml_physmem - iomem_size - MIN_VMALLOC;
305
306 /*
307 * Zones have to begin on a 1 << MAX_ORDER page boundary,
308 * so this makes sure that's true for highmem
309 */
310 max_physmem &= ~((1 << (PAGE_SHIFT + MAX_ORDER)) - 1);
311 if (physmem_size + iomem_size > max_physmem) {
312 highmem = physmem_size + iomem_size - max_physmem;
313 physmem_size -= highmem;
314 }
315
316 high_physmem = uml_physmem + physmem_size;
317 end_iomem = high_physmem + iomem_size;
318 high_memory = (void *) end_iomem;
319
320 start_vm = VMALLOC_START;
321
322 virtmem_size = physmem_size;
323 stack = (unsigned long) argv;
324 stack &= ~(1024 * 1024 - 1);
325 avail = stack - start_vm;
326 if (physmem_size > avail)
327 virtmem_size = avail;
328 end_vm = start_vm + virtmem_size;
329
330 if (virtmem_size < physmem_size)
331 os_info("Kernel virtual memory size shrunk to %lu bytes\n",
332 virtmem_size);
333
334 os_flush_stdout();
335
336 return start_uml();
337 }
338
read_initrd(void)339 int __init __weak read_initrd(void)
340 {
341 return 0;
342 }
343
setup_arch(char ** cmdline_p)344 void __init setup_arch(char **cmdline_p)
345 {
346 stack_protections((unsigned long) &init_thread_info);
347 setup_physmem(uml_physmem, uml_reserved, physmem_size, highmem);
348 mem_total_pages(physmem_size, iomem_size, highmem);
349 read_initrd();
350
351 paging_init();
352 strlcpy(boot_command_line, command_line, COMMAND_LINE_SIZE);
353 *cmdline_p = command_line;
354 setup_hostinfo(host_info, sizeof host_info);
355 }
356
arch_cpu_finalize_init(void)357 void __init arch_cpu_finalize_init(void)
358 {
359 arch_check_bugs();
360 os_check_bugs();
361 }
362
apply_retpolines(s32 * start,s32 * end)363 void apply_retpolines(s32 *start, s32 *end)
364 {
365 }
366
apply_returns(s32 * start,s32 * end)367 void apply_returns(s32 *start, s32 *end)
368 {
369 }
370
apply_alternatives(struct alt_instr * start,struct alt_instr * end)371 void apply_alternatives(struct alt_instr *start, struct alt_instr *end)
372 {
373 }
374
text_poke(void * addr,const void * opcode,size_t len)375 void *text_poke(void *addr, const void *opcode, size_t len)
376 {
377 /*
378 * In UML, the only reference to this function is in
379 * apply_relocate_add(), which shouldn't ever actually call this
380 * because UML doesn't have live patching.
381 */
382 WARN_ON(1);
383
384 return memcpy(addr, opcode, len);
385 }
386
text_poke_sync(void)387 void text_poke_sync(void)
388 {
389 }
390
uml_pm_wake(void)391 void uml_pm_wake(void)
392 {
393 pm_system_wakeup();
394 }
395
396 #ifdef CONFIG_PM_SLEEP
init_pm_wake_signal(void)397 static int init_pm_wake_signal(void)
398 {
399 /*
400 * In external time-travel mode we can't use signals to wake up
401 * since that would mess with the scheduling. We'll have to do
402 * some additional work to support wakeup on virtio devices or
403 * similar, perhaps implementing a fake RTC controller that can
404 * trigger wakeup (and request the appropriate scheduling from
405 * the external scheduler when going to suspend.)
406 */
407 if (time_travel_mode != TT_MODE_EXTERNAL)
408 register_pm_wake_signal();
409 return 0;
410 }
411
412 late_initcall(init_pm_wake_signal);
413 #endif
414