xref: /linux/arch/um/kernel/um_arch.c (revision 2a2c74b2efcb1a0ca3fdcb5fbb96ad8de6a29177)
1 /*
2  * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
3  * Licensed under the GPL
4  */
5 
6 #include <linux/delay.h>
7 #include <linux/init.h>
8 #include <linux/mm.h>
9 #include <linux/module.h>
10 #include <linux/seq_file.h>
11 #include <linux/string.h>
12 #include <linux/utsname.h>
13 #include <linux/sched.h>
14 #include <asm/pgtable.h>
15 #include <asm/processor.h>
16 #include <asm/sections.h>
17 #include <asm/setup.h>
18 #include <as-layout.h>
19 #include <arch.h>
20 #include <init.h>
21 #include <kern.h>
22 #include <kern_util.h>
23 #include <mem_user.h>
24 #include <os.h>
25 
26 #define DEFAULT_COMMAND_LINE "root=98:0"
27 
28 /* Changed in add_arg and setup_arch, which run before SMP is started */
29 static char __initdata command_line[COMMAND_LINE_SIZE] = { 0 };
30 
31 static void __init add_arg(char *arg)
32 {
33 	if (strlen(command_line) + strlen(arg) + 1 > COMMAND_LINE_SIZE) {
34 		printf("add_arg: Too many command line arguments!\n");
35 		exit(1);
36 	}
37 	if (strlen(command_line) > 0)
38 		strcat(command_line, " ");
39 	strcat(command_line, arg);
40 }
41 
42 /*
43  * These fields are initialized at boot time and not changed.
44  * XXX This structure is used only in the non-SMP case.  Maybe this
45  * should be moved to smp.c.
46  */
47 struct cpuinfo_um boot_cpu_data = {
48 	.loops_per_jiffy	= 0,
49 	.ipi_pipe		= { -1, -1 }
50 };
51 
52 union thread_union cpu0_irqstack
53 	__attribute__((__section__(".data..init_irqstack"))) =
54 		{ INIT_THREAD_INFO(init_task) };
55 
56 unsigned long thread_saved_pc(struct task_struct *task)
57 {
58 	/* FIXME: Need to look up userspace_pid by cpu */
59 	return os_process_pc(userspace_pid[0]);
60 }
61 
62 /* Changed in setup_arch, which is called in early boot */
63 static char host_info[(__NEW_UTS_LEN + 1) * 5];
64 
65 static int show_cpuinfo(struct seq_file *m, void *v)
66 {
67 	int index = 0;
68 
69 #ifdef CONFIG_SMP
70 	index = (struct cpuinfo_um *) v - cpu_data;
71 	if (!cpu_online(index))
72 		return 0;
73 #endif
74 
75 	seq_printf(m, "processor\t: %d\n", index);
76 	seq_printf(m, "vendor_id\t: User Mode Linux\n");
77 	seq_printf(m, "model name\t: UML\n");
78 	seq_printf(m, "mode\t\t: skas\n");
79 	seq_printf(m, "host\t\t: %s\n", host_info);
80 	seq_printf(m, "bogomips\t: %lu.%02lu\n\n",
81 		   loops_per_jiffy/(500000/HZ),
82 		   (loops_per_jiffy/(5000/HZ)) % 100);
83 
84 	return 0;
85 }
86 
87 static void *c_start(struct seq_file *m, loff_t *pos)
88 {
89 	return *pos < NR_CPUS ? cpu_data + *pos : NULL;
90 }
91 
92 static void *c_next(struct seq_file *m, void *v, loff_t *pos)
93 {
94 	++*pos;
95 	return c_start(m, pos);
96 }
97 
98 static void c_stop(struct seq_file *m, void *v)
99 {
100 }
101 
102 const struct seq_operations cpuinfo_op = {
103 	.start	= c_start,
104 	.next	= c_next,
105 	.stop	= c_stop,
106 	.show	= show_cpuinfo,
107 };
108 
109 /* Set in linux_main */
110 unsigned long uml_physmem;
111 EXPORT_SYMBOL(uml_physmem);
112 
113 unsigned long uml_reserved; /* Also modified in mem_init */
114 unsigned long start_vm;
115 unsigned long end_vm;
116 
117 /* Set in uml_ncpus_setup */
118 int ncpus = 1;
119 
120 /* Set in early boot */
121 static int have_root __initdata = 0;
122 
123 /* Set in uml_mem_setup and modified in linux_main */
124 long long physmem_size = 32 * 1024 * 1024;
125 
126 static const char *usage_string =
127 "User Mode Linux v%s\n"
128 "	available at http://user-mode-linux.sourceforge.net/\n\n";
129 
130 static int __init uml_version_setup(char *line, int *add)
131 {
132 	printf("%s\n", init_utsname()->release);
133 	exit(0);
134 
135 	return 0;
136 }
137 
138 __uml_setup("--version", uml_version_setup,
139 "--version\n"
140 "    Prints the version number of the kernel.\n\n"
141 );
142 
143 static int __init uml_root_setup(char *line, int *add)
144 {
145 	have_root = 1;
146 	return 0;
147 }
148 
149 __uml_setup("root=", uml_root_setup,
150 "root=<file containing the root fs>\n"
151 "    This is actually used by the generic kernel in exactly the same\n"
152 "    way as in any other kernel. If you configure a number of block\n"
153 "    devices and want to boot off something other than ubd0, you \n"
154 "    would use something like:\n"
155 "        root=/dev/ubd5\n\n"
156 );
157 
158 static int __init no_skas_debug_setup(char *line, int *add)
159 {
160 	printf("'debug' is not necessary to gdb UML in skas mode - run \n");
161 	printf("'gdb linux'\n");
162 
163 	return 0;
164 }
165 
166 __uml_setup("debug", no_skas_debug_setup,
167 "debug\n"
168 "    this flag is not needed to run gdb on UML in skas mode\n\n"
169 );
170 
171 #ifdef CONFIG_SMP
172 static int __init uml_ncpus_setup(char *line, int *add)
173 {
174 	if (!sscanf(line, "%d", &ncpus)) {
175 		printf("Couldn't parse [%s]\n", line);
176 		return -1;
177 	}
178 
179 	return 0;
180 }
181 
182 __uml_setup("ncpus=", uml_ncpus_setup,
183 "ncpus=<# of desired CPUs>\n"
184 "    This tells an SMP kernel how many virtual processors to start.\n\n"
185 );
186 #endif
187 
188 static int __init Usage(char *line, int *add)
189 {
190 	const char **p;
191 
192 	printf(usage_string, init_utsname()->release);
193 	p = &__uml_help_start;
194 	while (p < &__uml_help_end) {
195 		printf("%s", *p);
196 		p++;
197 	}
198 	exit(0);
199 	return 0;
200 }
201 
202 __uml_setup("--help", Usage,
203 "--help\n"
204 "    Prints this message.\n\n"
205 );
206 
207 static void __init uml_checksetup(char *line, int *add)
208 {
209 	struct uml_param *p;
210 
211 	p = &__uml_setup_start;
212 	while (p < &__uml_setup_end) {
213 		size_t n;
214 
215 		n = strlen(p->str);
216 		if (!strncmp(line, p->str, n) && p->setup_func(line + n, add))
217 			return;
218 		p++;
219 	}
220 }
221 
222 static void __init uml_postsetup(void)
223 {
224 	initcall_t *p;
225 
226 	p = &__uml_postsetup_start;
227 	while (p < &__uml_postsetup_end) {
228 		(*p)();
229 		p++;
230 	}
231 	return;
232 }
233 
234 static int panic_exit(struct notifier_block *self, unsigned long unused1,
235 		      void *unused2)
236 {
237 	bust_spinlocks(1);
238 	bust_spinlocks(0);
239 	uml_exitcode = 1;
240 	os_dump_core();
241 	return 0;
242 }
243 
244 static struct notifier_block panic_exit_notifier = {
245 	.notifier_call 		= panic_exit,
246 	.next 			= NULL,
247 	.priority 		= 0
248 };
249 
250 /* Set during early boot */
251 unsigned long task_size;
252 EXPORT_SYMBOL(task_size);
253 
254 unsigned long host_task_size;
255 
256 unsigned long brk_start;
257 unsigned long end_iomem;
258 EXPORT_SYMBOL(end_iomem);
259 
260 #define MIN_VMALLOC (32 * 1024 * 1024)
261 
262 extern char __binary_start;
263 
264 int __init linux_main(int argc, char **argv)
265 {
266 	unsigned long avail, diff;
267 	unsigned long virtmem_size, max_physmem;
268 	unsigned long stack;
269 	unsigned int i;
270 	int add;
271 	char * mode;
272 
273 	for (i = 1; i < argc; i++) {
274 		if ((i == 1) && (argv[i][0] == ' '))
275 			continue;
276 		add = 1;
277 		uml_checksetup(argv[i], &add);
278 		if (add)
279 			add_arg(argv[i]);
280 	}
281 	if (have_root == 0)
282 		add_arg(DEFAULT_COMMAND_LINE);
283 
284 	host_task_size = os_get_top_address();
285 	/*
286 	 * TASK_SIZE needs to be PGDIR_SIZE aligned or else exit_mmap craps
287 	 * out
288 	 */
289 	task_size = host_task_size & PGDIR_MASK;
290 
291 	/* OS sanity checks that need to happen before the kernel runs */
292 	os_early_checks();
293 
294 	can_do_skas();
295 
296 	if (proc_mm && ptrace_faultinfo)
297 		mode = "SKAS3";
298 	else
299 		mode = "SKAS0";
300 
301 	printf("UML running in %s mode\n", mode);
302 
303 	brk_start = (unsigned long) sbrk(0);
304 
305 	/*
306 	 * Increase physical memory size for exec-shield users
307 	 * so they actually get what they asked for. This should
308 	 * add zero for non-exec shield users
309 	 */
310 
311 	diff = UML_ROUND_UP(brk_start) - UML_ROUND_UP(&_end);
312 	if (diff > 1024 * 1024) {
313 		printf("Adding %ld bytes to physical memory to account for "
314 		       "exec-shield gap\n", diff);
315 		physmem_size += UML_ROUND_UP(brk_start) - UML_ROUND_UP(&_end);
316 	}
317 
318 	uml_physmem = (unsigned long) &__binary_start & PAGE_MASK;
319 
320 	/* Reserve up to 4M after the current brk */
321 	uml_reserved = ROUND_4M(brk_start) + (1 << 22);
322 
323 	setup_machinename(init_utsname()->machine);
324 
325 	highmem = 0;
326 	iomem_size = (iomem_size + PAGE_SIZE - 1) & PAGE_MASK;
327 	max_physmem = TASK_SIZE - uml_physmem - iomem_size - MIN_VMALLOC;
328 
329 	/*
330 	 * Zones have to begin on a 1 << MAX_ORDER page boundary,
331 	 * so this makes sure that's true for highmem
332 	 */
333 	max_physmem &= ~((1 << (PAGE_SHIFT + MAX_ORDER)) - 1);
334 	if (physmem_size + iomem_size > max_physmem) {
335 		highmem = physmem_size + iomem_size - max_physmem;
336 		physmem_size -= highmem;
337 #ifndef CONFIG_HIGHMEM
338 		highmem = 0;
339 		printf("CONFIG_HIGHMEM not enabled - physical memory shrunk "
340 		       "to %Lu bytes\n", physmem_size);
341 #endif
342 	}
343 
344 	high_physmem = uml_physmem + physmem_size;
345 	end_iomem = high_physmem + iomem_size;
346 	high_memory = (void *) end_iomem;
347 
348 	start_vm = VMALLOC_START;
349 
350 	setup_physmem(uml_physmem, uml_reserved, physmem_size, highmem);
351 	if (init_maps(physmem_size, iomem_size, highmem)) {
352 		printf("Failed to allocate mem_map for %Lu bytes of physical "
353 		       "memory and %Lu bytes of highmem\n", physmem_size,
354 		       highmem);
355 		exit(1);
356 	}
357 
358 	virtmem_size = physmem_size;
359 	stack = (unsigned long) argv;
360 	stack &= ~(1024 * 1024 - 1);
361 	avail = stack - start_vm;
362 	if (physmem_size > avail)
363 		virtmem_size = avail;
364 	end_vm = start_vm + virtmem_size;
365 
366 	if (virtmem_size < physmem_size)
367 		printf("Kernel virtual memory size shrunk to %lu bytes\n",
368 		       virtmem_size);
369 
370 	atomic_notifier_chain_register(&panic_notifier_list,
371 				       &panic_exit_notifier);
372 
373 	uml_postsetup();
374 
375 	stack_protections((unsigned long) &init_thread_info);
376 	os_flush_stdout();
377 
378 	return start_uml();
379 }
380 
381 void __init setup_arch(char **cmdline_p)
382 {
383 	paging_init();
384 	strlcpy(boot_command_line, command_line, COMMAND_LINE_SIZE);
385 	*cmdline_p = command_line;
386 	setup_hostinfo(host_info, sizeof host_info);
387 }
388 
389 void __init check_bugs(void)
390 {
391 	arch_check_bugs();
392 	os_check_bugs();
393 }
394 
395 void apply_alternatives(struct alt_instr *start, struct alt_instr *end)
396 {
397 }
398 
399 #ifdef CONFIG_SMP
400 void alternatives_smp_module_add(struct module *mod, char *name,
401 				 void *locks, void *locks_end,
402 				 void *text,  void *text_end)
403 {
404 }
405 
406 void alternatives_smp_module_del(struct module *mod)
407 {
408 }
409 #endif
410