xref: /linux/arch/um/kernel/um_arch.c (revision 42fda66387daa53538ae13a2c858396aaf037158)
1 /*
2  * Copyright (C) 2000, 2002 Jeff Dike (jdike@karaya.com)
3  * Licensed under the GPL
4  */
5 
6 #include "linux/kernel.h"
7 #include "linux/sched.h"
8 #include "linux/notifier.h"
9 #include "linux/mm.h"
10 #include "linux/types.h"
11 #include "linux/tty.h"
12 #include "linux/init.h"
13 #include "linux/bootmem.h"
14 #include "linux/spinlock.h"
15 #include "linux/utsname.h"
16 #include "linux/sysrq.h"
17 #include "linux/seq_file.h"
18 #include "linux/delay.h"
19 #include "linux/module.h"
20 #include "linux/utsname.h"
21 #include "asm/page.h"
22 #include "asm/pgtable.h"
23 #include "asm/ptrace.h"
24 #include "asm/elf.h"
25 #include "asm/user.h"
26 #include "asm/setup.h"
27 #include "ubd_user.h"
28 #include "asm/current.h"
29 #include "kern_util.h"
30 #include "as-layout.h"
31 #include "arch.h"
32 #include "kern.h"
33 #include "mem_user.h"
34 #include "mem.h"
35 #include "initrd.h"
36 #include "init.h"
37 #include "os.h"
38 #include "choose-mode.h"
39 #include "mode_kern.h"
40 #include "mode.h"
41 #include "skas.h"
42 
43 #define DEFAULT_COMMAND_LINE "root=98:0"
44 
45 /* Changed in add_arg and setup_arch, which run before SMP is started */
46 static char __initdata command_line[COMMAND_LINE_SIZE] = { 0 };
47 
48 static void __init add_arg(char *arg)
49 {
50 	if (strlen(command_line) + strlen(arg) + 1 > COMMAND_LINE_SIZE) {
51 		printf("add_arg: Too many command line arguments!\n");
52 		exit(1);
53 	}
54 	if(strlen(command_line) > 0)
55 		strcat(command_line, " ");
56 	strcat(command_line, arg);
57 }
58 
59 /*
60  * These fields are initialized at boot time and not changed.
61  * XXX This structure is used only in the non-SMP case.  Maybe this
62  * should be moved to smp.c.
63  */
64 struct cpuinfo_um boot_cpu_data = {
65 	.loops_per_jiffy	= 0,
66 	.ipi_pipe		= { -1, -1 }
67 };
68 
69 unsigned long thread_saved_pc(struct task_struct *task)
70 {
71 	return os_process_pc(CHOOSE_MODE_PROC(thread_pid_tt, thread_pid_skas,
72 					      task));
73 }
74 
75 /* Changed in setup_arch, which is called in early boot */
76 static char host_info[(__NEW_UTS_LEN + 1) * 5];
77 
78 static int show_cpuinfo(struct seq_file *m, void *v)
79 {
80 	int index = 0;
81 
82 #ifdef CONFIG_SMP
83 	index = (struct cpuinfo_um *) v - cpu_data;
84 	if (!cpu_online(index))
85 		return 0;
86 #endif
87 
88 	seq_printf(m, "processor\t: %d\n", index);
89 	seq_printf(m, "vendor_id\t: User Mode Linux\n");
90 	seq_printf(m, "model name\t: UML\n");
91 	seq_printf(m, "mode\t\t: %s\n", CHOOSE_MODE("tt", "skas"));
92 	seq_printf(m, "host\t\t: %s\n", host_info);
93 	seq_printf(m, "bogomips\t: %lu.%02lu\n\n",
94 		   loops_per_jiffy/(500000/HZ),
95 		   (loops_per_jiffy/(5000/HZ)) % 100);
96 
97 	return 0;
98 }
99 
100 static void *c_start(struct seq_file *m, loff_t *pos)
101 {
102 	return *pos < NR_CPUS ? cpu_data + *pos : NULL;
103 }
104 
105 static void *c_next(struct seq_file *m, void *v, loff_t *pos)
106 {
107 	++*pos;
108 	return c_start(m, pos);
109 }
110 
111 static void c_stop(struct seq_file *m, void *v)
112 {
113 }
114 
115 const struct seq_operations cpuinfo_op = {
116 	.start	= c_start,
117 	.next	= c_next,
118 	.stop	= c_stop,
119 	.show	= show_cpuinfo,
120 };
121 
122 /* Set in linux_main */
123 unsigned long host_task_size;
124 unsigned long task_size;
125 unsigned long uml_physmem;
126 unsigned long uml_reserved; /* Also modified in mem_init */
127 unsigned long start_vm;
128 unsigned long end_vm;
129 
130 /* Set in uml_ncpus_setup */
131 int ncpus = 1;
132 
133 /* Set in early boot */
134 static int have_root __initdata = 0;
135 
136 /* Set in uml_mem_setup and modified in linux_main */
137 long long physmem_size = 32 * 1024 * 1024;
138 
139 static char *usage_string =
140 "User Mode Linux v%s\n"
141 "	available at http://user-mode-linux.sourceforge.net/\n\n";
142 
143 static int __init uml_version_setup(char *line, int *add)
144 {
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 
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 
171 static int __init no_skas_debug_setup(char *line, int *add)
172 {
173 	printf("'debug' is not necessary to gdb UML in skas mode - run \n");
174 	printf("'gdb linux'");
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 
184 #ifdef CONFIG_SMP
185 static int __init uml_ncpus_setup(char *line, int *add)
186 {
187 	if (!sscanf(line, "%d", &ncpus)) {
188 		printf("Couldn't parse [%s]\n", line);
189 		return -1;
190 	}
191 
192 	return 0;
193 }
194 
195 __uml_setup("ncpus=", uml_ncpus_setup,
196 "ncpus=<# of desired CPUs>\n"
197 "    This tells an SMP kernel how many virtual processors to start.\n\n"
198 );
199 #endif
200 
201 static int __init Usage(char *line, int *add)
202 {
203 	const char **p;
204 
205 	printf(usage_string, init_utsname()->release);
206 	p = &__uml_help_start;
207 	while (p < &__uml_help_end) {
208 		printf("%s", *p);
209 		p++;
210 	}
211 	exit(0);
212 	return 0;
213 }
214 
215 __uml_setup("--help", Usage,
216 "--help\n"
217 "    Prints this message.\n\n"
218 );
219 
220 static int __init uml_checksetup(char *line, int *add)
221 {
222 	struct uml_param *p;
223 
224 	p = &__uml_setup_start;
225 	while(p < &__uml_setup_end) {
226 		int n;
227 
228 		n = strlen(p->str);
229 		if(!strncmp(line, p->str, n)){
230 			if (p->setup_func(line + n, add)) return 1;
231 		}
232 		p++;
233 	}
234 	return 0;
235 }
236 
237 static void __init uml_postsetup(void)
238 {
239 	initcall_t *p;
240 
241 	p = &__uml_postsetup_start;
242 	while(p < &__uml_postsetup_end){
243 		(*p)();
244 		p++;
245 	}
246 	return;
247 }
248 
249 /* Set during early boot */
250 unsigned long brk_start;
251 unsigned long end_iomem;
252 EXPORT_SYMBOL(end_iomem);
253 
254 #define MIN_VMALLOC (32 * 1024 * 1024)
255 
256 extern char __binary_start;
257 
258 int __init linux_main(int argc, char **argv)
259 {
260 	unsigned long avail, diff;
261 	unsigned long virtmem_size, max_physmem;
262 	unsigned int i, add;
263 	char * mode;
264 
265 	for (i = 1; i < argc; i++){
266 		if((i == 1) && (argv[i][0] == ' ')) continue;
267 		add = 1;
268 		uml_checksetup(argv[i], &add);
269 		if (add)
270 			add_arg(argv[i]);
271 	}
272 	if(have_root == 0)
273 		add_arg(DEFAULT_COMMAND_LINE);
274 
275 	os_early_checks();
276 
277 	can_do_skas();
278 
279 	if (proc_mm && ptrace_faultinfo)
280 		mode = "SKAS3";
281 	else
282 		mode = "SKAS0";
283 
284 	printf("UML running in %s mode\n", mode);
285 
286 	host_task_size = CHOOSE_MODE_PROC(set_task_sizes_tt,
287 					  set_task_sizes_skas, &task_size);
288 
289 	/*
290 	 * Setting up handlers to 'sig_info' struct
291 	 */
292 	os_fill_handlinfo(handlinfo_kern);
293 
294 	brk_start = (unsigned long) sbrk(0);
295 	CHOOSE_MODE_PROC(before_mem_tt, before_mem_skas, brk_start);
296 	/* Increase physical memory size for exec-shield users
297 	so they actually get what they asked for. This should
298 	add zero for non-exec shield users */
299 
300 	diff = UML_ROUND_UP(brk_start) - UML_ROUND_UP(&_end);
301 	if(diff > 1024 * 1024){
302 		printf("Adding %ld bytes to physical memory to account for "
303 		       "exec-shield gap\n", diff);
304 		physmem_size += UML_ROUND_UP(brk_start) - UML_ROUND_UP(&_end);
305 	}
306 
307 	uml_physmem = (unsigned long) &__binary_start & PAGE_MASK;
308 
309 	/* Reserve up to 4M after the current brk */
310 	uml_reserved = ROUND_4M(brk_start) + (1 << 22);
311 
312 	setup_machinename(init_utsname()->machine);
313 
314 	highmem = 0;
315 	iomem_size = (iomem_size + PAGE_SIZE - 1) & PAGE_MASK;
316 	max_physmem = get_kmem_end() - uml_physmem - iomem_size - MIN_VMALLOC;
317 
318 	/* Zones have to begin on a 1 << MAX_ORDER page boundary,
319 	 * so this makes sure that's true for highmem
320 	 */
321 	max_physmem &= ~((1 << (PAGE_SHIFT + MAX_ORDER)) - 1);
322 	if(physmem_size + iomem_size > max_physmem){
323 		highmem = physmem_size + iomem_size - max_physmem;
324 		physmem_size -= highmem;
325 #ifndef CONFIG_HIGHMEM
326 		highmem = 0;
327 		printf("CONFIG_HIGHMEM not enabled - physical memory shrunk "
328 		       "to %Lu bytes\n", physmem_size);
329 #endif
330 	}
331 
332 	high_physmem = uml_physmem + physmem_size;
333 	end_iomem = high_physmem + iomem_size;
334 	high_memory = (void *) end_iomem;
335 
336 	start_vm = VMALLOC_START;
337 
338 	setup_physmem(uml_physmem, uml_reserved, physmem_size, highmem);
339 	if(init_maps(physmem_size, iomem_size, highmem)){
340 		printf("Failed to allocate mem_map for %Lu bytes of physical "
341 		       "memory and %Lu bytes of highmem\n", physmem_size,
342 		       highmem);
343 		exit(1);
344 	}
345 
346 	virtmem_size = physmem_size;
347 	avail = get_kmem_end() - start_vm;
348 	if(physmem_size > avail) virtmem_size = avail;
349 	end_vm = start_vm + virtmem_size;
350 
351 	if(virtmem_size < physmem_size)
352 		printf("Kernel virtual memory size shrunk to %lu bytes\n",
353 		       virtmem_size);
354 
355 	uml_postsetup();
356 
357 	stack_protections((unsigned long) &init_thread_info);
358 	os_flush_stdout();
359 
360 	return CHOOSE_MODE(start_uml_tt(), start_uml_skas());
361 }
362 
363 extern int uml_exitcode;
364 
365 static int panic_exit(struct notifier_block *self, unsigned long unused1,
366 		      void *unused2)
367 {
368 	bust_spinlocks(1);
369 	show_regs(&(current->thread.regs));
370 	bust_spinlocks(0);
371 	uml_exitcode = 1;
372 	os_dump_core();
373 	return 0;
374 }
375 
376 static struct notifier_block panic_exit_notifier = {
377 	.notifier_call 		= panic_exit,
378 	.next 			= NULL,
379 	.priority 		= 0
380 };
381 
382 void __init setup_arch(char **cmdline_p)
383 {
384 	atomic_notifier_chain_register(&panic_notifier_list,
385 			&panic_exit_notifier);
386 	paging_init();
387 	strlcpy(boot_command_line, command_line, COMMAND_LINE_SIZE);
388 	*cmdline_p = command_line;
389 	setup_hostinfo(host_info, sizeof host_info);
390 }
391 
392 void __init check_bugs(void)
393 {
394 	arch_check_bugs();
395 	os_check_bugs();
396 }
397 
398 void apply_alternatives(struct alt_instr *start, struct alt_instr *end)
399 {
400 }
401 
402 #ifdef CONFIG_SMP
403 void alternatives_smp_module_add(struct module *mod, char *name,
404 				 void *locks, void *locks_end,
405 				 void *text,  void *text_end)
406 {
407 }
408 
409 void alternatives_smp_module_del(struct module *mod)
410 {
411 }
412 #endif
413