xref: /openbmc/linux/arch/um/kernel/um_arch.c (revision 96de0e252cedffad61b3cb5e05662c591898e69a)
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/mm.h"
8 #include "linux/module.h"
9 #include "linux/seq_file.h"
10 #include "linux/string.h"
11 #include "linux/utsname.h"
12 #include "asm/pgtable.h"
13 #include "asm/processor.h"
14 #include "asm/setup.h"
15 #include "arch.h"
16 #include "as-layout.h"
17 #include "init.h"
18 #include "kern.h"
19 #include "mem_user.h"
20 #include "os.h"
21 #include "skas.h"
22 
23 #define DEFAULT_COMMAND_LINE "root=98:0"
24 
25 /* Changed in add_arg and setup_arch, which run before SMP is started */
26 static char __initdata command_line[COMMAND_LINE_SIZE] = { 0 };
27 
28 static void __init add_arg(char *arg)
29 {
30 	if (strlen(command_line) + strlen(arg) + 1 > COMMAND_LINE_SIZE) {
31 		printf("add_arg: Too many command line arguments!\n");
32 		exit(1);
33 	}
34 	if (strlen(command_line) > 0)
35 		strcat(command_line, " ");
36 	strcat(command_line, arg);
37 }
38 
39 /*
40  * These fields are initialized at boot time and not changed.
41  * XXX This structure is used only in the non-SMP case.  Maybe this
42  * should be moved to smp.c.
43  */
44 struct cpuinfo_um boot_cpu_data = {
45 	.loops_per_jiffy	= 0,
46 	.ipi_pipe		= { -1, -1 }
47 };
48 
49 unsigned long thread_saved_pc(struct task_struct *task)
50 {
51 	/* FIXME: Need to look up userspace_pid by cpu */
52 	return os_process_pc(userspace_pid[0]);
53 }
54 
55 /* Changed in setup_arch, which is called in early boot */
56 static char host_info[(__NEW_UTS_LEN + 1) * 5];
57 
58 static int show_cpuinfo(struct seq_file *m, void *v)
59 {
60 	int index = 0;
61 
62 #ifdef CONFIG_SMP
63 	index = (struct cpuinfo_um *) v - cpu_data;
64 	if (!cpu_online(index))
65 		return 0;
66 #endif
67 
68 	seq_printf(m, "processor\t: %d\n", index);
69 	seq_printf(m, "vendor_id\t: User Mode Linux\n");
70 	seq_printf(m, "model name\t: UML\n");
71 	seq_printf(m, "mode\t\t: skas\n");
72 	seq_printf(m, "host\t\t: %s\n", host_info);
73 	seq_printf(m, "bogomips\t: %lu.%02lu\n\n",
74 		   loops_per_jiffy/(500000/HZ),
75 		   (loops_per_jiffy/(5000/HZ)) % 100);
76 
77 	return 0;
78 }
79 
80 static void *c_start(struct seq_file *m, loff_t *pos)
81 {
82 	return *pos < NR_CPUS ? cpu_data + *pos : NULL;
83 }
84 
85 static void *c_next(struct seq_file *m, void *v, loff_t *pos)
86 {
87 	++*pos;
88 	return c_start(m, pos);
89 }
90 
91 static void c_stop(struct seq_file *m, void *v)
92 {
93 }
94 
95 const struct seq_operations cpuinfo_op = {
96 	.start	= c_start,
97 	.next	= c_next,
98 	.stop	= c_stop,
99 	.show	= show_cpuinfo,
100 };
101 
102 /* Set in linux_main */
103 unsigned long host_task_size;
104 unsigned long task_size;
105 unsigned long uml_physmem;
106 unsigned long uml_reserved; /* Also modified in mem_init */
107 unsigned long start_vm;
108 unsigned long end_vm;
109 
110 /* Set in uml_ncpus_setup */
111 int ncpus = 1;
112 
113 /* Set in early boot */
114 static int have_root __initdata = 0;
115 
116 /* Set in uml_mem_setup and modified in linux_main */
117 long long physmem_size = 32 * 1024 * 1024;
118 
119 static char *usage_string =
120 "User Mode Linux v%s\n"
121 "	available at http://user-mode-linux.sourceforge.net/\n\n";
122 
123 static int __init uml_version_setup(char *line, int *add)
124 {
125 	printf("%s\n", init_utsname()->release);
126 	exit(0);
127 
128 	return 0;
129 }
130 
131 __uml_setup("--version", uml_version_setup,
132 "--version\n"
133 "    Prints the version number of the kernel.\n\n"
134 );
135 
136 static int __init uml_root_setup(char *line, int *add)
137 {
138 	have_root = 1;
139 	return 0;
140 }
141 
142 __uml_setup("root=", uml_root_setup,
143 "root=<file containing the root fs>\n"
144 "    This is actually used by the generic kernel in exactly the same\n"
145 "    way as in any other kernel. If you configure a number of block\n"
146 "    devices and want to boot off something other than ubd0, you \n"
147 "    would use something like:\n"
148 "        root=/dev/ubd5\n\n"
149 );
150 
151 static int __init no_skas_debug_setup(char *line, int *add)
152 {
153 	printf("'debug' is not necessary to gdb UML in skas mode - run \n");
154 	printf("'gdb linux'");
155 
156 	return 0;
157 }
158 
159 __uml_setup("debug", no_skas_debug_setup,
160 "debug\n"
161 "    this flag is not needed to run gdb on UML in skas mode\n\n"
162 );
163 
164 #ifdef CONFIG_SMP
165 static int __init uml_ncpus_setup(char *line, int *add)
166 {
167 	if (!sscanf(line, "%d", &ncpus)) {
168 		printf("Couldn't parse [%s]\n", line);
169 		return -1;
170 	}
171 
172 	return 0;
173 }
174 
175 __uml_setup("ncpus=", uml_ncpus_setup,
176 "ncpus=<# of desired CPUs>\n"
177 "    This tells an SMP kernel how many virtual processors to start.\n\n"
178 );
179 #endif
180 
181 static int __init Usage(char *line, int *add)
182 {
183 	const char **p;
184 
185 	printf(usage_string, init_utsname()->release);
186 	p = &__uml_help_start;
187 	while (p < &__uml_help_end) {
188 		printf("%s", *p);
189 		p++;
190 	}
191 	exit(0);
192 	return 0;
193 }
194 
195 __uml_setup("--help", Usage,
196 "--help\n"
197 "    Prints this message.\n\n"
198 );
199 
200 static int __init uml_checksetup(char *line, int *add)
201 {
202 	struct uml_param *p;
203 
204 	p = &__uml_setup_start;
205 	while(p < &__uml_setup_end) {
206 		int n;
207 
208 		n = strlen(p->str);
209 		if (!strncmp(line, p->str, n) && p->setup_func(line + n, add))
210 			return 1;
211 		p++;
212 	}
213 	return 0;
214 }
215 
216 static void __init uml_postsetup(void)
217 {
218 	initcall_t *p;
219 
220 	p = &__uml_postsetup_start;
221 	while(p < &__uml_postsetup_end) {
222 		(*p)();
223 		p++;
224 	}
225 	return;
226 }
227 
228 /* Set during early boot */
229 unsigned long brk_start;
230 unsigned long end_iomem;
231 EXPORT_SYMBOL(end_iomem);
232 
233 #define MIN_VMALLOC (32 * 1024 * 1024)
234 
235 extern char __binary_start;
236 
237 static unsigned long set_task_sizes_skas(unsigned long *task_size_out)
238 {
239 	/* Round up to the nearest 4M */
240 	unsigned long host_task_size = ROUND_4M((unsigned long)
241 						&host_task_size);
242 
243 	if (!skas_needs_stub)
244 		*task_size_out = host_task_size;
245 	else
246 		*task_size_out = STUB_START & PGDIR_MASK;
247 
248 	return host_task_size;
249 }
250 
251 int __init linux_main(int argc, char **argv)
252 {
253 	unsigned long avail, diff;
254 	unsigned long virtmem_size, max_physmem;
255 	unsigned int i, add;
256 	char * mode;
257 
258 	for (i = 1; i < argc; i++) {
259 		if ((i == 1) && (argv[i][0] == ' '))
260 			continue;
261 		add = 1;
262 		uml_checksetup(argv[i], &add);
263 		if (add)
264 			add_arg(argv[i]);
265 	}
266 	if (have_root == 0)
267 		add_arg(DEFAULT_COMMAND_LINE);
268 
269 	/* OS sanity checks that need to happen before the kernel runs */
270 	os_early_checks();
271 
272 	can_do_skas();
273 
274 	if (proc_mm && ptrace_faultinfo)
275 		mode = "SKAS3";
276 	else
277 		mode = "SKAS0";
278 
279 	printf("UML running in %s mode\n", mode);
280 
281 	host_task_size = set_task_sizes_skas(&task_size);
282 
283 	/*
284 	 * Setting up handlers to 'sig_info' struct
285 	 */
286 	os_fill_handlinfo(handlinfo_kern);
287 
288 	brk_start = (unsigned long) sbrk(0);
289 
290 	/*
291 	 * Increase physical memory size for exec-shield users
292 	 * so they actually get what they asked for. This should
293 	 * add zero for non-exec shield users
294 	 */
295 
296 	diff = UML_ROUND_UP(brk_start) - UML_ROUND_UP(&_end);
297 	if (diff > 1024 * 1024) {
298 		printf("Adding %ld bytes to physical memory to account for "
299 		       "exec-shield gap\n", diff);
300 		physmem_size += UML_ROUND_UP(brk_start) - UML_ROUND_UP(&_end);
301 	}
302 
303 	uml_physmem = (unsigned long) &__binary_start & PAGE_MASK;
304 
305 	/* Reserve up to 4M after the current brk */
306 	uml_reserved = ROUND_4M(brk_start) + (1 << 22);
307 
308 	setup_machinename(init_utsname()->machine);
309 
310 	highmem = 0;
311 	iomem_size = (iomem_size + PAGE_SIZE - 1) & PAGE_MASK;
312 	max_physmem = get_kmem_end() - uml_physmem - iomem_size - MIN_VMALLOC;
313 
314 	/*
315 	 * Zones have to begin on a 1 << MAX_ORDER page boundary,
316 	 * so this makes sure that's true for highmem
317 	 */
318 	max_physmem &= ~((1 << (PAGE_SHIFT + MAX_ORDER)) - 1);
319 	if (physmem_size + iomem_size > max_physmem) {
320 		highmem = physmem_size + iomem_size - max_physmem;
321 		physmem_size -= highmem;
322 #ifndef CONFIG_HIGHMEM
323 		highmem = 0;
324 		printf("CONFIG_HIGHMEM not enabled - physical memory shrunk "
325 		       "to %Lu bytes\n", physmem_size);
326 #endif
327 	}
328 
329 	high_physmem = uml_physmem + physmem_size;
330 	end_iomem = high_physmem + iomem_size;
331 	high_memory = (void *) end_iomem;
332 
333 	start_vm = VMALLOC_START;
334 
335 	setup_physmem(uml_physmem, uml_reserved, physmem_size, highmem);
336 	if (init_maps(physmem_size, iomem_size, highmem)) {
337 		printf("Failed to allocate mem_map for %Lu bytes of physical "
338 		       "memory and %Lu bytes of highmem\n", physmem_size,
339 		       highmem);
340 		exit(1);
341 	}
342 
343 	virtmem_size = physmem_size;
344 	avail = get_kmem_end() - start_vm;
345 	if (physmem_size > avail)
346 		virtmem_size = avail;
347 	end_vm = start_vm + virtmem_size;
348 
349 	if (virtmem_size < physmem_size)
350 		printf("Kernel virtual memory size shrunk to %lu bytes\n",
351 		       virtmem_size);
352 
353 	uml_postsetup();
354 
355 	stack_protections((unsigned long) &init_thread_info);
356 	os_flush_stdout();
357 
358 	return start_uml();
359 }
360 
361 extern int uml_exitcode;
362 
363 static int panic_exit(struct notifier_block *self, unsigned long unused1,
364 		      void *unused2)
365 {
366 	bust_spinlocks(1);
367 	show_regs(&(current->thread.regs));
368 	bust_spinlocks(0);
369 	uml_exitcode = 1;
370 	os_dump_core();
371 	return 0;
372 }
373 
374 static struct notifier_block panic_exit_notifier = {
375 	.notifier_call 		= panic_exit,
376 	.next 			= NULL,
377 	.priority 		= 0
378 };
379 
380 void __init setup_arch(char **cmdline_p)
381 {
382 	atomic_notifier_chain_register(&panic_notifier_list,
383 			&panic_exit_notifier);
384 	paging_init();
385 	strlcpy(boot_command_line, command_line, COMMAND_LINE_SIZE);
386 	*cmdline_p = command_line;
387 	setup_hostinfo(host_info, sizeof host_info);
388 }
389 
390 void __init check_bugs(void)
391 {
392 	arch_check_bugs();
393 	os_check_bugs();
394 }
395 
396 void apply_alternatives(struct alt_instr *start, struct alt_instr *end)
397 {
398 }
399 
400 #ifdef CONFIG_SMP
401 void alternatives_smp_module_add(struct module *mod, char *name,
402 				 void *locks, void *locks_end,
403 				 void *text,  void *text_end)
404 {
405 }
406 
407 void alternatives_smp_module_del(struct module *mod)
408 {
409 }
410 #endif
411