xref: /openbmc/linux/arch/um/kernel/um_arch.c (revision a06c488d)
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 <linux/kmsg_dump.h>
15 #include <asm/pgtable.h>
16 #include <asm/processor.h>
17 #include <asm/sections.h>
18 #include <asm/setup.h>
19 #include <as-layout.h>
20 #include <arch.h>
21 #include <init.h>
22 #include <kern.h>
23 #include <kern_util.h>
24 #include <mem_user.h>
25 #include <os.h>
26 
27 #define DEFAULT_COMMAND_LINE "root=98:0"
28 
29 /* Changed in add_arg and setup_arch, which run before SMP is started */
30 static char __initdata command_line[COMMAND_LINE_SIZE] = { 0 };
31 
32 static void __init add_arg(char *arg)
33 {
34 	if (strlen(command_line) + strlen(arg) + 1 > COMMAND_LINE_SIZE) {
35 		printf("add_arg: Too many command line arguments!\n");
36 		exit(1);
37 	}
38 	if (strlen(command_line) > 0)
39 		strcat(command_line, " ");
40 	strcat(command_line, arg);
41 }
42 
43 /*
44  * These fields are initialized at boot time and not changed.
45  * XXX This structure is used only in the non-SMP case.  Maybe this
46  * should be moved to smp.c.
47  */
48 struct cpuinfo_um boot_cpu_data = {
49 	.loops_per_jiffy	= 0,
50 	.ipi_pipe		= { -1, -1 }
51 };
52 
53 union thread_union cpu0_irqstack
54 	__attribute__((__section__(".data..init_irqstack"))) =
55 		{ INIT_THREAD_INFO(init_task) };
56 
57 unsigned long thread_saved_pc(struct task_struct *task)
58 {
59 	/* FIXME: Need to look up userspace_pid by cpu */
60 	return os_process_pc(userspace_pid[0]);
61 }
62 
63 /* Changed in setup_arch, which is called in early boot */
64 static char host_info[(__NEW_UTS_LEN + 1) * 5];
65 
66 static int show_cpuinfo(struct seq_file *m, void *v)
67 {
68 	int index = 0;
69 
70 	seq_printf(m, "processor\t: %d\n", index);
71 	seq_printf(m, "vendor_id\t: User Mode Linux\n");
72 	seq_printf(m, "model name\t: UML\n");
73 	seq_printf(m, "mode\t\t: skas\n");
74 	seq_printf(m, "host\t\t: %s\n", host_info);
75 	seq_printf(m, "bogomips\t: %lu.%02lu\n\n",
76 		   loops_per_jiffy/(500000/HZ),
77 		   (loops_per_jiffy/(5000/HZ)) % 100);
78 
79 	return 0;
80 }
81 
82 static void *c_start(struct seq_file *m, loff_t *pos)
83 {
84 	return *pos < NR_CPUS ? cpu_data + *pos : NULL;
85 }
86 
87 static void *c_next(struct seq_file *m, void *v, loff_t *pos)
88 {
89 	++*pos;
90 	return c_start(m, pos);
91 }
92 
93 static void c_stop(struct seq_file *m, void *v)
94 {
95 }
96 
97 const struct seq_operations cpuinfo_op = {
98 	.start	= c_start,
99 	.next	= c_next,
100 	.stop	= c_stop,
101 	.show	= show_cpuinfo,
102 };
103 
104 /* Set in linux_main */
105 unsigned long uml_physmem;
106 EXPORT_SYMBOL(uml_physmem);
107 
108 unsigned long uml_reserved; /* Also modified in mem_init */
109 unsigned long start_vm;
110 unsigned long end_vm;
111 
112 /* Set in uml_ncpus_setup */
113 int ncpus = 1;
114 
115 /* Set in early boot */
116 static int have_root __initdata = 0;
117 
118 /* Set in uml_mem_setup and modified in linux_main */
119 long long physmem_size = 32 * 1024 * 1024;
120 
121 static const char *usage_string =
122 "User Mode Linux v%s\n"
123 "	available at http://user-mode-linux.sourceforge.net/\n\n";
124 
125 static int __init uml_version_setup(char *line, int *add)
126 {
127 	printf("%s\n", init_utsname()->release);
128 	exit(0);
129 
130 	return 0;
131 }
132 
133 __uml_setup("--version", uml_version_setup,
134 "--version\n"
135 "    Prints the version number of the kernel.\n\n"
136 );
137 
138 static int __init uml_root_setup(char *line, int *add)
139 {
140 	have_root = 1;
141 	return 0;
142 }
143 
144 __uml_setup("root=", uml_root_setup,
145 "root=<file containing the root fs>\n"
146 "    This is actually used by the generic kernel in exactly the same\n"
147 "    way as in any other kernel. If you configure a number of block\n"
148 "    devices and want to boot off something other than ubd0, you \n"
149 "    would use something like:\n"
150 "        root=/dev/ubd5\n\n"
151 );
152 
153 static int __init no_skas_debug_setup(char *line, int *add)
154 {
155 	printf("'debug' is not necessary to gdb UML in skas mode - run \n");
156 	printf("'gdb linux'\n");
157 
158 	return 0;
159 }
160 
161 __uml_setup("debug", no_skas_debug_setup,
162 "debug\n"
163 "    this flag is not needed to run gdb on UML in skas mode\n\n"
164 );
165 
166 static int __init Usage(char *line, int *add)
167 {
168 	const char **p;
169 
170 	printf(usage_string, init_utsname()->release);
171 	p = &__uml_help_start;
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 
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 
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 
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 
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 
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 		printf("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 	setup_physmem(uml_physmem, uml_reserved, physmem_size, highmem);
323 	mem_total_pages(physmem_size, iomem_size, highmem);
324 
325 	virtmem_size = physmem_size;
326 	stack = (unsigned long) argv;
327 	stack &= ~(1024 * 1024 - 1);
328 	avail = stack - start_vm;
329 	if (physmem_size > avail)
330 		virtmem_size = avail;
331 	end_vm = start_vm + virtmem_size;
332 
333 	if (virtmem_size < physmem_size)
334 		printf("Kernel virtual memory size shrunk to %lu bytes\n",
335 		       virtmem_size);
336 
337 	stack_protections((unsigned long) &init_thread_info);
338 	os_flush_stdout();
339 
340 	return start_uml();
341 }
342 
343 void __init setup_arch(char **cmdline_p)
344 {
345 	paging_init();
346 	strlcpy(boot_command_line, command_line, COMMAND_LINE_SIZE);
347 	*cmdline_p = command_line;
348 	setup_hostinfo(host_info, sizeof host_info);
349 }
350 
351 void __init check_bugs(void)
352 {
353 	arch_check_bugs();
354 	os_check_bugs();
355 }
356 
357 void apply_alternatives(struct alt_instr *start, struct alt_instr *end)
358 {
359 }
360