xref: /openbmc/linux/arch/s390/kernel/setup.c (revision 81d67439)
1 /*
2  *  arch/s390/kernel/setup.c
3  *
4  *  S390 version
5  *    Copyright (C) IBM Corp. 1999,2010
6  *    Author(s): Hartmut Penner (hp@de.ibm.com),
7  *               Martin Schwidefsky (schwidefsky@de.ibm.com)
8  *
9  *  Derived from "arch/i386/kernel/setup.c"
10  *    Copyright (C) 1995, Linus Torvalds
11  */
12 
13 /*
14  * This file handles the architecture-dependent parts of initialization
15  */
16 
17 #define KMSG_COMPONENT "setup"
18 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
19 
20 #include <linux/errno.h>
21 #include <linux/module.h>
22 #include <linux/sched.h>
23 #include <linux/kernel.h>
24 #include <linux/mm.h>
25 #include <linux/stddef.h>
26 #include <linux/unistd.h>
27 #include <linux/ptrace.h>
28 #include <linux/user.h>
29 #include <linux/tty.h>
30 #include <linux/ioport.h>
31 #include <linux/delay.h>
32 #include <linux/init.h>
33 #include <linux/initrd.h>
34 #include <linux/bootmem.h>
35 #include <linux/root_dev.h>
36 #include <linux/console.h>
37 #include <linux/kernel_stat.h>
38 #include <linux/device.h>
39 #include <linux/notifier.h>
40 #include <linux/pfn.h>
41 #include <linux/ctype.h>
42 #include <linux/reboot.h>
43 #include <linux/topology.h>
44 #include <linux/ftrace.h>
45 
46 #include <asm/ipl.h>
47 #include <asm/uaccess.h>
48 #include <asm/system.h>
49 #include <asm/smp.h>
50 #include <asm/mmu_context.h>
51 #include <asm/cpcmd.h>
52 #include <asm/lowcore.h>
53 #include <asm/irq.h>
54 #include <asm/page.h>
55 #include <asm/ptrace.h>
56 #include <asm/sections.h>
57 #include <asm/ebcdic.h>
58 #include <asm/compat.h>
59 #include <asm/kvm_virtio.h>
60 
61 long psw_kernel_bits	= (PSW_BASE_BITS | PSW_MASK_DAT | PSW_ASC_PRIMARY |
62 			   PSW_MASK_MCHECK | PSW_DEFAULT_KEY);
63 long psw_user_bits	= (PSW_BASE_BITS | PSW_MASK_DAT | PSW_ASC_HOME |
64 			   PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK |
65 			   PSW_MASK_PSTATE | PSW_DEFAULT_KEY);
66 
67 /*
68  * User copy operations.
69  */
70 struct uaccess_ops uaccess;
71 EXPORT_SYMBOL(uaccess);
72 
73 /*
74  * Machine setup..
75  */
76 unsigned int console_mode = 0;
77 EXPORT_SYMBOL(console_mode);
78 
79 unsigned int console_devno = -1;
80 EXPORT_SYMBOL(console_devno);
81 
82 unsigned int console_irq = -1;
83 EXPORT_SYMBOL(console_irq);
84 
85 unsigned long elf_hwcap = 0;
86 char elf_platform[ELF_PLATFORM_SIZE];
87 
88 struct mem_chunk __initdata memory_chunk[MEMORY_CHUNKS];
89 
90 int __initdata memory_end_set;
91 unsigned long __initdata memory_end;
92 
93 /* An array with a pointer to the lowcore of every CPU. */
94 struct _lowcore *lowcore_ptr[NR_CPUS];
95 EXPORT_SYMBOL(lowcore_ptr);
96 
97 /*
98  * This is set up by the setup-routine at boot-time
99  * for S390 need to find out, what we have to setup
100  * using address 0x10400 ...
101  */
102 
103 #include <asm/setup.h>
104 
105 /*
106  * condev= and conmode= setup parameter.
107  */
108 
109 static int __init condev_setup(char *str)
110 {
111 	int vdev;
112 
113 	vdev = simple_strtoul(str, &str, 0);
114 	if (vdev >= 0 && vdev < 65536) {
115 		console_devno = vdev;
116 		console_irq = -1;
117 	}
118 	return 1;
119 }
120 
121 __setup("condev=", condev_setup);
122 
123 static void __init set_preferred_console(void)
124 {
125 	if (MACHINE_IS_KVM)
126 		add_preferred_console("hvc", 0, NULL);
127 	else if (CONSOLE_IS_3215 || CONSOLE_IS_SCLP)
128 		add_preferred_console("ttyS", 0, NULL);
129 	else if (CONSOLE_IS_3270)
130 		add_preferred_console("tty3270", 0, NULL);
131 }
132 
133 static int __init conmode_setup(char *str)
134 {
135 #if defined(CONFIG_SCLP_CONSOLE) || defined(CONFIG_SCLP_VT220_CONSOLE)
136 	if (strncmp(str, "hwc", 4) == 0 || strncmp(str, "sclp", 5) == 0)
137                 SET_CONSOLE_SCLP;
138 #endif
139 #if defined(CONFIG_TN3215_CONSOLE)
140 	if (strncmp(str, "3215", 5) == 0)
141 		SET_CONSOLE_3215;
142 #endif
143 #if defined(CONFIG_TN3270_CONSOLE)
144 	if (strncmp(str, "3270", 5) == 0)
145 		SET_CONSOLE_3270;
146 #endif
147 	set_preferred_console();
148         return 1;
149 }
150 
151 __setup("conmode=", conmode_setup);
152 
153 static void __init conmode_default(void)
154 {
155 	char query_buffer[1024];
156 	char *ptr;
157 
158         if (MACHINE_IS_VM) {
159 		cpcmd("QUERY CONSOLE", query_buffer, 1024, NULL);
160 		console_devno = simple_strtoul(query_buffer + 5, NULL, 16);
161 		ptr = strstr(query_buffer, "SUBCHANNEL =");
162 		console_irq = simple_strtoul(ptr + 13, NULL, 16);
163 		cpcmd("QUERY TERM", query_buffer, 1024, NULL);
164 		ptr = strstr(query_buffer, "CONMODE");
165 		/*
166 		 * Set the conmode to 3215 so that the device recognition
167 		 * will set the cu_type of the console to 3215. If the
168 		 * conmode is 3270 and we don't set it back then both
169 		 * 3215 and the 3270 driver will try to access the console
170 		 * device (3215 as console and 3270 as normal tty).
171 		 */
172 		cpcmd("TERM CONMODE 3215", NULL, 0, NULL);
173 		if (ptr == NULL) {
174 #if defined(CONFIG_SCLP_CONSOLE) || defined(CONFIG_SCLP_VT220_CONSOLE)
175 			SET_CONSOLE_SCLP;
176 #endif
177 			return;
178 		}
179 		if (strncmp(ptr + 8, "3270", 4) == 0) {
180 #if defined(CONFIG_TN3270_CONSOLE)
181 			SET_CONSOLE_3270;
182 #elif defined(CONFIG_TN3215_CONSOLE)
183 			SET_CONSOLE_3215;
184 #elif defined(CONFIG_SCLP_CONSOLE) || defined(CONFIG_SCLP_VT220_CONSOLE)
185 			SET_CONSOLE_SCLP;
186 #endif
187 		} else if (strncmp(ptr + 8, "3215", 4) == 0) {
188 #if defined(CONFIG_TN3215_CONSOLE)
189 			SET_CONSOLE_3215;
190 #elif defined(CONFIG_TN3270_CONSOLE)
191 			SET_CONSOLE_3270;
192 #elif defined(CONFIG_SCLP_CONSOLE) || defined(CONFIG_SCLP_VT220_CONSOLE)
193 			SET_CONSOLE_SCLP;
194 #endif
195 		}
196 	} else {
197 #if defined(CONFIG_SCLP_CONSOLE) || defined(CONFIG_SCLP_VT220_CONSOLE)
198 		SET_CONSOLE_SCLP;
199 #endif
200 	}
201 }
202 
203 #ifdef CONFIG_ZFCPDUMP
204 static void __init setup_zfcpdump(unsigned int console_devno)
205 {
206 	static char str[41];
207 
208 	if (ipl_info.type != IPL_TYPE_FCP_DUMP)
209 		return;
210 	if (console_devno != -1)
211 		sprintf(str, " cio_ignore=all,!0.0.%04x,!0.0.%04x",
212 			ipl_info.data.fcp.dev_id.devno, console_devno);
213 	else
214 		sprintf(str, " cio_ignore=all,!0.0.%04x",
215 			ipl_info.data.fcp.dev_id.devno);
216 	strcat(boot_command_line, str);
217 	console_loglevel = 2;
218 }
219 #else
220 static inline void setup_zfcpdump(unsigned int console_devno) {}
221 #endif /* CONFIG_ZFCPDUMP */
222 
223  /*
224  * Reboot, halt and power_off stubs. They just call _machine_restart,
225  * _machine_halt or _machine_power_off.
226  */
227 
228 void machine_restart(char *command)
229 {
230 	if ((!in_interrupt() && !in_atomic()) || oops_in_progress)
231 		/*
232 		 * Only unblank the console if we are called in enabled
233 		 * context or a bust_spinlocks cleared the way for us.
234 		 */
235 		console_unblank();
236 	_machine_restart(command);
237 }
238 
239 void machine_halt(void)
240 {
241 	if (!in_interrupt() || oops_in_progress)
242 		/*
243 		 * Only unblank the console if we are called in enabled
244 		 * context or a bust_spinlocks cleared the way for us.
245 		 */
246 		console_unblank();
247 	_machine_halt();
248 }
249 
250 void machine_power_off(void)
251 {
252 	if (!in_interrupt() || oops_in_progress)
253 		/*
254 		 * Only unblank the console if we are called in enabled
255 		 * context or a bust_spinlocks cleared the way for us.
256 		 */
257 		console_unblank();
258 	_machine_power_off();
259 }
260 
261 /*
262  * Dummy power off function.
263  */
264 void (*pm_power_off)(void) = machine_power_off;
265 
266 static int __init early_parse_mem(char *p)
267 {
268 	memory_end = memparse(p, &p);
269 	memory_end_set = 1;
270 	return 0;
271 }
272 early_param("mem", early_parse_mem);
273 
274 unsigned int user_mode = HOME_SPACE_MODE;
275 EXPORT_SYMBOL_GPL(user_mode);
276 
277 static int set_amode_and_uaccess(unsigned long user_amode,
278 				 unsigned long user32_amode)
279 {
280 	psw_user_bits = PSW_BASE_BITS | PSW_MASK_DAT | user_amode |
281 			PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK |
282 			PSW_MASK_PSTATE | PSW_DEFAULT_KEY;
283 #ifdef CONFIG_COMPAT
284 	psw_user32_bits = PSW_BASE32_BITS | PSW_MASK_DAT | user_amode |
285 			  PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK |
286 			  PSW_MASK_PSTATE | PSW_DEFAULT_KEY;
287 	psw32_user_bits = PSW32_BASE_BITS | PSW32_MASK_DAT | user32_amode |
288 			  PSW32_MASK_IO | PSW32_MASK_EXT | PSW32_MASK_MCHECK |
289 			  PSW32_MASK_PSTATE;
290 #endif
291 	psw_kernel_bits = PSW_BASE_BITS | PSW_MASK_DAT | PSW_ASC_HOME |
292 			  PSW_MASK_MCHECK | PSW_DEFAULT_KEY;
293 
294 	if (MACHINE_HAS_MVCOS) {
295 		memcpy(&uaccess, &uaccess_mvcos_switch, sizeof(uaccess));
296 		return 1;
297 	} else {
298 		memcpy(&uaccess, &uaccess_pt, sizeof(uaccess));
299 		return 0;
300 	}
301 }
302 
303 /*
304  * Switch kernel/user addressing modes?
305  */
306 static int __init early_parse_switch_amode(char *p)
307 {
308 	user_mode = PRIMARY_SPACE_MODE;
309 	return 0;
310 }
311 early_param("switch_amode", early_parse_switch_amode);
312 
313 static int __init early_parse_user_mode(char *p)
314 {
315 	if (p && strcmp(p, "primary") == 0)
316 		user_mode = PRIMARY_SPACE_MODE;
317 	else if (!p || strcmp(p, "home") == 0)
318 		user_mode = HOME_SPACE_MODE;
319 	else
320 		return 1;
321 	return 0;
322 }
323 early_param("user_mode", early_parse_user_mode);
324 
325 static void setup_addressing_mode(void)
326 {
327 	if (user_mode == PRIMARY_SPACE_MODE) {
328 		if (set_amode_and_uaccess(PSW_ASC_PRIMARY, PSW32_ASC_PRIMARY))
329 			pr_info("Address spaces switched, "
330 				"mvcos available\n");
331 		else
332 			pr_info("Address spaces switched, "
333 				"mvcos not available\n");
334 	}
335 }
336 
337 static void __init
338 setup_lowcore(void)
339 {
340 	struct _lowcore *lc;
341 
342 	/*
343 	 * Setup lowcore for boot cpu
344 	 */
345 	BUILD_BUG_ON(sizeof(struct _lowcore) != LC_PAGES * 4096);
346 	lc = __alloc_bootmem_low(LC_PAGES * PAGE_SIZE, LC_PAGES * PAGE_SIZE, 0);
347 	lc->restart_psw.mask = PSW_BASE_BITS | PSW_DEFAULT_KEY;
348 	lc->restart_psw.addr =
349 		PSW_ADDR_AMODE | (unsigned long) restart_int_handler;
350 	if (user_mode != HOME_SPACE_MODE)
351 		lc->restart_psw.mask |= PSW_ASC_HOME;
352 	lc->external_new_psw.mask = psw_kernel_bits;
353 	lc->external_new_psw.addr =
354 		PSW_ADDR_AMODE | (unsigned long) ext_int_handler;
355 	lc->svc_new_psw.mask = psw_kernel_bits | PSW_MASK_IO | PSW_MASK_EXT;
356 	lc->svc_new_psw.addr = PSW_ADDR_AMODE | (unsigned long) system_call;
357 	lc->program_new_psw.mask = psw_kernel_bits;
358 	lc->program_new_psw.addr =
359 		PSW_ADDR_AMODE | (unsigned long)pgm_check_handler;
360 	lc->mcck_new_psw.mask =
361 		psw_kernel_bits & ~PSW_MASK_MCHECK & ~PSW_MASK_DAT;
362 	lc->mcck_new_psw.addr =
363 		PSW_ADDR_AMODE | (unsigned long) mcck_int_handler;
364 	lc->io_new_psw.mask = psw_kernel_bits;
365 	lc->io_new_psw.addr = PSW_ADDR_AMODE | (unsigned long) io_int_handler;
366 	lc->clock_comparator = -1ULL;
367 	lc->kernel_stack = ((unsigned long) &init_thread_union) + THREAD_SIZE;
368 	lc->async_stack = (unsigned long)
369 		__alloc_bootmem(ASYNC_SIZE, ASYNC_SIZE, 0) + ASYNC_SIZE;
370 	lc->panic_stack = (unsigned long)
371 		__alloc_bootmem(PAGE_SIZE, PAGE_SIZE, 0) + PAGE_SIZE;
372 	lc->current_task = (unsigned long) init_thread_union.thread_info.task;
373 	lc->thread_info = (unsigned long) &init_thread_union;
374 	lc->machine_flags = S390_lowcore.machine_flags;
375 	lc->stfl_fac_list = S390_lowcore.stfl_fac_list;
376 	memcpy(lc->stfle_fac_list, S390_lowcore.stfle_fac_list,
377 	       MAX_FACILITY_BIT/8);
378 #ifndef CONFIG_64BIT
379 	if (MACHINE_HAS_IEEE) {
380 		lc->extended_save_area_addr = (__u32)
381 			__alloc_bootmem_low(PAGE_SIZE, PAGE_SIZE, 0);
382 		/* enable extended save area */
383 		__ctl_set_bit(14, 29);
384 	}
385 #else
386 	lc->cmf_hpp = -1ULL;
387 	lc->vdso_per_cpu_data = (unsigned long) &lc->paste[0];
388 #endif
389 	lc->sync_enter_timer = S390_lowcore.sync_enter_timer;
390 	lc->async_enter_timer = S390_lowcore.async_enter_timer;
391 	lc->exit_timer = S390_lowcore.exit_timer;
392 	lc->user_timer = S390_lowcore.user_timer;
393 	lc->system_timer = S390_lowcore.system_timer;
394 	lc->steal_timer = S390_lowcore.steal_timer;
395 	lc->last_update_timer = S390_lowcore.last_update_timer;
396 	lc->last_update_clock = S390_lowcore.last_update_clock;
397 	lc->ftrace_func = S390_lowcore.ftrace_func;
398 	set_prefix((u32)(unsigned long) lc);
399 	lowcore_ptr[0] = lc;
400 }
401 
402 static struct resource code_resource = {
403 	.name  = "Kernel code",
404 	.flags = IORESOURCE_BUSY | IORESOURCE_MEM,
405 };
406 
407 static struct resource data_resource = {
408 	.name = "Kernel data",
409 	.flags = IORESOURCE_BUSY | IORESOURCE_MEM,
410 };
411 
412 static struct resource bss_resource = {
413 	.name = "Kernel bss",
414 	.flags = IORESOURCE_BUSY | IORESOURCE_MEM,
415 };
416 
417 static struct resource __initdata *standard_resources[] = {
418 	&code_resource,
419 	&data_resource,
420 	&bss_resource,
421 };
422 
423 static void __init setup_resources(void)
424 {
425 	struct resource *res, *std_res, *sub_res;
426 	int i, j;
427 
428 	code_resource.start = (unsigned long) &_text;
429 	code_resource.end = (unsigned long) &_etext - 1;
430 	data_resource.start = (unsigned long) &_etext;
431 	data_resource.end = (unsigned long) &_edata - 1;
432 	bss_resource.start = (unsigned long) &__bss_start;
433 	bss_resource.end = (unsigned long) &__bss_stop - 1;
434 
435 	for (i = 0; i < MEMORY_CHUNKS; i++) {
436 		if (!memory_chunk[i].size)
437 			continue;
438 		res = alloc_bootmem_low(sizeof(*res));
439 		res->flags = IORESOURCE_BUSY | IORESOURCE_MEM;
440 		switch (memory_chunk[i].type) {
441 		case CHUNK_READ_WRITE:
442 			res->name = "System RAM";
443 			break;
444 		case CHUNK_READ_ONLY:
445 			res->name = "System ROM";
446 			res->flags |= IORESOURCE_READONLY;
447 			break;
448 		default:
449 			res->name = "reserved";
450 		}
451 		res->start = memory_chunk[i].addr;
452 		res->end = res->start + memory_chunk[i].size - 1;
453 		request_resource(&iomem_resource, res);
454 
455 		for (j = 0; j < ARRAY_SIZE(standard_resources); j++) {
456 			std_res = standard_resources[j];
457 			if (std_res->start < res->start ||
458 			    std_res->start > res->end)
459 				continue;
460 			if (std_res->end > res->end) {
461 				sub_res = alloc_bootmem_low(sizeof(*sub_res));
462 				*sub_res = *std_res;
463 				sub_res->end = res->end;
464 				std_res->start = res->end + 1;
465 				request_resource(res, sub_res);
466 			} else {
467 				request_resource(res, std_res);
468 			}
469 		}
470 	}
471 }
472 
473 unsigned long real_memory_size;
474 EXPORT_SYMBOL_GPL(real_memory_size);
475 
476 static void __init setup_memory_end(void)
477 {
478 	unsigned long memory_size;
479 	unsigned long max_mem;
480 	int i;
481 
482 #ifdef CONFIG_ZFCPDUMP
483 	if (ipl_info.type == IPL_TYPE_FCP_DUMP) {
484 		memory_end = ZFCPDUMP_HSA_SIZE;
485 		memory_end_set = 1;
486 	}
487 #endif
488 	memory_size = 0;
489 	memory_end &= PAGE_MASK;
490 
491 	max_mem = memory_end ? min(VMEM_MAX_PHYS, memory_end) : VMEM_MAX_PHYS;
492 	memory_end = min(max_mem, memory_end);
493 
494 	/*
495 	 * Make sure all chunks are MAX_ORDER aligned so we don't need the
496 	 * extra checks that HOLES_IN_ZONE would require.
497 	 */
498 	for (i = 0; i < MEMORY_CHUNKS; i++) {
499 		unsigned long start, end;
500 		struct mem_chunk *chunk;
501 		unsigned long align;
502 
503 		chunk = &memory_chunk[i];
504 		align = 1UL << (MAX_ORDER + PAGE_SHIFT - 1);
505 		start = (chunk->addr + align - 1) & ~(align - 1);
506 		end = (chunk->addr + chunk->size) & ~(align - 1);
507 		if (start >= end)
508 			memset(chunk, 0, sizeof(*chunk));
509 		else {
510 			chunk->addr = start;
511 			chunk->size = end - start;
512 		}
513 	}
514 
515 	for (i = 0; i < MEMORY_CHUNKS; i++) {
516 		struct mem_chunk *chunk = &memory_chunk[i];
517 
518 		real_memory_size = max(real_memory_size,
519 				       chunk->addr + chunk->size);
520 		if (chunk->addr >= max_mem) {
521 			memset(chunk, 0, sizeof(*chunk));
522 			continue;
523 		}
524 		if (chunk->addr + chunk->size > max_mem)
525 			chunk->size = max_mem - chunk->addr;
526 		memory_size = max(memory_size, chunk->addr + chunk->size);
527 	}
528 	if (!memory_end)
529 		memory_end = memory_size;
530 }
531 
532 static void __init
533 setup_memory(void)
534 {
535         unsigned long bootmap_size;
536 	unsigned long start_pfn, end_pfn;
537 	int i;
538 
539 	/*
540 	 * partially used pages are not usable - thus
541 	 * we are rounding upwards:
542 	 */
543 	start_pfn = PFN_UP(__pa(&_end));
544 	end_pfn = max_pfn = PFN_DOWN(memory_end);
545 
546 #ifdef CONFIG_BLK_DEV_INITRD
547 	/*
548 	 * Move the initrd in case the bitmap of the bootmem allocater
549 	 * would overwrite it.
550 	 */
551 
552 	if (INITRD_START && INITRD_SIZE) {
553 		unsigned long bmap_size;
554 		unsigned long start;
555 
556 		bmap_size = bootmem_bootmap_pages(end_pfn - start_pfn + 1);
557 		bmap_size = PFN_PHYS(bmap_size);
558 
559 		if (PFN_PHYS(start_pfn) + bmap_size > INITRD_START) {
560 			start = PFN_PHYS(start_pfn) + bmap_size + PAGE_SIZE;
561 
562 			if (start + INITRD_SIZE > memory_end) {
563 				pr_err("initrd extends beyond end of "
564 				       "memory (0x%08lx > 0x%08lx) "
565 				       "disabling initrd\n",
566 				       start + INITRD_SIZE, memory_end);
567 				INITRD_START = INITRD_SIZE = 0;
568 			} else {
569 				pr_info("Moving initrd (0x%08lx -> "
570 					"0x%08lx, size: %ld)\n",
571 					INITRD_START, start, INITRD_SIZE);
572 				memmove((void *) start, (void *) INITRD_START,
573 					INITRD_SIZE);
574 				INITRD_START = start;
575 			}
576 		}
577 	}
578 #endif
579 
580 	/*
581 	 * Initialize the boot-time allocator
582 	 */
583 	bootmap_size = init_bootmem(start_pfn, end_pfn);
584 
585 	/*
586 	 * Register RAM areas with the bootmem allocator.
587 	 */
588 
589 	for (i = 0; i < MEMORY_CHUNKS && memory_chunk[i].size > 0; i++) {
590 		unsigned long start_chunk, end_chunk, pfn;
591 
592 		if (memory_chunk[i].type != CHUNK_READ_WRITE)
593 			continue;
594 		start_chunk = PFN_DOWN(memory_chunk[i].addr);
595 		end_chunk = start_chunk + PFN_DOWN(memory_chunk[i].size);
596 		end_chunk = min(end_chunk, end_pfn);
597 		if (start_chunk >= end_chunk)
598 			continue;
599 		add_active_range(0, start_chunk, end_chunk);
600 		pfn = max(start_chunk, start_pfn);
601 		for (; pfn < end_chunk; pfn++)
602 			page_set_storage_key(PFN_PHYS(pfn),
603 					     PAGE_DEFAULT_KEY, 0);
604 	}
605 
606 	psw_set_key(PAGE_DEFAULT_KEY);
607 
608 	free_bootmem_with_active_regions(0, max_pfn);
609 
610 	/*
611 	 * Reserve memory used for lowcore/command line/kernel image.
612 	 */
613 	reserve_bootmem(0, (unsigned long)_ehead, BOOTMEM_DEFAULT);
614 	reserve_bootmem((unsigned long)_stext,
615 			PFN_PHYS(start_pfn) - (unsigned long)_stext,
616 			BOOTMEM_DEFAULT);
617 	/*
618 	 * Reserve the bootmem bitmap itself as well. We do this in two
619 	 * steps (first step was init_bootmem()) because this catches
620 	 * the (very unlikely) case of us accidentally initializing the
621 	 * bootmem allocator with an invalid RAM area.
622 	 */
623 	reserve_bootmem(start_pfn << PAGE_SHIFT, bootmap_size,
624 			BOOTMEM_DEFAULT);
625 
626 #ifdef CONFIG_BLK_DEV_INITRD
627 	if (INITRD_START && INITRD_SIZE) {
628 		if (INITRD_START + INITRD_SIZE <= memory_end) {
629 			reserve_bootmem(INITRD_START, INITRD_SIZE,
630 					BOOTMEM_DEFAULT);
631 			initrd_start = INITRD_START;
632 			initrd_end = initrd_start + INITRD_SIZE;
633 		} else {
634 			pr_err("initrd extends beyond end of "
635 			       "memory (0x%08lx > 0x%08lx) "
636 			       "disabling initrd\n",
637 			       initrd_start + INITRD_SIZE, memory_end);
638 			initrd_start = initrd_end = 0;
639 		}
640 	}
641 #endif
642 }
643 
644 /*
645  * Setup hardware capabilities.
646  */
647 static void __init setup_hwcaps(void)
648 {
649 	static const int stfl_bits[6] = { 0, 2, 7, 17, 19, 21 };
650 	struct cpuid cpu_id;
651 	int i;
652 
653 	/*
654 	 * The store facility list bits numbers as found in the principles
655 	 * of operation are numbered with bit 1UL<<31 as number 0 to
656 	 * bit 1UL<<0 as number 31.
657 	 *   Bit 0: instructions named N3, "backported" to esa-mode
658 	 *   Bit 2: z/Architecture mode is active
659 	 *   Bit 7: the store-facility-list-extended facility is installed
660 	 *   Bit 17: the message-security assist is installed
661 	 *   Bit 19: the long-displacement facility is installed
662 	 *   Bit 21: the extended-immediate facility is installed
663 	 *   Bit 22: extended-translation facility 3 is installed
664 	 *   Bit 30: extended-translation facility 3 enhancement facility
665 	 * These get translated to:
666 	 *   HWCAP_S390_ESAN3 bit 0, HWCAP_S390_ZARCH bit 1,
667 	 *   HWCAP_S390_STFLE bit 2, HWCAP_S390_MSA bit 3,
668 	 *   HWCAP_S390_LDISP bit 4, HWCAP_S390_EIMM bit 5 and
669 	 *   HWCAP_S390_ETF3EH bit 8 (22 && 30).
670 	 */
671 	for (i = 0; i < 6; i++)
672 		if (test_facility(stfl_bits[i]))
673 			elf_hwcap |= 1UL << i;
674 
675 	if (test_facility(22) && test_facility(30))
676 		elf_hwcap |= HWCAP_S390_ETF3EH;
677 
678 	/*
679 	 * Check for additional facilities with store-facility-list-extended.
680 	 * stfle stores doublewords (8 byte) with bit 1ULL<<63 as bit 0
681 	 * and 1ULL<<0 as bit 63. Bits 0-31 contain the same information
682 	 * as stored by stfl, bits 32-xxx contain additional facilities.
683 	 * How many facility words are stored depends on the number of
684 	 * doublewords passed to the instruction. The additional facilities
685 	 * are:
686 	 *   Bit 42: decimal floating point facility is installed
687 	 *   Bit 44: perform floating point operation facility is installed
688 	 * translated to:
689 	 *   HWCAP_S390_DFP bit 6 (42 && 44).
690 	 */
691 	if ((elf_hwcap & (1UL << 2)) && test_facility(42) && test_facility(44))
692 		elf_hwcap |= HWCAP_S390_DFP;
693 
694 	/*
695 	 * Huge page support HWCAP_S390_HPAGE is bit 7.
696 	 */
697 	if (MACHINE_HAS_HPAGE)
698 		elf_hwcap |= HWCAP_S390_HPAGE;
699 
700 	/*
701 	 * 64-bit register support for 31-bit processes
702 	 * HWCAP_S390_HIGH_GPRS is bit 9.
703 	 */
704 	elf_hwcap |= HWCAP_S390_HIGH_GPRS;
705 
706 	get_cpu_id(&cpu_id);
707 	switch (cpu_id.machine) {
708 	case 0x9672:
709 #if !defined(CONFIG_64BIT)
710 	default:	/* Use "g5" as default for 31 bit kernels. */
711 #endif
712 		strcpy(elf_platform, "g5");
713 		break;
714 	case 0x2064:
715 	case 0x2066:
716 #if defined(CONFIG_64BIT)
717 	default:	/* Use "z900" as default for 64 bit kernels. */
718 #endif
719 		strcpy(elf_platform, "z900");
720 		break;
721 	case 0x2084:
722 	case 0x2086:
723 		strcpy(elf_platform, "z990");
724 		break;
725 	case 0x2094:
726 	case 0x2096:
727 		strcpy(elf_platform, "z9-109");
728 		break;
729 	case 0x2097:
730 	case 0x2098:
731 		strcpy(elf_platform, "z10");
732 		break;
733 	case 0x2817:
734 		strcpy(elf_platform, "z196");
735 		break;
736 	}
737 }
738 
739 /*
740  * Setup function called from init/main.c just after the banner
741  * was printed.
742  */
743 
744 void __init
745 setup_arch(char **cmdline_p)
746 {
747         /*
748          * print what head.S has found out about the machine
749          */
750 #ifndef CONFIG_64BIT
751 	if (MACHINE_IS_VM)
752 		pr_info("Linux is running as a z/VM "
753 			"guest operating system in 31-bit mode\n");
754 	else if (MACHINE_IS_LPAR)
755 		pr_info("Linux is running natively in 31-bit mode\n");
756 	if (MACHINE_HAS_IEEE)
757 		pr_info("The hardware system has IEEE compatible "
758 			"floating point units\n");
759 	else
760 		pr_info("The hardware system has no IEEE compatible "
761 			"floating point units\n");
762 #else /* CONFIG_64BIT */
763 	if (MACHINE_IS_VM)
764 		pr_info("Linux is running as a z/VM "
765 			"guest operating system in 64-bit mode\n");
766 	else if (MACHINE_IS_KVM)
767 		pr_info("Linux is running under KVM in 64-bit mode\n");
768 	else if (MACHINE_IS_LPAR)
769 		pr_info("Linux is running natively in 64-bit mode\n");
770 #endif /* CONFIG_64BIT */
771 
772 	/* Have one command line that is parsed and saved in /proc/cmdline */
773 	/* boot_command_line has been already set up in early.c */
774 	*cmdline_p = boot_command_line;
775 
776         ROOT_DEV = Root_RAM0;
777 
778 	init_mm.start_code = PAGE_OFFSET;
779 	init_mm.end_code = (unsigned long) &_etext;
780 	init_mm.end_data = (unsigned long) &_edata;
781 	init_mm.brk = (unsigned long) &_end;
782 
783 	if (MACHINE_HAS_MVCOS)
784 		memcpy(&uaccess, &uaccess_mvcos, sizeof(uaccess));
785 	else
786 		memcpy(&uaccess, &uaccess_std, sizeof(uaccess));
787 
788 	parse_early_param();
789 
790 	setup_ipl();
791 	setup_memory_end();
792 	setup_addressing_mode();
793 	setup_memory();
794 	setup_resources();
795 	setup_lowcore();
796 
797         cpu_init();
798 	s390_init_cpu_topology();
799 
800 	/*
801 	 * Setup capabilities (ELF_HWCAP & ELF_PLATFORM).
802 	 */
803 	setup_hwcaps();
804 
805 	/*
806 	 * Create kernel page tables and switch to virtual addressing.
807 	 */
808         paging_init();
809 
810         /* Setup default console */
811 	conmode_default();
812 	set_preferred_console();
813 
814 	/* Setup zfcpdump support */
815 	setup_zfcpdump(console_devno);
816 }
817