xref: /openbmc/linux/arch/s390/kernel/setup.c (revision 680ef72a)
1 /*
2  *  S390 version
3  *    Copyright IBM Corp. 1999, 2012
4  *    Author(s): Hartmut Penner (hp@de.ibm.com),
5  *               Martin Schwidefsky (schwidefsky@de.ibm.com)
6  *
7  *  Derived from "arch/i386/kernel/setup.c"
8  *    Copyright (C) 1995, Linus Torvalds
9  */
10 
11 /*
12  * This file handles the architecture-dependent parts of initialization
13  */
14 
15 #define KMSG_COMPONENT "setup"
16 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
17 
18 #include <linux/errno.h>
19 #include <linux/export.h>
20 #include <linux/sched.h>
21 #include <linux/sched/task.h>
22 #include <linux/cpu.h>
23 #include <linux/kernel.h>
24 #include <linux/memblock.h>
25 #include <linux/mm.h>
26 #include <linux/stddef.h>
27 #include <linux/unistd.h>
28 #include <linux/ptrace.h>
29 #include <linux/random.h>
30 #include <linux/user.h>
31 #include <linux/tty.h>
32 #include <linux/ioport.h>
33 #include <linux/delay.h>
34 #include <linux/init.h>
35 #include <linux/initrd.h>
36 #include <linux/bootmem.h>
37 #include <linux/root_dev.h>
38 #include <linux/console.h>
39 #include <linux/kernel_stat.h>
40 #include <linux/dma-contiguous.h>
41 #include <linux/device.h>
42 #include <linux/notifier.h>
43 #include <linux/pfn.h>
44 #include <linux/ctype.h>
45 #include <linux/reboot.h>
46 #include <linux/topology.h>
47 #include <linux/kexec.h>
48 #include <linux/crash_dump.h>
49 #include <linux/memory.h>
50 #include <linux/compat.h>
51 
52 #include <asm/ipl.h>
53 #include <asm/facility.h>
54 #include <asm/smp.h>
55 #include <asm/mmu_context.h>
56 #include <asm/cpcmd.h>
57 #include <asm/lowcore.h>
58 #include <asm/nmi.h>
59 #include <asm/irq.h>
60 #include <asm/page.h>
61 #include <asm/ptrace.h>
62 #include <asm/sections.h>
63 #include <asm/ebcdic.h>
64 #include <asm/diag.h>
65 #include <asm/os_info.h>
66 #include <asm/sclp.h>
67 #include <asm/sysinfo.h>
68 #include <asm/numa.h>
69 #include <asm/alternative.h>
70 #include "entry.h"
71 
72 /*
73  * Machine setup..
74  */
75 unsigned int console_mode = 0;
76 EXPORT_SYMBOL(console_mode);
77 
78 unsigned int console_devno = -1;
79 EXPORT_SYMBOL(console_devno);
80 
81 unsigned int console_irq = -1;
82 EXPORT_SYMBOL(console_irq);
83 
84 unsigned long elf_hwcap __read_mostly = 0;
85 char elf_platform[ELF_PLATFORM_SIZE];
86 
87 unsigned long int_hwcap = 0;
88 
89 int __initdata memory_end_set;
90 unsigned long __initdata memory_end;
91 unsigned long __initdata max_physmem_end;
92 
93 unsigned long VMALLOC_START;
94 EXPORT_SYMBOL(VMALLOC_START);
95 
96 unsigned long VMALLOC_END;
97 EXPORT_SYMBOL(VMALLOC_END);
98 
99 struct page *vmemmap;
100 EXPORT_SYMBOL(vmemmap);
101 
102 unsigned long MODULES_VADDR;
103 unsigned long MODULES_END;
104 
105 /* An array with a pointer to the lowcore of every CPU. */
106 struct lowcore *lowcore_ptr[NR_CPUS];
107 EXPORT_SYMBOL(lowcore_ptr);
108 
109 /*
110  * This is set up by the setup-routine at boot-time
111  * for S390 need to find out, what we have to setup
112  * using address 0x10400 ...
113  */
114 
115 #include <asm/setup.h>
116 
117 /*
118  * condev= and conmode= setup parameter.
119  */
120 
121 static int __init condev_setup(char *str)
122 {
123 	int vdev;
124 
125 	vdev = simple_strtoul(str, &str, 0);
126 	if (vdev >= 0 && vdev < 65536) {
127 		console_devno = vdev;
128 		console_irq = -1;
129 	}
130 	return 1;
131 }
132 
133 __setup("condev=", condev_setup);
134 
135 static void __init set_preferred_console(void)
136 {
137 	if (CONSOLE_IS_3215 || CONSOLE_IS_SCLP)
138 		add_preferred_console("ttyS", 0, NULL);
139 	else if (CONSOLE_IS_3270)
140 		add_preferred_console("tty3270", 0, NULL);
141 	else if (CONSOLE_IS_VT220)
142 		add_preferred_console("ttyS", 1, NULL);
143 	else if (CONSOLE_IS_HVC)
144 		add_preferred_console("hvc", 0, NULL);
145 }
146 
147 static int __init conmode_setup(char *str)
148 {
149 #if defined(CONFIG_SCLP_CONSOLE) || defined(CONFIG_SCLP_VT220_CONSOLE)
150 	if (strncmp(str, "hwc", 4) == 0 || strncmp(str, "sclp", 5) == 0)
151                 SET_CONSOLE_SCLP;
152 #endif
153 #if defined(CONFIG_TN3215_CONSOLE)
154 	if (strncmp(str, "3215", 5) == 0)
155 		SET_CONSOLE_3215;
156 #endif
157 #if defined(CONFIG_TN3270_CONSOLE)
158 	if (strncmp(str, "3270", 5) == 0)
159 		SET_CONSOLE_3270;
160 #endif
161 	set_preferred_console();
162         return 1;
163 }
164 
165 __setup("conmode=", conmode_setup);
166 
167 static void __init conmode_default(void)
168 {
169 	char query_buffer[1024];
170 	char *ptr;
171 
172         if (MACHINE_IS_VM) {
173 		cpcmd("QUERY CONSOLE", query_buffer, 1024, NULL);
174 		console_devno = simple_strtoul(query_buffer + 5, NULL, 16);
175 		ptr = strstr(query_buffer, "SUBCHANNEL =");
176 		console_irq = simple_strtoul(ptr + 13, NULL, 16);
177 		cpcmd("QUERY TERM", query_buffer, 1024, NULL);
178 		ptr = strstr(query_buffer, "CONMODE");
179 		/*
180 		 * Set the conmode to 3215 so that the device recognition
181 		 * will set the cu_type of the console to 3215. If the
182 		 * conmode is 3270 and we don't set it back then both
183 		 * 3215 and the 3270 driver will try to access the console
184 		 * device (3215 as console and 3270 as normal tty).
185 		 */
186 		cpcmd("TERM CONMODE 3215", NULL, 0, NULL);
187 		if (ptr == NULL) {
188 #if defined(CONFIG_SCLP_CONSOLE) || defined(CONFIG_SCLP_VT220_CONSOLE)
189 			SET_CONSOLE_SCLP;
190 #endif
191 			return;
192 		}
193 		if (strncmp(ptr + 8, "3270", 4) == 0) {
194 #if defined(CONFIG_TN3270_CONSOLE)
195 			SET_CONSOLE_3270;
196 #elif defined(CONFIG_TN3215_CONSOLE)
197 			SET_CONSOLE_3215;
198 #elif defined(CONFIG_SCLP_CONSOLE) || defined(CONFIG_SCLP_VT220_CONSOLE)
199 			SET_CONSOLE_SCLP;
200 #endif
201 		} else if (strncmp(ptr + 8, "3215", 4) == 0) {
202 #if defined(CONFIG_TN3215_CONSOLE)
203 			SET_CONSOLE_3215;
204 #elif defined(CONFIG_TN3270_CONSOLE)
205 			SET_CONSOLE_3270;
206 #elif defined(CONFIG_SCLP_CONSOLE) || defined(CONFIG_SCLP_VT220_CONSOLE)
207 			SET_CONSOLE_SCLP;
208 #endif
209 		}
210 	} else if (MACHINE_IS_KVM) {
211 		if (sclp.has_vt220 && IS_ENABLED(CONFIG_SCLP_VT220_CONSOLE))
212 			SET_CONSOLE_VT220;
213 		else if (sclp.has_linemode && IS_ENABLED(CONFIG_SCLP_CONSOLE))
214 			SET_CONSOLE_SCLP;
215 		else
216 			SET_CONSOLE_HVC;
217 	} else {
218 #if defined(CONFIG_SCLP_CONSOLE) || defined(CONFIG_SCLP_VT220_CONSOLE)
219 		SET_CONSOLE_SCLP;
220 #endif
221 	}
222 }
223 
224 #ifdef CONFIG_CRASH_DUMP
225 static void __init setup_zfcpdump(void)
226 {
227 	if (ipl_info.type != IPL_TYPE_FCP_DUMP)
228 		return;
229 	if (OLDMEM_BASE)
230 		return;
231 	strcat(boot_command_line, " cio_ignore=all,!ipldev,!condev");
232 	console_loglevel = 2;
233 }
234 #else
235 static inline void setup_zfcpdump(void) {}
236 #endif /* CONFIG_CRASH_DUMP */
237 
238  /*
239  * Reboot, halt and power_off stubs. They just call _machine_restart,
240  * _machine_halt or _machine_power_off.
241  */
242 
243 void machine_restart(char *command)
244 {
245 	if ((!in_interrupt() && !in_atomic()) || oops_in_progress)
246 		/*
247 		 * Only unblank the console if we are called in enabled
248 		 * context or a bust_spinlocks cleared the way for us.
249 		 */
250 		console_unblank();
251 	_machine_restart(command);
252 }
253 
254 void machine_halt(void)
255 {
256 	if (!in_interrupt() || oops_in_progress)
257 		/*
258 		 * Only unblank the console if we are called in enabled
259 		 * context or a bust_spinlocks cleared the way for us.
260 		 */
261 		console_unblank();
262 	_machine_halt();
263 }
264 
265 void machine_power_off(void)
266 {
267 	if (!in_interrupt() || oops_in_progress)
268 		/*
269 		 * Only unblank the console if we are called in enabled
270 		 * context or a bust_spinlocks cleared the way for us.
271 		 */
272 		console_unblank();
273 	_machine_power_off();
274 }
275 
276 /*
277  * Dummy power off function.
278  */
279 void (*pm_power_off)(void) = machine_power_off;
280 EXPORT_SYMBOL_GPL(pm_power_off);
281 
282 static int __init early_parse_mem(char *p)
283 {
284 	memory_end = memparse(p, &p);
285 	memory_end &= PAGE_MASK;
286 	memory_end_set = 1;
287 	return 0;
288 }
289 early_param("mem", early_parse_mem);
290 
291 static int __init parse_vmalloc(char *arg)
292 {
293 	if (!arg)
294 		return -EINVAL;
295 	VMALLOC_END = (memparse(arg, &arg) + PAGE_SIZE - 1) & PAGE_MASK;
296 	return 0;
297 }
298 early_param("vmalloc", parse_vmalloc);
299 
300 void *restart_stack __section(.data);
301 
302 static void __init setup_lowcore(void)
303 {
304 	struct lowcore *lc;
305 
306 	/*
307 	 * Setup lowcore for boot cpu
308 	 */
309 	BUILD_BUG_ON(sizeof(struct lowcore) != LC_PAGES * PAGE_SIZE);
310 	lc = memblock_virt_alloc_low(sizeof(*lc), sizeof(*lc));
311 	lc->restart_psw.mask = PSW_KERNEL_BITS;
312 	lc->restart_psw.addr = (unsigned long) restart_int_handler;
313 	lc->external_new_psw.mask = PSW_KERNEL_BITS |
314 		PSW_MASK_DAT | PSW_MASK_MCHECK;
315 	lc->external_new_psw.addr = (unsigned long) ext_int_handler;
316 	lc->svc_new_psw.mask = PSW_KERNEL_BITS |
317 		PSW_MASK_DAT | PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK;
318 	lc->svc_new_psw.addr = (unsigned long) system_call;
319 	lc->program_new_psw.mask = PSW_KERNEL_BITS |
320 		PSW_MASK_DAT | PSW_MASK_MCHECK;
321 	lc->program_new_psw.addr = (unsigned long) pgm_check_handler;
322 	lc->mcck_new_psw.mask = PSW_KERNEL_BITS;
323 	lc->mcck_new_psw.addr = (unsigned long) mcck_int_handler;
324 	lc->io_new_psw.mask = PSW_KERNEL_BITS |
325 		PSW_MASK_DAT | PSW_MASK_MCHECK;
326 	lc->io_new_psw.addr = (unsigned long) io_int_handler;
327 	lc->clock_comparator = clock_comparator_max;
328 	lc->kernel_stack = ((unsigned long) &init_thread_union)
329 		+ THREAD_SIZE - STACK_FRAME_OVERHEAD - sizeof(struct pt_regs);
330 	lc->async_stack = (unsigned long)
331 		memblock_virt_alloc(ASYNC_SIZE, ASYNC_SIZE)
332 		+ ASYNC_SIZE - STACK_FRAME_OVERHEAD - sizeof(struct pt_regs);
333 	lc->panic_stack = (unsigned long)
334 		memblock_virt_alloc(PAGE_SIZE, PAGE_SIZE)
335 		+ PAGE_SIZE - STACK_FRAME_OVERHEAD - sizeof(struct pt_regs);
336 	lc->current_task = (unsigned long)&init_task;
337 	lc->lpp = LPP_MAGIC;
338 	lc->machine_flags = S390_lowcore.machine_flags;
339 	lc->preempt_count = S390_lowcore.preempt_count;
340 	lc->stfl_fac_list = S390_lowcore.stfl_fac_list;
341 	memcpy(lc->stfle_fac_list, S390_lowcore.stfle_fac_list,
342 	       MAX_FACILITY_BIT/8);
343 	nmi_alloc_boot_cpu(lc);
344 	vdso_alloc_boot_cpu(lc);
345 	lc->sync_enter_timer = S390_lowcore.sync_enter_timer;
346 	lc->async_enter_timer = S390_lowcore.async_enter_timer;
347 	lc->exit_timer = S390_lowcore.exit_timer;
348 	lc->user_timer = S390_lowcore.user_timer;
349 	lc->system_timer = S390_lowcore.system_timer;
350 	lc->steal_timer = S390_lowcore.steal_timer;
351 	lc->last_update_timer = S390_lowcore.last_update_timer;
352 	lc->last_update_clock = S390_lowcore.last_update_clock;
353 
354 	restart_stack = memblock_virt_alloc(ASYNC_SIZE, ASYNC_SIZE);
355 	restart_stack += ASYNC_SIZE;
356 
357 	/*
358 	 * Set up PSW restart to call ipl.c:do_restart(). Copy the relevant
359 	 * restart data to the absolute zero lowcore. This is necessary if
360 	 * PSW restart is done on an offline CPU that has lowcore zero.
361 	 */
362 	lc->restart_stack = (unsigned long) restart_stack;
363 	lc->restart_fn = (unsigned long) do_restart;
364 	lc->restart_data = 0;
365 	lc->restart_source = -1UL;
366 
367 	/* Setup absolute zero lowcore */
368 	mem_assign_absolute(S390_lowcore.restart_stack, lc->restart_stack);
369 	mem_assign_absolute(S390_lowcore.restart_fn, lc->restart_fn);
370 	mem_assign_absolute(S390_lowcore.restart_data, lc->restart_data);
371 	mem_assign_absolute(S390_lowcore.restart_source, lc->restart_source);
372 	mem_assign_absolute(S390_lowcore.restart_psw, lc->restart_psw);
373 
374 #ifdef CONFIG_SMP
375 	lc->spinlock_lockval = arch_spin_lockval(0);
376 	lc->spinlock_index = 0;
377 	arch_spin_lock_setup(0);
378 #endif
379 
380 	set_prefix((u32)(unsigned long) lc);
381 	lowcore_ptr[0] = lc;
382 }
383 
384 static struct resource code_resource = {
385 	.name  = "Kernel code",
386 	.flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM,
387 };
388 
389 static struct resource data_resource = {
390 	.name = "Kernel data",
391 	.flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM,
392 };
393 
394 static struct resource bss_resource = {
395 	.name = "Kernel bss",
396 	.flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM,
397 };
398 
399 static struct resource __initdata *standard_resources[] = {
400 	&code_resource,
401 	&data_resource,
402 	&bss_resource,
403 };
404 
405 static void __init setup_resources(void)
406 {
407 	struct resource *res, *std_res, *sub_res;
408 	struct memblock_region *reg;
409 	int j;
410 
411 	code_resource.start = (unsigned long) &_text;
412 	code_resource.end = (unsigned long) &_etext - 1;
413 	data_resource.start = (unsigned long) &_etext;
414 	data_resource.end = (unsigned long) &_edata - 1;
415 	bss_resource.start = (unsigned long) &__bss_start;
416 	bss_resource.end = (unsigned long) &__bss_stop - 1;
417 
418 	for_each_memblock(memory, reg) {
419 		res = memblock_virt_alloc(sizeof(*res), 8);
420 		res->flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM;
421 
422 		res->name = "System RAM";
423 		res->start = reg->base;
424 		res->end = reg->base + reg->size - 1;
425 		request_resource(&iomem_resource, res);
426 
427 		for (j = 0; j < ARRAY_SIZE(standard_resources); j++) {
428 			std_res = standard_resources[j];
429 			if (std_res->start < res->start ||
430 			    std_res->start > res->end)
431 				continue;
432 			if (std_res->end > res->end) {
433 				sub_res = memblock_virt_alloc(sizeof(*sub_res), 8);
434 				*sub_res = *std_res;
435 				sub_res->end = res->end;
436 				std_res->start = res->end + 1;
437 				request_resource(res, sub_res);
438 			} else {
439 				request_resource(res, std_res);
440 			}
441 		}
442 	}
443 #ifdef CONFIG_CRASH_DUMP
444 	/*
445 	 * Re-add removed crash kernel memory as reserved memory. This makes
446 	 * sure it will be mapped with the identity mapping and struct pages
447 	 * will be created, so it can be resized later on.
448 	 * However add it later since the crash kernel resource should not be
449 	 * part of the System RAM resource.
450 	 */
451 	if (crashk_res.end) {
452 		memblock_add_node(crashk_res.start, resource_size(&crashk_res), 0);
453 		memblock_reserve(crashk_res.start, resource_size(&crashk_res));
454 		insert_resource(&iomem_resource, &crashk_res);
455 	}
456 #endif
457 }
458 
459 static void __init setup_memory_end(void)
460 {
461 	unsigned long vmax, vmalloc_size, tmp;
462 
463 	/* Choose kernel address space layout: 2, 3, or 4 levels. */
464 	vmalloc_size = VMALLOC_END ?: (128UL << 30) - MODULES_LEN;
465 	tmp = (memory_end ?: max_physmem_end) / PAGE_SIZE;
466 	tmp = tmp * (sizeof(struct page) + PAGE_SIZE);
467 	if (tmp + vmalloc_size + MODULES_LEN <= _REGION2_SIZE)
468 		vmax = _REGION2_SIZE; /* 3-level kernel page table */
469 	else
470 		vmax = _REGION1_SIZE; /* 4-level kernel page table */
471 	/* module area is at the end of the kernel address space. */
472 	MODULES_END = vmax;
473 	MODULES_VADDR = MODULES_END - MODULES_LEN;
474 	VMALLOC_END = MODULES_VADDR;
475 	VMALLOC_START = vmax - vmalloc_size;
476 
477 	/* Split remaining virtual space between 1:1 mapping & vmemmap array */
478 	tmp = VMALLOC_START / (PAGE_SIZE + sizeof(struct page));
479 	/* vmemmap contains a multiple of PAGES_PER_SECTION struct pages */
480 	tmp = SECTION_ALIGN_UP(tmp);
481 	tmp = VMALLOC_START - tmp * sizeof(struct page);
482 	tmp &= ~((vmax >> 11) - 1);	/* align to page table level */
483 	tmp = min(tmp, 1UL << MAX_PHYSMEM_BITS);
484 	vmemmap = (struct page *) tmp;
485 
486 	/* Take care that memory_end is set and <= vmemmap */
487 	memory_end = min(memory_end ?: max_physmem_end, tmp);
488 	max_pfn = max_low_pfn = PFN_DOWN(memory_end);
489 	memblock_remove(memory_end, ULONG_MAX);
490 
491 	pr_notice("The maximum memory size is %luMB\n", memory_end >> 20);
492 }
493 
494 #ifdef CONFIG_CRASH_DUMP
495 
496 /*
497  * When kdump is enabled, we have to ensure that no memory from
498  * the area [0 - crashkernel memory size] and
499  * [crashk_res.start - crashk_res.end] is set offline.
500  */
501 static int kdump_mem_notifier(struct notifier_block *nb,
502 			      unsigned long action, void *data)
503 {
504 	struct memory_notify *arg = data;
505 
506 	if (action != MEM_GOING_OFFLINE)
507 		return NOTIFY_OK;
508 	if (arg->start_pfn < PFN_DOWN(resource_size(&crashk_res)))
509 		return NOTIFY_BAD;
510 	if (arg->start_pfn > PFN_DOWN(crashk_res.end))
511 		return NOTIFY_OK;
512 	if (arg->start_pfn + arg->nr_pages - 1 < PFN_DOWN(crashk_res.start))
513 		return NOTIFY_OK;
514 	return NOTIFY_BAD;
515 }
516 
517 static struct notifier_block kdump_mem_nb = {
518 	.notifier_call = kdump_mem_notifier,
519 };
520 
521 #endif
522 
523 /*
524  * Make sure that the area behind memory_end is protected
525  */
526 static void reserve_memory_end(void)
527 {
528 #ifdef CONFIG_CRASH_DUMP
529 	if (ipl_info.type == IPL_TYPE_FCP_DUMP &&
530 	    !OLDMEM_BASE && sclp.hsa_size) {
531 		memory_end = sclp.hsa_size;
532 		memory_end &= PAGE_MASK;
533 		memory_end_set = 1;
534 	}
535 #endif
536 	if (!memory_end_set)
537 		return;
538 	memblock_reserve(memory_end, ULONG_MAX);
539 }
540 
541 /*
542  * Make sure that oldmem, where the dump is stored, is protected
543  */
544 static void reserve_oldmem(void)
545 {
546 #ifdef CONFIG_CRASH_DUMP
547 	if (OLDMEM_BASE)
548 		/* Forget all memory above the running kdump system */
549 		memblock_reserve(OLDMEM_SIZE, (phys_addr_t)ULONG_MAX);
550 #endif
551 }
552 
553 /*
554  * Make sure that oldmem, where the dump is stored, is protected
555  */
556 static void remove_oldmem(void)
557 {
558 #ifdef CONFIG_CRASH_DUMP
559 	if (OLDMEM_BASE)
560 		/* Forget all memory above the running kdump system */
561 		memblock_remove(OLDMEM_SIZE, (phys_addr_t)ULONG_MAX);
562 #endif
563 }
564 
565 /*
566  * Reserve memory for kdump kernel to be loaded with kexec
567  */
568 static void __init reserve_crashkernel(void)
569 {
570 #ifdef CONFIG_CRASH_DUMP
571 	unsigned long long crash_base, crash_size;
572 	phys_addr_t low, high;
573 	int rc;
574 
575 	rc = parse_crashkernel(boot_command_line, memory_end, &crash_size,
576 			       &crash_base);
577 
578 	crash_base = ALIGN(crash_base, KEXEC_CRASH_MEM_ALIGN);
579 	crash_size = ALIGN(crash_size, KEXEC_CRASH_MEM_ALIGN);
580 	if (rc || crash_size == 0)
581 		return;
582 
583 	if (memblock.memory.regions[0].size < crash_size) {
584 		pr_info("crashkernel reservation failed: %s\n",
585 			"first memory chunk must be at least crashkernel size");
586 		return;
587 	}
588 
589 	low = crash_base ?: OLDMEM_BASE;
590 	high = low + crash_size;
591 	if (low >= OLDMEM_BASE && high <= OLDMEM_BASE + OLDMEM_SIZE) {
592 		/* The crashkernel fits into OLDMEM, reuse OLDMEM */
593 		crash_base = low;
594 	} else {
595 		/* Find suitable area in free memory */
596 		low = max_t(unsigned long, crash_size, sclp.hsa_size);
597 		high = crash_base ? crash_base + crash_size : ULONG_MAX;
598 
599 		if (crash_base && crash_base < low) {
600 			pr_info("crashkernel reservation failed: %s\n",
601 				"crash_base too low");
602 			return;
603 		}
604 		low = crash_base ?: low;
605 		crash_base = memblock_find_in_range(low, high, crash_size,
606 						    KEXEC_CRASH_MEM_ALIGN);
607 	}
608 
609 	if (!crash_base) {
610 		pr_info("crashkernel reservation failed: %s\n",
611 			"no suitable area found");
612 		return;
613 	}
614 
615 	if (register_memory_notifier(&kdump_mem_nb))
616 		return;
617 
618 	if (!OLDMEM_BASE && MACHINE_IS_VM)
619 		diag10_range(PFN_DOWN(crash_base), PFN_DOWN(crash_size));
620 	crashk_res.start = crash_base;
621 	crashk_res.end = crash_base + crash_size - 1;
622 	memblock_remove(crash_base, crash_size);
623 	pr_info("Reserving %lluMB of memory at %lluMB "
624 		"for crashkernel (System RAM: %luMB)\n",
625 		crash_size >> 20, crash_base >> 20,
626 		(unsigned long)memblock.memory.total_size >> 20);
627 	os_info_crashkernel_add(crash_base, crash_size);
628 #endif
629 }
630 
631 /*
632  * Reserve the initrd from being used by memblock
633  */
634 static void __init reserve_initrd(void)
635 {
636 #ifdef CONFIG_BLK_DEV_INITRD
637 	if (!INITRD_START || !INITRD_SIZE)
638 		return;
639 	initrd_start = INITRD_START;
640 	initrd_end = initrd_start + INITRD_SIZE;
641 	memblock_reserve(INITRD_START, INITRD_SIZE);
642 #endif
643 }
644 
645 /*
646  * Check for initrd being in usable memory
647  */
648 static void __init check_initrd(void)
649 {
650 #ifdef CONFIG_BLK_DEV_INITRD
651 	if (INITRD_START && INITRD_SIZE &&
652 	    !memblock_is_region_memory(INITRD_START, INITRD_SIZE)) {
653 		pr_err("The initial RAM disk does not fit into the memory\n");
654 		memblock_free(INITRD_START, INITRD_SIZE);
655 		initrd_start = initrd_end = 0;
656 	}
657 #endif
658 }
659 
660 /*
661  * Reserve memory used for lowcore/command line/kernel image.
662  */
663 static void __init reserve_kernel(void)
664 {
665 	unsigned long start_pfn = PFN_UP(__pa(&_end));
666 
667 #ifdef CONFIG_DMA_API_DEBUG
668 	/*
669 	 * DMA_API_DEBUG code stumbles over addresses from the
670 	 * range [_ehead, _stext]. Mark the memory as reserved
671 	 * so it is not used for CONFIG_DMA_API_DEBUG=y.
672 	 */
673 	memblock_reserve(0, PFN_PHYS(start_pfn));
674 #else
675 	memblock_reserve(0, (unsigned long)_ehead);
676 	memblock_reserve((unsigned long)_stext, PFN_PHYS(start_pfn)
677 			 - (unsigned long)_stext);
678 #endif
679 }
680 
681 static void __init setup_memory(void)
682 {
683 	struct memblock_region *reg;
684 
685 	/*
686 	 * Init storage key for present memory
687 	 */
688 	for_each_memblock(memory, reg) {
689 		storage_key_init_range(reg->base, reg->base + reg->size);
690 	}
691 	psw_set_key(PAGE_DEFAULT_KEY);
692 
693 	/* Only cosmetics */
694 	memblock_enforce_memory_limit(memblock_end_of_DRAM());
695 }
696 
697 /*
698  * Setup hardware capabilities.
699  */
700 static int __init setup_hwcaps(void)
701 {
702 	static const int stfl_bits[6] = { 0, 2, 7, 17, 19, 21 };
703 	struct cpuid cpu_id;
704 	int i;
705 
706 	/*
707 	 * The store facility list bits numbers as found in the principles
708 	 * of operation are numbered with bit 1UL<<31 as number 0 to
709 	 * bit 1UL<<0 as number 31.
710 	 *   Bit 0: instructions named N3, "backported" to esa-mode
711 	 *   Bit 2: z/Architecture mode is active
712 	 *   Bit 7: the store-facility-list-extended facility is installed
713 	 *   Bit 17: the message-security assist is installed
714 	 *   Bit 19: the long-displacement facility is installed
715 	 *   Bit 21: the extended-immediate facility is installed
716 	 *   Bit 22: extended-translation facility 3 is installed
717 	 *   Bit 30: extended-translation facility 3 enhancement facility
718 	 * These get translated to:
719 	 *   HWCAP_S390_ESAN3 bit 0, HWCAP_S390_ZARCH bit 1,
720 	 *   HWCAP_S390_STFLE bit 2, HWCAP_S390_MSA bit 3,
721 	 *   HWCAP_S390_LDISP bit 4, HWCAP_S390_EIMM bit 5 and
722 	 *   HWCAP_S390_ETF3EH bit 8 (22 && 30).
723 	 */
724 	for (i = 0; i < 6; i++)
725 		if (test_facility(stfl_bits[i]))
726 			elf_hwcap |= 1UL << i;
727 
728 	if (test_facility(22) && test_facility(30))
729 		elf_hwcap |= HWCAP_S390_ETF3EH;
730 
731 	/*
732 	 * Check for additional facilities with store-facility-list-extended.
733 	 * stfle stores doublewords (8 byte) with bit 1ULL<<63 as bit 0
734 	 * and 1ULL<<0 as bit 63. Bits 0-31 contain the same information
735 	 * as stored by stfl, bits 32-xxx contain additional facilities.
736 	 * How many facility words are stored depends on the number of
737 	 * doublewords passed to the instruction. The additional facilities
738 	 * are:
739 	 *   Bit 42: decimal floating point facility is installed
740 	 *   Bit 44: perform floating point operation facility is installed
741 	 * translated to:
742 	 *   HWCAP_S390_DFP bit 6 (42 && 44).
743 	 */
744 	if ((elf_hwcap & (1UL << 2)) && test_facility(42) && test_facility(44))
745 		elf_hwcap |= HWCAP_S390_DFP;
746 
747 	/*
748 	 * Huge page support HWCAP_S390_HPAGE is bit 7.
749 	 */
750 	if (MACHINE_HAS_EDAT1)
751 		elf_hwcap |= HWCAP_S390_HPAGE;
752 
753 	/*
754 	 * 64-bit register support for 31-bit processes
755 	 * HWCAP_S390_HIGH_GPRS is bit 9.
756 	 */
757 	elf_hwcap |= HWCAP_S390_HIGH_GPRS;
758 
759 	/*
760 	 * Transactional execution support HWCAP_S390_TE is bit 10.
761 	 */
762 	if (MACHINE_HAS_TE)
763 		elf_hwcap |= HWCAP_S390_TE;
764 
765 	/*
766 	 * Vector extension HWCAP_S390_VXRS is bit 11. The Vector extension
767 	 * can be disabled with the "novx" parameter. Use MACHINE_HAS_VX
768 	 * instead of facility bit 129.
769 	 */
770 	if (MACHINE_HAS_VX) {
771 		elf_hwcap |= HWCAP_S390_VXRS;
772 		if (test_facility(134))
773 			elf_hwcap |= HWCAP_S390_VXRS_EXT;
774 		if (test_facility(135))
775 			elf_hwcap |= HWCAP_S390_VXRS_BCD;
776 	}
777 
778 	/*
779 	 * Guarded storage support HWCAP_S390_GS is bit 12.
780 	 */
781 	if (MACHINE_HAS_GS)
782 		elf_hwcap |= HWCAP_S390_GS;
783 
784 	get_cpu_id(&cpu_id);
785 	add_device_randomness(&cpu_id, sizeof(cpu_id));
786 	switch (cpu_id.machine) {
787 	case 0x2064:
788 	case 0x2066:
789 	default:	/* Use "z900" as default for 64 bit kernels. */
790 		strcpy(elf_platform, "z900");
791 		break;
792 	case 0x2084:
793 	case 0x2086:
794 		strcpy(elf_platform, "z990");
795 		break;
796 	case 0x2094:
797 	case 0x2096:
798 		strcpy(elf_platform, "z9-109");
799 		break;
800 	case 0x2097:
801 	case 0x2098:
802 		strcpy(elf_platform, "z10");
803 		break;
804 	case 0x2817:
805 	case 0x2818:
806 		strcpy(elf_platform, "z196");
807 		break;
808 	case 0x2827:
809 	case 0x2828:
810 		strcpy(elf_platform, "zEC12");
811 		break;
812 	case 0x2964:
813 	case 0x2965:
814 		strcpy(elf_platform, "z13");
815 		break;
816 	case 0x3906:
817 		strcpy(elf_platform, "z14");
818 		break;
819 	}
820 
821 	/*
822 	 * Virtualization support HWCAP_INT_SIE is bit 0.
823 	 */
824 	if (sclp.has_sief2)
825 		int_hwcap |= HWCAP_INT_SIE;
826 
827 	return 0;
828 }
829 arch_initcall(setup_hwcaps);
830 
831 /*
832  * Add system information as device randomness
833  */
834 static void __init setup_randomness(void)
835 {
836 	struct sysinfo_3_2_2 *vmms;
837 
838 	vmms = (struct sysinfo_3_2_2 *) memblock_alloc(PAGE_SIZE, PAGE_SIZE);
839 	if (stsi(vmms, 3, 2, 2) == 0 && vmms->count)
840 		add_device_randomness(&vmms->vm, sizeof(vmms->vm[0]) * vmms->count);
841 	memblock_free((unsigned long) vmms, PAGE_SIZE);
842 }
843 
844 /*
845  * Find the correct size for the task_struct. This depends on
846  * the size of the struct fpu at the end of the thread_struct
847  * which is embedded in the task_struct.
848  */
849 static void __init setup_task_size(void)
850 {
851 	int task_size = sizeof(struct task_struct);
852 
853 	if (!MACHINE_HAS_VX) {
854 		task_size -= sizeof(__vector128) * __NUM_VXRS;
855 		task_size += sizeof(freg_t) * __NUM_FPRS;
856 	}
857 	arch_task_struct_size = task_size;
858 }
859 
860 /*
861  * Setup function called from init/main.c just after the banner
862  * was printed.
863  */
864 
865 void __init setup_arch(char **cmdline_p)
866 {
867         /*
868          * print what head.S has found out about the machine
869          */
870 	if (MACHINE_IS_VM)
871 		pr_info("Linux is running as a z/VM "
872 			"guest operating system in 64-bit mode\n");
873 	else if (MACHINE_IS_KVM)
874 		pr_info("Linux is running under KVM in 64-bit mode\n");
875 	else if (MACHINE_IS_LPAR)
876 		pr_info("Linux is running natively in 64-bit mode\n");
877 
878 	/* Have one command line that is parsed and saved in /proc/cmdline */
879 	/* boot_command_line has been already set up in early.c */
880 	*cmdline_p = boot_command_line;
881 
882         ROOT_DEV = Root_RAM0;
883 
884 	/* Is init_mm really needed? */
885 	init_mm.start_code = PAGE_OFFSET;
886 	init_mm.end_code = (unsigned long) &_etext;
887 	init_mm.end_data = (unsigned long) &_edata;
888 	init_mm.brk = (unsigned long) &_end;
889 
890 	parse_early_param();
891 #ifdef CONFIG_CRASH_DUMP
892 	/* Deactivate elfcorehdr= kernel parameter */
893 	elfcorehdr_addr = ELFCORE_ADDR_MAX;
894 #endif
895 
896 	os_info_init();
897 	setup_ipl();
898 	setup_task_size();
899 
900 	/* Do some memory reservations *before* memory is added to memblock */
901 	reserve_memory_end();
902 	reserve_oldmem();
903 	reserve_kernel();
904 	reserve_initrd();
905 	memblock_allow_resize();
906 
907 	/* Get information about *all* installed memory */
908 	detect_memory_memblock();
909 
910 	remove_oldmem();
911 
912 	/*
913 	 * Make sure all chunks are MAX_ORDER aligned so we don't need the
914 	 * extra checks that HOLES_IN_ZONE would require.
915 	 *
916 	 * Is this still required?
917 	 */
918 	memblock_trim_memory(1UL << (MAX_ORDER - 1 + PAGE_SHIFT));
919 
920 	setup_memory_end();
921 	setup_memory();
922 	dma_contiguous_reserve(memory_end);
923 	vmcp_cma_reserve();
924 
925 	check_initrd();
926 	reserve_crashkernel();
927 #ifdef CONFIG_CRASH_DUMP
928 	/*
929 	 * Be aware that smp_save_dump_cpus() triggers a system reset.
930 	 * Therefore CPU and device initialization should be done afterwards.
931 	 */
932 	smp_save_dump_cpus();
933 #endif
934 
935 	setup_resources();
936 	setup_lowcore();
937 	smp_fill_possible_mask();
938 	cpu_detect_mhz_feature();
939         cpu_init();
940 	numa_setup();
941 	smp_detect_cpus();
942 	topology_init_early();
943 
944 	/*
945 	 * Create kernel page tables and switch to virtual addressing.
946 	 */
947         paging_init();
948 
949         /* Setup default console */
950 	conmode_default();
951 	set_preferred_console();
952 
953 	apply_alternative_instructions();
954 
955 	/* Setup zfcpdump support */
956 	setup_zfcpdump();
957 
958 	/* Add system specific data to the random pool */
959 	setup_randomness();
960 }
961