xref: /linux/arch/mips/kernel/setup.c (revision a9e1a3d84e4a0ea560ed4d84c28d06dbfdffed22)
1 /*
2  * This file is subject to the terms and conditions of the GNU General Public
3  * License.  See the file "COPYING" in the main directory of this archive
4  * for more details.
5  *
6  * Copyright (C) 1995 Linus Torvalds
7  * Copyright (C) 1995 Waldorf Electronics
8  * Copyright (C) 1994, 95, 96, 97, 98, 99, 2000, 01, 02, 03  Ralf Baechle
9  * Copyright (C) 1996 Stoned Elipot
10  * Copyright (C) 1999 Silicon Graphics, Inc.
11  * Copyright (C) 2000, 2001, 2002, 2007	 Maciej W. Rozycki
12  */
13 #include <linux/init.h>
14 #include <linux/cpu.h>
15 #include <linux/delay.h>
16 #include <linux/ioport.h>
17 #include <linux/export.h>
18 #include <linux/screen_info.h>
19 #include <linux/memblock.h>
20 #include <linux/initrd.h>
21 #include <linux/root_dev.h>
22 #include <linux/highmem.h>
23 #include <linux/console.h>
24 #include <linux/pfn.h>
25 #include <linux/debugfs.h>
26 #include <linux/kexec.h>
27 #include <linux/sizes.h>
28 #include <linux/device.h>
29 #include <linux/dma-map-ops.h>
30 #include <linux/decompress/generic.h>
31 #include <linux/of_fdt.h>
32 #include <linux/dmi.h>
33 #include <linux/crash_dump.h>
34 
35 #include <asm/addrspace.h>
36 #include <asm/bootinfo.h>
37 #include <asm/bugs.h>
38 #include <asm/cache.h>
39 #include <asm/cdmm.h>
40 #include <asm/cpu.h>
41 #include <asm/debug.h>
42 #include <asm/mmzone.h>
43 #include <asm/sections.h>
44 #include <asm/setup.h>
45 #include <asm/smp-ops.h>
46 #include <asm/prom.h>
47 #include <asm/fw/fw.h>
48 
49 #ifdef CONFIG_MIPS_ELF_APPENDED_DTB
50 char __section(".appended_dtb") __appended_dtb[0x100000];
51 #endif /* CONFIG_MIPS_ELF_APPENDED_DTB */
52 
53 struct cpuinfo_mips cpu_data[NR_CPUS] __read_mostly;
54 
55 EXPORT_SYMBOL(cpu_data);
56 
57 #ifdef CONFIG_VT
58 struct screen_info screen_info;
59 #endif
60 
61 /*
62  * Setup information
63  *
64  * These are initialized so they are in the .data section
65  */
66 unsigned long mips_machtype __read_mostly = MACH_UNKNOWN;
67 
68 EXPORT_SYMBOL(mips_machtype);
69 
70 static char __initdata command_line[COMMAND_LINE_SIZE];
71 char __initdata arcs_cmdline[COMMAND_LINE_SIZE];
72 
73 #ifdef CONFIG_CMDLINE_BOOL
74 static const char builtin_cmdline[] __initconst = CONFIG_CMDLINE;
75 #else
76 static const char builtin_cmdline[] __initconst = "";
77 #endif
78 
79 /*
80  * mips_io_port_base is the begin of the address space to which x86 style
81  * I/O ports are mapped.
82  */
83 unsigned long mips_io_port_base = -1;
84 EXPORT_SYMBOL(mips_io_port_base);
85 
86 static struct resource code_resource = { .name = "Kernel code", };
87 static struct resource data_resource = { .name = "Kernel data", };
88 static struct resource bss_resource = { .name = "Kernel bss", };
89 
90 unsigned long __kaslr_offset __ro_after_init;
91 EXPORT_SYMBOL(__kaslr_offset);
92 
93 static void *detect_magic __initdata = detect_memory_region;
94 
95 #ifdef CONFIG_MIPS_AUTO_PFN_OFFSET
96 unsigned long ARCH_PFN_OFFSET;
97 EXPORT_SYMBOL(ARCH_PFN_OFFSET);
98 #endif
99 
100 void __init detect_memory_region(phys_addr_t start, phys_addr_t sz_min, phys_addr_t sz_max)
101 {
102 	void *dm = &detect_magic;
103 	phys_addr_t size;
104 
105 	for (size = sz_min; size < sz_max; size <<= 1) {
106 		if (!memcmp(dm, dm + size, sizeof(detect_magic)))
107 			break;
108 	}
109 
110 	pr_debug("Memory: %lluMB of RAM detected at 0x%llx (min: %lluMB, max: %lluMB)\n",
111 		((unsigned long long) size) / SZ_1M,
112 		(unsigned long long) start,
113 		((unsigned long long) sz_min) / SZ_1M,
114 		((unsigned long long) sz_max) / SZ_1M);
115 
116 	memblock_add(start, size);
117 }
118 
119 /*
120  * Manage initrd
121  */
122 #ifdef CONFIG_BLK_DEV_INITRD
123 
124 static int __init rd_start_early(char *p)
125 {
126 	unsigned long start = memparse(p, &p);
127 
128 #ifdef CONFIG_64BIT
129 	/* Guess if the sign extension was forgotten by bootloader */
130 	if (start < XKPHYS)
131 		start = (int)start;
132 #endif
133 	initrd_start = start;
134 	initrd_end += start;
135 	return 0;
136 }
137 early_param("rd_start", rd_start_early);
138 
139 static int __init rd_size_early(char *p)
140 {
141 	initrd_end += memparse(p, &p);
142 	return 0;
143 }
144 early_param("rd_size", rd_size_early);
145 
146 /* it returns the next free pfn after initrd */
147 static unsigned long __init init_initrd(void)
148 {
149 	unsigned long end;
150 
151 	/*
152 	 * Board specific code or command line parser should have
153 	 * already set up initrd_start and initrd_end. In these cases
154 	 * perfom sanity checks and use them if all looks good.
155 	 */
156 	if (!initrd_start || initrd_end <= initrd_start)
157 		goto disable;
158 
159 	if (initrd_start & ~PAGE_MASK) {
160 		pr_err("initrd start must be page aligned\n");
161 		goto disable;
162 	}
163 
164 	/*
165 	 * Sanitize initrd addresses. For example firmware
166 	 * can't guess if they need to pass them through
167 	 * 64-bits values if the kernel has been built in pure
168 	 * 32-bit. We need also to switch from KSEG0 to XKPHYS
169 	 * addresses now, so the code can now safely use __pa().
170 	 */
171 	end = __pa(initrd_end);
172 	initrd_end = (unsigned long)__va(end);
173 	initrd_start = (unsigned long)__va(__pa(initrd_start));
174 
175 	if (initrd_start < PAGE_OFFSET) {
176 		pr_err("initrd start < PAGE_OFFSET\n");
177 		goto disable;
178 	}
179 
180 	ROOT_DEV = Root_RAM0;
181 	return PFN_UP(end);
182 disable:
183 	initrd_start = 0;
184 	initrd_end = 0;
185 	return 0;
186 }
187 
188 /* In some conditions (e.g. big endian bootloader with a little endian
189    kernel), the initrd might appear byte swapped.  Try to detect this and
190    byte swap it if needed.  */
191 static void __init maybe_bswap_initrd(void)
192 {
193 #if defined(CONFIG_CPU_CAVIUM_OCTEON)
194 	u64 buf;
195 
196 	/* Check for CPIO signature */
197 	if (!memcmp((void *)initrd_start, "070701", 6))
198 		return;
199 
200 	/* Check for compressed initrd */
201 	if (decompress_method((unsigned char *)initrd_start, 8, NULL))
202 		return;
203 
204 	/* Try again with a byte swapped header */
205 	buf = swab64p((u64 *)initrd_start);
206 	if (!memcmp(&buf, "070701", 6) ||
207 	    decompress_method((unsigned char *)(&buf), 8, NULL)) {
208 		unsigned long i;
209 
210 		pr_info("Byteswapped initrd detected\n");
211 		for (i = initrd_start; i < ALIGN(initrd_end, 8); i += 8)
212 			swab64s((u64 *)i);
213 	}
214 #endif
215 }
216 
217 static void __init finalize_initrd(void)
218 {
219 	unsigned long size = initrd_end - initrd_start;
220 
221 	if (size == 0) {
222 		printk(KERN_INFO "Initrd not found or empty");
223 		goto disable;
224 	}
225 	if (__pa(initrd_end) > PFN_PHYS(max_low_pfn)) {
226 		printk(KERN_ERR "Initrd extends beyond end of memory");
227 		goto disable;
228 	}
229 
230 	maybe_bswap_initrd();
231 
232 	memblock_reserve(__pa(initrd_start), size);
233 	initrd_below_start_ok = 1;
234 
235 	pr_info("Initial ramdisk at: 0x%lx (%lu bytes)\n",
236 		initrd_start, size);
237 	return;
238 disable:
239 	printk(KERN_CONT " - disabling initrd\n");
240 	initrd_start = 0;
241 	initrd_end = 0;
242 }
243 
244 #else  /* !CONFIG_BLK_DEV_INITRD */
245 
246 static unsigned long __init init_initrd(void)
247 {
248 	return 0;
249 }
250 
251 #define finalize_initrd()	do {} while (0)
252 
253 #endif
254 
255 /*
256  * Initialize the bootmem allocator. It also setup initrd related data
257  * if needed.
258  */
259 #if defined(CONFIG_SGI_IP27) || (defined(CONFIG_CPU_LOONGSON64) && defined(CONFIG_NUMA))
260 
261 static void __init bootmem_init(void)
262 {
263 	init_initrd();
264 	finalize_initrd();
265 }
266 
267 #else  /* !CONFIG_SGI_IP27 */
268 
269 static void __init bootmem_init(void)
270 {
271 	phys_addr_t ramstart, ramend;
272 	unsigned long start, end;
273 	int i;
274 
275 	ramstart = memblock_start_of_DRAM();
276 	ramend = memblock_end_of_DRAM();
277 
278 	/*
279 	 * Sanity check any INITRD first. We don't take it into account
280 	 * for bootmem setup initially, rely on the end-of-kernel-code
281 	 * as our memory range starting point. Once bootmem is inited we
282 	 * will reserve the area used for the initrd.
283 	 */
284 	init_initrd();
285 
286 	/* Reserve memory occupied by kernel. */
287 	memblock_reserve(__pa_symbol(&_text),
288 			__pa_symbol(&_end) - __pa_symbol(&_text));
289 
290 	/* max_low_pfn is not a number of pages but the end pfn of low mem */
291 
292 #ifdef CONFIG_MIPS_AUTO_PFN_OFFSET
293 	ARCH_PFN_OFFSET = PFN_UP(ramstart);
294 #else
295 	/*
296 	 * Reserve any memory between the start of RAM and PHYS_OFFSET
297 	 */
298 	if (ramstart > PHYS_OFFSET)
299 		memblock_reserve(PHYS_OFFSET, ramstart - PHYS_OFFSET);
300 
301 	if (PFN_UP(ramstart) > ARCH_PFN_OFFSET) {
302 		pr_info("Wasting %lu bytes for tracking %lu unused pages\n",
303 			(unsigned long)((PFN_UP(ramstart) - ARCH_PFN_OFFSET) * sizeof(struct page)),
304 			(unsigned long)(PFN_UP(ramstart) - ARCH_PFN_OFFSET));
305 	}
306 #endif
307 
308 	min_low_pfn = ARCH_PFN_OFFSET;
309 	max_pfn = PFN_DOWN(ramend);
310 	for_each_mem_pfn_range(i, MAX_NUMNODES, &start, &end, NULL) {
311 		/*
312 		 * Skip highmem here so we get an accurate max_low_pfn if low
313 		 * memory stops short of high memory.
314 		 * If the region overlaps HIGHMEM_START, end is clipped so
315 		 * max_pfn excludes the highmem portion.
316 		 */
317 		if (start >= PFN_DOWN(HIGHMEM_START))
318 			continue;
319 		if (end > PFN_DOWN(HIGHMEM_START))
320 			end = PFN_DOWN(HIGHMEM_START);
321 		if (end > max_low_pfn)
322 			max_low_pfn = end;
323 	}
324 
325 	if (min_low_pfn >= max_low_pfn)
326 		panic("Incorrect memory mapping !!!");
327 
328 	if (max_pfn > PFN_DOWN(HIGHMEM_START)) {
329 #ifdef CONFIG_HIGHMEM
330 		highstart_pfn = PFN_DOWN(HIGHMEM_START);
331 		highend_pfn = max_pfn;
332 #else
333 		max_low_pfn = PFN_DOWN(HIGHMEM_START);
334 		max_pfn = max_low_pfn;
335 #endif
336 	}
337 
338 	/*
339 	 * Reserve initrd memory if needed.
340 	 */
341 	finalize_initrd();
342 }
343 
344 #endif	/* CONFIG_SGI_IP27 */
345 
346 static int usermem __initdata;
347 
348 static int __init early_parse_mem(char *p)
349 {
350 	phys_addr_t start, size;
351 
352 	if (!p) {
353 		pr_err("mem parameter is empty, do nothing\n");
354 		return -EINVAL;
355 	}
356 
357 	/*
358 	 * If a user specifies memory size, we
359 	 * blow away any automatically generated
360 	 * size.
361 	 */
362 	if (usermem == 0) {
363 		usermem = 1;
364 		memblock_remove(memblock_start_of_DRAM(),
365 			memblock_end_of_DRAM() - memblock_start_of_DRAM());
366 	}
367 	start = 0;
368 	size = memparse(p, &p);
369 	if (*p == '@')
370 		start = memparse(p + 1, &p);
371 
372 	if (IS_ENABLED(CONFIG_NUMA))
373 		memblock_add_node(start, size, pa_to_nid(start), MEMBLOCK_NONE);
374 	else
375 		memblock_add(start, size);
376 
377 	return 0;
378 }
379 early_param("mem", early_parse_mem);
380 
381 static int __init early_parse_memmap(char *p)
382 {
383 	char *oldp;
384 	u64 start_at, mem_size;
385 
386 	if (!p)
387 		return -EINVAL;
388 
389 	if (!strncmp(p, "exactmap", 8)) {
390 		pr_err("\"memmap=exactmap\" invalid on MIPS\n");
391 		return 0;
392 	}
393 
394 	oldp = p;
395 	mem_size = memparse(p, &p);
396 	if (p == oldp)
397 		return -EINVAL;
398 
399 	if (*p == '@') {
400 		start_at = memparse(p+1, &p);
401 		memblock_add(start_at, mem_size);
402 	} else if (*p == '#') {
403 		pr_err("\"memmap=nn#ss\" (force ACPI data) invalid on MIPS\n");
404 		return -EINVAL;
405 	} else if (*p == '$') {
406 		start_at = memparse(p+1, &p);
407 		memblock_add(start_at, mem_size);
408 		memblock_reserve(start_at, mem_size);
409 	} else {
410 		pr_err("\"memmap\" invalid format!\n");
411 		return -EINVAL;
412 	}
413 
414 	if (*p == '\0') {
415 		usermem = 1;
416 		return 0;
417 	} else
418 		return -EINVAL;
419 }
420 early_param("memmap", early_parse_memmap);
421 
422 static void __init mips_reserve_vmcore(void)
423 {
424 #ifdef CONFIG_PROC_VMCORE
425 	phys_addr_t start, end;
426 	u64 i;
427 
428 	if (!elfcorehdr_size) {
429 		for_each_mem_range(i, &start, &end) {
430 			if (elfcorehdr_addr >= start && elfcorehdr_addr < end) {
431 				/*
432 				 * Reserve from the elf core header to the end of
433 				 * the memory segment, that should all be kdump
434 				 * reserved memory.
435 				 */
436 				elfcorehdr_size = end - elfcorehdr_addr;
437 				break;
438 			}
439 		}
440 	}
441 
442 	pr_info("Reserving %ldKB of memory at %ldKB for kdump\n",
443 		(unsigned long)elfcorehdr_size >> 10, (unsigned long)elfcorehdr_addr >> 10);
444 
445 	memblock_reserve(elfcorehdr_addr, elfcorehdr_size);
446 #endif
447 }
448 
449 #ifdef CONFIG_KEXEC
450 
451 /* 64M alignment for crash kernel regions */
452 #define CRASH_ALIGN	SZ_64M
453 #define CRASH_ADDR_MAX	SZ_512M
454 
455 static void __init mips_parse_crashkernel(void)
456 {
457 	unsigned long long total_mem;
458 	unsigned long long crash_size, crash_base;
459 	int ret;
460 
461 	total_mem = memblock_phys_mem_size();
462 	ret = parse_crashkernel(boot_command_line, total_mem,
463 				&crash_size, &crash_base,
464 				NULL, NULL);
465 	if (ret != 0 || crash_size <= 0)
466 		return;
467 
468 	if (crash_base <= 0) {
469 		crash_base = memblock_phys_alloc_range(crash_size, CRASH_ALIGN,
470 						       CRASH_ALIGN,
471 						       CRASH_ADDR_MAX);
472 		if (!crash_base) {
473 			pr_warn("crashkernel reservation failed - No suitable area found.\n");
474 			return;
475 		}
476 	} else {
477 		unsigned long long start;
478 
479 		start = memblock_phys_alloc_range(crash_size, 1,
480 						  crash_base,
481 						  crash_base + crash_size);
482 		if (start != crash_base) {
483 			pr_warn("Invalid memory region reserved for crash kernel\n");
484 			return;
485 		}
486 	}
487 
488 	crashk_res.start = crash_base;
489 	crashk_res.end	 = crash_base + crash_size - 1;
490 }
491 
492 static void __init request_crashkernel(struct resource *res)
493 {
494 	int ret;
495 
496 	if (crashk_res.start == crashk_res.end)
497 		return;
498 
499 	ret = request_resource(res, &crashk_res);
500 	if (!ret)
501 		pr_info("Reserving %ldMB of memory at %ldMB for crashkernel\n",
502 			(unsigned long)(resource_size(&crashk_res) >> 20),
503 			(unsigned long)(crashk_res.start  >> 20));
504 }
505 #else /* !defined(CONFIG_KEXEC)		*/
506 static void __init mips_parse_crashkernel(void)
507 {
508 }
509 
510 static void __init request_crashkernel(struct resource *res)
511 {
512 }
513 #endif /* !defined(CONFIG_KEXEC)  */
514 
515 static void __init check_kernel_sections_mem(void)
516 {
517 	phys_addr_t start = __pa_symbol(&_text);
518 	phys_addr_t size = __pa_symbol(&_end) - start;
519 
520 	if (!memblock_is_region_memory(start, size)) {
521 		pr_info("Kernel sections are not in the memory maps\n");
522 		memblock_add(start, size);
523 	}
524 }
525 
526 static void __init bootcmdline_append(const char *s, size_t max)
527 {
528 	if (!s[0] || !max)
529 		return;
530 
531 	if (boot_command_line[0])
532 		strlcat(boot_command_line, " ", COMMAND_LINE_SIZE);
533 
534 	strlcat(boot_command_line, s, max);
535 }
536 
537 #ifdef CONFIG_OF_EARLY_FLATTREE
538 
539 static int __init bootcmdline_scan_chosen(unsigned long node, const char *uname,
540 					  int depth, void *data)
541 {
542 	bool *dt_bootargs = data;
543 	const char *p;
544 	int l;
545 
546 	if (depth != 1 || !data ||
547 	    (strcmp(uname, "chosen") != 0 && strcmp(uname, "chosen@0") != 0))
548 		return 0;
549 
550 	p = of_get_flat_dt_prop(node, "bootargs", &l);
551 	if (p != NULL && l > 0) {
552 		bootcmdline_append(p, min(l, COMMAND_LINE_SIZE));
553 		*dt_bootargs = true;
554 	}
555 
556 	return 1;
557 }
558 
559 #endif /* CONFIG_OF_EARLY_FLATTREE */
560 
561 static void __init bootcmdline_init(void)
562 {
563 	bool dt_bootargs = false;
564 
565 	/*
566 	 * If CMDLINE_OVERRIDE is enabled then initializing the command line is
567 	 * trivial - we simply use the built-in command line unconditionally &
568 	 * unmodified.
569 	 */
570 	if (IS_ENABLED(CONFIG_CMDLINE_OVERRIDE)) {
571 		strscpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);
572 		return;
573 	}
574 
575 	/*
576 	 * If the user specified a built-in command line &
577 	 * MIPS_CMDLINE_BUILTIN_EXTEND, then the built-in command line is
578 	 * prepended to arguments from the bootloader or DT so we'll copy them
579 	 * to the start of boot_command_line here. Otherwise, empty
580 	 * boot_command_line to undo anything early_init_dt_scan_chosen() did.
581 	 */
582 	if (IS_ENABLED(CONFIG_MIPS_CMDLINE_BUILTIN_EXTEND))
583 		strscpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);
584 	else
585 		boot_command_line[0] = 0;
586 
587 #ifdef CONFIG_OF_EARLY_FLATTREE
588 	/*
589 	 * If we're configured to take boot arguments from DT, look for those
590 	 * now.
591 	 */
592 	if (IS_ENABLED(CONFIG_MIPS_CMDLINE_FROM_DTB) ||
593 	    IS_ENABLED(CONFIG_MIPS_CMDLINE_DTB_EXTEND))
594 		of_scan_flat_dt(bootcmdline_scan_chosen, &dt_bootargs);
595 #endif
596 
597 	/*
598 	 * If we didn't get any arguments from DT (regardless of whether that's
599 	 * because we weren't configured to look for them, or because we looked
600 	 * & found none) then we'll take arguments from the bootloader.
601 	 * plat_mem_setup() should have filled arcs_cmdline with arguments from
602 	 * the bootloader.
603 	 */
604 	if (IS_ENABLED(CONFIG_MIPS_CMDLINE_DTB_EXTEND) || !dt_bootargs)
605 		bootcmdline_append(arcs_cmdline, COMMAND_LINE_SIZE);
606 
607 	/*
608 	 * If the user specified a built-in command line & we didn't already
609 	 * prepend it, we append it to boot_command_line here.
610 	 */
611 	if (IS_ENABLED(CONFIG_CMDLINE_BOOL) &&
612 	    !IS_ENABLED(CONFIG_MIPS_CMDLINE_BUILTIN_EXTEND))
613 		bootcmdline_append(builtin_cmdline, COMMAND_LINE_SIZE);
614 }
615 
616 /*
617  * arch_mem_init - initialize memory management subsystem
618  *
619  *  o plat_mem_setup() detects the memory configuration and will record detected
620  *    memory areas using memblock_add.
621  *
622  * At this stage the memory configuration of the system is known to the
623  * kernel but generic memory management system is still entirely uninitialized.
624  *
625  *  o bootmem_init()
626  *  o sparse_init()
627  *  o paging_init()
628  *  o dma_contiguous_reserve()
629  *
630  * At this stage the bootmem allocator is ready to use.
631  *
632  * NOTE: historically plat_mem_setup did the entire platform initialization.
633  *	 This was rather impractical because it meant plat_mem_setup had to
634  * get away without any kind of memory allocator.  To keep old code from
635  * breaking plat_setup was just renamed to plat_mem_setup and a second platform
636  * initialization hook for anything else was introduced.
637  */
638 static void __init arch_mem_init(char **cmdline_p)
639 {
640 	/* call board setup routine */
641 	plat_mem_setup();
642 	memblock_set_bottom_up(true);
643 
644 	bootcmdline_init();
645 	strscpy(command_line, boot_command_line, COMMAND_LINE_SIZE);
646 	*cmdline_p = command_line;
647 
648 	parse_early_param();
649 
650 	if (usermem)
651 		pr_info("User-defined physical RAM map overwrite\n");
652 
653 	check_kernel_sections_mem();
654 
655 	early_init_fdt_reserve_self();
656 	early_init_fdt_scan_reserved_mem();
657 
658 #ifndef CONFIG_NUMA
659 	memblock_set_node(0, PHYS_ADDR_MAX, &memblock.memory, 0);
660 #endif
661 	bootmem_init();
662 
663 	/*
664 	 * Prevent memblock from allocating high memory.
665 	 * This cannot be done before max_low_pfn is detected, so up
666 	 * to this point is possible to only reserve physical memory
667 	 * with memblock_reserve; memblock_alloc* can be used
668 	 * only after this point
669 	 */
670 	memblock_set_current_limit(PFN_PHYS(max_low_pfn));
671 
672 	mips_reserve_vmcore();
673 
674 	mips_parse_crashkernel();
675 	device_tree_init();
676 
677 	/*
678 	 * In order to reduce the possibility of kernel panic when failed to
679 	 * get IO TLB memory under CONFIG_SWIOTLB, it is better to allocate
680 	 * low memory as small as possible before plat_swiotlb_setup(), so
681 	 * make sparse_init() using top-down allocation.
682 	 */
683 	memblock_set_bottom_up(false);
684 	sparse_init();
685 	memblock_set_bottom_up(true);
686 
687 	plat_swiotlb_setup();
688 
689 	dma_contiguous_reserve(PFN_PHYS(max_low_pfn));
690 
691 	/* Reserve for hibernation. */
692 	memblock_reserve(__pa_symbol(&__nosave_begin),
693 		__pa_symbol(&__nosave_end) - __pa_symbol(&__nosave_begin));
694 
695 	early_memtest(PFN_PHYS(ARCH_PFN_OFFSET), PFN_PHYS(max_low_pfn));
696 }
697 
698 static void __init resource_init(void)
699 {
700 	phys_addr_t start, end;
701 	u64 i;
702 
703 	if (UNCAC_BASE != IO_BASE)
704 		return;
705 
706 	code_resource.start = __pa_symbol(&_text);
707 	code_resource.end = __pa_symbol(&_etext) - 1;
708 	data_resource.start = __pa_symbol(&_etext);
709 	data_resource.end = __pa_symbol(&_edata) - 1;
710 	bss_resource.start = __pa_symbol(&__bss_start);
711 	bss_resource.end = __pa_symbol(&__bss_stop) - 1;
712 
713 	for_each_mem_range(i, &start, &end) {
714 		struct resource *res;
715 
716 		res = memblock_alloc(sizeof(struct resource), SMP_CACHE_BYTES);
717 		if (!res)
718 			panic("%s: Failed to allocate %zu bytes\n", __func__,
719 			      sizeof(struct resource));
720 
721 		res->start = start;
722 		/*
723 		 * In memblock, end points to the first byte after the
724 		 * range while in resourses, end points to the last byte in
725 		 * the range.
726 		 */
727 		res->end = end - 1;
728 		res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
729 		res->name = "System RAM";
730 
731 		request_resource(&iomem_resource, res);
732 
733 		/*
734 		 *  We don't know which RAM region contains kernel data,
735 		 *  so we try it repeatedly and let the resource manager
736 		 *  test it.
737 		 */
738 		request_resource(res, &code_resource);
739 		request_resource(res, &data_resource);
740 		request_resource(res, &bss_resource);
741 		request_crashkernel(res);
742 	}
743 }
744 
745 #ifdef CONFIG_SMP
746 static void __init prefill_possible_map(void)
747 {
748 	int i, possible = num_possible_cpus();
749 
750 	if (possible > nr_cpu_ids)
751 		possible = nr_cpu_ids;
752 
753 	for (i = 0; i < possible; i++)
754 		set_cpu_possible(i, true);
755 	for (; i < NR_CPUS; i++)
756 		set_cpu_possible(i, false);
757 
758 	set_nr_cpu_ids(possible);
759 }
760 #else
761 static inline void prefill_possible_map(void) {}
762 #endif
763 
764 static void __init setup_rng_seed(void)
765 {
766 	char *rng_seed_hex = fw_getenv("rngseed");
767 	u8 rng_seed[512];
768 	size_t len;
769 
770 	if (!rng_seed_hex)
771 		return;
772 
773 	len = min(sizeof(rng_seed), strlen(rng_seed_hex) / 2);
774 	if (hex2bin(rng_seed, rng_seed_hex, len))
775 		return;
776 
777 	add_bootloader_randomness(rng_seed, len);
778 	memzero_explicit(rng_seed, len);
779 	memzero_explicit(rng_seed_hex, len * 2);
780 }
781 
782 void __init setup_arch(char **cmdline_p)
783 {
784 	cpu_probe();
785 	mips_cm_probe();
786 	prom_init();
787 
788 	setup_early_fdc_console();
789 #ifdef CONFIG_EARLY_PRINTK
790 	setup_early_printk();
791 #endif
792 	cpu_report();
793 	if (IS_ENABLED(CONFIG_CPU_R4X00_BUGS64))
794 		check_bugs64_early();
795 
796 #if defined(CONFIG_VT)
797 #if defined(CONFIG_VGA_CONSOLE)
798 	conswitchp = &vga_con;
799 #endif
800 #endif
801 
802 	arch_mem_init(cmdline_p);
803 	dmi_setup();
804 
805 	resource_init();
806 	plat_smp_setup();
807 	prefill_possible_map();
808 
809 	cpu_cache_init();
810 	paging_init();
811 
812 	memblock_dump_all();
813 
814 	setup_rng_seed();
815 }
816 
817 unsigned long kernelsp[NR_CPUS];
818 unsigned long fw_arg0, fw_arg1, fw_arg2, fw_arg3;
819 
820 #ifdef CONFIG_DEBUG_FS
821 struct dentry *mips_debugfs_dir;
822 static int __init debugfs_mips(void)
823 {
824 	mips_debugfs_dir = debugfs_create_dir("mips", NULL);
825 	return 0;
826 }
827 arch_initcall(debugfs_mips);
828 #endif
829 
830 #ifdef CONFIG_DMA_NONCOHERENT
831 static int __init setcoherentio(char *str)
832 {
833 	dma_default_coherent = true;
834 	pr_info("Hardware DMA cache coherency (command line)\n");
835 	return 0;
836 }
837 early_param("coherentio", setcoherentio);
838 
839 static int __init setnocoherentio(char *str)
840 {
841 	dma_default_coherent = false;
842 	pr_info("Software DMA cache coherency (command line)\n");
843 	return 0;
844 }
845 early_param("nocoherentio", setnocoherentio);
846 #endif
847 
848 void __init arch_cpu_finalize_init(void)
849 {
850 	unsigned int cpu = smp_processor_id();
851 
852 	cpu_data[cpu].udelay_val = loops_per_jiffy;
853 	check_bugs32();
854 
855 	if (IS_ENABLED(CONFIG_CPU_R4X00_BUGS64))
856 		check_bugs64();
857 }
858