xref: /linux/arch/x86/kernel/setup.c (revision 26fbb4c8c7c3ee9a4c3b4de555a8587b5a19154e)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *  Copyright (C) 1995  Linus Torvalds
4  *
5  * This file contains the setup_arch() code, which handles the architecture-dependent
6  * parts of early kernel initialization.
7  */
8 #include <linux/console.h>
9 #include <linux/crash_dump.h>
10 #include <linux/dma-map-ops.h>
11 #include <linux/dmi.h>
12 #include <linux/efi.h>
13 #include <linux/init_ohci1394_dma.h>
14 #include <linux/initrd.h>
15 #include <linux/iscsi_ibft.h>
16 #include <linux/memblock.h>
17 #include <linux/pci.h>
18 #include <linux/root_dev.h>
19 #include <linux/sfi.h>
20 #include <linux/hugetlb.h>
21 #include <linux/tboot.h>
22 #include <linux/usb/xhci-dbgp.h>
23 #include <linux/static_call.h>
24 #include <linux/swiotlb.h>
25 
26 #include <uapi/linux/mount.h>
27 
28 #include <xen/xen.h>
29 
30 #include <asm/apic.h>
31 #include <asm/numa.h>
32 #include <asm/bios_ebda.h>
33 #include <asm/bugs.h>
34 #include <asm/cpu.h>
35 #include <asm/efi.h>
36 #include <asm/gart.h>
37 #include <asm/hypervisor.h>
38 #include <asm/io_apic.h>
39 #include <asm/kasan.h>
40 #include <asm/kaslr.h>
41 #include <asm/mce.h>
42 #include <asm/mtrr.h>
43 #include <asm/realmode.h>
44 #include <asm/olpc_ofw.h>
45 #include <asm/pci-direct.h>
46 #include <asm/prom.h>
47 #include <asm/proto.h>
48 #include <asm/unwind.h>
49 #include <asm/vsyscall.h>
50 #include <linux/vmalloc.h>
51 
52 /*
53  * max_low_pfn_mapped: highest directly mapped pfn < 4 GB
54  * max_pfn_mapped:     highest directly mapped pfn > 4 GB
55  *
56  * The direct mapping only covers E820_TYPE_RAM regions, so the ranges and gaps are
57  * represented by pfn_mapped[].
58  */
59 unsigned long max_low_pfn_mapped;
60 unsigned long max_pfn_mapped;
61 
62 #ifdef CONFIG_DMI
63 RESERVE_BRK(dmi_alloc, 65536);
64 #endif
65 
66 
67 /*
68  * Range of the BSS area. The size of the BSS area is determined
69  * at link time, with RESERVE_BRK*() facility reserving additional
70  * chunks.
71  */
72 unsigned long _brk_start = (unsigned long)__brk_base;
73 unsigned long _brk_end   = (unsigned long)__brk_base;
74 
75 struct boot_params boot_params;
76 
77 /*
78  * These are the four main kernel memory regions, we put them into
79  * the resource tree so that kdump tools and other debugging tools
80  * recover it:
81  */
82 
83 static struct resource rodata_resource = {
84 	.name	= "Kernel rodata",
85 	.start	= 0,
86 	.end	= 0,
87 	.flags	= IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM
88 };
89 
90 static struct resource data_resource = {
91 	.name	= "Kernel data",
92 	.start	= 0,
93 	.end	= 0,
94 	.flags	= IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM
95 };
96 
97 static struct resource code_resource = {
98 	.name	= "Kernel code",
99 	.start	= 0,
100 	.end	= 0,
101 	.flags	= IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM
102 };
103 
104 static struct resource bss_resource = {
105 	.name	= "Kernel bss",
106 	.start	= 0,
107 	.end	= 0,
108 	.flags	= IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM
109 };
110 
111 
112 #ifdef CONFIG_X86_32
113 /* CPU data as detected by the assembly code in head_32.S */
114 struct cpuinfo_x86 new_cpu_data;
115 
116 /* Common CPU data for all CPUs */
117 struct cpuinfo_x86 boot_cpu_data __read_mostly;
118 EXPORT_SYMBOL(boot_cpu_data);
119 
120 unsigned int def_to_bigsmp;
121 
122 struct apm_info apm_info;
123 EXPORT_SYMBOL(apm_info);
124 
125 #if defined(CONFIG_X86_SPEEDSTEP_SMI) || \
126 	defined(CONFIG_X86_SPEEDSTEP_SMI_MODULE)
127 struct ist_info ist_info;
128 EXPORT_SYMBOL(ist_info);
129 #else
130 struct ist_info ist_info;
131 #endif
132 
133 #else
134 struct cpuinfo_x86 boot_cpu_data __read_mostly;
135 EXPORT_SYMBOL(boot_cpu_data);
136 #endif
137 
138 
139 #if !defined(CONFIG_X86_PAE) || defined(CONFIG_X86_64)
140 __visible unsigned long mmu_cr4_features __ro_after_init;
141 #else
142 __visible unsigned long mmu_cr4_features __ro_after_init = X86_CR4_PAE;
143 #endif
144 
145 /* Boot loader ID and version as integers, for the benefit of proc_dointvec */
146 int bootloader_type, bootloader_version;
147 
148 /*
149  * Setup options
150  */
151 struct screen_info screen_info;
152 EXPORT_SYMBOL(screen_info);
153 struct edid_info edid_info;
154 EXPORT_SYMBOL_GPL(edid_info);
155 
156 extern int root_mountflags;
157 
158 unsigned long saved_video_mode;
159 
160 #define RAMDISK_IMAGE_START_MASK	0x07FF
161 #define RAMDISK_PROMPT_FLAG		0x8000
162 #define RAMDISK_LOAD_FLAG		0x4000
163 
164 static char __initdata command_line[COMMAND_LINE_SIZE];
165 #ifdef CONFIG_CMDLINE_BOOL
166 static char __initdata builtin_cmdline[COMMAND_LINE_SIZE] = CONFIG_CMDLINE;
167 #endif
168 
169 #if defined(CONFIG_EDD) || defined(CONFIG_EDD_MODULE)
170 struct edd edd;
171 #ifdef CONFIG_EDD_MODULE
172 EXPORT_SYMBOL(edd);
173 #endif
174 /**
175  * copy_edd() - Copy the BIOS EDD information
176  *              from boot_params into a safe place.
177  *
178  */
179 static inline void __init copy_edd(void)
180 {
181      memcpy(edd.mbr_signature, boot_params.edd_mbr_sig_buffer,
182 	    sizeof(edd.mbr_signature));
183      memcpy(edd.edd_info, boot_params.eddbuf, sizeof(edd.edd_info));
184      edd.mbr_signature_nr = boot_params.edd_mbr_sig_buf_entries;
185      edd.edd_info_nr = boot_params.eddbuf_entries;
186 }
187 #else
188 static inline void __init copy_edd(void)
189 {
190 }
191 #endif
192 
193 void * __init extend_brk(size_t size, size_t align)
194 {
195 	size_t mask = align - 1;
196 	void *ret;
197 
198 	BUG_ON(_brk_start == 0);
199 	BUG_ON(align & mask);
200 
201 	_brk_end = (_brk_end + mask) & ~mask;
202 	BUG_ON((char *)(_brk_end + size) > __brk_limit);
203 
204 	ret = (void *)_brk_end;
205 	_brk_end += size;
206 
207 	memset(ret, 0, size);
208 
209 	return ret;
210 }
211 
212 #ifdef CONFIG_X86_32
213 static void __init cleanup_highmap(void)
214 {
215 }
216 #endif
217 
218 static void __init reserve_brk(void)
219 {
220 	if (_brk_end > _brk_start)
221 		memblock_reserve(__pa_symbol(_brk_start),
222 				 _brk_end - _brk_start);
223 
224 	/* Mark brk area as locked down and no longer taking any
225 	   new allocations */
226 	_brk_start = 0;
227 }
228 
229 u64 relocated_ramdisk;
230 
231 #ifdef CONFIG_BLK_DEV_INITRD
232 
233 static u64 __init get_ramdisk_image(void)
234 {
235 	u64 ramdisk_image = boot_params.hdr.ramdisk_image;
236 
237 	ramdisk_image |= (u64)boot_params.ext_ramdisk_image << 32;
238 
239 	if (ramdisk_image == 0)
240 		ramdisk_image = phys_initrd_start;
241 
242 	return ramdisk_image;
243 }
244 static u64 __init get_ramdisk_size(void)
245 {
246 	u64 ramdisk_size = boot_params.hdr.ramdisk_size;
247 
248 	ramdisk_size |= (u64)boot_params.ext_ramdisk_size << 32;
249 
250 	if (ramdisk_size == 0)
251 		ramdisk_size = phys_initrd_size;
252 
253 	return ramdisk_size;
254 }
255 
256 static void __init relocate_initrd(void)
257 {
258 	/* Assume only end is not page aligned */
259 	u64 ramdisk_image = get_ramdisk_image();
260 	u64 ramdisk_size  = get_ramdisk_size();
261 	u64 area_size     = PAGE_ALIGN(ramdisk_size);
262 
263 	/* We need to move the initrd down into directly mapped mem */
264 	relocated_ramdisk = memblock_phys_alloc_range(area_size, PAGE_SIZE, 0,
265 						      PFN_PHYS(max_pfn_mapped));
266 	if (!relocated_ramdisk)
267 		panic("Cannot find place for new RAMDISK of size %lld\n",
268 		      ramdisk_size);
269 
270 	initrd_start = relocated_ramdisk + PAGE_OFFSET;
271 	initrd_end   = initrd_start + ramdisk_size;
272 	printk(KERN_INFO "Allocated new RAMDISK: [mem %#010llx-%#010llx]\n",
273 	       relocated_ramdisk, relocated_ramdisk + ramdisk_size - 1);
274 
275 	copy_from_early_mem((void *)initrd_start, ramdisk_image, ramdisk_size);
276 
277 	printk(KERN_INFO "Move RAMDISK from [mem %#010llx-%#010llx] to"
278 		" [mem %#010llx-%#010llx]\n",
279 		ramdisk_image, ramdisk_image + ramdisk_size - 1,
280 		relocated_ramdisk, relocated_ramdisk + ramdisk_size - 1);
281 }
282 
283 static void __init early_reserve_initrd(void)
284 {
285 	/* Assume only end is not page aligned */
286 	u64 ramdisk_image = get_ramdisk_image();
287 	u64 ramdisk_size  = get_ramdisk_size();
288 	u64 ramdisk_end   = PAGE_ALIGN(ramdisk_image + ramdisk_size);
289 
290 	if (!boot_params.hdr.type_of_loader ||
291 	    !ramdisk_image || !ramdisk_size)
292 		return;		/* No initrd provided by bootloader */
293 
294 	memblock_reserve(ramdisk_image, ramdisk_end - ramdisk_image);
295 }
296 
297 static void __init reserve_initrd(void)
298 {
299 	/* Assume only end is not page aligned */
300 	u64 ramdisk_image = get_ramdisk_image();
301 	u64 ramdisk_size  = get_ramdisk_size();
302 	u64 ramdisk_end   = PAGE_ALIGN(ramdisk_image + ramdisk_size);
303 
304 	if (!boot_params.hdr.type_of_loader ||
305 	    !ramdisk_image || !ramdisk_size)
306 		return;		/* No initrd provided by bootloader */
307 
308 	initrd_start = 0;
309 
310 	printk(KERN_INFO "RAMDISK: [mem %#010llx-%#010llx]\n", ramdisk_image,
311 			ramdisk_end - 1);
312 
313 	if (pfn_range_is_mapped(PFN_DOWN(ramdisk_image),
314 				PFN_DOWN(ramdisk_end))) {
315 		/* All are mapped, easy case */
316 		initrd_start = ramdisk_image + PAGE_OFFSET;
317 		initrd_end = initrd_start + ramdisk_size;
318 		return;
319 	}
320 
321 	relocate_initrd();
322 
323 	memblock_free(ramdisk_image, ramdisk_end - ramdisk_image);
324 }
325 
326 #else
327 static void __init early_reserve_initrd(void)
328 {
329 }
330 static void __init reserve_initrd(void)
331 {
332 }
333 #endif /* CONFIG_BLK_DEV_INITRD */
334 
335 static void __init parse_setup_data(void)
336 {
337 	struct setup_data *data;
338 	u64 pa_data, pa_next;
339 
340 	pa_data = boot_params.hdr.setup_data;
341 	while (pa_data) {
342 		u32 data_len, data_type;
343 
344 		data = early_memremap(pa_data, sizeof(*data));
345 		data_len = data->len + sizeof(struct setup_data);
346 		data_type = data->type;
347 		pa_next = data->next;
348 		early_memunmap(data, sizeof(*data));
349 
350 		switch (data_type) {
351 		case SETUP_E820_EXT:
352 			e820__memory_setup_extended(pa_data, data_len);
353 			break;
354 		case SETUP_DTB:
355 			add_dtb(pa_data);
356 			break;
357 		case SETUP_EFI:
358 			parse_efi_setup(pa_data, data_len);
359 			break;
360 		default:
361 			break;
362 		}
363 		pa_data = pa_next;
364 	}
365 }
366 
367 static void __init memblock_x86_reserve_range_setup_data(void)
368 {
369 	struct setup_data *data;
370 	u64 pa_data;
371 
372 	pa_data = boot_params.hdr.setup_data;
373 	while (pa_data) {
374 		data = early_memremap(pa_data, sizeof(*data));
375 		memblock_reserve(pa_data, sizeof(*data) + data->len);
376 
377 		if (data->type == SETUP_INDIRECT &&
378 		    ((struct setup_indirect *)data->data)->type != SETUP_INDIRECT)
379 			memblock_reserve(((struct setup_indirect *)data->data)->addr,
380 					 ((struct setup_indirect *)data->data)->len);
381 
382 		pa_data = data->next;
383 		early_memunmap(data, sizeof(*data));
384 	}
385 }
386 
387 /*
388  * --------- Crashkernel reservation ------------------------------
389  */
390 
391 #ifdef CONFIG_KEXEC_CORE
392 
393 /* 16M alignment for crash kernel regions */
394 #define CRASH_ALIGN		SZ_16M
395 
396 /*
397  * Keep the crash kernel below this limit.
398  *
399  * Earlier 32-bits kernels would limit the kernel to the low 512 MB range
400  * due to mapping restrictions.
401  *
402  * 64-bit kdump kernels need to be restricted to be under 64 TB, which is
403  * the upper limit of system RAM in 4-level paging mode. Since the kdump
404  * jump could be from 5-level paging to 4-level paging, the jump will fail if
405  * the kernel is put above 64 TB, and during the 1st kernel bootup there's
406  * no good way to detect the paging mode of the target kernel which will be
407  * loaded for dumping.
408  */
409 #ifdef CONFIG_X86_32
410 # define CRASH_ADDR_LOW_MAX	SZ_512M
411 # define CRASH_ADDR_HIGH_MAX	SZ_512M
412 #else
413 # define CRASH_ADDR_LOW_MAX	SZ_4G
414 # define CRASH_ADDR_HIGH_MAX	SZ_64T
415 #endif
416 
417 static int __init reserve_crashkernel_low(void)
418 {
419 #ifdef CONFIG_X86_64
420 	unsigned long long base, low_base = 0, low_size = 0;
421 	unsigned long low_mem_limit;
422 	int ret;
423 
424 	low_mem_limit = min(memblock_phys_mem_size(), CRASH_ADDR_LOW_MAX);
425 
426 	/* crashkernel=Y,low */
427 	ret = parse_crashkernel_low(boot_command_line, low_mem_limit, &low_size, &base);
428 	if (ret) {
429 		/*
430 		 * two parts from kernel/dma/swiotlb.c:
431 		 * -swiotlb size: user-specified with swiotlb= or default.
432 		 *
433 		 * -swiotlb overflow buffer: now hardcoded to 32k. We round it
434 		 * to 8M for other buffers that may need to stay low too. Also
435 		 * make sure we allocate enough extra low memory so that we
436 		 * don't run out of DMA buffers for 32-bit devices.
437 		 */
438 		low_size = max(swiotlb_size_or_default() + (8UL << 20), 256UL << 20);
439 	} else {
440 		/* passed with crashkernel=0,low ? */
441 		if (!low_size)
442 			return 0;
443 	}
444 
445 	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, 0, CRASH_ADDR_LOW_MAX);
446 	if (!low_base) {
447 		pr_err("Cannot reserve %ldMB crashkernel low memory, please try smaller size.\n",
448 		       (unsigned long)(low_size >> 20));
449 		return -ENOMEM;
450 	}
451 
452 	pr_info("Reserving %ldMB of low memory at %ldMB for crashkernel (low RAM limit: %ldMB)\n",
453 		(unsigned long)(low_size >> 20),
454 		(unsigned long)(low_base >> 20),
455 		(unsigned long)(low_mem_limit >> 20));
456 
457 	crashk_low_res.start = low_base;
458 	crashk_low_res.end   = low_base + low_size - 1;
459 	insert_resource(&iomem_resource, &crashk_low_res);
460 #endif
461 	return 0;
462 }
463 
464 static void __init reserve_crashkernel(void)
465 {
466 	unsigned long long crash_size, crash_base, total_mem;
467 	bool high = false;
468 	int ret;
469 
470 	total_mem = memblock_phys_mem_size();
471 
472 	/* crashkernel=XM */
473 	ret = parse_crashkernel(boot_command_line, total_mem, &crash_size, &crash_base);
474 	if (ret != 0 || crash_size <= 0) {
475 		/* crashkernel=X,high */
476 		ret = parse_crashkernel_high(boot_command_line, total_mem,
477 					     &crash_size, &crash_base);
478 		if (ret != 0 || crash_size <= 0)
479 			return;
480 		high = true;
481 	}
482 
483 	if (xen_pv_domain()) {
484 		pr_info("Ignoring crashkernel for a Xen PV domain\n");
485 		return;
486 	}
487 
488 	/* 0 means: find the address automatically */
489 	if (!crash_base) {
490 		/*
491 		 * Set CRASH_ADDR_LOW_MAX upper bound for crash memory,
492 		 * crashkernel=x,high reserves memory over 4G, also allocates
493 		 * 256M extra low memory for DMA buffers and swiotlb.
494 		 * But the extra memory is not required for all machines.
495 		 * So try low memory first and fall back to high memory
496 		 * unless "crashkernel=size[KMG],high" is specified.
497 		 */
498 		if (!high)
499 			crash_base = memblock_phys_alloc_range(crash_size,
500 						CRASH_ALIGN, CRASH_ALIGN,
501 						CRASH_ADDR_LOW_MAX);
502 		if (!crash_base)
503 			crash_base = memblock_phys_alloc_range(crash_size,
504 						CRASH_ALIGN, CRASH_ALIGN,
505 						CRASH_ADDR_HIGH_MAX);
506 		if (!crash_base) {
507 			pr_info("crashkernel reservation failed - No suitable area found.\n");
508 			return;
509 		}
510 	} else {
511 		unsigned long long start;
512 
513 		start = memblock_phys_alloc_range(crash_size, SZ_1M, crash_base,
514 						  crash_base + crash_size);
515 		if (start != crash_base) {
516 			pr_info("crashkernel reservation failed - memory is in use.\n");
517 			return;
518 		}
519 	}
520 
521 	if (crash_base >= (1ULL << 32) && reserve_crashkernel_low()) {
522 		memblock_free(crash_base, crash_size);
523 		return;
524 	}
525 
526 	pr_info("Reserving %ldMB of memory at %ldMB for crashkernel (System RAM: %ldMB)\n",
527 		(unsigned long)(crash_size >> 20),
528 		(unsigned long)(crash_base >> 20),
529 		(unsigned long)(total_mem >> 20));
530 
531 	crashk_res.start = crash_base;
532 	crashk_res.end   = crash_base + crash_size - 1;
533 	insert_resource(&iomem_resource, &crashk_res);
534 }
535 #else
536 static void __init reserve_crashkernel(void)
537 {
538 }
539 #endif
540 
541 static struct resource standard_io_resources[] = {
542 	{ .name = "dma1", .start = 0x00, .end = 0x1f,
543 		.flags = IORESOURCE_BUSY | IORESOURCE_IO },
544 	{ .name = "pic1", .start = 0x20, .end = 0x21,
545 		.flags = IORESOURCE_BUSY | IORESOURCE_IO },
546 	{ .name = "timer0", .start = 0x40, .end = 0x43,
547 		.flags = IORESOURCE_BUSY | IORESOURCE_IO },
548 	{ .name = "timer1", .start = 0x50, .end = 0x53,
549 		.flags = IORESOURCE_BUSY | IORESOURCE_IO },
550 	{ .name = "keyboard", .start = 0x60, .end = 0x60,
551 		.flags = IORESOURCE_BUSY | IORESOURCE_IO },
552 	{ .name = "keyboard", .start = 0x64, .end = 0x64,
553 		.flags = IORESOURCE_BUSY | IORESOURCE_IO },
554 	{ .name = "dma page reg", .start = 0x80, .end = 0x8f,
555 		.flags = IORESOURCE_BUSY | IORESOURCE_IO },
556 	{ .name = "pic2", .start = 0xa0, .end = 0xa1,
557 		.flags = IORESOURCE_BUSY | IORESOURCE_IO },
558 	{ .name = "dma2", .start = 0xc0, .end = 0xdf,
559 		.flags = IORESOURCE_BUSY | IORESOURCE_IO },
560 	{ .name = "fpu", .start = 0xf0, .end = 0xff,
561 		.flags = IORESOURCE_BUSY | IORESOURCE_IO }
562 };
563 
564 void __init reserve_standard_io_resources(void)
565 {
566 	int i;
567 
568 	/* request I/O space for devices used on all i[345]86 PCs */
569 	for (i = 0; i < ARRAY_SIZE(standard_io_resources); i++)
570 		request_resource(&ioport_resource, &standard_io_resources[i]);
571 
572 }
573 
574 static __init void reserve_ibft_region(void)
575 {
576 	unsigned long addr, size = 0;
577 
578 	addr = find_ibft_region(&size);
579 
580 	if (size)
581 		memblock_reserve(addr, size);
582 }
583 
584 static bool __init snb_gfx_workaround_needed(void)
585 {
586 #ifdef CONFIG_PCI
587 	int i;
588 	u16 vendor, devid;
589 	static const __initconst u16 snb_ids[] = {
590 		0x0102,
591 		0x0112,
592 		0x0122,
593 		0x0106,
594 		0x0116,
595 		0x0126,
596 		0x010a,
597 	};
598 
599 	/* Assume no if something weird is going on with PCI */
600 	if (!early_pci_allowed())
601 		return false;
602 
603 	vendor = read_pci_config_16(0, 2, 0, PCI_VENDOR_ID);
604 	if (vendor != 0x8086)
605 		return false;
606 
607 	devid = read_pci_config_16(0, 2, 0, PCI_DEVICE_ID);
608 	for (i = 0; i < ARRAY_SIZE(snb_ids); i++)
609 		if (devid == snb_ids[i])
610 			return true;
611 #endif
612 
613 	return false;
614 }
615 
616 /*
617  * Sandy Bridge graphics has trouble with certain ranges, exclude
618  * them from allocation.
619  */
620 static void __init trim_snb_memory(void)
621 {
622 	static const __initconst unsigned long bad_pages[] = {
623 		0x20050000,
624 		0x20110000,
625 		0x20130000,
626 		0x20138000,
627 		0x40004000,
628 	};
629 	int i;
630 
631 	if (!snb_gfx_workaround_needed())
632 		return;
633 
634 	printk(KERN_DEBUG "reserving inaccessible SNB gfx pages\n");
635 
636 	/*
637 	 * Reserve all memory below the 1 MB mark that has not
638 	 * already been reserved.
639 	 */
640 	memblock_reserve(0, 1<<20);
641 
642 	for (i = 0; i < ARRAY_SIZE(bad_pages); i++) {
643 		if (memblock_reserve(bad_pages[i], PAGE_SIZE))
644 			printk(KERN_WARNING "failed to reserve 0x%08lx\n",
645 			       bad_pages[i]);
646 	}
647 }
648 
649 /*
650  * Here we put platform-specific memory range workarounds, i.e.
651  * memory known to be corrupt or otherwise in need to be reserved on
652  * specific platforms.
653  *
654  * If this gets used more widely it could use a real dispatch mechanism.
655  */
656 static void __init trim_platform_memory_ranges(void)
657 {
658 	trim_snb_memory();
659 }
660 
661 static void __init trim_bios_range(void)
662 {
663 	/*
664 	 * special case: Some BIOSes report the PC BIOS
665 	 * area (640Kb -> 1Mb) as RAM even though it is not.
666 	 * take them out.
667 	 */
668 	e820__range_remove(BIOS_BEGIN, BIOS_END - BIOS_BEGIN, E820_TYPE_RAM, 1);
669 
670 	e820__update_table(e820_table);
671 }
672 
673 /* called before trim_bios_range() to spare extra sanitize */
674 static void __init e820_add_kernel_range(void)
675 {
676 	u64 start = __pa_symbol(_text);
677 	u64 size = __pa_symbol(_end) - start;
678 
679 	/*
680 	 * Complain if .text .data and .bss are not marked as E820_TYPE_RAM and
681 	 * attempt to fix it by adding the range. We may have a confused BIOS,
682 	 * or the user may have used memmap=exactmap or memmap=xxM$yyM to
683 	 * exclude kernel range. If we really are running on top non-RAM,
684 	 * we will crash later anyways.
685 	 */
686 	if (e820__mapped_all(start, start + size, E820_TYPE_RAM))
687 		return;
688 
689 	pr_warn(".text .data .bss are not marked as E820_TYPE_RAM!\n");
690 	e820__range_remove(start, size, E820_TYPE_RAM, 0);
691 	e820__range_add(start, size, E820_TYPE_RAM);
692 }
693 
694 static unsigned reserve_low = CONFIG_X86_RESERVE_LOW << 10;
695 
696 static int __init parse_reservelow(char *p)
697 {
698 	unsigned long long size;
699 
700 	if (!p)
701 		return -EINVAL;
702 
703 	size = memparse(p, &p);
704 
705 	if (size < 4096)
706 		size = 4096;
707 
708 	if (size > 640*1024)
709 		size = 640*1024;
710 
711 	reserve_low = size;
712 
713 	return 0;
714 }
715 
716 early_param("reservelow", parse_reservelow);
717 
718 static void __init trim_low_memory_range(void)
719 {
720 	/*
721 	 * A special case is the first 4Kb of memory;
722 	 * This is a BIOS owned area, not kernel ram, but generally
723 	 * not listed as such in the E820 table.
724 	 *
725 	 * This typically reserves additional memory (64KiB by default)
726 	 * since some BIOSes are known to corrupt low memory.  See the
727 	 * Kconfig help text for X86_RESERVE_LOW.
728 	 */
729 	memblock_reserve(0, ALIGN(reserve_low, PAGE_SIZE));
730 }
731 
732 /*
733  * Dump out kernel offset information on panic.
734  */
735 static int
736 dump_kernel_offset(struct notifier_block *self, unsigned long v, void *p)
737 {
738 	if (kaslr_enabled()) {
739 		pr_emerg("Kernel Offset: 0x%lx from 0x%lx (relocation range: 0x%lx-0x%lx)\n",
740 			 kaslr_offset(),
741 			 __START_KERNEL,
742 			 __START_KERNEL_map,
743 			 MODULES_VADDR-1);
744 	} else {
745 		pr_emerg("Kernel Offset: disabled\n");
746 	}
747 
748 	return 0;
749 }
750 
751 /*
752  * Determine if we were loaded by an EFI loader.  If so, then we have also been
753  * passed the efi memmap, systab, etc., so we should use these data structures
754  * for initialization.  Note, the efi init code path is determined by the
755  * global efi_enabled. This allows the same kernel image to be used on existing
756  * systems (with a traditional BIOS) as well as on EFI systems.
757  */
758 /*
759  * setup_arch - architecture-specific boot-time initializations
760  *
761  * Note: On x86_64, fixmaps are ready for use even before this is called.
762  */
763 
764 void __init setup_arch(char **cmdline_p)
765 {
766 	/*
767 	 * Reserve the memory occupied by the kernel between _text and
768 	 * __end_of_kernel_reserve symbols. Any kernel sections after the
769 	 * __end_of_kernel_reserve symbol must be explicitly reserved with a
770 	 * separate memblock_reserve() or they will be discarded.
771 	 */
772 	memblock_reserve(__pa_symbol(_text),
773 			 (unsigned long)__end_of_kernel_reserve - (unsigned long)_text);
774 
775 	/*
776 	 * Make sure page 0 is always reserved because on systems with
777 	 * L1TF its contents can be leaked to user processes.
778 	 */
779 	memblock_reserve(0, PAGE_SIZE);
780 
781 	early_reserve_initrd();
782 
783 	/*
784 	 * At this point everything still needed from the boot loader
785 	 * or BIOS or kernel text should be early reserved or marked not
786 	 * RAM in e820. All other memory is free game.
787 	 */
788 
789 #ifdef CONFIG_X86_32
790 	memcpy(&boot_cpu_data, &new_cpu_data, sizeof(new_cpu_data));
791 
792 	/*
793 	 * copy kernel address range established so far and switch
794 	 * to the proper swapper page table
795 	 */
796 	clone_pgd_range(swapper_pg_dir     + KERNEL_PGD_BOUNDARY,
797 			initial_page_table + KERNEL_PGD_BOUNDARY,
798 			KERNEL_PGD_PTRS);
799 
800 	load_cr3(swapper_pg_dir);
801 	/*
802 	 * Note: Quark X1000 CPUs advertise PGE incorrectly and require
803 	 * a cr3 based tlb flush, so the following __flush_tlb_all()
804 	 * will not flush anything because the CPU quirk which clears
805 	 * X86_FEATURE_PGE has not been invoked yet. Though due to the
806 	 * load_cr3() above the TLB has been flushed already. The
807 	 * quirk is invoked before subsequent calls to __flush_tlb_all()
808 	 * so proper operation is guaranteed.
809 	 */
810 	__flush_tlb_all();
811 #else
812 	printk(KERN_INFO "Command line: %s\n", boot_command_line);
813 	boot_cpu_data.x86_phys_bits = MAX_PHYSMEM_BITS;
814 #endif
815 
816 	/*
817 	 * If we have OLPC OFW, we might end up relocating the fixmap due to
818 	 * reserve_top(), so do this before touching the ioremap area.
819 	 */
820 	olpc_ofw_detect();
821 
822 	idt_setup_early_traps();
823 	early_cpu_init();
824 	arch_init_ideal_nops();
825 	jump_label_init();
826 	static_call_init();
827 	early_ioremap_init();
828 
829 	setup_olpc_ofw_pgd();
830 
831 	ROOT_DEV = old_decode_dev(boot_params.hdr.root_dev);
832 	screen_info = boot_params.screen_info;
833 	edid_info = boot_params.edid_info;
834 #ifdef CONFIG_X86_32
835 	apm_info.bios = boot_params.apm_bios_info;
836 	ist_info = boot_params.ist_info;
837 #endif
838 	saved_video_mode = boot_params.hdr.vid_mode;
839 	bootloader_type = boot_params.hdr.type_of_loader;
840 	if ((bootloader_type >> 4) == 0xe) {
841 		bootloader_type &= 0xf;
842 		bootloader_type |= (boot_params.hdr.ext_loader_type+0x10) << 4;
843 	}
844 	bootloader_version  = bootloader_type & 0xf;
845 	bootloader_version |= boot_params.hdr.ext_loader_ver << 4;
846 
847 #ifdef CONFIG_BLK_DEV_RAM
848 	rd_image_start = boot_params.hdr.ram_size & RAMDISK_IMAGE_START_MASK;
849 #endif
850 #ifdef CONFIG_EFI
851 	if (!strncmp((char *)&boot_params.efi_info.efi_loader_signature,
852 		     EFI32_LOADER_SIGNATURE, 4)) {
853 		set_bit(EFI_BOOT, &efi.flags);
854 	} else if (!strncmp((char *)&boot_params.efi_info.efi_loader_signature,
855 		     EFI64_LOADER_SIGNATURE, 4)) {
856 		set_bit(EFI_BOOT, &efi.flags);
857 		set_bit(EFI_64BIT, &efi.flags);
858 	}
859 #endif
860 
861 	x86_init.oem.arch_setup();
862 
863 	iomem_resource.end = (1ULL << boot_cpu_data.x86_phys_bits) - 1;
864 	e820__memory_setup();
865 	parse_setup_data();
866 
867 	copy_edd();
868 
869 	if (!boot_params.hdr.root_flags)
870 		root_mountflags &= ~MS_RDONLY;
871 	init_mm.start_code = (unsigned long) _text;
872 	init_mm.end_code = (unsigned long) _etext;
873 	init_mm.end_data = (unsigned long) _edata;
874 	init_mm.brk = _brk_end;
875 
876 	code_resource.start = __pa_symbol(_text);
877 	code_resource.end = __pa_symbol(_etext)-1;
878 	rodata_resource.start = __pa_symbol(__start_rodata);
879 	rodata_resource.end = __pa_symbol(__end_rodata)-1;
880 	data_resource.start = __pa_symbol(_sdata);
881 	data_resource.end = __pa_symbol(_edata)-1;
882 	bss_resource.start = __pa_symbol(__bss_start);
883 	bss_resource.end = __pa_symbol(__bss_stop)-1;
884 
885 #ifdef CONFIG_CMDLINE_BOOL
886 #ifdef CONFIG_CMDLINE_OVERRIDE
887 	strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);
888 #else
889 	if (builtin_cmdline[0]) {
890 		/* append boot loader cmdline to builtin */
891 		strlcat(builtin_cmdline, " ", COMMAND_LINE_SIZE);
892 		strlcat(builtin_cmdline, boot_command_line, COMMAND_LINE_SIZE);
893 		strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);
894 	}
895 #endif
896 #endif
897 
898 	strlcpy(command_line, boot_command_line, COMMAND_LINE_SIZE);
899 	*cmdline_p = command_line;
900 
901 	/*
902 	 * x86_configure_nx() is called before parse_early_param() to detect
903 	 * whether hardware doesn't support NX (so that the early EHCI debug
904 	 * console setup can safely call set_fixmap()). It may then be called
905 	 * again from within noexec_setup() during parsing early parameters
906 	 * to honor the respective command line option.
907 	 */
908 	x86_configure_nx();
909 
910 	parse_early_param();
911 
912 	if (efi_enabled(EFI_BOOT))
913 		efi_memblock_x86_reserve_range();
914 #ifdef CONFIG_MEMORY_HOTPLUG
915 	/*
916 	 * Memory used by the kernel cannot be hot-removed because Linux
917 	 * cannot migrate the kernel pages. When memory hotplug is
918 	 * enabled, we should prevent memblock from allocating memory
919 	 * for the kernel.
920 	 *
921 	 * ACPI SRAT records all hotpluggable memory ranges. But before
922 	 * SRAT is parsed, we don't know about it.
923 	 *
924 	 * The kernel image is loaded into memory at very early time. We
925 	 * cannot prevent this anyway. So on NUMA system, we set any
926 	 * node the kernel resides in as un-hotpluggable.
927 	 *
928 	 * Since on modern servers, one node could have double-digit
929 	 * gigabytes memory, we can assume the memory around the kernel
930 	 * image is also un-hotpluggable. So before SRAT is parsed, just
931 	 * allocate memory near the kernel image to try the best to keep
932 	 * the kernel away from hotpluggable memory.
933 	 */
934 	if (movable_node_is_enabled())
935 		memblock_set_bottom_up(true);
936 #endif
937 
938 	x86_report_nx();
939 
940 	/* after early param, so could get panic from serial */
941 	memblock_x86_reserve_range_setup_data();
942 
943 	if (acpi_mps_check()) {
944 #ifdef CONFIG_X86_LOCAL_APIC
945 		disable_apic = 1;
946 #endif
947 		setup_clear_cpu_cap(X86_FEATURE_APIC);
948 	}
949 
950 	e820__reserve_setup_data();
951 	e820__finish_early_params();
952 
953 	if (efi_enabled(EFI_BOOT))
954 		efi_init();
955 
956 	dmi_setup();
957 
958 	/*
959 	 * VMware detection requires dmi to be available, so this
960 	 * needs to be done after dmi_setup(), for the boot CPU.
961 	 */
962 	init_hypervisor_platform();
963 
964 	tsc_early_init();
965 	x86_init.resources.probe_roms();
966 
967 	/* after parse_early_param, so could debug it */
968 	insert_resource(&iomem_resource, &code_resource);
969 	insert_resource(&iomem_resource, &rodata_resource);
970 	insert_resource(&iomem_resource, &data_resource);
971 	insert_resource(&iomem_resource, &bss_resource);
972 
973 	e820_add_kernel_range();
974 	trim_bios_range();
975 #ifdef CONFIG_X86_32
976 	if (ppro_with_ram_bug()) {
977 		e820__range_update(0x70000000ULL, 0x40000ULL, E820_TYPE_RAM,
978 				  E820_TYPE_RESERVED);
979 		e820__update_table(e820_table);
980 		printk(KERN_INFO "fixed physical RAM map:\n");
981 		e820__print_table("bad_ppro");
982 	}
983 #else
984 	early_gart_iommu_check();
985 #endif
986 
987 	/*
988 	 * partially used pages are not usable - thus
989 	 * we are rounding upwards:
990 	 */
991 	max_pfn = e820__end_of_ram_pfn();
992 
993 	/* update e820 for memory not covered by WB MTRRs */
994 	mtrr_bp_init();
995 	if (mtrr_trim_uncached_memory(max_pfn))
996 		max_pfn = e820__end_of_ram_pfn();
997 
998 	max_possible_pfn = max_pfn;
999 
1000 	/*
1001 	 * This call is required when the CPU does not support PAT. If
1002 	 * mtrr_bp_init() invoked it already via pat_init() the call has no
1003 	 * effect.
1004 	 */
1005 	init_cache_modes();
1006 
1007 	/*
1008 	 * Define random base addresses for memory sections after max_pfn is
1009 	 * defined and before each memory section base is used.
1010 	 */
1011 	kernel_randomize_memory();
1012 
1013 #ifdef CONFIG_X86_32
1014 	/* max_low_pfn get updated here */
1015 	find_low_pfn_range();
1016 #else
1017 	check_x2apic();
1018 
1019 	/* How many end-of-memory variables you have, grandma! */
1020 	/* need this before calling reserve_initrd */
1021 	if (max_pfn > (1UL<<(32 - PAGE_SHIFT)))
1022 		max_low_pfn = e820__end_of_low_ram_pfn();
1023 	else
1024 		max_low_pfn = max_pfn;
1025 
1026 	high_memory = (void *)__va(max_pfn * PAGE_SIZE - 1) + 1;
1027 #endif
1028 
1029 	/*
1030 	 * Find and reserve possible boot-time SMP configuration:
1031 	 */
1032 	find_smp_config();
1033 
1034 	reserve_ibft_region();
1035 
1036 	early_alloc_pgt_buf();
1037 
1038 	/*
1039 	 * Need to conclude brk, before e820__memblock_setup()
1040 	 *  it could use memblock_find_in_range, could overlap with
1041 	 *  brk area.
1042 	 */
1043 	reserve_brk();
1044 
1045 	cleanup_highmap();
1046 
1047 	memblock_set_current_limit(ISA_END_ADDRESS);
1048 	e820__memblock_setup();
1049 
1050 	/*
1051 	 * Needs to run after memblock setup because it needs the physical
1052 	 * memory size.
1053 	 */
1054 	sev_setup_arch();
1055 
1056 	reserve_bios_regions();
1057 
1058 	efi_fake_memmap();
1059 	efi_find_mirror();
1060 	efi_esrt_init();
1061 	efi_mokvar_table_init();
1062 
1063 	/*
1064 	 * The EFI specification says that boot service code won't be
1065 	 * called after ExitBootServices(). This is, in fact, a lie.
1066 	 */
1067 	efi_reserve_boot_services();
1068 
1069 	/* preallocate 4k for mptable mpc */
1070 	e820__memblock_alloc_reserved_mpc_new();
1071 
1072 #ifdef CONFIG_X86_CHECK_BIOS_CORRUPTION
1073 	setup_bios_corruption_check();
1074 #endif
1075 
1076 #ifdef CONFIG_X86_32
1077 	printk(KERN_DEBUG "initial memory mapped: [mem 0x00000000-%#010lx]\n",
1078 			(max_pfn_mapped<<PAGE_SHIFT) - 1);
1079 #endif
1080 
1081 	reserve_real_mode();
1082 
1083 	trim_platform_memory_ranges();
1084 	trim_low_memory_range();
1085 
1086 	init_mem_mapping();
1087 
1088 	idt_setup_early_pf();
1089 
1090 	/*
1091 	 * Update mmu_cr4_features (and, indirectly, trampoline_cr4_features)
1092 	 * with the current CR4 value.  This may not be necessary, but
1093 	 * auditing all the early-boot CR4 manipulation would be needed to
1094 	 * rule it out.
1095 	 *
1096 	 * Mask off features that don't work outside long mode (just
1097 	 * PCIDE for now).
1098 	 */
1099 	mmu_cr4_features = __read_cr4() & ~X86_CR4_PCIDE;
1100 
1101 	memblock_set_current_limit(get_max_mapped());
1102 
1103 	/*
1104 	 * NOTE: On x86-32, only from this point on, fixmaps are ready for use.
1105 	 */
1106 
1107 #ifdef CONFIG_PROVIDE_OHCI1394_DMA_INIT
1108 	if (init_ohci1394_dma_early)
1109 		init_ohci1394_dma_on_all_controllers();
1110 #endif
1111 	/* Allocate bigger log buffer */
1112 	setup_log_buf(1);
1113 
1114 	if (efi_enabled(EFI_BOOT)) {
1115 		switch (boot_params.secure_boot) {
1116 		case efi_secureboot_mode_disabled:
1117 			pr_info("Secure boot disabled\n");
1118 			break;
1119 		case efi_secureboot_mode_enabled:
1120 			pr_info("Secure boot enabled\n");
1121 			break;
1122 		default:
1123 			pr_info("Secure boot could not be determined\n");
1124 			break;
1125 		}
1126 	}
1127 
1128 	reserve_initrd();
1129 
1130 	acpi_table_upgrade();
1131 
1132 	vsmp_init();
1133 
1134 	io_delay_init();
1135 
1136 	early_platform_quirks();
1137 
1138 	/*
1139 	 * Parse the ACPI tables for possible boot-time SMP configuration.
1140 	 */
1141 	acpi_boot_table_init();
1142 
1143 	early_acpi_boot_init();
1144 
1145 	initmem_init();
1146 	dma_contiguous_reserve(max_pfn_mapped << PAGE_SHIFT);
1147 
1148 	if (boot_cpu_has(X86_FEATURE_GBPAGES))
1149 		hugetlb_cma_reserve(PUD_SHIFT - PAGE_SHIFT);
1150 
1151 	/*
1152 	 * Reserve memory for crash kernel after SRAT is parsed so that it
1153 	 * won't consume hotpluggable memory.
1154 	 */
1155 	reserve_crashkernel();
1156 
1157 	memblock_find_dma_reserve();
1158 
1159 	if (!early_xdbc_setup_hardware())
1160 		early_xdbc_register_console();
1161 
1162 	x86_init.paging.pagetable_init();
1163 
1164 	kasan_init();
1165 
1166 	/*
1167 	 * Sync back kernel address range.
1168 	 *
1169 	 * FIXME: Can the later sync in setup_cpu_entry_areas() replace
1170 	 * this call?
1171 	 */
1172 	sync_initial_page_table();
1173 
1174 	tboot_probe();
1175 
1176 	map_vsyscall();
1177 
1178 	generic_apic_probe();
1179 
1180 	early_quirks();
1181 
1182 	/*
1183 	 * Read APIC and some other early information from ACPI tables.
1184 	 */
1185 	acpi_boot_init();
1186 	sfi_init();
1187 	x86_dtb_init();
1188 
1189 	/*
1190 	 * get boot-time SMP configuration:
1191 	 */
1192 	get_smp_config();
1193 
1194 	/*
1195 	 * Systems w/o ACPI and mptables might not have it mapped the local
1196 	 * APIC yet, but prefill_possible_map() might need to access it.
1197 	 */
1198 	init_apic_mappings();
1199 
1200 	prefill_possible_map();
1201 
1202 	init_cpu_to_node();
1203 	init_gi_nodes();
1204 
1205 	io_apic_init_mappings();
1206 
1207 	x86_init.hyper.guest_late_init();
1208 
1209 	e820__reserve_resources();
1210 	e820__register_nosave_regions(max_pfn);
1211 
1212 	x86_init.resources.reserve_resources();
1213 
1214 	e820__setup_pci_gap();
1215 
1216 #ifdef CONFIG_VT
1217 #if defined(CONFIG_VGA_CONSOLE)
1218 	if (!efi_enabled(EFI_BOOT) || (efi_mem_type(0xa0000) != EFI_CONVENTIONAL_MEMORY))
1219 		conswitchp = &vga_con;
1220 #endif
1221 #endif
1222 	x86_init.oem.banner();
1223 
1224 	x86_init.timers.wallclock_init();
1225 
1226 	mcheck_init();
1227 
1228 	register_refined_jiffies(CLOCK_TICK_RATE);
1229 
1230 #ifdef CONFIG_EFI
1231 	if (efi_enabled(EFI_BOOT))
1232 		efi_apply_memmap_quirks();
1233 #endif
1234 
1235 	unwind_init();
1236 }
1237 
1238 #ifdef CONFIG_X86_32
1239 
1240 static struct resource video_ram_resource = {
1241 	.name	= "Video RAM area",
1242 	.start	= 0xa0000,
1243 	.end	= 0xbffff,
1244 	.flags	= IORESOURCE_BUSY | IORESOURCE_MEM
1245 };
1246 
1247 void __init i386_reserve_resources(void)
1248 {
1249 	request_resource(&iomem_resource, &video_ram_resource);
1250 	reserve_standard_io_resources();
1251 }
1252 
1253 #endif /* CONFIG_X86_32 */
1254 
1255 static struct notifier_block kernel_offset_notifier = {
1256 	.notifier_call = dump_kernel_offset
1257 };
1258 
1259 static int __init register_kernel_offset_dumper(void)
1260 {
1261 	atomic_notifier_chain_register(&panic_notifier_list,
1262 					&kernel_offset_notifier);
1263 	return 0;
1264 }
1265 __initcall(register_kernel_offset_dumper);
1266