xref: /openbmc/linux/arch/x86/kernel/setup.c (revision 53a2a90d)
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/acpi.h>
9 #include <linux/console.h>
10 #include <linux/crash_dump.h>
11 #include <linux/dma-map-ops.h>
12 #include <linux/dmi.h>
13 #include <linux/efi.h>
14 #include <linux/init_ohci1394_dma.h>
15 #include <linux/initrd.h>
16 #include <linux/iscsi_ibft.h>
17 #include <linux/memblock.h>
18 #include <linux/panic_notifier.h>
19 #include <linux/pci.h>
20 #include <linux/root_dev.h>
21 #include <linux/hugetlb.h>
22 #include <linux/tboot.h>
23 #include <linux/usb/xhci-dbgp.h>
24 #include <linux/static_call.h>
25 #include <linux/swiotlb.h>
26 
27 #include <uapi/linux/mount.h>
28 
29 #include <xen/xen.h>
30 
31 #include <asm/apic.h>
32 #include <asm/numa.h>
33 #include <asm/bios_ebda.h>
34 #include <asm/bugs.h>
35 #include <asm/cpu.h>
36 #include <asm/efi.h>
37 #include <asm/gart.h>
38 #include <asm/hypervisor.h>
39 #include <asm/io_apic.h>
40 #include <asm/kasan.h>
41 #include <asm/kaslr.h>
42 #include <asm/mce.h>
43 #include <asm/memtype.h>
44 #include <asm/mtrr.h>
45 #include <asm/realmode.h>
46 #include <asm/olpc_ofw.h>
47 #include <asm/pci-direct.h>
48 #include <asm/prom.h>
49 #include <asm/proto.h>
50 #include <asm/thermal.h>
51 #include <asm/unwind.h>
52 #include <asm/vsyscall.h>
53 #include <linux/vmalloc.h>
54 
55 /*
56  * max_low_pfn_mapped: highest directly mapped pfn < 4 GB
57  * max_pfn_mapped:     highest directly mapped pfn > 4 GB
58  *
59  * The direct mapping only covers E820_TYPE_RAM regions, so the ranges and gaps are
60  * represented by pfn_mapped[].
61  */
62 unsigned long max_low_pfn_mapped;
63 unsigned long max_pfn_mapped;
64 
65 #ifdef CONFIG_DMI
66 RESERVE_BRK(dmi_alloc, 65536);
67 #endif
68 
69 
70 unsigned long _brk_start = (unsigned long)__brk_base;
71 unsigned long _brk_end   = (unsigned long)__brk_base;
72 
73 struct boot_params boot_params;
74 
75 /*
76  * These are the four main kernel memory regions, we put them into
77  * the resource tree so that kdump tools and other debugging tools
78  * recover it:
79  */
80 
81 static struct resource rodata_resource = {
82 	.name	= "Kernel rodata",
83 	.start	= 0,
84 	.end	= 0,
85 	.flags	= IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM
86 };
87 
88 static struct resource data_resource = {
89 	.name	= "Kernel data",
90 	.start	= 0,
91 	.end	= 0,
92 	.flags	= IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM
93 };
94 
95 static struct resource code_resource = {
96 	.name	= "Kernel code",
97 	.start	= 0,
98 	.end	= 0,
99 	.flags	= IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM
100 };
101 
102 static struct resource bss_resource = {
103 	.name	= "Kernel bss",
104 	.start	= 0,
105 	.end	= 0,
106 	.flags	= IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM
107 };
108 
109 
110 #ifdef CONFIG_X86_32
111 /* CPU data as detected by the assembly code in head_32.S */
112 struct cpuinfo_x86 new_cpu_data;
113 
114 /* Common CPU data for all CPUs */
115 struct cpuinfo_x86 boot_cpu_data __read_mostly;
116 EXPORT_SYMBOL(boot_cpu_data);
117 
118 unsigned int def_to_bigsmp;
119 
120 struct apm_info apm_info;
121 EXPORT_SYMBOL(apm_info);
122 
123 #if defined(CONFIG_X86_SPEEDSTEP_SMI) || \
124 	defined(CONFIG_X86_SPEEDSTEP_SMI_MODULE)
125 struct ist_info ist_info;
126 EXPORT_SYMBOL(ist_info);
127 #else
128 struct ist_info ist_info;
129 #endif
130 
131 #else
132 struct cpuinfo_x86 boot_cpu_data __read_mostly;
133 EXPORT_SYMBOL(boot_cpu_data);
134 #endif
135 
136 
137 #if !defined(CONFIG_X86_PAE) || defined(CONFIG_X86_64)
138 __visible unsigned long mmu_cr4_features __ro_after_init;
139 #else
140 __visible unsigned long mmu_cr4_features __ro_after_init = X86_CR4_PAE;
141 #endif
142 
143 /* Boot loader ID and version as integers, for the benefit of proc_dointvec */
144 int bootloader_type, bootloader_version;
145 
146 /*
147  * Setup options
148  */
149 struct screen_info screen_info;
150 EXPORT_SYMBOL(screen_info);
151 struct edid_info edid_info;
152 EXPORT_SYMBOL_GPL(edid_info);
153 
154 extern int root_mountflags;
155 
156 unsigned long saved_video_mode;
157 
158 #define RAMDISK_IMAGE_START_MASK	0x07FF
159 #define RAMDISK_PROMPT_FLAG		0x8000
160 #define RAMDISK_LOAD_FLAG		0x4000
161 
162 static char __initdata command_line[COMMAND_LINE_SIZE];
163 #ifdef CONFIG_CMDLINE_BOOL
164 static char __initdata builtin_cmdline[COMMAND_LINE_SIZE] = CONFIG_CMDLINE;
165 #endif
166 
167 #if defined(CONFIG_EDD) || defined(CONFIG_EDD_MODULE)
168 struct edd edd;
169 #ifdef CONFIG_EDD_MODULE
170 EXPORT_SYMBOL(edd);
171 #endif
172 /**
173  * copy_edd() - Copy the BIOS EDD information
174  *              from boot_params into a safe place.
175  *
176  */
177 static inline void __init copy_edd(void)
178 {
179      memcpy(edd.mbr_signature, boot_params.edd_mbr_sig_buffer,
180 	    sizeof(edd.mbr_signature));
181      memcpy(edd.edd_info, boot_params.eddbuf, sizeof(edd.edd_info));
182      edd.mbr_signature_nr = boot_params.edd_mbr_sig_buf_entries;
183      edd.edd_info_nr = boot_params.eddbuf_entries;
184 }
185 #else
186 static inline void __init copy_edd(void)
187 {
188 }
189 #endif
190 
191 void * __init extend_brk(size_t size, size_t align)
192 {
193 	size_t mask = align - 1;
194 	void *ret;
195 
196 	BUG_ON(_brk_start == 0);
197 	BUG_ON(align & mask);
198 
199 	_brk_end = (_brk_end + mask) & ~mask;
200 	BUG_ON((char *)(_brk_end + size) > __brk_limit);
201 
202 	ret = (void *)_brk_end;
203 	_brk_end += size;
204 
205 	memset(ret, 0, size);
206 
207 	return ret;
208 }
209 
210 #ifdef CONFIG_X86_32
211 static void __init cleanup_highmap(void)
212 {
213 }
214 #endif
215 
216 static void __init reserve_brk(void)
217 {
218 	if (_brk_end > _brk_start)
219 		memblock_reserve(__pa_symbol(_brk_start),
220 				 _brk_end - _brk_start);
221 
222 	/* Mark brk area as locked down and no longer taking any
223 	   new allocations */
224 	_brk_start = 0;
225 }
226 
227 u64 relocated_ramdisk;
228 
229 #ifdef CONFIG_BLK_DEV_INITRD
230 
231 static u64 __init get_ramdisk_image(void)
232 {
233 	u64 ramdisk_image = boot_params.hdr.ramdisk_image;
234 
235 	ramdisk_image |= (u64)boot_params.ext_ramdisk_image << 32;
236 
237 	if (ramdisk_image == 0)
238 		ramdisk_image = phys_initrd_start;
239 
240 	return ramdisk_image;
241 }
242 static u64 __init get_ramdisk_size(void)
243 {
244 	u64 ramdisk_size = boot_params.hdr.ramdisk_size;
245 
246 	ramdisk_size |= (u64)boot_params.ext_ramdisk_size << 32;
247 
248 	if (ramdisk_size == 0)
249 		ramdisk_size = phys_initrd_size;
250 
251 	return ramdisk_size;
252 }
253 
254 static void __init relocate_initrd(void)
255 {
256 	/* Assume only end is not page aligned */
257 	u64 ramdisk_image = get_ramdisk_image();
258 	u64 ramdisk_size  = get_ramdisk_size();
259 	u64 area_size     = PAGE_ALIGN(ramdisk_size);
260 
261 	/* We need to move the initrd down into directly mapped mem */
262 	relocated_ramdisk = memblock_phys_alloc_range(area_size, PAGE_SIZE, 0,
263 						      PFN_PHYS(max_pfn_mapped));
264 	if (!relocated_ramdisk)
265 		panic("Cannot find place for new RAMDISK of size %lld\n",
266 		      ramdisk_size);
267 
268 	initrd_start = relocated_ramdisk + PAGE_OFFSET;
269 	initrd_end   = initrd_start + ramdisk_size;
270 	printk(KERN_INFO "Allocated new RAMDISK: [mem %#010llx-%#010llx]\n",
271 	       relocated_ramdisk, relocated_ramdisk + ramdisk_size - 1);
272 
273 	copy_from_early_mem((void *)initrd_start, ramdisk_image, ramdisk_size);
274 
275 	printk(KERN_INFO "Move RAMDISK from [mem %#010llx-%#010llx] to"
276 		" [mem %#010llx-%#010llx]\n",
277 		ramdisk_image, ramdisk_image + ramdisk_size - 1,
278 		relocated_ramdisk, relocated_ramdisk + ramdisk_size - 1);
279 }
280 
281 static void __init early_reserve_initrd(void)
282 {
283 	/* Assume only end is not page aligned */
284 	u64 ramdisk_image = get_ramdisk_image();
285 	u64 ramdisk_size  = get_ramdisk_size();
286 	u64 ramdisk_end   = PAGE_ALIGN(ramdisk_image + ramdisk_size);
287 
288 	if (!boot_params.hdr.type_of_loader ||
289 	    !ramdisk_image || !ramdisk_size)
290 		return;		/* No initrd provided by bootloader */
291 
292 	memblock_reserve(ramdisk_image, ramdisk_end - ramdisk_image);
293 }
294 
295 static void __init reserve_initrd(void)
296 {
297 	/* Assume only end is not page aligned */
298 	u64 ramdisk_image = get_ramdisk_image();
299 	u64 ramdisk_size  = get_ramdisk_size();
300 	u64 ramdisk_end   = PAGE_ALIGN(ramdisk_image + ramdisk_size);
301 
302 	if (!boot_params.hdr.type_of_loader ||
303 	    !ramdisk_image || !ramdisk_size)
304 		return;		/* No initrd provided by bootloader */
305 
306 	initrd_start = 0;
307 
308 	printk(KERN_INFO "RAMDISK: [mem %#010llx-%#010llx]\n", ramdisk_image,
309 			ramdisk_end - 1);
310 
311 	if (pfn_range_is_mapped(PFN_DOWN(ramdisk_image),
312 				PFN_DOWN(ramdisk_end))) {
313 		/* All are mapped, easy case */
314 		initrd_start = ramdisk_image + PAGE_OFFSET;
315 		initrd_end = initrd_start + ramdisk_size;
316 		return;
317 	}
318 
319 	relocate_initrd();
320 
321 	memblock_phys_free(ramdisk_image, ramdisk_end - ramdisk_image);
322 }
323 
324 #else
325 static void __init early_reserve_initrd(void)
326 {
327 }
328 static void __init reserve_initrd(void)
329 {
330 }
331 #endif /* CONFIG_BLK_DEV_INITRD */
332 
333 static void __init parse_setup_data(void)
334 {
335 	struct setup_data *data;
336 	u64 pa_data, pa_next;
337 
338 	pa_data = boot_params.hdr.setup_data;
339 	while (pa_data) {
340 		u32 data_len, data_type;
341 
342 		data = early_memremap(pa_data, sizeof(*data));
343 		data_len = data->len + sizeof(struct setup_data);
344 		data_type = data->type;
345 		pa_next = data->next;
346 		early_memunmap(data, sizeof(*data));
347 
348 		switch (data_type) {
349 		case SETUP_E820_EXT:
350 			e820__memory_setup_extended(pa_data, data_len);
351 			break;
352 		case SETUP_DTB:
353 			add_dtb(pa_data);
354 			break;
355 		case SETUP_EFI:
356 			parse_efi_setup(pa_data, data_len);
357 			break;
358 		default:
359 			break;
360 		}
361 		pa_data = pa_next;
362 	}
363 }
364 
365 static void __init memblock_x86_reserve_range_setup_data(void)
366 {
367 	struct setup_indirect *indirect;
368 	struct setup_data *data;
369 	u64 pa_data, pa_next;
370 	u32 len;
371 
372 	pa_data = boot_params.hdr.setup_data;
373 	while (pa_data) {
374 		data = early_memremap(pa_data, sizeof(*data));
375 		if (!data) {
376 			pr_warn("setup: failed to memremap setup_data entry\n");
377 			return;
378 		}
379 
380 		len = sizeof(*data);
381 		pa_next = data->next;
382 
383 		memblock_reserve(pa_data, sizeof(*data) + data->len);
384 
385 		if (data->type == SETUP_INDIRECT) {
386 			len += data->len;
387 			early_memunmap(data, sizeof(*data));
388 			data = early_memremap(pa_data, len);
389 			if (!data) {
390 				pr_warn("setup: failed to memremap indirect setup_data\n");
391 				return;
392 			}
393 
394 			indirect = (struct setup_indirect *)data->data;
395 
396 			if (indirect->type != SETUP_INDIRECT)
397 				memblock_reserve(indirect->addr, indirect->len);
398 		}
399 
400 		pa_data = pa_next;
401 		early_memunmap(data, len);
402 	}
403 }
404 
405 /*
406  * --------- Crashkernel reservation ------------------------------
407  */
408 
409 /* 16M alignment for crash kernel regions */
410 #define CRASH_ALIGN		SZ_16M
411 
412 /*
413  * Keep the crash kernel below this limit.
414  *
415  * Earlier 32-bits kernels would limit the kernel to the low 512 MB range
416  * due to mapping restrictions.
417  *
418  * 64-bit kdump kernels need to be restricted to be under 64 TB, which is
419  * the upper limit of system RAM in 4-level paging mode. Since the kdump
420  * jump could be from 5-level paging to 4-level paging, the jump will fail if
421  * the kernel is put above 64 TB, and during the 1st kernel bootup there's
422  * no good way to detect the paging mode of the target kernel which will be
423  * loaded for dumping.
424  */
425 #ifdef CONFIG_X86_32
426 # define CRASH_ADDR_LOW_MAX	SZ_512M
427 # define CRASH_ADDR_HIGH_MAX	SZ_512M
428 #else
429 # define CRASH_ADDR_LOW_MAX	SZ_4G
430 # define CRASH_ADDR_HIGH_MAX	SZ_64T
431 #endif
432 
433 static int __init reserve_crashkernel_low(void)
434 {
435 #ifdef CONFIG_X86_64
436 	unsigned long long base, low_base = 0, low_size = 0;
437 	unsigned long low_mem_limit;
438 	int ret;
439 
440 	low_mem_limit = min(memblock_phys_mem_size(), CRASH_ADDR_LOW_MAX);
441 
442 	/* crashkernel=Y,low */
443 	ret = parse_crashkernel_low(boot_command_line, low_mem_limit, &low_size, &base);
444 	if (ret) {
445 		/*
446 		 * two parts from kernel/dma/swiotlb.c:
447 		 * -swiotlb size: user-specified with swiotlb= or default.
448 		 *
449 		 * -swiotlb overflow buffer: now hardcoded to 32k. We round it
450 		 * to 8M for other buffers that may need to stay low too. Also
451 		 * make sure we allocate enough extra low memory so that we
452 		 * don't run out of DMA buffers for 32-bit devices.
453 		 */
454 		low_size = max(swiotlb_size_or_default() + (8UL << 20), 256UL << 20);
455 	} else {
456 		/* passed with crashkernel=0,low ? */
457 		if (!low_size)
458 			return 0;
459 	}
460 
461 	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, 0, CRASH_ADDR_LOW_MAX);
462 	if (!low_base) {
463 		pr_err("Cannot reserve %ldMB crashkernel low memory, please try smaller size.\n",
464 		       (unsigned long)(low_size >> 20));
465 		return -ENOMEM;
466 	}
467 
468 	pr_info("Reserving %ldMB of low memory at %ldMB for crashkernel (low RAM limit: %ldMB)\n",
469 		(unsigned long)(low_size >> 20),
470 		(unsigned long)(low_base >> 20),
471 		(unsigned long)(low_mem_limit >> 20));
472 
473 	crashk_low_res.start = low_base;
474 	crashk_low_res.end   = low_base + low_size - 1;
475 	insert_resource(&iomem_resource, &crashk_low_res);
476 #endif
477 	return 0;
478 }
479 
480 static void __init reserve_crashkernel(void)
481 {
482 	unsigned long long crash_size, crash_base, total_mem;
483 	bool high = false;
484 	int ret;
485 
486 	if (!IS_ENABLED(CONFIG_KEXEC_CORE))
487 		return;
488 
489 	total_mem = memblock_phys_mem_size();
490 
491 	/* crashkernel=XM */
492 	ret = parse_crashkernel(boot_command_line, total_mem, &crash_size, &crash_base);
493 	if (ret != 0 || crash_size <= 0) {
494 		/* crashkernel=X,high */
495 		ret = parse_crashkernel_high(boot_command_line, total_mem,
496 					     &crash_size, &crash_base);
497 		if (ret != 0 || crash_size <= 0)
498 			return;
499 		high = true;
500 	}
501 
502 	if (xen_pv_domain()) {
503 		pr_info("Ignoring crashkernel for a Xen PV domain\n");
504 		return;
505 	}
506 
507 	/* 0 means: find the address automatically */
508 	if (!crash_base) {
509 		/*
510 		 * Set CRASH_ADDR_LOW_MAX upper bound for crash memory,
511 		 * crashkernel=x,high reserves memory over 4G, also allocates
512 		 * 256M extra low memory for DMA buffers and swiotlb.
513 		 * But the extra memory is not required for all machines.
514 		 * So try low memory first and fall back to high memory
515 		 * unless "crashkernel=size[KMG],high" is specified.
516 		 */
517 		if (!high)
518 			crash_base = memblock_phys_alloc_range(crash_size,
519 						CRASH_ALIGN, CRASH_ALIGN,
520 						CRASH_ADDR_LOW_MAX);
521 		if (!crash_base)
522 			crash_base = memblock_phys_alloc_range(crash_size,
523 						CRASH_ALIGN, CRASH_ALIGN,
524 						CRASH_ADDR_HIGH_MAX);
525 		if (!crash_base) {
526 			pr_info("crashkernel reservation failed - No suitable area found.\n");
527 			return;
528 		}
529 	} else {
530 		unsigned long long start;
531 
532 		start = memblock_phys_alloc_range(crash_size, SZ_1M, crash_base,
533 						  crash_base + crash_size);
534 		if (start != crash_base) {
535 			pr_info("crashkernel reservation failed - memory is in use.\n");
536 			return;
537 		}
538 	}
539 
540 	if (crash_base >= (1ULL << 32) && reserve_crashkernel_low()) {
541 		memblock_phys_free(crash_base, crash_size);
542 		return;
543 	}
544 
545 	pr_info("Reserving %ldMB of memory at %ldMB for crashkernel (System RAM: %ldMB)\n",
546 		(unsigned long)(crash_size >> 20),
547 		(unsigned long)(crash_base >> 20),
548 		(unsigned long)(total_mem >> 20));
549 
550 	crashk_res.start = crash_base;
551 	crashk_res.end   = crash_base + crash_size - 1;
552 	insert_resource(&iomem_resource, &crashk_res);
553 }
554 
555 static struct resource standard_io_resources[] = {
556 	{ .name = "dma1", .start = 0x00, .end = 0x1f,
557 		.flags = IORESOURCE_BUSY | IORESOURCE_IO },
558 	{ .name = "pic1", .start = 0x20, .end = 0x21,
559 		.flags = IORESOURCE_BUSY | IORESOURCE_IO },
560 	{ .name = "timer0", .start = 0x40, .end = 0x43,
561 		.flags = IORESOURCE_BUSY | IORESOURCE_IO },
562 	{ .name = "timer1", .start = 0x50, .end = 0x53,
563 		.flags = IORESOURCE_BUSY | IORESOURCE_IO },
564 	{ .name = "keyboard", .start = 0x60, .end = 0x60,
565 		.flags = IORESOURCE_BUSY | IORESOURCE_IO },
566 	{ .name = "keyboard", .start = 0x64, .end = 0x64,
567 		.flags = IORESOURCE_BUSY | IORESOURCE_IO },
568 	{ .name = "dma page reg", .start = 0x80, .end = 0x8f,
569 		.flags = IORESOURCE_BUSY | IORESOURCE_IO },
570 	{ .name = "pic2", .start = 0xa0, .end = 0xa1,
571 		.flags = IORESOURCE_BUSY | IORESOURCE_IO },
572 	{ .name = "dma2", .start = 0xc0, .end = 0xdf,
573 		.flags = IORESOURCE_BUSY | IORESOURCE_IO },
574 	{ .name = "fpu", .start = 0xf0, .end = 0xff,
575 		.flags = IORESOURCE_BUSY | IORESOURCE_IO }
576 };
577 
578 void __init reserve_standard_io_resources(void)
579 {
580 	int i;
581 
582 	/* request I/O space for devices used on all i[345]86 PCs */
583 	for (i = 0; i < ARRAY_SIZE(standard_io_resources); i++)
584 		request_resource(&ioport_resource, &standard_io_resources[i]);
585 
586 }
587 
588 static bool __init snb_gfx_workaround_needed(void)
589 {
590 #ifdef CONFIG_PCI
591 	int i;
592 	u16 vendor, devid;
593 	static const __initconst u16 snb_ids[] = {
594 		0x0102,
595 		0x0112,
596 		0x0122,
597 		0x0106,
598 		0x0116,
599 		0x0126,
600 		0x010a,
601 	};
602 
603 	/* Assume no if something weird is going on with PCI */
604 	if (!early_pci_allowed())
605 		return false;
606 
607 	vendor = read_pci_config_16(0, 2, 0, PCI_VENDOR_ID);
608 	if (vendor != 0x8086)
609 		return false;
610 
611 	devid = read_pci_config_16(0, 2, 0, PCI_DEVICE_ID);
612 	for (i = 0; i < ARRAY_SIZE(snb_ids); i++)
613 		if (devid == snb_ids[i])
614 			return true;
615 #endif
616 
617 	return false;
618 }
619 
620 /*
621  * Sandy Bridge graphics has trouble with certain ranges, exclude
622  * them from allocation.
623  */
624 static void __init trim_snb_memory(void)
625 {
626 	static const __initconst unsigned long bad_pages[] = {
627 		0x20050000,
628 		0x20110000,
629 		0x20130000,
630 		0x20138000,
631 		0x40004000,
632 	};
633 	int i;
634 
635 	if (!snb_gfx_workaround_needed())
636 		return;
637 
638 	printk(KERN_DEBUG "reserving inaccessible SNB gfx pages\n");
639 
640 	/*
641 	 * SandyBridge integrated graphics devices have a bug that prevents
642 	 * them from accessing certain memory ranges, namely anything below
643 	 * 1M and in the pages listed in bad_pages[] above.
644 	 *
645 	 * To avoid these pages being ever accessed by SNB gfx devices reserve
646 	 * bad_pages that have not already been reserved at boot time.
647 	 * All memory below the 1 MB mark is anyway reserved later during
648 	 * setup_arch(), so there is no need to reserve it here.
649 	 */
650 
651 	for (i = 0; i < ARRAY_SIZE(bad_pages); i++) {
652 		if (memblock_reserve(bad_pages[i], PAGE_SIZE))
653 			printk(KERN_WARNING "failed to reserve 0x%08lx\n",
654 			       bad_pages[i]);
655 	}
656 }
657 
658 static void __init trim_bios_range(void)
659 {
660 	/*
661 	 * A special case is the first 4Kb of memory;
662 	 * This is a BIOS owned area, not kernel ram, but generally
663 	 * not listed as such in the E820 table.
664 	 *
665 	 * This typically reserves additional memory (64KiB by default)
666 	 * since some BIOSes are known to corrupt low memory.  See the
667 	 * Kconfig help text for X86_RESERVE_LOW.
668 	 */
669 	e820__range_update(0, PAGE_SIZE, E820_TYPE_RAM, E820_TYPE_RESERVED);
670 
671 	/*
672 	 * special case: Some BIOSes report the PC BIOS
673 	 * area (640Kb -> 1Mb) as RAM even though it is not.
674 	 * take them out.
675 	 */
676 	e820__range_remove(BIOS_BEGIN, BIOS_END - BIOS_BEGIN, E820_TYPE_RAM, 1);
677 
678 	e820__update_table(e820_table);
679 }
680 
681 /* called before trim_bios_range() to spare extra sanitize */
682 static void __init e820_add_kernel_range(void)
683 {
684 	u64 start = __pa_symbol(_text);
685 	u64 size = __pa_symbol(_end) - start;
686 
687 	/*
688 	 * Complain if .text .data and .bss are not marked as E820_TYPE_RAM and
689 	 * attempt to fix it by adding the range. We may have a confused BIOS,
690 	 * or the user may have used memmap=exactmap or memmap=xxM$yyM to
691 	 * exclude kernel range. If we really are running on top non-RAM,
692 	 * we will crash later anyways.
693 	 */
694 	if (e820__mapped_all(start, start + size, E820_TYPE_RAM))
695 		return;
696 
697 	pr_warn(".text .data .bss are not marked as E820_TYPE_RAM!\n");
698 	e820__range_remove(start, size, E820_TYPE_RAM, 0);
699 	e820__range_add(start, size, E820_TYPE_RAM);
700 }
701 
702 static void __init early_reserve_memory(void)
703 {
704 	/*
705 	 * Reserve the memory occupied by the kernel between _text and
706 	 * __end_of_kernel_reserve symbols. Any kernel sections after the
707 	 * __end_of_kernel_reserve symbol must be explicitly reserved with a
708 	 * separate memblock_reserve() or they will be discarded.
709 	 */
710 	memblock_reserve(__pa_symbol(_text),
711 			 (unsigned long)__end_of_kernel_reserve - (unsigned long)_text);
712 
713 	/*
714 	 * The first 4Kb of memory is a BIOS owned area, but generally it is
715 	 * not listed as such in the E820 table.
716 	 *
717 	 * Reserve the first 64K of memory since some BIOSes are known to
718 	 * corrupt low memory. After the real mode trampoline is allocated the
719 	 * rest of the memory below 640k is reserved.
720 	 *
721 	 * In addition, make sure page 0 is always reserved because on
722 	 * systems with L1TF its contents can be leaked to user processes.
723 	 */
724 	memblock_reserve(0, SZ_64K);
725 
726 	early_reserve_initrd();
727 
728 	memblock_x86_reserve_range_setup_data();
729 
730 	reserve_ibft_region();
731 	reserve_bios_regions();
732 	trim_snb_memory();
733 }
734 
735 /*
736  * Dump out kernel offset information on panic.
737  */
738 static int
739 dump_kernel_offset(struct notifier_block *self, unsigned long v, void *p)
740 {
741 	if (kaslr_enabled()) {
742 		pr_emerg("Kernel Offset: 0x%lx from 0x%lx (relocation range: 0x%lx-0x%lx)\n",
743 			 kaslr_offset(),
744 			 __START_KERNEL,
745 			 __START_KERNEL_map,
746 			 MODULES_VADDR-1);
747 	} else {
748 		pr_emerg("Kernel Offset: disabled\n");
749 	}
750 
751 	return 0;
752 }
753 
754 void x86_configure_nx(void)
755 {
756 	if (boot_cpu_has(X86_FEATURE_NX))
757 		__supported_pte_mask |= _PAGE_NX;
758 	else
759 		__supported_pte_mask &= ~_PAGE_NX;
760 }
761 
762 static void __init x86_report_nx(void)
763 {
764 	if (!boot_cpu_has(X86_FEATURE_NX)) {
765 		printk(KERN_NOTICE "Notice: NX (Execute Disable) protection "
766 		       "missing in CPU!\n");
767 	} else {
768 #if defined(CONFIG_X86_64) || defined(CONFIG_X86_PAE)
769 		printk(KERN_INFO "NX (Execute Disable) protection: active\n");
770 #else
771 		/* 32bit non-PAE kernel, NX cannot be used */
772 		printk(KERN_NOTICE "Notice: NX (Execute Disable) protection "
773 		       "cannot be enabled: non-PAE kernel!\n");
774 #endif
775 	}
776 }
777 
778 /*
779  * Determine if we were loaded by an EFI loader.  If so, then we have also been
780  * passed the efi memmap, systab, etc., so we should use these data structures
781  * for initialization.  Note, the efi init code path is determined by the
782  * global efi_enabled. This allows the same kernel image to be used on existing
783  * systems (with a traditional BIOS) as well as on EFI systems.
784  */
785 /*
786  * setup_arch - architecture-specific boot-time initializations
787  *
788  * Note: On x86_64, fixmaps are ready for use even before this is called.
789  */
790 
791 void __init setup_arch(char **cmdline_p)
792 {
793 #ifdef CONFIG_X86_32
794 	memcpy(&boot_cpu_data, &new_cpu_data, sizeof(new_cpu_data));
795 
796 	/*
797 	 * copy kernel address range established so far and switch
798 	 * to the proper swapper page table
799 	 */
800 	clone_pgd_range(swapper_pg_dir     + KERNEL_PGD_BOUNDARY,
801 			initial_page_table + KERNEL_PGD_BOUNDARY,
802 			KERNEL_PGD_PTRS);
803 
804 	load_cr3(swapper_pg_dir);
805 	/*
806 	 * Note: Quark X1000 CPUs advertise PGE incorrectly and require
807 	 * a cr3 based tlb flush, so the following __flush_tlb_all()
808 	 * will not flush anything because the CPU quirk which clears
809 	 * X86_FEATURE_PGE has not been invoked yet. Though due to the
810 	 * load_cr3() above the TLB has been flushed already. The
811 	 * quirk is invoked before subsequent calls to __flush_tlb_all()
812 	 * so proper operation is guaranteed.
813 	 */
814 	__flush_tlb_all();
815 #else
816 	printk(KERN_INFO "Command line: %s\n", boot_command_line);
817 	boot_cpu_data.x86_phys_bits = MAX_PHYSMEM_BITS;
818 #endif
819 
820 	/*
821 	 * If we have OLPC OFW, we might end up relocating the fixmap due to
822 	 * reserve_top(), so do this before touching the ioremap area.
823 	 */
824 	olpc_ofw_detect();
825 
826 	idt_setup_early_traps();
827 	early_cpu_init();
828 	jump_label_init();
829 	static_call_init();
830 	early_ioremap_init();
831 
832 	setup_olpc_ofw_pgd();
833 
834 	ROOT_DEV = old_decode_dev(boot_params.hdr.root_dev);
835 	screen_info = boot_params.screen_info;
836 	edid_info = boot_params.edid_info;
837 #ifdef CONFIG_X86_32
838 	apm_info.bios = boot_params.apm_bios_info;
839 	ist_info = boot_params.ist_info;
840 #endif
841 	saved_video_mode = boot_params.hdr.vid_mode;
842 	bootloader_type = boot_params.hdr.type_of_loader;
843 	if ((bootloader_type >> 4) == 0xe) {
844 		bootloader_type &= 0xf;
845 		bootloader_type |= (boot_params.hdr.ext_loader_type+0x10) << 4;
846 	}
847 	bootloader_version  = bootloader_type & 0xf;
848 	bootloader_version |= boot_params.hdr.ext_loader_ver << 4;
849 
850 #ifdef CONFIG_BLK_DEV_RAM
851 	rd_image_start = boot_params.hdr.ram_size & RAMDISK_IMAGE_START_MASK;
852 #endif
853 #ifdef CONFIG_EFI
854 	if (!strncmp((char *)&boot_params.efi_info.efi_loader_signature,
855 		     EFI32_LOADER_SIGNATURE, 4)) {
856 		set_bit(EFI_BOOT, &efi.flags);
857 	} else if (!strncmp((char *)&boot_params.efi_info.efi_loader_signature,
858 		     EFI64_LOADER_SIGNATURE, 4)) {
859 		set_bit(EFI_BOOT, &efi.flags);
860 		set_bit(EFI_64BIT, &efi.flags);
861 	}
862 #endif
863 
864 	x86_init.oem.arch_setup();
865 
866 	/*
867 	 * Do some memory reservations *before* memory is added to memblock, so
868 	 * memblock allocations won't overwrite it.
869 	 *
870 	 * After this point, everything still needed from the boot loader or
871 	 * firmware or kernel text should be early reserved or marked not RAM in
872 	 * e820. All other memory is free game.
873 	 *
874 	 * This call needs to happen before e820__memory_setup() which calls the
875 	 * xen_memory_setup() on Xen dom0 which relies on the fact that those
876 	 * early reservations have happened already.
877 	 */
878 	early_reserve_memory();
879 
880 	iomem_resource.end = (1ULL << boot_cpu_data.x86_phys_bits) - 1;
881 	e820__memory_setup();
882 	parse_setup_data();
883 
884 	copy_edd();
885 
886 	if (!boot_params.hdr.root_flags)
887 		root_mountflags &= ~MS_RDONLY;
888 	setup_initial_init_mm(_text, _etext, _edata, (void *)_brk_end);
889 
890 	code_resource.start = __pa_symbol(_text);
891 	code_resource.end = __pa_symbol(_etext)-1;
892 	rodata_resource.start = __pa_symbol(__start_rodata);
893 	rodata_resource.end = __pa_symbol(__end_rodata)-1;
894 	data_resource.start = __pa_symbol(_sdata);
895 	data_resource.end = __pa_symbol(_edata)-1;
896 	bss_resource.start = __pa_symbol(__bss_start);
897 	bss_resource.end = __pa_symbol(__bss_stop)-1;
898 
899 #ifdef CONFIG_CMDLINE_BOOL
900 #ifdef CONFIG_CMDLINE_OVERRIDE
901 	strscpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);
902 #else
903 	if (builtin_cmdline[0]) {
904 		/* append boot loader cmdline to builtin */
905 		strlcat(builtin_cmdline, " ", COMMAND_LINE_SIZE);
906 		strlcat(builtin_cmdline, boot_command_line, COMMAND_LINE_SIZE);
907 		strscpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);
908 	}
909 #endif
910 #endif
911 
912 	strscpy(command_line, boot_command_line, COMMAND_LINE_SIZE);
913 	*cmdline_p = command_line;
914 
915 	/*
916 	 * x86_configure_nx() is called before parse_early_param() to detect
917 	 * whether hardware doesn't support NX (so that the early EHCI debug
918 	 * console setup can safely call set_fixmap()).
919 	 */
920 	x86_configure_nx();
921 
922 	parse_early_param();
923 
924 	if (efi_enabled(EFI_BOOT))
925 		efi_memblock_x86_reserve_range();
926 
927 #ifdef CONFIG_MEMORY_HOTPLUG
928 	/*
929 	 * Memory used by the kernel cannot be hot-removed because Linux
930 	 * cannot migrate the kernel pages. When memory hotplug is
931 	 * enabled, we should prevent memblock from allocating memory
932 	 * for the kernel.
933 	 *
934 	 * ACPI SRAT records all hotpluggable memory ranges. But before
935 	 * SRAT is parsed, we don't know about it.
936 	 *
937 	 * The kernel image is loaded into memory at very early time. We
938 	 * cannot prevent this anyway. So on NUMA system, we set any
939 	 * node the kernel resides in as un-hotpluggable.
940 	 *
941 	 * Since on modern servers, one node could have double-digit
942 	 * gigabytes memory, we can assume the memory around the kernel
943 	 * image is also un-hotpluggable. So before SRAT is parsed, just
944 	 * allocate memory near the kernel image to try the best to keep
945 	 * the kernel away from hotpluggable memory.
946 	 */
947 	if (movable_node_is_enabled())
948 		memblock_set_bottom_up(true);
949 #endif
950 
951 	x86_report_nx();
952 
953 	if (acpi_mps_check()) {
954 #ifdef CONFIG_X86_LOCAL_APIC
955 		disable_apic = 1;
956 #endif
957 		setup_clear_cpu_cap(X86_FEATURE_APIC);
958 	}
959 
960 	e820__reserve_setup_data();
961 	e820__finish_early_params();
962 
963 	if (efi_enabled(EFI_BOOT))
964 		efi_init();
965 
966 	dmi_setup();
967 
968 	/*
969 	 * VMware detection requires dmi to be available, so this
970 	 * needs to be done after dmi_setup(), for the boot CPU.
971 	 */
972 	init_hypervisor_platform();
973 
974 	tsc_early_init();
975 	x86_init.resources.probe_roms();
976 
977 	/* after parse_early_param, so could debug it */
978 	insert_resource(&iomem_resource, &code_resource);
979 	insert_resource(&iomem_resource, &rodata_resource);
980 	insert_resource(&iomem_resource, &data_resource);
981 	insert_resource(&iomem_resource, &bss_resource);
982 
983 	e820_add_kernel_range();
984 	trim_bios_range();
985 #ifdef CONFIG_X86_32
986 	if (ppro_with_ram_bug()) {
987 		e820__range_update(0x70000000ULL, 0x40000ULL, E820_TYPE_RAM,
988 				  E820_TYPE_RESERVED);
989 		e820__update_table(e820_table);
990 		printk(KERN_INFO "fixed physical RAM map:\n");
991 		e820__print_table("bad_ppro");
992 	}
993 #else
994 	early_gart_iommu_check();
995 #endif
996 
997 	/*
998 	 * partially used pages are not usable - thus
999 	 * we are rounding upwards:
1000 	 */
1001 	max_pfn = e820__end_of_ram_pfn();
1002 
1003 	/* update e820 for memory not covered by WB MTRRs */
1004 	if (IS_ENABLED(CONFIG_MTRR))
1005 		mtrr_bp_init();
1006 	else
1007 		pat_disable("PAT support disabled because CONFIG_MTRR is disabled in the kernel.");
1008 
1009 	if (mtrr_trim_uncached_memory(max_pfn))
1010 		max_pfn = e820__end_of_ram_pfn();
1011 
1012 	max_possible_pfn = max_pfn;
1013 
1014 	/*
1015 	 * This call is required when the CPU does not support PAT. If
1016 	 * mtrr_bp_init() invoked it already via pat_init() the call has no
1017 	 * effect.
1018 	 */
1019 	init_cache_modes();
1020 
1021 	/*
1022 	 * Define random base addresses for memory sections after max_pfn is
1023 	 * defined and before each memory section base is used.
1024 	 */
1025 	kernel_randomize_memory();
1026 
1027 #ifdef CONFIG_X86_32
1028 	/* max_low_pfn get updated here */
1029 	find_low_pfn_range();
1030 #else
1031 	check_x2apic();
1032 
1033 	/* How many end-of-memory variables you have, grandma! */
1034 	/* need this before calling reserve_initrd */
1035 	if (max_pfn > (1UL<<(32 - PAGE_SHIFT)))
1036 		max_low_pfn = e820__end_of_low_ram_pfn();
1037 	else
1038 		max_low_pfn = max_pfn;
1039 
1040 	high_memory = (void *)__va(max_pfn * PAGE_SIZE - 1) + 1;
1041 #endif
1042 
1043 	/*
1044 	 * Find and reserve possible boot-time SMP configuration:
1045 	 */
1046 	find_smp_config();
1047 
1048 	early_alloc_pgt_buf();
1049 
1050 	/*
1051 	 * Need to conclude brk, before e820__memblock_setup()
1052 	 * it could use memblock_find_in_range, could overlap with
1053 	 * brk area.
1054 	 */
1055 	reserve_brk();
1056 
1057 	cleanup_highmap();
1058 
1059 	memblock_set_current_limit(ISA_END_ADDRESS);
1060 	e820__memblock_setup();
1061 
1062 	/*
1063 	 * Needs to run after memblock setup because it needs the physical
1064 	 * memory size.
1065 	 */
1066 	sev_setup_arch();
1067 
1068 	efi_fake_memmap();
1069 	efi_find_mirror();
1070 	efi_esrt_init();
1071 	efi_mokvar_table_init();
1072 
1073 	/*
1074 	 * The EFI specification says that boot service code won't be
1075 	 * called after ExitBootServices(). This is, in fact, a lie.
1076 	 */
1077 	efi_reserve_boot_services();
1078 
1079 	/* preallocate 4k for mptable mpc */
1080 	e820__memblock_alloc_reserved_mpc_new();
1081 
1082 #ifdef CONFIG_X86_CHECK_BIOS_CORRUPTION
1083 	setup_bios_corruption_check();
1084 #endif
1085 
1086 #ifdef CONFIG_X86_32
1087 	printk(KERN_DEBUG "initial memory mapped: [mem 0x00000000-%#010lx]\n",
1088 			(max_pfn_mapped<<PAGE_SHIFT) - 1);
1089 #endif
1090 
1091 	/*
1092 	 * Find free memory for the real mode trampoline and place it there. If
1093 	 * there is not enough free memory under 1M, on EFI-enabled systems
1094 	 * there will be additional attempt to reclaim the memory for the real
1095 	 * mode trampoline at efi_free_boot_services().
1096 	 *
1097 	 * Unconditionally reserve the entire first 1M of RAM because BIOSes
1098 	 * are known to corrupt low memory and several hundred kilobytes are not
1099 	 * worth complex detection what memory gets clobbered. Windows does the
1100 	 * same thing for very similar reasons.
1101 	 *
1102 	 * Moreover, on machines with SandyBridge graphics or in setups that use
1103 	 * crashkernel the entire 1M is reserved anyway.
1104 	 */
1105 	reserve_real_mode();
1106 
1107 	init_mem_mapping();
1108 
1109 	idt_setup_early_pf();
1110 
1111 	/*
1112 	 * Update mmu_cr4_features (and, indirectly, trampoline_cr4_features)
1113 	 * with the current CR4 value.  This may not be necessary, but
1114 	 * auditing all the early-boot CR4 manipulation would be needed to
1115 	 * rule it out.
1116 	 *
1117 	 * Mask off features that don't work outside long mode (just
1118 	 * PCIDE for now).
1119 	 */
1120 	mmu_cr4_features = __read_cr4() & ~X86_CR4_PCIDE;
1121 
1122 	memblock_set_current_limit(get_max_mapped());
1123 
1124 	/*
1125 	 * NOTE: On x86-32, only from this point on, fixmaps are ready for use.
1126 	 */
1127 
1128 #ifdef CONFIG_PROVIDE_OHCI1394_DMA_INIT
1129 	if (init_ohci1394_dma_early)
1130 		init_ohci1394_dma_on_all_controllers();
1131 #endif
1132 	/* Allocate bigger log buffer */
1133 	setup_log_buf(1);
1134 
1135 	if (efi_enabled(EFI_BOOT)) {
1136 		switch (boot_params.secure_boot) {
1137 		case efi_secureboot_mode_disabled:
1138 			pr_info("Secure boot disabled\n");
1139 			break;
1140 		case efi_secureboot_mode_enabled:
1141 			pr_info("Secure boot enabled\n");
1142 			break;
1143 		default:
1144 			pr_info("Secure boot could not be determined\n");
1145 			break;
1146 		}
1147 	}
1148 
1149 	reserve_initrd();
1150 
1151 	acpi_table_upgrade();
1152 	/* Look for ACPI tables and reserve memory occupied by them. */
1153 	acpi_boot_table_init();
1154 
1155 	vsmp_init();
1156 
1157 	io_delay_init();
1158 
1159 	early_platform_quirks();
1160 
1161 	early_acpi_boot_init();
1162 
1163 	initmem_init();
1164 	dma_contiguous_reserve(max_pfn_mapped << PAGE_SHIFT);
1165 
1166 	if (boot_cpu_has(X86_FEATURE_GBPAGES))
1167 		hugetlb_cma_reserve(PUD_SHIFT - PAGE_SHIFT);
1168 
1169 	/*
1170 	 * Reserve memory for crash kernel after SRAT is parsed so that it
1171 	 * won't consume hotpluggable memory.
1172 	 */
1173 	reserve_crashkernel();
1174 
1175 	memblock_find_dma_reserve();
1176 
1177 	if (!early_xdbc_setup_hardware())
1178 		early_xdbc_register_console();
1179 
1180 	x86_init.paging.pagetable_init();
1181 
1182 	kasan_init();
1183 
1184 	/*
1185 	 * Sync back kernel address range.
1186 	 *
1187 	 * FIXME: Can the later sync in setup_cpu_entry_areas() replace
1188 	 * this call?
1189 	 */
1190 	sync_initial_page_table();
1191 
1192 	tboot_probe();
1193 
1194 	map_vsyscall();
1195 
1196 	generic_apic_probe();
1197 
1198 	early_quirks();
1199 
1200 	/*
1201 	 * Read APIC and some other early information from ACPI tables.
1202 	 */
1203 	acpi_boot_init();
1204 	x86_dtb_init();
1205 
1206 	/*
1207 	 * get boot-time SMP configuration:
1208 	 */
1209 	get_smp_config();
1210 
1211 	/*
1212 	 * Systems w/o ACPI and mptables might not have it mapped the local
1213 	 * APIC yet, but prefill_possible_map() might need to access it.
1214 	 */
1215 	init_apic_mappings();
1216 
1217 	prefill_possible_map();
1218 
1219 	init_cpu_to_node();
1220 	init_gi_nodes();
1221 
1222 	io_apic_init_mappings();
1223 
1224 	x86_init.hyper.guest_late_init();
1225 
1226 	e820__reserve_resources();
1227 	e820__register_nosave_regions(max_pfn);
1228 
1229 	x86_init.resources.reserve_resources();
1230 
1231 	e820__setup_pci_gap();
1232 
1233 #ifdef CONFIG_VT
1234 #if defined(CONFIG_VGA_CONSOLE)
1235 	if (!efi_enabled(EFI_BOOT) || (efi_mem_type(0xa0000) != EFI_CONVENTIONAL_MEMORY))
1236 		conswitchp = &vga_con;
1237 #endif
1238 #endif
1239 	x86_init.oem.banner();
1240 
1241 	x86_init.timers.wallclock_init();
1242 
1243 	/*
1244 	 * This needs to run before setup_local_APIC() which soft-disables the
1245 	 * local APIC temporarily and that masks the thermal LVT interrupt,
1246 	 * leading to softlockups on machines which have configured SMI
1247 	 * interrupt delivery.
1248 	 */
1249 	therm_lvt_init();
1250 
1251 	mcheck_init();
1252 
1253 	register_refined_jiffies(CLOCK_TICK_RATE);
1254 
1255 #ifdef CONFIG_EFI
1256 	if (efi_enabled(EFI_BOOT))
1257 		efi_apply_memmap_quirks();
1258 #endif
1259 
1260 	unwind_init();
1261 }
1262 
1263 #ifdef CONFIG_X86_32
1264 
1265 static struct resource video_ram_resource = {
1266 	.name	= "Video RAM area",
1267 	.start	= 0xa0000,
1268 	.end	= 0xbffff,
1269 	.flags	= IORESOURCE_BUSY | IORESOURCE_MEM
1270 };
1271 
1272 void __init i386_reserve_resources(void)
1273 {
1274 	request_resource(&iomem_resource, &video_ram_resource);
1275 	reserve_standard_io_resources();
1276 }
1277 
1278 #endif /* CONFIG_X86_32 */
1279 
1280 static struct notifier_block kernel_offset_notifier = {
1281 	.notifier_call = dump_kernel_offset
1282 };
1283 
1284 static int __init register_kernel_offset_dumper(void)
1285 {
1286 	atomic_notifier_chain_register(&panic_notifier_list,
1287 					&kernel_offset_notifier);
1288 	return 0;
1289 }
1290 __initcall(register_kernel_offset_dumper);
1291