xref: /openbmc/linux/arch/x86/kernel/setup.c (revision 7a010c3c)
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/mtrr.h>
44 #include <asm/realmode.h>
45 #include <asm/olpc_ofw.h>
46 #include <asm/pci-direct.h>
47 #include <asm/prom.h>
48 #include <asm/proto.h>
49 #include <asm/thermal.h>
50 #include <asm/unwind.h>
51 #include <asm/vsyscall.h>
52 #include <linux/vmalloc.h>
53 
54 /*
55  * max_low_pfn_mapped: highest directly mapped pfn < 4 GB
56  * max_pfn_mapped:     highest directly mapped pfn > 4 GB
57  *
58  * The direct mapping only covers E820_TYPE_RAM regions, so the ranges and gaps are
59  * represented by pfn_mapped[].
60  */
61 unsigned long max_low_pfn_mapped;
62 unsigned long max_pfn_mapped;
63 
64 #ifdef CONFIG_DMI
65 RESERVE_BRK(dmi_alloc, 65536);
66 #endif
67 
68 
69 /*
70  * Range of the BSS area. The size of the BSS area is determined
71  * at link time, with RESERVE_BRK() facility reserving additional
72  * chunks.
73  */
74 unsigned long _brk_start = (unsigned long)__brk_base;
75 unsigned long _brk_end   = (unsigned long)__brk_base;
76 
77 struct boot_params boot_params;
78 
79 /*
80  * These are the four main kernel memory regions, we put them into
81  * the resource tree so that kdump tools and other debugging tools
82  * recover it:
83  */
84 
85 static struct resource rodata_resource = {
86 	.name	= "Kernel rodata",
87 	.start	= 0,
88 	.end	= 0,
89 	.flags	= IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM
90 };
91 
92 static struct resource data_resource = {
93 	.name	= "Kernel data",
94 	.start	= 0,
95 	.end	= 0,
96 	.flags	= IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM
97 };
98 
99 static struct resource code_resource = {
100 	.name	= "Kernel code",
101 	.start	= 0,
102 	.end	= 0,
103 	.flags	= IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM
104 };
105 
106 static struct resource bss_resource = {
107 	.name	= "Kernel bss",
108 	.start	= 0,
109 	.end	= 0,
110 	.flags	= IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM
111 };
112 
113 
114 #ifdef CONFIG_X86_32
115 /* CPU data as detected by the assembly code in head_32.S */
116 struct cpuinfo_x86 new_cpu_data;
117 
118 /* Common CPU data for all CPUs */
119 struct cpuinfo_x86 boot_cpu_data __read_mostly;
120 EXPORT_SYMBOL(boot_cpu_data);
121 
122 unsigned int def_to_bigsmp;
123 
124 struct apm_info apm_info;
125 EXPORT_SYMBOL(apm_info);
126 
127 #if defined(CONFIG_X86_SPEEDSTEP_SMI) || \
128 	defined(CONFIG_X86_SPEEDSTEP_SMI_MODULE)
129 struct ist_info ist_info;
130 EXPORT_SYMBOL(ist_info);
131 #else
132 struct ist_info ist_info;
133 #endif
134 
135 #else
136 struct cpuinfo_x86 boot_cpu_data __read_mostly;
137 EXPORT_SYMBOL(boot_cpu_data);
138 #endif
139 
140 
141 #if !defined(CONFIG_X86_PAE) || defined(CONFIG_X86_64)
142 __visible unsigned long mmu_cr4_features __ro_after_init;
143 #else
144 __visible unsigned long mmu_cr4_features __ro_after_init = X86_CR4_PAE;
145 #endif
146 
147 /* Boot loader ID and version as integers, for the benefit of proc_dointvec */
148 int bootloader_type, bootloader_version;
149 
150 /*
151  * Setup options
152  */
153 struct screen_info screen_info;
154 EXPORT_SYMBOL(screen_info);
155 struct edid_info edid_info;
156 EXPORT_SYMBOL_GPL(edid_info);
157 
158 extern int root_mountflags;
159 
160 unsigned long saved_video_mode;
161 
162 #define RAMDISK_IMAGE_START_MASK	0x07FF
163 #define RAMDISK_PROMPT_FLAG		0x8000
164 #define RAMDISK_LOAD_FLAG		0x4000
165 
166 static char __initdata command_line[COMMAND_LINE_SIZE];
167 #ifdef CONFIG_CMDLINE_BOOL
168 static char __initdata builtin_cmdline[COMMAND_LINE_SIZE] = CONFIG_CMDLINE;
169 #endif
170 
171 #if defined(CONFIG_EDD) || defined(CONFIG_EDD_MODULE)
172 struct edd edd;
173 #ifdef CONFIG_EDD_MODULE
174 EXPORT_SYMBOL(edd);
175 #endif
176 /**
177  * copy_edd() - Copy the BIOS EDD information
178  *              from boot_params into a safe place.
179  *
180  */
181 static inline void __init copy_edd(void)
182 {
183      memcpy(edd.mbr_signature, boot_params.edd_mbr_sig_buffer,
184 	    sizeof(edd.mbr_signature));
185      memcpy(edd.edd_info, boot_params.eddbuf, sizeof(edd.edd_info));
186      edd.mbr_signature_nr = boot_params.edd_mbr_sig_buf_entries;
187      edd.edd_info_nr = boot_params.eddbuf_entries;
188 }
189 #else
190 static inline void __init copy_edd(void)
191 {
192 }
193 #endif
194 
195 void * __init extend_brk(size_t size, size_t align)
196 {
197 	size_t mask = align - 1;
198 	void *ret;
199 
200 	BUG_ON(_brk_start == 0);
201 	BUG_ON(align & mask);
202 
203 	_brk_end = (_brk_end + mask) & ~mask;
204 	BUG_ON((char *)(_brk_end + size) > __brk_limit);
205 
206 	ret = (void *)_brk_end;
207 	_brk_end += size;
208 
209 	memset(ret, 0, size);
210 
211 	return ret;
212 }
213 
214 #ifdef CONFIG_X86_32
215 static void __init cleanup_highmap(void)
216 {
217 }
218 #endif
219 
220 static void __init reserve_brk(void)
221 {
222 	if (_brk_end > _brk_start)
223 		memblock_reserve(__pa_symbol(_brk_start),
224 				 _brk_end - _brk_start);
225 
226 	/* Mark brk area as locked down and no longer taking any
227 	   new allocations */
228 	_brk_start = 0;
229 }
230 
231 u64 relocated_ramdisk;
232 
233 #ifdef CONFIG_BLK_DEV_INITRD
234 
235 static u64 __init get_ramdisk_image(void)
236 {
237 	u64 ramdisk_image = boot_params.hdr.ramdisk_image;
238 
239 	ramdisk_image |= (u64)boot_params.ext_ramdisk_image << 32;
240 
241 	if (ramdisk_image == 0)
242 		ramdisk_image = phys_initrd_start;
243 
244 	return ramdisk_image;
245 }
246 static u64 __init get_ramdisk_size(void)
247 {
248 	u64 ramdisk_size = boot_params.hdr.ramdisk_size;
249 
250 	ramdisk_size |= (u64)boot_params.ext_ramdisk_size << 32;
251 
252 	if (ramdisk_size == 0)
253 		ramdisk_size = phys_initrd_size;
254 
255 	return ramdisk_size;
256 }
257 
258 static void __init relocate_initrd(void)
259 {
260 	/* Assume only end is not page aligned */
261 	u64 ramdisk_image = get_ramdisk_image();
262 	u64 ramdisk_size  = get_ramdisk_size();
263 	u64 area_size     = PAGE_ALIGN(ramdisk_size);
264 
265 	/* We need to move the initrd down into directly mapped mem */
266 	relocated_ramdisk = memblock_phys_alloc_range(area_size, PAGE_SIZE, 0,
267 						      PFN_PHYS(max_pfn_mapped));
268 	if (!relocated_ramdisk)
269 		panic("Cannot find place for new RAMDISK of size %lld\n",
270 		      ramdisk_size);
271 
272 	initrd_start = relocated_ramdisk + PAGE_OFFSET;
273 	initrd_end   = initrd_start + ramdisk_size;
274 	printk(KERN_INFO "Allocated new RAMDISK: [mem %#010llx-%#010llx]\n",
275 	       relocated_ramdisk, relocated_ramdisk + ramdisk_size - 1);
276 
277 	copy_from_early_mem((void *)initrd_start, ramdisk_image, ramdisk_size);
278 
279 	printk(KERN_INFO "Move RAMDISK from [mem %#010llx-%#010llx] to"
280 		" [mem %#010llx-%#010llx]\n",
281 		ramdisk_image, ramdisk_image + ramdisk_size - 1,
282 		relocated_ramdisk, relocated_ramdisk + ramdisk_size - 1);
283 }
284 
285 static void __init early_reserve_initrd(void)
286 {
287 	/* Assume only end is not page aligned */
288 	u64 ramdisk_image = get_ramdisk_image();
289 	u64 ramdisk_size  = get_ramdisk_size();
290 	u64 ramdisk_end   = PAGE_ALIGN(ramdisk_image + ramdisk_size);
291 
292 	if (!boot_params.hdr.type_of_loader ||
293 	    !ramdisk_image || !ramdisk_size)
294 		return;		/* No initrd provided by bootloader */
295 
296 	memblock_reserve(ramdisk_image, ramdisk_end - ramdisk_image);
297 }
298 
299 static void __init reserve_initrd(void)
300 {
301 	/* Assume only end is not page aligned */
302 	u64 ramdisk_image = get_ramdisk_image();
303 	u64 ramdisk_size  = get_ramdisk_size();
304 	u64 ramdisk_end   = PAGE_ALIGN(ramdisk_image + ramdisk_size);
305 
306 	if (!boot_params.hdr.type_of_loader ||
307 	    !ramdisk_image || !ramdisk_size)
308 		return;		/* No initrd provided by bootloader */
309 
310 	initrd_start = 0;
311 
312 	printk(KERN_INFO "RAMDISK: [mem %#010llx-%#010llx]\n", ramdisk_image,
313 			ramdisk_end - 1);
314 
315 	if (pfn_range_is_mapped(PFN_DOWN(ramdisk_image),
316 				PFN_DOWN(ramdisk_end))) {
317 		/* All are mapped, easy case */
318 		initrd_start = ramdisk_image + PAGE_OFFSET;
319 		initrd_end = initrd_start + ramdisk_size;
320 		return;
321 	}
322 
323 	relocate_initrd();
324 
325 	memblock_free(ramdisk_image, ramdisk_end - ramdisk_image);
326 }
327 
328 #else
329 static void __init early_reserve_initrd(void)
330 {
331 }
332 static void __init reserve_initrd(void)
333 {
334 }
335 #endif /* CONFIG_BLK_DEV_INITRD */
336 
337 static void __init parse_setup_data(void)
338 {
339 	struct setup_data *data;
340 	u64 pa_data, pa_next;
341 
342 	pa_data = boot_params.hdr.setup_data;
343 	while (pa_data) {
344 		u32 data_len, data_type;
345 
346 		data = early_memremap(pa_data, sizeof(*data));
347 		data_len = data->len + sizeof(struct setup_data);
348 		data_type = data->type;
349 		pa_next = data->next;
350 		early_memunmap(data, sizeof(*data));
351 
352 		switch (data_type) {
353 		case SETUP_E820_EXT:
354 			e820__memory_setup_extended(pa_data, data_len);
355 			break;
356 		case SETUP_DTB:
357 			add_dtb(pa_data);
358 			break;
359 		case SETUP_EFI:
360 			parse_efi_setup(pa_data, data_len);
361 			break;
362 		default:
363 			break;
364 		}
365 		pa_data = pa_next;
366 	}
367 }
368 
369 static void __init memblock_x86_reserve_range_setup_data(void)
370 {
371 	struct setup_data *data;
372 	u64 pa_data;
373 
374 	pa_data = boot_params.hdr.setup_data;
375 	while (pa_data) {
376 		data = early_memremap(pa_data, sizeof(*data));
377 		memblock_reserve(pa_data, sizeof(*data) + data->len);
378 
379 		if (data->type == SETUP_INDIRECT &&
380 		    ((struct setup_indirect *)data->data)->type != SETUP_INDIRECT)
381 			memblock_reserve(((struct setup_indirect *)data->data)->addr,
382 					 ((struct setup_indirect *)data->data)->len);
383 
384 		pa_data = data->next;
385 		early_memunmap(data, sizeof(*data));
386 	}
387 }
388 
389 /*
390  * --------- Crashkernel reservation ------------------------------
391  */
392 
393 #ifdef CONFIG_KEXEC_CORE
394 
395 /* 16M alignment for crash kernel regions */
396 #define CRASH_ALIGN		SZ_16M
397 
398 /*
399  * Keep the crash kernel below this limit.
400  *
401  * Earlier 32-bits kernels would limit the kernel to the low 512 MB range
402  * due to mapping restrictions.
403  *
404  * 64-bit kdump kernels need to be restricted to be under 64 TB, which is
405  * the upper limit of system RAM in 4-level paging mode. Since the kdump
406  * jump could be from 5-level paging to 4-level paging, the jump will fail if
407  * the kernel is put above 64 TB, and during the 1st kernel bootup there's
408  * no good way to detect the paging mode of the target kernel which will be
409  * loaded for dumping.
410  */
411 #ifdef CONFIG_X86_32
412 # define CRASH_ADDR_LOW_MAX	SZ_512M
413 # define CRASH_ADDR_HIGH_MAX	SZ_512M
414 #else
415 # define CRASH_ADDR_LOW_MAX	SZ_4G
416 # define CRASH_ADDR_HIGH_MAX	SZ_64T
417 #endif
418 
419 static int __init reserve_crashkernel_low(void)
420 {
421 #ifdef CONFIG_X86_64
422 	unsigned long long base, low_base = 0, low_size = 0;
423 	unsigned long low_mem_limit;
424 	int ret;
425 
426 	low_mem_limit = min(memblock_phys_mem_size(), CRASH_ADDR_LOW_MAX);
427 
428 	/* crashkernel=Y,low */
429 	ret = parse_crashkernel_low(boot_command_line, low_mem_limit, &low_size, &base);
430 	if (ret) {
431 		/*
432 		 * two parts from kernel/dma/swiotlb.c:
433 		 * -swiotlb size: user-specified with swiotlb= or default.
434 		 *
435 		 * -swiotlb overflow buffer: now hardcoded to 32k. We round it
436 		 * to 8M for other buffers that may need to stay low too. Also
437 		 * make sure we allocate enough extra low memory so that we
438 		 * don't run out of DMA buffers for 32-bit devices.
439 		 */
440 		low_size = max(swiotlb_size_or_default() + (8UL << 20), 256UL << 20);
441 	} else {
442 		/* passed with crashkernel=0,low ? */
443 		if (!low_size)
444 			return 0;
445 	}
446 
447 	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, 0, CRASH_ADDR_LOW_MAX);
448 	if (!low_base) {
449 		pr_err("Cannot reserve %ldMB crashkernel low memory, please try smaller size.\n",
450 		       (unsigned long)(low_size >> 20));
451 		return -ENOMEM;
452 	}
453 
454 	pr_info("Reserving %ldMB of low memory at %ldMB for crashkernel (low RAM limit: %ldMB)\n",
455 		(unsigned long)(low_size >> 20),
456 		(unsigned long)(low_base >> 20),
457 		(unsigned long)(low_mem_limit >> 20));
458 
459 	crashk_low_res.start = low_base;
460 	crashk_low_res.end   = low_base + low_size - 1;
461 	insert_resource(&iomem_resource, &crashk_low_res);
462 #endif
463 	return 0;
464 }
465 
466 static void __init reserve_crashkernel(void)
467 {
468 	unsigned long long crash_size, crash_base, total_mem;
469 	bool high = false;
470 	int ret;
471 
472 	total_mem = memblock_phys_mem_size();
473 
474 	/* crashkernel=XM */
475 	ret = parse_crashkernel(boot_command_line, total_mem, &crash_size, &crash_base);
476 	if (ret != 0 || crash_size <= 0) {
477 		/* crashkernel=X,high */
478 		ret = parse_crashkernel_high(boot_command_line, total_mem,
479 					     &crash_size, &crash_base);
480 		if (ret != 0 || crash_size <= 0)
481 			return;
482 		high = true;
483 	}
484 
485 	if (xen_pv_domain()) {
486 		pr_info("Ignoring crashkernel for a Xen PV domain\n");
487 		return;
488 	}
489 
490 	/* 0 means: find the address automatically */
491 	if (!crash_base) {
492 		/*
493 		 * Set CRASH_ADDR_LOW_MAX upper bound for crash memory,
494 		 * crashkernel=x,high reserves memory over 4G, also allocates
495 		 * 256M extra low memory for DMA buffers and swiotlb.
496 		 * But the extra memory is not required for all machines.
497 		 * So try low memory first and fall back to high memory
498 		 * unless "crashkernel=size[KMG],high" is specified.
499 		 */
500 		if (!high)
501 			crash_base = memblock_phys_alloc_range(crash_size,
502 						CRASH_ALIGN, CRASH_ALIGN,
503 						CRASH_ADDR_LOW_MAX);
504 		if (!crash_base)
505 			crash_base = memblock_phys_alloc_range(crash_size,
506 						CRASH_ALIGN, CRASH_ALIGN,
507 						CRASH_ADDR_HIGH_MAX);
508 		if (!crash_base) {
509 			pr_info("crashkernel reservation failed - No suitable area found.\n");
510 			return;
511 		}
512 	} else {
513 		unsigned long long start;
514 
515 		start = memblock_phys_alloc_range(crash_size, SZ_1M, crash_base,
516 						  crash_base + crash_size);
517 		if (start != crash_base) {
518 			pr_info("crashkernel reservation failed - memory is in use.\n");
519 			return;
520 		}
521 	}
522 
523 	if (crash_base >= (1ULL << 32) && reserve_crashkernel_low()) {
524 		memblock_free(crash_base, crash_size);
525 		return;
526 	}
527 
528 	pr_info("Reserving %ldMB of memory at %ldMB for crashkernel (System RAM: %ldMB)\n",
529 		(unsigned long)(crash_size >> 20),
530 		(unsigned long)(crash_base >> 20),
531 		(unsigned long)(total_mem >> 20));
532 
533 	crashk_res.start = crash_base;
534 	crashk_res.end   = crash_base + crash_size - 1;
535 	insert_resource(&iomem_resource, &crashk_res);
536 }
537 #else
538 static void __init reserve_crashkernel(void)
539 {
540 }
541 #endif
542 
543 static struct resource standard_io_resources[] = {
544 	{ .name = "dma1", .start = 0x00, .end = 0x1f,
545 		.flags = IORESOURCE_BUSY | IORESOURCE_IO },
546 	{ .name = "pic1", .start = 0x20, .end = 0x21,
547 		.flags = IORESOURCE_BUSY | IORESOURCE_IO },
548 	{ .name = "timer0", .start = 0x40, .end = 0x43,
549 		.flags = IORESOURCE_BUSY | IORESOURCE_IO },
550 	{ .name = "timer1", .start = 0x50, .end = 0x53,
551 		.flags = IORESOURCE_BUSY | IORESOURCE_IO },
552 	{ .name = "keyboard", .start = 0x60, .end = 0x60,
553 		.flags = IORESOURCE_BUSY | IORESOURCE_IO },
554 	{ .name = "keyboard", .start = 0x64, .end = 0x64,
555 		.flags = IORESOURCE_BUSY | IORESOURCE_IO },
556 	{ .name = "dma page reg", .start = 0x80, .end = 0x8f,
557 		.flags = IORESOURCE_BUSY | IORESOURCE_IO },
558 	{ .name = "pic2", .start = 0xa0, .end = 0xa1,
559 		.flags = IORESOURCE_BUSY | IORESOURCE_IO },
560 	{ .name = "dma2", .start = 0xc0, .end = 0xdf,
561 		.flags = IORESOURCE_BUSY | IORESOURCE_IO },
562 	{ .name = "fpu", .start = 0xf0, .end = 0xff,
563 		.flags = IORESOURCE_BUSY | IORESOURCE_IO }
564 };
565 
566 void __init reserve_standard_io_resources(void)
567 {
568 	int i;
569 
570 	/* request I/O space for devices used on all i[345]86 PCs */
571 	for (i = 0; i < ARRAY_SIZE(standard_io_resources); i++)
572 		request_resource(&ioport_resource, &standard_io_resources[i]);
573 
574 }
575 
576 static bool __init snb_gfx_workaround_needed(void)
577 {
578 #ifdef CONFIG_PCI
579 	int i;
580 	u16 vendor, devid;
581 	static const __initconst u16 snb_ids[] = {
582 		0x0102,
583 		0x0112,
584 		0x0122,
585 		0x0106,
586 		0x0116,
587 		0x0126,
588 		0x010a,
589 	};
590 
591 	/* Assume no if something weird is going on with PCI */
592 	if (!early_pci_allowed())
593 		return false;
594 
595 	vendor = read_pci_config_16(0, 2, 0, PCI_VENDOR_ID);
596 	if (vendor != 0x8086)
597 		return false;
598 
599 	devid = read_pci_config_16(0, 2, 0, PCI_DEVICE_ID);
600 	for (i = 0; i < ARRAY_SIZE(snb_ids); i++)
601 		if (devid == snb_ids[i])
602 			return true;
603 #endif
604 
605 	return false;
606 }
607 
608 /*
609  * Sandy Bridge graphics has trouble with certain ranges, exclude
610  * them from allocation.
611  */
612 static void __init trim_snb_memory(void)
613 {
614 	static const __initconst unsigned long bad_pages[] = {
615 		0x20050000,
616 		0x20110000,
617 		0x20130000,
618 		0x20138000,
619 		0x40004000,
620 	};
621 	int i;
622 
623 	if (!snb_gfx_workaround_needed())
624 		return;
625 
626 	printk(KERN_DEBUG "reserving inaccessible SNB gfx pages\n");
627 
628 	/*
629 	 * SandyBridge integrated graphics devices have a bug that prevents
630 	 * them from accessing certain memory ranges, namely anything below
631 	 * 1M and in the pages listed in bad_pages[] above.
632 	 *
633 	 * To avoid these pages being ever accessed by SNB gfx devices reserve
634 	 * bad_pages that have not already been reserved at boot time.
635 	 * All memory below the 1 MB mark is anyway reserved later during
636 	 * setup_arch(), so there is no need to reserve it here.
637 	 */
638 
639 	for (i = 0; i < ARRAY_SIZE(bad_pages); i++) {
640 		if (memblock_reserve(bad_pages[i], PAGE_SIZE))
641 			printk(KERN_WARNING "failed to reserve 0x%08lx\n",
642 			       bad_pages[i]);
643 	}
644 }
645 
646 static void __init trim_bios_range(void)
647 {
648 	/*
649 	 * A special case is the first 4Kb of memory;
650 	 * This is a BIOS owned area, not kernel ram, but generally
651 	 * not listed as such in the E820 table.
652 	 *
653 	 * This typically reserves additional memory (64KiB by default)
654 	 * since some BIOSes are known to corrupt low memory.  See the
655 	 * Kconfig help text for X86_RESERVE_LOW.
656 	 */
657 	e820__range_update(0, PAGE_SIZE, E820_TYPE_RAM, E820_TYPE_RESERVED);
658 
659 	/*
660 	 * special case: Some BIOSes report the PC BIOS
661 	 * area (640Kb -> 1Mb) as RAM even though it is not.
662 	 * take them out.
663 	 */
664 	e820__range_remove(BIOS_BEGIN, BIOS_END - BIOS_BEGIN, E820_TYPE_RAM, 1);
665 
666 	e820__update_table(e820_table);
667 }
668 
669 /* called before trim_bios_range() to spare extra sanitize */
670 static void __init e820_add_kernel_range(void)
671 {
672 	u64 start = __pa_symbol(_text);
673 	u64 size = __pa_symbol(_end) - start;
674 
675 	/*
676 	 * Complain if .text .data and .bss are not marked as E820_TYPE_RAM and
677 	 * attempt to fix it by adding the range. We may have a confused BIOS,
678 	 * or the user may have used memmap=exactmap or memmap=xxM$yyM to
679 	 * exclude kernel range. If we really are running on top non-RAM,
680 	 * we will crash later anyways.
681 	 */
682 	if (e820__mapped_all(start, start + size, E820_TYPE_RAM))
683 		return;
684 
685 	pr_warn(".text .data .bss are not marked as E820_TYPE_RAM!\n");
686 	e820__range_remove(start, size, E820_TYPE_RAM, 0);
687 	e820__range_add(start, size, E820_TYPE_RAM);
688 }
689 
690 static void __init early_reserve_memory(void)
691 {
692 	/*
693 	 * Reserve the memory occupied by the kernel between _text and
694 	 * __end_of_kernel_reserve symbols. Any kernel sections after the
695 	 * __end_of_kernel_reserve symbol must be explicitly reserved with a
696 	 * separate memblock_reserve() or they will be discarded.
697 	 */
698 	memblock_reserve(__pa_symbol(_text),
699 			 (unsigned long)__end_of_kernel_reserve - (unsigned long)_text);
700 
701 	/*
702 	 * The first 4Kb of memory is a BIOS owned area, but generally it is
703 	 * not listed as such in the E820 table.
704 	 *
705 	 * Reserve the first 64K of memory since some BIOSes are known to
706 	 * corrupt low memory. After the real mode trampoline is allocated the
707 	 * rest of the memory below 640k is reserved.
708 	 *
709 	 * In addition, make sure page 0 is always reserved because on
710 	 * systems with L1TF its contents can be leaked to user processes.
711 	 */
712 	memblock_reserve(0, SZ_64K);
713 
714 	early_reserve_initrd();
715 
716 	if (efi_enabled(EFI_BOOT))
717 		efi_memblock_x86_reserve_range();
718 
719 	memblock_x86_reserve_range_setup_data();
720 
721 	reserve_ibft_region();
722 	reserve_bios_regions();
723 	trim_snb_memory();
724 }
725 
726 /*
727  * Dump out kernel offset information on panic.
728  */
729 static int
730 dump_kernel_offset(struct notifier_block *self, unsigned long v, void *p)
731 {
732 	if (kaslr_enabled()) {
733 		pr_emerg("Kernel Offset: 0x%lx from 0x%lx (relocation range: 0x%lx-0x%lx)\n",
734 			 kaslr_offset(),
735 			 __START_KERNEL,
736 			 __START_KERNEL_map,
737 			 MODULES_VADDR-1);
738 	} else {
739 		pr_emerg("Kernel Offset: disabled\n");
740 	}
741 
742 	return 0;
743 }
744 
745 /*
746  * Determine if we were loaded by an EFI loader.  If so, then we have also been
747  * passed the efi memmap, systab, etc., so we should use these data structures
748  * for initialization.  Note, the efi init code path is determined by the
749  * global efi_enabled. This allows the same kernel image to be used on existing
750  * systems (with a traditional BIOS) as well as on EFI systems.
751  */
752 /*
753  * setup_arch - architecture-specific boot-time initializations
754  *
755  * Note: On x86_64, fixmaps are ready for use even before this is called.
756  */
757 
758 void __init setup_arch(char **cmdline_p)
759 {
760 #ifdef CONFIG_X86_32
761 	memcpy(&boot_cpu_data, &new_cpu_data, sizeof(new_cpu_data));
762 
763 	/*
764 	 * copy kernel address range established so far and switch
765 	 * to the proper swapper page table
766 	 */
767 	clone_pgd_range(swapper_pg_dir     + KERNEL_PGD_BOUNDARY,
768 			initial_page_table + KERNEL_PGD_BOUNDARY,
769 			KERNEL_PGD_PTRS);
770 
771 	load_cr3(swapper_pg_dir);
772 	/*
773 	 * Note: Quark X1000 CPUs advertise PGE incorrectly and require
774 	 * a cr3 based tlb flush, so the following __flush_tlb_all()
775 	 * will not flush anything because the CPU quirk which clears
776 	 * X86_FEATURE_PGE has not been invoked yet. Though due to the
777 	 * load_cr3() above the TLB has been flushed already. The
778 	 * quirk is invoked before subsequent calls to __flush_tlb_all()
779 	 * so proper operation is guaranteed.
780 	 */
781 	__flush_tlb_all();
782 #else
783 	printk(KERN_INFO "Command line: %s\n", boot_command_line);
784 	boot_cpu_data.x86_phys_bits = MAX_PHYSMEM_BITS;
785 #endif
786 
787 	/*
788 	 * If we have OLPC OFW, we might end up relocating the fixmap due to
789 	 * reserve_top(), so do this before touching the ioremap area.
790 	 */
791 	olpc_ofw_detect();
792 
793 	idt_setup_early_traps();
794 	early_cpu_init();
795 	jump_label_init();
796 	static_call_init();
797 	early_ioremap_init();
798 
799 	setup_olpc_ofw_pgd();
800 
801 	ROOT_DEV = old_decode_dev(boot_params.hdr.root_dev);
802 	screen_info = boot_params.screen_info;
803 	edid_info = boot_params.edid_info;
804 #ifdef CONFIG_X86_32
805 	apm_info.bios = boot_params.apm_bios_info;
806 	ist_info = boot_params.ist_info;
807 #endif
808 	saved_video_mode = boot_params.hdr.vid_mode;
809 	bootloader_type = boot_params.hdr.type_of_loader;
810 	if ((bootloader_type >> 4) == 0xe) {
811 		bootloader_type &= 0xf;
812 		bootloader_type |= (boot_params.hdr.ext_loader_type+0x10) << 4;
813 	}
814 	bootloader_version  = bootloader_type & 0xf;
815 	bootloader_version |= boot_params.hdr.ext_loader_ver << 4;
816 
817 #ifdef CONFIG_BLK_DEV_RAM
818 	rd_image_start = boot_params.hdr.ram_size & RAMDISK_IMAGE_START_MASK;
819 #endif
820 #ifdef CONFIG_EFI
821 	if (!strncmp((char *)&boot_params.efi_info.efi_loader_signature,
822 		     EFI32_LOADER_SIGNATURE, 4)) {
823 		set_bit(EFI_BOOT, &efi.flags);
824 	} else if (!strncmp((char *)&boot_params.efi_info.efi_loader_signature,
825 		     EFI64_LOADER_SIGNATURE, 4)) {
826 		set_bit(EFI_BOOT, &efi.flags);
827 		set_bit(EFI_64BIT, &efi.flags);
828 	}
829 #endif
830 
831 	x86_init.oem.arch_setup();
832 
833 	iomem_resource.end = (1ULL << boot_cpu_data.x86_phys_bits) - 1;
834 	e820__memory_setup();
835 	parse_setup_data();
836 
837 	copy_edd();
838 
839 	if (!boot_params.hdr.root_flags)
840 		root_mountflags &= ~MS_RDONLY;
841 	setup_initial_init_mm(_text, _etext, _edata, (void *)_brk_end);
842 
843 	code_resource.start = __pa_symbol(_text);
844 	code_resource.end = __pa_symbol(_etext)-1;
845 	rodata_resource.start = __pa_symbol(__start_rodata);
846 	rodata_resource.end = __pa_symbol(__end_rodata)-1;
847 	data_resource.start = __pa_symbol(_sdata);
848 	data_resource.end = __pa_symbol(_edata)-1;
849 	bss_resource.start = __pa_symbol(__bss_start);
850 	bss_resource.end = __pa_symbol(__bss_stop)-1;
851 
852 #ifdef CONFIG_CMDLINE_BOOL
853 #ifdef CONFIG_CMDLINE_OVERRIDE
854 	strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);
855 #else
856 	if (builtin_cmdline[0]) {
857 		/* append boot loader cmdline to builtin */
858 		strlcat(builtin_cmdline, " ", COMMAND_LINE_SIZE);
859 		strlcat(builtin_cmdline, boot_command_line, COMMAND_LINE_SIZE);
860 		strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);
861 	}
862 #endif
863 #endif
864 
865 	strlcpy(command_line, boot_command_line, COMMAND_LINE_SIZE);
866 	*cmdline_p = command_line;
867 
868 	/*
869 	 * x86_configure_nx() is called before parse_early_param() to detect
870 	 * whether hardware doesn't support NX (so that the early EHCI debug
871 	 * console setup can safely call set_fixmap()). It may then be called
872 	 * again from within noexec_setup() during parsing early parameters
873 	 * to honor the respective command line option.
874 	 */
875 	x86_configure_nx();
876 
877 	parse_early_param();
878 
879 	/*
880 	 * Do some memory reservations *before* memory is added to
881 	 * memblock, so memblock allocations won't overwrite it.
882 	 * Do it after early param, so we could get (unlikely) panic from
883 	 * serial.
884 	 *
885 	 * After this point everything still needed from the boot loader or
886 	 * firmware or kernel text should be early reserved or marked not
887 	 * RAM in e820. All other memory is free game.
888 	 */
889 	early_reserve_memory();
890 
891 #ifdef CONFIG_MEMORY_HOTPLUG
892 	/*
893 	 * Memory used by the kernel cannot be hot-removed because Linux
894 	 * cannot migrate the kernel pages. When memory hotplug is
895 	 * enabled, we should prevent memblock from allocating memory
896 	 * for the kernel.
897 	 *
898 	 * ACPI SRAT records all hotpluggable memory ranges. But before
899 	 * SRAT is parsed, we don't know about it.
900 	 *
901 	 * The kernel image is loaded into memory at very early time. We
902 	 * cannot prevent this anyway. So on NUMA system, we set any
903 	 * node the kernel resides in as un-hotpluggable.
904 	 *
905 	 * Since on modern servers, one node could have double-digit
906 	 * gigabytes memory, we can assume the memory around the kernel
907 	 * image is also un-hotpluggable. So before SRAT is parsed, just
908 	 * allocate memory near the kernel image to try the best to keep
909 	 * the kernel away from hotpluggable memory.
910 	 */
911 	if (movable_node_is_enabled())
912 		memblock_set_bottom_up(true);
913 #endif
914 
915 	x86_report_nx();
916 
917 	if (acpi_mps_check()) {
918 #ifdef CONFIG_X86_LOCAL_APIC
919 		disable_apic = 1;
920 #endif
921 		setup_clear_cpu_cap(X86_FEATURE_APIC);
922 	}
923 
924 	e820__reserve_setup_data();
925 	e820__finish_early_params();
926 
927 	if (efi_enabled(EFI_BOOT))
928 		efi_init();
929 
930 	dmi_setup();
931 
932 	/*
933 	 * VMware detection requires dmi to be available, so this
934 	 * needs to be done after dmi_setup(), for the boot CPU.
935 	 */
936 	init_hypervisor_platform();
937 
938 	tsc_early_init();
939 	x86_init.resources.probe_roms();
940 
941 	/* after parse_early_param, so could debug it */
942 	insert_resource(&iomem_resource, &code_resource);
943 	insert_resource(&iomem_resource, &rodata_resource);
944 	insert_resource(&iomem_resource, &data_resource);
945 	insert_resource(&iomem_resource, &bss_resource);
946 
947 	e820_add_kernel_range();
948 	trim_bios_range();
949 #ifdef CONFIG_X86_32
950 	if (ppro_with_ram_bug()) {
951 		e820__range_update(0x70000000ULL, 0x40000ULL, E820_TYPE_RAM,
952 				  E820_TYPE_RESERVED);
953 		e820__update_table(e820_table);
954 		printk(KERN_INFO "fixed physical RAM map:\n");
955 		e820__print_table("bad_ppro");
956 	}
957 #else
958 	early_gart_iommu_check();
959 #endif
960 
961 	/*
962 	 * partially used pages are not usable - thus
963 	 * we are rounding upwards:
964 	 */
965 	max_pfn = e820__end_of_ram_pfn();
966 
967 	/* update e820 for memory not covered by WB MTRRs */
968 	mtrr_bp_init();
969 	if (mtrr_trim_uncached_memory(max_pfn))
970 		max_pfn = e820__end_of_ram_pfn();
971 
972 	max_possible_pfn = max_pfn;
973 
974 	/*
975 	 * This call is required when the CPU does not support PAT. If
976 	 * mtrr_bp_init() invoked it already via pat_init() the call has no
977 	 * effect.
978 	 */
979 	init_cache_modes();
980 
981 	/*
982 	 * Define random base addresses for memory sections after max_pfn is
983 	 * defined and before each memory section base is used.
984 	 */
985 	kernel_randomize_memory();
986 
987 #ifdef CONFIG_X86_32
988 	/* max_low_pfn get updated here */
989 	find_low_pfn_range();
990 #else
991 	check_x2apic();
992 
993 	/* How many end-of-memory variables you have, grandma! */
994 	/* need this before calling reserve_initrd */
995 	if (max_pfn > (1UL<<(32 - PAGE_SHIFT)))
996 		max_low_pfn = e820__end_of_low_ram_pfn();
997 	else
998 		max_low_pfn = max_pfn;
999 
1000 	high_memory = (void *)__va(max_pfn * PAGE_SIZE - 1) + 1;
1001 #endif
1002 
1003 	/*
1004 	 * Find and reserve possible boot-time SMP configuration:
1005 	 */
1006 	find_smp_config();
1007 
1008 	early_alloc_pgt_buf();
1009 
1010 	/*
1011 	 * Need to conclude brk, before e820__memblock_setup()
1012 	 * it could use memblock_find_in_range, could overlap with
1013 	 * brk area.
1014 	 */
1015 	reserve_brk();
1016 
1017 	cleanup_highmap();
1018 
1019 	memblock_set_current_limit(ISA_END_ADDRESS);
1020 	e820__memblock_setup();
1021 
1022 	/*
1023 	 * Needs to run after memblock setup because it needs the physical
1024 	 * memory size.
1025 	 */
1026 	sev_setup_arch();
1027 
1028 	efi_fake_memmap();
1029 	efi_find_mirror();
1030 	efi_esrt_init();
1031 	efi_mokvar_table_init();
1032 
1033 	/*
1034 	 * The EFI specification says that boot service code won't be
1035 	 * called after ExitBootServices(). This is, in fact, a lie.
1036 	 */
1037 	efi_reserve_boot_services();
1038 
1039 	/* preallocate 4k for mptable mpc */
1040 	e820__memblock_alloc_reserved_mpc_new();
1041 
1042 #ifdef CONFIG_X86_CHECK_BIOS_CORRUPTION
1043 	setup_bios_corruption_check();
1044 #endif
1045 
1046 #ifdef CONFIG_X86_32
1047 	printk(KERN_DEBUG "initial memory mapped: [mem 0x00000000-%#010lx]\n",
1048 			(max_pfn_mapped<<PAGE_SHIFT) - 1);
1049 #endif
1050 
1051 	/*
1052 	 * Find free memory for the real mode trampoline and place it there. If
1053 	 * there is not enough free memory under 1M, on EFI-enabled systems
1054 	 * there will be additional attempt to reclaim the memory for the real
1055 	 * mode trampoline at efi_free_boot_services().
1056 	 *
1057 	 * Unconditionally reserve the entire first 1M of RAM because BIOSes
1058 	 * are known to corrupt low memory and several hundred kilobytes are not
1059 	 * worth complex detection what memory gets clobbered. Windows does the
1060 	 * same thing for very similar reasons.
1061 	 *
1062 	 * Moreover, on machines with SandyBridge graphics or in setups that use
1063 	 * crashkernel the entire 1M is reserved anyway.
1064 	 */
1065 	reserve_real_mode();
1066 
1067 	init_mem_mapping();
1068 
1069 	idt_setup_early_pf();
1070 
1071 	/*
1072 	 * Update mmu_cr4_features (and, indirectly, trampoline_cr4_features)
1073 	 * with the current CR4 value.  This may not be necessary, but
1074 	 * auditing all the early-boot CR4 manipulation would be needed to
1075 	 * rule it out.
1076 	 *
1077 	 * Mask off features that don't work outside long mode (just
1078 	 * PCIDE for now).
1079 	 */
1080 	mmu_cr4_features = __read_cr4() & ~X86_CR4_PCIDE;
1081 
1082 	memblock_set_current_limit(get_max_mapped());
1083 
1084 	/*
1085 	 * NOTE: On x86-32, only from this point on, fixmaps are ready for use.
1086 	 */
1087 
1088 #ifdef CONFIG_PROVIDE_OHCI1394_DMA_INIT
1089 	if (init_ohci1394_dma_early)
1090 		init_ohci1394_dma_on_all_controllers();
1091 #endif
1092 	/* Allocate bigger log buffer */
1093 	setup_log_buf(1);
1094 
1095 	if (efi_enabled(EFI_BOOT)) {
1096 		switch (boot_params.secure_boot) {
1097 		case efi_secureboot_mode_disabled:
1098 			pr_info("Secure boot disabled\n");
1099 			break;
1100 		case efi_secureboot_mode_enabled:
1101 			pr_info("Secure boot enabled\n");
1102 			break;
1103 		default:
1104 			pr_info("Secure boot could not be determined\n");
1105 			break;
1106 		}
1107 	}
1108 
1109 	reserve_initrd();
1110 
1111 	acpi_table_upgrade();
1112 	/* Look for ACPI tables and reserve memory occupied by them. */
1113 	acpi_boot_table_init();
1114 
1115 	vsmp_init();
1116 
1117 	io_delay_init();
1118 
1119 	early_platform_quirks();
1120 
1121 	early_acpi_boot_init();
1122 
1123 	initmem_init();
1124 	dma_contiguous_reserve(max_pfn_mapped << PAGE_SHIFT);
1125 
1126 	if (boot_cpu_has(X86_FEATURE_GBPAGES))
1127 		hugetlb_cma_reserve(PUD_SHIFT - PAGE_SHIFT);
1128 
1129 	/*
1130 	 * Reserve memory for crash kernel after SRAT is parsed so that it
1131 	 * won't consume hotpluggable memory.
1132 	 */
1133 	reserve_crashkernel();
1134 
1135 	memblock_find_dma_reserve();
1136 
1137 	if (!early_xdbc_setup_hardware())
1138 		early_xdbc_register_console();
1139 
1140 	x86_init.paging.pagetable_init();
1141 
1142 	kasan_init();
1143 
1144 	/*
1145 	 * Sync back kernel address range.
1146 	 *
1147 	 * FIXME: Can the later sync in setup_cpu_entry_areas() replace
1148 	 * this call?
1149 	 */
1150 	sync_initial_page_table();
1151 
1152 	tboot_probe();
1153 
1154 	map_vsyscall();
1155 
1156 	generic_apic_probe();
1157 
1158 	early_quirks();
1159 
1160 	/*
1161 	 * Read APIC and some other early information from ACPI tables.
1162 	 */
1163 	acpi_boot_init();
1164 	x86_dtb_init();
1165 
1166 	/*
1167 	 * get boot-time SMP configuration:
1168 	 */
1169 	get_smp_config();
1170 
1171 	/*
1172 	 * Systems w/o ACPI and mptables might not have it mapped the local
1173 	 * APIC yet, but prefill_possible_map() might need to access it.
1174 	 */
1175 	init_apic_mappings();
1176 
1177 	prefill_possible_map();
1178 
1179 	init_cpu_to_node();
1180 	init_gi_nodes();
1181 
1182 	io_apic_init_mappings();
1183 
1184 	x86_init.hyper.guest_late_init();
1185 
1186 	e820__reserve_resources();
1187 	e820__register_nosave_regions(max_pfn);
1188 
1189 	x86_init.resources.reserve_resources();
1190 
1191 	e820__setup_pci_gap();
1192 
1193 #ifdef CONFIG_VT
1194 #if defined(CONFIG_VGA_CONSOLE)
1195 	if (!efi_enabled(EFI_BOOT) || (efi_mem_type(0xa0000) != EFI_CONVENTIONAL_MEMORY))
1196 		conswitchp = &vga_con;
1197 #endif
1198 #endif
1199 	x86_init.oem.banner();
1200 
1201 	x86_init.timers.wallclock_init();
1202 
1203 	/*
1204 	 * This needs to run before setup_local_APIC() which soft-disables the
1205 	 * local APIC temporarily and that masks the thermal LVT interrupt,
1206 	 * leading to softlockups on machines which have configured SMI
1207 	 * interrupt delivery.
1208 	 */
1209 	therm_lvt_init();
1210 
1211 	mcheck_init();
1212 
1213 	register_refined_jiffies(CLOCK_TICK_RATE);
1214 
1215 #ifdef CONFIG_EFI
1216 	if (efi_enabled(EFI_BOOT))
1217 		efi_apply_memmap_quirks();
1218 #endif
1219 
1220 	unwind_init();
1221 }
1222 
1223 #ifdef CONFIG_X86_32
1224 
1225 static struct resource video_ram_resource = {
1226 	.name	= "Video RAM area",
1227 	.start	= 0xa0000,
1228 	.end	= 0xbffff,
1229 	.flags	= IORESOURCE_BUSY | IORESOURCE_MEM
1230 };
1231 
1232 void __init i386_reserve_resources(void)
1233 {
1234 	request_resource(&iomem_resource, &video_ram_resource);
1235 	reserve_standard_io_resources();
1236 }
1237 
1238 #endif /* CONFIG_X86_32 */
1239 
1240 static struct notifier_block kernel_offset_notifier = {
1241 	.notifier_call = dump_kernel_offset
1242 };
1243 
1244 static int __init register_kernel_offset_dumper(void)
1245 {
1246 	atomic_notifier_chain_register(&panic_notifier_list,
1247 					&kernel_offset_notifier);
1248 	return 0;
1249 }
1250 __initcall(register_kernel_offset_dumper);
1251