xref: /openbmc/linux/arch/x86/kernel/e820.c (revision c43b984f)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Low level x86 E820 memory map handling functions.
4  *
5  * The firmware and bootloader passes us the "E820 table", which is the primary
6  * physical memory layout description available about x86 systems.
7  *
8  * The kernel takes the E820 memory layout and optionally modifies it with
9  * quirks and other tweaks, and feeds that into the generic Linux memory
10  * allocation code routines via a platform independent interface (memblock, etc.).
11  */
12 #include <linux/crash_dump.h>
13 #include <linux/memblock.h>
14 #include <linux/suspend.h>
15 #include <linux/acpi.h>
16 #include <linux/firmware-map.h>
17 #include <linux/sort.h>
18 #include <linux/memory_hotplug.h>
19 
20 #include <asm/e820/api.h>
21 #include <asm/setup.h>
22 
23 /*
24  * We organize the E820 table into three main data structures:
25  *
26  * - 'e820_table_firmware': the original firmware version passed to us by the
27  *   bootloader - not modified by the kernel. It is composed of two parts:
28  *   the first 128 E820 memory entries in boot_params.e820_table and the remaining
29  *   (if any) entries of the SETUP_E820_EXT nodes. We use this to:
30  *
31  *       - inform the user about the firmware's notion of memory layout
32  *         via /sys/firmware/memmap
33  *
34  *       - the hibernation code uses it to generate a kernel-independent CRC32
35  *         checksum of the physical memory layout of a system.
36  *
37  * - 'e820_table_kexec': a slightly modified (by the kernel) firmware version
38  *   passed to us by the bootloader - the major difference between
39  *   e820_table_firmware[] and this one is that, the latter marks the setup_data
40  *   list created by the EFI boot stub as reserved, so that kexec can reuse the
41  *   setup_data information in the second kernel. Besides, e820_table_kexec[]
42  *   might also be modified by the kexec itself to fake a mptable.
43  *   We use this to:
44  *
45  *       - kexec, which is a bootloader in disguise, uses the original E820
46  *         layout to pass to the kexec-ed kernel. This way the original kernel
47  *         can have a restricted E820 map while the kexec()-ed kexec-kernel
48  *         can have access to full memory - etc.
49  *
50  * - 'e820_table': this is the main E820 table that is massaged by the
51  *   low level x86 platform code, or modified by boot parameters, before
52  *   passed on to higher level MM layers.
53  *
54  * Once the E820 map has been converted to the standard Linux memory layout
55  * information its role stops - modifying it has no effect and does not get
56  * re-propagated. So its main role is a temporary bootstrap storage of firmware
57  * specific memory layout data during early bootup.
58  */
59 static struct e820_table e820_table_init		__initdata;
60 static struct e820_table e820_table_kexec_init		__initdata;
61 static struct e820_table e820_table_firmware_init	__initdata;
62 
63 struct e820_table *e820_table __refdata			= &e820_table_init;
64 struct e820_table *e820_table_kexec __refdata		= &e820_table_kexec_init;
65 struct e820_table *e820_table_firmware __refdata	= &e820_table_firmware_init;
66 
67 /* For PCI or other memory-mapped resources */
68 unsigned long pci_mem_start = 0xaeedbabe;
69 #ifdef CONFIG_PCI
70 EXPORT_SYMBOL(pci_mem_start);
71 #endif
72 
73 /*
74  * This function checks if any part of the range <start,end> is mapped
75  * with type.
76  */
_e820__mapped_any(struct e820_table * table,u64 start,u64 end,enum e820_type type)77 static bool _e820__mapped_any(struct e820_table *table,
78 			      u64 start, u64 end, enum e820_type type)
79 {
80 	int i;
81 
82 	for (i = 0; i < table->nr_entries; i++) {
83 		struct e820_entry *entry = &table->entries[i];
84 
85 		if (type && entry->type != type)
86 			continue;
87 		if (entry->addr >= end || entry->addr + entry->size <= start)
88 			continue;
89 		return true;
90 	}
91 	return false;
92 }
93 
e820__mapped_raw_any(u64 start,u64 end,enum e820_type type)94 bool e820__mapped_raw_any(u64 start, u64 end, enum e820_type type)
95 {
96 	return _e820__mapped_any(e820_table_firmware, start, end, type);
97 }
98 EXPORT_SYMBOL_GPL(e820__mapped_raw_any);
99 
e820__mapped_any(u64 start,u64 end,enum e820_type type)100 bool e820__mapped_any(u64 start, u64 end, enum e820_type type)
101 {
102 	return _e820__mapped_any(e820_table, start, end, type);
103 }
104 EXPORT_SYMBOL_GPL(e820__mapped_any);
105 
106 /*
107  * This function checks if the entire <start,end> range is mapped with 'type'.
108  *
109  * Note: this function only works correctly once the E820 table is sorted and
110  * not-overlapping (at least for the range specified), which is the case normally.
111  */
__e820__mapped_all(u64 start,u64 end,enum e820_type type)112 static struct e820_entry *__e820__mapped_all(u64 start, u64 end,
113 					     enum e820_type type)
114 {
115 	int i;
116 
117 	for (i = 0; i < e820_table->nr_entries; i++) {
118 		struct e820_entry *entry = &e820_table->entries[i];
119 
120 		if (type && entry->type != type)
121 			continue;
122 
123 		/* Is the region (part) in overlap with the current region? */
124 		if (entry->addr >= end || entry->addr + entry->size <= start)
125 			continue;
126 
127 		/*
128 		 * If the region is at the beginning of <start,end> we move
129 		 * 'start' to the end of the region since it's ok until there
130 		 */
131 		if (entry->addr <= start)
132 			start = entry->addr + entry->size;
133 
134 		/*
135 		 * If 'start' is now at or beyond 'end', we're done, full
136 		 * coverage of the desired range exists:
137 		 */
138 		if (start >= end)
139 			return entry;
140 	}
141 
142 	return NULL;
143 }
144 
145 /*
146  * This function checks if the entire range <start,end> is mapped with type.
147  */
e820__mapped_all(u64 start,u64 end,enum e820_type type)148 bool __init e820__mapped_all(u64 start, u64 end, enum e820_type type)
149 {
150 	return __e820__mapped_all(start, end, type);
151 }
152 
153 /*
154  * This function returns the type associated with the range <start,end>.
155  */
e820__get_entry_type(u64 start,u64 end)156 int e820__get_entry_type(u64 start, u64 end)
157 {
158 	struct e820_entry *entry = __e820__mapped_all(start, end, 0);
159 
160 	return entry ? entry->type : -EINVAL;
161 }
162 
163 /*
164  * Add a memory region to the kernel E820 map.
165  */
__e820__range_add(struct e820_table * table,u64 start,u64 size,enum e820_type type)166 static void __init __e820__range_add(struct e820_table *table, u64 start, u64 size, enum e820_type type)
167 {
168 	int x = table->nr_entries;
169 
170 	if (x >= ARRAY_SIZE(table->entries)) {
171 		pr_err("too many entries; ignoring [mem %#010llx-%#010llx]\n",
172 		       start, start + size - 1);
173 		return;
174 	}
175 
176 	table->entries[x].addr = start;
177 	table->entries[x].size = size;
178 	table->entries[x].type = type;
179 	table->nr_entries++;
180 }
181 
e820__range_add(u64 start,u64 size,enum e820_type type)182 void __init e820__range_add(u64 start, u64 size, enum e820_type type)
183 {
184 	__e820__range_add(e820_table, start, size, type);
185 }
186 
e820_print_type(enum e820_type type)187 static void __init e820_print_type(enum e820_type type)
188 {
189 	switch (type) {
190 	case E820_TYPE_RAM:		/* Fall through: */
191 	case E820_TYPE_RESERVED_KERN:	pr_cont("usable");			break;
192 	case E820_TYPE_RESERVED:	pr_cont("reserved");			break;
193 	case E820_TYPE_SOFT_RESERVED:	pr_cont("soft reserved");		break;
194 	case E820_TYPE_ACPI:		pr_cont("ACPI data");			break;
195 	case E820_TYPE_NVS:		pr_cont("ACPI NVS");			break;
196 	case E820_TYPE_UNUSABLE:	pr_cont("unusable");			break;
197 	case E820_TYPE_PMEM:		/* Fall through: */
198 	case E820_TYPE_PRAM:		pr_cont("persistent (type %u)", type);	break;
199 	default:			pr_cont("type %u", type);		break;
200 	}
201 }
202 
e820__print_table(char * who)203 void __init e820__print_table(char *who)
204 {
205 	int i;
206 
207 	for (i = 0; i < e820_table->nr_entries; i++) {
208 		pr_info("%s: [mem %#018Lx-%#018Lx] ",
209 			who,
210 			e820_table->entries[i].addr,
211 			e820_table->entries[i].addr + e820_table->entries[i].size - 1);
212 
213 		e820_print_type(e820_table->entries[i].type);
214 		pr_cont("\n");
215 	}
216 }
217 
218 /*
219  * Sanitize an E820 map.
220  *
221  * Some E820 layouts include overlapping entries. The following
222  * replaces the original E820 map with a new one, removing overlaps,
223  * and resolving conflicting memory types in favor of highest
224  * numbered type.
225  *
226  * The input parameter 'entries' points to an array of 'struct
227  * e820_entry' which on entry has elements in the range [0, *nr_entries)
228  * valid, and which has space for up to max_nr_entries entries.
229  * On return, the resulting sanitized E820 map entries will be in
230  * overwritten in the same location, starting at 'entries'.
231  *
232  * The integer pointed to by nr_entries must be valid on entry (the
233  * current number of valid entries located at 'entries'). If the
234  * sanitizing succeeds the *nr_entries will be updated with the new
235  * number of valid entries (something no more than max_nr_entries).
236  *
237  * The return value from e820__update_table() is zero if it
238  * successfully 'sanitized' the map entries passed in, and is -1
239  * if it did nothing, which can happen if either of (1) it was
240  * only passed one map entry, or (2) any of the input map entries
241  * were invalid (start + size < start, meaning that the size was
242  * so big the described memory range wrapped around through zero.)
243  *
244  *	Visually we're performing the following
245  *	(1,2,3,4 = memory types)...
246  *
247  *	Sample memory map (w/overlaps):
248  *	   ____22__________________
249  *	   ______________________4_
250  *	   ____1111________________
251  *	   _44_____________________
252  *	   11111111________________
253  *	   ____________________33__
254  *	   ___________44___________
255  *	   __________33333_________
256  *	   ______________22________
257  *	   ___________________2222_
258  *	   _________111111111______
259  *	   _____________________11_
260  *	   _________________4______
261  *
262  *	Sanitized equivalent (no overlap):
263  *	   1_______________________
264  *	   _44_____________________
265  *	   ___1____________________
266  *	   ____22__________________
267  *	   ______11________________
268  *	   _________1______________
269  *	   __________3_____________
270  *	   ___________44___________
271  *	   _____________33_________
272  *	   _______________2________
273  *	   ________________1_______
274  *	   _________________4______
275  *	   ___________________2____
276  *	   ____________________33__
277  *	   ______________________4_
278  */
279 struct change_member {
280 	/* Pointer to the original entry: */
281 	struct e820_entry	*entry;
282 	/* Address for this change point: */
283 	unsigned long long	addr;
284 };
285 
286 static struct change_member	change_point_list[2*E820_MAX_ENTRIES]	__initdata;
287 static struct change_member	*change_point[2*E820_MAX_ENTRIES]	__initdata;
288 static struct e820_entry	*overlap_list[E820_MAX_ENTRIES]		__initdata;
289 static struct e820_entry	new_entries[E820_MAX_ENTRIES]		__initdata;
290 
cpcompare(const void * a,const void * b)291 static int __init cpcompare(const void *a, const void *b)
292 {
293 	struct change_member * const *app = a, * const *bpp = b;
294 	const struct change_member *ap = *app, *bp = *bpp;
295 
296 	/*
297 	 * Inputs are pointers to two elements of change_point[].  If their
298 	 * addresses are not equal, their difference dominates.  If the addresses
299 	 * are equal, then consider one that represents the end of its region
300 	 * to be greater than one that does not.
301 	 */
302 	if (ap->addr != bp->addr)
303 		return ap->addr > bp->addr ? 1 : -1;
304 
305 	return (ap->addr != ap->entry->addr) - (bp->addr != bp->entry->addr);
306 }
307 
e820_nomerge(enum e820_type type)308 static bool e820_nomerge(enum e820_type type)
309 {
310 	/*
311 	 * These types may indicate distinct platform ranges aligned to
312 	 * numa node, protection domain, performance domain, or other
313 	 * boundaries. Do not merge them.
314 	 */
315 	if (type == E820_TYPE_PRAM)
316 		return true;
317 	if (type == E820_TYPE_SOFT_RESERVED)
318 		return true;
319 	return false;
320 }
321 
e820__update_table(struct e820_table * table)322 int __init e820__update_table(struct e820_table *table)
323 {
324 	struct e820_entry *entries = table->entries;
325 	u32 max_nr_entries = ARRAY_SIZE(table->entries);
326 	enum e820_type current_type, last_type;
327 	unsigned long long last_addr;
328 	u32 new_nr_entries, overlap_entries;
329 	u32 i, chg_idx, chg_nr;
330 
331 	/* If there's only one memory region, don't bother: */
332 	if (table->nr_entries < 2)
333 		return -1;
334 
335 	BUG_ON(table->nr_entries > max_nr_entries);
336 
337 	/* Bail out if we find any unreasonable addresses in the map: */
338 	for (i = 0; i < table->nr_entries; i++) {
339 		if (entries[i].addr + entries[i].size < entries[i].addr)
340 			return -1;
341 	}
342 
343 	/* Create pointers for initial change-point information (for sorting): */
344 	for (i = 0; i < 2 * table->nr_entries; i++)
345 		change_point[i] = &change_point_list[i];
346 
347 	/*
348 	 * Record all known change-points (starting and ending addresses),
349 	 * omitting empty memory regions:
350 	 */
351 	chg_idx = 0;
352 	for (i = 0; i < table->nr_entries; i++)	{
353 		if (entries[i].size != 0) {
354 			change_point[chg_idx]->addr	= entries[i].addr;
355 			change_point[chg_idx++]->entry	= &entries[i];
356 			change_point[chg_idx]->addr	= entries[i].addr + entries[i].size;
357 			change_point[chg_idx++]->entry	= &entries[i];
358 		}
359 	}
360 	chg_nr = chg_idx;
361 
362 	/* Sort change-point list by memory addresses (low -> high): */
363 	sort(change_point, chg_nr, sizeof(*change_point), cpcompare, NULL);
364 
365 	/* Create a new memory map, removing overlaps: */
366 	overlap_entries = 0;	 /* Number of entries in the overlap table */
367 	new_nr_entries = 0;	 /* Index for creating new map entries */
368 	last_type = 0;		 /* Start with undefined memory type */
369 	last_addr = 0;		 /* Start with 0 as last starting address */
370 
371 	/* Loop through change-points, determining effect on the new map: */
372 	for (chg_idx = 0; chg_idx < chg_nr; chg_idx++) {
373 		/* Keep track of all overlapping entries */
374 		if (change_point[chg_idx]->addr == change_point[chg_idx]->entry->addr) {
375 			/* Add map entry to overlap list (> 1 entry implies an overlap) */
376 			overlap_list[overlap_entries++] = change_point[chg_idx]->entry;
377 		} else {
378 			/* Remove entry from list (order independent, so swap with last): */
379 			for (i = 0; i < overlap_entries; i++) {
380 				if (overlap_list[i] == change_point[chg_idx]->entry)
381 					overlap_list[i] = overlap_list[overlap_entries-1];
382 			}
383 			overlap_entries--;
384 		}
385 		/*
386 		 * If there are overlapping entries, decide which
387 		 * "type" to use (larger value takes precedence --
388 		 * 1=usable, 2,3,4,4+=unusable)
389 		 */
390 		current_type = 0;
391 		for (i = 0; i < overlap_entries; i++) {
392 			if (overlap_list[i]->type > current_type)
393 				current_type = overlap_list[i]->type;
394 		}
395 
396 		/* Continue building up new map based on this information: */
397 		if (current_type != last_type || e820_nomerge(current_type)) {
398 			if (last_type) {
399 				new_entries[new_nr_entries].size = change_point[chg_idx]->addr - last_addr;
400 				/* Move forward only if the new size was non-zero: */
401 				if (new_entries[new_nr_entries].size != 0)
402 					/* No more space left for new entries? */
403 					if (++new_nr_entries >= max_nr_entries)
404 						break;
405 			}
406 			if (current_type) {
407 				new_entries[new_nr_entries].addr = change_point[chg_idx]->addr;
408 				new_entries[new_nr_entries].type = current_type;
409 				last_addr = change_point[chg_idx]->addr;
410 			}
411 			last_type = current_type;
412 		}
413 	}
414 
415 	/* Copy the new entries into the original location: */
416 	memcpy(entries, new_entries, new_nr_entries*sizeof(*entries));
417 	table->nr_entries = new_nr_entries;
418 
419 	return 0;
420 }
421 
__append_e820_table(struct boot_e820_entry * entries,u32 nr_entries)422 static int __init __append_e820_table(struct boot_e820_entry *entries, u32 nr_entries)
423 {
424 	struct boot_e820_entry *entry = entries;
425 
426 	while (nr_entries) {
427 		u64 start = entry->addr;
428 		u64 size = entry->size;
429 		u64 end = start + size - 1;
430 		u32 type = entry->type;
431 
432 		/* Ignore the entry on 64-bit overflow: */
433 		if (start > end && likely(size))
434 			return -1;
435 
436 		e820__range_add(start, size, type);
437 
438 		entry++;
439 		nr_entries--;
440 	}
441 	return 0;
442 }
443 
444 /*
445  * Copy the BIOS E820 map into a safe place.
446  *
447  * Sanity-check it while we're at it..
448  *
449  * If we're lucky and live on a modern system, the setup code
450  * will have given us a memory map that we can use to properly
451  * set up memory.  If we aren't, we'll fake a memory map.
452  */
append_e820_table(struct boot_e820_entry * entries,u32 nr_entries)453 static int __init append_e820_table(struct boot_e820_entry *entries, u32 nr_entries)
454 {
455 	/* Only one memory region (or negative)? Ignore it */
456 	if (nr_entries < 2)
457 		return -1;
458 
459 	return __append_e820_table(entries, nr_entries);
460 }
461 
462 static u64 __init
__e820__range_update(struct e820_table * table,u64 start,u64 size,enum e820_type old_type,enum e820_type new_type)463 __e820__range_update(struct e820_table *table, u64 start, u64 size, enum e820_type old_type, enum e820_type new_type)
464 {
465 	u64 end;
466 	unsigned int i;
467 	u64 real_updated_size = 0;
468 
469 	BUG_ON(old_type == new_type);
470 
471 	if (size > (ULLONG_MAX - start))
472 		size = ULLONG_MAX - start;
473 
474 	end = start + size;
475 	printk(KERN_DEBUG "e820: update [mem %#010Lx-%#010Lx] ", start, end - 1);
476 	e820_print_type(old_type);
477 	pr_cont(" ==> ");
478 	e820_print_type(new_type);
479 	pr_cont("\n");
480 
481 	for (i = 0; i < table->nr_entries; i++) {
482 		struct e820_entry *entry = &table->entries[i];
483 		u64 final_start, final_end;
484 		u64 entry_end;
485 
486 		if (entry->type != old_type)
487 			continue;
488 
489 		entry_end = entry->addr + entry->size;
490 
491 		/* Completely covered by new range? */
492 		if (entry->addr >= start && entry_end <= end) {
493 			entry->type = new_type;
494 			real_updated_size += entry->size;
495 			continue;
496 		}
497 
498 		/* New range is completely covered? */
499 		if (entry->addr < start && entry_end > end) {
500 			__e820__range_add(table, start, size, new_type);
501 			__e820__range_add(table, end, entry_end - end, entry->type);
502 			entry->size = start - entry->addr;
503 			real_updated_size += size;
504 			continue;
505 		}
506 
507 		/* Partially covered: */
508 		final_start = max(start, entry->addr);
509 		final_end = min(end, entry_end);
510 		if (final_start >= final_end)
511 			continue;
512 
513 		__e820__range_add(table, final_start, final_end - final_start, new_type);
514 
515 		real_updated_size += final_end - final_start;
516 
517 		/*
518 		 * Left range could be head or tail, so need to update
519 		 * its size first:
520 		 */
521 		entry->size -= final_end - final_start;
522 		if (entry->addr < final_start)
523 			continue;
524 
525 		entry->addr = final_end;
526 	}
527 	return real_updated_size;
528 }
529 
e820__range_update(u64 start,u64 size,enum e820_type old_type,enum e820_type new_type)530 u64 __init e820__range_update(u64 start, u64 size, enum e820_type old_type, enum e820_type new_type)
531 {
532 	return __e820__range_update(e820_table, start, size, old_type, new_type);
533 }
534 
e820__range_update_kexec(u64 start,u64 size,enum e820_type old_type,enum e820_type new_type)535 static u64 __init e820__range_update_kexec(u64 start, u64 size, enum e820_type old_type, enum e820_type  new_type)
536 {
537 	return __e820__range_update(e820_table_kexec, start, size, old_type, new_type);
538 }
539 
540 /* Remove a range of memory from the E820 table: */
e820__range_remove(u64 start,u64 size,enum e820_type old_type,bool check_type)541 u64 __init e820__range_remove(u64 start, u64 size, enum e820_type old_type, bool check_type)
542 {
543 	int i;
544 	u64 end;
545 	u64 real_removed_size = 0;
546 
547 	if (size > (ULLONG_MAX - start))
548 		size = ULLONG_MAX - start;
549 
550 	end = start + size;
551 	printk(KERN_DEBUG "e820: remove [mem %#010Lx-%#010Lx] ", start, end - 1);
552 	if (check_type)
553 		e820_print_type(old_type);
554 	pr_cont("\n");
555 
556 	for (i = 0; i < e820_table->nr_entries; i++) {
557 		struct e820_entry *entry = &e820_table->entries[i];
558 		u64 final_start, final_end;
559 		u64 entry_end;
560 
561 		if (check_type && entry->type != old_type)
562 			continue;
563 
564 		entry_end = entry->addr + entry->size;
565 
566 		/* Completely covered? */
567 		if (entry->addr >= start && entry_end <= end) {
568 			real_removed_size += entry->size;
569 			memset(entry, 0, sizeof(*entry));
570 			continue;
571 		}
572 
573 		/* Is the new range completely covered? */
574 		if (entry->addr < start && entry_end > end) {
575 			e820__range_add(end, entry_end - end, entry->type);
576 			entry->size = start - entry->addr;
577 			real_removed_size += size;
578 			continue;
579 		}
580 
581 		/* Partially covered: */
582 		final_start = max(start, entry->addr);
583 		final_end = min(end, entry_end);
584 		if (final_start >= final_end)
585 			continue;
586 
587 		real_removed_size += final_end - final_start;
588 
589 		/*
590 		 * Left range could be head or tail, so need to update
591 		 * the size first:
592 		 */
593 		entry->size -= final_end - final_start;
594 		if (entry->addr < final_start)
595 			continue;
596 
597 		entry->addr = final_end;
598 	}
599 	return real_removed_size;
600 }
601 
e820__update_table_print(void)602 void __init e820__update_table_print(void)
603 {
604 	if (e820__update_table(e820_table))
605 		return;
606 
607 	pr_info("modified physical RAM map:\n");
608 	e820__print_table("modified");
609 }
610 
e820__update_table_kexec(void)611 static void __init e820__update_table_kexec(void)
612 {
613 	e820__update_table(e820_table_kexec);
614 }
615 
616 #define MAX_GAP_END 0x100000000ull
617 
618 /*
619  * Search for a gap in the E820 memory space from 0 to MAX_GAP_END (4GB).
620  */
e820_search_gap(unsigned long * gapstart,unsigned long * gapsize)621 static int __init e820_search_gap(unsigned long *gapstart, unsigned long *gapsize)
622 {
623 	unsigned long long last = MAX_GAP_END;
624 	int i = e820_table->nr_entries;
625 	int found = 0;
626 
627 	while (--i >= 0) {
628 		unsigned long long start = e820_table->entries[i].addr;
629 		unsigned long long end = start + e820_table->entries[i].size;
630 
631 		/*
632 		 * Since "last" is at most 4GB, we know we'll
633 		 * fit in 32 bits if this condition is true:
634 		 */
635 		if (last > end) {
636 			unsigned long gap = last - end;
637 
638 			if (gap >= *gapsize) {
639 				*gapsize = gap;
640 				*gapstart = end;
641 				found = 1;
642 			}
643 		}
644 		if (start < last)
645 			last = start;
646 	}
647 	return found;
648 }
649 
650 /*
651  * Search for the biggest gap in the low 32 bits of the E820
652  * memory space. We pass this space to the PCI subsystem, so
653  * that it can assign MMIO resources for hotplug or
654  * unconfigured devices in.
655  *
656  * Hopefully the BIOS let enough space left.
657  */
e820__setup_pci_gap(void)658 __init void e820__setup_pci_gap(void)
659 {
660 	unsigned long gapstart, gapsize;
661 	int found;
662 
663 	gapsize = 0x400000;
664 	found  = e820_search_gap(&gapstart, &gapsize);
665 
666 	if (!found) {
667 #ifdef CONFIG_X86_64
668 		gapstart = (max_pfn << PAGE_SHIFT) + 1024*1024;
669 		pr_err("Cannot find an available gap in the 32-bit address range\n");
670 		pr_err("PCI devices with unassigned 32-bit BARs may not work!\n");
671 #else
672 		gapstart = 0x10000000;
673 #endif
674 	}
675 
676 	/*
677 	 * e820__reserve_resources_late() protects stolen RAM already:
678 	 */
679 	pci_mem_start = gapstart;
680 
681 	pr_info("[mem %#010lx-%#010lx] available for PCI devices\n",
682 		gapstart, gapstart + gapsize - 1);
683 }
684 
685 /*
686  * Called late during init, in free_initmem().
687  *
688  * Initial e820_table and e820_table_kexec are largish __initdata arrays.
689  *
690  * Copy them to a (usually much smaller) dynamically allocated area that is
691  * sized precisely after the number of e820 entries.
692  *
693  * This is done after we've performed all the fixes and tweaks to the tables.
694  * All functions which modify them are __init functions, which won't exist
695  * after free_initmem().
696  */
e820__reallocate_tables(void)697 __init void e820__reallocate_tables(void)
698 {
699 	struct e820_table *n;
700 	int size;
701 
702 	size = offsetof(struct e820_table, entries) + sizeof(struct e820_entry)*e820_table->nr_entries;
703 	n = kmemdup(e820_table, size, GFP_KERNEL);
704 	BUG_ON(!n);
705 	e820_table = n;
706 
707 	size = offsetof(struct e820_table, entries) + sizeof(struct e820_entry)*e820_table_kexec->nr_entries;
708 	n = kmemdup(e820_table_kexec, size, GFP_KERNEL);
709 	BUG_ON(!n);
710 	e820_table_kexec = n;
711 
712 	size = offsetof(struct e820_table, entries) + sizeof(struct e820_entry)*e820_table_firmware->nr_entries;
713 	n = kmemdup(e820_table_firmware, size, GFP_KERNEL);
714 	BUG_ON(!n);
715 	e820_table_firmware = n;
716 }
717 
718 /*
719  * Because of the small fixed size of struct boot_params, only the first
720  * 128 E820 memory entries are passed to the kernel via boot_params.e820_table,
721  * the remaining (if any) entries are passed via the SETUP_E820_EXT node of
722  * struct setup_data, which is parsed here.
723  */
e820__memory_setup_extended(u64 phys_addr,u32 data_len)724 void __init e820__memory_setup_extended(u64 phys_addr, u32 data_len)
725 {
726 	int entries;
727 	struct boot_e820_entry *extmap;
728 	struct setup_data *sdata;
729 
730 	sdata = early_memremap(phys_addr, data_len);
731 	entries = sdata->len / sizeof(*extmap);
732 	extmap = (struct boot_e820_entry *)(sdata->data);
733 
734 	__append_e820_table(extmap, entries);
735 	e820__update_table(e820_table);
736 
737 	memcpy(e820_table_kexec, e820_table, sizeof(*e820_table_kexec));
738 	memcpy(e820_table_firmware, e820_table, sizeof(*e820_table_firmware));
739 
740 	early_memunmap(sdata, data_len);
741 	pr_info("extended physical RAM map:\n");
742 	e820__print_table("extended");
743 }
744 
745 /*
746  * Find the ranges of physical addresses that do not correspond to
747  * E820 RAM areas and register the corresponding pages as 'nosave' for
748  * hibernation (32-bit) or software suspend and suspend to RAM (64-bit).
749  *
750  * This function requires the E820 map to be sorted and without any
751  * overlapping entries.
752  */
e820__register_nosave_regions(unsigned long limit_pfn)753 void __init e820__register_nosave_regions(unsigned long limit_pfn)
754 {
755 	int i;
756 	unsigned long pfn = 0;
757 
758 	for (i = 0; i < e820_table->nr_entries; i++) {
759 		struct e820_entry *entry = &e820_table->entries[i];
760 
761 		if (pfn < PFN_UP(entry->addr))
762 			register_nosave_region(pfn, PFN_UP(entry->addr));
763 
764 		pfn = PFN_DOWN(entry->addr + entry->size);
765 
766 		if (entry->type != E820_TYPE_RAM && entry->type != E820_TYPE_RESERVED_KERN)
767 			register_nosave_region(PFN_UP(entry->addr), pfn);
768 
769 		if (pfn >= limit_pfn)
770 			break;
771 	}
772 }
773 
774 #ifdef CONFIG_ACPI
775 /*
776  * Register ACPI NVS memory regions, so that we can save/restore them during
777  * hibernation and the subsequent resume:
778  */
e820__register_nvs_regions(void)779 static int __init e820__register_nvs_regions(void)
780 {
781 	int i;
782 
783 	for (i = 0; i < e820_table->nr_entries; i++) {
784 		struct e820_entry *entry = &e820_table->entries[i];
785 
786 		if (entry->type == E820_TYPE_NVS)
787 			acpi_nvs_register(entry->addr, entry->size);
788 	}
789 
790 	return 0;
791 }
792 core_initcall(e820__register_nvs_regions);
793 #endif
794 
795 /*
796  * Allocate the requested number of bytes with the requested alignment
797  * and return (the physical address) to the caller. Also register this
798  * range in the 'kexec' E820 table as a reserved range.
799  *
800  * This allows kexec to fake a new mptable, as if it came from the real
801  * system.
802  */
e820__memblock_alloc_reserved(u64 size,u64 align)803 u64 __init e820__memblock_alloc_reserved(u64 size, u64 align)
804 {
805 	u64 addr;
806 
807 	addr = memblock_phys_alloc(size, align);
808 	if (addr) {
809 		e820__range_update_kexec(addr, size, E820_TYPE_RAM, E820_TYPE_RESERVED);
810 		pr_info("update e820_table_kexec for e820__memblock_alloc_reserved()\n");
811 		e820__update_table_kexec();
812 	}
813 
814 	return addr;
815 }
816 
817 #ifdef CONFIG_X86_32
818 # ifdef CONFIG_X86_PAE
819 #  define MAX_ARCH_PFN		(1ULL<<(36-PAGE_SHIFT))
820 # else
821 #  define MAX_ARCH_PFN		(1ULL<<(32-PAGE_SHIFT))
822 # endif
823 #else /* CONFIG_X86_32 */
824 # define MAX_ARCH_PFN MAXMEM>>PAGE_SHIFT
825 #endif
826 
827 /*
828  * Find the highest page frame number we have available
829  */
e820_end_pfn(unsigned long limit_pfn,enum e820_type type)830 static unsigned long __init e820_end_pfn(unsigned long limit_pfn, enum e820_type type)
831 {
832 	int i;
833 	unsigned long last_pfn = 0;
834 	unsigned long max_arch_pfn = MAX_ARCH_PFN;
835 
836 	for (i = 0; i < e820_table->nr_entries; i++) {
837 		struct e820_entry *entry = &e820_table->entries[i];
838 		unsigned long start_pfn;
839 		unsigned long end_pfn;
840 
841 		if (entry->type != type)
842 			continue;
843 
844 		start_pfn = entry->addr >> PAGE_SHIFT;
845 		end_pfn = (entry->addr + entry->size) >> PAGE_SHIFT;
846 
847 		if (start_pfn >= limit_pfn)
848 			continue;
849 		if (end_pfn > limit_pfn) {
850 			last_pfn = limit_pfn;
851 			break;
852 		}
853 		if (end_pfn > last_pfn)
854 			last_pfn = end_pfn;
855 	}
856 
857 	if (last_pfn > max_arch_pfn)
858 		last_pfn = max_arch_pfn;
859 
860 	pr_info("last_pfn = %#lx max_arch_pfn = %#lx\n",
861 		last_pfn, max_arch_pfn);
862 	return last_pfn;
863 }
864 
e820__end_of_ram_pfn(void)865 unsigned long __init e820__end_of_ram_pfn(void)
866 {
867 	return e820_end_pfn(MAX_ARCH_PFN, E820_TYPE_RAM);
868 }
869 
e820__end_of_low_ram_pfn(void)870 unsigned long __init e820__end_of_low_ram_pfn(void)
871 {
872 	return e820_end_pfn(1UL << (32 - PAGE_SHIFT), E820_TYPE_RAM);
873 }
874 
early_panic(char * msg)875 static void __init early_panic(char *msg)
876 {
877 	early_printk(msg);
878 	panic(msg);
879 }
880 
881 static int userdef __initdata;
882 
883 /* The "mem=nopentium" boot option disables 4MB page tables on 32-bit kernels: */
parse_memopt(char * p)884 static int __init parse_memopt(char *p)
885 {
886 	u64 mem_size;
887 
888 	if (!p)
889 		return -EINVAL;
890 
891 	if (!strcmp(p, "nopentium")) {
892 #ifdef CONFIG_X86_32
893 		setup_clear_cpu_cap(X86_FEATURE_PSE);
894 		return 0;
895 #else
896 		pr_warn("mem=nopentium ignored! (only supported on x86_32)\n");
897 		return -EINVAL;
898 #endif
899 	}
900 
901 	userdef = 1;
902 	mem_size = memparse(p, &p);
903 
904 	/* Don't remove all memory when getting "mem={invalid}" parameter: */
905 	if (mem_size == 0)
906 		return -EINVAL;
907 
908 	e820__range_remove(mem_size, ULLONG_MAX - mem_size, E820_TYPE_RAM, 1);
909 
910 #ifdef CONFIG_MEMORY_HOTPLUG
911 	max_mem_size = mem_size;
912 #endif
913 
914 	return 0;
915 }
916 early_param("mem", parse_memopt);
917 
parse_memmap_one(char * p)918 static int __init parse_memmap_one(char *p)
919 {
920 	char *oldp;
921 	u64 start_at, mem_size;
922 
923 	if (!p)
924 		return -EINVAL;
925 
926 	if (!strncmp(p, "exactmap", 8)) {
927 		e820_table->nr_entries = 0;
928 		userdef = 1;
929 		return 0;
930 	}
931 
932 	oldp = p;
933 	mem_size = memparse(p, &p);
934 	if (p == oldp)
935 		return -EINVAL;
936 
937 	userdef = 1;
938 	if (*p == '@') {
939 		start_at = memparse(p+1, &p);
940 		e820__range_add(start_at, mem_size, E820_TYPE_RAM);
941 	} else if (*p == '#') {
942 		start_at = memparse(p+1, &p);
943 		e820__range_add(start_at, mem_size, E820_TYPE_ACPI);
944 	} else if (*p == '$') {
945 		start_at = memparse(p+1, &p);
946 		e820__range_add(start_at, mem_size, E820_TYPE_RESERVED);
947 	} else if (*p == '!') {
948 		start_at = memparse(p+1, &p);
949 		e820__range_add(start_at, mem_size, E820_TYPE_PRAM);
950 	} else if (*p == '%') {
951 		enum e820_type from = 0, to = 0;
952 
953 		start_at = memparse(p + 1, &p);
954 		if (*p == '-')
955 			from = simple_strtoull(p + 1, &p, 0);
956 		if (*p == '+')
957 			to = simple_strtoull(p + 1, &p, 0);
958 		if (*p != '\0')
959 			return -EINVAL;
960 		if (from && to)
961 			e820__range_update(start_at, mem_size, from, to);
962 		else if (to)
963 			e820__range_add(start_at, mem_size, to);
964 		else if (from)
965 			e820__range_remove(start_at, mem_size, from, 1);
966 		else
967 			e820__range_remove(start_at, mem_size, 0, 0);
968 	} else {
969 		e820__range_remove(mem_size, ULLONG_MAX - mem_size, E820_TYPE_RAM, 1);
970 	}
971 
972 	return *p == '\0' ? 0 : -EINVAL;
973 }
974 
parse_memmap_opt(char * str)975 static int __init parse_memmap_opt(char *str)
976 {
977 	while (str) {
978 		char *k = strchr(str, ',');
979 
980 		if (k)
981 			*k++ = 0;
982 
983 		parse_memmap_one(str);
984 		str = k;
985 	}
986 
987 	return 0;
988 }
989 early_param("memmap", parse_memmap_opt);
990 
991 /*
992  * Reserve all entries from the bootloader's extensible data nodes list,
993  * because if present we are going to use it later on to fetch e820
994  * entries from it:
995  */
e820__reserve_setup_data(void)996 void __init e820__reserve_setup_data(void)
997 {
998 	struct setup_indirect *indirect;
999 	struct setup_data *data;
1000 	u64 pa_data, pa_next;
1001 	u32 len;
1002 
1003 	pa_data = boot_params.hdr.setup_data;
1004 	if (!pa_data)
1005 		return;
1006 
1007 	while (pa_data) {
1008 		data = early_memremap(pa_data, sizeof(*data));
1009 		if (!data) {
1010 			pr_warn("e820: failed to memremap setup_data entry\n");
1011 			return;
1012 		}
1013 
1014 		len = sizeof(*data);
1015 		pa_next = data->next;
1016 
1017 		e820__range_update(pa_data, sizeof(*data)+data->len, E820_TYPE_RAM, E820_TYPE_RESERVED_KERN);
1018 
1019 		/*
1020 		 * SETUP_EFI, SETUP_IMA and SETUP_RNG_SEED are supplied by
1021 		 * kexec and do not need to be reserved.
1022 		 */
1023 		if (data->type != SETUP_EFI &&
1024 		    data->type != SETUP_IMA &&
1025 		    data->type != SETUP_RNG_SEED)
1026 			e820__range_update_kexec(pa_data,
1027 						 sizeof(*data) + data->len,
1028 						 E820_TYPE_RAM, E820_TYPE_RESERVED_KERN);
1029 
1030 		if (data->type == SETUP_INDIRECT) {
1031 			len += data->len;
1032 			early_memunmap(data, sizeof(*data));
1033 			data = early_memremap(pa_data, len);
1034 			if (!data) {
1035 				pr_warn("e820: failed to memremap indirect setup_data\n");
1036 				return;
1037 			}
1038 
1039 			indirect = (struct setup_indirect *)data->data;
1040 
1041 			if (indirect->type != SETUP_INDIRECT) {
1042 				e820__range_update(indirect->addr, indirect->len,
1043 						   E820_TYPE_RAM, E820_TYPE_RESERVED_KERN);
1044 				e820__range_update_kexec(indirect->addr, indirect->len,
1045 							 E820_TYPE_RAM, E820_TYPE_RESERVED_KERN);
1046 			}
1047 		}
1048 
1049 		pa_data = pa_next;
1050 		early_memunmap(data, len);
1051 	}
1052 
1053 	e820__update_table(e820_table);
1054 	e820__update_table(e820_table_kexec);
1055 
1056 	pr_info("extended physical RAM map:\n");
1057 	e820__print_table("reserve setup_data");
1058 }
1059 
1060 /*
1061  * Called after parse_early_param(), after early parameters (such as mem=)
1062  * have been processed, in which case we already have an E820 table filled in
1063  * via the parameter callback function(s), but it's not sorted and printed yet:
1064  */
e820__finish_early_params(void)1065 void __init e820__finish_early_params(void)
1066 {
1067 	if (userdef) {
1068 		if (e820__update_table(e820_table) < 0)
1069 			early_panic("Invalid user supplied memory map");
1070 
1071 		pr_info("user-defined physical RAM map:\n");
1072 		e820__print_table("user");
1073 	}
1074 }
1075 
e820_type_to_string(struct e820_entry * entry)1076 static const char *__init e820_type_to_string(struct e820_entry *entry)
1077 {
1078 	switch (entry->type) {
1079 	case E820_TYPE_RESERVED_KERN:	/* Fall-through: */
1080 	case E820_TYPE_RAM:		return "System RAM";
1081 	case E820_TYPE_ACPI:		return "ACPI Tables";
1082 	case E820_TYPE_NVS:		return "ACPI Non-volatile Storage";
1083 	case E820_TYPE_UNUSABLE:	return "Unusable memory";
1084 	case E820_TYPE_PRAM:		return "Persistent Memory (legacy)";
1085 	case E820_TYPE_PMEM:		return "Persistent Memory";
1086 	case E820_TYPE_RESERVED:	return "Reserved";
1087 	case E820_TYPE_SOFT_RESERVED:	return "Soft Reserved";
1088 	default:			return "Unknown E820 type";
1089 	}
1090 }
1091 
e820_type_to_iomem_type(struct e820_entry * entry)1092 static unsigned long __init e820_type_to_iomem_type(struct e820_entry *entry)
1093 {
1094 	switch (entry->type) {
1095 	case E820_TYPE_RESERVED_KERN:	/* Fall-through: */
1096 	case E820_TYPE_RAM:		return IORESOURCE_SYSTEM_RAM;
1097 	case E820_TYPE_ACPI:		/* Fall-through: */
1098 	case E820_TYPE_NVS:		/* Fall-through: */
1099 	case E820_TYPE_UNUSABLE:	/* Fall-through: */
1100 	case E820_TYPE_PRAM:		/* Fall-through: */
1101 	case E820_TYPE_PMEM:		/* Fall-through: */
1102 	case E820_TYPE_RESERVED:	/* Fall-through: */
1103 	case E820_TYPE_SOFT_RESERVED:	/* Fall-through: */
1104 	default:			return IORESOURCE_MEM;
1105 	}
1106 }
1107 
e820_type_to_iores_desc(struct e820_entry * entry)1108 static unsigned long __init e820_type_to_iores_desc(struct e820_entry *entry)
1109 {
1110 	switch (entry->type) {
1111 	case E820_TYPE_ACPI:		return IORES_DESC_ACPI_TABLES;
1112 	case E820_TYPE_NVS:		return IORES_DESC_ACPI_NV_STORAGE;
1113 	case E820_TYPE_PMEM:		return IORES_DESC_PERSISTENT_MEMORY;
1114 	case E820_TYPE_PRAM:		return IORES_DESC_PERSISTENT_MEMORY_LEGACY;
1115 	case E820_TYPE_RESERVED:	return IORES_DESC_RESERVED;
1116 	case E820_TYPE_SOFT_RESERVED:	return IORES_DESC_SOFT_RESERVED;
1117 	case E820_TYPE_RESERVED_KERN:	/* Fall-through: */
1118 	case E820_TYPE_RAM:		/* Fall-through: */
1119 	case E820_TYPE_UNUSABLE:	/* Fall-through: */
1120 	default:			return IORES_DESC_NONE;
1121 	}
1122 }
1123 
do_mark_busy(enum e820_type type,struct resource * res)1124 static bool __init do_mark_busy(enum e820_type type, struct resource *res)
1125 {
1126 	/* this is the legacy bios/dos rom-shadow + mmio region */
1127 	if (res->start < (1ULL<<20))
1128 		return true;
1129 
1130 	/*
1131 	 * Treat persistent memory and other special memory ranges like
1132 	 * device memory, i.e. reserve it for exclusive use of a driver
1133 	 */
1134 	switch (type) {
1135 	case E820_TYPE_RESERVED:
1136 	case E820_TYPE_SOFT_RESERVED:
1137 	case E820_TYPE_PRAM:
1138 	case E820_TYPE_PMEM:
1139 		return false;
1140 	case E820_TYPE_RESERVED_KERN:
1141 	case E820_TYPE_RAM:
1142 	case E820_TYPE_ACPI:
1143 	case E820_TYPE_NVS:
1144 	case E820_TYPE_UNUSABLE:
1145 	default:
1146 		return true;
1147 	}
1148 }
1149 
1150 /*
1151  * Mark E820 reserved areas as busy for the resource manager:
1152  */
1153 
1154 static struct resource __initdata *e820_res;
1155 
e820__reserve_resources(void)1156 void __init e820__reserve_resources(void)
1157 {
1158 	int i;
1159 	struct resource *res;
1160 	u64 end;
1161 
1162 	res = memblock_alloc(sizeof(*res) * e820_table->nr_entries,
1163 			     SMP_CACHE_BYTES);
1164 	if (!res)
1165 		panic("%s: Failed to allocate %zu bytes\n", __func__,
1166 		      sizeof(*res) * e820_table->nr_entries);
1167 	e820_res = res;
1168 
1169 	for (i = 0; i < e820_table->nr_entries; i++) {
1170 		struct e820_entry *entry = e820_table->entries + i;
1171 
1172 		end = entry->addr + entry->size - 1;
1173 		if (end != (resource_size_t)end) {
1174 			res++;
1175 			continue;
1176 		}
1177 		res->start = entry->addr;
1178 		res->end   = end;
1179 		res->name  = e820_type_to_string(entry);
1180 		res->flags = e820_type_to_iomem_type(entry);
1181 		res->desc  = e820_type_to_iores_desc(entry);
1182 
1183 		/*
1184 		 * Don't register the region that could be conflicted with
1185 		 * PCI device BAR resources and insert them later in
1186 		 * pcibios_resource_survey():
1187 		 */
1188 		if (do_mark_busy(entry->type, res)) {
1189 			res->flags |= IORESOURCE_BUSY;
1190 			insert_resource(&iomem_resource, res);
1191 		}
1192 		res++;
1193 	}
1194 
1195 	/* Expose the bootloader-provided memory layout to the sysfs. */
1196 	for (i = 0; i < e820_table_firmware->nr_entries; i++) {
1197 		struct e820_entry *entry = e820_table_firmware->entries + i;
1198 
1199 		firmware_map_add_early(entry->addr, entry->addr + entry->size, e820_type_to_string(entry));
1200 	}
1201 }
1202 
1203 /*
1204  * How much should we pad the end of RAM, depending on where it is?
1205  */
ram_alignment(resource_size_t pos)1206 static unsigned long __init ram_alignment(resource_size_t pos)
1207 {
1208 	unsigned long mb = pos >> 20;
1209 
1210 	/* To 64kB in the first megabyte */
1211 	if (!mb)
1212 		return 64*1024;
1213 
1214 	/* To 1MB in the first 16MB */
1215 	if (mb < 16)
1216 		return 1024*1024;
1217 
1218 	/* To 64MB for anything above that */
1219 	return 64*1024*1024;
1220 }
1221 
1222 #define MAX_RESOURCE_SIZE ((resource_size_t)-1)
1223 
e820__reserve_resources_late(void)1224 void __init e820__reserve_resources_late(void)
1225 {
1226 	int i;
1227 	struct resource *res;
1228 
1229 	res = e820_res;
1230 	for (i = 0; i < e820_table->nr_entries; i++) {
1231 		if (!res->parent && res->end)
1232 			insert_resource_expand_to_fit(&iomem_resource, res);
1233 		res++;
1234 	}
1235 
1236 	/*
1237 	 * Try to bump up RAM regions to reasonable boundaries, to
1238 	 * avoid stolen RAM:
1239 	 */
1240 	for (i = 0; i < e820_table->nr_entries; i++) {
1241 		struct e820_entry *entry = &e820_table->entries[i];
1242 		u64 start, end;
1243 
1244 		if (entry->type != E820_TYPE_RAM)
1245 			continue;
1246 
1247 		start = entry->addr + entry->size;
1248 		end = round_up(start, ram_alignment(start)) - 1;
1249 		if (end > MAX_RESOURCE_SIZE)
1250 			end = MAX_RESOURCE_SIZE;
1251 		if (start >= end)
1252 			continue;
1253 
1254 		printk(KERN_DEBUG "e820: reserve RAM buffer [mem %#010llx-%#010llx]\n", start, end);
1255 		reserve_region_with_split(&iomem_resource, start, end, "RAM buffer");
1256 	}
1257 }
1258 
1259 /*
1260  * Pass the firmware (bootloader) E820 map to the kernel and process it:
1261  */
e820__memory_setup_default(void)1262 char *__init e820__memory_setup_default(void)
1263 {
1264 	char *who = "BIOS-e820";
1265 
1266 	/*
1267 	 * Try to copy the BIOS-supplied E820-map.
1268 	 *
1269 	 * Otherwise fake a memory map; one section from 0k->640k,
1270 	 * the next section from 1mb->appropriate_mem_k
1271 	 */
1272 	if (append_e820_table(boot_params.e820_table, boot_params.e820_entries) < 0) {
1273 		u64 mem_size;
1274 
1275 		/* Compare results from other methods and take the one that gives more RAM: */
1276 		if (boot_params.alt_mem_k < boot_params.screen_info.ext_mem_k) {
1277 			mem_size = boot_params.screen_info.ext_mem_k;
1278 			who = "BIOS-88";
1279 		} else {
1280 			mem_size = boot_params.alt_mem_k;
1281 			who = "BIOS-e801";
1282 		}
1283 
1284 		e820_table->nr_entries = 0;
1285 		e820__range_add(0, LOWMEMSIZE(), E820_TYPE_RAM);
1286 		e820__range_add(HIGH_MEMORY, mem_size << 10, E820_TYPE_RAM);
1287 	}
1288 
1289 	/* We just appended a lot of ranges, sanitize the table: */
1290 	e820__update_table(e820_table);
1291 
1292 	return who;
1293 }
1294 
1295 /*
1296  * Calls e820__memory_setup_default() in essence to pick up the firmware/bootloader
1297  * E820 map - with an optional platform quirk available for virtual platforms
1298  * to override this method of boot environment processing:
1299  */
e820__memory_setup(void)1300 void __init e820__memory_setup(void)
1301 {
1302 	char *who;
1303 
1304 	/* This is a firmware interface ABI - make sure we don't break it: */
1305 	BUILD_BUG_ON(sizeof(struct boot_e820_entry) != 20);
1306 
1307 	who = x86_init.resources.memory_setup();
1308 
1309 	memcpy(e820_table_kexec, e820_table, sizeof(*e820_table_kexec));
1310 	memcpy(e820_table_firmware, e820_table, sizeof(*e820_table_firmware));
1311 
1312 	pr_info("BIOS-provided physical RAM map:\n");
1313 	e820__print_table(who);
1314 }
1315 
e820__memblock_setup(void)1316 void __init e820__memblock_setup(void)
1317 {
1318 	int i;
1319 	u64 end;
1320 
1321 	/*
1322 	 * The bootstrap memblock region count maximum is 128 entries
1323 	 * (INIT_MEMBLOCK_REGIONS), but EFI might pass us more E820 entries
1324 	 * than that - so allow memblock resizing.
1325 	 *
1326 	 * This is safe, because this call happens pretty late during x86 setup,
1327 	 * so we know about reserved memory regions already. (This is important
1328 	 * so that memblock resizing does no stomp over reserved areas.)
1329 	 */
1330 	memblock_allow_resize();
1331 
1332 	for (i = 0; i < e820_table->nr_entries; i++) {
1333 		struct e820_entry *entry = &e820_table->entries[i];
1334 
1335 		end = entry->addr + entry->size;
1336 		if (end != (resource_size_t)end)
1337 			continue;
1338 
1339 		if (entry->type == E820_TYPE_SOFT_RESERVED)
1340 			memblock_reserve(entry->addr, entry->size);
1341 
1342 		if (entry->type != E820_TYPE_RAM && entry->type != E820_TYPE_RESERVED_KERN)
1343 			continue;
1344 
1345 		memblock_add(entry->addr, entry->size);
1346 	}
1347 
1348 	/* Throw away partial pages: */
1349 	memblock_trim_memory(PAGE_SIZE);
1350 
1351 	memblock_dump_all();
1352 }
1353