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TOMOYO Linux Cross Reference
Linux/arch/x86/kernel/e820.c

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  1 /*
  2  * Low level x86 E820 memory map handling functions.
  3  *
  4  * The firmware and bootloader passes us the "E820 table", which is the primary
  5  * physical memory layout description available about x86 systems.
  6  *
  7  * The kernel takes the E820 memory layout and optionally modifies it with
  8  * quirks and other tweaks, and feeds that into the generic Linux memory
  9  * allocation code routines via a platform independent interface (memblock, etc.).
 10  */
 11 #include <linux/crash_dump.h>
 12 #include <linux/bootmem.h>
 13 #include <linux/suspend.h>
 14 #include <linux/acpi.h>
 15 #include <linux/firmware-map.h>
 16 #include <linux/memblock.h>
 17 #include <linux/sort.h>
 18 
 19 #include <asm/e820/api.h>
 20 #include <asm/setup.h>
 21 
 22 /*
 23  * We organize the E820 table into three main data structures:
 24  *
 25  * - 'e820_table_firmware': the original firmware version passed to us by the
 26  *   bootloader - not modified by the kernel. It is composed of two parts:
 27  *   the first 128 E820 memory entries in boot_params.e820_table and the remaining
 28  *   (if any) entries of the SETUP_E820_EXT nodes. We use this to:
 29  *
 30  *       - inform the user about the firmware's notion of memory layout
 31  *         via /sys/firmware/memmap
 32  *
 33  *       - the hibernation code uses it to generate a kernel-independent MD5
 34  *         fingerprint of the physical memory layout of a system.
 35  *
 36  * - 'e820_table_kexec': a slightly modified (by the kernel) firmware version
 37  *   passed to us by the bootloader - the major difference between
 38  *   e820_table_firmware[] and this one is that, the latter marks the setup_data
 39  *   list created by the EFI boot stub as reserved, so that kexec can reuse the
 40  *   setup_data information in the second kernel. Besides, e820_table_kexec[]
 41  *   might also be modified by the kexec itself to fake a mptable.
 42  *   We use this to:
 43  *
 44  *       - kexec, which is a bootloader in disguise, uses the original E820
 45  *         layout to pass to the kexec-ed kernel. This way the original kernel
 46  *         can have a restricted E820 map while the kexec()-ed kexec-kernel
 47  *         can have access to full memory - etc.
 48  *
 49  * - 'e820_table': this is the main E820 table that is massaged by the
 50  *   low level x86 platform code, or modified by boot parameters, before
 51  *   passed on to higher level MM layers.
 52  *
 53  * Once the E820 map has been converted to the standard Linux memory layout
 54  * information its role stops - modifying it has no effect and does not get
 55  * re-propagated. So itsmain role is a temporary bootstrap storage of firmware
 56  * specific memory layout data during early bootup.
 57  */
 58 static struct e820_table e820_table_init                __initdata;
 59 static struct e820_table e820_table_kexec_init          __initdata;
 60 static struct e820_table e820_table_firmware_init       __initdata;
 61 
 62 struct e820_table *e820_table __refdata                 = &e820_table_init;
 63 struct e820_table *e820_table_kexec __refdata           = &e820_table_kexec_init;
 64 struct e820_table *e820_table_firmware __refdata        = &e820_table_firmware_init;
 65 
 66 /* For PCI or other memory-mapped resources */
 67 unsigned long pci_mem_start = 0xaeedbabe;
 68 #ifdef CONFIG_PCI
 69 EXPORT_SYMBOL(pci_mem_start);
 70 #endif
 71 
 72 /*
 73  * This function checks if any part of the range <start,end> is mapped
 74  * with type.
 75  */
 76 bool e820__mapped_any(u64 start, u64 end, enum e820_type type)
 77 {
 78         int i;
 79 
 80         for (i = 0; i < e820_table->nr_entries; i++) {
 81                 struct e820_entry *entry = &e820_table->entries[i];
 82 
 83                 if (type && entry->type != type)
 84                         continue;
 85                 if (entry->addr >= end || entry->addr + entry->size <= start)
 86                         continue;
 87                 return 1;
 88         }
 89         return 0;
 90 }
 91 EXPORT_SYMBOL_GPL(e820__mapped_any);
 92 
 93 /*
 94  * This function checks if the entire <start,end> range is mapped with 'type'.
 95  *
 96  * Note: this function only works correctly once the E820 table is sorted and
 97  * not-overlapping (at least for the range specified), which is the case normally.
 98  */
 99 static struct e820_entry *__e820__mapped_all(u64 start, u64 end,
100                                              enum e820_type type)
101 {
102         int i;
103 
104         for (i = 0; i < e820_table->nr_entries; i++) {
105                 struct e820_entry *entry = &e820_table->entries[i];
106 
107                 if (type && entry->type != type)
108                         continue;
109 
110                 /* Is the region (part) in overlap with the current region? */
111                 if (entry->addr >= end || entry->addr + entry->size <= start)
112                         continue;
113 
114                 /*
115                  * If the region is at the beginning of <start,end> we move
116                  * 'start' to the end of the region since it's ok until there
117                  */
118                 if (entry->addr <= start)
119                         start = entry->addr + entry->size;
120 
121                 /*
122                  * If 'start' is now at or beyond 'end', we're done, full
123                  * coverage of the desired range exists:
124                  */
125                 if (start >= end)
126                         return entry;
127         }
128 
129         return NULL;
130 }
131 
132 /*
133  * This function checks if the entire range <start,end> is mapped with type.
134  */
135 bool __init e820__mapped_all(u64 start, u64 end, enum e820_type type)
136 {
137         return __e820__mapped_all(start, end, type);
138 }
139 
140 /*
141  * This function returns the type associated with the range <start,end>.
142  */
143 int e820__get_entry_type(u64 start, u64 end)
144 {
145         struct e820_entry *entry = __e820__mapped_all(start, end, 0);
146 
147         return entry ? entry->type : -EINVAL;
148 }
149 
150 /*
151  * Add a memory region to the kernel E820 map.
152  */
153 static void __init __e820__range_add(struct e820_table *table, u64 start, u64 size, enum e820_type type)
154 {
155         int x = table->nr_entries;
156 
157         if (x >= ARRAY_SIZE(table->entries)) {
158                 pr_err("e820: too many entries; ignoring [mem %#010llx-%#010llx]\n", start, start + size - 1);
159                 return;
160         }
161 
162         table->entries[x].addr = start;
163         table->entries[x].size = size;
164         table->entries[x].type = type;
165         table->nr_entries++;
166 }
167 
168 void __init e820__range_add(u64 start, u64 size, enum e820_type type)
169 {
170         __e820__range_add(e820_table, start, size, type);
171 }
172 
173 static void __init e820_print_type(enum e820_type type)
174 {
175         switch (type) {
176         case E820_TYPE_RAM:             /* Fall through: */
177         case E820_TYPE_RESERVED_KERN:   pr_cont("usable");                      break;
178         case E820_TYPE_RESERVED:        pr_cont("reserved");                    break;
179         case E820_TYPE_ACPI:            pr_cont("ACPI data");                   break;
180         case E820_TYPE_NVS:             pr_cont("ACPI NVS");                    break;
181         case E820_TYPE_UNUSABLE:        pr_cont("unusable");                    break;
182         case E820_TYPE_PMEM:            /* Fall through: */
183         case E820_TYPE_PRAM:            pr_cont("persistent (type %u)", type);  break;
184         default:                        pr_cont("type %u", type);               break;
185         }
186 }
187 
188 void __init e820__print_table(char *who)
189 {
190         int i;
191 
192         for (i = 0; i < e820_table->nr_entries; i++) {
193                 pr_info("%s: [mem %#018Lx-%#018Lx] ", who,
194                        e820_table->entries[i].addr,
195                        e820_table->entries[i].addr + e820_table->entries[i].size - 1);
196 
197                 e820_print_type(e820_table->entries[i].type);
198                 pr_cont("\n");
199         }
200 }
201 
202 /*
203  * Sanitize an E820 map.
204  *
205  * Some E820 layouts include overlapping entries. The following
206  * replaces the original E820 map with a new one, removing overlaps,
207  * and resolving conflicting memory types in favor of highest
208  * numbered type.
209  *
210  * The input parameter 'entries' points to an array of 'struct
211  * e820_entry' which on entry has elements in the range [0, *nr_entries)
212  * valid, and which has space for up to max_nr_entries entries.
213  * On return, the resulting sanitized E820 map entries will be in
214  * overwritten in the same location, starting at 'entries'.
215  *
216  * The integer pointed to by nr_entries must be valid on entry (the
217  * current number of valid entries located at 'entries'). If the
218  * sanitizing succeeds the *nr_entries will be updated with the new
219  * number of valid entries (something no more than max_nr_entries).
220  *
221  * The return value from e820__update_table() is zero if it
222  * successfully 'sanitized' the map entries passed in, and is -1
223  * if it did nothing, which can happen if either of (1) it was
224  * only passed one map entry, or (2) any of the input map entries
225  * were invalid (start + size < start, meaning that the size was
226  * so big the described memory range wrapped around through zero.)
227  *
228  *      Visually we're performing the following
229  *      (1,2,3,4 = memory types)...
230  *
231  *      Sample memory map (w/overlaps):
232  *         ____22__________________
233  *         ______________________4_
234  *         ____1111________________
235  *         _44_____________________
236  *         11111111________________
237  *         ____________________33__
238  *         ___________44___________
239  *         __________33333_________
240  *         ______________22________
241  *         ___________________2222_
242  *         _________111111111______
243  *         _____________________11_
244  *         _________________4______
245  *
246  *      Sanitized equivalent (no overlap):
247  *         1_______________________
248  *         _44_____________________
249  *         ___1____________________
250  *         ____22__________________
251  *         ______11________________
252  *         _________1______________
253  *         __________3_____________
254  *         ___________44___________
255  *         _____________33_________
256  *         _______________2________
257  *         ________________1_______
258  *         _________________4______
259  *         ___________________2____
260  *         ____________________33__
261  *         ______________________4_
262  */
263 struct change_member {
264         /* Pointer to the original entry: */
265         struct e820_entry       *entry;
266         /* Address for this change point: */
267         unsigned long long      addr;
268 };
269 
270 static struct change_member     change_point_list[2*E820_MAX_ENTRIES]   __initdata;
271 static struct change_member     *change_point[2*E820_MAX_ENTRIES]       __initdata;
272 static struct e820_entry        *overlap_list[E820_MAX_ENTRIES]         __initdata;
273 static struct e820_entry        new_entries[E820_MAX_ENTRIES]           __initdata;
274 
275 static int __init cpcompare(const void *a, const void *b)
276 {
277         struct change_member * const *app = a, * const *bpp = b;
278         const struct change_member *ap = *app, *bp = *bpp;
279 
280         /*
281          * Inputs are pointers to two elements of change_point[].  If their
282          * addresses are not equal, their difference dominates.  If the addresses
283          * are equal, then consider one that represents the end of its region
284          * to be greater than one that does not.
285          */
286         if (ap->addr != bp->addr)
287                 return ap->addr > bp->addr ? 1 : -1;
288 
289         return (ap->addr != ap->entry->addr) - (bp->addr != bp->entry->addr);
290 }
291 
292 int __init e820__update_table(struct e820_table *table)
293 {
294         struct e820_entry *entries = table->entries;
295         u32 max_nr_entries = ARRAY_SIZE(table->entries);
296         enum e820_type current_type, last_type;
297         unsigned long long last_addr;
298         u32 new_nr_entries, overlap_entries;
299         u32 i, chg_idx, chg_nr;
300 
301         /* If there's only one memory region, don't bother: */
302         if (table->nr_entries < 2)
303                 return -1;
304 
305         BUG_ON(table->nr_entries > max_nr_entries);
306 
307         /* Bail out if we find any unreasonable addresses in the map: */
308         for (i = 0; i < table->nr_entries; i++) {
309                 if (entries[i].addr + entries[i].size < entries[i].addr)
310                         return -1;
311         }
312 
313         /* Create pointers for initial change-point information (for sorting): */
314         for (i = 0; i < 2 * table->nr_entries; i++)
315                 change_point[i] = &change_point_list[i];
316 
317         /*
318          * Record all known change-points (starting and ending addresses),
319          * omitting empty memory regions:
320          */
321         chg_idx = 0;
322         for (i = 0; i < table->nr_entries; i++) {
323                 if (entries[i].size != 0) {
324                         change_point[chg_idx]->addr     = entries[i].addr;
325                         change_point[chg_idx++]->entry  = &entries[i];
326                         change_point[chg_idx]->addr     = entries[i].addr + entries[i].size;
327                         change_point[chg_idx++]->entry  = &entries[i];
328                 }
329         }
330         chg_nr = chg_idx;
331 
332         /* Sort change-point list by memory addresses (low -> high): */
333         sort(change_point, chg_nr, sizeof(*change_point), cpcompare, NULL);
334 
335         /* Create a new memory map, removing overlaps: */
336         overlap_entries = 0;     /* Number of entries in the overlap table */
337         new_nr_entries = 0;      /* Index for creating new map entries */
338         last_type = 0;           /* Start with undefined memory type */
339         last_addr = 0;           /* Start with 0 as last starting address */
340 
341         /* Loop through change-points, determining effect on the new map: */
342         for (chg_idx = 0; chg_idx < chg_nr; chg_idx++) {
343                 /* Keep track of all overlapping entries */
344                 if (change_point[chg_idx]->addr == change_point[chg_idx]->entry->addr) {
345                         /* Add map entry to overlap list (> 1 entry implies an overlap) */
346                         overlap_list[overlap_entries++] = change_point[chg_idx]->entry;
347                 } else {
348                         /* Remove entry from list (order independent, so swap with last): */
349                         for (i = 0; i < overlap_entries; i++) {
350                                 if (overlap_list[i] == change_point[chg_idx]->entry)
351                                         overlap_list[i] = overlap_list[overlap_entries-1];
352                         }
353                         overlap_entries--;
354                 }
355                 /*
356                  * If there are overlapping entries, decide which
357                  * "type" to use (larger value takes precedence --
358                  * 1=usable, 2,3,4,4+=unusable)
359                  */
360                 current_type = 0;
361                 for (i = 0; i < overlap_entries; i++) {
362                         if (overlap_list[i]->type > current_type)
363                                 current_type = overlap_list[i]->type;
364                 }
365 
366                 /* Continue building up new map based on this information: */
367                 if (current_type != last_type || current_type == E820_TYPE_PRAM) {
368                         if (last_type != 0)      {
369                                 new_entries[new_nr_entries].size = change_point[chg_idx]->addr - last_addr;
370                                 /* Move forward only if the new size was non-zero: */
371                                 if (new_entries[new_nr_entries].size != 0)
372                                         /* No more space left for new entries? */
373                                         if (++new_nr_entries >= max_nr_entries)
374                                                 break;
375                         }
376                         if (current_type != 0)  {
377                                 new_entries[new_nr_entries].addr = change_point[chg_idx]->addr;
378                                 new_entries[new_nr_entries].type = current_type;
379                                 last_addr = change_point[chg_idx]->addr;
380                         }
381                         last_type = current_type;
382                 }
383         }
384 
385         /* Copy the new entries into the original location: */
386         memcpy(entries, new_entries, new_nr_entries*sizeof(*entries));
387         table->nr_entries = new_nr_entries;
388 
389         return 0;
390 }
391 
392 static int __init __append_e820_table(struct boot_e820_entry *entries, u32 nr_entries)
393 {
394         struct boot_e820_entry *entry = entries;
395 
396         while (nr_entries) {
397                 u64 start = entry->addr;
398                 u64 size = entry->size;
399                 u64 end = start + size - 1;
400                 u32 type = entry->type;
401 
402                 /* Ignore the entry on 64-bit overflow: */
403                 if (start > end && likely(size))
404                         return -1;
405 
406                 e820__range_add(start, size, type);
407 
408                 entry++;
409                 nr_entries--;
410         }
411         return 0;
412 }
413 
414 /*
415  * Copy the BIOS E820 map into a safe place.
416  *
417  * Sanity-check it while we're at it..
418  *
419  * If we're lucky and live on a modern system, the setup code
420  * will have given us a memory map that we can use to properly
421  * set up memory.  If we aren't, we'll fake a memory map.
422  */
423 static int __init append_e820_table(struct boot_e820_entry *entries, u32 nr_entries)
424 {
425         /* Only one memory region (or negative)? Ignore it */
426         if (nr_entries < 2)
427                 return -1;
428 
429         return __append_e820_table(entries, nr_entries);
430 }
431 
432 static u64 __init
433 __e820__range_update(struct e820_table *table, u64 start, u64 size, enum e820_type old_type, enum e820_type new_type)
434 {
435         u64 end;
436         unsigned int i;
437         u64 real_updated_size = 0;
438 
439         BUG_ON(old_type == new_type);
440 
441         if (size > (ULLONG_MAX - start))
442                 size = ULLONG_MAX - start;
443 
444         end = start + size;
445         printk(KERN_DEBUG "e820: update [mem %#010Lx-%#010Lx] ", start, end - 1);
446         e820_print_type(old_type);
447         pr_cont(" ==> ");
448         e820_print_type(new_type);
449         pr_cont("\n");
450 
451         for (i = 0; i < table->nr_entries; i++) {
452                 struct e820_entry *entry = &table->entries[i];
453                 u64 final_start, final_end;
454                 u64 entry_end;
455 
456                 if (entry->type != old_type)
457                         continue;
458 
459                 entry_end = entry->addr + entry->size;
460 
461                 /* Completely covered by new range? */
462                 if (entry->addr >= start && entry_end <= end) {
463                         entry->type = new_type;
464                         real_updated_size += entry->size;
465                         continue;
466                 }
467 
468                 /* New range is completely covered? */
469                 if (entry->addr < start && entry_end > end) {
470                         __e820__range_add(table, start, size, new_type);
471                         __e820__range_add(table, end, entry_end - end, entry->type);
472                         entry->size = start - entry->addr;
473                         real_updated_size += size;
474                         continue;
475                 }
476 
477                 /* Partially covered: */
478                 final_start = max(start, entry->addr);
479                 final_end = min(end, entry_end);
480                 if (final_start >= final_end)
481                         continue;
482 
483                 __e820__range_add(table, final_start, final_end - final_start, new_type);
484 
485                 real_updated_size += final_end - final_start;
486 
487                 /*
488                  * Left range could be head or tail, so need to update
489                  * its size first:
490                  */
491                 entry->size -= final_end - final_start;
492                 if (entry->addr < final_start)
493                         continue;
494 
495                 entry->addr = final_end;
496         }
497         return real_updated_size;
498 }
499 
500 u64 __init e820__range_update(u64 start, u64 size, enum e820_type old_type, enum e820_type new_type)
501 {
502         return __e820__range_update(e820_table, start, size, old_type, new_type);
503 }
504 
505 static u64 __init e820__range_update_kexec(u64 start, u64 size, enum e820_type old_type, enum e820_type  new_type)
506 {
507         return __e820__range_update(e820_table_kexec, start, size, old_type, new_type);
508 }
509 
510 /* Remove a range of memory from the E820 table: */
511 u64 __init e820__range_remove(u64 start, u64 size, enum e820_type old_type, bool check_type)
512 {
513         int i;
514         u64 end;
515         u64 real_removed_size = 0;
516 
517         if (size > (ULLONG_MAX - start))
518                 size = ULLONG_MAX - start;
519 
520         end = start + size;
521         printk(KERN_DEBUG "e820: remove [mem %#010Lx-%#010Lx] ", start, end - 1);
522         if (check_type)
523                 e820_print_type(old_type);
524         pr_cont("\n");
525 
526         for (i = 0; i < e820_table->nr_entries; i++) {
527                 struct e820_entry *entry = &e820_table->entries[i];
528                 u64 final_start, final_end;
529                 u64 entry_end;
530 
531                 if (check_type && entry->type != old_type)
532                         continue;
533 
534                 entry_end = entry->addr + entry->size;
535 
536                 /* Completely covered? */
537                 if (entry->addr >= start && entry_end <= end) {
538                         real_removed_size += entry->size;
539                         memset(entry, 0, sizeof(*entry));
540                         continue;
541                 }
542 
543                 /* Is the new range completely covered? */
544                 if (entry->addr < start && entry_end > end) {
545                         e820__range_add(end, entry_end - end, entry->type);
546                         entry->size = start - entry->addr;
547                         real_removed_size += size;
548                         continue;
549                 }
550 
551                 /* Partially covered: */
552                 final_start = max(start, entry->addr);
553                 final_end = min(end, entry_end);
554                 if (final_start >= final_end)
555                         continue;
556 
557                 real_removed_size += final_end - final_start;
558 
559                 /*
560                  * Left range could be head or tail, so need to update
561                  * the size first:
562                  */
563                 entry->size -= final_end - final_start;
564                 if (entry->addr < final_start)
565                         continue;
566 
567                 entry->addr = final_end;
568         }
569         return real_removed_size;
570 }
571 
572 void __init e820__update_table_print(void)
573 {
574         if (e820__update_table(e820_table))
575                 return;
576 
577         pr_info("e820: modified physical RAM map:\n");
578         e820__print_table("modified");
579 }
580 
581 static void __init e820__update_table_kexec(void)
582 {
583         e820__update_table(e820_table_kexec);
584 }
585 
586 #define MAX_GAP_END 0x100000000ull
587 
588 /*
589  * Search for a gap in the E820 memory space from 0 to MAX_GAP_END (4GB).
590  */
591 static int __init e820_search_gap(unsigned long *gapstart, unsigned long *gapsize)
592 {
593         unsigned long long last = MAX_GAP_END;
594         int i = e820_table->nr_entries;
595         int found = 0;
596 
597         while (--i >= 0) {
598                 unsigned long long start = e820_table->entries[i].addr;
599                 unsigned long long end = start + e820_table->entries[i].size;
600 
601                 /*
602                  * Since "last" is at most 4GB, we know we'll
603                  * fit in 32 bits if this condition is true:
604                  */
605                 if (last > end) {
606                         unsigned long gap = last - end;
607 
608                         if (gap >= *gapsize) {
609                                 *gapsize = gap;
610                                 *gapstart = end;
611                                 found = 1;
612                         }
613                 }
614                 if (start < last)
615                         last = start;
616         }
617         return found;
618 }
619 
620 /*
621  * Search for the biggest gap in the low 32 bits of the E820
622  * memory space. We pass this space to the PCI subsystem, so
623  * that it can assign MMIO resources for hotplug or
624  * unconfigured devices in.
625  *
626  * Hopefully the BIOS let enough space left.
627  */
628 __init void e820__setup_pci_gap(void)
629 {
630         unsigned long gapstart, gapsize;
631         int found;
632 
633         gapsize = 0x400000;
634         found  = e820_search_gap(&gapstart, &gapsize);
635 
636         if (!found) {
637 #ifdef CONFIG_X86_64
638                 gapstart = (max_pfn << PAGE_SHIFT) + 1024*1024;
639                 pr_err(
640                         "e820: Cannot find an available gap in the 32-bit address range\n"
641                         "e820: PCI devices with unassigned 32-bit BARs may not work!\n");
642 #else
643                 gapstart = 0x10000000;
644 #endif
645         }
646 
647         /*
648          * e820__reserve_resources_late() protects stolen RAM already:
649          */
650         pci_mem_start = gapstart;
651 
652         pr_info("e820: [mem %#010lx-%#010lx] available for PCI devices\n", gapstart, gapstart + gapsize - 1);
653 }
654 
655 /*
656  * Called late during init, in free_initmem().
657  *
658  * Initial e820_table and e820_table_kexec are largish __initdata arrays.
659  *
660  * Copy them to a (usually much smaller) dynamically allocated area that is
661  * sized precisely after the number of e820 entries.
662  *
663  * This is done after we've performed all the fixes and tweaks to the tables.
664  * All functions which modify them are __init functions, which won't exist
665  * after free_initmem().
666  */
667 __init void e820__reallocate_tables(void)
668 {
669         struct e820_table *n;
670         int size;
671 
672         size = offsetof(struct e820_table, entries) + sizeof(struct e820_entry)*e820_table->nr_entries;
673         n = kmalloc(size, GFP_KERNEL);
674         BUG_ON(!n);
675         memcpy(n, e820_table, size);
676         e820_table = n;
677 
678         size = offsetof(struct e820_table, entries) + sizeof(struct e820_entry)*e820_table_kexec->nr_entries;
679         n = kmalloc(size, GFP_KERNEL);
680         BUG_ON(!n);
681         memcpy(n, e820_table_kexec, size);
682         e820_table_kexec = n;
683 
684         size = offsetof(struct e820_table, entries) + sizeof(struct e820_entry)*e820_table_firmware->nr_entries;
685         n = kmalloc(size, GFP_KERNEL);
686         BUG_ON(!n);
687         memcpy(n, e820_table_firmware, size);
688         e820_table_firmware = n;
689 }
690 
691 /*
692  * Because of the small fixed size of struct boot_params, only the first
693  * 128 E820 memory entries are passed to the kernel via boot_params.e820_table,
694  * the remaining (if any) entries are passed via the SETUP_E820_EXT node of
695  * struct setup_data, which is parsed here.
696  */
697 void __init e820__memory_setup_extended(u64 phys_addr, u32 data_len)
698 {
699         int entries;
700         struct boot_e820_entry *extmap;
701         struct setup_data *sdata;
702 
703         sdata = early_memremap(phys_addr, data_len);
704         entries = sdata->len / sizeof(*extmap);
705         extmap = (struct boot_e820_entry *)(sdata->data);
706 
707         __append_e820_table(extmap, entries);
708         e820__update_table(e820_table);
709 
710         memcpy(e820_table_kexec, e820_table, sizeof(*e820_table_kexec));
711         memcpy(e820_table_firmware, e820_table, sizeof(*e820_table_firmware));
712 
713         early_memunmap(sdata, data_len);
714         pr_info("e820: extended physical RAM map:\n");
715         e820__print_table("extended");
716 }
717 
718 /*
719  * Find the ranges of physical addresses that do not correspond to
720  * E820 RAM areas and register the corresponding pages as 'nosave' for
721  * hibernation (32-bit) or software suspend and suspend to RAM (64-bit).
722  *
723  * This function requires the E820 map to be sorted and without any
724  * overlapping entries.
725  */
726 void __init e820__register_nosave_regions(unsigned long limit_pfn)
727 {
728         int i;
729         unsigned long pfn = 0;
730 
731         for (i = 0; i < e820_table->nr_entries; i++) {
732                 struct e820_entry *entry = &e820_table->entries[i];
733 
734                 if (pfn < PFN_UP(entry->addr))
735                         register_nosave_region(pfn, PFN_UP(entry->addr));
736 
737                 pfn = PFN_DOWN(entry->addr + entry->size);
738 
739                 if (entry->type != E820_TYPE_RAM && entry->type != E820_TYPE_RESERVED_KERN)
740                         register_nosave_region(PFN_UP(entry->addr), pfn);
741 
742                 if (pfn >= limit_pfn)
743                         break;
744         }
745 }
746 
747 #ifdef CONFIG_ACPI
748 /*
749  * Register ACPI NVS memory regions, so that we can save/restore them during
750  * hibernation and the subsequent resume:
751  */
752 static int __init e820__register_nvs_regions(void)
753 {
754         int i;
755 
756         for (i = 0; i < e820_table->nr_entries; i++) {
757                 struct e820_entry *entry = &e820_table->entries[i];
758 
759                 if (entry->type == E820_TYPE_NVS)
760                         acpi_nvs_register(entry->addr, entry->size);
761         }
762 
763         return 0;
764 }
765 core_initcall(e820__register_nvs_regions);
766 #endif
767 
768 /*
769  * Allocate the requested number of bytes with the requsted alignment
770  * and return (the physical address) to the caller. Also register this
771  * range in the 'kexec' E820 table as a reserved range.
772  *
773  * This allows kexec to fake a new mptable, as if it came from the real
774  * system.
775  */
776 u64 __init e820__memblock_alloc_reserved(u64 size, u64 align)
777 {
778         u64 addr;
779 
780         addr = __memblock_alloc_base(size, align, MEMBLOCK_ALLOC_ACCESSIBLE);
781         if (addr) {
782                 e820__range_update_kexec(addr, size, E820_TYPE_RAM, E820_TYPE_RESERVED);
783                 pr_info("e820: update e820_table_kexec for e820__memblock_alloc_reserved()\n");
784                 e820__update_table_kexec();
785         }
786 
787         return addr;
788 }
789 
790 #ifdef CONFIG_X86_32
791 # ifdef CONFIG_X86_PAE
792 #  define MAX_ARCH_PFN          (1ULL<<(36-PAGE_SHIFT))
793 # else
794 #  define MAX_ARCH_PFN          (1ULL<<(32-PAGE_SHIFT))
795 # endif
796 #else /* CONFIG_X86_32 */
797 # define MAX_ARCH_PFN MAXMEM>>PAGE_SHIFT
798 #endif
799 
800 /*
801  * Find the highest page frame number we have available
802  */
803 static unsigned long __init e820_end_pfn(unsigned long limit_pfn, enum e820_type type)
804 {
805         int i;
806         unsigned long last_pfn = 0;
807         unsigned long max_arch_pfn = MAX_ARCH_PFN;
808 
809         for (i = 0; i < e820_table->nr_entries; i++) {
810                 struct e820_entry *entry = &e820_table->entries[i];
811                 unsigned long start_pfn;
812                 unsigned long end_pfn;
813 
814                 if (entry->type != type)
815                         continue;
816 
817                 start_pfn = entry->addr >> PAGE_SHIFT;
818                 end_pfn = (entry->addr + entry->size) >> PAGE_SHIFT;
819 
820                 if (start_pfn >= limit_pfn)
821                         continue;
822                 if (end_pfn > limit_pfn) {
823                         last_pfn = limit_pfn;
824                         break;
825                 }
826                 if (end_pfn > last_pfn)
827                         last_pfn = end_pfn;
828         }
829 
830         if (last_pfn > max_arch_pfn)
831                 last_pfn = max_arch_pfn;
832 
833         pr_info("e820: last_pfn = %#lx max_arch_pfn = %#lx\n",
834                          last_pfn, max_arch_pfn);
835         return last_pfn;
836 }
837 
838 unsigned long __init e820__end_of_ram_pfn(void)
839 {
840         return e820_end_pfn(MAX_ARCH_PFN, E820_TYPE_RAM);
841 }
842 
843 unsigned long __init e820__end_of_low_ram_pfn(void)
844 {
845         return e820_end_pfn(1UL << (32 - PAGE_SHIFT), E820_TYPE_RAM);
846 }
847 
848 static void __init early_panic(char *msg)
849 {
850         early_printk(msg);
851         panic(msg);
852 }
853 
854 static int userdef __initdata;
855 
856 /* The "mem=nopentium" boot option disables 4MB page tables on 32-bit kernels: */
857 static int __init parse_memopt(char *p)
858 {
859         u64 mem_size;
860 
861         if (!p)
862                 return -EINVAL;
863 
864         if (!strcmp(p, "nopentium")) {
865 #ifdef CONFIG_X86_32
866                 setup_clear_cpu_cap(X86_FEATURE_PSE);
867                 return 0;
868 #else
869                 pr_warn("mem=nopentium ignored! (only supported on x86_32)\n");
870                 return -EINVAL;
871 #endif
872         }
873 
874         userdef = 1;
875         mem_size = memparse(p, &p);
876 
877         /* Don't remove all memory when getting "mem={invalid}" parameter: */
878         if (mem_size == 0)
879                 return -EINVAL;
880 
881         e820__range_remove(mem_size, ULLONG_MAX - mem_size, E820_TYPE_RAM, 1);
882 
883         return 0;
884 }
885 early_param("mem", parse_memopt);
886 
887 static int __init parse_memmap_one(char *p)
888 {
889         char *oldp;
890         u64 start_at, mem_size;
891 
892         if (!p)
893                 return -EINVAL;
894 
895         if (!strncmp(p, "exactmap", 8)) {
896 #ifdef CONFIG_CRASH_DUMP
897                 /*
898                  * If we are doing a crash dump, we still need to know
899                  * the real memory size before the original memory map is
900                  * reset.
901                  */
902                 saved_max_pfn = e820__end_of_ram_pfn();
903 #endif
904                 e820_table->nr_entries = 0;
905                 userdef = 1;
906                 return 0;
907         }
908 
909         oldp = p;
910         mem_size = memparse(p, &p);
911         if (p == oldp)
912                 return -EINVAL;
913 
914         userdef = 1;
915         if (*p == '@') {
916                 start_at = memparse(p+1, &p);
917                 e820__range_add(start_at, mem_size, E820_TYPE_RAM);
918         } else if (*p == '#') {
919                 start_at = memparse(p+1, &p);
920                 e820__range_add(start_at, mem_size, E820_TYPE_ACPI);
921         } else if (*p == '$') {
922                 start_at = memparse(p+1, &p);
923                 e820__range_add(start_at, mem_size, E820_TYPE_RESERVED);
924         } else if (*p == '!') {
925                 start_at = memparse(p+1, &p);
926                 e820__range_add(start_at, mem_size, E820_TYPE_PRAM);
927         } else {
928                 e820__range_remove(mem_size, ULLONG_MAX - mem_size, E820_TYPE_RAM, 1);
929         }
930 
931         return *p == '\0' ? 0 : -EINVAL;
932 }
933 
934 static int __init parse_memmap_opt(char *str)
935 {
936         while (str) {
937                 char *k = strchr(str, ',');
938 
939                 if (k)
940                         *k++ = 0;
941 
942                 parse_memmap_one(str);
943                 str = k;
944         }
945 
946         return 0;
947 }
948 early_param("memmap", parse_memmap_opt);
949 
950 /*
951  * Reserve all entries from the bootloader's extensible data nodes list,
952  * because if present we are going to use it later on to fetch e820
953  * entries from it:
954  */
955 void __init e820__reserve_setup_data(void)
956 {
957         struct setup_data *data;
958         u64 pa_data;
959 
960         pa_data = boot_params.hdr.setup_data;
961         if (!pa_data)
962                 return;
963 
964         while (pa_data) {
965                 data = early_memremap(pa_data, sizeof(*data));
966                 e820__range_update(pa_data, sizeof(*data)+data->len, E820_TYPE_RAM, E820_TYPE_RESERVED_KERN);
967                 e820__range_update_kexec(pa_data, sizeof(*data)+data->len, E820_TYPE_RAM, E820_TYPE_RESERVED_KERN);
968                 pa_data = data->next;
969                 early_memunmap(data, sizeof(*data));
970         }
971 
972         e820__update_table(e820_table);
973         e820__update_table(e820_table_kexec);
974 
975         pr_info("extended physical RAM map:\n");
976         e820__print_table("reserve setup_data");
977 }
978 
979 /*
980  * Called after parse_early_param(), after early parameters (such as mem=)
981  * have been processed, in which case we already have an E820 table filled in
982  * via the parameter callback function(s), but it's not sorted and printed yet:
983  */
984 void __init e820__finish_early_params(void)
985 {
986         if (userdef) {
987                 if (e820__update_table(e820_table) < 0)
988                         early_panic("Invalid user supplied memory map");
989 
990                 pr_info("e820: user-defined physical RAM map:\n");
991                 e820__print_table("user");
992         }
993 }
994 
995 static const char *__init e820_type_to_string(struct e820_entry *entry)
996 {
997         switch (entry->type) {
998         case E820_TYPE_RESERVED_KERN:   /* Fall-through: */
999         case E820_TYPE_RAM:             return "System RAM";
1000         case E820_TYPE_ACPI:            return "ACPI Tables";
1001         case E820_TYPE_NVS:             return "ACPI Non-volatile Storage";
1002         case E820_TYPE_UNUSABLE:        return "Unusable memory";
1003         case E820_TYPE_PRAM:            return "Persistent Memory (legacy)";
1004         case E820_TYPE_PMEM:            return "Persistent Memory";
1005         case E820_TYPE_RESERVED:        return "Reserved";
1006         default:                        return "Unknown E820 type";
1007         }
1008 }
1009 
1010 static unsigned long __init e820_type_to_iomem_type(struct e820_entry *entry)
1011 {
1012         switch (entry->type) {
1013         case E820_TYPE_RESERVED_KERN:   /* Fall-through: */
1014         case E820_TYPE_RAM:             return IORESOURCE_SYSTEM_RAM;
1015         case E820_TYPE_ACPI:            /* Fall-through: */
1016         case E820_TYPE_NVS:             /* Fall-through: */
1017         case E820_TYPE_UNUSABLE:        /* Fall-through: */
1018         case E820_TYPE_PRAM:            /* Fall-through: */
1019         case E820_TYPE_PMEM:            /* Fall-through: */
1020         case E820_TYPE_RESERVED:        /* Fall-through: */
1021         default:                        return IORESOURCE_MEM;
1022         }
1023 }
1024 
1025 static unsigned long __init e820_type_to_iores_desc(struct e820_entry *entry)
1026 {
1027         switch (entry->type) {
1028         case E820_TYPE_ACPI:            return IORES_DESC_ACPI_TABLES;
1029         case E820_TYPE_NVS:             return IORES_DESC_ACPI_NV_STORAGE;
1030         case E820_TYPE_PMEM:            return IORES_DESC_PERSISTENT_MEMORY;
1031         case E820_TYPE_PRAM:            return IORES_DESC_PERSISTENT_MEMORY_LEGACY;
1032         case E820_TYPE_RESERVED_KERN:   /* Fall-through: */
1033         case E820_TYPE_RAM:             /* Fall-through: */
1034         case E820_TYPE_UNUSABLE:        /* Fall-through: */
1035         case E820_TYPE_RESERVED:        /* Fall-through: */
1036         default:                        return IORES_DESC_NONE;
1037         }
1038 }
1039 
1040 static bool __init do_mark_busy(enum e820_type type, struct resource *res)
1041 {
1042         /* this is the legacy bios/dos rom-shadow + mmio region */
1043         if (res->start < (1ULL<<20))
1044                 return true;
1045 
1046         /*
1047          * Treat persistent memory like device memory, i.e. reserve it
1048          * for exclusive use of a driver
1049          */
1050         switch (type) {
1051         case E820_TYPE_RESERVED:
1052         case E820_TYPE_PRAM:
1053         case E820_TYPE_PMEM:
1054                 return false;
1055         case E820_TYPE_RESERVED_KERN:
1056         case E820_TYPE_RAM:
1057         case E820_TYPE_ACPI:
1058         case E820_TYPE_NVS:
1059         case E820_TYPE_UNUSABLE:
1060         default:
1061                 return true;
1062         }
1063 }
1064 
1065 /*
1066  * Mark E820 reserved areas as busy for the resource manager:
1067  */
1068 
1069 static struct resource __initdata *e820_res;
1070 
1071 void __init e820__reserve_resources(void)
1072 {
1073         int i;
1074         struct resource *res;
1075         u64 end;
1076 
1077         res = alloc_bootmem(sizeof(*res) * e820_table->nr_entries);
1078         e820_res = res;
1079 
1080         for (i = 0; i < e820_table->nr_entries; i++) {
1081                 struct e820_entry *entry = e820_table->entries + i;
1082 
1083                 end = entry->addr + entry->size - 1;
1084                 if (end != (resource_size_t)end) {
1085                         res++;
1086                         continue;
1087                 }
1088                 res->start = entry->addr;
1089                 res->end   = end;
1090                 res->name  = e820_type_to_string(entry);
1091                 res->flags = e820_type_to_iomem_type(entry);
1092                 res->desc  = e820_type_to_iores_desc(entry);
1093 
1094                 /*
1095                  * Don't register the region that could be conflicted with
1096                  * PCI device BAR resources and insert them later in
1097                  * pcibios_resource_survey():
1098                  */
1099                 if (do_mark_busy(entry->type, res)) {
1100                         res->flags |= IORESOURCE_BUSY;
1101                         insert_resource(&iomem_resource, res);
1102                 }
1103                 res++;
1104         }
1105 
1106         /* Expose the bootloader-provided memory layout to the sysfs. */
1107         for (i = 0; i < e820_table_firmware->nr_entries; i++) {
1108                 struct e820_entry *entry = e820_table_firmware->entries + i;
1109 
1110                 firmware_map_add_early(entry->addr, entry->addr + entry->size, e820_type_to_string(entry));
1111         }
1112 }
1113 
1114 /*
1115  * How much should we pad the end of RAM, depending on where it is?
1116  */
1117 static unsigned long __init ram_alignment(resource_size_t pos)
1118 {
1119         unsigned long mb = pos >> 20;
1120 
1121         /* To 64kB in the first megabyte */
1122         if (!mb)
1123                 return 64*1024;
1124 
1125         /* To 1MB in the first 16MB */
1126         if (mb < 16)
1127                 return 1024*1024;
1128 
1129         /* To 64MB for anything above that */
1130         return 64*1024*1024;
1131 }
1132 
1133 #define MAX_RESOURCE_SIZE ((resource_size_t)-1)
1134 
1135 void __init e820__reserve_resources_late(void)
1136 {
1137         int i;
1138         struct resource *res;
1139 
1140         res = e820_res;
1141         for (i = 0; i < e820_table->nr_entries; i++) {
1142                 if (!res->parent && res->end)
1143                         insert_resource_expand_to_fit(&iomem_resource, res);
1144                 res++;
1145         }
1146 
1147         /*
1148          * Try to bump up RAM regions to reasonable boundaries, to
1149          * avoid stolen RAM:
1150          */
1151         for (i = 0; i < e820_table->nr_entries; i++) {
1152                 struct e820_entry *entry = &e820_table->entries[i];
1153                 u64 start, end;
1154 
1155                 if (entry->type != E820_TYPE_RAM)
1156                         continue;
1157 
1158                 start = entry->addr + entry->size;
1159                 end = round_up(start, ram_alignment(start)) - 1;
1160                 if (end > MAX_RESOURCE_SIZE)
1161                         end = MAX_RESOURCE_SIZE;
1162                 if (start >= end)
1163                         continue;
1164 
1165                 printk(KERN_DEBUG "e820: reserve RAM buffer [mem %#010llx-%#010llx]\n", start, end);
1166                 reserve_region_with_split(&iomem_resource, start, end, "RAM buffer");
1167         }
1168 }
1169 
1170 /*
1171  * Pass the firmware (bootloader) E820 map to the kernel and process it:
1172  */
1173 char *__init e820__memory_setup_default(void)
1174 {
1175         char *who = "BIOS-e820";
1176 
1177         /*
1178          * Try to copy the BIOS-supplied E820-map.
1179          *
1180          * Otherwise fake a memory map; one section from 0k->640k,
1181          * the next section from 1mb->appropriate_mem_k
1182          */
1183         if (append_e820_table(boot_params.e820_table, boot_params.e820_entries) < 0) {
1184                 u64 mem_size;
1185 
1186                 /* Compare results from other methods and take the one that gives more RAM: */
1187                 if (boot_params.alt_mem_k < boot_params.screen_info.ext_mem_k) {
1188                         mem_size = boot_params.screen_info.ext_mem_k;
1189                         who = "BIOS-88";
1190                 } else {
1191                         mem_size = boot_params.alt_mem_k;
1192                         who = "BIOS-e801";
1193                 }
1194 
1195                 e820_table->nr_entries = 0;
1196                 e820__range_add(0, LOWMEMSIZE(), E820_TYPE_RAM);
1197                 e820__range_add(HIGH_MEMORY, mem_size << 10, E820_TYPE_RAM);
1198         }
1199 
1200         /* We just appended a lot of ranges, sanitize the table: */
1201         e820__update_table(e820_table);
1202 
1203         return who;
1204 }
1205 
1206 /*
1207  * Calls e820__memory_setup_default() in essence to pick up the firmware/bootloader
1208  * E820 map - with an optional platform quirk available for virtual platforms
1209  * to override this method of boot environment processing:
1210  */
1211 void __init e820__memory_setup(void)
1212 {
1213         char *who;
1214 
1215         /* This is a firmware interface ABI - make sure we don't break it: */
1216         BUILD_BUG_ON(sizeof(struct boot_e820_entry) != 20);
1217 
1218         who = x86_init.resources.memory_setup();
1219 
1220         memcpy(e820_table_kexec, e820_table, sizeof(*e820_table_kexec));
1221         memcpy(e820_table_firmware, e820_table, sizeof(*e820_table_firmware));
1222 
1223         pr_info("e820: BIOS-provided physical RAM map:\n");
1224         e820__print_table(who);
1225 }
1226 
1227 void __init e820__memblock_setup(void)
1228 {
1229         int i;
1230         u64 end;
1231 
1232         /*
1233          * The bootstrap memblock region count maximum is 128 entries
1234          * (INIT_MEMBLOCK_REGIONS), but EFI might pass us more E820 entries
1235          * than that - so allow memblock resizing.
1236          *
1237          * This is safe, because this call happens pretty late during x86 setup,
1238          * so we know about reserved memory regions already. (This is important
1239          * so that memblock resizing does no stomp over reserved areas.)
1240          */
1241         memblock_allow_resize();
1242 
1243         for (i = 0; i < e820_table->nr_entries; i++) {
1244                 struct e820_entry *entry = &e820_table->entries[i];
1245 
1246                 end = entry->addr + entry->size;
1247                 if (end != (resource_size_t)end)
1248                         continue;
1249 
1250                 if (entry->type != E820_TYPE_RAM && entry->type != E820_TYPE_RESERVED_KERN)
1251                         continue;
1252 
1253                 memblock_add(entry->addr, entry->size);
1254         }
1255 
1256         /* Throw away partial pages: */
1257         memblock_trim_memory(PAGE_SIZE);
1258 
1259         memblock_dump_all();
1260 }
1261 

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