2 * Low level x86 E820 memory map handling functions.
4 * The firmware and bootloader passes us the "E820 table", which is the primary
5 * physical memory layout description available about x86 systems.
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.).
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>
19 #include <asm/e820/api.h>
20 #include <asm/setup.h>
23 * We organize the E820 table into three main data structures:
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:
30 * - inform the user about the firmware's notion of memory layout
31 * via /sys/firmware/memmap
33 * - the hibernation code uses it to generate a kernel-independent MD5
34 * fingerprint of the physical memory layout of a system.
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.
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.
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.
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.
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
;
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
;
66 /* For PCI or other memory-mapped resources */
67 unsigned long pci_mem_start
= 0xaeedbabe;
69 EXPORT_SYMBOL(pci_mem_start
);
73 * This function checks if any part of the range <start,end> is mapped
76 bool e820__mapped_any(u64 start
, u64 end
, enum e820_type type
)
80 for (i
= 0; i
< e820_table
->nr_entries
; i
++) {
81 struct e820_entry
*entry
= &e820_table
->entries
[i
];
83 if (type
&& entry
->type
!= type
)
85 if (entry
->addr
>= end
|| entry
->addr
+ entry
->size
<= start
)
91 EXPORT_SYMBOL_GPL(e820__mapped_any
);
94 * This function checks if the entire <start,end> range is mapped with 'type'.
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.
99 static struct e820_entry
*__e820__mapped_all(u64 start
, u64 end
,
104 for (i
= 0; i
< e820_table
->nr_entries
; i
++) {
105 struct e820_entry
*entry
= &e820_table
->entries
[i
];
107 if (type
&& entry
->type
!= type
)
110 /* Is the region (part) in overlap with the current region? */
111 if (entry
->addr
>= end
|| entry
->addr
+ entry
->size
<= start
)
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
118 if (entry
->addr
<= start
)
119 start
= entry
->addr
+ entry
->size
;
122 * If 'start' is now at or beyond 'end', we're done, full
123 * coverage of the desired range exists:
133 * This function checks if the entire range <start,end> is mapped with type.
135 bool __init
e820__mapped_all(u64 start
, u64 end
, enum e820_type type
)
137 return __e820__mapped_all(start
, end
, type
);
141 * This function returns the type associated with the range <start,end>.
143 int e820__get_entry_type(u64 start
, u64 end
)
145 struct e820_entry
*entry
= __e820__mapped_all(start
, end
, 0);
147 return entry
? entry
->type
: -EINVAL
;
151 * Add a memory region to the kernel E820 map.
153 static void __init
__e820__range_add(struct e820_table
*table
, u64 start
, u64 size
, enum e820_type type
)
155 int x
= table
->nr_entries
;
157 if (x
>= ARRAY_SIZE(table
->entries
)) {
158 pr_err("too many entries; ignoring [mem %#010llx-%#010llx]\n",
159 start
, start
+ size
- 1);
163 table
->entries
[x
].addr
= start
;
164 table
->entries
[x
].size
= size
;
165 table
->entries
[x
].type
= type
;
169 void __init
e820__range_add(u64 start
, u64 size
, enum e820_type type
)
171 __e820__range_add(e820_table
, start
, size
, type
);
174 static void __init
e820_print_type(enum e820_type type
)
177 case E820_TYPE_RAM
: /* Fall through: */
178 case E820_TYPE_RESERVED_KERN
: pr_cont("usable"); break;
179 case E820_TYPE_RESERVED
: pr_cont("reserved"); break;
180 case E820_TYPE_ACPI
: pr_cont("ACPI data"); break;
181 case E820_TYPE_NVS
: pr_cont("ACPI NVS"); break;
182 case E820_TYPE_UNUSABLE
: pr_cont("unusable"); break;
183 case E820_TYPE_PMEM
: /* Fall through: */
184 case E820_TYPE_PRAM
: pr_cont("persistent (type %u)", type
); break;
185 default: pr_cont("type %u", type
); break;
189 void __init
e820__print_table(char *who
)
193 for (i
= 0; i
< e820_table
->nr_entries
; i
++) {
194 pr_info("%s: [mem %#018Lx-%#018Lx] ",
196 e820_table
->entries
[i
].addr
,
197 e820_table
->entries
[i
].addr
+ e820_table
->entries
[i
].size
- 1);
199 e820_print_type(e820_table
->entries
[i
].type
);
205 * Sanitize an E820 map.
207 * Some E820 layouts include overlapping entries. The following
208 * replaces the original E820 map with a new one, removing overlaps,
209 * and resolving conflicting memory types in favor of highest
212 * The input parameter 'entries' points to an array of 'struct
213 * e820_entry' which on entry has elements in the range [0, *nr_entries)
214 * valid, and which has space for up to max_nr_entries entries.
215 * On return, the resulting sanitized E820 map entries will be in
216 * overwritten in the same location, starting at 'entries'.
218 * The integer pointed to by nr_entries must be valid on entry (the
219 * current number of valid entries located at 'entries'). If the
220 * sanitizing succeeds the *nr_entries will be updated with the new
221 * number of valid entries (something no more than max_nr_entries).
223 * The return value from e820__update_table() is zero if it
224 * successfully 'sanitized' the map entries passed in, and is -1
225 * if it did nothing, which can happen if either of (1) it was
226 * only passed one map entry, or (2) any of the input map entries
227 * were invalid (start + size < start, meaning that the size was
228 * so big the described memory range wrapped around through zero.)
230 * Visually we're performing the following
231 * (1,2,3,4 = memory types)...
233 * Sample memory map (w/overlaps):
234 * ____22__________________
235 * ______________________4_
236 * ____1111________________
237 * _44_____________________
238 * 11111111________________
239 * ____________________33__
240 * ___________44___________
241 * __________33333_________
242 * ______________22________
243 * ___________________2222_
244 * _________111111111______
245 * _____________________11_
246 * _________________4______
248 * Sanitized equivalent (no overlap):
249 * 1_______________________
250 * _44_____________________
251 * ___1____________________
252 * ____22__________________
253 * ______11________________
254 * _________1______________
255 * __________3_____________
256 * ___________44___________
257 * _____________33_________
258 * _______________2________
259 * ________________1_______
260 * _________________4______
261 * ___________________2____
262 * ____________________33__
263 * ______________________4_
265 struct change_member
{
266 /* Pointer to the original entry: */
267 struct e820_entry
*entry
;
268 /* Address for this change point: */
269 unsigned long long addr
;
272 static struct change_member change_point_list
[2*E820_MAX_ENTRIES
] __initdata
;
273 static struct change_member
*change_point
[2*E820_MAX_ENTRIES
] __initdata
;
274 static struct e820_entry
*overlap_list
[E820_MAX_ENTRIES
] __initdata
;
275 static struct e820_entry new_entries
[E820_MAX_ENTRIES
] __initdata
;
277 static int __init
cpcompare(const void *a
, const void *b
)
279 struct change_member
* const *app
= a
, * const *bpp
= b
;
280 const struct change_member
*ap
= *app
, *bp
= *bpp
;
283 * Inputs are pointers to two elements of change_point[]. If their
284 * addresses are not equal, their difference dominates. If the addresses
285 * are equal, then consider one that represents the end of its region
286 * to be greater than one that does not.
288 if (ap
->addr
!= bp
->addr
)
289 return ap
->addr
> bp
->addr
? 1 : -1;
291 return (ap
->addr
!= ap
->entry
->addr
) - (bp
->addr
!= bp
->entry
->addr
);
294 int __init
e820__update_table(struct e820_table
*table
)
296 struct e820_entry
*entries
= table
->entries
;
297 u32 max_nr_entries
= ARRAY_SIZE(table
->entries
);
298 enum e820_type current_type
, last_type
;
299 unsigned long long last_addr
;
300 u32 new_nr_entries
, overlap_entries
;
301 u32 i
, chg_idx
, chg_nr
;
303 /* If there's only one memory region, don't bother: */
304 if (table
->nr_entries
< 2)
307 BUG_ON(table
->nr_entries
> max_nr_entries
);
309 /* Bail out if we find any unreasonable addresses in the map: */
310 for (i
= 0; i
< table
->nr_entries
; i
++) {
311 if (entries
[i
].addr
+ entries
[i
].size
< entries
[i
].addr
)
315 /* Create pointers for initial change-point information (for sorting): */
316 for (i
= 0; i
< 2 * table
->nr_entries
; i
++)
317 change_point
[i
] = &change_point_list
[i
];
320 * Record all known change-points (starting and ending addresses),
321 * omitting empty memory regions:
324 for (i
= 0; i
< table
->nr_entries
; i
++) {
325 if (entries
[i
].size
!= 0) {
326 change_point
[chg_idx
]->addr
= entries
[i
].addr
;
327 change_point
[chg_idx
++]->entry
= &entries
[i
];
328 change_point
[chg_idx
]->addr
= entries
[i
].addr
+ entries
[i
].size
;
329 change_point
[chg_idx
++]->entry
= &entries
[i
];
334 /* Sort change-point list by memory addresses (low -> high): */
335 sort(change_point
, chg_nr
, sizeof(*change_point
), cpcompare
, NULL
);
337 /* Create a new memory map, removing overlaps: */
338 overlap_entries
= 0; /* Number of entries in the overlap table */
339 new_nr_entries
= 0; /* Index for creating new map entries */
340 last_type
= 0; /* Start with undefined memory type */
341 last_addr
= 0; /* Start with 0 as last starting address */
343 /* Loop through change-points, determining effect on the new map: */
344 for (chg_idx
= 0; chg_idx
< chg_nr
; chg_idx
++) {
345 /* Keep track of all overlapping entries */
346 if (change_point
[chg_idx
]->addr
== change_point
[chg_idx
]->entry
->addr
) {
347 /* Add map entry to overlap list (> 1 entry implies an overlap) */
348 overlap_list
[overlap_entries
++] = change_point
[chg_idx
]->entry
;
350 /* Remove entry from list (order independent, so swap with last): */
351 for (i
= 0; i
< overlap_entries
; i
++) {
352 if (overlap_list
[i
] == change_point
[chg_idx
]->entry
)
353 overlap_list
[i
] = overlap_list
[overlap_entries
-1];
358 * If there are overlapping entries, decide which
359 * "type" to use (larger value takes precedence --
360 * 1=usable, 2,3,4,4+=unusable)
363 for (i
= 0; i
< overlap_entries
; i
++) {
364 if (overlap_list
[i
]->type
> current_type
)
365 current_type
= overlap_list
[i
]->type
;
368 /* Continue building up new map based on this information: */
369 if (current_type
!= last_type
|| current_type
== E820_TYPE_PRAM
) {
370 if (last_type
!= 0) {
371 new_entries
[new_nr_entries
].size
= change_point
[chg_idx
]->addr
- last_addr
;
372 /* Move forward only if the new size was non-zero: */
373 if (new_entries
[new_nr_entries
].size
!= 0)
374 /* No more space left for new entries? */
375 if (++new_nr_entries
>= max_nr_entries
)
378 if (current_type
!= 0) {
379 new_entries
[new_nr_entries
].addr
= change_point
[chg_idx
]->addr
;
380 new_entries
[new_nr_entries
].type
= current_type
;
381 last_addr
= change_point
[chg_idx
]->addr
;
383 last_type
= current_type
;
387 /* Copy the new entries into the original location: */
388 memcpy(entries
, new_entries
, new_nr_entries
*sizeof(*entries
));
389 table
->nr_entries
= new_nr_entries
;
394 static int __init
__append_e820_table(struct boot_e820_entry
*entries
, u32 nr_entries
)
396 struct boot_e820_entry
*entry
= entries
;
399 u64 start
= entry
->addr
;
400 u64 size
= entry
->size
;
401 u64 end
= start
+ size
- 1;
402 u32 type
= entry
->type
;
404 /* Ignore the entry on 64-bit overflow: */
405 if (start
> end
&& likely(size
))
408 e820__range_add(start
, size
, type
);
417 * Copy the BIOS E820 map into a safe place.
419 * Sanity-check it while we're at it..
421 * If we're lucky and live on a modern system, the setup code
422 * will have given us a memory map that we can use to properly
423 * set up memory. If we aren't, we'll fake a memory map.
425 static int __init
append_e820_table(struct boot_e820_entry
*entries
, u32 nr_entries
)
427 /* Only one memory region (or negative)? Ignore it */
431 return __append_e820_table(entries
, nr_entries
);
435 __e820__range_update(struct e820_table
*table
, u64 start
, u64 size
, enum e820_type old_type
, enum e820_type new_type
)
439 u64 real_updated_size
= 0;
441 BUG_ON(old_type
== new_type
);
443 if (size
> (ULLONG_MAX
- start
))
444 size
= ULLONG_MAX
- start
;
447 printk(KERN_DEBUG
"e820: update [mem %#010Lx-%#010Lx] ", start
, end
- 1);
448 e820_print_type(old_type
);
450 e820_print_type(new_type
);
453 for (i
= 0; i
< table
->nr_entries
; i
++) {
454 struct e820_entry
*entry
= &table
->entries
[i
];
455 u64 final_start
, final_end
;
458 if (entry
->type
!= old_type
)
461 entry_end
= entry
->addr
+ entry
->size
;
463 /* Completely covered by new range? */
464 if (entry
->addr
>= start
&& entry_end
<= end
) {
465 entry
->type
= new_type
;
466 real_updated_size
+= entry
->size
;
470 /* New range is completely covered? */
471 if (entry
->addr
< start
&& entry_end
> end
) {
472 __e820__range_add(table
, start
, size
, new_type
);
473 __e820__range_add(table
, end
, entry_end
- end
, entry
->type
);
474 entry
->size
= start
- entry
->addr
;
475 real_updated_size
+= size
;
479 /* Partially covered: */
480 final_start
= max(start
, entry
->addr
);
481 final_end
= min(end
, entry_end
);
482 if (final_start
>= final_end
)
485 __e820__range_add(table
, final_start
, final_end
- final_start
, new_type
);
487 real_updated_size
+= final_end
- final_start
;
490 * Left range could be head or tail, so need to update
493 entry
->size
-= final_end
- final_start
;
494 if (entry
->addr
< final_start
)
497 entry
->addr
= final_end
;
499 return real_updated_size
;
502 u64 __init
e820__range_update(u64 start
, u64 size
, enum e820_type old_type
, enum e820_type new_type
)
504 return __e820__range_update(e820_table
, start
, size
, old_type
, new_type
);
507 static u64 __init
e820__range_update_kexec(u64 start
, u64 size
, enum e820_type old_type
, enum e820_type new_type
)
509 return __e820__range_update(e820_table_kexec
, start
, size
, old_type
, new_type
);
512 /* Remove a range of memory from the E820 table: */
513 u64 __init
e820__range_remove(u64 start
, u64 size
, enum e820_type old_type
, bool check_type
)
517 u64 real_removed_size
= 0;
519 if (size
> (ULLONG_MAX
- start
))
520 size
= ULLONG_MAX
- start
;
523 printk(KERN_DEBUG
"e820: remove [mem %#010Lx-%#010Lx] ", start
, end
- 1);
525 e820_print_type(old_type
);
528 for (i
= 0; i
< e820_table
->nr_entries
; i
++) {
529 struct e820_entry
*entry
= &e820_table
->entries
[i
];
530 u64 final_start
, final_end
;
533 if (check_type
&& entry
->type
!= old_type
)
536 entry_end
= entry
->addr
+ entry
->size
;
538 /* Completely covered? */
539 if (entry
->addr
>= start
&& entry_end
<= end
) {
540 real_removed_size
+= entry
->size
;
541 memset(entry
, 0, sizeof(*entry
));
545 /* Is the new range completely covered? */
546 if (entry
->addr
< start
&& entry_end
> end
) {
547 e820__range_add(end
, entry_end
- end
, entry
->type
);
548 entry
->size
= start
- entry
->addr
;
549 real_removed_size
+= size
;
553 /* Partially covered: */
554 final_start
= max(start
, entry
->addr
);
555 final_end
= min(end
, entry_end
);
556 if (final_start
>= final_end
)
559 real_removed_size
+= final_end
- final_start
;
562 * Left range could be head or tail, so need to update
565 entry
->size
-= final_end
- final_start
;
566 if (entry
->addr
< final_start
)
569 entry
->addr
= final_end
;
571 return real_removed_size
;
574 void __init
e820__update_table_print(void)
576 if (e820__update_table(e820_table
))
579 pr_info("modified physical RAM map:\n");
580 e820__print_table("modified");
583 static void __init
e820__update_table_kexec(void)
585 e820__update_table(e820_table_kexec
);
588 #define MAX_GAP_END 0x100000000ull
591 * Search for a gap in the E820 memory space from 0 to MAX_GAP_END (4GB).
593 static int __init
e820_search_gap(unsigned long *gapstart
, unsigned long *gapsize
)
595 unsigned long long last
= MAX_GAP_END
;
596 int i
= e820_table
->nr_entries
;
600 unsigned long long start
= e820_table
->entries
[i
].addr
;
601 unsigned long long end
= start
+ e820_table
->entries
[i
].size
;
604 * Since "last" is at most 4GB, we know we'll
605 * fit in 32 bits if this condition is true:
608 unsigned long gap
= last
- end
;
610 if (gap
>= *gapsize
) {
623 * Search for the biggest gap in the low 32 bits of the E820
624 * memory space. We pass this space to the PCI subsystem, so
625 * that it can assign MMIO resources for hotplug or
626 * unconfigured devices in.
628 * Hopefully the BIOS let enough space left.
630 __init
void e820__setup_pci_gap(void)
632 unsigned long gapstart
, gapsize
;
636 found
= e820_search_gap(&gapstart
, &gapsize
);
640 gapstart
= (max_pfn
<< PAGE_SHIFT
) + 1024*1024;
641 pr_err("Cannot find an available gap in the 32-bit address range\n");
642 pr_err("PCI devices with unassigned 32-bit BARs may not work!\n");
644 gapstart
= 0x10000000;
649 * e820__reserve_resources_late() protects stolen RAM already:
651 pci_mem_start
= gapstart
;
653 pr_info("[mem %#010lx-%#010lx] available for PCI devices\n",
654 gapstart
, gapstart
+ gapsize
- 1);
658 * Called late during init, in free_initmem().
660 * Initial e820_table and e820_table_kexec are largish __initdata arrays.
662 * Copy them to a (usually much smaller) dynamically allocated area that is
663 * sized precisely after the number of e820 entries.
665 * This is done after we've performed all the fixes and tweaks to the tables.
666 * All functions which modify them are __init functions, which won't exist
667 * after free_initmem().
669 __init
void e820__reallocate_tables(void)
671 struct e820_table
*n
;
674 size
= offsetof(struct e820_table
, entries
) + sizeof(struct e820_entry
)*e820_table
->nr_entries
;
675 n
= kmalloc(size
, GFP_KERNEL
);
677 memcpy(n
, e820_table
, size
);
680 size
= offsetof(struct e820_table
, entries
) + sizeof(struct e820_entry
)*e820_table_kexec
->nr_entries
;
681 n
= kmalloc(size
, GFP_KERNEL
);
683 memcpy(n
, e820_table_kexec
, size
);
684 e820_table_kexec
= n
;
686 size
= offsetof(struct e820_table
, entries
) + sizeof(struct e820_entry
)*e820_table_firmware
->nr_entries
;
687 n
= kmalloc(size
, GFP_KERNEL
);
689 memcpy(n
, e820_table_firmware
, size
);
690 e820_table_firmware
= n
;
694 * Because of the small fixed size of struct boot_params, only the first
695 * 128 E820 memory entries are passed to the kernel via boot_params.e820_table,
696 * the remaining (if any) entries are passed via the SETUP_E820_EXT node of
697 * struct setup_data, which is parsed here.
699 void __init
e820__memory_setup_extended(u64 phys_addr
, u32 data_len
)
702 struct boot_e820_entry
*extmap
;
703 struct setup_data
*sdata
;
705 sdata
= early_memremap(phys_addr
, data_len
);
706 entries
= sdata
->len
/ sizeof(*extmap
);
707 extmap
= (struct boot_e820_entry
*)(sdata
->data
);
709 __append_e820_table(extmap
, entries
);
710 e820__update_table(e820_table
);
712 memcpy(e820_table_kexec
, e820_table
, sizeof(*e820_table_kexec
));
713 memcpy(e820_table_firmware
, e820_table
, sizeof(*e820_table_firmware
));
715 early_memunmap(sdata
, data_len
);
716 pr_info("extended physical RAM map:\n");
717 e820__print_table("extended");
721 * Find the ranges of physical addresses that do not correspond to
722 * E820 RAM areas and register the corresponding pages as 'nosave' for
723 * hibernation (32-bit) or software suspend and suspend to RAM (64-bit).
725 * This function requires the E820 map to be sorted and without any
726 * overlapping entries.
728 void __init
e820__register_nosave_regions(unsigned long limit_pfn
)
731 unsigned long pfn
= 0;
733 for (i
= 0; i
< e820_table
->nr_entries
; i
++) {
734 struct e820_entry
*entry
= &e820_table
->entries
[i
];
736 if (pfn
< PFN_UP(entry
->addr
))
737 register_nosave_region(pfn
, PFN_UP(entry
->addr
));
739 pfn
= PFN_DOWN(entry
->addr
+ entry
->size
);
741 if (entry
->type
!= E820_TYPE_RAM
&& entry
->type
!= E820_TYPE_RESERVED_KERN
)
742 register_nosave_region(PFN_UP(entry
->addr
), pfn
);
744 if (pfn
>= limit_pfn
)
751 * Register ACPI NVS memory regions, so that we can save/restore them during
752 * hibernation and the subsequent resume:
754 static int __init
e820__register_nvs_regions(void)
758 for (i
= 0; i
< e820_table
->nr_entries
; i
++) {
759 struct e820_entry
*entry
= &e820_table
->entries
[i
];
761 if (entry
->type
== E820_TYPE_NVS
)
762 acpi_nvs_register(entry
->addr
, entry
->size
);
767 core_initcall(e820__register_nvs_regions
);
771 * Allocate the requested number of bytes with the requsted alignment
772 * and return (the physical address) to the caller. Also register this
773 * range in the 'kexec' E820 table as a reserved range.
775 * This allows kexec to fake a new mptable, as if it came from the real
778 u64 __init
e820__memblock_alloc_reserved(u64 size
, u64 align
)
782 addr
= __memblock_alloc_base(size
, align
, MEMBLOCK_ALLOC_ACCESSIBLE
);
784 e820__range_update_kexec(addr
, size
, E820_TYPE_RAM
, E820_TYPE_RESERVED
);
785 pr_info("update e820_table_kexec for e820__memblock_alloc_reserved()\n");
786 e820__update_table_kexec();
793 # ifdef CONFIG_X86_PAE
794 # define MAX_ARCH_PFN (1ULL<<(36-PAGE_SHIFT))
796 # define MAX_ARCH_PFN (1ULL<<(32-PAGE_SHIFT))
798 #else /* CONFIG_X86_32 */
799 # define MAX_ARCH_PFN MAXMEM>>PAGE_SHIFT
803 * Find the highest page frame number we have available
805 static unsigned long __init
e820_end_pfn(unsigned long limit_pfn
, enum e820_type type
)
808 unsigned long last_pfn
= 0;
809 unsigned long max_arch_pfn
= MAX_ARCH_PFN
;
811 for (i
= 0; i
< e820_table
->nr_entries
; i
++) {
812 struct e820_entry
*entry
= &e820_table
->entries
[i
];
813 unsigned long start_pfn
;
814 unsigned long end_pfn
;
816 if (entry
->type
!= type
)
819 start_pfn
= entry
->addr
>> PAGE_SHIFT
;
820 end_pfn
= (entry
->addr
+ entry
->size
) >> PAGE_SHIFT
;
822 if (start_pfn
>= limit_pfn
)
824 if (end_pfn
> limit_pfn
) {
825 last_pfn
= limit_pfn
;
828 if (end_pfn
> last_pfn
)
832 if (last_pfn
> max_arch_pfn
)
833 last_pfn
= max_arch_pfn
;
835 pr_info("last_pfn = %#lx max_arch_pfn = %#lx\n",
836 last_pfn
, max_arch_pfn
);
840 unsigned long __init
e820__end_of_ram_pfn(void)
842 return e820_end_pfn(MAX_ARCH_PFN
, E820_TYPE_RAM
);
845 unsigned long __init
e820__end_of_low_ram_pfn(void)
847 return e820_end_pfn(1UL << (32 - PAGE_SHIFT
), E820_TYPE_RAM
);
850 static void __init
early_panic(char *msg
)
856 static int userdef __initdata
;
858 /* The "mem=nopentium" boot option disables 4MB page tables on 32-bit kernels: */
859 static int __init
parse_memopt(char *p
)
866 if (!strcmp(p
, "nopentium")) {
868 setup_clear_cpu_cap(X86_FEATURE_PSE
);
871 pr_warn("mem=nopentium ignored! (only supported on x86_32)\n");
877 mem_size
= memparse(p
, &p
);
879 /* Don't remove all memory when getting "mem={invalid}" parameter: */
883 e820__range_remove(mem_size
, ULLONG_MAX
- mem_size
, E820_TYPE_RAM
, 1);
887 early_param("mem", parse_memopt
);
889 static int __init
parse_memmap_one(char *p
)
892 u64 start_at
, mem_size
;
897 if (!strncmp(p
, "exactmap", 8)) {
898 #ifdef CONFIG_CRASH_DUMP
900 * If we are doing a crash dump, we still need to know
901 * the real memory size before the original memory map is
904 saved_max_pfn
= e820__end_of_ram_pfn();
906 e820_table
->nr_entries
= 0;
912 mem_size
= memparse(p
, &p
);
918 start_at
= memparse(p
+1, &p
);
919 e820__range_add(start_at
, mem_size
, E820_TYPE_RAM
);
920 } else if (*p
== '#') {
921 start_at
= memparse(p
+1, &p
);
922 e820__range_add(start_at
, mem_size
, E820_TYPE_ACPI
);
923 } else if (*p
== '$') {
924 start_at
= memparse(p
+1, &p
);
925 e820__range_add(start_at
, mem_size
, E820_TYPE_RESERVED
);
926 } else if (*p
== '!') {
927 start_at
= memparse(p
+1, &p
);
928 e820__range_add(start_at
, mem_size
, E820_TYPE_PRAM
);
929 } else if (*p
== '%') {
930 enum e820_type from
= 0, to
= 0;
932 start_at
= memparse(p
+ 1, &p
);
934 from
= simple_strtoull(p
+ 1, &p
, 0);
936 to
= simple_strtoull(p
+ 1, &p
, 0);
940 e820__range_update(start_at
, mem_size
, from
, to
);
942 e820__range_add(start_at
, mem_size
, to
);
944 e820__range_remove(start_at
, mem_size
, from
, 1);
946 e820__range_remove(start_at
, mem_size
, 0, 0);
948 e820__range_remove(mem_size
, ULLONG_MAX
- mem_size
, E820_TYPE_RAM
, 1);
951 return *p
== '\0' ? 0 : -EINVAL
;
954 static int __init
parse_memmap_opt(char *str
)
957 char *k
= strchr(str
, ',');
962 parse_memmap_one(str
);
968 early_param("memmap", parse_memmap_opt
);
971 * Reserve all entries from the bootloader's extensible data nodes list,
972 * because if present we are going to use it later on to fetch e820
975 void __init
e820__reserve_setup_data(void)
977 struct setup_data
*data
;
980 pa_data
= boot_params
.hdr
.setup_data
;
985 data
= early_memremap(pa_data
, sizeof(*data
));
986 e820__range_update(pa_data
, sizeof(*data
)+data
->len
, E820_TYPE_RAM
, E820_TYPE_RESERVED_KERN
);
987 e820__range_update_kexec(pa_data
, sizeof(*data
)+data
->len
, E820_TYPE_RAM
, E820_TYPE_RESERVED_KERN
);
988 pa_data
= data
->next
;
989 early_memunmap(data
, sizeof(*data
));
992 e820__update_table(e820_table
);
993 e820__update_table(e820_table_kexec
);
995 pr_info("extended physical RAM map:\n");
996 e820__print_table("reserve setup_data");
1000 * Called after parse_early_param(), after early parameters (such as mem=)
1001 * have been processed, in which case we already have an E820 table filled in
1002 * via the parameter callback function(s), but it's not sorted and printed yet:
1004 void __init
e820__finish_early_params(void)
1007 if (e820__update_table(e820_table
) < 0)
1008 early_panic("Invalid user supplied memory map");
1010 pr_info("user-defined physical RAM map:\n");
1011 e820__print_table("user");
1015 static const char *__init
e820_type_to_string(struct e820_entry
*entry
)
1017 switch (entry
->type
) {
1018 case E820_TYPE_RESERVED_KERN
: /* Fall-through: */
1019 case E820_TYPE_RAM
: return "System RAM";
1020 case E820_TYPE_ACPI
: return "ACPI Tables";
1021 case E820_TYPE_NVS
: return "ACPI Non-volatile Storage";
1022 case E820_TYPE_UNUSABLE
: return "Unusable memory";
1023 case E820_TYPE_PRAM
: return "Persistent Memory (legacy)";
1024 case E820_TYPE_PMEM
: return "Persistent Memory";
1025 case E820_TYPE_RESERVED
: return "Reserved";
1026 default: return "Unknown E820 type";
1030 static unsigned long __init
e820_type_to_iomem_type(struct e820_entry
*entry
)
1032 switch (entry
->type
) {
1033 case E820_TYPE_RESERVED_KERN
: /* Fall-through: */
1034 case E820_TYPE_RAM
: return IORESOURCE_SYSTEM_RAM
;
1035 case E820_TYPE_ACPI
: /* Fall-through: */
1036 case E820_TYPE_NVS
: /* Fall-through: */
1037 case E820_TYPE_UNUSABLE
: /* Fall-through: */
1038 case E820_TYPE_PRAM
: /* Fall-through: */
1039 case E820_TYPE_PMEM
: /* Fall-through: */
1040 case E820_TYPE_RESERVED
: /* Fall-through: */
1041 default: return IORESOURCE_MEM
;
1045 static unsigned long __init
e820_type_to_iores_desc(struct e820_entry
*entry
)
1047 switch (entry
->type
) {
1048 case E820_TYPE_ACPI
: return IORES_DESC_ACPI_TABLES
;
1049 case E820_TYPE_NVS
: return IORES_DESC_ACPI_NV_STORAGE
;
1050 case E820_TYPE_PMEM
: return IORES_DESC_PERSISTENT_MEMORY
;
1051 case E820_TYPE_PRAM
: return IORES_DESC_PERSISTENT_MEMORY_LEGACY
;
1052 case E820_TYPE_RESERVED_KERN
: /* Fall-through: */
1053 case E820_TYPE_RAM
: /* Fall-through: */
1054 case E820_TYPE_UNUSABLE
: /* Fall-through: */
1055 case E820_TYPE_RESERVED
: /* Fall-through: */
1056 default: return IORES_DESC_NONE
;
1060 static bool __init
do_mark_busy(enum e820_type type
, struct resource
*res
)
1062 /* this is the legacy bios/dos rom-shadow + mmio region */
1063 if (res
->start
< (1ULL<<20))
1067 * Treat persistent memory like device memory, i.e. reserve it
1068 * for exclusive use of a driver
1071 case E820_TYPE_RESERVED
:
1072 case E820_TYPE_PRAM
:
1073 case E820_TYPE_PMEM
:
1075 case E820_TYPE_RESERVED_KERN
:
1077 case E820_TYPE_ACPI
:
1079 case E820_TYPE_UNUSABLE
:
1086 * Mark E820 reserved areas as busy for the resource manager:
1089 static struct resource __initdata
*e820_res
;
1091 void __init
e820__reserve_resources(void)
1094 struct resource
*res
;
1097 res
= alloc_bootmem(sizeof(*res
) * e820_table
->nr_entries
);
1100 for (i
= 0; i
< e820_table
->nr_entries
; i
++) {
1101 struct e820_entry
*entry
= e820_table
->entries
+ i
;
1103 end
= entry
->addr
+ entry
->size
- 1;
1104 if (end
!= (resource_size_t
)end
) {
1108 res
->start
= entry
->addr
;
1110 res
->name
= e820_type_to_string(entry
);
1111 res
->flags
= e820_type_to_iomem_type(entry
);
1112 res
->desc
= e820_type_to_iores_desc(entry
);
1115 * Don't register the region that could be conflicted with
1116 * PCI device BAR resources and insert them later in
1117 * pcibios_resource_survey():
1119 if (do_mark_busy(entry
->type
, res
)) {
1120 res
->flags
|= IORESOURCE_BUSY
;
1121 insert_resource(&iomem_resource
, res
);
1126 /* Expose the bootloader-provided memory layout to the sysfs. */
1127 for (i
= 0; i
< e820_table_firmware
->nr_entries
; i
++) {
1128 struct e820_entry
*entry
= e820_table_firmware
->entries
+ i
;
1130 firmware_map_add_early(entry
->addr
, entry
->addr
+ entry
->size
, e820_type_to_string(entry
));
1135 * How much should we pad the end of RAM, depending on where it is?
1137 static unsigned long __init
ram_alignment(resource_size_t pos
)
1139 unsigned long mb
= pos
>> 20;
1141 /* To 64kB in the first megabyte */
1145 /* To 1MB in the first 16MB */
1149 /* To 64MB for anything above that */
1150 return 64*1024*1024;
1153 #define MAX_RESOURCE_SIZE ((resource_size_t)-1)
1155 void __init
e820__reserve_resources_late(void)
1158 struct resource
*res
;
1161 for (i
= 0; i
< e820_table
->nr_entries
; i
++) {
1162 if (!res
->parent
&& res
->end
)
1163 insert_resource_expand_to_fit(&iomem_resource
, res
);
1168 * Try to bump up RAM regions to reasonable boundaries, to
1171 for (i
= 0; i
< e820_table
->nr_entries
; i
++) {
1172 struct e820_entry
*entry
= &e820_table
->entries
[i
];
1175 if (entry
->type
!= E820_TYPE_RAM
)
1178 start
= entry
->addr
+ entry
->size
;
1179 end
= round_up(start
, ram_alignment(start
)) - 1;
1180 if (end
> MAX_RESOURCE_SIZE
)
1181 end
= MAX_RESOURCE_SIZE
;
1185 printk(KERN_DEBUG
"e820: reserve RAM buffer [mem %#010llx-%#010llx]\n", start
, end
);
1186 reserve_region_with_split(&iomem_resource
, start
, end
, "RAM buffer");
1191 * Pass the firmware (bootloader) E820 map to the kernel and process it:
1193 char *__init
e820__memory_setup_default(void)
1195 char *who
= "BIOS-e820";
1198 * Try to copy the BIOS-supplied E820-map.
1200 * Otherwise fake a memory map; one section from 0k->640k,
1201 * the next section from 1mb->appropriate_mem_k
1203 if (append_e820_table(boot_params
.e820_table
, boot_params
.e820_entries
) < 0) {
1206 /* Compare results from other methods and take the one that gives more RAM: */
1207 if (boot_params
.alt_mem_k
< boot_params
.screen_info
.ext_mem_k
) {
1208 mem_size
= boot_params
.screen_info
.ext_mem_k
;
1211 mem_size
= boot_params
.alt_mem_k
;
1215 e820_table
->nr_entries
= 0;
1216 e820__range_add(0, LOWMEMSIZE(), E820_TYPE_RAM
);
1217 e820__range_add(HIGH_MEMORY
, mem_size
<< 10, E820_TYPE_RAM
);
1220 /* We just appended a lot of ranges, sanitize the table: */
1221 e820__update_table(e820_table
);
1227 * Calls e820__memory_setup_default() in essence to pick up the firmware/bootloader
1228 * E820 map - with an optional platform quirk available for virtual platforms
1229 * to override this method of boot environment processing:
1231 void __init
e820__memory_setup(void)
1235 /* This is a firmware interface ABI - make sure we don't break it: */
1236 BUILD_BUG_ON(sizeof(struct boot_e820_entry
) != 20);
1238 who
= x86_init
.resources
.memory_setup();
1240 memcpy(e820_table_kexec
, e820_table
, sizeof(*e820_table_kexec
));
1241 memcpy(e820_table_firmware
, e820_table
, sizeof(*e820_table_firmware
));
1243 pr_info("BIOS-provided physical RAM map:\n");
1244 e820__print_table(who
);
1247 void __init
e820__memblock_setup(void)
1254 * The bootstrap memblock region count maximum is 128 entries
1255 * (INIT_MEMBLOCK_REGIONS), but EFI might pass us more E820 entries
1256 * than that - so allow memblock resizing.
1258 * This is safe, because this call happens pretty late during x86 setup,
1259 * so we know about reserved memory regions already. (This is important
1260 * so that memblock resizing does no stomp over reserved areas.)
1262 memblock_allow_resize();
1264 for (i
= 0; i
< e820_table
->nr_entries
; i
++) {
1265 struct e820_entry
*entry
= &e820_table
->entries
[i
];
1267 end
= entry
->addr
+ entry
->size
;
1268 if (addr
< entry
->addr
)
1269 memblock_reserve(addr
, entry
->addr
- addr
);
1271 if (end
!= (resource_size_t
)end
)
1275 * all !E820_TYPE_RAM ranges (including gap ranges) are put
1276 * into memblock.reserved to make sure that struct pages in
1277 * such regions are not left uninitialized after bootup.
1279 if (entry
->type
!= E820_TYPE_RAM
&& entry
->type
!= E820_TYPE_RESERVED_KERN
)
1280 memblock_reserve(entry
->addr
, entry
->size
);
1282 memblock_add(entry
->addr
, entry
->size
);
1285 /* Throw away partial pages: */
1286 memblock_trim_memory(PAGE_SIZE
);
1288 memblock_dump_all();