2 * Handle the memory map.
3 * The functions here do the job until bootmem takes over.
5 * Getting sanitize_e820_map() in sync with i386 version by applying change:
6 * - Provisions for empty E820 memory regions (reported by certain BIOSes).
7 * Alex Achenbach <xela@slit.de>, December 2002.
8 * Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
11 #include <linux/kernel.h>
12 #include <linux/types.h>
13 #include <linux/init.h>
14 #include <linux/bootmem.h>
15 #include <linux/ioport.h>
16 #include <linux/string.h>
17 #include <linux/kexec.h>
18 #include <linux/module.h>
20 #include <asm/pgtable.h>
23 #include <asm/proto.h>
24 #include <asm/bootsetup.h>
25 #include <asm/sections.h>
28 * PFN of last memory page.
30 unsigned long end_pfn
;
31 EXPORT_SYMBOL(end_pfn
);
34 * end_pfn only includes RAM, while end_pfn_map includes all e820 entries.
35 * The direct mapping extends to end_pfn_map, so that we can directly access
36 * apertures, ACPI and other tables without having to play with fixmaps.
38 unsigned long end_pfn_map
;
41 * Last pfn which the user wants to use.
43 unsigned long end_user_pfn
= MAXMEM
>>PAGE_SHIFT
;
45 extern struct resource code_resource
, data_resource
;
47 /* Check for some hardcoded bad areas that early boot is not allowed to touch */
48 static inline int bad_addr(unsigned long *addrp
, unsigned long size
)
50 unsigned long addr
= *addrp
, last
= addr
+ size
;
52 /* various gunk below that needed for SMP startup */
58 /* direct mapping tables of the kernel */
59 if (last
>= table_start
<<PAGE_SHIFT
&& addr
< table_end
<<PAGE_SHIFT
) {
60 *addrp
= table_end
<< PAGE_SHIFT
;
65 #ifdef CONFIG_BLK_DEV_INITRD
66 if (LOADER_TYPE
&& INITRD_START
&& last
>= INITRD_START
&&
67 addr
< INITRD_START
+INITRD_SIZE
) {
68 *addrp
= INITRD_START
+ INITRD_SIZE
;
72 /* kernel code + 640k memory hole (later should not be needed, but
73 be paranoid for now) */
74 if (last
>= 640*1024 && addr
< __pa_symbol(&_end
)) {
75 *addrp
= __pa_symbol(&_end
);
79 if (last
>= ebda_addr
&& addr
< ebda_addr
+ ebda_size
) {
80 *addrp
= ebda_addr
+ ebda_size
;
84 /* XXX ramdisk image here? */
89 * This function checks if any part of the range <start,end> is mapped
93 e820_any_mapped(unsigned long start
, unsigned long end
, unsigned type
)
96 for (i
= 0; i
< e820
.nr_map
; i
++) {
97 struct e820entry
*ei
= &e820
.map
[i
];
98 if (type
&& ei
->type
!= type
)
100 if (ei
->addr
>= end
|| ei
->addr
+ ei
->size
<= start
)
108 * This function checks if the entire range <start,end> is mapped with type.
110 * Note: this function only works correct if the e820 table is sorted and
111 * not-overlapping, which is the case
113 int __init
e820_all_mapped(unsigned long start
, unsigned long end
, unsigned type
)
116 for (i
= 0; i
< e820
.nr_map
; i
++) {
117 struct e820entry
*ei
= &e820
.map
[i
];
118 if (type
&& ei
->type
!= type
)
120 /* is the region (part) in overlap with the current region ?*/
121 if (ei
->addr
>= end
|| ei
->addr
+ ei
->size
<= start
)
124 /* if the region is at the beginning of <start,end> we move
125 * start to the end of the region since it's ok until there
127 if (ei
->addr
<= start
)
128 start
= ei
->addr
+ ei
->size
;
129 /* if start is now at or beyond end, we're done, full coverage */
131 return 1; /* we're done */
137 * Find a free area in a specific range.
139 unsigned long __init
find_e820_area(unsigned long start
, unsigned long end
, unsigned size
)
142 for (i
= 0; i
< e820
.nr_map
; i
++) {
143 struct e820entry
*ei
= &e820
.map
[i
];
144 unsigned long addr
= ei
->addr
, last
;
145 if (ei
->type
!= E820_RAM
)
149 if (addr
> ei
->addr
+ ei
->size
)
151 while (bad_addr(&addr
, size
) && addr
+size
<= ei
->addr
+ei
->size
)
154 if (last
> ei
->addr
+ ei
->size
)
164 * Free bootmem based on the e820 table for a node.
166 void __init
e820_bootmem_free(pg_data_t
*pgdat
, unsigned long start
,unsigned long end
)
169 for (i
= 0; i
< e820
.nr_map
; i
++) {
170 struct e820entry
*ei
= &e820
.map
[i
];
171 unsigned long last
, addr
;
173 if (ei
->type
!= E820_RAM
||
174 ei
->addr
+ei
->size
<= start
||
178 addr
= round_up(ei
->addr
, PAGE_SIZE
);
182 last
= round_down(ei
->addr
+ ei
->size
, PAGE_SIZE
);
186 if (last
> addr
&& last
-addr
>= PAGE_SIZE
)
187 free_bootmem_node(pgdat
, addr
, last
-addr
);
192 * Find the highest page frame number we have available
194 unsigned long __init
e820_end_of_ram(void)
197 unsigned long end_pfn
= 0;
199 for (i
= 0; i
< e820
.nr_map
; i
++) {
200 struct e820entry
*ei
= &e820
.map
[i
];
201 unsigned long start
, end
;
203 start
= round_up(ei
->addr
, PAGE_SIZE
);
204 end
= round_down(ei
->addr
+ ei
->size
, PAGE_SIZE
);
207 if (ei
->type
== E820_RAM
) {
208 if (end
> end_pfn
<<PAGE_SHIFT
)
209 end_pfn
= end
>>PAGE_SHIFT
;
211 if (end
> end_pfn_map
<<PAGE_SHIFT
)
212 end_pfn_map
= end
>>PAGE_SHIFT
;
216 if (end_pfn
> end_pfn_map
)
217 end_pfn_map
= end_pfn
;
218 if (end_pfn_map
> MAXMEM
>>PAGE_SHIFT
)
219 end_pfn_map
= MAXMEM
>>PAGE_SHIFT
;
220 if (end_pfn
> end_user_pfn
)
221 end_pfn
= end_user_pfn
;
222 if (end_pfn
> end_pfn_map
)
223 end_pfn
= end_pfn_map
;
229 * Compute how much memory is missing in a range.
230 * Unlike the other functions in this file the arguments are in page numbers.
233 e820_hole_size(unsigned long start_pfn
, unsigned long end_pfn
)
235 unsigned long ram
= 0;
236 unsigned long start
= start_pfn
<< PAGE_SHIFT
;
237 unsigned long end
= end_pfn
<< PAGE_SHIFT
;
239 for (i
= 0; i
< e820
.nr_map
; i
++) {
240 struct e820entry
*ei
= &e820
.map
[i
];
241 unsigned long last
, addr
;
243 if (ei
->type
!= E820_RAM
||
244 ei
->addr
+ei
->size
<= start
||
248 addr
= round_up(ei
->addr
, PAGE_SIZE
);
252 last
= round_down(ei
->addr
+ ei
->size
, PAGE_SIZE
);
259 return ((end
- start
) - ram
) >> PAGE_SHIFT
;
263 * Mark e820 reserved areas as busy for the resource manager.
265 void __init
e820_reserve_resources(void)
268 for (i
= 0; i
< e820
.nr_map
; i
++) {
269 struct resource
*res
;
270 res
= alloc_bootmem_low(sizeof(struct resource
));
271 switch (e820
.map
[i
].type
) {
272 case E820_RAM
: res
->name
= "System RAM"; break;
273 case E820_ACPI
: res
->name
= "ACPI Tables"; break;
274 case E820_NVS
: res
->name
= "ACPI Non-volatile Storage"; break;
275 default: res
->name
= "reserved";
277 res
->start
= e820
.map
[i
].addr
;
278 res
->end
= res
->start
+ e820
.map
[i
].size
- 1;
279 res
->flags
= IORESOURCE_MEM
| IORESOURCE_BUSY
;
280 request_resource(&iomem_resource
, res
);
281 if (e820
.map
[i
].type
== E820_RAM
) {
283 * We don't know which RAM region contains kernel data,
284 * so we try it repeatedly and let the resource manager
287 request_resource(res
, &code_resource
);
288 request_resource(res
, &data_resource
);
290 request_resource(res
, &crashk_res
);
297 * Add a memory region to the kernel e820 map.
299 void __init
add_memory_region(unsigned long start
, unsigned long size
, int type
)
304 printk(KERN_ERR
"Ooops! Too many entries in the memory map!\n");
308 e820
.map
[x
].addr
= start
;
309 e820
.map
[x
].size
= size
;
310 e820
.map
[x
].type
= type
;
314 void __init
e820_print_map(char *who
)
318 for (i
= 0; i
< e820
.nr_map
; i
++) {
319 printk(" %s: %016Lx - %016Lx ", who
,
320 (unsigned long long) e820
.map
[i
].addr
,
321 (unsigned long long) (e820
.map
[i
].addr
+ e820
.map
[i
].size
));
322 switch (e820
.map
[i
].type
) {
323 case E820_RAM
: printk("(usable)\n");
326 printk("(reserved)\n");
329 printk("(ACPI data)\n");
332 printk("(ACPI NVS)\n");
334 default: printk("type %u\n", e820
.map
[i
].type
);
341 * Sanitize the BIOS e820 map.
343 * Some e820 responses include overlapping entries. The following
344 * replaces the original e820 map with a new one, removing overlaps.
347 static int __init
sanitize_e820_map(struct e820entry
* biosmap
, char * pnr_map
)
349 struct change_member
{
350 struct e820entry
*pbios
; /* pointer to original bios entry */
351 unsigned long long addr
; /* address for this change point */
353 static struct change_member change_point_list
[2*E820MAX
] __initdata
;
354 static struct change_member
*change_point
[2*E820MAX
] __initdata
;
355 static struct e820entry
*overlap_list
[E820MAX
] __initdata
;
356 static struct e820entry new_bios
[E820MAX
] __initdata
;
357 struct change_member
*change_tmp
;
358 unsigned long current_type
, last_type
;
359 unsigned long long last_addr
;
360 int chgidx
, still_changing
;
363 int old_nr
, new_nr
, chg_nr
;
367 Visually we're performing the following (1,2,3,4 = memory types)...
369 Sample memory map (w/overlaps):
370 ____22__________________
371 ______________________4_
372 ____1111________________
373 _44_____________________
374 11111111________________
375 ____________________33__
376 ___________44___________
377 __________33333_________
378 ______________22________
379 ___________________2222_
380 _________111111111______
381 _____________________11_
382 _________________4______
384 Sanitized equivalent (no overlap):
385 1_______________________
386 _44_____________________
387 ___1____________________
388 ____22__________________
389 ______11________________
390 _________1______________
391 __________3_____________
392 ___________44___________
393 _____________33_________
394 _______________2________
395 ________________1_______
396 _________________4______
397 ___________________2____
398 ____________________33__
399 ______________________4_
402 /* if there's only one memory region, don't bother */
408 /* bail out if we find any unreasonable addresses in bios map */
409 for (i
=0; i
<old_nr
; i
++)
410 if (biosmap
[i
].addr
+ biosmap
[i
].size
< biosmap
[i
].addr
)
413 /* create pointers for initial change-point information (for sorting) */
414 for (i
=0; i
< 2*old_nr
; i
++)
415 change_point
[i
] = &change_point_list
[i
];
417 /* record all known change-points (starting and ending addresses),
418 omitting those that are for empty memory regions */
420 for (i
=0; i
< old_nr
; i
++) {
421 if (biosmap
[i
].size
!= 0) {
422 change_point
[chgidx
]->addr
= biosmap
[i
].addr
;
423 change_point
[chgidx
++]->pbios
= &biosmap
[i
];
424 change_point
[chgidx
]->addr
= biosmap
[i
].addr
+ biosmap
[i
].size
;
425 change_point
[chgidx
++]->pbios
= &biosmap
[i
];
430 /* sort change-point list by memory addresses (low -> high) */
432 while (still_changing
) {
434 for (i
=1; i
< chg_nr
; i
++) {
435 /* if <current_addr> > <last_addr>, swap */
436 /* or, if current=<start_addr> & last=<end_addr>, swap */
437 if ((change_point
[i
]->addr
< change_point
[i
-1]->addr
) ||
438 ((change_point
[i
]->addr
== change_point
[i
-1]->addr
) &&
439 (change_point
[i
]->addr
== change_point
[i
]->pbios
->addr
) &&
440 (change_point
[i
-1]->addr
!= change_point
[i
-1]->pbios
->addr
))
443 change_tmp
= change_point
[i
];
444 change_point
[i
] = change_point
[i
-1];
445 change_point
[i
-1] = change_tmp
;
451 /* create a new bios memory map, removing overlaps */
452 overlap_entries
=0; /* number of entries in the overlap table */
453 new_bios_entry
=0; /* index for creating new bios map entries */
454 last_type
= 0; /* start with undefined memory type */
455 last_addr
= 0; /* start with 0 as last starting address */
456 /* loop through change-points, determining affect on the new bios map */
457 for (chgidx
=0; chgidx
< chg_nr
; chgidx
++)
459 /* keep track of all overlapping bios entries */
460 if (change_point
[chgidx
]->addr
== change_point
[chgidx
]->pbios
->addr
)
462 /* add map entry to overlap list (> 1 entry implies an overlap) */
463 overlap_list
[overlap_entries
++]=change_point
[chgidx
]->pbios
;
467 /* remove entry from list (order independent, so swap with last) */
468 for (i
=0; i
<overlap_entries
; i
++)
470 if (overlap_list
[i
] == change_point
[chgidx
]->pbios
)
471 overlap_list
[i
] = overlap_list
[overlap_entries
-1];
475 /* if there are overlapping entries, decide which "type" to use */
476 /* (larger value takes precedence -- 1=usable, 2,3,4,4+=unusable) */
478 for (i
=0; i
<overlap_entries
; i
++)
479 if (overlap_list
[i
]->type
> current_type
)
480 current_type
= overlap_list
[i
]->type
;
481 /* continue building up new bios map based on this information */
482 if (current_type
!= last_type
) {
483 if (last_type
!= 0) {
484 new_bios
[new_bios_entry
].size
=
485 change_point
[chgidx
]->addr
- last_addr
;
486 /* move forward only if the new size was non-zero */
487 if (new_bios
[new_bios_entry
].size
!= 0)
488 if (++new_bios_entry
>= E820MAX
)
489 break; /* no more space left for new bios entries */
491 if (current_type
!= 0) {
492 new_bios
[new_bios_entry
].addr
= change_point
[chgidx
]->addr
;
493 new_bios
[new_bios_entry
].type
= current_type
;
494 last_addr
=change_point
[chgidx
]->addr
;
496 last_type
= current_type
;
499 new_nr
= new_bios_entry
; /* retain count for new bios entries */
501 /* copy new bios mapping into original location */
502 memcpy(biosmap
, new_bios
, new_nr
*sizeof(struct e820entry
));
509 * Copy the BIOS e820 map into a safe place.
511 * Sanity-check it while we're at it..
513 * If we're lucky and live on a modern system, the setup code
514 * will have given us a memory map that we can use to properly
515 * set up memory. If we aren't, we'll fake a memory map.
517 * We check to see that the memory map contains at least 2 elements
518 * before we'll use it, because the detection code in setup.S may
519 * not be perfect and most every PC known to man has two memory
520 * regions: one from 0 to 640k, and one from 1mb up. (The IBM
521 * thinkpad 560x, for example, does not cooperate with the memory
524 static int __init
copy_e820_map(struct e820entry
* biosmap
, int nr_map
)
526 /* Only one memory region (or negative)? Ignore it */
531 unsigned long start
= biosmap
->addr
;
532 unsigned long size
= biosmap
->size
;
533 unsigned long end
= start
+ size
;
534 unsigned long type
= biosmap
->type
;
536 /* Overflow in 64 bits? Ignore the memory map. */
541 * Some BIOSes claim RAM in the 640k - 1M region.
542 * Not right. Fix it up.
544 * This should be removed on Hammer which is supposed to not
545 * have non e820 covered ISA mappings there, but I had some strange
546 * problems so it stays for now. -AK
548 if (type
== E820_RAM
) {
549 if (start
< 0x100000ULL
&& end
> 0xA0000ULL
) {
550 if (start
< 0xA0000ULL
)
551 add_memory_region(start
, 0xA0000ULL
-start
, type
);
552 if (end
<= 0x100000ULL
)
559 add_memory_region(start
, size
, type
);
560 } while (biosmap
++,--nr_map
);
564 void __init
setup_memory_region(void)
566 char *who
= "BIOS-e820";
569 * Try to copy the BIOS-supplied E820-map.
571 * Otherwise fake a memory map; one section from 0k->640k,
572 * the next section from 1mb->appropriate_mem_k
574 sanitize_e820_map(E820_MAP
, &E820_MAP_NR
);
575 if (copy_e820_map(E820_MAP
, E820_MAP_NR
) < 0) {
576 unsigned long mem_size
;
578 /* compare results from other methods and take the greater */
579 if (ALT_MEM_K
< EXT_MEM_K
) {
580 mem_size
= EXT_MEM_K
;
583 mem_size
= ALT_MEM_K
;
588 add_memory_region(0, LOWMEMSIZE(), E820_RAM
);
589 add_memory_region(HIGH_MEMORY
, mem_size
<< 10, E820_RAM
);
591 printk(KERN_INFO
"BIOS-provided physical RAM map:\n");
595 void __init
parse_memopt(char *p
, char **from
)
597 end_user_pfn
= memparse(p
, from
);
598 end_user_pfn
>>= PAGE_SHIFT
;
601 void __init
parse_memmapopt(char *p
, char **from
)
603 unsigned long long start_at
, mem_size
;
605 mem_size
= memparse(p
, from
);
608 start_at
= memparse(p
+1, from
);
609 add_memory_region(start_at
, mem_size
, E820_RAM
);
610 } else if (*p
== '#') {
611 start_at
= memparse(p
+1, from
);
612 add_memory_region(start_at
, mem_size
, E820_ACPI
);
613 } else if (*p
== '$') {
614 start_at
= memparse(p
+1, from
);
615 add_memory_region(start_at
, mem_size
, E820_RESERVED
);
617 end_user_pfn
= (mem_size
>> PAGE_SHIFT
);
622 unsigned long pci_mem_start
= 0xaeedbabe;
623 EXPORT_SYMBOL(pci_mem_start
);
626 * Search for the biggest gap in the low 32 bits of the e820
627 * memory space. We pass this space to PCI to assign MMIO resources
628 * for hotplug or unconfigured devices in.
629 * Hopefully the BIOS let enough space left.
631 __init
void e820_setup_gap(void)
633 unsigned long gapstart
, gapsize
, round
;
638 last
= 0x100000000ull
;
639 gapstart
= 0x10000000;
643 unsigned long long start
= e820
.map
[i
].addr
;
644 unsigned long long end
= start
+ e820
.map
[i
].size
;
647 * Since "last" is at most 4GB, we know we'll
648 * fit in 32 bits if this condition is true
651 unsigned long gap
= last
- end
;
664 gapstart
= (end_pfn
<< PAGE_SHIFT
) + 1024*1024;
665 printk(KERN_ERR
"PCI: Warning: Cannot find a gap in the 32bit address range\n"
666 KERN_ERR
"PCI: Unassigned devices with 32bit resource registers may break!\n");
670 * See how much we want to round up: start off with
671 * rounding to the next 1MB area.
674 while ((gapsize
>> 4) > round
)
676 /* Fun with two's complement */
677 pci_mem_start
= (gapstart
+ round
) & -round
;
679 printk(KERN_INFO
"Allocating PCI resources starting at %lx (gap: %lx:%lx)\n",
680 pci_mem_start
, gapstart
, gapsize
);