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 <linux/pfn.h>
22 #include <asm/pgtable.h>
25 #include <asm/setup.h>
29 /* For PCI or other memory-mapped resources */
30 unsigned long pci_mem_start
= 0xaeedbabe;
32 EXPORT_SYMBOL(pci_mem_start
);
36 * This function checks if any part of the range <start,end> is mapped
40 e820_any_mapped(u64 start
, u64 end
, unsigned type
)
44 for (i
= 0; i
< e820
.nr_map
; i
++) {
45 struct e820entry
*ei
= &e820
.map
[i
];
47 if (type
&& ei
->type
!= type
)
49 if (ei
->addr
>= end
|| ei
->addr
+ ei
->size
<= start
)
55 EXPORT_SYMBOL_GPL(e820_any_mapped
);
58 * This function checks if the entire range <start,end> is mapped with type.
60 * Note: this function only works correct if the e820 table is sorted and
61 * not-overlapping, which is the case
63 int __init
e820_all_mapped(u64 start
, u64 end
, unsigned type
)
67 for (i
= 0; i
< e820
.nr_map
; i
++) {
68 struct e820entry
*ei
= &e820
.map
[i
];
70 if (type
&& ei
->type
!= type
)
72 /* is the region (part) in overlap with the current region ?*/
73 if (ei
->addr
>= end
|| ei
->addr
+ ei
->size
<= start
)
76 /* if the region is at the beginning of <start,end> we move
77 * start to the end of the region since it's ok until there
79 if (ei
->addr
<= start
)
80 start
= ei
->addr
+ ei
->size
;
82 * if start is now at or beyond end, we're done, full
92 * Add a memory region to the kernel e820 map.
94 void __init
add_memory_region(u64 start
, u64 size
, int type
)
98 if (x
== ARRAY_SIZE(e820
.map
)) {
99 printk(KERN_ERR
"Ooops! Too many entries in the memory map!\n");
103 e820
.map
[x
].addr
= start
;
104 e820
.map
[x
].size
= size
;
105 e820
.map
[x
].type
= type
;
109 void __init
e820_print_map(char *who
)
113 for (i
= 0; i
< e820
.nr_map
; i
++) {
114 printk(KERN_INFO
" %s: %016Lx - %016Lx ", who
,
115 (unsigned long long) e820
.map
[i
].addr
,
117 (e820
.map
[i
].addr
+ e820
.map
[i
].size
));
118 switch (e820
.map
[i
].type
) {
120 printk(KERN_CONT
"(usable)\n");
123 printk(KERN_CONT
"(reserved)\n");
126 printk(KERN_CONT
"(ACPI data)\n");
129 printk(KERN_CONT
"(ACPI NVS)\n");
132 printk(KERN_CONT
"type %u\n", e820
.map
[i
].type
);
139 * Sanitize the BIOS e820 map.
141 * Some e820 responses include overlapping entries. The following
142 * replaces the original e820 map with a new one, removing overlaps.
145 int __init
sanitize_e820_map(struct e820entry
*biosmap
, int max_nr_map
,
148 struct change_member
{
149 struct e820entry
*pbios
; /* pointer to original bios entry */
150 unsigned long long addr
; /* address for this change point */
152 static struct change_member change_point_list
[2*E820MAX
] __initdata
;
153 static struct change_member
*change_point
[2*E820MAX
] __initdata
;
154 static struct e820entry
*overlap_list
[E820MAX
] __initdata
;
155 static struct e820entry new_bios
[E820MAX
] __initdata
;
156 struct change_member
*change_tmp
;
157 unsigned long current_type
, last_type
;
158 unsigned long long last_addr
;
159 int chgidx
, still_changing
;
162 int old_nr
, new_nr
, chg_nr
;
166 Visually we're performing the following
167 (1,2,3,4 = memory types)...
169 Sample memory map (w/overlaps):
170 ____22__________________
171 ______________________4_
172 ____1111________________
173 _44_____________________
174 11111111________________
175 ____________________33__
176 ___________44___________
177 __________33333_________
178 ______________22________
179 ___________________2222_
180 _________111111111______
181 _____________________11_
182 _________________4______
184 Sanitized equivalent (no overlap):
185 1_______________________
186 _44_____________________
187 ___1____________________
188 ____22__________________
189 ______11________________
190 _________1______________
191 __________3_____________
192 ___________44___________
193 _____________33_________
194 _______________2________
195 ________________1_______
196 _________________4______
197 ___________________2____
198 ____________________33__
199 ______________________4_
202 /* if there's only one memory region, don't bother */
208 /* bail out if we find any unreasonable addresses in bios map */
209 for (i
= 0; i
< old_nr
; i
++)
210 if (biosmap
[i
].addr
+ biosmap
[i
].size
< biosmap
[i
].addr
)
213 /* create pointers for initial change-point information (for sorting) */
214 for (i
= 0; i
< 2 * old_nr
; i
++)
215 change_point
[i
] = &change_point_list
[i
];
217 /* record all known change-points (starting and ending addresses),
218 omitting those that are for empty memory regions */
220 for (i
= 0; i
< old_nr
; i
++) {
221 if (biosmap
[i
].size
!= 0) {
222 change_point
[chgidx
]->addr
= biosmap
[i
].addr
;
223 change_point
[chgidx
++]->pbios
= &biosmap
[i
];
224 change_point
[chgidx
]->addr
= biosmap
[i
].addr
+
226 change_point
[chgidx
++]->pbios
= &biosmap
[i
];
231 /* sort change-point list by memory addresses (low -> high) */
233 while (still_changing
) {
235 for (i
= 1; i
< chg_nr
; i
++) {
236 unsigned long long curaddr
, lastaddr
;
237 unsigned long long curpbaddr
, lastpbaddr
;
239 curaddr
= change_point
[i
]->addr
;
240 lastaddr
= change_point
[i
- 1]->addr
;
241 curpbaddr
= change_point
[i
]->pbios
->addr
;
242 lastpbaddr
= change_point
[i
- 1]->pbios
->addr
;
245 * swap entries, when:
247 * curaddr > lastaddr or
248 * curaddr == lastaddr and curaddr == curpbaddr and
249 * lastaddr != lastpbaddr
251 if (curaddr
< lastaddr
||
252 (curaddr
== lastaddr
&& curaddr
== curpbaddr
&&
253 lastaddr
!= lastpbaddr
)) {
254 change_tmp
= change_point
[i
];
255 change_point
[i
] = change_point
[i
-1];
256 change_point
[i
-1] = change_tmp
;
262 /* create a new bios memory map, removing overlaps */
263 overlap_entries
= 0; /* number of entries in the overlap table */
264 new_bios_entry
= 0; /* index for creating new bios map entries */
265 last_type
= 0; /* start with undefined memory type */
266 last_addr
= 0; /* start with 0 as last starting address */
268 /* loop through change-points, determining affect on the new bios map */
269 for (chgidx
= 0; chgidx
< chg_nr
; chgidx
++) {
270 /* keep track of all overlapping bios entries */
271 if (change_point
[chgidx
]->addr
==
272 change_point
[chgidx
]->pbios
->addr
) {
274 * add map entry to overlap list (> 1 entry
275 * implies an overlap)
277 overlap_list
[overlap_entries
++] =
278 change_point
[chgidx
]->pbios
;
281 * remove entry from list (order independent,
284 for (i
= 0; i
< overlap_entries
; i
++) {
285 if (overlap_list
[i
] ==
286 change_point
[chgidx
]->pbios
)
288 overlap_list
[overlap_entries
-1];
293 * if there are overlapping entries, decide which
294 * "type" to use (larger value takes precedence --
295 * 1=usable, 2,3,4,4+=unusable)
298 for (i
= 0; i
< overlap_entries
; i
++)
299 if (overlap_list
[i
]->type
> current_type
)
300 current_type
= overlap_list
[i
]->type
;
302 * continue building up new bios map based on this
305 if (current_type
!= last_type
) {
306 if (last_type
!= 0) {
307 new_bios
[new_bios_entry
].size
=
308 change_point
[chgidx
]->addr
- last_addr
;
310 * move forward only if the new size
313 if (new_bios
[new_bios_entry
].size
!= 0)
315 * no more space left for new
318 if (++new_bios_entry
>= max_nr_map
)
321 if (current_type
!= 0) {
322 new_bios
[new_bios_entry
].addr
=
323 change_point
[chgidx
]->addr
;
324 new_bios
[new_bios_entry
].type
= current_type
;
325 last_addr
= change_point
[chgidx
]->addr
;
327 last_type
= current_type
;
330 /* retain count for new bios entries */
331 new_nr
= new_bios_entry
;
333 /* copy new bios mapping into original location */
334 memcpy(biosmap
, new_bios
, new_nr
* sizeof(struct e820entry
));
341 * Copy the BIOS e820 map into a safe place.
343 * Sanity-check it while we're at it..
345 * If we're lucky and live on a modern system, the setup code
346 * will have given us a memory map that we can use to properly
347 * set up memory. If we aren't, we'll fake a memory map.
349 int __init
copy_e820_map(struct e820entry
*biosmap
, int nr_map
)
351 /* Only one memory region (or negative)? Ignore it */
356 u64 start
= biosmap
->addr
;
357 u64 size
= biosmap
->size
;
358 u64 end
= start
+ size
;
359 u32 type
= biosmap
->type
;
361 /* Overflow in 64 bits? Ignore the memory map. */
365 add_memory_region(start
, size
, type
);
366 } while (biosmap
++, --nr_map
);
370 u64 __init
update_memory_range(u64 start
, u64 size
, unsigned old_type
,
374 u64 real_updated_size
= 0;
376 BUG_ON(old_type
== new_type
);
378 for (i
= 0; i
< e820
.nr_map
; i
++) {
379 struct e820entry
*ei
= &e820
.map
[i
];
380 u64 final_start
, final_end
;
381 if (ei
->type
!= old_type
)
383 /* totally covered? */
384 if (ei
->addr
>= start
&&
385 (ei
->addr
+ ei
->size
) <= (start
+ size
)) {
387 real_updated_size
+= ei
->size
;
390 /* partially covered */
391 final_start
= max(start
, ei
->addr
);
392 final_end
= min(start
+ size
, ei
->addr
+ ei
->size
);
393 if (final_start
>= final_end
)
395 add_memory_region(final_start
, final_end
- final_start
,
397 real_updated_size
+= final_end
- final_start
;
399 return real_updated_size
;
402 void __init
update_e820(void)
406 nr_map
= e820
.nr_map
;
407 if (sanitize_e820_map(e820
.map
, ARRAY_SIZE(e820
.map
), &nr_map
))
409 e820
.nr_map
= nr_map
;
410 printk(KERN_INFO
"modified physical RAM map:\n");
411 e820_print_map("modified");
415 * Search for the biggest gap in the low 32 bits of the e820
416 * memory space. We pass this space to PCI to assign MMIO resources
417 * for hotplug or unconfigured devices in.
418 * Hopefully the BIOS let enough space left.
420 __init
void e820_setup_gap(void)
422 unsigned long gapstart
, gapsize
, round
;
423 unsigned long long last
;
427 last
= 0x100000000ull
;
428 gapstart
= 0x10000000;
432 unsigned long long start
= e820
.map
[i
].addr
;
433 unsigned long long end
= start
+ e820
.map
[i
].size
;
436 * Since "last" is at most 4GB, we know we'll
437 * fit in 32 bits if this condition is true
440 unsigned long gap
= last
- end
;
454 gapstart
= (end_pfn
<< PAGE_SHIFT
) + 1024*1024;
455 printk(KERN_ERR
"PCI: Warning: Cannot find a gap in the 32bit "
457 KERN_ERR
"PCI: Unassigned devices with 32bit resource "
458 "registers may break!\n");
463 * See how much we want to round up: start off with
464 * rounding to the next 1MB area.
467 while ((gapsize
>> 4) > round
)
469 /* Fun with two's complement */
470 pci_mem_start
= (gapstart
+ round
) & -round
;
473 "Allocating PCI resources starting at %lx (gap: %lx:%lx)\n",
474 pci_mem_start
, gapstart
, gapsize
);