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Commit | Line | Data |
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7de828df KC |
1 | /* |
2 | * kaslr.c | |
3 | * | |
4 | * This contains the routines needed to generate a reasonable level of | |
5 | * entropy to choose a randomized kernel base address offset in support | |
6 | * of Kernel Address Space Layout Randomization (KASLR). Additionally | |
7 | * handles walking the physical memory maps (and tracking memory regions | |
8 | * to avoid) in order to select a physical memory location that can | |
9 | * contain the entire properly aligned running kernel image. | |
10 | * | |
11 | */ | |
8ab3820f | 12 | #include "misc.h" |
dc425a6e | 13 | #include "error.h" |
8ab3820f | 14 | |
5bfce5ef KC |
15 | #include <asm/msr.h> |
16 | #include <asm/archrandom.h> | |
82fa9637 | 17 | #include <asm/e820.h> |
5bfce5ef | 18 | |
a653f356 KC |
19 | #include <generated/compile.h> |
20 | #include <linux/module.h> | |
21 | #include <linux/uts.h> | |
22 | #include <linux/utsname.h> | |
23 | #include <generated/utsrelease.h> | |
a653f356 KC |
24 | |
25 | /* Simplified build-specific string for starting entropy. */ | |
327f7d72 | 26 | static const char build_str[] = UTS_RELEASE " (" LINUX_COMPILE_BY "@" |
a653f356 KC |
27 | LINUX_COMPILE_HOST ") (" LINUX_COMPILER ") " UTS_VERSION; |
28 | ||
5bfce5ef KC |
29 | #define I8254_PORT_CONTROL 0x43 |
30 | #define I8254_PORT_COUNTER0 0x40 | |
31 | #define I8254_CMD_READBACK 0xC0 | |
32 | #define I8254_SELECT_COUNTER0 0x02 | |
33 | #define I8254_STATUS_NOTREADY 0x40 | |
34 | static inline u16 i8254(void) | |
35 | { | |
36 | u16 status, timer; | |
37 | ||
38 | do { | |
39 | outb(I8254_PORT_CONTROL, | |
40 | I8254_CMD_READBACK | I8254_SELECT_COUNTER0); | |
41 | status = inb(I8254_PORT_COUNTER0); | |
42 | timer = inb(I8254_PORT_COUNTER0); | |
43 | timer |= inb(I8254_PORT_COUNTER0) << 8; | |
44 | } while (status & I8254_STATUS_NOTREADY); | |
45 | ||
46 | return timer; | |
47 | } | |
48 | ||
a653f356 KC |
49 | static unsigned long rotate_xor(unsigned long hash, const void *area, |
50 | size_t size) | |
51 | { | |
52 | size_t i; | |
53 | unsigned long *ptr = (unsigned long *)area; | |
54 | ||
55 | for (i = 0; i < size / sizeof(hash); i++) { | |
56 | /* Rotate by odd number of bits and XOR. */ | |
57 | hash = (hash << ((sizeof(hash) * 8) - 7)) | (hash >> 7); | |
58 | hash ^= ptr[i]; | |
59 | } | |
60 | ||
61 | return hash; | |
62 | } | |
63 | ||
64 | /* Attempt to create a simple but unpredictable starting entropy. */ | |
65 | static unsigned long get_random_boot(void) | |
66 | { | |
67 | unsigned long hash = 0; | |
68 | ||
69 | hash = rotate_xor(hash, build_str, sizeof(build_str)); | |
6655e0aa | 70 | hash = rotate_xor(hash, boot_params, sizeof(*boot_params)); |
a653f356 KC |
71 | |
72 | return hash; | |
73 | } | |
74 | ||
d2d3462f | 75 | static unsigned long get_random_long(const char *purpose) |
5bfce5ef | 76 | { |
e8236c4d PA |
77 | #ifdef CONFIG_X86_64 |
78 | const unsigned long mix_const = 0x5d6008cbf3848dd3UL; | |
79 | #else | |
80 | const unsigned long mix_const = 0x3f39e593UL; | |
81 | #endif | |
a653f356 KC |
82 | unsigned long raw, random = get_random_boot(); |
83 | bool use_i8254 = true; | |
84 | ||
d2d3462f KC |
85 | debug_putstr(purpose); |
86 | debug_putstr(" KASLR using"); | |
5bfce5ef KC |
87 | |
88 | if (has_cpuflag(X86_FEATURE_RDRAND)) { | |
a653f356 KC |
89 | debug_putstr(" RDRAND"); |
90 | if (rdrand_long(&raw)) { | |
91 | random ^= raw; | |
92 | use_i8254 = false; | |
93 | } | |
5bfce5ef KC |
94 | } |
95 | ||
96 | if (has_cpuflag(X86_FEATURE_TSC)) { | |
a653f356 | 97 | debug_putstr(" RDTSC"); |
4ea1636b | 98 | raw = rdtsc(); |
5bfce5ef | 99 | |
a653f356 KC |
100 | random ^= raw; |
101 | use_i8254 = false; | |
102 | } | |
5bfce5ef | 103 | |
a653f356 KC |
104 | if (use_i8254) { |
105 | debug_putstr(" i8254"); | |
106 | random ^= i8254(); | |
5bfce5ef KC |
107 | } |
108 | ||
e8236c4d PA |
109 | /* Circular multiply for better bit diffusion */ |
110 | asm("mul %3" | |
111 | : "=a" (random), "=d" (raw) | |
112 | : "a" (random), "rm" (mix_const)); | |
113 | random += raw; | |
114 | ||
a653f356 KC |
115 | debug_putstr("...\n"); |
116 | ||
5bfce5ef KC |
117 | return random; |
118 | } | |
8ab3820f | 119 | |
82fa9637 KC |
120 | struct mem_vector { |
121 | unsigned long start; | |
122 | unsigned long size; | |
123 | }; | |
124 | ||
ed09acde KC |
125 | enum mem_avoid_index { |
126 | MEM_AVOID_ZO_RANGE = 0, | |
127 | MEM_AVOID_INITRD, | |
128 | MEM_AVOID_CMDLINE, | |
129 | MEM_AVOID_BOOTPARAMS, | |
130 | MEM_AVOID_MAX, | |
131 | }; | |
132 | ||
e290e8c5 | 133 | static struct mem_vector mem_avoid[MEM_AVOID_MAX]; |
82fa9637 KC |
134 | |
135 | static bool mem_contains(struct mem_vector *region, struct mem_vector *item) | |
136 | { | |
137 | /* Item at least partially before region. */ | |
138 | if (item->start < region->start) | |
139 | return false; | |
140 | /* Item at least partially after region. */ | |
141 | if (item->start + item->size > region->start + region->size) | |
142 | return false; | |
143 | return true; | |
144 | } | |
145 | ||
146 | static bool mem_overlaps(struct mem_vector *one, struct mem_vector *two) | |
147 | { | |
148 | /* Item one is entirely before item two. */ | |
149 | if (one->start + one->size <= two->start) | |
150 | return false; | |
151 | /* Item one is entirely after item two. */ | |
152 | if (one->start >= two->start + two->size) | |
153 | return false; | |
154 | return true; | |
155 | } | |
156 | ||
9dc1969c | 157 | /* |
ed09acde KC |
158 | * In theory, KASLR can put the kernel anywhere in the range of [16M, 64T). |
159 | * The mem_avoid array is used to store the ranges that need to be avoided | |
160 | * when KASLR searches for an appropriate random address. We must avoid any | |
9dc1969c | 161 | * regions that are unsafe to overlap with during decompression, and other |
ed09acde KC |
162 | * things like the initrd, cmdline and boot_params. This comment seeks to |
163 | * explain mem_avoid as clearly as possible since incorrect mem_avoid | |
164 | * memory ranges lead to really hard to debug boot failures. | |
165 | * | |
166 | * The initrd, cmdline, and boot_params are trivial to identify for | |
cb18ef0d | 167 | * avoiding. They are MEM_AVOID_INITRD, MEM_AVOID_CMDLINE, and |
ed09acde KC |
168 | * MEM_AVOID_BOOTPARAMS respectively below. |
169 | * | |
170 | * What is not obvious how to avoid is the range of memory that is used | |
171 | * during decompression (MEM_AVOID_ZO_RANGE below). This range must cover | |
172 | * the compressed kernel (ZO) and its run space, which is used to extract | |
173 | * the uncompressed kernel (VO) and relocs. | |
174 | * | |
175 | * ZO's full run size sits against the end of the decompression buffer, so | |
176 | * we can calculate where text, data, bss, etc of ZO are positioned more | |
177 | * easily. | |
178 | * | |
179 | * For additional background, the decompression calculations can be found | |
180 | * in header.S, and the memory diagram is based on the one found in misc.c. | |
181 | * | |
182 | * The following conditions are already enforced by the image layouts and | |
183 | * associated code: | |
184 | * - input + input_size >= output + output_size | |
185 | * - kernel_total_size <= init_size | |
186 | * - kernel_total_size <= output_size (see Note below) | |
187 | * - output + init_size >= output + output_size | |
9dc1969c | 188 | * |
ed09acde KC |
189 | * (Note that kernel_total_size and output_size have no fundamental |
190 | * relationship, but output_size is passed to choose_random_location | |
191 | * as a maximum of the two. The diagram is showing a case where | |
192 | * kernel_total_size is larger than output_size, but this case is | |
193 | * handled by bumping output_size.) | |
9dc1969c | 194 | * |
ed09acde | 195 | * The above conditions can be illustrated by a diagram: |
9dc1969c | 196 | * |
ed09acde KC |
197 | * 0 output input input+input_size output+init_size |
198 | * | | | | | | |
199 | * | | | | | | |
200 | * |-----|--------|--------|--------------|-----------|--|-------------| | |
201 | * | | | | |
202 | * | | | | |
203 | * output+init_size-ZO_INIT_SIZE output+output_size output+kernel_total_size | |
9dc1969c | 204 | * |
ed09acde KC |
205 | * [output, output+init_size) is the entire memory range used for |
206 | * extracting the compressed image. | |
9dc1969c | 207 | * |
ed09acde KC |
208 | * [output, output+kernel_total_size) is the range needed for the |
209 | * uncompressed kernel (VO) and its run size (bss, brk, etc). | |
9dc1969c | 210 | * |
ed09acde KC |
211 | * [output, output+output_size) is VO plus relocs (i.e. the entire |
212 | * uncompressed payload contained by ZO). This is the area of the buffer | |
213 | * written to during decompression. | |
9dc1969c | 214 | * |
ed09acde KC |
215 | * [output+init_size-ZO_INIT_SIZE, output+init_size) is the worst-case |
216 | * range of the copied ZO and decompression code. (i.e. the range | |
217 | * covered backwards of size ZO_INIT_SIZE, starting from output+init_size.) | |
9dc1969c | 218 | * |
ed09acde KC |
219 | * [input, input+input_size) is the original copied compressed image (ZO) |
220 | * (i.e. it does not include its run size). This range must be avoided | |
221 | * because it contains the data used for decompression. | |
9dc1969c | 222 | * |
ed09acde KC |
223 | * [input+input_size, output+init_size) is [_text, _end) for ZO. This |
224 | * range includes ZO's heap and stack, and must be avoided since it | |
225 | * performs the decompression. | |
9dc1969c | 226 | * |
ed09acde KC |
227 | * Since the above two ranges need to be avoided and they are adjacent, |
228 | * they can be merged, resulting in: [input, output+init_size) which | |
229 | * becomes the MEM_AVOID_ZO_RANGE below. | |
9dc1969c | 230 | */ |
82fa9637 | 231 | static void mem_avoid_init(unsigned long input, unsigned long input_size, |
9dc1969c | 232 | unsigned long output) |
82fa9637 | 233 | { |
9dc1969c | 234 | unsigned long init_size = boot_params->hdr.init_size; |
82fa9637 KC |
235 | u64 initrd_start, initrd_size; |
236 | u64 cmd_line, cmd_line_size; | |
82fa9637 KC |
237 | char *ptr; |
238 | ||
239 | /* | |
240 | * Avoid the region that is unsafe to overlap during | |
9dc1969c | 241 | * decompression. |
82fa9637 | 242 | */ |
ed09acde KC |
243 | mem_avoid[MEM_AVOID_ZO_RANGE].start = input; |
244 | mem_avoid[MEM_AVOID_ZO_RANGE].size = (output + init_size) - input; | |
3a94707d KC |
245 | add_identity_map(mem_avoid[MEM_AVOID_ZO_RANGE].start, |
246 | mem_avoid[MEM_AVOID_ZO_RANGE].size); | |
82fa9637 KC |
247 | |
248 | /* Avoid initrd. */ | |
6655e0aa KC |
249 | initrd_start = (u64)boot_params->ext_ramdisk_image << 32; |
250 | initrd_start |= boot_params->hdr.ramdisk_image; | |
251 | initrd_size = (u64)boot_params->ext_ramdisk_size << 32; | |
252 | initrd_size |= boot_params->hdr.ramdisk_size; | |
ed09acde KC |
253 | mem_avoid[MEM_AVOID_INITRD].start = initrd_start; |
254 | mem_avoid[MEM_AVOID_INITRD].size = initrd_size; | |
3a94707d | 255 | /* No need to set mapping for initrd, it will be handled in VO. */ |
82fa9637 KC |
256 | |
257 | /* Avoid kernel command line. */ | |
6655e0aa KC |
258 | cmd_line = (u64)boot_params->ext_cmd_line_ptr << 32; |
259 | cmd_line |= boot_params->hdr.cmd_line_ptr; | |
82fa9637 KC |
260 | /* Calculate size of cmd_line. */ |
261 | ptr = (char *)(unsigned long)cmd_line; | |
262 | for (cmd_line_size = 0; ptr[cmd_line_size++]; ) | |
263 | ; | |
ed09acde KC |
264 | mem_avoid[MEM_AVOID_CMDLINE].start = cmd_line; |
265 | mem_avoid[MEM_AVOID_CMDLINE].size = cmd_line_size; | |
3a94707d KC |
266 | add_identity_map(mem_avoid[MEM_AVOID_CMDLINE].start, |
267 | mem_avoid[MEM_AVOID_CMDLINE].size); | |
82fa9637 | 268 | |
ed09acde KC |
269 | /* Avoid boot parameters. */ |
270 | mem_avoid[MEM_AVOID_BOOTPARAMS].start = (unsigned long)boot_params; | |
271 | mem_avoid[MEM_AVOID_BOOTPARAMS].size = sizeof(*boot_params); | |
3a94707d KC |
272 | add_identity_map(mem_avoid[MEM_AVOID_BOOTPARAMS].start, |
273 | mem_avoid[MEM_AVOID_BOOTPARAMS].size); | |
274 | ||
275 | /* We don't need to set a mapping for setup_data. */ | |
276 | ||
277 | #ifdef CONFIG_X86_VERBOSE_BOOTUP | |
278 | /* Make sure video RAM can be used. */ | |
279 | add_identity_map(0, PMD_SIZE); | |
280 | #endif | |
82fa9637 KC |
281 | } |
282 | ||
06486d6c KC |
283 | /* |
284 | * Does this memory vector overlap a known avoided area? If so, record the | |
285 | * overlap region with the lowest address. | |
286 | */ | |
287 | static bool mem_avoid_overlap(struct mem_vector *img, | |
288 | struct mem_vector *overlap) | |
82fa9637 KC |
289 | { |
290 | int i; | |
0cacbfbe | 291 | struct setup_data *ptr; |
06486d6c KC |
292 | unsigned long earliest = img->start + img->size; |
293 | bool is_overlapping = false; | |
82fa9637 KC |
294 | |
295 | for (i = 0; i < MEM_AVOID_MAX; i++) { | |
06486d6c KC |
296 | if (mem_overlaps(img, &mem_avoid[i]) && |
297 | mem_avoid[i].start < earliest) { | |
298 | *overlap = mem_avoid[i]; | |
299 | is_overlapping = true; | |
300 | } | |
82fa9637 KC |
301 | } |
302 | ||
0cacbfbe | 303 | /* Avoid all entries in the setup_data linked list. */ |
6655e0aa | 304 | ptr = (struct setup_data *)(unsigned long)boot_params->hdr.setup_data; |
0cacbfbe KC |
305 | while (ptr) { |
306 | struct mem_vector avoid; | |
307 | ||
20cc2888 | 308 | avoid.start = (unsigned long)ptr; |
0cacbfbe KC |
309 | avoid.size = sizeof(*ptr) + ptr->len; |
310 | ||
06486d6c KC |
311 | if (mem_overlaps(img, &avoid) && (avoid.start < earliest)) { |
312 | *overlap = avoid; | |
313 | is_overlapping = true; | |
314 | } | |
0cacbfbe KC |
315 | |
316 | ptr = (struct setup_data *)(unsigned long)ptr->next; | |
317 | } | |
318 | ||
06486d6c | 319 | return is_overlapping; |
82fa9637 KC |
320 | } |
321 | ||
e8581e3d | 322 | static unsigned long slots[KERNEL_IMAGE_SIZE / CONFIG_PHYSICAL_ALIGN]; |
c401cf15 BH |
323 | |
324 | struct slot_area { | |
325 | unsigned long addr; | |
326 | int num; | |
327 | }; | |
328 | ||
329 | #define MAX_SLOT_AREA 100 | |
330 | ||
331 | static struct slot_area slot_areas[MAX_SLOT_AREA]; | |
332 | ||
e290e8c5 | 333 | static unsigned long slot_max; |
82fa9637 | 334 | |
c401cf15 BH |
335 | static unsigned long slot_area_index; |
336 | ||
337 | static void store_slot_info(struct mem_vector *region, unsigned long image_size) | |
338 | { | |
339 | struct slot_area slot_area; | |
340 | ||
341 | if (slot_area_index == MAX_SLOT_AREA) | |
342 | return; | |
343 | ||
344 | slot_area.addr = region->start; | |
345 | slot_area.num = (region->size - image_size) / | |
346 | CONFIG_PHYSICAL_ALIGN + 1; | |
347 | ||
348 | if (slot_area.num > 0) { | |
349 | slot_areas[slot_area_index++] = slot_area; | |
350 | slot_max += slot_area.num; | |
351 | } | |
352 | } | |
353 | ||
82fa9637 KC |
354 | static void slots_append(unsigned long addr) |
355 | { | |
356 | /* Overflowing the slots list should be impossible. */ | |
e8581e3d | 357 | if (slot_max >= KERNEL_IMAGE_SIZE / CONFIG_PHYSICAL_ALIGN) |
82fa9637 KC |
358 | return; |
359 | ||
360 | slots[slot_max++] = addr; | |
361 | } | |
362 | ||
363 | static unsigned long slots_fetch_random(void) | |
364 | { | |
365 | /* Handle case of no slots stored. */ | |
366 | if (slot_max == 0) | |
367 | return 0; | |
368 | ||
d2d3462f | 369 | return slots[get_random_long("Physical") % slot_max]; |
82fa9637 KC |
370 | } |
371 | ||
372 | static void process_e820_entry(struct e820entry *entry, | |
373 | unsigned long minimum, | |
374 | unsigned long image_size) | |
375 | { | |
06486d6c | 376 | struct mem_vector region, img, overlap; |
82fa9637 KC |
377 | |
378 | /* Skip non-RAM entries. */ | |
379 | if (entry->type != E820_RAM) | |
380 | return; | |
381 | ||
382 | /* Ignore entries entirely above our maximum. */ | |
e8581e3d | 383 | if (entry->addr >= KERNEL_IMAGE_SIZE) |
82fa9637 KC |
384 | return; |
385 | ||
386 | /* Ignore entries entirely below our minimum. */ | |
387 | if (entry->addr + entry->size < minimum) | |
388 | return; | |
389 | ||
390 | region.start = entry->addr; | |
391 | region.size = entry->size; | |
392 | ||
393 | /* Potentially raise address to minimum location. */ | |
394 | if (region.start < minimum) | |
395 | region.start = minimum; | |
396 | ||
397 | /* Potentially raise address to meet alignment requirements. */ | |
398 | region.start = ALIGN(region.start, CONFIG_PHYSICAL_ALIGN); | |
399 | ||
400 | /* Did we raise the address above the bounds of this e820 region? */ | |
401 | if (region.start > entry->addr + entry->size) | |
402 | return; | |
403 | ||
404 | /* Reduce size by any delta from the original address. */ | |
405 | region.size -= region.start - entry->addr; | |
406 | ||
407 | /* Reduce maximum size to fit end of image within maximum limit. */ | |
e8581e3d BH |
408 | if (region.start + region.size > KERNEL_IMAGE_SIZE) |
409 | region.size = KERNEL_IMAGE_SIZE - region.start; | |
82fa9637 KC |
410 | |
411 | /* Walk each aligned slot and check for avoided areas. */ | |
412 | for (img.start = region.start, img.size = image_size ; | |
413 | mem_contains(®ion, &img) ; | |
414 | img.start += CONFIG_PHYSICAL_ALIGN) { | |
06486d6c | 415 | if (mem_avoid_overlap(&img, &overlap)) |
82fa9637 KC |
416 | continue; |
417 | slots_append(img.start); | |
418 | } | |
419 | } | |
420 | ||
071a7493 BH |
421 | static unsigned long find_random_phys_addr(unsigned long minimum, |
422 | unsigned long image_size) | |
82fa9637 KC |
423 | { |
424 | int i; | |
425 | unsigned long addr; | |
426 | ||
427 | /* Make sure minimum is aligned. */ | |
428 | minimum = ALIGN(minimum, CONFIG_PHYSICAL_ALIGN); | |
429 | ||
430 | /* Verify potential e820 positions, appending to slots list. */ | |
6655e0aa | 431 | for (i = 0; i < boot_params->e820_entries; i++) { |
071a7493 BH |
432 | process_e820_entry(&boot_params->e820_map[i], minimum, |
433 | image_size); | |
82fa9637 KC |
434 | } |
435 | ||
436 | return slots_fetch_random(); | |
437 | } | |
438 | ||
071a7493 BH |
439 | static unsigned long find_random_virt_addr(unsigned long minimum, |
440 | unsigned long image_size) | |
441 | { | |
442 | unsigned long slots, random_addr; | |
443 | ||
444 | /* Make sure minimum is aligned. */ | |
445 | minimum = ALIGN(minimum, CONFIG_PHYSICAL_ALIGN); | |
446 | /* Align image_size for easy slot calculations. */ | |
447 | image_size = ALIGN(image_size, CONFIG_PHYSICAL_ALIGN); | |
448 | ||
449 | /* | |
450 | * There are how many CONFIG_PHYSICAL_ALIGN-sized slots | |
451 | * that can hold image_size within the range of minimum to | |
452 | * KERNEL_IMAGE_SIZE? | |
453 | */ | |
454 | slots = (KERNEL_IMAGE_SIZE - minimum - image_size) / | |
455 | CONFIG_PHYSICAL_ALIGN + 1; | |
456 | ||
d2d3462f | 457 | random_addr = get_random_long("Virtual") % slots; |
071a7493 BH |
458 | |
459 | return random_addr * CONFIG_PHYSICAL_ALIGN + minimum; | |
460 | } | |
461 | ||
549f90db BP |
462 | /* |
463 | * Since this function examines addresses much more numerically, | |
464 | * it takes the input and output pointers as 'unsigned long'. | |
465 | */ | |
8391c73c BH |
466 | void choose_random_location(unsigned long input, |
467 | unsigned long input_size, | |
468 | unsigned long *output, | |
469 | unsigned long output_size, | |
470 | unsigned long *virt_addr) | |
8ab3820f | 471 | { |
9016875d | 472 | unsigned long random_addr; |
8ab3820f | 473 | |
8391c73c BH |
474 | /* By default, keep output position unchanged. */ |
475 | *virt_addr = *output; | |
476 | ||
8ab3820f | 477 | if (cmdline_find_option_bool("nokaslr")) { |
0f8ede1b | 478 | warn("KASLR disabled: 'nokaslr' on cmdline."); |
8391c73c | 479 | return; |
8ab3820f KC |
480 | } |
481 | ||
6655e0aa | 482 | boot_params->hdr.loadflags |= KASLR_FLAG; |
78cac48c | 483 | |
11fdf97a KC |
484 | /* Prepare to add new identity pagetables on demand. */ |
485 | initialize_identity_maps(); | |
486 | ||
82fa9637 | 487 | /* Record the various known unsafe memory ranges. */ |
8391c73c | 488 | mem_avoid_init(input, input_size, *output); |
82fa9637 KC |
489 | |
490 | /* Walk e820 and find a random address. */ | |
8391c73c | 491 | random_addr = find_random_phys_addr(*output, output_size); |
9016875d | 492 | if (!random_addr) { |
0f8ede1b | 493 | warn("KASLR disabled: could not find suitable E820 region!"); |
8391c73c BH |
494 | } else { |
495 | /* Update the new physical address location. */ | |
496 | if (*output != random_addr) { | |
497 | add_identity_map(random_addr, output_size); | |
498 | *output = random_addr; | |
499 | } | |
82fa9637 KC |
500 | } |
501 | ||
36a39ac9 | 502 | /* This actually loads the identity pagetable on x86_64. */ |
3a94707d | 503 | finalize_identity_maps(); |
8391c73c BH |
504 | |
505 | /* Pick random virtual address starting from LOAD_PHYSICAL_ADDR. */ | |
506 | if (IS_ENABLED(CONFIG_X86_64)) | |
507 | random_addr = find_random_virt_addr(LOAD_PHYSICAL_ADDR, output_size); | |
508 | *virt_addr = random_addr; | |
8ab3820f | 509 | } |