Commit | Line | Data |
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2965faa5 DY |
1 | /* |
2 | * kexec.c - kexec system call core code. | |
3 | * Copyright (C) 2002-2004 Eric Biederman <ebiederm@xmission.com> | |
4 | * | |
5 | * This source code is licensed under the GNU General Public License, | |
6 | * Version 2. See the file COPYING for more details. | |
7 | */ | |
8 | ||
de90a6bc | 9 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
2965faa5 DY |
10 | |
11 | #include <linux/capability.h> | |
12 | #include <linux/mm.h> | |
13 | #include <linux/file.h> | |
14 | #include <linux/slab.h> | |
15 | #include <linux/fs.h> | |
16 | #include <linux/kexec.h> | |
17 | #include <linux/mutex.h> | |
18 | #include <linux/list.h> | |
19 | #include <linux/highmem.h> | |
20 | #include <linux/syscalls.h> | |
21 | #include <linux/reboot.h> | |
22 | #include <linux/ioport.h> | |
23 | #include <linux/hardirq.h> | |
24 | #include <linux/elf.h> | |
25 | #include <linux/elfcore.h> | |
26 | #include <linux/utsname.h> | |
27 | #include <linux/numa.h> | |
28 | #include <linux/suspend.h> | |
29 | #include <linux/device.h> | |
30 | #include <linux/freezer.h> | |
31 | #include <linux/pm.h> | |
32 | #include <linux/cpu.h> | |
33 | #include <linux/uaccess.h> | |
34 | #include <linux/io.h> | |
35 | #include <linux/console.h> | |
36 | #include <linux/vmalloc.h> | |
37 | #include <linux/swap.h> | |
38 | #include <linux/syscore_ops.h> | |
39 | #include <linux/compiler.h> | |
40 | #include <linux/hugetlb.h> | |
c207aee4 | 41 | #include <linux/frame.h> |
2965faa5 DY |
42 | |
43 | #include <asm/page.h> | |
44 | #include <asm/sections.h> | |
45 | ||
46 | #include <crypto/hash.h> | |
47 | #include <crypto/sha.h> | |
48 | #include "kexec_internal.h" | |
49 | ||
50 | DEFINE_MUTEX(kexec_mutex); | |
51 | ||
52 | /* Per cpu memory for storing cpu states in case of system crash. */ | |
53 | note_buf_t __percpu *crash_notes; | |
54 | ||
2965faa5 DY |
55 | /* Flag to indicate we are going to kexec a new kernel */ |
56 | bool kexec_in_progress = false; | |
57 | ||
58 | ||
59 | /* Location of the reserved area for the crash kernel */ | |
60 | struct resource crashk_res = { | |
61 | .name = "Crash kernel", | |
62 | .start = 0, | |
63 | .end = 0, | |
1a085d07 TK |
64 | .flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM, |
65 | .desc = IORES_DESC_CRASH_KERNEL | |
2965faa5 DY |
66 | }; |
67 | struct resource crashk_low_res = { | |
68 | .name = "Crash kernel", | |
69 | .start = 0, | |
70 | .end = 0, | |
1a085d07 TK |
71 | .flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM, |
72 | .desc = IORES_DESC_CRASH_KERNEL | |
2965faa5 DY |
73 | }; |
74 | ||
75 | int kexec_should_crash(struct task_struct *p) | |
76 | { | |
77 | /* | |
78 | * If crash_kexec_post_notifiers is enabled, don't run | |
79 | * crash_kexec() here yet, which must be run after panic | |
80 | * notifiers in panic(). | |
81 | */ | |
82 | if (crash_kexec_post_notifiers) | |
83 | return 0; | |
84 | /* | |
85 | * There are 4 panic() calls in do_exit() path, each of which | |
86 | * corresponds to each of these 4 conditions. | |
87 | */ | |
88 | if (in_interrupt() || !p->pid || is_global_init(p) || panic_on_oops) | |
89 | return 1; | |
90 | return 0; | |
91 | } | |
92 | ||
21db79e8 PT |
93 | int kexec_crash_loaded(void) |
94 | { | |
95 | return !!kexec_crash_image; | |
96 | } | |
97 | EXPORT_SYMBOL_GPL(kexec_crash_loaded); | |
98 | ||
2965faa5 DY |
99 | /* |
100 | * When kexec transitions to the new kernel there is a one-to-one | |
101 | * mapping between physical and virtual addresses. On processors | |
102 | * where you can disable the MMU this is trivial, and easy. For | |
103 | * others it is still a simple predictable page table to setup. | |
104 | * | |
105 | * In that environment kexec copies the new kernel to its final | |
106 | * resting place. This means I can only support memory whose | |
107 | * physical address can fit in an unsigned long. In particular | |
108 | * addresses where (pfn << PAGE_SHIFT) > ULONG_MAX cannot be handled. | |
109 | * If the assembly stub has more restrictive requirements | |
110 | * KEXEC_SOURCE_MEMORY_LIMIT and KEXEC_DEST_MEMORY_LIMIT can be | |
111 | * defined more restrictively in <asm/kexec.h>. | |
112 | * | |
113 | * The code for the transition from the current kernel to the | |
114 | * the new kernel is placed in the control_code_buffer, whose size | |
115 | * is given by KEXEC_CONTROL_PAGE_SIZE. In the best case only a single | |
116 | * page of memory is necessary, but some architectures require more. | |
117 | * Because this memory must be identity mapped in the transition from | |
118 | * virtual to physical addresses it must live in the range | |
119 | * 0 - TASK_SIZE, as only the user space mappings are arbitrarily | |
120 | * modifiable. | |
121 | * | |
122 | * The assembly stub in the control code buffer is passed a linked list | |
123 | * of descriptor pages detailing the source pages of the new kernel, | |
124 | * and the destination addresses of those source pages. As this data | |
125 | * structure is not used in the context of the current OS, it must | |
126 | * be self-contained. | |
127 | * | |
128 | * The code has been made to work with highmem pages and will use a | |
129 | * destination page in its final resting place (if it happens | |
130 | * to allocate it). The end product of this is that most of the | |
131 | * physical address space, and most of RAM can be used. | |
132 | * | |
133 | * Future directions include: | |
134 | * - allocating a page table with the control code buffer identity | |
135 | * mapped, to simplify machine_kexec and make kexec_on_panic more | |
136 | * reliable. | |
137 | */ | |
138 | ||
139 | /* | |
140 | * KIMAGE_NO_DEST is an impossible destination address..., for | |
141 | * allocating pages whose destination address we do not care about. | |
142 | */ | |
143 | #define KIMAGE_NO_DEST (-1UL) | |
1730f146 | 144 | #define PAGE_COUNT(x) (((x) + PAGE_SIZE - 1) >> PAGE_SHIFT) |
2965faa5 DY |
145 | |
146 | static struct page *kimage_alloc_page(struct kimage *image, | |
147 | gfp_t gfp_mask, | |
148 | unsigned long dest); | |
149 | ||
150 | int sanity_check_segment_list(struct kimage *image) | |
151 | { | |
4caf9615 | 152 | int i; |
2965faa5 | 153 | unsigned long nr_segments = image->nr_segments; |
1730f146 | 154 | unsigned long total_pages = 0; |
2965faa5 DY |
155 | |
156 | /* | |
157 | * Verify we have good destination addresses. The caller is | |
158 | * responsible for making certain we don't attempt to load | |
159 | * the new image into invalid or reserved areas of RAM. This | |
160 | * just verifies it is an address we can use. | |
161 | * | |
162 | * Since the kernel does everything in page size chunks ensure | |
163 | * the destination addresses are page aligned. Too many | |
164 | * special cases crop of when we don't do this. The most | |
165 | * insidious is getting overlapping destination addresses | |
166 | * simply because addresses are changed to page size | |
167 | * granularity. | |
168 | */ | |
2965faa5 DY |
169 | for (i = 0; i < nr_segments; i++) { |
170 | unsigned long mstart, mend; | |
171 | ||
172 | mstart = image->segment[i].mem; | |
173 | mend = mstart + image->segment[i].memsz; | |
465d3777 RK |
174 | if (mstart > mend) |
175 | return -EADDRNOTAVAIL; | |
2965faa5 | 176 | if ((mstart & ~PAGE_MASK) || (mend & ~PAGE_MASK)) |
4caf9615 | 177 | return -EADDRNOTAVAIL; |
2965faa5 | 178 | if (mend >= KEXEC_DESTINATION_MEMORY_LIMIT) |
4caf9615 | 179 | return -EADDRNOTAVAIL; |
2965faa5 DY |
180 | } |
181 | ||
182 | /* Verify our destination addresses do not overlap. | |
183 | * If we alloed overlapping destination addresses | |
184 | * through very weird things can happen with no | |
185 | * easy explanation as one segment stops on another. | |
186 | */ | |
2965faa5 DY |
187 | for (i = 0; i < nr_segments; i++) { |
188 | unsigned long mstart, mend; | |
189 | unsigned long j; | |
190 | ||
191 | mstart = image->segment[i].mem; | |
192 | mend = mstart + image->segment[i].memsz; | |
193 | for (j = 0; j < i; j++) { | |
194 | unsigned long pstart, pend; | |
195 | ||
196 | pstart = image->segment[j].mem; | |
197 | pend = pstart + image->segment[j].memsz; | |
198 | /* Do the segments overlap ? */ | |
199 | if ((mend > pstart) && (mstart < pend)) | |
4caf9615 | 200 | return -EINVAL; |
2965faa5 DY |
201 | } |
202 | } | |
203 | ||
204 | /* Ensure our buffer sizes are strictly less than | |
205 | * our memory sizes. This should always be the case, | |
206 | * and it is easier to check up front than to be surprised | |
207 | * later on. | |
208 | */ | |
2965faa5 DY |
209 | for (i = 0; i < nr_segments; i++) { |
210 | if (image->segment[i].bufsz > image->segment[i].memsz) | |
4caf9615 | 211 | return -EINVAL; |
2965faa5 DY |
212 | } |
213 | ||
1730f146 | 214 | /* |
215 | * Verify that no more than half of memory will be consumed. If the | |
216 | * request from userspace is too large, a large amount of time will be | |
217 | * wasted allocating pages, which can cause a soft lockup. | |
218 | */ | |
219 | for (i = 0; i < nr_segments; i++) { | |
220 | if (PAGE_COUNT(image->segment[i].memsz) > totalram_pages / 2) | |
221 | return -EINVAL; | |
222 | ||
223 | total_pages += PAGE_COUNT(image->segment[i].memsz); | |
224 | } | |
225 | ||
226 | if (total_pages > totalram_pages / 2) | |
227 | return -EINVAL; | |
228 | ||
2965faa5 DY |
229 | /* |
230 | * Verify we have good destination addresses. Normally | |
231 | * the caller is responsible for making certain we don't | |
232 | * attempt to load the new image into invalid or reserved | |
233 | * areas of RAM. But crash kernels are preloaded into a | |
234 | * reserved area of ram. We must ensure the addresses | |
235 | * are in the reserved area otherwise preloading the | |
236 | * kernel could corrupt things. | |
237 | */ | |
238 | ||
239 | if (image->type == KEXEC_TYPE_CRASH) { | |
2965faa5 DY |
240 | for (i = 0; i < nr_segments; i++) { |
241 | unsigned long mstart, mend; | |
242 | ||
243 | mstart = image->segment[i].mem; | |
244 | mend = mstart + image->segment[i].memsz - 1; | |
245 | /* Ensure we are within the crash kernel limits */ | |
43546d86 RK |
246 | if ((mstart < phys_to_boot_phys(crashk_res.start)) || |
247 | (mend > phys_to_boot_phys(crashk_res.end))) | |
4caf9615 | 248 | return -EADDRNOTAVAIL; |
2965faa5 DY |
249 | } |
250 | } | |
251 | ||
252 | return 0; | |
253 | } | |
254 | ||
255 | struct kimage *do_kimage_alloc_init(void) | |
256 | { | |
257 | struct kimage *image; | |
258 | ||
259 | /* Allocate a controlling structure */ | |
260 | image = kzalloc(sizeof(*image), GFP_KERNEL); | |
261 | if (!image) | |
262 | return NULL; | |
263 | ||
264 | image->head = 0; | |
265 | image->entry = &image->head; | |
266 | image->last_entry = &image->head; | |
267 | image->control_page = ~0; /* By default this does not apply */ | |
268 | image->type = KEXEC_TYPE_DEFAULT; | |
269 | ||
270 | /* Initialize the list of control pages */ | |
271 | INIT_LIST_HEAD(&image->control_pages); | |
272 | ||
273 | /* Initialize the list of destination pages */ | |
274 | INIT_LIST_HEAD(&image->dest_pages); | |
275 | ||
276 | /* Initialize the list of unusable pages */ | |
277 | INIT_LIST_HEAD(&image->unusable_pages); | |
278 | ||
279 | return image; | |
280 | } | |
281 | ||
282 | int kimage_is_destination_range(struct kimage *image, | |
283 | unsigned long start, | |
284 | unsigned long end) | |
285 | { | |
286 | unsigned long i; | |
287 | ||
288 | for (i = 0; i < image->nr_segments; i++) { | |
289 | unsigned long mstart, mend; | |
290 | ||
291 | mstart = image->segment[i].mem; | |
292 | mend = mstart + image->segment[i].memsz; | |
293 | if ((end > mstart) && (start < mend)) | |
294 | return 1; | |
295 | } | |
296 | ||
297 | return 0; | |
298 | } | |
299 | ||
300 | static struct page *kimage_alloc_pages(gfp_t gfp_mask, unsigned int order) | |
301 | { | |
302 | struct page *pages; | |
303 | ||
304 | pages = alloc_pages(gfp_mask, order); | |
305 | if (pages) { | |
306 | unsigned int count, i; | |
307 | ||
308 | pages->mapping = NULL; | |
309 | set_page_private(pages, order); | |
310 | count = 1 << order; | |
311 | for (i = 0; i < count; i++) | |
312 | SetPageReserved(pages + i); | |
313 | } | |
314 | ||
315 | return pages; | |
316 | } | |
317 | ||
318 | static void kimage_free_pages(struct page *page) | |
319 | { | |
320 | unsigned int order, count, i; | |
321 | ||
322 | order = page_private(page); | |
323 | count = 1 << order; | |
324 | for (i = 0; i < count; i++) | |
325 | ClearPageReserved(page + i); | |
326 | __free_pages(page, order); | |
327 | } | |
328 | ||
329 | void kimage_free_page_list(struct list_head *list) | |
330 | { | |
2b24692b | 331 | struct page *page, *next; |
2965faa5 | 332 | |
2b24692b | 333 | list_for_each_entry_safe(page, next, list, lru) { |
2965faa5 DY |
334 | list_del(&page->lru); |
335 | kimage_free_pages(page); | |
336 | } | |
337 | } | |
338 | ||
339 | static struct page *kimage_alloc_normal_control_pages(struct kimage *image, | |
340 | unsigned int order) | |
341 | { | |
342 | /* Control pages are special, they are the intermediaries | |
343 | * that are needed while we copy the rest of the pages | |
344 | * to their final resting place. As such they must | |
345 | * not conflict with either the destination addresses | |
346 | * or memory the kernel is already using. | |
347 | * | |
348 | * The only case where we really need more than one of | |
349 | * these are for architectures where we cannot disable | |
350 | * the MMU and must instead generate an identity mapped | |
351 | * page table for all of the memory. | |
352 | * | |
353 | * At worst this runs in O(N) of the image size. | |
354 | */ | |
355 | struct list_head extra_pages; | |
356 | struct page *pages; | |
357 | unsigned int count; | |
358 | ||
359 | count = 1 << order; | |
360 | INIT_LIST_HEAD(&extra_pages); | |
361 | ||
362 | /* Loop while I can allocate a page and the page allocated | |
363 | * is a destination page. | |
364 | */ | |
365 | do { | |
366 | unsigned long pfn, epfn, addr, eaddr; | |
367 | ||
368 | pages = kimage_alloc_pages(KEXEC_CONTROL_MEMORY_GFP, order); | |
369 | if (!pages) | |
370 | break; | |
43546d86 | 371 | pfn = page_to_boot_pfn(pages); |
2965faa5 DY |
372 | epfn = pfn + count; |
373 | addr = pfn << PAGE_SHIFT; | |
374 | eaddr = epfn << PAGE_SHIFT; | |
375 | if ((epfn >= (KEXEC_CONTROL_MEMORY_LIMIT >> PAGE_SHIFT)) || | |
376 | kimage_is_destination_range(image, addr, eaddr)) { | |
377 | list_add(&pages->lru, &extra_pages); | |
378 | pages = NULL; | |
379 | } | |
380 | } while (!pages); | |
381 | ||
382 | if (pages) { | |
383 | /* Remember the allocated page... */ | |
384 | list_add(&pages->lru, &image->control_pages); | |
385 | ||
386 | /* Because the page is already in it's destination | |
387 | * location we will never allocate another page at | |
388 | * that address. Therefore kimage_alloc_pages | |
389 | * will not return it (again) and we don't need | |
390 | * to give it an entry in image->segment[]. | |
391 | */ | |
392 | } | |
393 | /* Deal with the destination pages I have inadvertently allocated. | |
394 | * | |
395 | * Ideally I would convert multi-page allocations into single | |
396 | * page allocations, and add everything to image->dest_pages. | |
397 | * | |
398 | * For now it is simpler to just free the pages. | |
399 | */ | |
400 | kimage_free_page_list(&extra_pages); | |
401 | ||
402 | return pages; | |
403 | } | |
404 | ||
405 | static struct page *kimage_alloc_crash_control_pages(struct kimage *image, | |
406 | unsigned int order) | |
407 | { | |
408 | /* Control pages are special, they are the intermediaries | |
409 | * that are needed while we copy the rest of the pages | |
410 | * to their final resting place. As such they must | |
411 | * not conflict with either the destination addresses | |
412 | * or memory the kernel is already using. | |
413 | * | |
414 | * Control pages are also the only pags we must allocate | |
415 | * when loading a crash kernel. All of the other pages | |
416 | * are specified by the segments and we just memcpy | |
417 | * into them directly. | |
418 | * | |
419 | * The only case where we really need more than one of | |
420 | * these are for architectures where we cannot disable | |
421 | * the MMU and must instead generate an identity mapped | |
422 | * page table for all of the memory. | |
423 | * | |
424 | * Given the low demand this implements a very simple | |
425 | * allocator that finds the first hole of the appropriate | |
426 | * size in the reserved memory region, and allocates all | |
427 | * of the memory up to and including the hole. | |
428 | */ | |
429 | unsigned long hole_start, hole_end, size; | |
430 | struct page *pages; | |
431 | ||
432 | pages = NULL; | |
433 | size = (1 << order) << PAGE_SHIFT; | |
434 | hole_start = (image->control_page + (size - 1)) & ~(size - 1); | |
435 | hole_end = hole_start + size - 1; | |
436 | while (hole_end <= crashk_res.end) { | |
437 | unsigned long i; | |
438 | ||
8e53c073 | 439 | cond_resched(); |
440 | ||
2965faa5 DY |
441 | if (hole_end > KEXEC_CRASH_CONTROL_MEMORY_LIMIT) |
442 | break; | |
443 | /* See if I overlap any of the segments */ | |
444 | for (i = 0; i < image->nr_segments; i++) { | |
445 | unsigned long mstart, mend; | |
446 | ||
447 | mstart = image->segment[i].mem; | |
448 | mend = mstart + image->segment[i].memsz - 1; | |
449 | if ((hole_end >= mstart) && (hole_start <= mend)) { | |
450 | /* Advance the hole to the end of the segment */ | |
451 | hole_start = (mend + (size - 1)) & ~(size - 1); | |
452 | hole_end = hole_start + size - 1; | |
453 | break; | |
454 | } | |
455 | } | |
456 | /* If I don't overlap any segments I have found my hole! */ | |
457 | if (i == image->nr_segments) { | |
458 | pages = pfn_to_page(hole_start >> PAGE_SHIFT); | |
04e9949b | 459 | image->control_page = hole_end; |
2965faa5 DY |
460 | break; |
461 | } | |
462 | } | |
2965faa5 DY |
463 | |
464 | return pages; | |
465 | } | |
466 | ||
467 | ||
468 | struct page *kimage_alloc_control_pages(struct kimage *image, | |
469 | unsigned int order) | |
470 | { | |
471 | struct page *pages = NULL; | |
472 | ||
473 | switch (image->type) { | |
474 | case KEXEC_TYPE_DEFAULT: | |
475 | pages = kimage_alloc_normal_control_pages(image, order); | |
476 | break; | |
477 | case KEXEC_TYPE_CRASH: | |
478 | pages = kimage_alloc_crash_control_pages(image, order); | |
479 | break; | |
480 | } | |
481 | ||
482 | return pages; | |
483 | } | |
484 | ||
1229384f XP |
485 | int kimage_crash_copy_vmcoreinfo(struct kimage *image) |
486 | { | |
487 | struct page *vmcoreinfo_page; | |
488 | void *safecopy; | |
489 | ||
490 | if (image->type != KEXEC_TYPE_CRASH) | |
491 | return 0; | |
492 | ||
493 | /* | |
494 | * For kdump, allocate one vmcoreinfo safe copy from the | |
495 | * crash memory. as we have arch_kexec_protect_crashkres() | |
496 | * after kexec syscall, we naturally protect it from write | |
497 | * (even read) access under kernel direct mapping. But on | |
498 | * the other hand, we still need to operate it when crash | |
499 | * happens to generate vmcoreinfo note, hereby we rely on | |
500 | * vmap for this purpose. | |
501 | */ | |
502 | vmcoreinfo_page = kimage_alloc_control_pages(image, 0); | |
503 | if (!vmcoreinfo_page) { | |
504 | pr_warn("Could not allocate vmcoreinfo buffer\n"); | |
505 | return -ENOMEM; | |
506 | } | |
507 | safecopy = vmap(&vmcoreinfo_page, 1, VM_MAP, PAGE_KERNEL); | |
508 | if (!safecopy) { | |
509 | pr_warn("Could not vmap vmcoreinfo buffer\n"); | |
510 | return -ENOMEM; | |
511 | } | |
512 | ||
513 | image->vmcoreinfo_data_copy = safecopy; | |
514 | crash_update_vmcoreinfo_safecopy(safecopy); | |
515 | ||
516 | return 0; | |
517 | } | |
518 | ||
2965faa5 DY |
519 | static int kimage_add_entry(struct kimage *image, kimage_entry_t entry) |
520 | { | |
521 | if (*image->entry != 0) | |
522 | image->entry++; | |
523 | ||
524 | if (image->entry == image->last_entry) { | |
525 | kimage_entry_t *ind_page; | |
526 | struct page *page; | |
527 | ||
528 | page = kimage_alloc_page(image, GFP_KERNEL, KIMAGE_NO_DEST); | |
529 | if (!page) | |
530 | return -ENOMEM; | |
531 | ||
532 | ind_page = page_address(page); | |
43546d86 | 533 | *image->entry = virt_to_boot_phys(ind_page) | IND_INDIRECTION; |
2965faa5 DY |
534 | image->entry = ind_page; |
535 | image->last_entry = ind_page + | |
536 | ((PAGE_SIZE/sizeof(kimage_entry_t)) - 1); | |
537 | } | |
538 | *image->entry = entry; | |
539 | image->entry++; | |
540 | *image->entry = 0; | |
541 | ||
542 | return 0; | |
543 | } | |
544 | ||
545 | static int kimage_set_destination(struct kimage *image, | |
546 | unsigned long destination) | |
547 | { | |
548 | int result; | |
549 | ||
550 | destination &= PAGE_MASK; | |
551 | result = kimage_add_entry(image, destination | IND_DESTINATION); | |
552 | ||
553 | return result; | |
554 | } | |
555 | ||
556 | ||
557 | static int kimage_add_page(struct kimage *image, unsigned long page) | |
558 | { | |
559 | int result; | |
560 | ||
561 | page &= PAGE_MASK; | |
562 | result = kimage_add_entry(image, page | IND_SOURCE); | |
563 | ||
564 | return result; | |
565 | } | |
566 | ||
567 | ||
568 | static void kimage_free_extra_pages(struct kimage *image) | |
569 | { | |
570 | /* Walk through and free any extra destination pages I may have */ | |
571 | kimage_free_page_list(&image->dest_pages); | |
572 | ||
573 | /* Walk through and free any unusable pages I have cached */ | |
574 | kimage_free_page_list(&image->unusable_pages); | |
575 | ||
576 | } | |
577 | void kimage_terminate(struct kimage *image) | |
578 | { | |
579 | if (*image->entry != 0) | |
580 | image->entry++; | |
581 | ||
582 | *image->entry = IND_DONE; | |
583 | } | |
584 | ||
585 | #define for_each_kimage_entry(image, ptr, entry) \ | |
586 | for (ptr = &image->head; (entry = *ptr) && !(entry & IND_DONE); \ | |
587 | ptr = (entry & IND_INDIRECTION) ? \ | |
43546d86 | 588 | boot_phys_to_virt((entry & PAGE_MASK)) : ptr + 1) |
2965faa5 DY |
589 | |
590 | static void kimage_free_entry(kimage_entry_t entry) | |
591 | { | |
592 | struct page *page; | |
593 | ||
43546d86 | 594 | page = boot_pfn_to_page(entry >> PAGE_SHIFT); |
2965faa5 DY |
595 | kimage_free_pages(page); |
596 | } | |
597 | ||
598 | void kimage_free(struct kimage *image) | |
599 | { | |
600 | kimage_entry_t *ptr, entry; | |
601 | kimage_entry_t ind = 0; | |
602 | ||
603 | if (!image) | |
604 | return; | |
605 | ||
1229384f XP |
606 | if (image->vmcoreinfo_data_copy) { |
607 | crash_update_vmcoreinfo_safecopy(NULL); | |
608 | vunmap(image->vmcoreinfo_data_copy); | |
609 | } | |
610 | ||
2965faa5 DY |
611 | kimage_free_extra_pages(image); |
612 | for_each_kimage_entry(image, ptr, entry) { | |
613 | if (entry & IND_INDIRECTION) { | |
614 | /* Free the previous indirection page */ | |
615 | if (ind & IND_INDIRECTION) | |
616 | kimage_free_entry(ind); | |
617 | /* Save this indirection page until we are | |
618 | * done with it. | |
619 | */ | |
620 | ind = entry; | |
621 | } else if (entry & IND_SOURCE) | |
622 | kimage_free_entry(entry); | |
623 | } | |
624 | /* Free the final indirection page */ | |
625 | if (ind & IND_INDIRECTION) | |
626 | kimage_free_entry(ind); | |
627 | ||
628 | /* Handle any machine specific cleanup */ | |
629 | machine_kexec_cleanup(image); | |
630 | ||
631 | /* Free the kexec control pages... */ | |
632 | kimage_free_page_list(&image->control_pages); | |
633 | ||
634 | /* | |
635 | * Free up any temporary buffers allocated. This might hit if | |
636 | * error occurred much later after buffer allocation. | |
637 | */ | |
638 | if (image->file_mode) | |
639 | kimage_file_post_load_cleanup(image); | |
640 | ||
641 | kfree(image); | |
642 | } | |
643 | ||
644 | static kimage_entry_t *kimage_dst_used(struct kimage *image, | |
645 | unsigned long page) | |
646 | { | |
647 | kimage_entry_t *ptr, entry; | |
648 | unsigned long destination = 0; | |
649 | ||
650 | for_each_kimage_entry(image, ptr, entry) { | |
651 | if (entry & IND_DESTINATION) | |
652 | destination = entry & PAGE_MASK; | |
653 | else if (entry & IND_SOURCE) { | |
654 | if (page == destination) | |
655 | return ptr; | |
656 | destination += PAGE_SIZE; | |
657 | } | |
658 | } | |
659 | ||
660 | return NULL; | |
661 | } | |
662 | ||
663 | static struct page *kimage_alloc_page(struct kimage *image, | |
664 | gfp_t gfp_mask, | |
665 | unsigned long destination) | |
666 | { | |
667 | /* | |
668 | * Here we implement safeguards to ensure that a source page | |
669 | * is not copied to its destination page before the data on | |
670 | * the destination page is no longer useful. | |
671 | * | |
672 | * To do this we maintain the invariant that a source page is | |
673 | * either its own destination page, or it is not a | |
674 | * destination page at all. | |
675 | * | |
676 | * That is slightly stronger than required, but the proof | |
677 | * that no problems will not occur is trivial, and the | |
678 | * implementation is simply to verify. | |
679 | * | |
680 | * When allocating all pages normally this algorithm will run | |
681 | * in O(N) time, but in the worst case it will run in O(N^2) | |
682 | * time. If the runtime is a problem the data structures can | |
683 | * be fixed. | |
684 | */ | |
685 | struct page *page; | |
686 | unsigned long addr; | |
687 | ||
688 | /* | |
689 | * Walk through the list of destination pages, and see if I | |
690 | * have a match. | |
691 | */ | |
692 | list_for_each_entry(page, &image->dest_pages, lru) { | |
43546d86 | 693 | addr = page_to_boot_pfn(page) << PAGE_SHIFT; |
2965faa5 DY |
694 | if (addr == destination) { |
695 | list_del(&page->lru); | |
696 | return page; | |
697 | } | |
698 | } | |
699 | page = NULL; | |
700 | while (1) { | |
701 | kimage_entry_t *old; | |
702 | ||
703 | /* Allocate a page, if we run out of memory give up */ | |
704 | page = kimage_alloc_pages(gfp_mask, 0); | |
705 | if (!page) | |
706 | return NULL; | |
707 | /* If the page cannot be used file it away */ | |
43546d86 | 708 | if (page_to_boot_pfn(page) > |
2965faa5 DY |
709 | (KEXEC_SOURCE_MEMORY_LIMIT >> PAGE_SHIFT)) { |
710 | list_add(&page->lru, &image->unusable_pages); | |
711 | continue; | |
712 | } | |
43546d86 | 713 | addr = page_to_boot_pfn(page) << PAGE_SHIFT; |
2965faa5 DY |
714 | |
715 | /* If it is the destination page we want use it */ | |
716 | if (addr == destination) | |
717 | break; | |
718 | ||
719 | /* If the page is not a destination page use it */ | |
720 | if (!kimage_is_destination_range(image, addr, | |
721 | addr + PAGE_SIZE)) | |
722 | break; | |
723 | ||
724 | /* | |
725 | * I know that the page is someones destination page. | |
726 | * See if there is already a source page for this | |
727 | * destination page. And if so swap the source pages. | |
728 | */ | |
729 | old = kimage_dst_used(image, addr); | |
730 | if (old) { | |
731 | /* If so move it */ | |
732 | unsigned long old_addr; | |
733 | struct page *old_page; | |
734 | ||
735 | old_addr = *old & PAGE_MASK; | |
43546d86 | 736 | old_page = boot_pfn_to_page(old_addr >> PAGE_SHIFT); |
2965faa5 DY |
737 | copy_highpage(page, old_page); |
738 | *old = addr | (*old & ~PAGE_MASK); | |
739 | ||
740 | /* The old page I have found cannot be a | |
741 | * destination page, so return it if it's | |
742 | * gfp_flags honor the ones passed in. | |
743 | */ | |
744 | if (!(gfp_mask & __GFP_HIGHMEM) && | |
745 | PageHighMem(old_page)) { | |
746 | kimage_free_pages(old_page); | |
747 | continue; | |
748 | } | |
749 | addr = old_addr; | |
750 | page = old_page; | |
751 | break; | |
752 | } | |
753 | /* Place the page on the destination list, to be used later */ | |
754 | list_add(&page->lru, &image->dest_pages); | |
755 | } | |
756 | ||
757 | return page; | |
758 | } | |
759 | ||
760 | static int kimage_load_normal_segment(struct kimage *image, | |
761 | struct kexec_segment *segment) | |
762 | { | |
763 | unsigned long maddr; | |
764 | size_t ubytes, mbytes; | |
765 | int result; | |
766 | unsigned char __user *buf = NULL; | |
767 | unsigned char *kbuf = NULL; | |
768 | ||
769 | result = 0; | |
770 | if (image->file_mode) | |
771 | kbuf = segment->kbuf; | |
772 | else | |
773 | buf = segment->buf; | |
774 | ubytes = segment->bufsz; | |
775 | mbytes = segment->memsz; | |
776 | maddr = segment->mem; | |
777 | ||
778 | result = kimage_set_destination(image, maddr); | |
779 | if (result < 0) | |
780 | goto out; | |
781 | ||
782 | while (mbytes) { | |
783 | struct page *page; | |
784 | char *ptr; | |
785 | size_t uchunk, mchunk; | |
786 | ||
787 | page = kimage_alloc_page(image, GFP_HIGHUSER, maddr); | |
788 | if (!page) { | |
789 | result = -ENOMEM; | |
790 | goto out; | |
791 | } | |
43546d86 | 792 | result = kimage_add_page(image, page_to_boot_pfn(page) |
2965faa5 DY |
793 | << PAGE_SHIFT); |
794 | if (result < 0) | |
795 | goto out; | |
796 | ||
797 | ptr = kmap(page); | |
798 | /* Start with a clear page */ | |
799 | clear_page(ptr); | |
800 | ptr += maddr & ~PAGE_MASK; | |
801 | mchunk = min_t(size_t, mbytes, | |
802 | PAGE_SIZE - (maddr & ~PAGE_MASK)); | |
803 | uchunk = min(ubytes, mchunk); | |
804 | ||
805 | /* For file based kexec, source pages are in kernel memory */ | |
806 | if (image->file_mode) | |
807 | memcpy(ptr, kbuf, uchunk); | |
808 | else | |
809 | result = copy_from_user(ptr, buf, uchunk); | |
810 | kunmap(page); | |
811 | if (result) { | |
812 | result = -EFAULT; | |
813 | goto out; | |
814 | } | |
815 | ubytes -= uchunk; | |
816 | maddr += mchunk; | |
817 | if (image->file_mode) | |
818 | kbuf += mchunk; | |
819 | else | |
820 | buf += mchunk; | |
821 | mbytes -= mchunk; | |
822 | } | |
823 | out: | |
824 | return result; | |
825 | } | |
826 | ||
827 | static int kimage_load_crash_segment(struct kimage *image, | |
828 | struct kexec_segment *segment) | |
829 | { | |
830 | /* For crash dumps kernels we simply copy the data from | |
831 | * user space to it's destination. | |
832 | * We do things a page at a time for the sake of kmap. | |
833 | */ | |
834 | unsigned long maddr; | |
835 | size_t ubytes, mbytes; | |
836 | int result; | |
837 | unsigned char __user *buf = NULL; | |
838 | unsigned char *kbuf = NULL; | |
839 | ||
840 | result = 0; | |
841 | if (image->file_mode) | |
842 | kbuf = segment->kbuf; | |
843 | else | |
844 | buf = segment->buf; | |
845 | ubytes = segment->bufsz; | |
846 | mbytes = segment->memsz; | |
847 | maddr = segment->mem; | |
848 | while (mbytes) { | |
849 | struct page *page; | |
850 | char *ptr; | |
851 | size_t uchunk, mchunk; | |
852 | ||
43546d86 | 853 | page = boot_pfn_to_page(maddr >> PAGE_SHIFT); |
2965faa5 DY |
854 | if (!page) { |
855 | result = -ENOMEM; | |
856 | goto out; | |
857 | } | |
858 | ptr = kmap(page); | |
859 | ptr += maddr & ~PAGE_MASK; | |
860 | mchunk = min_t(size_t, mbytes, | |
861 | PAGE_SIZE - (maddr & ~PAGE_MASK)); | |
862 | uchunk = min(ubytes, mchunk); | |
863 | if (mchunk > uchunk) { | |
864 | /* Zero the trailing part of the page */ | |
865 | memset(ptr + uchunk, 0, mchunk - uchunk); | |
866 | } | |
867 | ||
868 | /* For file based kexec, source pages are in kernel memory */ | |
869 | if (image->file_mode) | |
870 | memcpy(ptr, kbuf, uchunk); | |
871 | else | |
872 | result = copy_from_user(ptr, buf, uchunk); | |
873 | kexec_flush_icache_page(page); | |
874 | kunmap(page); | |
875 | if (result) { | |
876 | result = -EFAULT; | |
877 | goto out; | |
878 | } | |
879 | ubytes -= uchunk; | |
880 | maddr += mchunk; | |
881 | if (image->file_mode) | |
882 | kbuf += mchunk; | |
883 | else | |
884 | buf += mchunk; | |
885 | mbytes -= mchunk; | |
886 | } | |
887 | out: | |
888 | return result; | |
889 | } | |
890 | ||
891 | int kimage_load_segment(struct kimage *image, | |
892 | struct kexec_segment *segment) | |
893 | { | |
894 | int result = -ENOMEM; | |
895 | ||
896 | switch (image->type) { | |
897 | case KEXEC_TYPE_DEFAULT: | |
898 | result = kimage_load_normal_segment(image, segment); | |
899 | break; | |
900 | case KEXEC_TYPE_CRASH: | |
901 | result = kimage_load_crash_segment(image, segment); | |
902 | break; | |
903 | } | |
904 | ||
905 | return result; | |
906 | } | |
907 | ||
908 | struct kimage *kexec_image; | |
909 | struct kimage *kexec_crash_image; | |
910 | int kexec_load_disabled; | |
911 | ||
7bbee5ca HK |
912 | /* |
913 | * No panic_cpu check version of crash_kexec(). This function is called | |
914 | * only when panic_cpu holds the current CPU number; this is the only CPU | |
915 | * which processes crash_kexec routines. | |
916 | */ | |
c207aee4 | 917 | void __noclone __crash_kexec(struct pt_regs *regs) |
2965faa5 DY |
918 | { |
919 | /* Take the kexec_mutex here to prevent sys_kexec_load | |
920 | * running on one cpu from replacing the crash kernel | |
921 | * we are using after a panic on a different cpu. | |
922 | * | |
923 | * If the crash kernel was not located in a fixed area | |
924 | * of memory the xchg(&kexec_crash_image) would be | |
925 | * sufficient. But since I reuse the memory... | |
926 | */ | |
927 | if (mutex_trylock(&kexec_mutex)) { | |
928 | if (kexec_crash_image) { | |
929 | struct pt_regs fixed_regs; | |
930 | ||
931 | crash_setup_regs(&fixed_regs, regs); | |
932 | crash_save_vmcoreinfo(); | |
933 | machine_crash_shutdown(&fixed_regs); | |
934 | machine_kexec(kexec_crash_image); | |
935 | } | |
936 | mutex_unlock(&kexec_mutex); | |
937 | } | |
938 | } | |
c207aee4 | 939 | STACK_FRAME_NON_STANDARD(__crash_kexec); |
2965faa5 | 940 | |
7bbee5ca HK |
941 | void crash_kexec(struct pt_regs *regs) |
942 | { | |
943 | int old_cpu, this_cpu; | |
944 | ||
945 | /* | |
946 | * Only one CPU is allowed to execute the crash_kexec() code as with | |
947 | * panic(). Otherwise parallel calls of panic() and crash_kexec() | |
948 | * may stop each other. To exclude them, we use panic_cpu here too. | |
949 | */ | |
950 | this_cpu = raw_smp_processor_id(); | |
951 | old_cpu = atomic_cmpxchg(&panic_cpu, PANIC_CPU_INVALID, this_cpu); | |
952 | if (old_cpu == PANIC_CPU_INVALID) { | |
953 | /* This is the 1st CPU which comes here, so go ahead. */ | |
f92bac3b | 954 | printk_safe_flush_on_panic(); |
7bbee5ca HK |
955 | __crash_kexec(regs); |
956 | ||
957 | /* | |
958 | * Reset panic_cpu to allow another panic()/crash_kexec() | |
959 | * call. | |
960 | */ | |
961 | atomic_set(&panic_cpu, PANIC_CPU_INVALID); | |
962 | } | |
963 | } | |
964 | ||
2965faa5 DY |
965 | size_t crash_get_memory_size(void) |
966 | { | |
967 | size_t size = 0; | |
968 | ||
969 | mutex_lock(&kexec_mutex); | |
970 | if (crashk_res.end != crashk_res.start) | |
971 | size = resource_size(&crashk_res); | |
972 | mutex_unlock(&kexec_mutex); | |
973 | return size; | |
974 | } | |
975 | ||
976 | void __weak crash_free_reserved_phys_range(unsigned long begin, | |
977 | unsigned long end) | |
978 | { | |
979 | unsigned long addr; | |
980 | ||
981 | for (addr = begin; addr < end; addr += PAGE_SIZE) | |
43546d86 | 982 | free_reserved_page(boot_pfn_to_page(addr >> PAGE_SHIFT)); |
2965faa5 DY |
983 | } |
984 | ||
985 | int crash_shrink_memory(unsigned long new_size) | |
986 | { | |
987 | int ret = 0; | |
988 | unsigned long start, end; | |
989 | unsigned long old_size; | |
990 | struct resource *ram_res; | |
991 | ||
992 | mutex_lock(&kexec_mutex); | |
993 | ||
994 | if (kexec_crash_image) { | |
995 | ret = -ENOENT; | |
996 | goto unlock; | |
997 | } | |
998 | start = crashk_res.start; | |
999 | end = crashk_res.end; | |
1000 | old_size = (end == 0) ? 0 : end - start + 1; | |
1001 | if (new_size >= old_size) { | |
1002 | ret = (new_size == old_size) ? 0 : -EINVAL; | |
1003 | goto unlock; | |
1004 | } | |
1005 | ||
1006 | ram_res = kzalloc(sizeof(*ram_res), GFP_KERNEL); | |
1007 | if (!ram_res) { | |
1008 | ret = -ENOMEM; | |
1009 | goto unlock; | |
1010 | } | |
1011 | ||
1012 | start = roundup(start, KEXEC_CRASH_MEM_ALIGN); | |
1013 | end = roundup(start + new_size, KEXEC_CRASH_MEM_ALIGN); | |
1014 | ||
2965faa5 DY |
1015 | crash_free_reserved_phys_range(end, crashk_res.end); |
1016 | ||
1017 | if ((start == end) && (crashk_res.parent != NULL)) | |
1018 | release_resource(&crashk_res); | |
1019 | ||
1020 | ram_res->start = end; | |
1021 | ram_res->end = crashk_res.end; | |
1a085d07 | 1022 | ram_res->flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM; |
2965faa5 DY |
1023 | ram_res->name = "System RAM"; |
1024 | ||
1025 | crashk_res.end = end - 1; | |
1026 | ||
1027 | insert_resource(&iomem_resource, ram_res); | |
2965faa5 DY |
1028 | |
1029 | unlock: | |
1030 | mutex_unlock(&kexec_mutex); | |
1031 | return ret; | |
1032 | } | |
1033 | ||
2965faa5 DY |
1034 | void crash_save_cpu(struct pt_regs *regs, int cpu) |
1035 | { | |
1036 | struct elf_prstatus prstatus; | |
1037 | u32 *buf; | |
1038 | ||
1039 | if ((cpu < 0) || (cpu >= nr_cpu_ids)) | |
1040 | return; | |
1041 | ||
1042 | /* Using ELF notes here is opportunistic. | |
1043 | * I need a well defined structure format | |
1044 | * for the data I pass, and I need tags | |
1045 | * on the data to indicate what information I have | |
1046 | * squirrelled away. ELF notes happen to provide | |
1047 | * all of that, so there is no need to invent something new. | |
1048 | */ | |
1049 | buf = (u32 *)per_cpu_ptr(crash_notes, cpu); | |
1050 | if (!buf) | |
1051 | return; | |
1052 | memset(&prstatus, 0, sizeof(prstatus)); | |
1053 | prstatus.pr_pid = current->pid; | |
1054 | elf_core_copy_kernel_regs(&prstatus.pr_reg, regs); | |
1055 | buf = append_elf_note(buf, KEXEC_CORE_NOTE_NAME, NT_PRSTATUS, | |
1056 | &prstatus, sizeof(prstatus)); | |
1057 | final_note(buf); | |
1058 | } | |
1059 | ||
1060 | static int __init crash_notes_memory_init(void) | |
1061 | { | |
1062 | /* Allocate memory for saving cpu registers. */ | |
bbb78b8f BH |
1063 | size_t size, align; |
1064 | ||
1065 | /* | |
1066 | * crash_notes could be allocated across 2 vmalloc pages when percpu | |
1067 | * is vmalloc based . vmalloc doesn't guarantee 2 continuous vmalloc | |
1068 | * pages are also on 2 continuous physical pages. In this case the | |
1069 | * 2nd part of crash_notes in 2nd page could be lost since only the | |
1070 | * starting address and size of crash_notes are exported through sysfs. | |
1071 | * Here round up the size of crash_notes to the nearest power of two | |
1072 | * and pass it to __alloc_percpu as align value. This can make sure | |
1073 | * crash_notes is allocated inside one physical page. | |
1074 | */ | |
1075 | size = sizeof(note_buf_t); | |
1076 | align = min(roundup_pow_of_two(sizeof(note_buf_t)), PAGE_SIZE); | |
1077 | ||
1078 | /* | |
1079 | * Break compile if size is bigger than PAGE_SIZE since crash_notes | |
1080 | * definitely will be in 2 pages with that. | |
1081 | */ | |
1082 | BUILD_BUG_ON(size > PAGE_SIZE); | |
1083 | ||
1084 | crash_notes = __alloc_percpu(size, align); | |
2965faa5 | 1085 | if (!crash_notes) { |
de90a6bc | 1086 | pr_warn("Memory allocation for saving cpu register states failed\n"); |
2965faa5 DY |
1087 | return -ENOMEM; |
1088 | } | |
1089 | return 0; | |
1090 | } | |
1091 | subsys_initcall(crash_notes_memory_init); | |
1092 | ||
1093 | ||
2965faa5 DY |
1094 | /* |
1095 | * Move into place and start executing a preloaded standalone | |
1096 | * executable. If nothing was preloaded return an error. | |
1097 | */ | |
1098 | int kernel_kexec(void) | |
1099 | { | |
1100 | int error = 0; | |
1101 | ||
1102 | if (!mutex_trylock(&kexec_mutex)) | |
1103 | return -EBUSY; | |
1104 | if (!kexec_image) { | |
1105 | error = -EINVAL; | |
1106 | goto Unlock; | |
1107 | } | |
1108 | ||
1109 | #ifdef CONFIG_KEXEC_JUMP | |
1110 | if (kexec_image->preserve_context) { | |
1111 | lock_system_sleep(); | |
1112 | pm_prepare_console(); | |
1113 | error = freeze_processes(); | |
1114 | if (error) { | |
1115 | error = -EBUSY; | |
1116 | goto Restore_console; | |
1117 | } | |
1118 | suspend_console(); | |
1119 | error = dpm_suspend_start(PMSG_FREEZE); | |
1120 | if (error) | |
1121 | goto Resume_console; | |
1122 | /* At this point, dpm_suspend_start() has been called, | |
1123 | * but *not* dpm_suspend_end(). We *must* call | |
1124 | * dpm_suspend_end() now. Otherwise, drivers for | |
1125 | * some devices (e.g. interrupt controllers) become | |
1126 | * desynchronized with the actual state of the | |
1127 | * hardware at resume time, and evil weirdness ensues. | |
1128 | */ | |
1129 | error = dpm_suspend_end(PMSG_FREEZE); | |
1130 | if (error) | |
1131 | goto Resume_devices; | |
1132 | error = disable_nonboot_cpus(); | |
1133 | if (error) | |
1134 | goto Enable_cpus; | |
1135 | local_irq_disable(); | |
1136 | error = syscore_suspend(); | |
1137 | if (error) | |
1138 | goto Enable_irqs; | |
1139 | } else | |
1140 | #endif | |
1141 | { | |
1142 | kexec_in_progress = true; | |
1143 | kernel_restart_prepare(NULL); | |
1144 | migrate_to_reboot_cpu(); | |
1145 | ||
1146 | /* | |
1147 | * migrate_to_reboot_cpu() disables CPU hotplug assuming that | |
1148 | * no further code needs to use CPU hotplug (which is true in | |
1149 | * the reboot case). However, the kexec path depends on using | |
1150 | * CPU hotplug again; so re-enable it here. | |
1151 | */ | |
1152 | cpu_hotplug_enable(); | |
1153 | pr_emerg("Starting new kernel\n"); | |
1154 | machine_shutdown(); | |
1155 | } | |
1156 | ||
1157 | machine_kexec(kexec_image); | |
1158 | ||
1159 | #ifdef CONFIG_KEXEC_JUMP | |
1160 | if (kexec_image->preserve_context) { | |
1161 | syscore_resume(); | |
1162 | Enable_irqs: | |
1163 | local_irq_enable(); | |
1164 | Enable_cpus: | |
1165 | enable_nonboot_cpus(); | |
1166 | dpm_resume_start(PMSG_RESTORE); | |
1167 | Resume_devices: | |
1168 | dpm_resume_end(PMSG_RESTORE); | |
1169 | Resume_console: | |
1170 | resume_console(); | |
1171 | thaw_processes(); | |
1172 | Restore_console: | |
1173 | pm_restore_console(); | |
1174 | unlock_system_sleep(); | |
1175 | } | |
1176 | #endif | |
1177 | ||
1178 | Unlock: | |
1179 | mutex_unlock(&kexec_mutex); | |
1180 | return error; | |
1181 | } | |
1182 | ||
1183 | /* | |
7a0058ec XP |
1184 | * Protection mechanism for crashkernel reserved memory after |
1185 | * the kdump kernel is loaded. | |
2965faa5 DY |
1186 | * |
1187 | * Provide an empty default implementation here -- architecture | |
1188 | * code may override this | |
1189 | */ | |
9b492cf5 XP |
1190 | void __weak arch_kexec_protect_crashkres(void) |
1191 | {} | |
1192 | ||
1193 | void __weak arch_kexec_unprotect_crashkres(void) | |
1194 | {} |