| 1 | |
| 2 | * kexec.c - kexec system call
|
| 3 | * Copyright (C) 2002-2004 Eric Biederman <[email protected]>
|
| 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 |
|
| 9 | #include <linux/capability.h>
|
| 10 | #include <linux/mm.h>
|
| 11 | #include <linux/file.h>
|
| 12 | #include <linux/slab.h>
|
| 13 | #include <linux/fs.h>
|
| 14 | #include <linux/kexec.h>
|
| 15 | #include <linux/spinlock.h>
|
| 16 | #include <linux/list.h>
|
| 17 | #include <linux/highmem.h>
|
| 18 | #include <linux/syscalls.h>
|
| 19 | #include <linux/reboot.h>
|
| 20 | #include <linux/syscalls.h>
|
| 21 | #include <linux/ioport.h>
|
| 22 | #include <linux/hardirq.h>
|
| 23 | #include <linux/elf.h>
|
| 24 | #include <linux/elfcore.h>
|
| 25 |
|
| 26 | #include <asm/page.h>
|
| 27 | #include <asm/uaccess.h>
|
| 28 | #include <asm/io.h>
|
| 29 | #include <asm/system.h>
|
| 30 | #include <asm/semaphore.h>
|
| 31 |
|
| 32 |
|
| 33 | note_buf_t* crash_notes;
|
| 34 |
|
| 35 |
|
| 36 | struct resource crashk_res = {
|
| 37 | .name = "Crash kernel",
|
| 38 | .start = 0,
|
| 39 | .end = 0,
|
| 40 | .flags = IORESOURCE_BUSY | IORESOURCE_MEM
|
| 41 | };
|
| 42 |
|
| 43 | int kexec_should_crash(struct task_struct *p)
|
| 44 | {
|
| 45 | if (in_interrupt() || !p->pid || is_init(p) || panic_on_oops)
|
| 46 | return 1;
|
| 47 | return 0;
|
| 48 | }
|
| 49 |
|
| 50 | |
| 51 | * When kexec transitions to the new kernel there is a one-to-one
|
| 52 | * mapping between physical and virtual addresses. On processors
|
| 53 | * where you can disable the MMU this is trivial, and easy. For
|
| 54 | * others it is still a simple predictable page table to setup.
|
| 55 | *
|
| 56 | * In that environment kexec copies the new kernel to its final
|
| 57 | * resting place. This means I can only support memory whose
|
| 58 | * physical address can fit in an unsigned long. In particular
|
| 59 | * addresses where (pfn << PAGE_SHIFT) > ULONG_MAX cannot be handled.
|
| 60 | * If the assembly stub has more restrictive requirements
|
| 61 | * KEXEC_SOURCE_MEMORY_LIMIT and KEXEC_DEST_MEMORY_LIMIT can be
|
| 62 | * defined more restrictively in <asm/kexec.h>.
|
| 63 | *
|
| 64 | * The code for the transition from the current kernel to the
|
| 65 | * the new kernel is placed in the control_code_buffer, whose size
|
| 66 | * is given by KEXEC_CONTROL_CODE_SIZE. In the best case only a single
|
| 67 | * page of memory is necessary, but some architectures require more.
|
| 68 | * Because this memory must be identity mapped in the transition from
|
| 69 | * virtual to physical addresses it must live in the range
|
| 70 | * 0 - TASK_SIZE, as only the user space mappings are arbitrarily
|
| 71 | * modifiable.
|
| 72 | *
|
| 73 | * The assembly stub in the control code buffer is passed a linked list
|
| 74 | * of descriptor pages detailing the source pages of the new kernel,
|
| 75 | * and the destination addresses of those source pages. As this data
|
| 76 | * structure is not used in the context of the current OS, it must
|
| 77 | * be self-contained.
|
| 78 | *
|
| 79 | * The code has been made to work with highmem pages and will use a
|
| 80 | * destination page in its final resting place (if it happens
|
| 81 | * to allocate it). The end product of this is that most of the
|
| 82 | * physical address space, and most of RAM can be used.
|
| 83 | *
|
| 84 | * Future directions include:
|
| 85 | * - allocating a page table with the control code buffer identity
|
| 86 | * mapped, to simplify machine_kexec and make kexec_on_panic more
|
| 87 | * reliable.
|
| 88 |
|
| 89 |
|
| 90 | |
| 91 | * KIMAGE_NO_DEST is an impossible destination address..., for
|
| 92 | * allocating pages whose destination address we do not care about.
|
| 93 |
|
| 94 | #define KIMAGE_NO_DEST (-1UL)
|
| 95 |
|
| 96 | static int kimage_is_destination_range(struct kimage *image,
|
| 97 | unsigned long start, unsigned long end);
|
| 98 | static struct page *kimage_alloc_page(struct kimage *image,
|
| 99 | gfp_t gfp_mask,
|
| 100 | unsigned long dest);
|
| 101 |
|
| 102 | static int do_kimage_alloc(struct kimage **rimage, unsigned long entry,
|
| 103 | unsigned long nr_segments,
|
| 104 | struct kexec_segment __user *segments)
|
| 105 | {
|
| 106 | size_t segment_bytes;
|
| 107 | struct kimage *image;
|
| 108 | unsigned long i;
|
| 109 | int result;
|
| 110 |
|
| 111 |
|
| 112 | result = -ENOMEM;
|
| 113 | image = kzalloc(sizeof(*image), GFP_KERNEL);
|
| 114 | if (!image)
|
| 115 | goto out;
|
| 116 |
|
| 117 | image->head = 0;
|
| 118 | image->entry = &image->head;
|
| 119 | image->last_entry = &image->head;
|
| 120 | image->control_page = ~0;
|
| 121 | image->start = entry;
|
| 122 | image->type = KEXEC_TYPE_DEFAULT;
|
| 123 |
|
| 124 |
|
| 125 | INIT_LIST_HEAD(&image->control_pages);
|
| 126 |
|
| 127 |
|
| 128 | INIT_LIST_HEAD(&image->dest_pages);
|
| 129 |
|
| 130 |
|
| 131 | INIT_LIST_HEAD(&image->unuseable_pages);
|
| 132 |
|
| 133 |
|
| 134 | image->nr_segments = nr_segments;
|
| 135 | segment_bytes = nr_segments * sizeof(*segments);
|
| 136 | result = copy_from_user(image->segment, segments, segment_bytes);
|
| 137 | if (result)
|
| 138 | goto out;
|
| 139 |
|
| 140 | |
| 141 | * Verify we have good destination addresses. The caller is
|
| 142 | * responsible for making certain we don't attempt to load
|
| 143 | * the new image into invalid or reserved areas of RAM. This
|
| 144 | * just verifies it is an address we can use.
|
| 145 | *
|
| 146 | * Since the kernel does everything in page size chunks ensure
|
| 147 | * the destination addreses are page aligned. Too many
|
| 148 | * special cases crop of when we don't do this. The most
|
| 149 | * insidious is getting overlapping destination addresses
|
| 150 | * simply because addresses are changed to page size
|
| 151 | * granularity.
|
| 152 |
|
| 153 | result = -EADDRNOTAVAIL;
|
| 154 | for (i = 0; i < nr_segments; i++) {
|
| 155 | unsigned long mstart, mend;
|
| 156 |
|
| 157 | mstart = image->segment[i].mem;
|
| 158 | mend = mstart + image->segment[i].memsz;
|
| 159 | if ((mstart & ~PAGE_MASK) || (mend & ~PAGE_MASK))
|
| 160 | goto out;
|
| 161 | if (mend >= KEXEC_DESTINATION_MEMORY_LIMIT)
|
| 162 | goto out;
|
| 163 | }
|
| 164 |
|
| 165 | |
| 166 | * If we alloed overlapping destination addresses
|
| 167 | * through very weird things can happen with no
|
| 168 | * easy explanation as one segment stops on another.
|
| 169 |
|
| 170 | result = -EINVAL;
|
| 171 | for (i = 0; i < nr_segments; i++) {
|
| 172 | unsigned long mstart, mend;
|
| 173 | unsigned long j;
|
| 174 |
|
| 175 | mstart = image->segment[i].mem;
|
| 176 | mend = mstart + image->segment[i].memsz;
|
| 177 | for (j = 0; j < i; j++) {
|
| 178 | unsigned long pstart, pend;
|
| 179 | pstart = image->segment[j].mem;
|
| 180 | pend = pstart + image->segment[j].memsz;
|
| 181 |
|
| 182 | if ((mend > pstart) && (mstart < pend))
|
| 183 | goto out;
|
| 184 | }
|
| 185 | }
|
| 186 |
|
| 187 | |
| 188 | * our memory sizes. This should always be the case,
|
| 189 | * and it is easier to check up front than to be surprised
|
| 190 | * later on.
|
| 191 |
|
| 192 | result = -EINVAL;
|
| 193 | for (i = 0; i < nr_segments; i++) {
|
| 194 | if (image->segment[i].bufsz > image->segment[i].memsz)
|
| 195 | goto out;
|
| 196 | }
|
| 197 |
|
| 198 | result = 0;
|
| 199 | out:
|
| 200 | if (result == 0)
|
| 201 | *rimage = image;
|
| 202 | else
|
| 203 | kfree(image);
|
| 204 |
|
| 205 | return result;
|
| 206 |
|
| 207 | }
|
| 208 |
|
| 209 | static int kimage_normal_alloc(struct kimage **rimage, unsigned long entry,
|
| 210 | unsigned long nr_segments,
|
| 211 | struct kexec_segment __user *segments)
|
| 212 | {
|
| 213 | int result;
|
| 214 | struct kimage *image;
|
| 215 |
|
| 216 |
|
| 217 | image = NULL;
|
| 218 | result = do_kimage_alloc(&image, entry, nr_segments, segments);
|
| 219 | if (result)
|
| 220 | goto out;
|
| 221 |
|
| 222 | *rimage = image;
|
| 223 |
|
| 224 | |
| 225 | * Find a location for the control code buffer, and add it
|
| 226 | * the vector of segments so that it's pages will also be
|
| 227 | * counted as destination pages.
|
| 228 |
|
| 229 | result = -ENOMEM;
|
| 230 | image->control_code_page = kimage_alloc_control_pages(image,
|
| 231 | get_order(KEXEC_CONTROL_CODE_SIZE));
|
| 232 | if (!image->control_code_page) {
|
| 233 | printk(KERN_ERR "Could not allocate control_code_buffer\n");
|
| 234 | goto out;
|
| 235 | }
|
| 236 |
|
| 237 | result = 0;
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| 238 | out:
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| 239 | if (result == 0)
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| 240 | *rimage = image;
|
| 241 | else
|
| 242 | kfree(image);
|
| 243 |
|
| 244 | return result;
|
| 245 | }
|
| 246 |
|
| 247 | static int kimage_crash_alloc(struct kimage **rimage, unsigned long entry,
|
| 248 | unsigned long nr_segments,
|
| 249 | struct kexec_segment __user *segments)
|
| 250 | {
|
| 251 | int result;
|
| 252 | struct kimage *image;
|
| 253 | unsigned long i;
|
| 254 |
|
| 255 | image = NULL;
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| 256 |
|
| 257 | if ((entry < crashk_res.start) || (entry > crashk_res.end)) {
|
| 258 | result = -EADDRNOTAVAIL;
|
| 259 | goto out;
|
| 260 | }
|
| 261 |
|
| 262 |
|
| 263 | result = do_kimage_alloc(&image, entry, nr_segments, segments);
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| 264 | if (result)
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| 265 | goto out;
|
| 266 |
|
| 267 | |
| 268 | * allocation policy.
|
| 269 |
|
| 270 | image->control_page = crashk_res.start;
|
| 271 | image->type = KEXEC_TYPE_CRASH;
|
| 272 |
|
| 273 | |
| 274 | * Verify we have good destination addresses. Normally
|
| 275 | * the caller is responsible for making certain we don't
|
| 276 | * attempt to load the new image into invalid or reserved
|
| 277 | * areas of RAM. But crash kernels are preloaded into a
|
| 278 | * reserved area of ram. We must ensure the addresses
|
| 279 | * are in the reserved area otherwise preloading the
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| 280 | * kernel could corrupt things.
|
| 281 |
|
| 282 | result = -EADDRNOTAVAIL;
|
| 283 | for (i = 0; i < nr_segments; i++) {
|
| 284 | unsigned long mstart, mend;
|
| 285 |
|
| 286 | mstart = image->segment[i].mem;
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| 287 | mend = mstart + image->segment[i].memsz - 1;
|
| 288 |
|
| 289 | if ((mstart < crashk_res.start) || (mend > crashk_res.end))
|
| 290 | goto out;
|
| 291 | }
|
| 292 |
|
| 293 | |
| 294 | * Find a location for the control code buffer, and add
|
| 295 | * the vector of segments so that it's pages will also be
|
| 296 | * counted as destination pages.
|
| 297 |
|
| 298 | result = -ENOMEM;
|
| 299 | image->control_code_page = kimage_alloc_control_pages(image,
|
| 300 | get_order(KEXEC_CONTROL_CODE_SIZE));
|
| 301 | if (!image->control_code_page) {
|
| 302 | printk(KERN_ERR "Could not allocate control_code_buffer\n");
|
| 303 | goto out;
|
| 304 | }
|
| 305 |
|
| 306 | result = 0;
|
| 307 | out:
|
| 308 | if (result == 0)
|
| 309 | *rimage = image;
|
| 310 | else
|
| 311 | kfree(image);
|
| 312 |
|
| 313 | return result;
|
| 314 | }
|
| 315 |
|
| 316 | static int kimage_is_destination_range(struct kimage *image,
|
| 317 | unsigned long start,
|
| 318 | unsigned long end)
|
| 319 | {
|
| 320 | unsigned long i;
|
| 321 |
|
| 322 | for (i = 0; i < image->nr_segments; i++) {
|
| 323 | unsigned long mstart, mend;
|
| 324 |
|
| 325 | mstart = image->segment[i].mem;
|
| 326 | mend = mstart + image->segment[i].memsz;
|
| 327 | if ((end > mstart) && (start < mend))
|
| 328 | return 1;
|
| 329 | }
|
| 330 |
|
| 331 | return 0;
|
| 332 | }
|
| 333 |
|
| 334 | static struct page *kimage_alloc_pages(gfp_t gfp_mask, unsigned int order)
|
| 335 | {
|
| 336 | struct page *pages;
|
| 337 |
|
| 338 | pages = alloc_pages(gfp_mask, order);
|
| 339 | if (pages) {
|
| 340 | unsigned int count, i;
|
| 341 | pages->mapping = NULL;
|
| 342 | set_page_private(pages, order);
|
| 343 | count = 1 << order;
|
| 344 | for (i = 0; i < count; i++)
|
| 345 | SetPageReserved(pages + i);
|
| 346 | }
|
| 347 |
|
| 348 | return pages;
|
| 349 | }
|
| 350 |
|
| 351 | static void kimage_free_pages(struct page *page)
|
| 352 | {
|
| 353 | unsigned int order, count, i;
|
| 354 |
|
| 355 | order = page_private(page);
|
| 356 | count = 1 << order;
|
| 357 | for (i = 0; i < count; i++)
|
| 358 | ClearPageReserved(page + i);
|
| 359 | __free_pages(page, order);
|
| 360 | }
|
| 361 |
|
| 362 | static void kimage_free_page_list(struct list_head *list)
|
| 363 | {
|
| 364 | struct list_head *pos, *next;
|
| 365 |
|
| 366 | list_for_each_safe(pos, next, list) {
|
| 367 | struct page *page;
|
| 368 |
|
| 369 | page = list_entry(pos, struct page, lru);
|
| 370 | list_del(&page->lru);
|
| 371 | kimage_free_pages(page);
|
| 372 | }
|
| 373 | }
|
| 374 |
|
| 375 | static struct page *kimage_alloc_normal_control_pages(struct kimage *image,
|
| 376 | unsigned int order)
|
| 377 | {
|
| 378 | |
| 379 | * that are needed while we copy the rest of the pages
|
| 380 | * to their final resting place. As such they must
|
| 381 | * not conflict with either the destination addresses
|
| 382 | * or memory the kernel is already using.
|
| 383 | *
|
| 384 | * The only case where we really need more than one of
|
| 385 | * these are for architectures where we cannot disable
|
| 386 | * the MMU and must instead generate an identity mapped
|
| 387 | * page table for all of the memory.
|
| 388 | *
|
| 389 | * At worst this runs in O(N) of the image size.
|
| 390 |
|
| 391 | struct list_head extra_pages;
|
| 392 | struct page *pages;
|
| 393 | unsigned int count;
|
| 394 |
|
| 395 | count = 1 << order;
|
| 396 | INIT_LIST_HEAD(&extra_pages);
|
| 397 |
|
| 398 | |
| 399 | * is a destination page.
|
| 400 |
|
| 401 | do {
|
| 402 | unsigned long pfn, epfn, addr, eaddr;
|
| 403 |
|
| 404 | pages = kimage_alloc_pages(GFP_KERNEL, order);
|
| 405 | if (!pages)
|
| 406 | break;
|
| 407 | pfn = page_to_pfn(pages);
|
| 408 | epfn = pfn + count;
|
| 409 | addr = pfn << PAGE_SHIFT;
|
| 410 | eaddr = epfn << PAGE_SHIFT;
|
| 411 | if ((epfn >= (KEXEC_CONTROL_MEMORY_LIMIT >> PAGE_SHIFT)) ||
|
| 412 | kimage_is_destination_range(image, addr, eaddr)) {
|
| 413 | list_add(&pages->lru, &extra_pages);
|
| 414 | pages = NULL;
|
| 415 | }
|
| 416 | } while (!pages);
|
| 417 |
|
| 418 | if (pages) {
|
| 419 |
|
| 420 | list_add(&pages->lru, &image->control_pages);
|
| 421 |
|
| 422 | |
| 423 | * location we will never allocate another page at
|
| 424 | * that address. Therefore kimage_alloc_pages
|
| 425 | * will not return it (again) and we don't need
|
| 426 | * to give it an entry in image->segment[].
|
| 427 |
|
| 428 | }
|
| 429 | |
| 430 | *
|
| 431 | * Ideally I would convert multi-page allocations into single
|
| 432 | * page allocations, and add everyting to image->dest_pages.
|
| 433 | *
|
| 434 | * For now it is simpler to just free the pages.
|
| 435 |
|
| 436 | kimage_free_page_list(&extra_pages);
|
| 437 |
|
| 438 | return pages;
|
| 439 | }
|
| 440 |
|
| 441 | static struct page *kimage_alloc_crash_control_pages(struct kimage *image,
|
| 442 | unsigned int order)
|
| 443 | {
|
| 444 | |
| 445 | * that are needed while we copy the rest of the pages
|
| 446 | * to their final resting place. As such they must
|
| 447 | * not conflict with either the destination addresses
|
| 448 | * or memory the kernel is already using.
|
| 449 | *
|
| 450 | * Control pages are also the only pags we must allocate
|
| 451 | * when loading a crash kernel. All of the other pages
|
| 452 | * are specified by the segments and we just memcpy
|
| 453 | * into them directly.
|
| 454 | *
|
| 455 | * The only case where we really need more than one of
|
| 456 | * these are for architectures where we cannot disable
|
| 457 | * the MMU and must instead generate an identity mapped
|
| 458 | * page table for all of the memory.
|
| 459 | *
|
| 460 | * Given the low demand this implements a very simple
|
| 461 | * allocator that finds the first hole of the appropriate
|
| 462 | * size in the reserved memory region, and allocates all
|
| 463 | * of the memory up to and including the hole.
|
| 464 |
|
| 465 | unsigned long hole_start, hole_end, size;
|
| 466 | struct page *pages;
|
| 467 |
|
| 468 | pages = NULL;
|
| 469 | size = (1 << order) << PAGE_SHIFT;
|
| 470 | hole_start = (image->control_page + (size - 1)) & ~(size - 1);
|
| 471 | hole_end = hole_start + size - 1;
|
| 472 | while (hole_end <= crashk_res.end) {
|
| 473 | unsigned long i;
|
| 474 |
|
| 475 | if (hole_end > KEXEC_CONTROL_MEMORY_LIMIT)
|
| 476 | break;
|
| 477 | if (hole_end > crashk_res.end)
|
| 478 | break;
|
| 479 |
|
| 480 | for (i = 0; i < image->nr_segments; i++) {
|
| 481 | unsigned long mstart, mend;
|
| 482 |
|
| 483 | mstart = image->segment[i].mem;
|
| 484 | mend = mstart + image->segment[i].memsz - 1;
|
| 485 | if ((hole_end >= mstart) && (hole_start <= mend)) {
|
| 486 |
|
| 487 | hole_start = (mend + (size - 1)) & ~(size - 1);
|
| 488 | hole_end = hole_start + size - 1;
|
| 489 | break;
|
| 490 | }
|
| 491 | }
|
| 492 |
|
| 493 | if (i == image->nr_segments) {
|
| 494 | pages = pfn_to_page(hole_start >> PAGE_SHIFT);
|
| 495 | break;
|
| 496 | }
|
| 497 | }
|
| 498 | if (pages)
|
| 499 | image->control_page = hole_end;
|
| 500 |
|
| 501 | return pages;
|
| 502 | }
|
| 503 |
|
| 504 |
|
| 505 | struct page *kimage_alloc_control_pages(struct kimage *image,
|
| 506 | unsigned int order)
|
| 507 | {
|
| 508 | struct page *pages = NULL;
|
| 509 |
|
| 510 | switch (image->type) {
|
| 511 | case KEXEC_TYPE_DEFAULT:
|
| 512 | pages = kimage_alloc_normal_control_pages(image, order);
|
| 513 | break;
|
| 514 | case KEXEC_TYPE_CRASH:
|
| 515 | pages = kimage_alloc_crash_control_pages(image, order);
|
| 516 | break;
|
| 517 | }
|
| 518 |
|
| 519 | return pages;
|
| 520 | }
|
| 521 |
|
| 522 | static int kimage_add_entry(struct kimage *image, kimage_entry_t entry)
|
| 523 | {
|
| 524 | if (*image->entry != 0)
|
| 525 | image->entry++;
|
| 526 |
|
| 527 | if (image->entry == image->last_entry) {
|
| 528 | kimage_entry_t *ind_page;
|
| 529 | struct page *page;
|
| 530 |
|
| 531 | page = kimage_alloc_page(image, GFP_KERNEL, KIMAGE_NO_DEST);
|
| 532 | if (!page)
|
| 533 | return -ENOMEM;
|
| 534 |
|
| 535 | ind_page = page_address(page);
|
| 536 | *image->entry = virt_to_phys(ind_page) | IND_INDIRECTION;
|
| 537 | image->entry = ind_page;
|
| 538 | image->last_entry = ind_page +
|
| 539 | ((PAGE_SIZE/sizeof(kimage_entry_t)) - 1);
|
| 540 | }
|
| 541 | *image->entry = entry;
|
| 542 | image->entry++;
|
| 543 | *image->entry = 0;
|
| 544 |
|
| 545 | return 0;
|
| 546 | }
|
| 547 |
|
| 548 | static int kimage_set_destination(struct kimage *image,
|
| 549 | unsigned long destination)
|
| 550 | {
|
| 551 | int result;
|
| 552 |
|
| 553 | destination &= PAGE_MASK;
|
| 554 | result = kimage_add_entry(image, destination | IND_DESTINATION);
|
| 555 | if (result == 0)
|
| 556 | image->destination = destination;
|
| 557 |
|
| 558 | return result;
|
| 559 | }
|
| 560 |
|
| 561 |
|
| 562 | static int kimage_add_page(struct kimage *image, unsigned long page)
|
| 563 | {
|
| 564 | int result;
|
| 565 |
|
| 566 | page &= PAGE_MASK;
|
| 567 | result = kimage_add_entry(image, page | IND_SOURCE);
|
| 568 | if (result == 0)
|
| 569 | image->destination += PAGE_SIZE;
|
| 570 |
|
| 571 | return result;
|
| 572 | }
|
| 573 |
|
| 574 |
|
| 575 | static void kimage_free_extra_pages(struct kimage *image)
|
| 576 | {
|
| 577 |
|
| 578 | kimage_free_page_list(&image->dest_pages);
|
| 579 |
|
| 580 |
|
| 581 | kimage_free_page_list(&image->unuseable_pages);
|
| 582 |
|
| 583 | }
|
| 584 | static int kimage_terminate(struct kimage *image)
|
| 585 | {
|
| 586 | if (*image->entry != 0)
|
| 587 | image->entry++;
|
| 588 |
|
| 589 | *image->entry = IND_DONE;
|
| 590 |
|
| 591 | return 0;
|
| 592 | }
|
| 593 |
|
| 594 | #define for_each_kimage_entry(image, ptr, entry) \
|
| 595 | for (ptr = &image->head; (entry = *ptr) && !(entry & IND_DONE); \
|
| 596 | ptr = (entry & IND_INDIRECTION)? \
|
| 597 | phys_to_virt((entry & PAGE_MASK)): ptr +1)
|
| 598 |
|
| 599 | static void kimage_free_entry(kimage_entry_t entry)
|
| 600 | {
|
| 601 | struct page *page;
|
| 602 |
|
| 603 | page = pfn_to_page(entry >> PAGE_SHIFT);
|
| 604 | kimage_free_pages(page);
|
| 605 | }
|
| 606 |
|
| 607 | static void kimage_free(struct kimage *image)
|
| 608 | {
|
| 609 | kimage_entry_t *ptr, entry;
|
| 610 | kimage_entry_t ind = 0;
|
| 611 |
|
| 612 | if (!image)
|
| 613 | return;
|
| 614 |
|
| 615 | kimage_free_extra_pages(image);
|
| 616 | for_each_kimage_entry(image, ptr, entry) {
|
| 617 | if (entry & IND_INDIRECTION) {
|
| 618 |
|
| 619 | if (ind & IND_INDIRECTION)
|
| 620 | kimage_free_entry(ind);
|
| 621 | |
| 622 | * done with it.
|
| 623 |
|
| 624 | ind = entry;
|
| 625 | }
|
| 626 | else if (entry & IND_SOURCE)
|
| 627 | kimage_free_entry(entry);
|
| 628 | }
|
| 629 |
|
| 630 | if (ind & IND_INDIRECTION)
|
| 631 | kimage_free_entry(ind);
|
| 632 |
|
| 633 |
|
| 634 | machine_kexec_cleanup(image);
|
| 635 |
|
| 636 |
|
| 637 | kimage_free_page_list(&image->control_pages);
|
| 638 | kfree(image);
|
| 639 | }
|
| 640 |
|
| 641 | static kimage_entry_t *kimage_dst_used(struct kimage *image,
|
| 642 | unsigned long page)
|
| 643 | {
|
| 644 | kimage_entry_t *ptr, entry;
|
| 645 | unsigned long destination = 0;
|
| 646 |
|
| 647 | for_each_kimage_entry(image, ptr, entry) {
|
| 648 | if (entry & IND_DESTINATION)
|
| 649 | destination = entry & PAGE_MASK;
|
| 650 | else if (entry & IND_SOURCE) {
|
| 651 | if (page == destination)
|
| 652 | return ptr;
|
| 653 | destination += PAGE_SIZE;
|
| 654 | }
|
| 655 | }
|
| 656 |
|
| 657 | return NULL;
|
| 658 | }
|
| 659 |
|
| 660 | static struct page *kimage_alloc_page(struct kimage *image,
|
| 661 | gfp_t gfp_mask,
|
| 662 | unsigned long destination)
|
| 663 | {
|
| 664 | |
| 665 | * Here we implement safeguards to ensure that a source page
|
| 666 | * is not copied to its destination page before the data on
|
| 667 | * the destination page is no longer useful.
|
| 668 | *
|
| 669 | * To do this we maintain the invariant that a source page is
|
| 670 | * either its own destination page, or it is not a
|
| 671 | * destination page at all.
|
| 672 | *
|
| 673 | * That is slightly stronger than required, but the proof
|
| 674 | * that no problems will not occur is trivial, and the
|
| 675 | * implementation is simply to verify.
|
| 676 | *
|
| 677 | * When allocating all pages normally this algorithm will run
|
| 678 | * in O(N) time, but in the worst case it will run in O(N^2)
|
| 679 | * time. If the runtime is a problem the data structures can
|
| 680 | * be fixed.
|
| 681 |
|
| 682 | struct page *page;
|
| 683 | unsigned long addr;
|
| 684 |
|
| 685 | |
| 686 | * Walk through the list of destination pages, and see if I
|
| 687 | * have a match.
|
| 688 |
|
| 689 | list_for_each_entry(page, &image->dest_pages, lru) {
|
| 690 | addr = page_to_pfn(page) << PAGE_SHIFT;
|
| 691 | if (addr == destination) {
|
| 692 | list_del(&page->lru);
|
| 693 | return page;
|
| 694 | }
|
| 695 | }
|
| 696 | page = NULL;
|
| 697 | while (1) {
|
| 698 | kimage_entry_t *old;
|
| 699 |
|
| 700 |
|
| 701 | page = kimage_alloc_pages(gfp_mask, 0);
|
| 702 | if (!page)
|
| 703 | return NULL;
|
| 704 |
|
| 705 | if (page_to_pfn(page) >
|
| 706 | (KEXEC_SOURCE_MEMORY_LIMIT >> PAGE_SHIFT)) {
|
| 707 | list_add(&page->lru, &image->unuseable_pages);
|
| 708 | continue;
|
| 709 | }
|
| 710 | addr = page_to_pfn(page) << PAGE_SHIFT;
|
| 711 |
|
| 712 |
|
| 713 | if (addr == destination)
|
| 714 | break;
|
| 715 |
|
| 716 |
|
| 717 | if (!kimage_is_destination_range(image, addr,
|
| 718 | addr + PAGE_SIZE))
|
| 719 | break;
|
| 720 |
|
| 721 | |
| 722 | * I know that the page is someones destination page.
|
| 723 | * See if there is already a source page for this
|
| 724 | * destination page. And if so swap the source pages.
|
| 725 |
|
| 726 | old = kimage_dst_used(image, addr);
|
| 727 | if (old) {
|
| 728 |
|
| 729 | unsigned long old_addr;
|
| 730 | struct page *old_page;
|
| 731 |
|
| 732 | old_addr = *old & PAGE_MASK;
|
| 733 | old_page = pfn_to_page(old_addr >> PAGE_SHIFT);
|
| 734 | copy_highpage(page, old_page);
|
| 735 | *old = addr | (*old & ~PAGE_MASK);
|
| 736 |
|
| 737 | |
| 738 | * destination page, so return it.
|
| 739 |
|
| 740 | addr = old_addr;
|
| 741 | page = old_page;
|
| 742 | break;
|
| 743 | }
|
| 744 | else {
|
| 745 | |
| 746 | * will use it later.
|
| 747 |
|
| 748 | list_add(&page->lru, &image->dest_pages);
|
| 749 | }
|
| 750 | }
|
| 751 |
|
| 752 | return page;
|
| 753 | }
|
| 754 |
|
| 755 | static int kimage_load_normal_segment(struct kimage *image,
|
| 756 | struct kexec_segment *segment)
|
| 757 | {
|
| 758 | unsigned long maddr;
|
| 759 | unsigned long ubytes, mbytes;
|
| 760 | int result;
|
| 761 | unsigned char __user *buf;
|
| 762 |
|
| 763 | result = 0;
|
| 764 | buf = segment->buf;
|
| 765 | ubytes = segment->bufsz;
|
| 766 | mbytes = segment->memsz;
|
| 767 | maddr = segment->mem;
|
| 768 |
|
| 769 | result = kimage_set_destination(image, maddr);
|
| 770 | if (result < 0)
|
| 771 | goto out;
|
| 772 |
|
| 773 | while (mbytes) {
|
| 774 | struct page *page;
|
| 775 | char *ptr;
|
| 776 | size_t uchunk, mchunk;
|
| 777 |
|
| 778 | page = kimage_alloc_page(image, GFP_HIGHUSER, maddr);
|
| 779 | if (page == 0) {
|
| 780 | result = -ENOMEM;
|
| 781 | goto out;
|
| 782 | }
|
| 783 | result = kimage_add_page(image, page_to_pfn(page)
|
| 784 | << PAGE_SHIFT);
|
| 785 | if (result < 0)
|
| 786 | goto out;
|
| 787 |
|
| 788 | ptr = kmap(page);
|
| 789 |
|
| 790 | memset(ptr, 0, PAGE_SIZE);
|
| 791 | ptr += maddr & ~PAGE_MASK;
|
| 792 | mchunk = PAGE_SIZE - (maddr & ~PAGE_MASK);
|
| 793 | if (mchunk > mbytes)
|
| 794 | mchunk = mbytes;
|
| 795 |
|
| 796 | uchunk = mchunk;
|
| 797 | if (uchunk > ubytes)
|
| 798 | uchunk = ubytes;
|
| 799 |
|
| 800 | result = copy_from_user(ptr, buf, uchunk);
|
| 801 | kunmap(page);
|
| 802 | if (result) {
|
| 803 | result = (result < 0) ? result : -EIO;
|
| 804 | goto out;
|
| 805 | }
|
| 806 | ubytes -= uchunk;
|
| 807 | maddr += mchunk;
|
| 808 | buf += mchunk;
|
| 809 | mbytes -= mchunk;
|
| 810 | }
|
| 811 | out:
|
| 812 | return result;
|
| 813 | }
|
| 814 |
|
| 815 | static int kimage_load_crash_segment(struct kimage *image,
|
| 816 | struct kexec_segment *segment)
|
| 817 | {
|
| 818 | |
| 819 | * user space to it's destination.
|
| 820 | * We do things a page at a time for the sake of kmap.
|
| 821 |
|
| 822 | unsigned long maddr;
|
| 823 | unsigned long ubytes, mbytes;
|
| 824 | int result;
|
| 825 | unsigned char __user *buf;
|
| 826 |
|
| 827 | result = 0;
|
| 828 | buf = segment->buf;
|
| 829 | ubytes = segment->bufsz;
|
| 830 | mbytes = segment->memsz;
|
| 831 | maddr = segment->mem;
|
| 832 | while (mbytes) {
|
| 833 | struct page *page;
|
| 834 | char *ptr;
|
| 835 | size_t uchunk, mchunk;
|
| 836 |
|
| 837 | page = pfn_to_page(maddr >> PAGE_SHIFT);
|
| 838 | if (page == 0) {
|
| 839 | result = -ENOMEM;
|
| 840 | goto out;
|
| 841 | }
|
| 842 | ptr = kmap(page);
|
| 843 | ptr += maddr & ~PAGE_MASK;
|
| 844 | mchunk = PAGE_SIZE - (maddr & ~PAGE_MASK);
|
| 845 | if (mchunk > mbytes)
|
| 846 | mchunk = mbytes;
|
| 847 |
|
| 848 | uchunk = mchunk;
|
| 849 | if (uchunk > ubytes) {
|
| 850 | uchunk = ubytes;
|
| 851 |
|
| 852 | memset(ptr + uchunk, 0, mchunk - uchunk);
|
| 853 | }
|
| 854 | result = copy_from_user(ptr, buf, uchunk);
|
| 855 | kexec_flush_icache_page(page);
|
| 856 | kunmap(page);
|
| 857 | if (result) {
|
| 858 | result = (result < 0) ? result : -EIO;
|
| 859 | goto out;
|
| 860 | }
|
| 861 | ubytes -= uchunk;
|
| 862 | maddr += mchunk;
|
| 863 | buf += mchunk;
|
| 864 | mbytes -= mchunk;
|
| 865 | }
|
| 866 | out:
|
| 867 | return result;
|
| 868 | }
|
| 869 |
|
| 870 | static int kimage_load_segment(struct kimage *image,
|
| 871 | struct kexec_segment *segment)
|
| 872 | {
|
| 873 | int result = -ENOMEM;
|
| 874 |
|
| 875 | switch (image->type) {
|
| 876 | case KEXEC_TYPE_DEFAULT:
|
| 877 | result = kimage_load_normal_segment(image, segment);
|
| 878 | break;
|
| 879 | case KEXEC_TYPE_CRASH:
|
| 880 | result = kimage_load_crash_segment(image, segment);
|
| 881 | break;
|
| 882 | }
|
| 883 |
|
| 884 | return result;
|
| 885 | }
|
| 886 |
|
| 887 | |
| 888 | * Exec Kernel system call: for obvious reasons only root may call it.
|
| 889 | *
|
| 890 | * This call breaks up into three pieces.
|
| 891 | * - A generic part which loads the new kernel from the current
|
| 892 | * address space, and very carefully places the data in the
|
| 893 | * allocated pages.
|
| 894 | *
|
| 895 | * - A generic part that interacts with the kernel and tells all of
|
| 896 | * the devices to shut down. Preventing on-going dmas, and placing
|
| 897 | * the devices in a consistent state so a later kernel can
|
| 898 | * reinitialize them.
|
| 899 | *
|
| 900 | * - A machine specific part that includes the syscall number
|
| 901 | * and the copies the image to it's final destination. And
|
| 902 | * jumps into the image at entry.
|
| 903 | *
|
| 904 | * kexec does not sync, or unmount filesystems so if you need
|
| 905 | * that to happen you need to do that yourself.
|
| 906 |
|
| 907 | struct kimage *kexec_image;
|
| 908 | struct kimage *kexec_crash_image;
|
| 909 | |
| 910 | * A home grown binary mutex.
|
| 911 | * Nothing can wait so this mutex is safe to use
|
| 912 | * in interrupt context :)
|
| 913 |
|
| 914 | static int kexec_lock;
|
| 915 |
|
| 916 | asmlinkage long sys_kexec_load(unsigned long entry, unsigned long nr_segments,
|
| 917 | struct kexec_segment __user *segments,
|
| 918 | unsigned long flags)
|
| 919 | {
|
| 920 | struct kimage **dest_image, *image;
|
| 921 | int locked;
|
| 922 | int result;
|
| 923 |
|
| 924 |
|
| 925 | if (!capable(CAP_SYS_BOOT))
|
| 926 | return -EPERM;
|
| 927 |
|
| 928 | |
| 929 | * Verify we have a legal set of flags
|
| 930 | * This leaves us room for future extensions.
|
| 931 |
|
| 932 | if ((flags & KEXEC_FLAGS) != (flags & ~KEXEC_ARCH_MASK))
|
| 933 | return -EINVAL;
|
| 934 |
|
| 935 |
|
| 936 | if (((flags & KEXEC_ARCH_MASK) != KEXEC_ARCH) &&
|
| 937 | ((flags & KEXEC_ARCH_MASK) != KEXEC_ARCH_DEFAULT))
|
| 938 | return -EINVAL;
|
| 939 |
|
| 940 | |
| 941 | * of segments passed to kexec_load.
|
| 942 |
|
| 943 | if (nr_segments > KEXEC_SEGMENT_MAX)
|
| 944 | return -EINVAL;
|
| 945 |
|
| 946 | image = NULL;
|
| 947 | result = 0;
|
| 948 |
|
| 949 | |
| 950 | * region when loading crash kernels we need a mutex here to
|
| 951 | * prevent multiple crash kernels from attempting to load
|
| 952 | * simultaneously, and to prevent a crash kernel from loading
|
| 953 | * over the top of a in use crash kernel.
|
| 954 | *
|
| 955 | * KISS: always take the mutex.
|
| 956 |
|
| 957 | locked = xchg(&kexec_lock, 1);
|
| 958 | if (locked)
|
| 959 | return -EBUSY;
|
| 960 |
|
| 961 | dest_image = &kexec_image;
|
| 962 | if (flags & KEXEC_ON_CRASH)
|
| 963 | dest_image = &kexec_crash_image;
|
| 964 | if (nr_segments > 0) {
|
| 965 | unsigned long i;
|
| 966 |
|
| 967 |
|
| 968 | if ((flags & KEXEC_ON_CRASH) == 0)
|
| 969 | result = kimage_normal_alloc(&image, entry,
|
| 970 | nr_segments, segments);
|
| 971 |
|
| 972 | else if (flags & KEXEC_ON_CRASH) {
|
| 973 | |
| 974 | * we corrupt it.
|
| 975 |
|
| 976 | kimage_free(xchg(&kexec_crash_image, NULL));
|
| 977 | result = kimage_crash_alloc(&image, entry,
|
| 978 | nr_segments, segments);
|
| 979 | }
|
| 980 | if (result)
|
| 981 | goto out;
|
| 982 |
|
| 983 | result = machine_kexec_prepare(image);
|
| 984 | if (result)
|
| 985 | goto out;
|
| 986 |
|
| 987 | for (i = 0; i < nr_segments; i++) {
|
| 988 | result = kimage_load_segment(image, &image->segment[i]);
|
| 989 | if (result)
|
| 990 | goto out;
|
| 991 | }
|
| 992 | result = kimage_terminate(image);
|
| 993 | if (result)
|
| 994 | goto out;
|
| 995 | }
|
| 996 |
|
| 997 | image = xchg(dest_image, image);
|
| 998 |
|
| 999 | out:
|
| 1000 | locked = xchg(&kexec_lock, 0);
|
| 1001 | BUG_ON(!locked);
|
| 1002 | kimage_free(image);
|
| 1003 |
|
| 1004 | return result;
|
| 1005 | }
|
| 1006 |
|
| 1007 | #ifdef CONFIG_COMPAT
|
| 1008 | asmlinkage long compat_sys_kexec_load(unsigned long entry,
|
| 1009 | unsigned long nr_segments,
|
| 1010 | struct compat_kexec_segment __user *segments,
|
| 1011 | unsigned long flags)
|
| 1012 | {
|
| 1013 | struct compat_kexec_segment in;
|
| 1014 | struct kexec_segment out, __user *ksegments;
|
| 1015 | unsigned long i, result;
|
| 1016 |
|
| 1017 | |
| 1018 | * architecture to do anything.
|
| 1019 |
|
| 1020 | if ((flags & KEXEC_ARCH_MASK) == KEXEC_ARCH_DEFAULT)
|
| 1021 | return -EINVAL;
|
| 1022 |
|
| 1023 | if (nr_segments > KEXEC_SEGMENT_MAX)
|
| 1024 | return -EINVAL;
|
| 1025 |
|
| 1026 | ksegments = compat_alloc_user_space(nr_segments * sizeof(out));
|
| 1027 | for (i=0; i < nr_segments; i++) {
|
| 1028 | result = copy_from_user(&in, &segments[i], sizeof(in));
|
| 1029 | if (result)
|
| 1030 | return -EFAULT;
|
| 1031 |
|
| 1032 | out.buf = compat_ptr(in.buf);
|
| 1033 | out.bufsz = in.bufsz;
|
| 1034 | out.mem = in.mem;
|
| 1035 | out.memsz = in.memsz;
|
| 1036 |
|
| 1037 | result = copy_to_user(&ksegments[i], &out, sizeof(out));
|
| 1038 | if (result)
|
| 1039 | return -EFAULT;
|
| 1040 | }
|
| 1041 |
|
| 1042 | return sys_kexec_load(entry, nr_segments, ksegments, flags);
|
| 1043 | }
|
| 1044 | #endif
|
| 1045 |
|
| 1046 | void crash_kexec(struct pt_regs *regs)
|
| 1047 | {
|
| 1048 | int locked;
|
| 1049 |
|
| 1050 |
|
| 1051 | |
| 1052 | * running on one cpu from replacing the crash kernel
|
| 1053 | * we are using after a panic on a different cpu.
|
| 1054 | *
|
| 1055 | * If the crash kernel was not located in a fixed area
|
| 1056 | * of memory the xchg(&kexec_crash_image) would be
|
| 1057 | * sufficient. But since I reuse the memory...
|
| 1058 |
|
| 1059 | locked = xchg(&kexec_lock, 1);
|
| 1060 | if (!locked) {
|
| 1061 | if (kexec_crash_image) {
|
| 1062 | struct pt_regs fixed_regs;
|
| 1063 | crash_setup_regs(&fixed_regs, regs);
|
| 1064 | machine_crash_shutdown(&fixed_regs);
|
| 1065 | machine_kexec(kexec_crash_image);
|
| 1066 | }
|
| 1067 | locked = xchg(&kexec_lock, 0);
|
| 1068 | BUG_ON(!locked);
|
| 1069 | }
|
| 1070 | }
|
| 1071 |
|
| 1072 | static u32 *append_elf_note(u32 *buf, char *name, unsigned type, void *data,
|
| 1073 | size_t data_len)
|
| 1074 | {
|
| 1075 | struct elf_note note;
|
| 1076 |
|
| 1077 | note.n_namesz = strlen(name) + 1;
|
| 1078 | note.n_descsz = data_len;
|
| 1079 | note.n_type = type;
|
| 1080 | memcpy(buf, ¬e, sizeof(note));
|
| 1081 | buf += (sizeof(note) + 3)/4;
|
| 1082 | memcpy(buf, name, note.n_namesz);
|
| 1083 | buf += (note.n_namesz + 3)/4;
|
| 1084 | memcpy(buf, data, note.n_descsz);
|
| 1085 | buf += (note.n_descsz + 3)/4;
|
| 1086 |
|
| 1087 | return buf;
|
| 1088 | }
|
| 1089 |
|
| 1090 | static void final_note(u32 *buf)
|
| 1091 | {
|
| 1092 | struct elf_note note;
|
| 1093 |
|
| 1094 | note.n_namesz = 0;
|
| 1095 | note.n_descsz = 0;
|
| 1096 | note.n_type = 0;
|
| 1097 | memcpy(buf, ¬e, sizeof(note));
|
| 1098 | }
|
| 1099 |
|
| 1100 | void crash_save_cpu(struct pt_regs *regs, int cpu)
|
| 1101 | {
|
| 1102 | struct elf_prstatus prstatus;
|
| 1103 | u32 *buf;
|
| 1104 |
|
| 1105 | if ((cpu < 0) || (cpu >= NR_CPUS))
|
| 1106 | return;
|
| 1107 |
|
| 1108 | |
| 1109 | * I need a well defined structure format
|
| 1110 | * for the data I pass, and I need tags
|
| 1111 | * on the data to indicate what information I have
|
| 1112 | * squirrelled away. ELF notes happen to provide
|
| 1113 | * all of that, so there is no need to invent something new.
|
| 1114 |
|
| 1115 | buf = (u32*)per_cpu_ptr(crash_notes, cpu);
|
| 1116 | if (!buf)
|
| 1117 | return;
|
| 1118 | memset(&prstatus, 0, sizeof(prstatus));
|
| 1119 | prstatus.pr_pid = current->pid;
|
| 1120 | elf_core_copy_regs(&prstatus.pr_reg, regs);
|
| 1121 | buf = append_elf_note(buf, "CORE", NT_PRSTATUS, &prstatus,
|
| 1122 | sizeof(prstatus));
|
| 1123 | final_note(buf);
|
| 1124 | }
|
| 1125 |
|
| 1126 | static int __init crash_notes_memory_init(void)
|
| 1127 | {
|
| 1128 |
|
| 1129 | crash_notes = alloc_percpu(note_buf_t);
|
| 1130 | if (!crash_notes) {
|
| 1131 | printk("Kexec: Memory allocation for saving cpu register"
|
| 1132 | " states failed\n");
|
| 1133 | return -ENOMEM;
|
| 1134 | }
|
| 1135 | return 0;
|
| 1136 | }
|
| 1137 | module_init(crash_notes_memory_init)
|