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Root/kernel/kexec.c

1	/*
2	* kexec.c - kexec system call
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
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/mutex.h>
16	#include <linux/list.h>
17	#include <linux/highmem.h>
18	#include <linux/syscalls.h>
19	#include <linux/reboot.h>
20	#include <linux/ioport.h>
21	#include <linux/hardirq.h>
22	#include <linux/elf.h>
23	#include <linux/elfcore.h>
24	#include <linux/utsrelease.h>
25	#include <linux/utsname.h>
26	#include <linux/numa.h>
27	#include <linux/suspend.h>
28	#include <linux/device.h>
29	#include <linux/freezer.h>
30	#include <linux/pm.h>
31	#include <linux/cpu.h>
32	#include <linux/console.h>
33	#include <linux/vmalloc.h>
34
35	#include <asm/page.h>
36	#include <asm/uaccess.h>
37	#include <asm/io.h>
38	#include <asm/system.h>
39	#include <asm/sections.h>
40
41	/* Per cpu memory for storing cpu states in case of system crash. */
42	note_buf_t* crash_notes;
43
44	/* vmcoreinfo stuff */
45	static unsigned char vmcoreinfo_data[VMCOREINFO_BYTES];
46	u32 vmcoreinfo_note[VMCOREINFO_NOTE_SIZE/4];
47	size_t vmcoreinfo_size;
48	size_t vmcoreinfo_max_size = sizeof(vmcoreinfo_data);
49
50	/* Location of the reserved area for the crash kernel */
51	struct resource crashk_res = {
52	.name = "Crash kernel",
53	.start = 0,
54	.end = 0,
55	.flags = IORESOURCE_BUSY \| IORESOURCE_MEM
56	};
57
58	int kexec_should_crash(struct task_struct *p)
59	{
60	if (in_interrupt() \|\| !p->pid \|\| is_global_init(p) \|\| panic_on_oops)
61	return 1;
62	return 0;
63	}
64
65	/*
66	* When kexec transitions to the new kernel there is a one-to-one
67	* mapping between physical and virtual addresses. On processors
68	* where you can disable the MMU this is trivial, and easy. For
69	* others it is still a simple predictable page table to setup.
70	*
71	* In that environment kexec copies the new kernel to its final
72	* resting place. This means I can only support memory whose
73	* physical address can fit in an unsigned long. In particular
74	* addresses where (pfn << PAGE_SHIFT) > ULONG_MAX cannot be handled.
75	* If the assembly stub has more restrictive requirements
76	* KEXEC_SOURCE_MEMORY_LIMIT and KEXEC_DEST_MEMORY_LIMIT can be
77	* defined more restrictively in <asm/kexec.h>.
78	*
79	* The code for the transition from the current kernel to the
80	* the new kernel is placed in the control_code_buffer, whose size
81	* is given by KEXEC_CONTROL_PAGE_SIZE. In the best case only a single
82	* page of memory is necessary, but some architectures require more.
83	* Because this memory must be identity mapped in the transition from
84	* virtual to physical addresses it must live in the range
85	* 0 - TASK_SIZE, as only the user space mappings are arbitrarily
86	* modifiable.
87	*
88	* The assembly stub in the control code buffer is passed a linked list
89	* of descriptor pages detailing the source pages of the new kernel,
90	* and the destination addresses of those source pages. As this data
91	* structure is not used in the context of the current OS, it must
92	* be self-contained.
93	*
94	* The code has been made to work with highmem pages and will use a
95	* destination page in its final resting place (if it happens
96	* to allocate it). The end product of this is that most of the
97	* physical address space, and most of RAM can be used.
98	*
99	* Future directions include:
100	* - allocating a page table with the control code buffer identity
101	* mapped, to simplify machine_kexec and make kexec_on_panic more
102	* reliable.
103	*/
104
105	/*
106	* KIMAGE_NO_DEST is an impossible destination address..., for
107	* allocating pages whose destination address we do not care about.
108	*/
109	#define KIMAGE_NO_DEST (-1UL)
110
111	static int kimage_is_destination_range(struct kimage *image,
112	unsigned long start, unsigned long end);
113	static struct page kimage_alloc_page(struct kimage image,
114	gfp_t gfp_mask,
115	unsigned long dest);
116
117	static int do_kimage_alloc(struct kimage **rimage, unsigned long entry,
118	unsigned long nr_segments,
119	struct kexec_segment __user *segments)
120	{
121	size_t segment_bytes;
122	struct kimage *image;
123	unsigned long i;
124	int result;
125
126	/* Allocate a controlling structure */
127	result = -ENOMEM;
128	image = kzalloc(sizeof(*image), GFP_KERNEL);
129	if (!image)
130	goto out;
131
132	image->head = 0;
133	image->entry = &image->head;
134	image->last_entry = &image->head;
135	image->control_page = ~0; /* By default this does not apply */
136	image->start = entry;
137	image->type = KEXEC_TYPE_DEFAULT;
138
139	/* Initialize the list of control pages */
140	INIT_LIST_HEAD(&image->control_pages);
141
142	/* Initialize the list of destination pages */
143	INIT_LIST_HEAD(&image->dest_pages);
144
145	/* Initialize the list of unuseable pages */
146	INIT_LIST_HEAD(&image->unuseable_pages);
147
148	/* Read in the segments */
149	image->nr_segments = nr_segments;
150	segment_bytes = nr_segments * sizeof(*segments);
151	result = copy_from_user(image->segment, segments, segment_bytes);
152	if (result)
153	goto out;
154
155	/*
156	* Verify we have good destination addresses. The caller is
157	* responsible for making certain we don't attempt to load
158	* the new image into invalid or reserved areas of RAM. This
159	* just verifies it is an address we can use.
160	*
161	* Since the kernel does everything in page size chunks ensure
162	* the destination addreses are page aligned. Too many
163	* special cases crop of when we don't do this. The most
164	* insidious is getting overlapping destination addresses
165	* simply because addresses are changed to page size
166	* granularity.
167	*/
168	result = -EADDRNOTAVAIL;
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;
174	if ((mstart & ~PAGE_MASK) \|\| (mend & ~PAGE_MASK))
175	goto out;
176	if (mend >= KEXEC_DESTINATION_MEMORY_LIMIT)
177	goto out;
178	}
179
180	/* Verify our destination addresses do not overlap.
181	* If we alloed overlapping destination addresses
182	* through very weird things can happen with no
183	* easy explanation as one segment stops on another.
184	*/
185	result = -EINVAL;
186	for (i = 0; i < nr_segments; i++) {
187	unsigned long mstart, mend;
188	unsigned long j;
189
190	mstart = image->segment[i].mem;
191	mend = mstart + image->segment[i].memsz;
192	for (j = 0; j < i; j++) {
193	unsigned long pstart, pend;
194	pstart = image->segment[j].mem;
195	pend = pstart + image->segment[j].memsz;
196	/* Do the segments overlap ? */
197	if ((mend > pstart) && (mstart < pend))
198	goto out;
199	}
200	}
201
202	/* Ensure our buffer sizes are strictly less than
203	* our memory sizes. This should always be the case,
204	* and it is easier to check up front than to be surprised
205	* later on.
206	*/
207	result = -EINVAL;
208	for (i = 0; i < nr_segments; i++) {
209	if (image->segment[i].bufsz > image->segment[i].memsz)
210	goto out;
211	}
212
213	result = 0;
214	out:
215	if (result == 0)
216	*rimage = image;
217	else
218	kfree(image);
219
220	return result;
221
222	}
223
224	static int kimage_normal_alloc(struct kimage **rimage, unsigned long entry,
225	unsigned long nr_segments,
226	struct kexec_segment __user *segments)
227	{
228	int result;
229	struct kimage *image;
230
231	/* Allocate and initialize a controlling structure */
232	image = NULL;
233	result = do_kimage_alloc(&image, entry, nr_segments, segments);
234	if (result)
235	goto out;
236
237	*rimage = image;
238
239	/*
240	* Find a location for the control code buffer, and add it
241	* the vector of segments so that it's pages will also be
242	* counted as destination pages.
243	*/
244	result = -ENOMEM;
245	image->control_code_page = kimage_alloc_control_pages(image,
246	get_order(KEXEC_CONTROL_PAGE_SIZE));
247	if (!image->control_code_page) {
248	printk(KERN_ERR "Could not allocate control_code_buffer\n");
249	goto out;
250	}
251
252	image->swap_page = kimage_alloc_control_pages(image, 0);
253	if (!image->swap_page) {
254	printk(KERN_ERR "Could not allocate swap buffer\n");
255	goto out;
256	}
257
258	result = 0;
259	out:
260	if (result == 0)
261	*rimage = image;
262	else
263	kfree(image);
264
265	return result;
266	}
267
268	static int kimage_crash_alloc(struct kimage **rimage, unsigned long entry,
269	unsigned long nr_segments,
270	struct kexec_segment __user *segments)
271	{
272	int result;
273	struct kimage *image;
274	unsigned long i;
275
276	image = NULL;
277	/* Verify we have a valid entry point */
278	if ((entry < crashk_res.start) \|\| (entry > crashk_res.end)) {
279	result = -EADDRNOTAVAIL;
280	goto out;
281	}
282
283	/* Allocate and initialize a controlling structure */
284	result = do_kimage_alloc(&image, entry, nr_segments, segments);
285	if (result)
286	goto out;
287
288	/* Enable the special crash kernel control page
289	* allocation policy.
290	*/
291	image->control_page = crashk_res.start;
292	image->type = KEXEC_TYPE_CRASH;
293
294	/*
295	* Verify we have good destination addresses. Normally
296	* the caller is responsible for making certain we don't
297	* attempt to load the new image into invalid or reserved
298	* areas of RAM. But crash kernels are preloaded into a
299	* reserved area of ram. We must ensure the addresses
300	* are in the reserved area otherwise preloading the
301	* kernel could corrupt things.
302	*/
303	result = -EADDRNOTAVAIL;
304	for (i = 0; i < nr_segments; i++) {
305	unsigned long mstart, mend;
306
307	mstart = image->segment[i].mem;
308	mend = mstart + image->segment[i].memsz - 1;
309	/* Ensure we are within the crash kernel limits */
310	if ((mstart < crashk_res.start) \|\| (mend > crashk_res.end))
311	goto out;
312	}
313
314	/*
315	* Find a location for the control code buffer, and add
316	* the vector of segments so that it's pages will also be
317	* counted as destination pages.
318	*/
319	result = -ENOMEM;
320	image->control_code_page = kimage_alloc_control_pages(image,
321	get_order(KEXEC_CONTROL_PAGE_SIZE));
322	if (!image->control_code_page) {
323	printk(KERN_ERR "Could not allocate control_code_buffer\n");
324	goto out;
325	}
326
327	result = 0;
328	out:
329	if (result == 0)
330	*rimage = image;
331	else
332	kfree(image);
333
334	return result;
335	}
336
337	static int kimage_is_destination_range(struct kimage *image,
338	unsigned long start,
339	unsigned long end)
340	{
341	unsigned long i;
342
343	for (i = 0; i < image->nr_segments; i++) {
344	unsigned long mstart, mend;
345
346	mstart = image->segment[i].mem;
347	mend = mstart + image->segment[i].memsz;
348	if ((end > mstart) && (start < mend))
349	return 1;
350	}
351
352	return 0;
353	}
354
355	static struct page *kimage_alloc_pages(gfp_t gfp_mask, unsigned int order)
356	{
357	struct page *pages;
358
359	pages = alloc_pages(gfp_mask, order);
360	if (pages) {
361	unsigned int count, i;
362	pages->mapping = NULL;
363	set_page_private(pages, order);
364	count = 1 << order;
365	for (i = 0; i < count; i++)
366	SetPageReserved(pages + i);
367	}
368
369	return pages;
370	}
371
372	static void kimage_free_pages(struct page *page)
373	{
374	unsigned int order, count, i;
375
376	order = page_private(page);
377	count = 1 << order;
378	for (i = 0; i < count; i++)
379	ClearPageReserved(page + i);
380	__free_pages(page, order);
381	}
382
383	static void kimage_free_page_list(struct list_head *list)
384	{
385	struct list_head pos, next;
386
387	list_for_each_safe(pos, next, list) {
388	struct page *page;
389
390	page = list_entry(pos, struct page, lru);
391	list_del(&page->lru);
392	kimage_free_pages(page);
393	}
394	}
395
396	static struct page kimage_alloc_normal_control_pages(struct kimage image,
397	unsigned int order)
398	{
399	/* Control pages are special, they are the intermediaries
400	* that are needed while we copy the rest of the pages
401	* to their final resting place. As such they must
402	* not conflict with either the destination addresses
403	* or memory the kernel is already using.
404	*
405	* The only case where we really need more than one of
406	* these are for architectures where we cannot disable
407	* the MMU and must instead generate an identity mapped
408	* page table for all of the memory.
409	*
410	* At worst this runs in O(N) of the image size.
411	*/
412	struct list_head extra_pages;
413	struct page *pages;
414	unsigned int count;
415
416	count = 1 << order;
417	INIT_LIST_HEAD(&extra_pages);
418
419	/* Loop while I can allocate a page and the page allocated
420	* is a destination page.
421	*/
422	do {
423	unsigned long pfn, epfn, addr, eaddr;
424
425	pages = kimage_alloc_pages(GFP_KERNEL, order);
426	if (!pages)
427	break;
428	pfn = page_to_pfn(pages);
429	epfn = pfn + count;
430	addr = pfn << PAGE_SHIFT;
431	eaddr = epfn << PAGE_SHIFT;
432	if ((epfn >= (KEXEC_CONTROL_MEMORY_LIMIT >> PAGE_SHIFT)) \|\|
433	kimage_is_destination_range(image, addr, eaddr)) {
434	list_add(&pages->lru, &extra_pages);
435	pages = NULL;
436	}
437	} while (!pages);
438
439	if (pages) {
440	/* Remember the allocated page... */
441	list_add(&pages->lru, &image->control_pages);
442
443	/* Because the page is already in it's destination
444	* location we will never allocate another page at
445	* that address. Therefore kimage_alloc_pages
446	* will not return it (again) and we don't need
447	* to give it an entry in image->segment[].
448	*/
449	}
450	/* Deal with the destination pages I have inadvertently allocated.
451	*
452	* Ideally I would convert multi-page allocations into single
453	* page allocations, and add everyting to image->dest_pages.
454	*
455	* For now it is simpler to just free the pages.
456	*/
457	kimage_free_page_list(&extra_pages);
458
459	return pages;
460	}
461
462	static struct page kimage_alloc_crash_control_pages(struct kimage image,
463	unsigned int order)
464	{
465	/* Control pages are special, they are the intermediaries
466	* that are needed while we copy the rest of the pages
467	* to their final resting place. As such they must
468	* not conflict with either the destination addresses
469	* or memory the kernel is already using.
470	*
471	* Control pages are also the only pags we must allocate
472	* when loading a crash kernel. All of the other pages
473	* are specified by the segments and we just memcpy
474	* into them directly.
475	*
476	* The only case where we really need more than one of
477	* these are for architectures where we cannot disable
478	* the MMU and must instead generate an identity mapped
479	* page table for all of the memory.
480	*
481	* Given the low demand this implements a very simple
482	* allocator that finds the first hole of the appropriate
483	* size in the reserved memory region, and allocates all
484	* of the memory up to and including the hole.
485	*/
486	unsigned long hole_start, hole_end, size;
487	struct page *pages;
488
489	pages = NULL;
490	size = (1 << order) << PAGE_SHIFT;
491	hole_start = (image->control_page + (size - 1)) & ~(size - 1);
492	hole_end = hole_start + size - 1;
493	while (hole_end <= crashk_res.end) {
494	unsigned long i;
495
496	if (hole_end > KEXEC_CONTROL_MEMORY_LIMIT)
497	break;
498	if (hole_end > crashk_res.end)
499	break;
500	/* See if I overlap any of the segments */
501	for (i = 0; i < image->nr_segments; i++) {
502	unsigned long mstart, mend;
503
504	mstart = image->segment[i].mem;
505	mend = mstart + image->segment[i].memsz - 1;
506	if ((hole_end >= mstart) && (hole_start <= mend)) {
507	/* Advance the hole to the end of the segment */
508	hole_start = (mend + (size - 1)) & ~(size - 1);
509	hole_end = hole_start + size - 1;
510	break;
511	}
512	}
513	/* If I don't overlap any segments I have found my hole! */
514	if (i == image->nr_segments) {
515	pages = pfn_to_page(hole_start >> PAGE_SHIFT);
516	break;
517	}
518	}
519	if (pages)
520	image->control_page = hole_end;
521
522	return pages;
523	}
524
525
526	struct page kimage_alloc_control_pages(struct kimage image,
527	unsigned int order)
528	{
529	struct page *pages = NULL;
530
531	switch (image->type) {
532	case KEXEC_TYPE_DEFAULT:
533	pages = kimage_alloc_normal_control_pages(image, order);
534	break;
535	case KEXEC_TYPE_CRASH:
536	pages = kimage_alloc_crash_control_pages(image, order);
537	break;
538	}
539
540	return pages;
541	}
542
543	static int kimage_add_entry(struct kimage *image, kimage_entry_t entry)
544	{
545	if (*image->entry != 0)
546	image->entry++;
547
548	if (image->entry == image->last_entry) {
549	kimage_entry_t *ind_page;
550	struct page *page;
551
552	page = kimage_alloc_page(image, GFP_KERNEL, KIMAGE_NO_DEST);
553	if (!page)
554	return -ENOMEM;
555
556	ind_page = page_address(page);
557	*image->entry = virt_to_phys(ind_page) \| IND_INDIRECTION;
558	image->entry = ind_page;
559	image->last_entry = ind_page +
560	((PAGE_SIZE/sizeof(kimage_entry_t)) - 1);
561	}
562	*image->entry = entry;
563	image->entry++;
564	*image->entry = 0;
565
566	return 0;
567	}
568
569	static int kimage_set_destination(struct kimage *image,
570	unsigned long destination)
571	{
572	int result;
573
574	destination &= PAGE_MASK;
575	result = kimage_add_entry(image, destination \| IND_DESTINATION);
576	if (result == 0)
577	image->destination = destination;
578
579	return result;
580	}
581
582
583	static int kimage_add_page(struct kimage *image, unsigned long page)
584	{
585	int result;
586
587	page &= PAGE_MASK;
588	result = kimage_add_entry(image, page \| IND_SOURCE);
589	if (result == 0)
590	image->destination += PAGE_SIZE;
591
592	return result;
593	}
594
595
596	static void kimage_free_extra_pages(struct kimage *image)
597	{
598	/* Walk through and free any extra destination pages I may have */
599	kimage_free_page_list(&image->dest_pages);
600
601	/* Walk through and free any unuseable pages I have cached */
602	kimage_free_page_list(&image->unuseable_pages);
603
604	}
605	static void kimage_terminate(struct kimage *image)
606	{
607	if (*image->entry != 0)
608	image->entry++;
609
610	*image->entry = IND_DONE;
611	}
612
613	#define for_each_kimage_entry(image, ptr, entry) \
614	for (ptr = &image->head; (entry = *ptr) && !(entry & IND_DONE); \
615	ptr = (entry & IND_INDIRECTION)? \
616	phys_to_virt((entry & PAGE_MASK)): ptr +1)
617
618	static void kimage_free_entry(kimage_entry_t entry)
619	{
620	struct page *page;
621
622	page = pfn_to_page(entry >> PAGE_SHIFT);
623	kimage_free_pages(page);
624	}
625
626	static void kimage_free(struct kimage *image)
627	{
628	kimage_entry_t *ptr, entry;
629	kimage_entry_t ind = 0;
630
631	if (!image)
632	return;
633
634	kimage_free_extra_pages(image);
635	for_each_kimage_entry(image, ptr, entry) {
636	if (entry & IND_INDIRECTION) {
637	/* Free the previous indirection page */
638	if (ind & IND_INDIRECTION)
639	kimage_free_entry(ind);
640	/* Save this indirection page until we are
641	* done with it.
642	*/
643	ind = entry;
644	}
645	else if (entry & IND_SOURCE)
646	kimage_free_entry(entry);
647	}
648	/* Free the final indirection page */
649	if (ind & IND_INDIRECTION)
650	kimage_free_entry(ind);
651
652	/* Handle any machine specific cleanup */
653	machine_kexec_cleanup(image);
654
655	/* Free the kexec control pages... */
656	kimage_free_page_list(&image->control_pages);
657	kfree(image);
658	}
659
660	static kimage_entry_t kimage_dst_used(struct kimage image,
661	unsigned long page)
662	{
663	kimage_entry_t *ptr, entry;
664	unsigned long destination = 0;
665
666	for_each_kimage_entry(image, ptr, entry) {
667	if (entry & IND_DESTINATION)
668	destination = entry & PAGE_MASK;
669	else if (entry & IND_SOURCE) {
670	if (page == destination)
671	return ptr;
672	destination += PAGE_SIZE;
673	}
674	}
675
676	return NULL;
677	}
678
679	static struct page kimage_alloc_page(struct kimage image,
680	gfp_t gfp_mask,
681	unsigned long destination)
682	{
683	/*
684	* Here we implement safeguards to ensure that a source page
685	* is not copied to its destination page before the data on
686	* the destination page is no longer useful.
687	*
688	* To do this we maintain the invariant that a source page is
689	* either its own destination page, or it is not a
690	* destination page at all.
691	*
692	* That is slightly stronger than required, but the proof
693	* that no problems will not occur is trivial, and the
694	* implementation is simply to verify.
695	*
696	* When allocating all pages normally this algorithm will run
697	* in O(N) time, but in the worst case it will run in O(N^2)
698	* time. If the runtime is a problem the data structures can
699	* be fixed.
700	*/
701	struct page *page;
702	unsigned long addr;
703
704	/*
705	* Walk through the list of destination pages, and see if I
706	* have a match.
707	*/
708	list_for_each_entry(page, &image->dest_pages, lru) {
709	addr = page_to_pfn(page) << PAGE_SHIFT;
710	if (addr == destination) {
711	list_del(&page->lru);
712	return page;
713	}
714	}
715	page = NULL;
716	while (1) {
717	kimage_entry_t *old;
718
719	/* Allocate a page, if we run out of memory give up */
720	page = kimage_alloc_pages(gfp_mask, 0);
721	if (!page)
722	return NULL;
723	/* If the page cannot be used file it away */
724	if (page_to_pfn(page) >
725	(KEXEC_SOURCE_MEMORY_LIMIT >> PAGE_SHIFT)) {
726	list_add(&page->lru, &image->unuseable_pages);
727	continue;
728	}
729	addr = page_to_pfn(page) << PAGE_SHIFT;
730
731	/* If it is the destination page we want use it */
732	if (addr == destination)
733	break;
734
735	/* If the page is not a destination page use it */
736	if (!kimage_is_destination_range(image, addr,
737	addr + PAGE_SIZE))
738	break;
739
740	/*
741	* I know that the page is someones destination page.
742	* See if there is already a source page for this
743	* destination page. And if so swap the source pages.
744	*/
745	old = kimage_dst_used(image, addr);
746	if (old) {
747	/* If so move it */
748	unsigned long old_addr;
749	struct page *old_page;
750
751	old_addr = *old & PAGE_MASK;
752	old_page = pfn_to_page(old_addr >> PAGE_SHIFT);
753	copy_highpage(page, old_page);
754	old = addr \| (old & ~PAGE_MASK);
755
756	/* The old page I have found cannot be a
757	* destination page, so return it if it's
758	* gfp_flags honor the ones passed in.
759	*/
760	if (!(gfp_mask & __GFP_HIGHMEM) &&
761	PageHighMem(old_page)) {
762	kimage_free_pages(old_page);
763	continue;
764	}
765	addr = old_addr;
766	page = old_page;
767	break;
768	}
769	else {
770	/* Place the page on the destination list I
771	* will use it later.
772	*/
773	list_add(&page->lru, &image->dest_pages);
774	}
775	}
776
777	return page;
778	}
779
780	static int kimage_load_normal_segment(struct kimage *image,
781	struct kexec_segment *segment)
782	{
783	unsigned long maddr;
784	unsigned long ubytes, mbytes;
785	int result;
786	unsigned char __user *buf;
787
788	result = 0;
789	buf = segment->buf;
790	ubytes = segment->bufsz;
791	mbytes = segment->memsz;
792	maddr = segment->mem;
793
794	result = kimage_set_destination(image, maddr);
795	if (result < 0)
796	goto out;
797
798	while (mbytes) {
799	struct page *page;
800	char *ptr;
801	size_t uchunk, mchunk;
802
803	page = kimage_alloc_page(image, GFP_HIGHUSER, maddr);
804	if (!page) {
805	result = -ENOMEM;
806	goto out;
807	}
808	result = kimage_add_page(image, page_to_pfn(page)
809	<< PAGE_SHIFT);
810	if (result < 0)
811	goto out;
812
813	ptr = kmap(page);
814	/* Start with a clear page */
815	memset(ptr, 0, PAGE_SIZE);
816	ptr += maddr & ~PAGE_MASK;
817	mchunk = PAGE_SIZE - (maddr & ~PAGE_MASK);
818	if (mchunk > mbytes)
819	mchunk = mbytes;
820
821	uchunk = mchunk;
822	if (uchunk > ubytes)
823	uchunk = ubytes;
824
825	result = copy_from_user(ptr, buf, uchunk);
826	kunmap(page);
827	if (result) {
828	result = (result < 0) ? result : -EIO;
829	goto out;
830	}
831	ubytes -= uchunk;
832	maddr += mchunk;
833	buf += mchunk;
834	mbytes -= mchunk;
835	}
836	out:
837	return result;
838	}
839
840	static int kimage_load_crash_segment(struct kimage *image,
841	struct kexec_segment *segment)
842	{
843	/* For crash dumps kernels we simply copy the data from
844	* user space to it's destination.
845	* We do things a page at a time for the sake of kmap.
846	*/
847	unsigned long maddr;
848	unsigned long ubytes, mbytes;
849	int result;
850	unsigned char __user *buf;
851
852	result = 0;
853	buf = segment->buf;
854	ubytes = segment->bufsz;
855	mbytes = segment->memsz;
856	maddr = segment->mem;
857	while (mbytes) {
858	struct page *page;
859	char *ptr;
860	size_t uchunk, mchunk;
861
862	page = pfn_to_page(maddr >> PAGE_SHIFT);
863	if (!page) {
864	result = -ENOMEM;
865	goto out;
866	}
867	ptr = kmap(page);
868	ptr += maddr & ~PAGE_MASK;
869	mchunk = PAGE_SIZE - (maddr & ~PAGE_MASK);
870	if (mchunk > mbytes)
871	mchunk = mbytes;
872
873	uchunk = mchunk;
874	if (uchunk > ubytes) {
875	uchunk = ubytes;
876	/* Zero the trailing part of the page */
877	memset(ptr + uchunk, 0, mchunk - uchunk);
878	}
879	result = copy_from_user(ptr, buf, uchunk);
880	kexec_flush_icache_page(page);
881	kunmap(page);
882	if (result) {
883	result = (result < 0) ? result : -EIO;
884	goto out;
885	}
886	ubytes -= uchunk;
887	maddr += mchunk;
888	buf += mchunk;
889	mbytes -= mchunk;
890	}
891	out:
892	return result;
893	}
894
895	static int kimage_load_segment(struct kimage *image,
896	struct kexec_segment *segment)
897	{
898	int result = -ENOMEM;
899
900	switch (image->type) {
901	case KEXEC_TYPE_DEFAULT:
902	result = kimage_load_normal_segment(image, segment);
903	break;
904	case KEXEC_TYPE_CRASH:
905	result = kimage_load_crash_segment(image, segment);
906	break;
907	}
908
909	return result;
910	}
911
912	/*
913	* Exec Kernel system call: for obvious reasons only root may call it.
914	*
915	* This call breaks up into three pieces.
916	* - A generic part which loads the new kernel from the current
917	* address space, and very carefully places the data in the
918	* allocated pages.
919	*
920	* - A generic part that interacts with the kernel and tells all of
921	* the devices to shut down. Preventing on-going dmas, and placing
922	* the devices in a consistent state so a later kernel can
923	* reinitialize them.
924	*
925	* - A machine specific part that includes the syscall number
926	* and the copies the image to it's final destination. And
927	* jumps into the image at entry.
928	*
929	* kexec does not sync, or unmount filesystems so if you need
930	* that to happen you need to do that yourself.
931	*/
932	struct kimage *kexec_image;
933	struct kimage *kexec_crash_image;
934
935	static DEFINE_MUTEX(kexec_mutex);
936
937	SYSCALL_DEFINE4(kexec_load, unsigned long, entry, unsigned long, nr_segments,
938	struct kexec_segment __user *, segments, unsigned long, flags)
939	{
940	struct kimage *dest_image, image;
941	int result;
942
943	/* We only trust the superuser with rebooting the system. */
944	if (!capable(CAP_SYS_BOOT))
945	return -EPERM;
946
947	/*
948	* Verify we have a legal set of flags
949	* This leaves us room for future extensions.
950	*/
951	if ((flags & KEXEC_FLAGS) != (flags & ~KEXEC_ARCH_MASK))
952	return -EINVAL;
953
954	/* Verify we are on the appropriate architecture */
955	if (((flags & KEXEC_ARCH_MASK) != KEXEC_ARCH) &&
956	((flags & KEXEC_ARCH_MASK) != KEXEC_ARCH_DEFAULT))
957	return -EINVAL;
958
959	/* Put an artificial cap on the number
960	* of segments passed to kexec_load.
961	*/
962	if (nr_segments > KEXEC_SEGMENT_MAX)
963	return -EINVAL;
964
965	image = NULL;
966	result = 0;
967
968	/* Because we write directly to the reserved memory
969	* region when loading crash kernels we need a mutex here to
970	* prevent multiple crash kernels from attempting to load
971	* simultaneously, and to prevent a crash kernel from loading
972	* over the top of a in use crash kernel.
973	*
974	* KISS: always take the mutex.
975	*/
976	if (!mutex_trylock(&kexec_mutex))
977	return -EBUSY;
978
979	dest_image = &kexec_image;
980	if (flags & KEXEC_ON_CRASH)
981	dest_image = &kexec_crash_image;
982	if (nr_segments > 0) {
983	unsigned long i;
984
985	/* Loading another kernel to reboot into */
986	if ((flags & KEXEC_ON_CRASH) == 0)
987	result = kimage_normal_alloc(&image, entry,
988	nr_segments, segments);
989	/* Loading another kernel to switch to if this one crashes */
990	else if (flags & KEXEC_ON_CRASH) {
991	/* Free any current crash dump kernel before
992	* we corrupt it.
993	*/
994	kimage_free(xchg(&kexec_crash_image, NULL));
995	result = kimage_crash_alloc(&image, entry,
996	nr_segments, segments);
997	}
998	if (result)
999	goto out;
1000
1001	if (flags & KEXEC_PRESERVE_CONTEXT)
1002	image->preserve_context = 1;
1003	result = machine_kexec_prepare(image);
1004	if (result)
1005	goto out;
1006
1007	for (i = 0; i < nr_segments; i++) {
1008	result = kimage_load_segment(image, &image->segment[i]);
1009	if (result)
1010	goto out;
1011	}
1012	kimage_terminate(image);
1013	}
1014	/* Install the new kernel, and Uninstall the old */
1015	image = xchg(dest_image, image);
1016
1017	out:
1018	mutex_unlock(&kexec_mutex);
1019	kimage_free(image);
1020
1021	return result;
1022	}
1023
1024	#ifdef CONFIG_COMPAT
1025	asmlinkage long compat_sys_kexec_load(unsigned long entry,
1026	unsigned long nr_segments,
1027	struct compat_kexec_segment __user *segments,
1028	unsigned long flags)
1029	{
1030	struct compat_kexec_segment in;
1031	struct kexec_segment out, __user *ksegments;
1032	unsigned long i, result;
1033
1034	/* Don't allow clients that don't understand the native
1035	* architecture to do anything.
1036	*/
1037	if ((flags & KEXEC_ARCH_MASK) == KEXEC_ARCH_DEFAULT)
1038	return -EINVAL;
1039
1040	if (nr_segments > KEXEC_SEGMENT_MAX)
1041	return -EINVAL;
1042
1043	ksegments = compat_alloc_user_space(nr_segments * sizeof(out));
1044	for (i=0; i < nr_segments; i++) {
1045	result = copy_from_user(&in, &segments[i], sizeof(in));
1046	if (result)
1047	return -EFAULT;
1048
1049	out.buf = compat_ptr(in.buf);
1050	out.bufsz = in.bufsz;
1051	out.mem = in.mem;
1052	out.memsz = in.memsz;
1053
1054	result = copy_to_user(&ksegments[i], &out, sizeof(out));
1055	if (result)
1056	return -EFAULT;
1057	}
1058
1059	return sys_kexec_load(entry, nr_segments, ksegments, flags);
1060	}
1061	#endif
1062
1063	void crash_kexec(struct pt_regs *regs)
1064	{
1065	/* Take the kexec_mutex here to prevent sys_kexec_load
1066	* running on one cpu from replacing the crash kernel
1067	* we are using after a panic on a different cpu.
1068	*
1069	* If the crash kernel was not located in a fixed area
1070	* of memory the xchg(&kexec_crash_image) would be
1071	* sufficient. But since I reuse the memory...
1072	*/
1073	if (mutex_trylock(&kexec_mutex)) {
1074	if (kexec_crash_image) {
1075	struct pt_regs fixed_regs;
1076	crash_setup_regs(&fixed_regs, regs);
1077	crash_save_vmcoreinfo();
1078	machine_crash_shutdown(&fixed_regs);
1079	machine_kexec(kexec_crash_image);
1080	}
1081	mutex_unlock(&kexec_mutex);
1082	}
1083	}
1084
1085	static u32 append_elf_note(u32 buf, char name, unsigned type, void data,
1086	size_t data_len)
1087	{
1088	struct elf_note note;
1089
1090	note.n_namesz = strlen(name) + 1;
1091	note.n_descsz = data_len;
1092	note.n_type = type;
1093	memcpy(buf, &note, sizeof(note));
1094	buf += (sizeof(note) + 3)/4;
1095	memcpy(buf, name, note.n_namesz);
1096	buf += (note.n_namesz + 3)/4;
1097	memcpy(buf, data, note.n_descsz);
1098	buf += (note.n_descsz + 3)/4;
1099
1100	return buf;
1101	}
1102
1103	static void final_note(u32 *buf)
1104	{
1105	struct elf_note note;
1106
1107	note.n_namesz = 0;
1108	note.n_descsz = 0;
1109	note.n_type = 0;
1110	memcpy(buf, &note, sizeof(note));
1111	}
1112
1113	void crash_save_cpu(struct pt_regs *regs, int cpu)
1114	{
1115	struct elf_prstatus prstatus;
1116	u32 *buf;
1117
1118	if ((cpu < 0) \|\| (cpu >= nr_cpu_ids))
1119	return;
1120
1121	/* Using ELF notes here is opportunistic.
1122	* I need a well defined structure format
1123	* for the data I pass, and I need tags
1124	* on the data to indicate what information I have
1125	* squirrelled away. ELF notes happen to provide
1126	* all of that, so there is no need to invent something new.
1127	*/
1128	buf = (u32*)per_cpu_ptr(crash_notes, cpu);
1129	if (!buf)
1130	return;
1131	memset(&prstatus, 0, sizeof(prstatus));
1132	prstatus.pr_pid = current->pid;
1133	elf_core_copy_kernel_regs(&prstatus.pr_reg, regs);
1134	buf = append_elf_note(buf, KEXEC_CORE_NOTE_NAME, NT_PRSTATUS,
1135	&prstatus, sizeof(prstatus));
1136	final_note(buf);
1137	}
1138
1139	static int __init crash_notes_memory_init(void)
1140	{
1141	/* Allocate memory for saving cpu registers. */
1142	crash_notes = alloc_percpu(note_buf_t);
1143	if (!crash_notes) {
1144	printk("Kexec: Memory allocation for saving cpu register"
1145	" states failed\n");
1146	return -ENOMEM;
1147	}
1148	return 0;
1149	}
1150	module_init(crash_notes_memory_init)
1151
1152
1153	/*
1154	* parsing the "crashkernel" commandline
1155	*
1156	* this code is intended to be called from architecture specific code
1157	*/
1158
1159
1160	/*
1161	* This function parses command lines in the format
1162	*
1163	* crashkernel=ramsize-range:size[,...][@offset]
1164	*
1165	* The function returns 0 on success and -EINVAL on failure.
1166	*/
1167	static int __init parse_crashkernel_mem(char *cmdline,
1168	unsigned long long system_ram,
1169	unsigned long long *crash_size,
1170	unsigned long long *crash_base)
1171	{
1172	char cur = cmdline, tmp;
1173
1174	/* for each entry of the comma-separated list */
1175	do {
1176	unsigned long long start, end = ULLONG_MAX, size;
1177
1178	/* get the start of the range */
1179	start = memparse(cur, &tmp);
1180	if (cur == tmp) {
1181	pr_warning("crashkernel: Memory value expected\n");
1182	return -EINVAL;
1183	}
1184	cur = tmp;
1185	if (*cur != '-') {
1186	pr_warning("crashkernel: '-' expected\n");
1187	return -EINVAL;
1188	}
1189	cur++;
1190
1191	/* if no ':' is here, than we read the end */
1192	if (*cur != ':') {
1193	end = memparse(cur, &tmp);
1194	if (cur == tmp) {
1195	pr_warning("crashkernel: Memory "
1196	"value expected\n");
1197	return -EINVAL;
1198	}
1199	cur = tmp;
1200	if (end <= start) {
1201	pr_warning("crashkernel: end <= start\n");
1202	return -EINVAL;
1203	}
1204	}
1205
1206	if (*cur != ':') {
1207	pr_warning("crashkernel: ':' expected\n");
1208	return -EINVAL;
1209	}
1210	cur++;
1211
1212	size = memparse(cur, &tmp);
1213	if (cur == tmp) {
1214	pr_warning("Memory value expected\n");
1215	return -EINVAL;
1216	}
1217	cur = tmp;
1218	if (size >= system_ram) {
1219	pr_warning("crashkernel: invalid size\n");
1220	return -EINVAL;
1221	}
1222
1223	/* match ? */
1224	if (system_ram >= start && system_ram < end) {
1225	*crash_size = size;
1226	break;
1227	}
1228	} while (*cur++ == ',');
1229
1230	if (*crash_size > 0) {
1231	while (cur && cur != ' ' && *cur != '@')
1232	cur++;
1233	if (*cur == '@') {
1234	cur++;
1235	*crash_base = memparse(cur, &tmp);
1236	if (cur == tmp) {
1237	pr_warning("Memory value expected "
1238	"after '@'\n");
1239	return -EINVAL;
1240	}
1241	}
1242	}
1243
1244	return 0;
1245	}
1246
1247	/*
1248	* That function parses "simple" (old) crashkernel command lines like
1249	*
1250	* crashkernel=size[@offset]
1251	*
1252	* It returns 0 on success and -EINVAL on failure.
1253	*/
1254	static int __init parse_crashkernel_simple(char *cmdline,
1255	unsigned long long *crash_size,
1256	unsigned long long *crash_base)
1257	{
1258	char *cur = cmdline;
1259
1260	*crash_size = memparse(cmdline, &cur);
1261	if (cmdline == cur) {
1262	pr_warning("crashkernel: memory value expected\n");
1263	return -EINVAL;
1264	}
1265
1266	if (*cur == '@')
1267	*crash_base = memparse(cur+1, &cur);
1268
1269	return 0;
1270	}
1271
1272	/*
1273	* That function is the entry point for command line parsing and should be
1274	* called from the arch-specific code.
1275	*/
1276	int __init parse_crashkernel(char *cmdline,
1277	unsigned long long system_ram,
1278	unsigned long long *crash_size,
1279	unsigned long long *crash_base)
1280	{
1281	char p = cmdline, ck_cmdline = NULL;
1282	char first_colon, first_space;
1283
1284	BUG_ON(!crash_size \|\| !crash_base);
1285	*crash_size = 0;
1286	*crash_base = 0;
1287
1288	/* find crashkernel and use the last one if there are more */
1289	p = strstr(p, "crashkernel=");
1290	while (p) {
1291	ck_cmdline = p;
1292	p = strstr(p+1, "crashkernel=");
1293	}
1294
1295	if (!ck_cmdline)
1296	return -EINVAL;
1297
1298	ck_cmdline += 12; /* strlen("crashkernel=") */
1299
1300	/*
1301	* if the commandline contains a ':', then that's the extended
1302	* syntax -- if not, it must be the classic syntax
1303	*/
1304	first_colon = strchr(ck_cmdline, ':');
1305	first_space = strchr(ck_cmdline, ' ');
1306	if (first_colon && (!first_space \|\| first_colon < first_space))
1307	return parse_crashkernel_mem(ck_cmdline, system_ram,
1308	crash_size, crash_base);
1309	else
1310	return parse_crashkernel_simple(ck_cmdline, crash_size,
1311	crash_base);
1312
1313	return 0;
1314	}
1315
1316
1317
1318	void crash_save_vmcoreinfo(void)
1319	{
1320	u32 *buf;
1321
1322	if (!vmcoreinfo_size)
1323	return;
1324
1325	vmcoreinfo_append_str("CRASHTIME=%ld", get_seconds());
1326
1327	buf = (u32 *)vmcoreinfo_note;
1328
1329	buf = append_elf_note(buf, VMCOREINFO_NOTE_NAME, 0, vmcoreinfo_data,
1330	vmcoreinfo_size);
1331
1332	final_note(buf);
1333	}
1334
1335	void vmcoreinfo_append_str(const char *fmt, ...)
1336	{
1337	va_list args;
1338	char buf[0x50];
1339	int r;
1340
1341	va_start(args, fmt);
1342	r = vsnprintf(buf, sizeof(buf), fmt, args);
1343	va_end(args);
1344
1345	if (r + vmcoreinfo_size > vmcoreinfo_max_size)
1346	r = vmcoreinfo_max_size - vmcoreinfo_size;
1347
1348	memcpy(&vmcoreinfo_data[vmcoreinfo_size], buf, r);
1349
1350	vmcoreinfo_size += r;
1351	}
1352
1353	/*
1354	* provide an empty default implementation here -- architecture
1355	* code may override this
1356	*/
1357	void __attribute__ ((weak)) arch_crash_save_vmcoreinfo(void)
1358	{}
1359
1360	unsigned long __attribute__ ((weak)) paddr_vmcoreinfo_note(void)
1361	{
1362	return __pa((unsigned long)(char *)&vmcoreinfo_note);
1363	}
1364
1365	static int __init crash_save_vmcoreinfo_init(void)
1366	{
1367	VMCOREINFO_OSRELEASE(init_uts_ns.name.release);
1368	VMCOREINFO_PAGESIZE(PAGE_SIZE);
1369
1370	VMCOREINFO_SYMBOL(init_uts_ns);
1371	VMCOREINFO_SYMBOL(node_online_map);
1372	VMCOREINFO_SYMBOL(swapper_pg_dir);
1373	VMCOREINFO_SYMBOL(_stext);
1374	VMCOREINFO_SYMBOL(vmlist);
1375
1376	#ifndef CONFIG_NEED_MULTIPLE_NODES
1377	VMCOREINFO_SYMBOL(mem_map);
1378	VMCOREINFO_SYMBOL(contig_page_data);
1379	#endif
1380	#ifdef CONFIG_SPARSEMEM
1381	VMCOREINFO_SYMBOL(mem_section);
1382	VMCOREINFO_LENGTH(mem_section, NR_SECTION_ROOTS);
1383	VMCOREINFO_STRUCT_SIZE(mem_section);
1384	VMCOREINFO_OFFSET(mem_section, section_mem_map);
1385	#endif
1386	VMCOREINFO_STRUCT_SIZE(page);
1387	VMCOREINFO_STRUCT_SIZE(pglist_data);
1388	VMCOREINFO_STRUCT_SIZE(zone);
1389	VMCOREINFO_STRUCT_SIZE(free_area);
1390	VMCOREINFO_STRUCT_SIZE(list_head);
1391	VMCOREINFO_SIZE(nodemask_t);
1392	VMCOREINFO_OFFSET(page, flags);
1393	VMCOREINFO_OFFSET(page, _count);
1394	VMCOREINFO_OFFSET(page, mapping);
1395	VMCOREINFO_OFFSET(page, lru);
1396	VMCOREINFO_OFFSET(pglist_data, node_zones);
1397	VMCOREINFO_OFFSET(pglist_data, nr_zones);
1398	#ifdef CONFIG_FLAT_NODE_MEM_MAP
1399	VMCOREINFO_OFFSET(pglist_data, node_mem_map);
1400	#endif
1401	VMCOREINFO_OFFSET(pglist_data, node_start_pfn);
1402	VMCOREINFO_OFFSET(pglist_data, node_spanned_pages);
1403	VMCOREINFO_OFFSET(pglist_data, node_id);
1404	VMCOREINFO_OFFSET(zone, free_area);
1405	VMCOREINFO_OFFSET(zone, vm_stat);
1406	VMCOREINFO_OFFSET(zone, spanned_pages);
1407	VMCOREINFO_OFFSET(free_area, free_list);
1408	VMCOREINFO_OFFSET(list_head, next);
1409	VMCOREINFO_OFFSET(list_head, prev);
1410	VMCOREINFO_OFFSET(vm_struct, addr);
1411	VMCOREINFO_LENGTH(zone.free_area, MAX_ORDER);
1412	log_buf_kexec_setup();
1413	VMCOREINFO_LENGTH(free_area.free_list, MIGRATE_TYPES);
1414	VMCOREINFO_NUMBER(NR_FREE_PAGES);
1415	VMCOREINFO_NUMBER(PG_lru);
1416	VMCOREINFO_NUMBER(PG_private);
1417	VMCOREINFO_NUMBER(PG_swapcache);
1418
1419	arch_crash_save_vmcoreinfo();
1420
1421	return 0;
1422	}
1423
1424	module_init(crash_save_vmcoreinfo_init)
1425
1426	/*
1427	* Move into place and start executing a preloaded standalone
1428	* executable. If nothing was preloaded return an error.
1429	*/
1430	int kernel_kexec(void)
1431	{
1432	int error = 0;
1433
1434	if (!mutex_trylock(&kexec_mutex))
1435	return -EBUSY;
1436	if (!kexec_image) {
1437	error = -EINVAL;
1438	goto Unlock;
1439	}
1440
1441	#ifdef CONFIG_KEXEC_JUMP
1442	if (kexec_image->preserve_context) {
1443	mutex_lock(&pm_mutex);
1444	pm_prepare_console();
1445	error = freeze_processes();
1446	if (error) {
1447	error = -EBUSY;
1448	goto Restore_console;
1449	}
1450	suspend_console();
1451	error = dpm_suspend_start(PMSG_FREEZE);
1452	if (error)
1453	goto Resume_console;
1454	/* At this point, dpm_suspend_start() has been called,
1455	* but not dpm_suspend_noirq(). We must call
1456	* dpm_suspend_noirq() now. Otherwise, drivers for
1457	* some devices (e.g. interrupt controllers) become
1458	* desynchronized with the actual state of the
1459	* hardware at resume time, and evil weirdness ensues.
1460	*/
1461	error = dpm_suspend_noirq(PMSG_FREEZE);
1462	if (error)
1463	goto Resume_devices;
1464	error = disable_nonboot_cpus();
1465	if (error)
1466	goto Enable_cpus;
1467	local_irq_disable();
1468	/* Suspend system devices */
1469	error = sysdev_suspend(PMSG_FREEZE);
1470	if (error)
1471	goto Enable_irqs;
1472	} else
1473	#endif
1474	{
1475	kernel_restart_prepare(NULL);
1476	printk(KERN_EMERG "Starting new kernel\n");
1477	machine_shutdown();
1478	}
1479
1480	machine_kexec(kexec_image);
1481
1482	#ifdef CONFIG_KEXEC_JUMP
1483	if (kexec_image->preserve_context) {
1484	sysdev_resume();
1485	Enable_irqs:
1486	local_irq_enable();
1487	Enable_cpus:
1488	enable_nonboot_cpus();
1489	dpm_resume_noirq(PMSG_RESTORE);
1490	Resume_devices:
1491	dpm_resume_end(PMSG_RESTORE);
1492	Resume_console:
1493	resume_console();
1494	thaw_processes();
1495	Restore_console:
1496	pm_restore_console();
1497	mutex_unlock(&pm_mutex);
1498	}
1499	#endif
1500
1501	Unlock:
1502	mutex_unlock(&kexec_mutex);
1503	return error;
1504	}
1505

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