summaryrefslogtreecommitdiffstats
path: root/arch/s390/kernel/crash_dump.c
blob: d628afc267087cc2a01044a0113a1024846951c7 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
/*
 * S390 kdump implementation
 *
 * Copyright IBM Corp. 2011
 * Author(s): Michael Holzheu <holzheu@linux.vnet.ibm.com>
 */

#include <linux/crash_dump.h>
#include <asm/lowcore.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/gfp.h>
#include <linux/slab.h>
#include <linux/bootmem.h>
#include <linux/elf.h>
#include <asm/asm-offsets.h>
#include <linux/memblock.h>
#include <asm/os_info.h>
#include <asm/elf.h>
#include <asm/ipl.h>
#include <asm/sclp.h>

#define PTR_ADD(x, y) (((char *) (x)) + ((unsigned long) (y)))
#define PTR_SUB(x, y) (((char *) (x)) - ((unsigned long) (y)))
#define PTR_DIFF(x, y) ((unsigned long)(((char *) (x)) - ((unsigned long) (y))))

static struct memblock_region oldmem_region;

static struct memblock_type oldmem_type = {
	.cnt = 1,
	.max = 1,
	.total_size = 0,
	.regions = &oldmem_region,
	.name = "oldmem",
};

struct save_area {
	struct list_head list;
	u64 psw[2];
	u64 ctrs[16];
	u64 gprs[16];
	u32 acrs[16];
	u64 fprs[16];
	u32 fpc;
	u32 prefix;
	u64 todpreg;
	u64 timer;
	u64 todcmp;
	u64 vxrs_low[16];
	__vector128 vxrs_high[16];
};

static LIST_HEAD(dump_save_areas);

/*
 * Allocate a save area
 */
struct save_area * __init save_area_alloc(bool is_boot_cpu)
{
	struct save_area *sa;

	sa = (void *) memblock_alloc(sizeof(*sa), 8);
	if (is_boot_cpu)
		list_add(&sa->list, &dump_save_areas);
	else
		list_add_tail(&sa->list, &dump_save_areas);
	return sa;
}

/*
 * Return the address of the save area for the boot CPU
 */
struct save_area * __init save_area_boot_cpu(void)
{
	return list_first_entry_or_null(&dump_save_areas, struct save_area, list);
}

/*
 * Copy CPU registers into the save area
 */
void __init save_area_add_regs(struct save_area *sa, void *regs)
{
	struct lowcore *lc;

	lc = (struct lowcore *)(regs - __LC_FPREGS_SAVE_AREA);
	memcpy(&sa->psw, &lc->psw_save_area, sizeof(sa->psw));
	memcpy(&sa->ctrs, &lc->cregs_save_area, sizeof(sa->ctrs));
	memcpy(&sa->gprs, &lc->gpregs_save_area, sizeof(sa->gprs));
	memcpy(&sa->acrs, &lc->access_regs_save_area, sizeof(sa->acrs));
	memcpy(&sa->fprs, &lc->floating_pt_save_area, sizeof(sa->fprs));
	memcpy(&sa->fpc, &lc->fpt_creg_save_area, sizeof(sa->fpc));
	memcpy(&sa->prefix, &lc->prefixreg_save_area, sizeof(sa->prefix));
	memcpy(&sa->todpreg, &lc->tod_progreg_save_area, sizeof(sa->todpreg));
	memcpy(&sa->timer, &lc->cpu_timer_save_area, sizeof(sa->timer));
	memcpy(&sa->todcmp, &lc->clock_comp_save_area, sizeof(sa->todcmp));
}

/*
 * Copy vector registers into the save area
 */
void __init save_area_add_vxrs(struct save_area *sa, __vector128 *vxrs)
{
	int i;

	/* Copy lower halves of vector registers 0-15 */
	for (i = 0; i < 16; i++)
		memcpy(&sa->vxrs_low[i], &vxrs[i].u[2], 8);
	/* Copy vector registers 16-31 */
	memcpy(sa->vxrs_high, vxrs + 16, 16 * sizeof(__vector128));
}

/*
 * Return physical address for virtual address
 */
static inline void *load_real_addr(void *addr)
{
	unsigned long real_addr;

	asm volatile(
		   "	lra     %0,0(%1)\n"
		   "	jz	0f\n"
		   "	la	%0,0\n"
		   "0:"
		   : "=a" (real_addr) : "a" (addr) : "cc");
	return (void *)real_addr;
}

/*
 * Copy memory of the old, dumped system to a kernel space virtual address
 */
int copy_oldmem_kernel(void *dst, void *src, size_t count)
{
	unsigned long from, len;
	void *ra;
	int rc;

	while (count) {
		from = __pa(src);
		if (!OLDMEM_BASE && from < sclp.hsa_size) {
			/* Copy from zfcpdump HSA area */
			len = min(count, sclp.hsa_size - from);
			rc = memcpy_hsa_kernel(dst, from, len);
			if (rc)
				return rc;
		} else {
			/* Check for swapped kdump oldmem areas */
			if (OLDMEM_BASE && from - OLDMEM_BASE < OLDMEM_SIZE) {
				from -= OLDMEM_BASE;
				len = min(count, OLDMEM_SIZE - from);
			} else if (OLDMEM_BASE && from < OLDMEM_SIZE) {
				len = min(count, OLDMEM_SIZE - from);
				from += OLDMEM_BASE;
			} else {
				len = count;
			}
			if (is_vmalloc_or_module_addr(dst)) {
				ra = load_real_addr(dst);
				len = min(PAGE_SIZE - offset_in_page(ra), len);
			} else {
				ra = dst;
			}
			if (memcpy_real(ra, (void *) from, len))
				return -EFAULT;
		}
		dst += len;
		src += len;
		count -= len;
	}
	return 0;
}

/*
 * Copy memory of the old, dumped system to a user space virtual address
 */
static int copy_oldmem_user(void __user *dst, void *src, size_t count)
{
	unsigned long from, len;
	int rc;

	while (count) {
		from = __pa(src);
		if (!OLDMEM_BASE && from < sclp.hsa_size) {
			/* Copy from zfcpdump HSA area */
			len = min(count, sclp.hsa_size - from);
			rc = memcpy_hsa_user(dst, from, len);
			if (rc)
				return rc;
		} else {
			/* Check for swapped kdump oldmem areas */
			if (OLDMEM_BASE && from - OLDMEM_BASE < OLDMEM_SIZE) {
				from -= OLDMEM_BASE;
				len = min(count, OLDMEM_SIZE - from);
			} else if (OLDMEM_BASE && from < OLDMEM_SIZE) {
				len = min(count, OLDMEM_SIZE - from);
				from += OLDMEM_BASE;
			} else {
				len = count;
			}
			rc = copy_to_user_real(dst, (void *) from, count);
			if (rc)
				return rc;
		}
		dst += len;
		src += len;
		count -= len;
	}
	return 0;
}

/*
 * Copy one page from "oldmem"
 */
ssize_t copy_oldmem_page(unsigned long pfn, char *buf, size_t csize,
			 unsigned long offset, int userbuf)
{
	void *src;
	int rc;

	if (!csize)
		return 0;
	src = (void *) (pfn << PAGE_SHIFT) + offset;
	if (userbuf)
		rc = copy_oldmem_user((void __force __user *) buf, src, csize);
	else
		rc = copy_oldmem_kernel((void *) buf, src, csize);
	return rc;
}

/*
 * Remap "oldmem" for kdump
 *
 * For the kdump reserved memory this functions performs a swap operation:
 * [0 - OLDMEM_SIZE] is mapped to [OLDMEM_BASE - OLDMEM_BASE + OLDMEM_SIZE]
 */
static int remap_oldmem_pfn_range_kdump(struct vm_area_struct *vma,
					unsigned long from, unsigned long pfn,
					unsigned long size, pgprot_t prot)
{
	unsigned long size_old;
	int rc;

	if (pfn < OLDMEM_SIZE >> PAGE_SHIFT) {
		size_old = min(size, OLDMEM_SIZE - (pfn << PAGE_SHIFT));
		rc = remap_pfn_range(vma, from,
				     pfn + (OLDMEM_BASE >> PAGE_SHIFT),
				     size_old, prot);
		if (rc || size == size_old)
			return rc;
		size -= size_old;
		from += size_old;
		pfn += size_old >> PAGE_SHIFT;
	}
	return remap_pfn_range(vma, from, pfn, size, prot);
}

/*
 * Remap "oldmem" for zfcpdump
 *
 * We only map available memory above HSA size. Memory below HSA size
 * is read on demand using the copy_oldmem_page() function.
 */
static int remap_oldmem_pfn_range_zfcpdump(struct vm_area_struct *vma,
					   unsigned long from,
					   unsigned long pfn,
					   unsigned long size, pgprot_t prot)
{
	unsigned long hsa_end = sclp.hsa_size;
	unsigned long size_hsa;

	if (pfn < hsa_end >> PAGE_SHIFT) {
		size_hsa = min(size, hsa_end - (pfn << PAGE_SHIFT));
		if (size == size_hsa)
			return 0;
		size -= size_hsa;
		from += size_hsa;
		pfn += size_hsa >> PAGE_SHIFT;
	}
	return remap_pfn_range(vma, from, pfn, size, prot);
}

/*
 * Remap "oldmem" for kdump or zfcpdump
 */
int remap_oldmem_pfn_range(struct vm_area_struct *vma, unsigned long from,
			   unsigned long pfn, unsigned long size, pgprot_t prot)
{
	if (OLDMEM_BASE)
		return remap_oldmem_pfn_range_kdump(vma, from, pfn, size, prot);
	else
		return remap_oldmem_pfn_range_zfcpdump(vma, from, pfn, size,
						       prot);
}

/*
 * Alloc memory and panic in case of ENOMEM
 */
static void *kzalloc_panic(int len)
{
	void *rc;

	rc = kzalloc(len, GFP_KERNEL);
	if (!rc)
		panic("s390 kdump kzalloc (%d) failed", len);
	return rc;
}

/*
 * Initialize ELF note
 */
static void *nt_init_name(void *buf, Elf64_Word type, void *desc, int d_len,
			  const char *name)
{
	Elf64_Nhdr *note;
	u64 len;

	note = (Elf64_Nhdr *)buf;
	note->n_namesz = strlen(name) + 1;
	note->n_descsz = d_len;
	note->n_type = type;
	len = sizeof(Elf64_Nhdr);

	memcpy(buf + len, name, note->n_namesz);
	len = roundup(len + note->n_namesz, 4);

	memcpy(buf + len, desc, note->n_descsz);
	len = roundup(len + note->n_descsz, 4);

	return PTR_ADD(buf, len);
}

static inline void *nt_init(void *buf, Elf64_Word type, void *desc, int d_len)
{
	const char *note_name = "LINUX";

	if (type == NT_PRPSINFO || type == NT_PRSTATUS || type == NT_PRFPREG)
		note_name = KEXEC_CORE_NOTE_NAME;
	return nt_init_name(buf, type, desc, d_len, note_name);
}

/*
 * Fill ELF notes for one CPU with save area registers
 */
static void *fill_cpu_elf_notes(void *ptr, int cpu, struct save_area *sa)
{
	struct elf_prstatus nt_prstatus;
	elf_fpregset_t nt_fpregset;

	/* Prepare prstatus note */
	memset(&nt_prstatus, 0, sizeof(nt_prstatus));
	memcpy(&nt_prstatus.pr_reg.gprs, sa->gprs, sizeof(sa->gprs));
	memcpy(&nt_prstatus.pr_reg.psw, sa->psw, sizeof(sa->psw));
	memcpy(&nt_prstatus.pr_reg.acrs, sa->acrs, sizeof(sa->acrs));
	nt_prstatus.pr_pid = cpu;
	/* Prepare fpregset (floating point) note */
	memset(&nt_fpregset, 0, sizeof(nt_fpregset));
	memcpy(&nt_fpregset.fpc, &sa->fpc, sizeof(sa->fpc));
	memcpy(&nt_fpregset.fprs, &sa->fprs, sizeof(sa->fprs));
	/* Create ELF notes for the CPU */
	ptr = nt_init(ptr, NT_PRSTATUS, &nt_prstatus, sizeof(nt_prstatus));
	ptr = nt_init(ptr, NT_PRFPREG, &nt_fpregset, sizeof(nt_fpregset));
	ptr = nt_init(ptr, NT_S390_TIMER, &sa->timer, sizeof(sa->timer));
	ptr = nt_init(ptr, NT_S390_TODCMP, &sa->todcmp, sizeof(sa->todcmp));
	ptr = nt_init(ptr, NT_S390_TODPREG, &sa->todpreg, sizeof(sa->todpreg));
	ptr = nt_init(ptr, NT_S390_CTRS, &sa->ctrs, sizeof(sa->ctrs));
	ptr = nt_init(ptr, NT_S390_PREFIX, &sa->prefix, sizeof(sa->prefix));
	if (MACHINE_HAS_VX) {
		ptr = nt_init(ptr, NT_S390_VXRS_HIGH,
			      &sa->vxrs_high, sizeof(sa->vxrs_high));
		ptr = nt_init(ptr, NT_S390_VXRS_LOW,
			      &sa->vxrs_low, sizeof(sa->vxrs_low));
	}
	return ptr;
}

/*
 * Initialize prpsinfo note (new kernel)
 */
static void *nt_prpsinfo(void *ptr)
{
	struct elf_prpsinfo prpsinfo;

	memset(&prpsinfo, 0, sizeof(prpsinfo));
	prpsinfo.pr_sname = 'R';
	strcpy(prpsinfo.pr_fname, "vmlinux");
	return nt_init(ptr, NT_PRPSINFO, &prpsinfo, sizeof(prpsinfo));
}

/*
 * Get vmcoreinfo using lowcore->vmcore_info (new kernel)
 */
static void *get_vmcoreinfo_old(unsigned long *size)
{
	char nt_name[11], *vmcoreinfo;
	Elf64_Nhdr note;
	void *addr;

	if (copy_oldmem_kernel(&addr, &S390_lowcore.vmcore_info, sizeof(addr)))
		return NULL;
	memset(nt_name, 0, sizeof(nt_name));
	if (copy_oldmem_kernel(&note, addr, sizeof(note)))
		return NULL;
	if (copy_oldmem_kernel(nt_name, addr + sizeof(note),
			       sizeof(nt_name) - 1))
		return NULL;
	if (strcmp(nt_name, "VMCOREINFO") != 0)
		return NULL;
	vmcoreinfo = kzalloc_panic(note.n_descsz);
	if (copy_oldmem_kernel(vmcoreinfo, addr + 24, note.n_descsz))
		return NULL;
	*size = note.n_descsz;
	return vmcoreinfo;
}

/*
 * Initialize vmcoreinfo note (new kernel)
 */
static void *nt_vmcoreinfo(void *ptr)
{
	unsigned long size;
	void *vmcoreinfo;

	vmcoreinfo = os_info_old_entry(OS_INFO_VMCOREINFO, &size);
	if (!vmcoreinfo)
		vmcoreinfo = get_vmcoreinfo_old(&size);
	if (!vmcoreinfo)
		return ptr;
	return nt_init_name(ptr, 0, vmcoreinfo, size, "VMCOREINFO");
}

/*
 * Initialize final note (needed for /proc/vmcore code)
 */
static void *nt_final(void *ptr)
{
	Elf64_Nhdr *note;

	note = (Elf64_Nhdr *) ptr;
	note->n_namesz = 0;
	note->n_descsz = 0;
	note->n_type = 0;
	return PTR_ADD(ptr, sizeof(Elf64_Nhdr));
}

/*
 * Initialize ELF header (new kernel)
 */
static void *ehdr_init(Elf64_Ehdr *ehdr, int mem_chunk_cnt)
{
	memset(ehdr, 0, sizeof(*ehdr));
	memcpy(ehdr->e_ident, ELFMAG, SELFMAG);
	ehdr->e_ident[EI_CLASS] = ELFCLASS64;
	ehdr->e_ident[EI_DATA] = ELFDATA2MSB;
	ehdr->e_ident[EI_VERSION] = EV_CURRENT;
	memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD);
	ehdr->e_type = ET_CORE;
	ehdr->e_machine = EM_S390;
	ehdr->e_version = EV_CURRENT;
	ehdr->e_phoff = sizeof(Elf64_Ehdr);
	ehdr->e_ehsize = sizeof(Elf64_Ehdr);
	ehdr->e_phentsize = sizeof(Elf64_Phdr);
	ehdr->e_phnum = mem_chunk_cnt + 1;
	return ehdr + 1;
}

/*
 * Return CPU count for ELF header (new kernel)
 */
static int get_cpu_cnt(void)
{
	struct save_area *sa;
	int cpus = 0;

	list_for_each_entry(sa, &dump_save_areas, list)
		if (sa->prefix != 0)
			cpus++;
	return cpus;
}

/*
 * Return memory chunk count for ELF header (new kernel)
 */
static int get_mem_chunk_cnt(void)
{
	int cnt = 0;
	u64 idx;

	for_each_mem_range(idx, &memblock.physmem, &oldmem_type, NUMA_NO_NODE,
			   MEMBLOCK_NONE, NULL, NULL, NULL)
		cnt++;
	return cnt;
}

/*
 * Initialize ELF loads (new kernel)
 */
static void loads_init(Elf64_Phdr *phdr, u64 loads_offset)
{
	phys_addr_t start, end;
	u64 idx;

	for_each_mem_range(idx, &memblock.physmem, &oldmem_type, NUMA_NO_NODE,
			   MEMBLOCK_NONE, &start, &end, NULL) {
		phdr->p_filesz = end - start;
		phdr->p_type = PT_LOAD;
		phdr->p_offset = start;
		phdr->p_vaddr = start;
		phdr->p_paddr = start;
		phdr->p_memsz = end - start;
		phdr->p_flags = PF_R | PF_W | PF_X;
		phdr->p_align = PAGE_SIZE;
		phdr++;
	}
}

/*
 * Initialize notes (new kernel)
 */
static void *notes_init(Elf64_Phdr *phdr, void *ptr, u64 notes_offset)
{
	struct save_area *sa;
	void *ptr_start = ptr;
	int cpu;

	ptr = nt_prpsinfo(ptr);

	cpu = 1;
	list_for_each_entry(sa, &dump_save_areas, list)
		if (sa->prefix != 0)
			ptr = fill_cpu_elf_notes(ptr, cpu++, sa);
	ptr = nt_vmcoreinfo(ptr);
	ptr = nt_final(ptr);
	memset(phdr, 0, sizeof(*phdr));
	phdr->p_type = PT_NOTE;
	phdr->p_offset = notes_offset;
	phdr->p_filesz = (unsigned long) PTR_SUB(ptr, ptr_start);
	phdr->p_memsz = phdr->p_filesz;
	return ptr;
}

/*
 * Create ELF core header (new kernel)
 */
int elfcorehdr_alloc(unsigned long long *addr, unsigned long long *size)
{
	Elf64_Phdr *phdr_notes, *phdr_loads;
	int mem_chunk_cnt;
	void *ptr, *hdr;
	u32 alloc_size;
	u64 hdr_off;

	/* If we are not in kdump or zfcpdump mode return */
	if (!OLDMEM_BASE && ipl_info.type != IPL_TYPE_FCP_DUMP)
		return 0;
	/* If we cannot get HSA size for zfcpdump return error */
	if (ipl_info.type == IPL_TYPE_FCP_DUMP && !sclp.hsa_size)
		return -ENODEV;

	/* For kdump, exclude previous crashkernel memory */
	if (OLDMEM_BASE) {
		oldmem_region.base = OLDMEM_BASE;
		oldmem_region.size = OLDMEM_SIZE;
		oldmem_type.total_size = OLDMEM_SIZE;
	}

	mem_chunk_cnt = get_mem_chunk_cnt();

	alloc_size = 0x1000 + get_cpu_cnt() * 0x4a0 +
		mem_chunk_cnt * sizeof(Elf64_Phdr);
	hdr = kzalloc_panic(alloc_size);
	/* Init elf header */
	ptr = ehdr_init(hdr, mem_chunk_cnt);
	/* Init program headers */
	phdr_notes = ptr;
	ptr = PTR_ADD(ptr, sizeof(Elf64_Phdr));
	phdr_loads = ptr;
	ptr = PTR_ADD(ptr, sizeof(Elf64_Phdr) * mem_chunk_cnt);
	/* Init notes */
	hdr_off = PTR_DIFF(ptr, hdr);
	ptr = notes_init(phdr_notes, ptr, ((unsigned long) hdr) + hdr_off);
	/* Init loads */
	hdr_off = PTR_DIFF(ptr, hdr);
	loads_init(phdr_loads, hdr_off);
	*addr = (unsigned long long) hdr;
	*size = (unsigned long long) hdr_off;
	BUG_ON(elfcorehdr_size > alloc_size);
	return 0;
}

/*
 * Free ELF core header (new kernel)
 */
void elfcorehdr_free(unsigned long long addr)
{
	kfree((void *)(unsigned long)addr);
}

/*
 * Read from ELF header
 */
ssize_t elfcorehdr_read(char *buf, size_t count, u64 *ppos)
{
	void *src = (void *)(unsigned long)*ppos;

	memcpy(buf, src, count);
	*ppos += count;
	return count;
}

/*
 * Read from ELF notes data
 */
ssize_t elfcorehdr_read_notes(char *buf, size_t count, u64 *ppos)
{
	void *src = (void *)(unsigned long)*ppos;

	memcpy(buf, src, count);
	*ppos += count;
	return count;
}