GNU Linux-libre 4.9.288-gnu1
[releases.git] / arch / s390 / kernel / crash_dump.c
1 /*
2  * S390 kdump implementation
3  *
4  * Copyright IBM Corp. 2011
5  * Author(s): Michael Holzheu <holzheu@linux.vnet.ibm.com>
6  */
7
8 #include <linux/crash_dump.h>
9 #include <asm/lowcore.h>
10 #include <linux/kernel.h>
11 #include <linux/module.h>
12 #include <linux/gfp.h>
13 #include <linux/slab.h>
14 #include <linux/bootmem.h>
15 #include <linux/elf.h>
16 #include <asm/asm-offsets.h>
17 #include <linux/memblock.h>
18 #include <asm/os_info.h>
19 #include <asm/elf.h>
20 #include <asm/ipl.h>
21 #include <asm/sclp.h>
22
23 #define PTR_ADD(x, y) (((char *) (x)) + ((unsigned long) (y)))
24 #define PTR_SUB(x, y) (((char *) (x)) - ((unsigned long) (y)))
25 #define PTR_DIFF(x, y) ((unsigned long)(((char *) (x)) - ((unsigned long) (y))))
26
27 static struct memblock_region oldmem_region;
28
29 static struct memblock_type oldmem_type = {
30         .cnt = 1,
31         .max = 1,
32         .total_size = 0,
33         .regions = &oldmem_region,
34 };
35
36 struct save_area {
37         struct list_head list;
38         u64 psw[2];
39         u64 ctrs[16];
40         u64 gprs[16];
41         u32 acrs[16];
42         u64 fprs[16];
43         u32 fpc;
44         u32 prefix;
45         u64 todpreg;
46         u64 timer;
47         u64 todcmp;
48         u64 vxrs_low[16];
49         __vector128 vxrs_high[16];
50 };
51
52 static LIST_HEAD(dump_save_areas);
53
54 /*
55  * Allocate a save area
56  */
57 struct save_area * __init save_area_alloc(bool is_boot_cpu)
58 {
59         struct save_area *sa;
60
61         sa = (void *) memblock_alloc(sizeof(*sa), 8);
62         if (is_boot_cpu)
63                 list_add(&sa->list, &dump_save_areas);
64         else
65                 list_add_tail(&sa->list, &dump_save_areas);
66         return sa;
67 }
68
69 /*
70  * Return the address of the save area for the boot CPU
71  */
72 struct save_area * __init save_area_boot_cpu(void)
73 {
74         return list_first_entry_or_null(&dump_save_areas, struct save_area, list);
75 }
76
77 /*
78  * Copy CPU registers into the save area
79  */
80 void __init save_area_add_regs(struct save_area *sa, void *regs)
81 {
82         struct lowcore *lc;
83
84         lc = (struct lowcore *)(regs - __LC_FPREGS_SAVE_AREA);
85         memcpy(&sa->psw, &lc->psw_save_area, sizeof(sa->psw));
86         memcpy(&sa->ctrs, &lc->cregs_save_area, sizeof(sa->ctrs));
87         memcpy(&sa->gprs, &lc->gpregs_save_area, sizeof(sa->gprs));
88         memcpy(&sa->acrs, &lc->access_regs_save_area, sizeof(sa->acrs));
89         memcpy(&sa->fprs, &lc->floating_pt_save_area, sizeof(sa->fprs));
90         memcpy(&sa->fpc, &lc->fpt_creg_save_area, sizeof(sa->fpc));
91         memcpy(&sa->prefix, &lc->prefixreg_save_area, sizeof(sa->prefix));
92         memcpy(&sa->todpreg, &lc->tod_progreg_save_area, sizeof(sa->todpreg));
93         memcpy(&sa->timer, &lc->cpu_timer_save_area, sizeof(sa->timer));
94         memcpy(&sa->todcmp, &lc->clock_comp_save_area, sizeof(sa->todcmp));
95 }
96
97 /*
98  * Copy vector registers into the save area
99  */
100 void __init save_area_add_vxrs(struct save_area *sa, __vector128 *vxrs)
101 {
102         int i;
103
104         /* Copy lower halves of vector registers 0-15 */
105         for (i = 0; i < 16; i++)
106                 memcpy(&sa->vxrs_low[i], &vxrs[i].u[2], 8);
107         /* Copy vector registers 16-31 */
108         memcpy(sa->vxrs_high, vxrs + 16, 16 * sizeof(__vector128));
109 }
110
111 /*
112  * Return physical address for virtual address
113  */
114 static inline void *load_real_addr(void *addr)
115 {
116         unsigned long real_addr;
117
118         asm volatile(
119                    "    lra     %0,0(%1)\n"
120                    "    jz      0f\n"
121                    "    la      %0,0\n"
122                    "0:"
123                    : "=a" (real_addr) : "a" (addr) : "cc");
124         return (void *)real_addr;
125 }
126
127 /*
128  * Copy memory of the old, dumped system to a kernel space virtual address
129  */
130 int copy_oldmem_kernel(void *dst, void *src, size_t count)
131 {
132         unsigned long from, len;
133         void *ra;
134         int rc;
135
136         while (count) {
137                 from = __pa(src);
138                 if (!OLDMEM_BASE && from < sclp.hsa_size) {
139                         /* Copy from zfcpdump HSA area */
140                         len = min(count, sclp.hsa_size - from);
141                         rc = memcpy_hsa_kernel(dst, from, len);
142                         if (rc)
143                                 return rc;
144                 } else {
145                         /* Check for swapped kdump oldmem areas */
146                         if (OLDMEM_BASE && from - OLDMEM_BASE < OLDMEM_SIZE) {
147                                 from -= OLDMEM_BASE;
148                                 len = min(count, OLDMEM_SIZE - from);
149                         } else if (OLDMEM_BASE && from < OLDMEM_SIZE) {
150                                 len = min(count, OLDMEM_SIZE - from);
151                                 from += OLDMEM_BASE;
152                         } else {
153                                 len = count;
154                         }
155                         if (is_vmalloc_or_module_addr(dst)) {
156                                 ra = load_real_addr(dst);
157                                 len = min(PAGE_SIZE - offset_in_page(ra), len);
158                         } else {
159                                 ra = dst;
160                         }
161                         if (memcpy_real(ra, (void *) from, len))
162                                 return -EFAULT;
163                 }
164                 dst += len;
165                 src += len;
166                 count -= len;
167         }
168         return 0;
169 }
170
171 /*
172  * Copy memory of the old, dumped system to a user space virtual address
173  */
174 static int copy_oldmem_user(void __user *dst, void *src, size_t count)
175 {
176         unsigned long from, len;
177         int rc;
178
179         while (count) {
180                 from = __pa(src);
181                 if (!OLDMEM_BASE && from < sclp.hsa_size) {
182                         /* Copy from zfcpdump HSA area */
183                         len = min(count, sclp.hsa_size - from);
184                         rc = memcpy_hsa_user(dst, from, len);
185                         if (rc)
186                                 return rc;
187                 } else {
188                         /* Check for swapped kdump oldmem areas */
189                         if (OLDMEM_BASE && from - OLDMEM_BASE < OLDMEM_SIZE) {
190                                 from -= OLDMEM_BASE;
191                                 len = min(count, OLDMEM_SIZE - from);
192                         } else if (OLDMEM_BASE && from < OLDMEM_SIZE) {
193                                 len = min(count, OLDMEM_SIZE - from);
194                                 from += OLDMEM_BASE;
195                         } else {
196                                 len = count;
197                         }
198                         rc = copy_to_user_real(dst, (void *) from, count);
199                         if (rc)
200                                 return rc;
201                 }
202                 dst += len;
203                 src += len;
204                 count -= len;
205         }
206         return 0;
207 }
208
209 /*
210  * Copy one page from "oldmem"
211  */
212 ssize_t copy_oldmem_page(unsigned long pfn, char *buf, size_t csize,
213                          unsigned long offset, int userbuf)
214 {
215         void *src;
216         int rc;
217
218         if (!csize)
219                 return 0;
220         src = (void *) (pfn << PAGE_SHIFT) + offset;
221         if (userbuf)
222                 rc = copy_oldmem_user((void __force __user *) buf, src, csize);
223         else
224                 rc = copy_oldmem_kernel((void *) buf, src, csize);
225         return rc;
226 }
227
228 /*
229  * Remap "oldmem" for kdump
230  *
231  * For the kdump reserved memory this functions performs a swap operation:
232  * [0 - OLDMEM_SIZE] is mapped to [OLDMEM_BASE - OLDMEM_BASE + OLDMEM_SIZE]
233  */
234 static int remap_oldmem_pfn_range_kdump(struct vm_area_struct *vma,
235                                         unsigned long from, unsigned long pfn,
236                                         unsigned long size, pgprot_t prot)
237 {
238         unsigned long size_old;
239         int rc;
240
241         if (pfn < OLDMEM_SIZE >> PAGE_SHIFT) {
242                 size_old = min(size, OLDMEM_SIZE - (pfn << PAGE_SHIFT));
243                 rc = remap_pfn_range(vma, from,
244                                      pfn + (OLDMEM_BASE >> PAGE_SHIFT),
245                                      size_old, prot);
246                 if (rc || size == size_old)
247                         return rc;
248                 size -= size_old;
249                 from += size_old;
250                 pfn += size_old >> PAGE_SHIFT;
251         }
252         return remap_pfn_range(vma, from, pfn, size, prot);
253 }
254
255 /*
256  * Remap "oldmem" for zfcpdump
257  *
258  * We only map available memory above HSA size. Memory below HSA size
259  * is read on demand using the copy_oldmem_page() function.
260  */
261 static int remap_oldmem_pfn_range_zfcpdump(struct vm_area_struct *vma,
262                                            unsigned long from,
263                                            unsigned long pfn,
264                                            unsigned long size, pgprot_t prot)
265 {
266         unsigned long hsa_end = sclp.hsa_size;
267         unsigned long size_hsa;
268
269         if (pfn < hsa_end >> PAGE_SHIFT) {
270                 size_hsa = min(size, hsa_end - (pfn << PAGE_SHIFT));
271                 if (size == size_hsa)
272                         return 0;
273                 size -= size_hsa;
274                 from += size_hsa;
275                 pfn += size_hsa >> PAGE_SHIFT;
276         }
277         return remap_pfn_range(vma, from, pfn, size, prot);
278 }
279
280 /*
281  * Remap "oldmem" for kdump or zfcpdump
282  */
283 int remap_oldmem_pfn_range(struct vm_area_struct *vma, unsigned long from,
284                            unsigned long pfn, unsigned long size, pgprot_t prot)
285 {
286         if (OLDMEM_BASE)
287                 return remap_oldmem_pfn_range_kdump(vma, from, pfn, size, prot);
288         else
289                 return remap_oldmem_pfn_range_zfcpdump(vma, from, pfn, size,
290                                                        prot);
291 }
292
293 /*
294  * Alloc memory and panic in case of ENOMEM
295  */
296 static void *kzalloc_panic(int len)
297 {
298         void *rc;
299
300         rc = kzalloc(len, GFP_KERNEL);
301         if (!rc)
302                 panic("s390 kdump kzalloc (%d) failed", len);
303         return rc;
304 }
305
306 /*
307  * Initialize ELF note
308  */
309 static void *nt_init_name(void *buf, Elf64_Word type, void *desc, int d_len,
310                           const char *name)
311 {
312         Elf64_Nhdr *note;
313         u64 len;
314
315         note = (Elf64_Nhdr *)buf;
316         note->n_namesz = strlen(name) + 1;
317         note->n_descsz = d_len;
318         note->n_type = type;
319         len = sizeof(Elf64_Nhdr);
320
321         memcpy(buf + len, name, note->n_namesz);
322         len = roundup(len + note->n_namesz, 4);
323
324         memcpy(buf + len, desc, note->n_descsz);
325         len = roundup(len + note->n_descsz, 4);
326
327         return PTR_ADD(buf, len);
328 }
329
330 static inline void *nt_init(void *buf, Elf64_Word type, void *desc, int d_len)
331 {
332         const char *note_name = "LINUX";
333
334         if (type == NT_PRPSINFO || type == NT_PRSTATUS || type == NT_PRFPREG)
335                 note_name = KEXEC_CORE_NOTE_NAME;
336         return nt_init_name(buf, type, desc, d_len, note_name);
337 }
338
339 /*
340  * Fill ELF notes for one CPU with save area registers
341  */
342 static void *fill_cpu_elf_notes(void *ptr, int cpu, struct save_area *sa)
343 {
344         struct elf_prstatus nt_prstatus;
345         elf_fpregset_t nt_fpregset;
346
347         /* Prepare prstatus note */
348         memset(&nt_prstatus, 0, sizeof(nt_prstatus));
349         memcpy(&nt_prstatus.pr_reg.gprs, sa->gprs, sizeof(sa->gprs));
350         memcpy(&nt_prstatus.pr_reg.psw, sa->psw, sizeof(sa->psw));
351         memcpy(&nt_prstatus.pr_reg.acrs, sa->acrs, sizeof(sa->acrs));
352         nt_prstatus.pr_pid = cpu;
353         /* Prepare fpregset (floating point) note */
354         memset(&nt_fpregset, 0, sizeof(nt_fpregset));
355         memcpy(&nt_fpregset.fpc, &sa->fpc, sizeof(sa->fpc));
356         memcpy(&nt_fpregset.fprs, &sa->fprs, sizeof(sa->fprs));
357         /* Create ELF notes for the CPU */
358         ptr = nt_init(ptr, NT_PRSTATUS, &nt_prstatus, sizeof(nt_prstatus));
359         ptr = nt_init(ptr, NT_PRFPREG, &nt_fpregset, sizeof(nt_fpregset));
360         ptr = nt_init(ptr, NT_S390_TIMER, &sa->timer, sizeof(sa->timer));
361         ptr = nt_init(ptr, NT_S390_TODCMP, &sa->todcmp, sizeof(sa->todcmp));
362         ptr = nt_init(ptr, NT_S390_TODPREG, &sa->todpreg, sizeof(sa->todpreg));
363         ptr = nt_init(ptr, NT_S390_CTRS, &sa->ctrs, sizeof(sa->ctrs));
364         ptr = nt_init(ptr, NT_S390_PREFIX, &sa->prefix, sizeof(sa->prefix));
365         if (MACHINE_HAS_VX) {
366                 ptr = nt_init(ptr, NT_S390_VXRS_HIGH,
367                               &sa->vxrs_high, sizeof(sa->vxrs_high));
368                 ptr = nt_init(ptr, NT_S390_VXRS_LOW,
369                               &sa->vxrs_low, sizeof(sa->vxrs_low));
370         }
371         return ptr;
372 }
373
374 /*
375  * Initialize prpsinfo note (new kernel)
376  */
377 static void *nt_prpsinfo(void *ptr)
378 {
379         struct elf_prpsinfo prpsinfo;
380
381         memset(&prpsinfo, 0, sizeof(prpsinfo));
382         prpsinfo.pr_sname = 'R';
383         strcpy(prpsinfo.pr_fname, "vmlinux");
384         return nt_init(ptr, NT_PRPSINFO, &prpsinfo, sizeof(prpsinfo));
385 }
386
387 /*
388  * Get vmcoreinfo using lowcore->vmcore_info (new kernel)
389  */
390 static void *get_vmcoreinfo_old(unsigned long *size)
391 {
392         char nt_name[11], *vmcoreinfo;
393         Elf64_Nhdr note;
394         void *addr;
395
396         if (copy_oldmem_kernel(&addr, &S390_lowcore.vmcore_info, sizeof(addr)))
397                 return NULL;
398         memset(nt_name, 0, sizeof(nt_name));
399         if (copy_oldmem_kernel(&note, addr, sizeof(note)))
400                 return NULL;
401         if (copy_oldmem_kernel(nt_name, addr + sizeof(note),
402                                sizeof(nt_name) - 1))
403                 return NULL;
404         if (strcmp(nt_name, VMCOREINFO_NOTE_NAME) != 0)
405                 return NULL;
406         vmcoreinfo = kzalloc_panic(note.n_descsz);
407         if (copy_oldmem_kernel(vmcoreinfo, addr + 24, note.n_descsz)) {
408                 kfree(vmcoreinfo);
409                 return NULL;
410         }
411         *size = note.n_descsz;
412         return vmcoreinfo;
413 }
414
415 /*
416  * Initialize vmcoreinfo note (new kernel)
417  */
418 static void *nt_vmcoreinfo(void *ptr)
419 {
420         const char *name = VMCOREINFO_NOTE_NAME;
421         unsigned long size;
422         void *vmcoreinfo;
423
424         vmcoreinfo = os_info_old_entry(OS_INFO_VMCOREINFO, &size);
425         if (vmcoreinfo)
426                 return nt_init_name(ptr, 0, vmcoreinfo, size, name);
427
428         vmcoreinfo = get_vmcoreinfo_old(&size);
429         if (!vmcoreinfo)
430                 return ptr;
431         ptr = nt_init_name(ptr, 0, vmcoreinfo, size, name);
432         kfree(vmcoreinfo);
433         return ptr;
434 }
435
436 /*
437  * Initialize final note (needed for /proc/vmcore code)
438  */
439 static void *nt_final(void *ptr)
440 {
441         Elf64_Nhdr *note;
442
443         note = (Elf64_Nhdr *) ptr;
444         note->n_namesz = 0;
445         note->n_descsz = 0;
446         note->n_type = 0;
447         return PTR_ADD(ptr, sizeof(Elf64_Nhdr));
448 }
449
450 /*
451  * Initialize ELF header (new kernel)
452  */
453 static void *ehdr_init(Elf64_Ehdr *ehdr, int mem_chunk_cnt)
454 {
455         memset(ehdr, 0, sizeof(*ehdr));
456         memcpy(ehdr->e_ident, ELFMAG, SELFMAG);
457         ehdr->e_ident[EI_CLASS] = ELFCLASS64;
458         ehdr->e_ident[EI_DATA] = ELFDATA2MSB;
459         ehdr->e_ident[EI_VERSION] = EV_CURRENT;
460         memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD);
461         ehdr->e_type = ET_CORE;
462         ehdr->e_machine = EM_S390;
463         ehdr->e_version = EV_CURRENT;
464         ehdr->e_phoff = sizeof(Elf64_Ehdr);
465         ehdr->e_ehsize = sizeof(Elf64_Ehdr);
466         ehdr->e_phentsize = sizeof(Elf64_Phdr);
467         ehdr->e_phnum = mem_chunk_cnt + 1;
468         return ehdr + 1;
469 }
470
471 /*
472  * Return CPU count for ELF header (new kernel)
473  */
474 static int get_cpu_cnt(void)
475 {
476         struct save_area *sa;
477         int cpus = 0;
478
479         list_for_each_entry(sa, &dump_save_areas, list)
480                 if (sa->prefix != 0)
481                         cpus++;
482         return cpus;
483 }
484
485 /*
486  * Return memory chunk count for ELF header (new kernel)
487  */
488 static int get_mem_chunk_cnt(void)
489 {
490         int cnt = 0;
491         u64 idx;
492
493         for_each_mem_range(idx, &memblock.physmem, &oldmem_type, NUMA_NO_NODE,
494                            MEMBLOCK_NONE, NULL, NULL, NULL)
495                 cnt++;
496         return cnt;
497 }
498
499 /*
500  * Initialize ELF loads (new kernel)
501  */
502 static void loads_init(Elf64_Phdr *phdr, u64 loads_offset)
503 {
504         phys_addr_t start, end;
505         u64 idx;
506
507         for_each_mem_range(idx, &memblock.physmem, &oldmem_type, NUMA_NO_NODE,
508                            MEMBLOCK_NONE, &start, &end, NULL) {
509                 phdr->p_filesz = end - start;
510                 phdr->p_type = PT_LOAD;
511                 phdr->p_offset = start;
512                 phdr->p_vaddr = start;
513                 phdr->p_paddr = start;
514                 phdr->p_memsz = end - start;
515                 phdr->p_flags = PF_R | PF_W | PF_X;
516                 phdr->p_align = PAGE_SIZE;
517                 phdr++;
518         }
519 }
520
521 /*
522  * Initialize notes (new kernel)
523  */
524 static void *notes_init(Elf64_Phdr *phdr, void *ptr, u64 notes_offset)
525 {
526         struct save_area *sa;
527         void *ptr_start = ptr;
528         int cpu;
529
530         ptr = nt_prpsinfo(ptr);
531
532         cpu = 1;
533         list_for_each_entry(sa, &dump_save_areas, list)
534                 if (sa->prefix != 0)
535                         ptr = fill_cpu_elf_notes(ptr, cpu++, sa);
536         ptr = nt_vmcoreinfo(ptr);
537         ptr = nt_final(ptr);
538         memset(phdr, 0, sizeof(*phdr));
539         phdr->p_type = PT_NOTE;
540         phdr->p_offset = notes_offset;
541         phdr->p_filesz = (unsigned long) PTR_SUB(ptr, ptr_start);
542         phdr->p_memsz = phdr->p_filesz;
543         return ptr;
544 }
545
546 /*
547  * Create ELF core header (new kernel)
548  */
549 int elfcorehdr_alloc(unsigned long long *addr, unsigned long long *size)
550 {
551         Elf64_Phdr *phdr_notes, *phdr_loads;
552         int mem_chunk_cnt;
553         void *ptr, *hdr;
554         u32 alloc_size;
555         u64 hdr_off;
556
557         /* If we are not in kdump or zfcpdump mode return */
558         if (!OLDMEM_BASE && ipl_info.type != IPL_TYPE_FCP_DUMP)
559                 return 0;
560         /* If we cannot get HSA size for zfcpdump return error */
561         if (ipl_info.type == IPL_TYPE_FCP_DUMP && !sclp.hsa_size)
562                 return -ENODEV;
563
564         /* For kdump, exclude previous crashkernel memory */
565         if (OLDMEM_BASE) {
566                 oldmem_region.base = OLDMEM_BASE;
567                 oldmem_region.size = OLDMEM_SIZE;
568                 oldmem_type.total_size = OLDMEM_SIZE;
569         }
570
571         mem_chunk_cnt = get_mem_chunk_cnt();
572
573         alloc_size = 0x1000 + get_cpu_cnt() * 0x4a0 +
574                 mem_chunk_cnt * sizeof(Elf64_Phdr);
575         hdr = kzalloc_panic(alloc_size);
576         /* Init elf header */
577         ptr = ehdr_init(hdr, mem_chunk_cnt);
578         /* Init program headers */
579         phdr_notes = ptr;
580         ptr = PTR_ADD(ptr, sizeof(Elf64_Phdr));
581         phdr_loads = ptr;
582         ptr = PTR_ADD(ptr, sizeof(Elf64_Phdr) * mem_chunk_cnt);
583         /* Init notes */
584         hdr_off = PTR_DIFF(ptr, hdr);
585         ptr = notes_init(phdr_notes, ptr, ((unsigned long) hdr) + hdr_off);
586         /* Init loads */
587         hdr_off = PTR_DIFF(ptr, hdr);
588         loads_init(phdr_loads, hdr_off);
589         *addr = (unsigned long long) hdr;
590         *size = (unsigned long long) hdr_off;
591         BUG_ON(elfcorehdr_size > alloc_size);
592         return 0;
593 }
594
595 /*
596  * Free ELF core header (new kernel)
597  */
598 void elfcorehdr_free(unsigned long long addr)
599 {
600         kfree((void *)(unsigned long)addr);
601 }
602
603 /*
604  * Read from ELF header
605  */
606 ssize_t elfcorehdr_read(char *buf, size_t count, u64 *ppos)
607 {
608         void *src = (void *)(unsigned long)*ppos;
609
610         memcpy(buf, src, count);
611         *ppos += count;
612         return count;
613 }
614
615 /*
616  * Read from ELF notes data
617  */
618 ssize_t elfcorehdr_read_notes(char *buf, size_t count, u64 *ppos)
619 {
620         void *src = (void *)(unsigned long)*ppos;
621
622         memcpy(buf, src, count);
623         *ppos += count;
624         return count;
625 }