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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
27static struct memblock_region oldmem_region;
28
29static struct memblock_type oldmem_type = {
30 .cnt = 1,
31 .max = 1,
32 .total_size = 0,
33 .regions = &oldmem_region,
34};
35
36struct 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
52static LIST_HEAD(dump_save_areas);
53
54/*
55 * Allocate a save area
56 */
57struct 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 */
72struct 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 */
80void __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 */
100void __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 */
114static 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 */
130int 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 */
174static 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 */
212ssize_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 */
234static 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 */
261static 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 */
283int 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 */
296static 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 */
309static 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
330static 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 */
342static 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 */
377static 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 */
390static 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(¬e, 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") != 0)
405 return NULL;
406 vmcoreinfo = kzalloc_panic(note.n_descsz);
407 if (copy_oldmem_kernel(vmcoreinfo, addr + 24, note.n_descsz))
408 return NULL;
409 *size = note.n_descsz;
410 return vmcoreinfo;
411}
412
413/*
414 * Initialize vmcoreinfo note (new kernel)
415 */
416static void *nt_vmcoreinfo(void *ptr)
417{
418 unsigned long size;
419 void *vmcoreinfo;
420
421 vmcoreinfo = os_info_old_entry(OS_INFO_VMCOREINFO, &size);
422 if (!vmcoreinfo)
423 vmcoreinfo = get_vmcoreinfo_old(&size);
424 if (!vmcoreinfo)
425 return ptr;
426 return nt_init_name(ptr, 0, vmcoreinfo, size, "VMCOREINFO");
427}
428
429/*
430 * Initialize ELF header (new kernel)
431 */
432static void *ehdr_init(Elf64_Ehdr *ehdr, int mem_chunk_cnt)
433{
434 memset(ehdr, 0, sizeof(*ehdr));
435 memcpy(ehdr->e_ident, ELFMAG, SELFMAG);
436 ehdr->e_ident[EI_CLASS] = ELFCLASS64;
437 ehdr->e_ident[EI_DATA] = ELFDATA2MSB;
438 ehdr->e_ident[EI_VERSION] = EV_CURRENT;
439 memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD);
440 ehdr->e_type = ET_CORE;
441 ehdr->e_machine = EM_S390;
442 ehdr->e_version = EV_CURRENT;
443 ehdr->e_phoff = sizeof(Elf64_Ehdr);
444 ehdr->e_ehsize = sizeof(Elf64_Ehdr);
445 ehdr->e_phentsize = sizeof(Elf64_Phdr);
446 ehdr->e_phnum = mem_chunk_cnt + 1;
447 return ehdr + 1;
448}
449
450/*
451 * Return CPU count for ELF header (new kernel)
452 */
453static int get_cpu_cnt(void)
454{
455 struct save_area *sa;
456 int cpus = 0;
457
458 list_for_each_entry(sa, &dump_save_areas, list)
459 if (sa->prefix != 0)
460 cpus++;
461 return cpus;
462}
463
464/*
465 * Return memory chunk count for ELF header (new kernel)
466 */
467static int get_mem_chunk_cnt(void)
468{
469 int cnt = 0;
470 u64 idx;
471
472 for_each_mem_range(idx, &memblock.physmem, &oldmem_type, NUMA_NO_NODE,
473 MEMBLOCK_NONE, NULL, NULL, NULL)
474 cnt++;
475 return cnt;
476}
477
478/*
479 * Initialize ELF loads (new kernel)
480 */
481static void loads_init(Elf64_Phdr *phdr, u64 loads_offset)
482{
483 phys_addr_t start, end;
484 u64 idx;
485
486 for_each_mem_range(idx, &memblock.physmem, &oldmem_type, NUMA_NO_NODE,
487 MEMBLOCK_NONE, &start, &end, NULL) {
488 phdr->p_filesz = end - start;
489 phdr->p_type = PT_LOAD;
490 phdr->p_offset = start;
491 phdr->p_vaddr = start;
492 phdr->p_paddr = start;
493 phdr->p_memsz = end - start;
494 phdr->p_flags = PF_R | PF_W | PF_X;
495 phdr->p_align = PAGE_SIZE;
496 phdr++;
497 }
498}
499
500/*
501 * Initialize notes (new kernel)
502 */
503static void *notes_init(Elf64_Phdr *phdr, void *ptr, u64 notes_offset)
504{
505 struct save_area *sa;
506 void *ptr_start = ptr;
507 int cpu;
508
509 ptr = nt_prpsinfo(ptr);
510
511 cpu = 1;
512 list_for_each_entry(sa, &dump_save_areas, list)
513 if (sa->prefix != 0)
514 ptr = fill_cpu_elf_notes(ptr, cpu++, sa);
515 ptr = nt_vmcoreinfo(ptr);
516 memset(phdr, 0, sizeof(*phdr));
517 phdr->p_type = PT_NOTE;
518 phdr->p_offset = notes_offset;
519 phdr->p_filesz = (unsigned long) PTR_SUB(ptr, ptr_start);
520 phdr->p_memsz = phdr->p_filesz;
521 return ptr;
522}
523
524/*
525 * Create ELF core header (new kernel)
526 */
527int elfcorehdr_alloc(unsigned long long *addr, unsigned long long *size)
528{
529 Elf64_Phdr *phdr_notes, *phdr_loads;
530 int mem_chunk_cnt;
531 void *ptr, *hdr;
532 u32 alloc_size;
533 u64 hdr_off;
534
535 /* If we are not in kdump or zfcpdump mode return */
536 if (!OLDMEM_BASE && ipl_info.type != IPL_TYPE_FCP_DUMP)
537 return 0;
538 /* If we cannot get HSA size for zfcpdump return error */
539 if (ipl_info.type == IPL_TYPE_FCP_DUMP && !sclp.hsa_size)
540 return -ENODEV;
541
542 /* For kdump, exclude previous crashkernel memory */
543 if (OLDMEM_BASE) {
544 oldmem_region.base = OLDMEM_BASE;
545 oldmem_region.size = OLDMEM_SIZE;
546 oldmem_type.total_size = OLDMEM_SIZE;
547 }
548
549 mem_chunk_cnt = get_mem_chunk_cnt();
550
551 alloc_size = 0x1000 + get_cpu_cnt() * 0x4a0 +
552 mem_chunk_cnt * sizeof(Elf64_Phdr);
553 hdr = kzalloc_panic(alloc_size);
554 /* Init elf header */
555 ptr = ehdr_init(hdr, mem_chunk_cnt);
556 /* Init program headers */
557 phdr_notes = ptr;
558 ptr = PTR_ADD(ptr, sizeof(Elf64_Phdr));
559 phdr_loads = ptr;
560 ptr = PTR_ADD(ptr, sizeof(Elf64_Phdr) * mem_chunk_cnt);
561 /* Init notes */
562 hdr_off = PTR_DIFF(ptr, hdr);
563 ptr = notes_init(phdr_notes, ptr, ((unsigned long) hdr) + hdr_off);
564 /* Init loads */
565 hdr_off = PTR_DIFF(ptr, hdr);
566 loads_init(phdr_loads, hdr_off);
567 *addr = (unsigned long long) hdr;
568 *size = (unsigned long long) hdr_off;
569 BUG_ON(elfcorehdr_size > alloc_size);
570 return 0;
571}
572
573/*
574 * Free ELF core header (new kernel)
575 */
576void elfcorehdr_free(unsigned long long addr)
577{
578 kfree((void *)(unsigned long)addr);
579}
580
581/*
582 * Read from ELF header
583 */
584ssize_t elfcorehdr_read(char *buf, size_t count, u64 *ppos)
585{
586 void *src = (void *)(unsigned long)*ppos;
587
588 memcpy(buf, src, count);
589 *ppos += count;
590 return count;
591}
592
593/*
594 * Read from ELF notes data
595 */
596ssize_t elfcorehdr_read_notes(char *buf, size_t count, u64 *ppos)
597{
598 void *src = (void *)(unsigned long)*ppos;
599
600 memcpy(buf, src, count);
601 *ppos += count;
602 return count;
603}