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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * S390 kdump implementation
4 *
5 * Copyright IBM Corp. 2011
6 * Author(s): Michael Holzheu <holzheu@linux.vnet.ibm.com>
7 */
8
9#include <linux/crash_dump.h>
10#include <asm/lowcore.h>
11#include <linux/kernel.h>
12#include <linux/init.h>
13#include <linux/mm.h>
14#include <linux/gfp.h>
15#include <linux/slab.h>
16#include <linux/bootmem.h>
17#include <linux/elf.h>
18#include <asm/asm-offsets.h>
19#include <linux/memblock.h>
20#include <asm/os_info.h>
21#include <asm/elf.h>
22#include <asm/ipl.h>
23#include <asm/sclp.h>
24
25#define PTR_ADD(x, y) (((char *) (x)) + ((unsigned long) (y)))
26#define PTR_SUB(x, y) (((char *) (x)) - ((unsigned long) (y)))
27#define PTR_DIFF(x, y) ((unsigned long)(((char *) (x)) - ((unsigned long) (y))))
28
29static struct memblock_region oldmem_region;
30
31static struct memblock_type oldmem_type = {
32 .cnt = 1,
33 .max = 1,
34 .total_size = 0,
35 .regions = &oldmem_region,
36 .name = "oldmem",
37};
38
39struct save_area {
40 struct list_head list;
41 u64 psw[2];
42 u64 ctrs[16];
43 u64 gprs[16];
44 u32 acrs[16];
45 u64 fprs[16];
46 u32 fpc;
47 u32 prefix;
48 u64 todpreg;
49 u64 timer;
50 u64 todcmp;
51 u64 vxrs_low[16];
52 __vector128 vxrs_high[16];
53};
54
55static LIST_HEAD(dump_save_areas);
56
57/*
58 * Allocate a save area
59 */
60struct save_area * __init save_area_alloc(bool is_boot_cpu)
61{
62 struct save_area *sa;
63
64 sa = (void *) memblock_alloc(sizeof(*sa), 8);
65 if (is_boot_cpu)
66 list_add(&sa->list, &dump_save_areas);
67 else
68 list_add_tail(&sa->list, &dump_save_areas);
69 return sa;
70}
71
72/*
73 * Return the address of the save area for the boot CPU
74 */
75struct save_area * __init save_area_boot_cpu(void)
76{
77 return list_first_entry_or_null(&dump_save_areas, struct save_area, list);
78}
79
80/*
81 * Copy CPU registers into the save area
82 */
83void __init save_area_add_regs(struct save_area *sa, void *regs)
84{
85 struct lowcore *lc;
86
87 lc = (struct lowcore *)(regs - __LC_FPREGS_SAVE_AREA);
88 memcpy(&sa->psw, &lc->psw_save_area, sizeof(sa->psw));
89 memcpy(&sa->ctrs, &lc->cregs_save_area, sizeof(sa->ctrs));
90 memcpy(&sa->gprs, &lc->gpregs_save_area, sizeof(sa->gprs));
91 memcpy(&sa->acrs, &lc->access_regs_save_area, sizeof(sa->acrs));
92 memcpy(&sa->fprs, &lc->floating_pt_save_area, sizeof(sa->fprs));
93 memcpy(&sa->fpc, &lc->fpt_creg_save_area, sizeof(sa->fpc));
94 memcpy(&sa->prefix, &lc->prefixreg_save_area, sizeof(sa->prefix));
95 memcpy(&sa->todpreg, &lc->tod_progreg_save_area, sizeof(sa->todpreg));
96 memcpy(&sa->timer, &lc->cpu_timer_save_area, sizeof(sa->timer));
97 memcpy(&sa->todcmp, &lc->clock_comp_save_area, sizeof(sa->todcmp));
98}
99
100/*
101 * Copy vector registers into the save area
102 */
103void __init save_area_add_vxrs(struct save_area *sa, __vector128 *vxrs)
104{
105 int i;
106
107 /* Copy lower halves of vector registers 0-15 */
108 for (i = 0; i < 16; i++)
109 memcpy(&sa->vxrs_low[i], &vxrs[i].u[2], 8);
110 /* Copy vector registers 16-31 */
111 memcpy(sa->vxrs_high, vxrs + 16, 16 * sizeof(__vector128));
112}
113
114/*
115 * Return physical address for virtual address
116 */
117static inline void *load_real_addr(void *addr)
118{
119 unsigned long real_addr;
120
121 asm volatile(
122 " lra %0,0(%1)\n"
123 " jz 0f\n"
124 " la %0,0\n"
125 "0:"
126 : "=a" (real_addr) : "a" (addr) : "cc");
127 return (void *)real_addr;
128}
129
130/*
131 * Copy memory of the old, dumped system to a kernel space virtual address
132 */
133int copy_oldmem_kernel(void *dst, void *src, size_t count)
134{
135 unsigned long from, len;
136 void *ra;
137 int rc;
138
139 while (count) {
140 from = __pa(src);
141 if (!OLDMEM_BASE && from < sclp.hsa_size) {
142 /* Copy from zfcpdump HSA area */
143 len = min(count, sclp.hsa_size - from);
144 rc = memcpy_hsa_kernel(dst, from, len);
145 if (rc)
146 return rc;
147 } else {
148 /* Check for swapped kdump oldmem areas */
149 if (OLDMEM_BASE && from - OLDMEM_BASE < OLDMEM_SIZE) {
150 from -= OLDMEM_BASE;
151 len = min(count, OLDMEM_SIZE - from);
152 } else if (OLDMEM_BASE && from < OLDMEM_SIZE) {
153 len = min(count, OLDMEM_SIZE - from);
154 from += OLDMEM_BASE;
155 } else {
156 len = count;
157 }
158 if (is_vmalloc_or_module_addr(dst)) {
159 ra = load_real_addr(dst);
160 len = min(PAGE_SIZE - offset_in_page(ra), len);
161 } else {
162 ra = dst;
163 }
164 if (memcpy_real(ra, (void *) from, len))
165 return -EFAULT;
166 }
167 dst += len;
168 src += len;
169 count -= len;
170 }
171 return 0;
172}
173
174/*
175 * Copy memory of the old, dumped system to a user space virtual address
176 */
177static int copy_oldmem_user(void __user *dst, void *src, size_t count)
178{
179 unsigned long from, len;
180 int rc;
181
182 while (count) {
183 from = __pa(src);
184 if (!OLDMEM_BASE && from < sclp.hsa_size) {
185 /* Copy from zfcpdump HSA area */
186 len = min(count, sclp.hsa_size - from);
187 rc = memcpy_hsa_user(dst, from, len);
188 if (rc)
189 return rc;
190 } else {
191 /* Check for swapped kdump oldmem areas */
192 if (OLDMEM_BASE && from - OLDMEM_BASE < OLDMEM_SIZE) {
193 from -= OLDMEM_BASE;
194 len = min(count, OLDMEM_SIZE - from);
195 } else if (OLDMEM_BASE && from < OLDMEM_SIZE) {
196 len = min(count, OLDMEM_SIZE - from);
197 from += OLDMEM_BASE;
198 } else {
199 len = count;
200 }
201 rc = copy_to_user_real(dst, (void *) from, count);
202 if (rc)
203 return rc;
204 }
205 dst += len;
206 src += len;
207 count -= len;
208 }
209 return 0;
210}
211
212/*
213 * Copy one page from "oldmem"
214 */
215ssize_t copy_oldmem_page(unsigned long pfn, char *buf, size_t csize,
216 unsigned long offset, int userbuf)
217{
218 void *src;
219 int rc;
220
221 if (!csize)
222 return 0;
223 src = (void *) (pfn << PAGE_SHIFT) + offset;
224 if (userbuf)
225 rc = copy_oldmem_user((void __force __user *) buf, src, csize);
226 else
227 rc = copy_oldmem_kernel((void *) buf, src, csize);
228 return rc;
229}
230
231/*
232 * Remap "oldmem" for kdump
233 *
234 * For the kdump reserved memory this functions performs a swap operation:
235 * [0 - OLDMEM_SIZE] is mapped to [OLDMEM_BASE - OLDMEM_BASE + OLDMEM_SIZE]
236 */
237static int remap_oldmem_pfn_range_kdump(struct vm_area_struct *vma,
238 unsigned long from, unsigned long pfn,
239 unsigned long size, pgprot_t prot)
240{
241 unsigned long size_old;
242 int rc;
243
244 if (pfn < OLDMEM_SIZE >> PAGE_SHIFT) {
245 size_old = min(size, OLDMEM_SIZE - (pfn << PAGE_SHIFT));
246 rc = remap_pfn_range(vma, from,
247 pfn + (OLDMEM_BASE >> PAGE_SHIFT),
248 size_old, prot);
249 if (rc || size == size_old)
250 return rc;
251 size -= size_old;
252 from += size_old;
253 pfn += size_old >> PAGE_SHIFT;
254 }
255 return remap_pfn_range(vma, from, pfn, size, prot);
256}
257
258/*
259 * Remap "oldmem" for zfcpdump
260 *
261 * We only map available memory above HSA size. Memory below HSA size
262 * is read on demand using the copy_oldmem_page() function.
263 */
264static int remap_oldmem_pfn_range_zfcpdump(struct vm_area_struct *vma,
265 unsigned long from,
266 unsigned long pfn,
267 unsigned long size, pgprot_t prot)
268{
269 unsigned long hsa_end = sclp.hsa_size;
270 unsigned long size_hsa;
271
272 if (pfn < hsa_end >> PAGE_SHIFT) {
273 size_hsa = min(size, hsa_end - (pfn << PAGE_SHIFT));
274 if (size == size_hsa)
275 return 0;
276 size -= size_hsa;
277 from += size_hsa;
278 pfn += size_hsa >> PAGE_SHIFT;
279 }
280 return remap_pfn_range(vma, from, pfn, size, prot);
281}
282
283/*
284 * Remap "oldmem" for kdump or zfcpdump
285 */
286int remap_oldmem_pfn_range(struct vm_area_struct *vma, unsigned long from,
287 unsigned long pfn, unsigned long size, pgprot_t prot)
288{
289 if (OLDMEM_BASE)
290 return remap_oldmem_pfn_range_kdump(vma, from, pfn, size, prot);
291 else
292 return remap_oldmem_pfn_range_zfcpdump(vma, from, pfn, size,
293 prot);
294}
295
296/*
297 * Alloc memory and panic in case of ENOMEM
298 */
299static void *kzalloc_panic(int len)
300{
301 void *rc;
302
303 rc = kzalloc(len, GFP_KERNEL);
304 if (!rc)
305 panic("s390 kdump kzalloc (%d) failed", len);
306 return rc;
307}
308
309/*
310 * Initialize ELF note
311 */
312static void *nt_init_name(void *buf, Elf64_Word type, void *desc, int d_len,
313 const char *name)
314{
315 Elf64_Nhdr *note;
316 u64 len;
317
318 note = (Elf64_Nhdr *)buf;
319 note->n_namesz = strlen(name) + 1;
320 note->n_descsz = d_len;
321 note->n_type = type;
322 len = sizeof(Elf64_Nhdr);
323
324 memcpy(buf + len, name, note->n_namesz);
325 len = roundup(len + note->n_namesz, 4);
326
327 memcpy(buf + len, desc, note->n_descsz);
328 len = roundup(len + note->n_descsz, 4);
329
330 return PTR_ADD(buf, len);
331}
332
333static inline void *nt_init(void *buf, Elf64_Word type, void *desc, int d_len)
334{
335 const char *note_name = "LINUX";
336
337 if (type == NT_PRPSINFO || type == NT_PRSTATUS || type == NT_PRFPREG)
338 note_name = KEXEC_CORE_NOTE_NAME;
339 return nt_init_name(buf, type, desc, d_len, note_name);
340}
341
342/*
343 * Fill ELF notes for one CPU with save area registers
344 */
345static void *fill_cpu_elf_notes(void *ptr, int cpu, struct save_area *sa)
346{
347 struct elf_prstatus nt_prstatus;
348 elf_fpregset_t nt_fpregset;
349
350 /* Prepare prstatus note */
351 memset(&nt_prstatus, 0, sizeof(nt_prstatus));
352 memcpy(&nt_prstatus.pr_reg.gprs, sa->gprs, sizeof(sa->gprs));
353 memcpy(&nt_prstatus.pr_reg.psw, sa->psw, sizeof(sa->psw));
354 memcpy(&nt_prstatus.pr_reg.acrs, sa->acrs, sizeof(sa->acrs));
355 nt_prstatus.pr_pid = cpu;
356 /* Prepare fpregset (floating point) note */
357 memset(&nt_fpregset, 0, sizeof(nt_fpregset));
358 memcpy(&nt_fpregset.fpc, &sa->fpc, sizeof(sa->fpc));
359 memcpy(&nt_fpregset.fprs, &sa->fprs, sizeof(sa->fprs));
360 /* Create ELF notes for the CPU */
361 ptr = nt_init(ptr, NT_PRSTATUS, &nt_prstatus, sizeof(nt_prstatus));
362 ptr = nt_init(ptr, NT_PRFPREG, &nt_fpregset, sizeof(nt_fpregset));
363 ptr = nt_init(ptr, NT_S390_TIMER, &sa->timer, sizeof(sa->timer));
364 ptr = nt_init(ptr, NT_S390_TODCMP, &sa->todcmp, sizeof(sa->todcmp));
365 ptr = nt_init(ptr, NT_S390_TODPREG, &sa->todpreg, sizeof(sa->todpreg));
366 ptr = nt_init(ptr, NT_S390_CTRS, &sa->ctrs, sizeof(sa->ctrs));
367 ptr = nt_init(ptr, NT_S390_PREFIX, &sa->prefix, sizeof(sa->prefix));
368 if (MACHINE_HAS_VX) {
369 ptr = nt_init(ptr, NT_S390_VXRS_HIGH,
370 &sa->vxrs_high, sizeof(sa->vxrs_high));
371 ptr = nt_init(ptr, NT_S390_VXRS_LOW,
372 &sa->vxrs_low, sizeof(sa->vxrs_low));
373 }
374 return ptr;
375}
376
377/*
378 * Initialize prpsinfo note (new kernel)
379 */
380static void *nt_prpsinfo(void *ptr)
381{
382 struct elf_prpsinfo prpsinfo;
383
384 memset(&prpsinfo, 0, sizeof(prpsinfo));
385 prpsinfo.pr_sname = 'R';
386 strcpy(prpsinfo.pr_fname, "vmlinux");
387 return nt_init(ptr, NT_PRPSINFO, &prpsinfo, sizeof(prpsinfo));
388}
389
390/*
391 * Get vmcoreinfo using lowcore->vmcore_info (new kernel)
392 */
393static void *get_vmcoreinfo_old(unsigned long *size)
394{
395 char nt_name[11], *vmcoreinfo;
396 Elf64_Nhdr note;
397 void *addr;
398
399 if (copy_oldmem_kernel(&addr, &S390_lowcore.vmcore_info, sizeof(addr)))
400 return NULL;
401 memset(nt_name, 0, sizeof(nt_name));
402 if (copy_oldmem_kernel(¬e, addr, sizeof(note)))
403 return NULL;
404 if (copy_oldmem_kernel(nt_name, addr + sizeof(note),
405 sizeof(nt_name) - 1))
406 return NULL;
407 if (strcmp(nt_name, "VMCOREINFO") != 0)
408 return NULL;
409 vmcoreinfo = kzalloc_panic(note.n_descsz);
410 if (copy_oldmem_kernel(vmcoreinfo, addr + 24, note.n_descsz))
411 return NULL;
412 *size = note.n_descsz;
413 return vmcoreinfo;
414}
415
416/*
417 * Initialize vmcoreinfo note (new kernel)
418 */
419static void *nt_vmcoreinfo(void *ptr)
420{
421 unsigned long size;
422 void *vmcoreinfo;
423
424 vmcoreinfo = os_info_old_entry(OS_INFO_VMCOREINFO, &size);
425 if (!vmcoreinfo)
426 vmcoreinfo = get_vmcoreinfo_old(&size);
427 if (!vmcoreinfo)
428 return ptr;
429 return nt_init_name(ptr, 0, vmcoreinfo, size, "VMCOREINFO");
430}
431
432/*
433 * Initialize final note (needed for /proc/vmcore code)
434 */
435static void *nt_final(void *ptr)
436{
437 Elf64_Nhdr *note;
438
439 note = (Elf64_Nhdr *) ptr;
440 note->n_namesz = 0;
441 note->n_descsz = 0;
442 note->n_type = 0;
443 return PTR_ADD(ptr, sizeof(Elf64_Nhdr));
444}
445
446/*
447 * Initialize ELF header (new kernel)
448 */
449static void *ehdr_init(Elf64_Ehdr *ehdr, int mem_chunk_cnt)
450{
451 memset(ehdr, 0, sizeof(*ehdr));
452 memcpy(ehdr->e_ident, ELFMAG, SELFMAG);
453 ehdr->e_ident[EI_CLASS] = ELFCLASS64;
454 ehdr->e_ident[EI_DATA] = ELFDATA2MSB;
455 ehdr->e_ident[EI_VERSION] = EV_CURRENT;
456 memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD);
457 ehdr->e_type = ET_CORE;
458 ehdr->e_machine = EM_S390;
459 ehdr->e_version = EV_CURRENT;
460 ehdr->e_phoff = sizeof(Elf64_Ehdr);
461 ehdr->e_ehsize = sizeof(Elf64_Ehdr);
462 ehdr->e_phentsize = sizeof(Elf64_Phdr);
463 ehdr->e_phnum = mem_chunk_cnt + 1;
464 return ehdr + 1;
465}
466
467/*
468 * Return CPU count for ELF header (new kernel)
469 */
470static int get_cpu_cnt(void)
471{
472 struct save_area *sa;
473 int cpus = 0;
474
475 list_for_each_entry(sa, &dump_save_areas, list)
476 if (sa->prefix != 0)
477 cpus++;
478 return cpus;
479}
480
481/*
482 * Return memory chunk count for ELF header (new kernel)
483 */
484static int get_mem_chunk_cnt(void)
485{
486 int cnt = 0;
487 u64 idx;
488
489 for_each_mem_range(idx, &memblock.physmem, &oldmem_type, NUMA_NO_NODE,
490 MEMBLOCK_NONE, NULL, NULL, NULL)
491 cnt++;
492 return cnt;
493}
494
495/*
496 * Initialize ELF loads (new kernel)
497 */
498static void loads_init(Elf64_Phdr *phdr, u64 loads_offset)
499{
500 phys_addr_t start, end;
501 u64 idx;
502
503 for_each_mem_range(idx, &memblock.physmem, &oldmem_type, NUMA_NO_NODE,
504 MEMBLOCK_NONE, &start, &end, NULL) {
505 phdr->p_filesz = end - start;
506 phdr->p_type = PT_LOAD;
507 phdr->p_offset = start;
508 phdr->p_vaddr = start;
509 phdr->p_paddr = start;
510 phdr->p_memsz = end - start;
511 phdr->p_flags = PF_R | PF_W | PF_X;
512 phdr->p_align = PAGE_SIZE;
513 phdr++;
514 }
515}
516
517/*
518 * Initialize notes (new kernel)
519 */
520static void *notes_init(Elf64_Phdr *phdr, void *ptr, u64 notes_offset)
521{
522 struct save_area *sa;
523 void *ptr_start = ptr;
524 int cpu;
525
526 ptr = nt_prpsinfo(ptr);
527
528 cpu = 1;
529 list_for_each_entry(sa, &dump_save_areas, list)
530 if (sa->prefix != 0)
531 ptr = fill_cpu_elf_notes(ptr, cpu++, sa);
532 ptr = nt_vmcoreinfo(ptr);
533 ptr = nt_final(ptr);
534 memset(phdr, 0, sizeof(*phdr));
535 phdr->p_type = PT_NOTE;
536 phdr->p_offset = notes_offset;
537 phdr->p_filesz = (unsigned long) PTR_SUB(ptr, ptr_start);
538 phdr->p_memsz = phdr->p_filesz;
539 return ptr;
540}
541
542/*
543 * Create ELF core header (new kernel)
544 */
545int elfcorehdr_alloc(unsigned long long *addr, unsigned long long *size)
546{
547 Elf64_Phdr *phdr_notes, *phdr_loads;
548 int mem_chunk_cnt;
549 void *ptr, *hdr;
550 u32 alloc_size;
551 u64 hdr_off;
552
553 /* If we are not in kdump or zfcpdump mode return */
554 if (!OLDMEM_BASE && ipl_info.type != IPL_TYPE_FCP_DUMP)
555 return 0;
556 /* If we cannot get HSA size for zfcpdump return error */
557 if (ipl_info.type == IPL_TYPE_FCP_DUMP && !sclp.hsa_size)
558 return -ENODEV;
559
560 /* For kdump, exclude previous crashkernel memory */
561 if (OLDMEM_BASE) {
562 oldmem_region.base = OLDMEM_BASE;
563 oldmem_region.size = OLDMEM_SIZE;
564 oldmem_type.total_size = OLDMEM_SIZE;
565 }
566
567 mem_chunk_cnt = get_mem_chunk_cnt();
568
569 alloc_size = 0x1000 + get_cpu_cnt() * 0x4a0 +
570 mem_chunk_cnt * sizeof(Elf64_Phdr);
571 hdr = kzalloc_panic(alloc_size);
572 /* Init elf header */
573 ptr = ehdr_init(hdr, mem_chunk_cnt);
574 /* Init program headers */
575 phdr_notes = ptr;
576 ptr = PTR_ADD(ptr, sizeof(Elf64_Phdr));
577 phdr_loads = ptr;
578 ptr = PTR_ADD(ptr, sizeof(Elf64_Phdr) * mem_chunk_cnt);
579 /* Init notes */
580 hdr_off = PTR_DIFF(ptr, hdr);
581 ptr = notes_init(phdr_notes, ptr, ((unsigned long) hdr) + hdr_off);
582 /* Init loads */
583 hdr_off = PTR_DIFF(ptr, hdr);
584 loads_init(phdr_loads, hdr_off);
585 *addr = (unsigned long long) hdr;
586 *size = (unsigned long long) hdr_off;
587 BUG_ON(elfcorehdr_size > alloc_size);
588 return 0;
589}
590
591/*
592 * Free ELF core header (new kernel)
593 */
594void elfcorehdr_free(unsigned long long addr)
595{
596 kfree((void *)(unsigned long)addr);
597}
598
599/*
600 * Read from ELF header
601 */
602ssize_t elfcorehdr_read(char *buf, size_t count, u64 *ppos)
603{
604 void *src = (void *)(unsigned long)*ppos;
605
606 memcpy(buf, src, count);
607 *ppos += count;
608 return count;
609}
610
611/*
612 * Read from ELF notes data
613 */
614ssize_t elfcorehdr_read_notes(char *buf, size_t count, u64 *ppos)
615{
616 void *src = (void *)(unsigned long)*ppos;
617
618 memcpy(buf, src, count);
619 *ppos += count;
620 return count;
621}