1 // SPDX-License-Identifier: GPL-2.0
3 * S390 kdump implementation
5 * Copyright IBM Corp. 2011
6 * Author(s): Michael Holzheu <holzheu@linux.vnet.ibm.com>
9 #include <linux/crash_dump.h>
10 #include <asm/lowcore.h>
11 #include <linux/kernel.h>
12 #include <linux/init.h>
14 #include <linux/gfp.h>
15 #include <linux/slab.h>
16 #include <linux/memblock.h>
17 #include <linux/elf.h>
18 #include <asm/asm-offsets.h>
19 #include <asm/os_info.h>
24 #define PTR_ADD(x, y) (((char *) (x)) + ((unsigned long) (y)))
25 #define PTR_SUB(x, y) (((char *) (x)) - ((unsigned long) (y)))
26 #define PTR_DIFF(x, y) ((unsigned long)(((char *) (x)) - ((unsigned long) (y))))
28 static struct memblock_region oldmem_region;
30 static struct memblock_type oldmem_type = {
34 .regions = &oldmem_region,
39 struct list_head list;
51 __vector128 vxrs_high[16];
54 static LIST_HEAD(dump_save_areas);
57 * Allocate a save area
59 struct save_area * __init save_area_alloc(bool is_boot_cpu)
63 sa = (void *) memblock_phys_alloc(sizeof(*sa), 8);
65 list_add(&sa->list, &dump_save_areas);
67 list_add_tail(&sa->list, &dump_save_areas);
72 * Return the address of the save area for the boot CPU
74 struct save_area * __init save_area_boot_cpu(void)
76 return list_first_entry_or_null(&dump_save_areas, struct save_area, list);
80 * Copy CPU registers into the save area
82 void __init save_area_add_regs(struct save_area *sa, void *regs)
86 lc = (struct lowcore *)(regs - __LC_FPREGS_SAVE_AREA);
87 memcpy(&sa->psw, &lc->psw_save_area, sizeof(sa->psw));
88 memcpy(&sa->ctrs, &lc->cregs_save_area, sizeof(sa->ctrs));
89 memcpy(&sa->gprs, &lc->gpregs_save_area, sizeof(sa->gprs));
90 memcpy(&sa->acrs, &lc->access_regs_save_area, sizeof(sa->acrs));
91 memcpy(&sa->fprs, &lc->floating_pt_save_area, sizeof(sa->fprs));
92 memcpy(&sa->fpc, &lc->fpt_creg_save_area, sizeof(sa->fpc));
93 memcpy(&sa->prefix, &lc->prefixreg_save_area, sizeof(sa->prefix));
94 memcpy(&sa->todpreg, &lc->tod_progreg_save_area, sizeof(sa->todpreg));
95 memcpy(&sa->timer, &lc->cpu_timer_save_area, sizeof(sa->timer));
96 memcpy(&sa->todcmp, &lc->clock_comp_save_area, sizeof(sa->todcmp));
100 * Copy vector registers into the save area
102 void __init save_area_add_vxrs(struct save_area *sa, __vector128 *vxrs)
106 /* Copy lower halves of vector registers 0-15 */
107 for (i = 0; i < 16; i++)
108 memcpy(&sa->vxrs_low[i], &vxrs[i].u[2], 8);
109 /* Copy vector registers 16-31 */
110 memcpy(sa->vxrs_high, vxrs + 16, 16 * sizeof(__vector128));
114 * Return physical address for virtual address
116 static inline void *load_real_addr(void *addr)
118 unsigned long real_addr;
125 : "=a" (real_addr) : "a" (addr) : "cc");
126 return (void *)real_addr;
130 * Copy memory of the old, dumped system to a kernel space virtual address
132 int copy_oldmem_kernel(void *dst, void *src, size_t count)
134 unsigned long from, len;
140 if (!OLDMEM_BASE && from < sclp.hsa_size) {
141 /* Copy from zfcpdump HSA area */
142 len = min(count, sclp.hsa_size - from);
143 rc = memcpy_hsa_kernel(dst, from, len);
147 /* Check for swapped kdump oldmem areas */
148 if (OLDMEM_BASE && from - OLDMEM_BASE < OLDMEM_SIZE) {
150 len = min(count, OLDMEM_SIZE - from);
151 } else if (OLDMEM_BASE && from < OLDMEM_SIZE) {
152 len = min(count, OLDMEM_SIZE - from);
157 if (is_vmalloc_or_module_addr(dst)) {
158 ra = load_real_addr(dst);
159 len = min(PAGE_SIZE - offset_in_page(ra), len);
163 if (memcpy_real(ra, (void *) from, len))
174 * Copy memory of the old, dumped system to a user space virtual address
176 static int copy_oldmem_user(void __user *dst, void *src, size_t count)
178 unsigned long from, len;
183 if (!OLDMEM_BASE && from < sclp.hsa_size) {
184 /* Copy from zfcpdump HSA area */
185 len = min(count, sclp.hsa_size - from);
186 rc = memcpy_hsa_user(dst, from, len);
190 /* Check for swapped kdump oldmem areas */
191 if (OLDMEM_BASE && from - OLDMEM_BASE < OLDMEM_SIZE) {
193 len = min(count, OLDMEM_SIZE - from);
194 } else if (OLDMEM_BASE && from < OLDMEM_SIZE) {
195 len = min(count, OLDMEM_SIZE - from);
200 rc = copy_to_user_real(dst, (void *) from, count);
212 * Copy one page from "oldmem"
214 ssize_t copy_oldmem_page(unsigned long pfn, char *buf, size_t csize,
215 unsigned long offset, int userbuf)
222 src = (void *) (pfn << PAGE_SHIFT) + offset;
224 rc = copy_oldmem_user((void __force __user *) buf, src, csize);
226 rc = copy_oldmem_kernel((void *) buf, src, csize);
231 * Remap "oldmem" for kdump
233 * For the kdump reserved memory this functions performs a swap operation:
234 * [0 - OLDMEM_SIZE] is mapped to [OLDMEM_BASE - OLDMEM_BASE + OLDMEM_SIZE]
236 static int remap_oldmem_pfn_range_kdump(struct vm_area_struct *vma,
237 unsigned long from, unsigned long pfn,
238 unsigned long size, pgprot_t prot)
240 unsigned long size_old;
243 if (pfn < OLDMEM_SIZE >> PAGE_SHIFT) {
244 size_old = min(size, OLDMEM_SIZE - (pfn << PAGE_SHIFT));
245 rc = remap_pfn_range(vma, from,
246 pfn + (OLDMEM_BASE >> PAGE_SHIFT),
248 if (rc || size == size_old)
252 pfn += size_old >> PAGE_SHIFT;
254 return remap_pfn_range(vma, from, pfn, size, prot);
258 * Remap "oldmem" for zfcpdump
260 * We only map available memory above HSA size. Memory below HSA size
261 * is read on demand using the copy_oldmem_page() function.
263 static int remap_oldmem_pfn_range_zfcpdump(struct vm_area_struct *vma,
266 unsigned long size, pgprot_t prot)
268 unsigned long hsa_end = sclp.hsa_size;
269 unsigned long size_hsa;
271 if (pfn < hsa_end >> PAGE_SHIFT) {
272 size_hsa = min(size, hsa_end - (pfn << PAGE_SHIFT));
273 if (size == size_hsa)
277 pfn += size_hsa >> PAGE_SHIFT;
279 return remap_pfn_range(vma, from, pfn, size, prot);
283 * Remap "oldmem" for kdump or zfcpdump
285 int remap_oldmem_pfn_range(struct vm_area_struct *vma, unsigned long from,
286 unsigned long pfn, unsigned long size, pgprot_t prot)
289 return remap_oldmem_pfn_range_kdump(vma, from, pfn, size, prot);
291 return remap_oldmem_pfn_range_zfcpdump(vma, from, pfn, size,
295 static const char *nt_name(Elf64_Word type)
297 const char *name = "LINUX";
299 if (type == NT_PRPSINFO || type == NT_PRSTATUS || type == NT_PRFPREG)
300 name = KEXEC_CORE_NOTE_NAME;
305 * Initialize ELF note
307 static void *nt_init_name(void *buf, Elf64_Word type, void *desc, int d_len,
313 note = (Elf64_Nhdr *)buf;
314 note->n_namesz = strlen(name) + 1;
315 note->n_descsz = d_len;
317 len = sizeof(Elf64_Nhdr);
319 memcpy(buf + len, name, note->n_namesz);
320 len = roundup(len + note->n_namesz, 4);
322 memcpy(buf + len, desc, note->n_descsz);
323 len = roundup(len + note->n_descsz, 4);
325 return PTR_ADD(buf, len);
328 static inline void *nt_init(void *buf, Elf64_Word type, void *desc, int d_len)
330 return nt_init_name(buf, type, desc, d_len, nt_name(type));
334 * Calculate the size of ELF note
336 static size_t nt_size_name(int d_len, const char *name)
340 size = sizeof(Elf64_Nhdr);
341 size += roundup(strlen(name) + 1, 4);
342 size += roundup(d_len, 4);
347 static inline size_t nt_size(Elf64_Word type, int d_len)
349 return nt_size_name(d_len, nt_name(type));
353 * Fill ELF notes for one CPU with save area registers
355 static void *fill_cpu_elf_notes(void *ptr, int cpu, struct save_area *sa)
357 struct elf_prstatus nt_prstatus;
358 elf_fpregset_t nt_fpregset;
360 /* Prepare prstatus note */
361 memset(&nt_prstatus, 0, sizeof(nt_prstatus));
362 memcpy(&nt_prstatus.pr_reg.gprs, sa->gprs, sizeof(sa->gprs));
363 memcpy(&nt_prstatus.pr_reg.psw, sa->psw, sizeof(sa->psw));
364 memcpy(&nt_prstatus.pr_reg.acrs, sa->acrs, sizeof(sa->acrs));
365 nt_prstatus.pr_pid = cpu;
366 /* Prepare fpregset (floating point) note */
367 memset(&nt_fpregset, 0, sizeof(nt_fpregset));
368 memcpy(&nt_fpregset.fpc, &sa->fpc, sizeof(sa->fpc));
369 memcpy(&nt_fpregset.fprs, &sa->fprs, sizeof(sa->fprs));
370 /* Create ELF notes for the CPU */
371 ptr = nt_init(ptr, NT_PRSTATUS, &nt_prstatus, sizeof(nt_prstatus));
372 ptr = nt_init(ptr, NT_PRFPREG, &nt_fpregset, sizeof(nt_fpregset));
373 ptr = nt_init(ptr, NT_S390_TIMER, &sa->timer, sizeof(sa->timer));
374 ptr = nt_init(ptr, NT_S390_TODCMP, &sa->todcmp, sizeof(sa->todcmp));
375 ptr = nt_init(ptr, NT_S390_TODPREG, &sa->todpreg, sizeof(sa->todpreg));
376 ptr = nt_init(ptr, NT_S390_CTRS, &sa->ctrs, sizeof(sa->ctrs));
377 ptr = nt_init(ptr, NT_S390_PREFIX, &sa->prefix, sizeof(sa->prefix));
378 if (MACHINE_HAS_VX) {
379 ptr = nt_init(ptr, NT_S390_VXRS_HIGH,
380 &sa->vxrs_high, sizeof(sa->vxrs_high));
381 ptr = nt_init(ptr, NT_S390_VXRS_LOW,
382 &sa->vxrs_low, sizeof(sa->vxrs_low));
388 * Calculate size of ELF notes per cpu
390 static size_t get_cpu_elf_notes_size(void)
392 struct save_area *sa = NULL;
395 size = nt_size(NT_PRSTATUS, sizeof(struct elf_prstatus));
396 size += nt_size(NT_PRFPREG, sizeof(elf_fpregset_t));
397 size += nt_size(NT_S390_TIMER, sizeof(sa->timer));
398 size += nt_size(NT_S390_TODCMP, sizeof(sa->todcmp));
399 size += nt_size(NT_S390_TODPREG, sizeof(sa->todpreg));
400 size += nt_size(NT_S390_CTRS, sizeof(sa->ctrs));
401 size += nt_size(NT_S390_PREFIX, sizeof(sa->prefix));
402 if (MACHINE_HAS_VX) {
403 size += nt_size(NT_S390_VXRS_HIGH, sizeof(sa->vxrs_high));
404 size += nt_size(NT_S390_VXRS_LOW, sizeof(sa->vxrs_low));
411 * Initialize prpsinfo note (new kernel)
413 static void *nt_prpsinfo(void *ptr)
415 struct elf_prpsinfo prpsinfo;
417 memset(&prpsinfo, 0, sizeof(prpsinfo));
418 prpsinfo.pr_sname = 'R';
419 strcpy(prpsinfo.pr_fname, "vmlinux");
420 return nt_init(ptr, NT_PRPSINFO, &prpsinfo, sizeof(prpsinfo));
424 * Get vmcoreinfo using lowcore->vmcore_info (new kernel)
426 static void *get_vmcoreinfo_old(unsigned long *size)
428 char nt_name[11], *vmcoreinfo;
432 if (copy_oldmem_kernel(&addr, &S390_lowcore.vmcore_info, sizeof(addr)))
434 memset(nt_name, 0, sizeof(nt_name));
435 if (copy_oldmem_kernel(¬e, addr, sizeof(note)))
437 if (copy_oldmem_kernel(nt_name, addr + sizeof(note),
438 sizeof(nt_name) - 1))
440 if (strcmp(nt_name, VMCOREINFO_NOTE_NAME) != 0)
442 vmcoreinfo = kzalloc(note.n_descsz, GFP_KERNEL);
445 if (copy_oldmem_kernel(vmcoreinfo, addr + 24, note.n_descsz)) {
449 *size = note.n_descsz;
454 * Initialize vmcoreinfo note (new kernel)
456 static void *nt_vmcoreinfo(void *ptr)
458 const char *name = VMCOREINFO_NOTE_NAME;
462 vmcoreinfo = os_info_old_entry(OS_INFO_VMCOREINFO, &size);
464 return nt_init_name(ptr, 0, vmcoreinfo, size, name);
466 vmcoreinfo = get_vmcoreinfo_old(&size);
469 ptr = nt_init_name(ptr, 0, vmcoreinfo, size, name);
474 static size_t nt_vmcoreinfo_size(void)
476 const char *name = VMCOREINFO_NOTE_NAME;
480 vmcoreinfo = os_info_old_entry(OS_INFO_VMCOREINFO, &size);
482 return nt_size_name(size, name);
484 vmcoreinfo = get_vmcoreinfo_old(&size);
489 return nt_size_name(size, name);
493 * Initialize final note (needed for /proc/vmcore code)
495 static void *nt_final(void *ptr)
499 note = (Elf64_Nhdr *) ptr;
503 return PTR_ADD(ptr, sizeof(Elf64_Nhdr));
507 * Initialize ELF header (new kernel)
509 static void *ehdr_init(Elf64_Ehdr *ehdr, int mem_chunk_cnt)
511 memset(ehdr, 0, sizeof(*ehdr));
512 memcpy(ehdr->e_ident, ELFMAG, SELFMAG);
513 ehdr->e_ident[EI_CLASS] = ELFCLASS64;
514 ehdr->e_ident[EI_DATA] = ELFDATA2MSB;
515 ehdr->e_ident[EI_VERSION] = EV_CURRENT;
516 memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD);
517 ehdr->e_type = ET_CORE;
518 ehdr->e_machine = EM_S390;
519 ehdr->e_version = EV_CURRENT;
520 ehdr->e_phoff = sizeof(Elf64_Ehdr);
521 ehdr->e_ehsize = sizeof(Elf64_Ehdr);
522 ehdr->e_phentsize = sizeof(Elf64_Phdr);
523 ehdr->e_phnum = mem_chunk_cnt + 1;
528 * Return CPU count for ELF header (new kernel)
530 static int get_cpu_cnt(void)
532 struct save_area *sa;
535 list_for_each_entry(sa, &dump_save_areas, list)
542 * Return memory chunk count for ELF header (new kernel)
544 static int get_mem_chunk_cnt(void)
549 for_each_mem_range(idx, &memblock.physmem, &oldmem_type, NUMA_NO_NODE,
550 MEMBLOCK_NONE, NULL, NULL, NULL)
556 * Initialize ELF loads (new kernel)
558 static void loads_init(Elf64_Phdr *phdr, u64 loads_offset)
560 phys_addr_t start, end;
563 for_each_mem_range(idx, &memblock.physmem, &oldmem_type, NUMA_NO_NODE,
564 MEMBLOCK_NONE, &start, &end, NULL) {
565 phdr->p_filesz = end - start;
566 phdr->p_type = PT_LOAD;
567 phdr->p_offset = start;
568 phdr->p_vaddr = start;
569 phdr->p_paddr = start;
570 phdr->p_memsz = end - start;
571 phdr->p_flags = PF_R | PF_W | PF_X;
572 phdr->p_align = PAGE_SIZE;
578 * Initialize notes (new kernel)
580 static void *notes_init(Elf64_Phdr *phdr, void *ptr, u64 notes_offset)
582 struct save_area *sa;
583 void *ptr_start = ptr;
586 ptr = nt_prpsinfo(ptr);
589 list_for_each_entry(sa, &dump_save_areas, list)
591 ptr = fill_cpu_elf_notes(ptr, cpu++, sa);
592 ptr = nt_vmcoreinfo(ptr);
594 memset(phdr, 0, sizeof(*phdr));
595 phdr->p_type = PT_NOTE;
596 phdr->p_offset = notes_offset;
597 phdr->p_filesz = (unsigned long) PTR_SUB(ptr, ptr_start);
598 phdr->p_memsz = phdr->p_filesz;
602 static size_t get_elfcorehdr_size(int mem_chunk_cnt)
606 size = sizeof(Elf64_Ehdr);
608 size += sizeof(Elf64_Phdr);
610 size += nt_size(NT_PRPSINFO, sizeof(struct elf_prpsinfo));
612 size += get_cpu_cnt() * get_cpu_elf_notes_size();
614 size += nt_vmcoreinfo_size();
616 size += sizeof(Elf64_Nhdr);
618 size += mem_chunk_cnt * sizeof(Elf64_Phdr);
624 * Create ELF core header (new kernel)
626 int elfcorehdr_alloc(unsigned long long *addr, unsigned long long *size)
628 Elf64_Phdr *phdr_notes, *phdr_loads;
634 /* If we are not in kdump or zfcpdump mode return */
635 if (!OLDMEM_BASE && ipl_info.type != IPL_TYPE_FCP_DUMP)
637 /* If we cannot get HSA size for zfcpdump return error */
638 if (ipl_info.type == IPL_TYPE_FCP_DUMP && !sclp.hsa_size)
641 /* For kdump, exclude previous crashkernel memory */
643 oldmem_region.base = OLDMEM_BASE;
644 oldmem_region.size = OLDMEM_SIZE;
645 oldmem_type.total_size = OLDMEM_SIZE;
648 mem_chunk_cnt = get_mem_chunk_cnt();
650 alloc_size = get_elfcorehdr_size(mem_chunk_cnt);
652 hdr = kzalloc(alloc_size, GFP_KERNEL);
654 /* Without elfcorehdr /proc/vmcore cannot be created. Thus creating
655 * a dump with this crash kernel will fail. Panic now to allow other
656 * dump mechanisms to take over.
659 panic("s390 kdump allocating elfcorehdr failed");
661 /* Init elf header */
662 ptr = ehdr_init(hdr, mem_chunk_cnt);
663 /* Init program headers */
665 ptr = PTR_ADD(ptr, sizeof(Elf64_Phdr));
667 ptr = PTR_ADD(ptr, sizeof(Elf64_Phdr) * mem_chunk_cnt);
669 hdr_off = PTR_DIFF(ptr, hdr);
670 ptr = notes_init(phdr_notes, ptr, ((unsigned long) hdr) + hdr_off);
672 hdr_off = PTR_DIFF(ptr, hdr);
673 loads_init(phdr_loads, hdr_off);
674 *addr = (unsigned long long) hdr;
675 *size = (unsigned long long) hdr_off;
676 BUG_ON(elfcorehdr_size > alloc_size);
681 * Free ELF core header (new kernel)
683 void elfcorehdr_free(unsigned long long addr)
685 kfree((void *)(unsigned long)addr);
689 * Read from ELF header
691 ssize_t elfcorehdr_read(char *buf, size_t count, u64 *ppos)
693 void *src = (void *)(unsigned long)*ppos;
695 memcpy(buf, src, count);
701 * Read from ELF notes data
703 ssize_t elfcorehdr_read_notes(char *buf, size_t count, u64 *ppos)
705 void *src = (void *)(unsigned long)*ppos;
707 memcpy(buf, src, count);