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