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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/ipl.h>
17#include <asm/os_info.h>
18
19#define PTR_ADD(x, y) (((char *) (x)) + ((unsigned long) (y)))
20#define PTR_SUB(x, y) (((char *) (x)) - ((unsigned long) (y)))
21#define PTR_DIFF(x, y) ((unsigned long)(((char *) (x)) - ((unsigned long) (y))))
22
23/*
24 * Copy one page from "oldmem"
25 *
26 * For the kdump reserved memory this functions performs a swap operation:
27 * - [OLDMEM_BASE - OLDMEM_BASE + OLDMEM_SIZE] is mapped to [0 - OLDMEM_SIZE].
28 * - [0 - OLDMEM_SIZE] is mapped to [OLDMEM_BASE - OLDMEM_BASE + OLDMEM_SIZE]
29 */
30ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
31 size_t csize, unsigned long offset, int userbuf)
32{
33 unsigned long src;
34
35 if (!csize)
36 return 0;
37
38 src = (pfn << PAGE_SHIFT) + offset;
39 if (src < OLDMEM_SIZE)
40 src += OLDMEM_BASE;
41 else if (src > OLDMEM_BASE &&
42 src < OLDMEM_BASE + OLDMEM_SIZE)
43 src -= OLDMEM_BASE;
44 if (userbuf)
45 copy_to_user_real((void __force __user *) buf, (void *) src,
46 csize);
47 else
48 memcpy_real(buf, (void *) src, csize);
49 return csize;
50}
51
52/*
53 * Copy memory from old kernel
54 */
55int copy_from_oldmem(void *dest, void *src, size_t count)
56{
57 unsigned long copied = 0;
58 int rc;
59
60 if ((unsigned long) src < OLDMEM_SIZE) {
61 copied = min(count, OLDMEM_SIZE - (unsigned long) src);
62 rc = memcpy_real(dest, src + OLDMEM_BASE, copied);
63 if (rc)
64 return rc;
65 }
66 return memcpy_real(dest + copied, src + copied, count - copied);
67}
68
69/*
70 * Alloc memory and panic in case of ENOMEM
71 */
72static void *kzalloc_panic(int len)
73{
74 void *rc;
75
76 rc = kzalloc(len, GFP_KERNEL);
77 if (!rc)
78 panic("s390 kdump kzalloc (%d) failed", len);
79 return rc;
80}
81
82/*
83 * Get memory layout and create hole for oldmem
84 */
85static struct mem_chunk *get_memory_layout(void)
86{
87 struct mem_chunk *chunk_array;
88
89 chunk_array = kzalloc_panic(MEMORY_CHUNKS * sizeof(struct mem_chunk));
90 detect_memory_layout(chunk_array);
91 create_mem_hole(chunk_array, OLDMEM_BASE, OLDMEM_SIZE, CHUNK_CRASHK);
92 return chunk_array;
93}
94
95/*
96 * Initialize ELF note
97 */
98static void *nt_init(void *buf, Elf64_Word type, void *desc, int d_len,
99 const char *name)
100{
101 Elf64_Nhdr *note;
102 u64 len;
103
104 note = (Elf64_Nhdr *)buf;
105 note->n_namesz = strlen(name) + 1;
106 note->n_descsz = d_len;
107 note->n_type = type;
108 len = sizeof(Elf64_Nhdr);
109
110 memcpy(buf + len, name, note->n_namesz);
111 len = roundup(len + note->n_namesz, 4);
112
113 memcpy(buf + len, desc, note->n_descsz);
114 len = roundup(len + note->n_descsz, 4);
115
116 return PTR_ADD(buf, len);
117}
118
119/*
120 * Initialize prstatus note
121 */
122static void *nt_prstatus(void *ptr, struct save_area *sa)
123{
124 struct elf_prstatus nt_prstatus;
125 static int cpu_nr = 1;
126
127 memset(&nt_prstatus, 0, sizeof(nt_prstatus));
128 memcpy(&nt_prstatus.pr_reg.gprs, sa->gp_regs, sizeof(sa->gp_regs));
129 memcpy(&nt_prstatus.pr_reg.psw, sa->psw, sizeof(sa->psw));
130 memcpy(&nt_prstatus.pr_reg.acrs, sa->acc_regs, sizeof(sa->acc_regs));
131 nt_prstatus.pr_pid = cpu_nr;
132 cpu_nr++;
133
134 return nt_init(ptr, NT_PRSTATUS, &nt_prstatus, sizeof(nt_prstatus),
135 "CORE");
136}
137
138/*
139 * Initialize fpregset (floating point) note
140 */
141static void *nt_fpregset(void *ptr, struct save_area *sa)
142{
143 elf_fpregset_t nt_fpregset;
144
145 memset(&nt_fpregset, 0, sizeof(nt_fpregset));
146 memcpy(&nt_fpregset.fpc, &sa->fp_ctrl_reg, sizeof(sa->fp_ctrl_reg));
147 memcpy(&nt_fpregset.fprs, &sa->fp_regs, sizeof(sa->fp_regs));
148
149 return nt_init(ptr, NT_PRFPREG, &nt_fpregset, sizeof(nt_fpregset),
150 "CORE");
151}
152
153/*
154 * Initialize timer note
155 */
156static void *nt_s390_timer(void *ptr, struct save_area *sa)
157{
158 return nt_init(ptr, NT_S390_TIMER, &sa->timer, sizeof(sa->timer),
159 KEXEC_CORE_NOTE_NAME);
160}
161
162/*
163 * Initialize TOD clock comparator note
164 */
165static void *nt_s390_tod_cmp(void *ptr, struct save_area *sa)
166{
167 return nt_init(ptr, NT_S390_TODCMP, &sa->clk_cmp,
168 sizeof(sa->clk_cmp), KEXEC_CORE_NOTE_NAME);
169}
170
171/*
172 * Initialize TOD programmable register note
173 */
174static void *nt_s390_tod_preg(void *ptr, struct save_area *sa)
175{
176 return nt_init(ptr, NT_S390_TODPREG, &sa->tod_reg,
177 sizeof(sa->tod_reg), KEXEC_CORE_NOTE_NAME);
178}
179
180/*
181 * Initialize control register note
182 */
183static void *nt_s390_ctrs(void *ptr, struct save_area *sa)
184{
185 return nt_init(ptr, NT_S390_CTRS, &sa->ctrl_regs,
186 sizeof(sa->ctrl_regs), KEXEC_CORE_NOTE_NAME);
187}
188
189/*
190 * Initialize prefix register note
191 */
192static void *nt_s390_prefix(void *ptr, struct save_area *sa)
193{
194 return nt_init(ptr, NT_S390_PREFIX, &sa->pref_reg,
195 sizeof(sa->pref_reg), KEXEC_CORE_NOTE_NAME);
196}
197
198/*
199 * Fill ELF notes for one CPU with save area registers
200 */
201void *fill_cpu_elf_notes(void *ptr, struct save_area *sa)
202{
203 ptr = nt_prstatus(ptr, sa);
204 ptr = nt_fpregset(ptr, sa);
205 ptr = nt_s390_timer(ptr, sa);
206 ptr = nt_s390_tod_cmp(ptr, sa);
207 ptr = nt_s390_tod_preg(ptr, sa);
208 ptr = nt_s390_ctrs(ptr, sa);
209 ptr = nt_s390_prefix(ptr, sa);
210 return ptr;
211}
212
213/*
214 * Initialize prpsinfo note (new kernel)
215 */
216static void *nt_prpsinfo(void *ptr)
217{
218 struct elf_prpsinfo prpsinfo;
219
220 memset(&prpsinfo, 0, sizeof(prpsinfo));
221 prpsinfo.pr_sname = 'R';
222 strcpy(prpsinfo.pr_fname, "vmlinux");
223 return nt_init(ptr, NT_PRPSINFO, &prpsinfo, sizeof(prpsinfo),
224 KEXEC_CORE_NOTE_NAME);
225}
226
227/*
228 * Get vmcoreinfo using lowcore->vmcore_info (new kernel)
229 */
230static void *get_vmcoreinfo_old(unsigned long *size)
231{
232 char nt_name[11], *vmcoreinfo;
233 Elf64_Nhdr note;
234 void *addr;
235
236 if (copy_from_oldmem(&addr, &S390_lowcore.vmcore_info, sizeof(addr)))
237 return NULL;
238 memset(nt_name, 0, sizeof(nt_name));
239 if (copy_from_oldmem(¬e, addr, sizeof(note)))
240 return NULL;
241 if (copy_from_oldmem(nt_name, addr + sizeof(note), sizeof(nt_name) - 1))
242 return NULL;
243 if (strcmp(nt_name, "VMCOREINFO") != 0)
244 return NULL;
245 vmcoreinfo = kzalloc_panic(note.n_descsz);
246 if (copy_from_oldmem(vmcoreinfo, addr + 24, note.n_descsz))
247 return NULL;
248 *size = note.n_descsz;
249 return vmcoreinfo;
250}
251
252/*
253 * Initialize vmcoreinfo note (new kernel)
254 */
255static void *nt_vmcoreinfo(void *ptr)
256{
257 unsigned long size;
258 void *vmcoreinfo;
259
260 vmcoreinfo = os_info_old_entry(OS_INFO_VMCOREINFO, &size);
261 if (!vmcoreinfo)
262 vmcoreinfo = get_vmcoreinfo_old(&size);
263 if (!vmcoreinfo)
264 return ptr;
265 return nt_init(ptr, 0, vmcoreinfo, size, "VMCOREINFO");
266}
267
268/*
269 * Initialize ELF header (new kernel)
270 */
271static void *ehdr_init(Elf64_Ehdr *ehdr, int mem_chunk_cnt)
272{
273 memset(ehdr, 0, sizeof(*ehdr));
274 memcpy(ehdr->e_ident, ELFMAG, SELFMAG);
275 ehdr->e_ident[EI_CLASS] = ELFCLASS64;
276 ehdr->e_ident[EI_DATA] = ELFDATA2MSB;
277 ehdr->e_ident[EI_VERSION] = EV_CURRENT;
278 memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD);
279 ehdr->e_type = ET_CORE;
280 ehdr->e_machine = EM_S390;
281 ehdr->e_version = EV_CURRENT;
282 ehdr->e_phoff = sizeof(Elf64_Ehdr);
283 ehdr->e_ehsize = sizeof(Elf64_Ehdr);
284 ehdr->e_phentsize = sizeof(Elf64_Phdr);
285 ehdr->e_phnum = mem_chunk_cnt + 1;
286 return ehdr + 1;
287}
288
289/*
290 * Return CPU count for ELF header (new kernel)
291 */
292static int get_cpu_cnt(void)
293{
294 int i, cpus = 0;
295
296 for (i = 0; zfcpdump_save_areas[i]; i++) {
297 if (zfcpdump_save_areas[i]->pref_reg == 0)
298 continue;
299 cpus++;
300 }
301 return cpus;
302}
303
304/*
305 * Return memory chunk count for ELF header (new kernel)
306 */
307static int get_mem_chunk_cnt(void)
308{
309 struct mem_chunk *chunk_array, *mem_chunk;
310 int i, cnt = 0;
311
312 chunk_array = get_memory_layout();
313 for (i = 0; i < MEMORY_CHUNKS; i++) {
314 mem_chunk = &chunk_array[i];
315 if (chunk_array[i].type != CHUNK_READ_WRITE &&
316 chunk_array[i].type != CHUNK_READ_ONLY)
317 continue;
318 if (mem_chunk->size == 0)
319 continue;
320 cnt++;
321 }
322 kfree(chunk_array);
323 return cnt;
324}
325
326/*
327 * Relocate pointer in order to allow vmcore code access the data
328 */
329static inline unsigned long relocate(unsigned long addr)
330{
331 return OLDMEM_BASE + addr;
332}
333
334/*
335 * Initialize ELF loads (new kernel)
336 */
337static int loads_init(Elf64_Phdr *phdr, u64 loads_offset)
338{
339 struct mem_chunk *chunk_array, *mem_chunk;
340 int i;
341
342 chunk_array = get_memory_layout();
343 for (i = 0; i < MEMORY_CHUNKS; i++) {
344 mem_chunk = &chunk_array[i];
345 if (mem_chunk->size == 0)
346 break;
347 if (chunk_array[i].type != CHUNK_READ_WRITE &&
348 chunk_array[i].type != CHUNK_READ_ONLY)
349 continue;
350 else
351 phdr->p_filesz = mem_chunk->size;
352 phdr->p_type = PT_LOAD;
353 phdr->p_offset = mem_chunk->addr;
354 phdr->p_vaddr = mem_chunk->addr;
355 phdr->p_paddr = mem_chunk->addr;
356 phdr->p_memsz = mem_chunk->size;
357 phdr->p_flags = PF_R | PF_W | PF_X;
358 phdr->p_align = PAGE_SIZE;
359 phdr++;
360 }
361 kfree(chunk_array);
362 return i;
363}
364
365/*
366 * Initialize notes (new kernel)
367 */
368static void *notes_init(Elf64_Phdr *phdr, void *ptr, u64 notes_offset)
369{
370 struct save_area *sa;
371 void *ptr_start = ptr;
372 int i;
373
374 ptr = nt_prpsinfo(ptr);
375
376 for (i = 0; zfcpdump_save_areas[i]; i++) {
377 sa = zfcpdump_save_areas[i];
378 if (sa->pref_reg == 0)
379 continue;
380 ptr = fill_cpu_elf_notes(ptr, sa);
381 }
382 ptr = nt_vmcoreinfo(ptr);
383 memset(phdr, 0, sizeof(*phdr));
384 phdr->p_type = PT_NOTE;
385 phdr->p_offset = relocate(notes_offset);
386 phdr->p_filesz = (unsigned long) PTR_SUB(ptr, ptr_start);
387 phdr->p_memsz = phdr->p_filesz;
388 return ptr;
389}
390
391/*
392 * Create ELF core header (new kernel)
393 */
394static void s390_elf_corehdr_create(char **elfcorebuf, size_t *elfcorebuf_sz)
395{
396 Elf64_Phdr *phdr_notes, *phdr_loads;
397 int mem_chunk_cnt;
398 void *ptr, *hdr;
399 u32 alloc_size;
400 u64 hdr_off;
401
402 mem_chunk_cnt = get_mem_chunk_cnt();
403
404 alloc_size = 0x1000 + get_cpu_cnt() * 0x300 +
405 mem_chunk_cnt * sizeof(Elf64_Phdr);
406 hdr = kzalloc_panic(alloc_size);
407 /* Init elf header */
408 ptr = ehdr_init(hdr, mem_chunk_cnt);
409 /* Init program headers */
410 phdr_notes = ptr;
411 ptr = PTR_ADD(ptr, sizeof(Elf64_Phdr));
412 phdr_loads = ptr;
413 ptr = PTR_ADD(ptr, sizeof(Elf64_Phdr) * mem_chunk_cnt);
414 /* Init notes */
415 hdr_off = PTR_DIFF(ptr, hdr);
416 ptr = notes_init(phdr_notes, ptr, ((unsigned long) hdr) + hdr_off);
417 /* Init loads */
418 hdr_off = PTR_DIFF(ptr, hdr);
419 loads_init(phdr_loads, ((unsigned long) hdr) + hdr_off);
420 *elfcorebuf_sz = hdr_off;
421 *elfcorebuf = (void *) relocate((unsigned long) hdr);
422 BUG_ON(*elfcorebuf_sz > alloc_size);
423}
424
425/*
426 * Create kdump ELF core header in new kernel, if it has not been passed via
427 * the "elfcorehdr" kernel parameter
428 */
429static int setup_kdump_elfcorehdr(void)
430{
431 size_t elfcorebuf_sz;
432 char *elfcorebuf;
433
434 if (!OLDMEM_BASE || is_kdump_kernel())
435 return -EINVAL;
436 s390_elf_corehdr_create(&elfcorebuf, &elfcorebuf_sz);
437 elfcorehdr_addr = (unsigned long long) elfcorebuf;
438 elfcorehdr_size = elfcorebuf_sz;
439 return 0;
440}
441
442subsys_initcall(setup_kdump_elfcorehdr);