1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Interface for exporting the OPAL ELF core.
4  * Heavily inspired from fs/proc/vmcore.c
5  *
6  * Copyright 2019, Hari Bathini, IBM Corporation.
7  */
8 
9 #define pr_fmt(fmt) "opal core: " fmt
10 
11 #include <linux/memblock.h>
12 #include <linux/uaccess.h>
13 #include <linux/proc_fs.h>
14 #include <linux/elf.h>
15 #include <linux/elfcore.h>
16 #include <linux/kobject.h>
17 #include <linux/sysfs.h>
18 #include <linux/slab.h>
19 #include <linux/crash_core.h>
20 #include <linux/of.h>
21 
22 #include <asm/page.h>
23 #include <asm/opal.h>
24 #include <asm/fadump-internal.h>
25 
26 #include "opal-fadump.h"
27 
28 #define MAX_PT_LOAD_CNT		8
29 
30 /* NT_AUXV note related info */
31 #define AUXV_CNT		1
32 #define AUXV_DESC_SZ		(((2 * AUXV_CNT) + 1) * sizeof(Elf64_Off))
33 
34 struct opalcore_config {
35 	u32			num_cpus;
36 	/* PIR value of crashing CPU */
37 	u32			crashing_cpu;
38 
39 	/* CPU state data info from F/W */
40 	u64			cpu_state_destination_vaddr;
41 	u64			cpu_state_data_size;
42 	u64			cpu_state_entry_size;
43 
44 	/* OPAL memory to be exported as PT_LOAD segments */
45 	u64			ptload_addr[MAX_PT_LOAD_CNT];
46 	u64			ptload_size[MAX_PT_LOAD_CNT];
47 	u64			ptload_cnt;
48 
49 	/* Pointer to the first PT_LOAD in the ELF core file */
50 	Elf64_Phdr		*ptload_phdr;
51 
52 	/* Total size of opalcore file. */
53 	size_t			opalcore_size;
54 
55 	/* Buffer for all the ELF core headers and the PT_NOTE */
56 	size_t			opalcorebuf_sz;
57 	char			*opalcorebuf;
58 
59 	/* NT_AUXV buffer */
60 	char			auxv_buf[AUXV_DESC_SZ];
61 };
62 
63 struct opalcore {
64 	struct list_head	list;
65 	u64			paddr;
66 	size_t			size;
67 	loff_t			offset;
68 };
69 
70 static LIST_HEAD(opalcore_list);
71 static struct opalcore_config *oc_conf;
72 static const struct opal_mpipl_fadump *opalc_metadata;
73 static const struct opal_mpipl_fadump *opalc_cpu_metadata;
74 static struct kobject *mpipl_kobj;
75 
76 /*
77  * Set crashing CPU's signal to SIGUSR1. if the kernel is triggered
78  * by kernel, SIGTERM otherwise.
79  */
80 bool kernel_initiated;
81 
82 static struct opalcore * __init get_new_element(void)
83 {
84 	return kzalloc(sizeof(struct opalcore), GFP_KERNEL);
85 }
86 
87 static inline int is_opalcore_usable(void)
88 {
89 	return (oc_conf && oc_conf->opalcorebuf != NULL) ? 1 : 0;
90 }
91 
92 static Elf64_Word *__init append_elf64_note(Elf64_Word *buf, char *name,
93 				     u32 type, void *data,
94 				     size_t data_len)
95 {
96 	Elf64_Nhdr *note = (Elf64_Nhdr *)buf;
97 	Elf64_Word namesz = strlen(name) + 1;
98 
99 	note->n_namesz = cpu_to_be32(namesz);
100 	note->n_descsz = cpu_to_be32(data_len);
101 	note->n_type   = cpu_to_be32(type);
102 	buf += DIV_ROUND_UP(sizeof(*note), sizeof(Elf64_Word));
103 	memcpy(buf, name, namesz);
104 	buf += DIV_ROUND_UP(namesz, sizeof(Elf64_Word));
105 	memcpy(buf, data, data_len);
106 	buf += DIV_ROUND_UP(data_len, sizeof(Elf64_Word));
107 
108 	return buf;
109 }
110 
111 static void __init fill_prstatus(struct elf_prstatus *prstatus, int pir,
112 			  struct pt_regs *regs)
113 {
114 	memset(prstatus, 0, sizeof(struct elf_prstatus));
115 	elf_core_copy_kernel_regs(&(prstatus->pr_reg), regs);
116 
117 	/*
118 	 * Overload PID with PIR value.
119 	 * As a PIR value could also be '0', add an offset of '100'
120 	 * to every PIR to avoid misinterpretations in GDB.
121 	 */
122 	prstatus->common.pr_pid  = cpu_to_be32(100 + pir);
123 	prstatus->common.pr_ppid = cpu_to_be32(1);
124 
125 	/*
126 	 * Indicate SIGUSR1 for crash initiated from kernel.
127 	 * SIGTERM otherwise.
128 	 */
129 	if (pir == oc_conf->crashing_cpu) {
130 		short sig;
131 
132 		sig = kernel_initiated ? SIGUSR1 : SIGTERM;
133 		prstatus->common.pr_cursig = cpu_to_be16(sig);
134 	}
135 }
136 
137 static Elf64_Word *__init auxv_to_elf64_notes(Elf64_Word *buf,
138 				       u64 opal_boot_entry)
139 {
140 	Elf64_Off *bufp = (Elf64_Off *)oc_conf->auxv_buf;
141 	int idx = 0;
142 
143 	memset(bufp, 0, AUXV_DESC_SZ);
144 
145 	/* Entry point of OPAL */
146 	bufp[idx++] = cpu_to_be64(AT_ENTRY);
147 	bufp[idx++] = cpu_to_be64(opal_boot_entry);
148 
149 	/* end of vector */
150 	bufp[idx++] = cpu_to_be64(AT_NULL);
151 
152 	buf = append_elf64_note(buf, CRASH_CORE_NOTE_NAME, NT_AUXV,
153 				oc_conf->auxv_buf, AUXV_DESC_SZ);
154 	return buf;
155 }
156 
157 /*
158  * Read from the ELF header and then the crash dump.
159  * Returns number of bytes read on success, -errno on failure.
160  */
161 static ssize_t read_opalcore(struct file *file, struct kobject *kobj,
162 			     struct bin_attribute *bin_attr, char *to,
163 			     loff_t pos, size_t count)
164 {
165 	struct opalcore *m;
166 	ssize_t tsz, avail;
167 	loff_t tpos = pos;
168 
169 	if (pos >= oc_conf->opalcore_size)
170 		return 0;
171 
172 	/* Adjust count if it goes beyond opalcore size */
173 	avail = oc_conf->opalcore_size - pos;
174 	if (count > avail)
175 		count = avail;
176 
177 	if (count == 0)
178 		return 0;
179 
180 	/* Read ELF core header and/or PT_NOTE segment */
181 	if (tpos < oc_conf->opalcorebuf_sz) {
182 		tsz = min_t(size_t, oc_conf->opalcorebuf_sz - tpos, count);
183 		memcpy(to, oc_conf->opalcorebuf + tpos, tsz);
184 		to += tsz;
185 		tpos += tsz;
186 		count -= tsz;
187 	}
188 
189 	list_for_each_entry(m, &opalcore_list, list) {
190 		/* nothing more to read here */
191 		if (count == 0)
192 			break;
193 
194 		if (tpos < m->offset + m->size) {
195 			void *addr;
196 
197 			tsz = min_t(size_t, m->offset + m->size - tpos, count);
198 			addr = (void *)(m->paddr + tpos - m->offset);
199 			memcpy(to, __va(addr), tsz);
200 			to += tsz;
201 			tpos += tsz;
202 			count -= tsz;
203 		}
204 	}
205 
206 	return (tpos - pos);
207 }
208 
209 static struct bin_attribute opal_core_attr = {
210 	.attr = {.name = "core", .mode = 0400},
211 	.read = read_opalcore
212 };
213 
214 /*
215  * Read CPU state dump data and convert it into ELF notes.
216  *
217  * Each register entry is of 16 bytes, A numerical identifier along with
218  * a GPR/SPR flag in the first 8 bytes and the register value in the next
219  * 8 bytes. For more details refer to F/W documentation.
220  */
221 static Elf64_Word * __init opalcore_append_cpu_notes(Elf64_Word *buf)
222 {
223 	u32 thread_pir, size_per_thread, regs_offset, regs_cnt, reg_esize;
224 	struct hdat_fadump_thread_hdr *thdr;
225 	struct elf_prstatus prstatus;
226 	Elf64_Word *first_cpu_note;
227 	struct pt_regs regs;
228 	char *bufp;
229 	int i;
230 
231 	size_per_thread = oc_conf->cpu_state_entry_size;
232 	bufp = __va(oc_conf->cpu_state_destination_vaddr);
233 
234 	/*
235 	 * Offset for register entries, entry size and registers count is
236 	 * duplicated in every thread header in keeping with HDAT format.
237 	 * Use these values from the first thread header.
238 	 */
239 	thdr = (struct hdat_fadump_thread_hdr *)bufp;
240 	regs_offset = (offsetof(struct hdat_fadump_thread_hdr, offset) +
241 		       be32_to_cpu(thdr->offset));
242 	reg_esize = be32_to_cpu(thdr->esize);
243 	regs_cnt  = be32_to_cpu(thdr->ecnt);
244 
245 	pr_debug("--------CPU State Data------------\n");
246 	pr_debug("NumCpus     : %u\n", oc_conf->num_cpus);
247 	pr_debug("\tOffset: %u, Entry size: %u, Cnt: %u\n",
248 		 regs_offset, reg_esize, regs_cnt);
249 
250 	/*
251 	 * Skip past the first CPU note. Fill this note with the
252 	 * crashing CPU's prstatus.
253 	 */
254 	first_cpu_note = buf;
255 	buf = append_elf64_note(buf, CRASH_CORE_NOTE_NAME, NT_PRSTATUS,
256 				&prstatus, sizeof(prstatus));
257 
258 	for (i = 0; i < oc_conf->num_cpus; i++, bufp += size_per_thread) {
259 		thdr = (struct hdat_fadump_thread_hdr *)bufp;
260 		thread_pir = be32_to_cpu(thdr->pir);
261 
262 		pr_debug("[%04d] PIR: 0x%x, core state: 0x%02x\n",
263 			 i, thread_pir, thdr->core_state);
264 
265 		/*
266 		 * Register state data of MAX cores is provided by firmware,
267 		 * but some of this cores may not be active. So, while
268 		 * processing register state data, check core state and
269 		 * skip threads that belong to inactive cores.
270 		 */
271 		if (thdr->core_state == HDAT_FADUMP_CORE_INACTIVE)
272 			continue;
273 
274 		opal_fadump_read_regs((bufp + regs_offset), regs_cnt,
275 				      reg_esize, false, &regs);
276 
277 		pr_debug("PIR 0x%x - R1 : 0x%llx, NIP : 0x%llx\n", thread_pir,
278 			 be64_to_cpu(regs.gpr[1]), be64_to_cpu(regs.nip));
279 		fill_prstatus(&prstatus, thread_pir, &regs);
280 
281 		if (thread_pir != oc_conf->crashing_cpu) {
282 			buf = append_elf64_note(buf, CRASH_CORE_NOTE_NAME,
283 						NT_PRSTATUS, &prstatus,
284 						sizeof(prstatus));
285 		} else {
286 			/*
287 			 * Add crashing CPU as the first NT_PRSTATUS note for
288 			 * GDB to process the core file appropriately.
289 			 */
290 			append_elf64_note(first_cpu_note, CRASH_CORE_NOTE_NAME,
291 					  NT_PRSTATUS, &prstatus,
292 					  sizeof(prstatus));
293 		}
294 	}
295 
296 	return buf;
297 }
298 
299 static int __init create_opalcore(void)
300 {
301 	u64 opal_boot_entry, opal_base_addr, paddr;
302 	u32 hdr_size, cpu_notes_size, count;
303 	struct device_node *dn;
304 	struct opalcore *new;
305 	loff_t opalcore_off;
306 	struct page *page;
307 	Elf64_Phdr *phdr;
308 	Elf64_Ehdr *elf;
309 	int i, ret;
310 	char *bufp;
311 
312 	/* Get size of header & CPU notes for OPAL core */
313 	hdr_size = (sizeof(Elf64_Ehdr) +
314 		    ((oc_conf->ptload_cnt + 1) * sizeof(Elf64_Phdr)));
315 	cpu_notes_size = ((oc_conf->num_cpus * (CRASH_CORE_NOTE_HEAD_BYTES +
316 			  CRASH_CORE_NOTE_NAME_BYTES +
317 			  CRASH_CORE_NOTE_DESC_BYTES)) +
318 			  (CRASH_CORE_NOTE_HEAD_BYTES +
319 			  CRASH_CORE_NOTE_NAME_BYTES + AUXV_DESC_SZ));
320 
321 	/* Allocate buffer to setup OPAL core */
322 	oc_conf->opalcorebuf_sz = PAGE_ALIGN(hdr_size + cpu_notes_size);
323 	oc_conf->opalcorebuf = alloc_pages_exact(oc_conf->opalcorebuf_sz,
324 						 GFP_KERNEL | __GFP_ZERO);
325 	if (!oc_conf->opalcorebuf) {
326 		pr_err("Not enough memory to setup OPAL core (size: %lu)\n",
327 		       oc_conf->opalcorebuf_sz);
328 		oc_conf->opalcorebuf_sz = 0;
329 		return -ENOMEM;
330 	}
331 	count = oc_conf->opalcorebuf_sz / PAGE_SIZE;
332 	page = virt_to_page(oc_conf->opalcorebuf);
333 	for (i = 0; i < count; i++)
334 		mark_page_reserved(page + i);
335 
336 	pr_debug("opalcorebuf = 0x%llx\n", (u64)oc_conf->opalcorebuf);
337 
338 	/* Read OPAL related device-tree entries */
339 	dn = of_find_node_by_name(NULL, "ibm,opal");
340 	if (dn) {
341 		ret = of_property_read_u64(dn, "opal-base-address",
342 					   &opal_base_addr);
343 		pr_debug("opal-base-address: %llx\n", opal_base_addr);
344 		ret |= of_property_read_u64(dn, "opal-boot-address",
345 					    &opal_boot_entry);
346 		pr_debug("opal-boot-address: %llx\n", opal_boot_entry);
347 	}
348 	if (!dn || ret)
349 		pr_warn("WARNING: Failed to read OPAL base & entry values\n");
350 
351 	/* Use count to keep track of the program headers */
352 	count = 0;
353 
354 	bufp = oc_conf->opalcorebuf;
355 	elf = (Elf64_Ehdr *)bufp;
356 	bufp += sizeof(Elf64_Ehdr);
357 	memcpy(elf->e_ident, ELFMAG, SELFMAG);
358 	elf->e_ident[EI_CLASS] = ELF_CLASS;
359 	elf->e_ident[EI_DATA] = ELFDATA2MSB;
360 	elf->e_ident[EI_VERSION] = EV_CURRENT;
361 	elf->e_ident[EI_OSABI] = ELF_OSABI;
362 	memset(elf->e_ident+EI_PAD, 0, EI_NIDENT-EI_PAD);
363 	elf->e_type = cpu_to_be16(ET_CORE);
364 	elf->e_machine = cpu_to_be16(ELF_ARCH);
365 	elf->e_version = cpu_to_be32(EV_CURRENT);
366 	elf->e_entry = 0;
367 	elf->e_phoff = cpu_to_be64(sizeof(Elf64_Ehdr));
368 	elf->e_shoff = 0;
369 	elf->e_flags = 0;
370 
371 	elf->e_ehsize = cpu_to_be16(sizeof(Elf64_Ehdr));
372 	elf->e_phentsize = cpu_to_be16(sizeof(Elf64_Phdr));
373 	elf->e_phnum = 0;
374 	elf->e_shentsize = 0;
375 	elf->e_shnum = 0;
376 	elf->e_shstrndx = 0;
377 
378 	phdr = (Elf64_Phdr *)bufp;
379 	bufp += sizeof(Elf64_Phdr);
380 	phdr->p_type	= cpu_to_be32(PT_NOTE);
381 	phdr->p_flags	= 0;
382 	phdr->p_align	= 0;
383 	phdr->p_paddr	= phdr->p_vaddr = 0;
384 	phdr->p_offset	= cpu_to_be64(hdr_size);
385 	phdr->p_filesz	= phdr->p_memsz = cpu_to_be64(cpu_notes_size);
386 	count++;
387 
388 	opalcore_off = oc_conf->opalcorebuf_sz;
389 	oc_conf->ptload_phdr  = (Elf64_Phdr *)bufp;
390 	paddr = 0;
391 	for (i = 0; i < oc_conf->ptload_cnt; i++) {
392 		phdr = (Elf64_Phdr *)bufp;
393 		bufp += sizeof(Elf64_Phdr);
394 		phdr->p_type	= cpu_to_be32(PT_LOAD);
395 		phdr->p_flags	= cpu_to_be32(PF_R|PF_W|PF_X);
396 		phdr->p_align	= 0;
397 
398 		new = get_new_element();
399 		if (!new)
400 			return -ENOMEM;
401 		new->paddr  = oc_conf->ptload_addr[i];
402 		new->size   = oc_conf->ptload_size[i];
403 		new->offset = opalcore_off;
404 		list_add_tail(&new->list, &opalcore_list);
405 
406 		phdr->p_paddr	= cpu_to_be64(paddr);
407 		phdr->p_vaddr	= cpu_to_be64(opal_base_addr + paddr);
408 		phdr->p_filesz	= phdr->p_memsz  =
409 			cpu_to_be64(oc_conf->ptload_size[i]);
410 		phdr->p_offset	= cpu_to_be64(opalcore_off);
411 
412 		count++;
413 		opalcore_off += oc_conf->ptload_size[i];
414 		paddr += oc_conf->ptload_size[i];
415 	}
416 
417 	elf->e_phnum = cpu_to_be16(count);
418 
419 	bufp = (char *)opalcore_append_cpu_notes((Elf64_Word *)bufp);
420 	bufp = (char *)auxv_to_elf64_notes((Elf64_Word *)bufp, opal_boot_entry);
421 
422 	oc_conf->opalcore_size = opalcore_off;
423 	return 0;
424 }
425 
426 static void opalcore_cleanup(void)
427 {
428 	if (oc_conf == NULL)
429 		return;
430 
431 	/* Remove OPAL core sysfs file */
432 	sysfs_remove_bin_file(mpipl_kobj, &opal_core_attr);
433 	oc_conf->ptload_phdr = NULL;
434 	oc_conf->ptload_cnt = 0;
435 
436 	/* free the buffer used for setting up OPAL core */
437 	if (oc_conf->opalcorebuf) {
438 		void *end = (void *)((u64)oc_conf->opalcorebuf +
439 				     oc_conf->opalcorebuf_sz);
440 
441 		free_reserved_area(oc_conf->opalcorebuf, end, -1, NULL);
442 		oc_conf->opalcorebuf = NULL;
443 		oc_conf->opalcorebuf_sz = 0;
444 	}
445 
446 	kfree(oc_conf);
447 	oc_conf = NULL;
448 }
449 __exitcall(opalcore_cleanup);
450 
451 static void __init opalcore_config_init(void)
452 {
453 	u32 idx, cpu_data_version;
454 	struct device_node *np;
455 	const __be32 *prop;
456 	u64 addr = 0;
457 	int i, ret;
458 
459 	np = of_find_node_by_path("/ibm,opal/dump");
460 	if (np == NULL)
461 		return;
462 
463 	if (!of_device_is_compatible(np, "ibm,opal-dump")) {
464 		pr_warn("Support missing for this f/w version!\n");
465 		return;
466 	}
467 
468 	/* Check if dump has been initiated on last reboot */
469 	prop = of_get_property(np, "mpipl-boot", NULL);
470 	if (!prop) {
471 		of_node_put(np);
472 		return;
473 	}
474 
475 	/* Get OPAL metadata */
476 	ret = opal_mpipl_query_tag(OPAL_MPIPL_TAG_OPAL, &addr);
477 	if ((ret != OPAL_SUCCESS) || !addr) {
478 		pr_err("Failed to get OPAL metadata (%d)\n", ret);
479 		goto error_out;
480 	}
481 
482 	addr = be64_to_cpu(addr);
483 	pr_debug("OPAL metadata addr: %llx\n", addr);
484 	opalc_metadata = __va(addr);
485 
486 	/* Get OPAL CPU metadata */
487 	ret = opal_mpipl_query_tag(OPAL_MPIPL_TAG_CPU, &addr);
488 	if ((ret != OPAL_SUCCESS) || !addr) {
489 		pr_err("Failed to get OPAL CPU metadata (%d)\n", ret);
490 		goto error_out;
491 	}
492 
493 	addr = be64_to_cpu(addr);
494 	pr_debug("CPU metadata addr: %llx\n", addr);
495 	opalc_cpu_metadata = __va(addr);
496 
497 	/* Allocate memory for config buffer */
498 	oc_conf = kzalloc(sizeof(struct opalcore_config), GFP_KERNEL);
499 	if (oc_conf == NULL)
500 		goto error_out;
501 
502 	/* Parse OPAL metadata */
503 	if (opalc_metadata->version != OPAL_MPIPL_VERSION) {
504 		pr_warn("Supported OPAL metadata version: %u, found: %u!\n",
505 			OPAL_MPIPL_VERSION, opalc_metadata->version);
506 		pr_warn("WARNING: F/W using newer OPAL metadata format!!\n");
507 	}
508 
509 	oc_conf->ptload_cnt = 0;
510 	idx = be32_to_cpu(opalc_metadata->region_cnt);
511 	if (idx > MAX_PT_LOAD_CNT) {
512 		pr_warn("WARNING: OPAL regions count (%d) adjusted to limit (%d)",
513 			idx, MAX_PT_LOAD_CNT);
514 		idx = MAX_PT_LOAD_CNT;
515 	}
516 	for (i = 0; i < idx; i++) {
517 		oc_conf->ptload_addr[oc_conf->ptload_cnt] =
518 				be64_to_cpu(opalc_metadata->region[i].dest);
519 		oc_conf->ptload_size[oc_conf->ptload_cnt++] =
520 				be64_to_cpu(opalc_metadata->region[i].size);
521 	}
522 	oc_conf->ptload_cnt = i;
523 	oc_conf->crashing_cpu = be32_to_cpu(opalc_metadata->crashing_pir);
524 
525 	if (!oc_conf->ptload_cnt) {
526 		pr_err("OPAL memory regions not found\n");
527 		goto error_out;
528 	}
529 
530 	/* Parse OPAL CPU metadata */
531 	cpu_data_version = be32_to_cpu(opalc_cpu_metadata->cpu_data_version);
532 	if (cpu_data_version != HDAT_FADUMP_CPU_DATA_VER) {
533 		pr_warn("Supported CPU data version: %u, found: %u!\n",
534 			HDAT_FADUMP_CPU_DATA_VER, cpu_data_version);
535 		pr_warn("WARNING: F/W using newer CPU state data format!!\n");
536 	}
537 
538 	addr = be64_to_cpu(opalc_cpu_metadata->region[0].dest);
539 	if (!addr) {
540 		pr_err("CPU state data not found!\n");
541 		goto error_out;
542 	}
543 	oc_conf->cpu_state_destination_vaddr = (u64)__va(addr);
544 
545 	oc_conf->cpu_state_data_size =
546 			be64_to_cpu(opalc_cpu_metadata->region[0].size);
547 	oc_conf->cpu_state_entry_size =
548 			be32_to_cpu(opalc_cpu_metadata->cpu_data_size);
549 
550 	if ((oc_conf->cpu_state_entry_size == 0) ||
551 	    (oc_conf->cpu_state_entry_size > oc_conf->cpu_state_data_size)) {
552 		pr_err("CPU state data is invalid.\n");
553 		goto error_out;
554 	}
555 	oc_conf->num_cpus = (oc_conf->cpu_state_data_size /
556 			     oc_conf->cpu_state_entry_size);
557 
558 	of_node_put(np);
559 	return;
560 
561 error_out:
562 	pr_err("Could not export /sys/firmware/opal/core\n");
563 	opalcore_cleanup();
564 	of_node_put(np);
565 }
566 
567 static ssize_t release_core_store(struct kobject *kobj,
568 				  struct kobj_attribute *attr,
569 				  const char *buf, size_t count)
570 {
571 	int input = -1;
572 
573 	if (kstrtoint(buf, 0, &input))
574 		return -EINVAL;
575 
576 	if (input == 1) {
577 		if (oc_conf == NULL) {
578 			pr_err("'/sys/firmware/opal/core' file not accessible!\n");
579 			return -EPERM;
580 		}
581 
582 		/*
583 		 * Take away '/sys/firmware/opal/core' and release all memory
584 		 * used for exporting this file.
585 		 */
586 		opalcore_cleanup();
587 	} else
588 		return -EINVAL;
589 
590 	return count;
591 }
592 
593 static struct kobj_attribute opalcore_rel_attr = __ATTR_WO(release_core);
594 
595 static struct attribute *mpipl_attr[] = {
596 	&opalcore_rel_attr.attr,
597 	NULL,
598 };
599 
600 static struct bin_attribute *mpipl_bin_attr[] = {
601 	&opal_core_attr,
602 	NULL,
603 
604 };
605 
606 static const struct attribute_group mpipl_group = {
607 	.attrs = mpipl_attr,
608 	.bin_attrs =  mpipl_bin_attr,
609 };
610 
611 static int __init opalcore_init(void)
612 {
613 	int rc = -1;
614 
615 	opalcore_config_init();
616 
617 	if (oc_conf == NULL)
618 		return rc;
619 
620 	create_opalcore();
621 
622 	/*
623 	 * If oc_conf->opalcorebuf= is set in the 2nd kernel,
624 	 * then capture the dump.
625 	 */
626 	if (!(is_opalcore_usable())) {
627 		pr_err("Failed to export /sys/firmware/opal/mpipl/core\n");
628 		opalcore_cleanup();
629 		return rc;
630 	}
631 
632 	/* Set OPAL core file size */
633 	opal_core_attr.size = oc_conf->opalcore_size;
634 
635 	mpipl_kobj = kobject_create_and_add("mpipl", opal_kobj);
636 	if (!mpipl_kobj) {
637 		pr_err("unable to create mpipl kobject\n");
638 		return -ENOMEM;
639 	}
640 
641 	/* Export OPAL core sysfs file */
642 	rc = sysfs_create_group(mpipl_kobj, &mpipl_group);
643 	if (rc) {
644 		pr_err("mpipl sysfs group creation failed (%d)", rc);
645 		opalcore_cleanup();
646 		return rc;
647 	}
648 	/* The /sys/firmware/opal/core is moved to /sys/firmware/opal/mpipl/
649 	 * directory, need to create symlink at old location to maintain
650 	 * backward compatibility.
651 	 */
652 	rc = compat_only_sysfs_link_entry_to_kobj(opal_kobj, mpipl_kobj,
653 						  "core", NULL);
654 	if (rc) {
655 		pr_err("unable to create core symlink (%d)\n", rc);
656 		return rc;
657 	}
658 
659 	return 0;
660 }
661 fs_initcall(opalcore_init);
662