1// SPDX-License-Identifier: GPL-1.0+
2/*
3 * zcore module to export memory content and register sets for creating system
4 * dumps on SCSI/NVMe disks (zfcp/nvme dump).
5 *
6 * For more information please refer to Documentation/arch/s390/zfcpdump.rst
7 *
8 * Copyright IBM Corp. 2003, 2008
9 * Author(s): Michael Holzheu
10 */
11
12#define KMSG_COMPONENT "zdump"
13#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
14
15#include <linux/init.h>
16#include <linux/slab.h>
17#include <linux/debugfs.h>
18#include <linux/panic_notifier.h>
19#include <linux/reboot.h>
20#include <linux/uio.h>
21
22#include <asm/asm-offsets.h>
23#include <asm/ipl.h>
24#include <asm/sclp.h>
25#include <asm/setup.h>
26#include <linux/uaccess.h>
27#include <asm/debug.h>
28#include <asm/processor.h>
29#include <asm/irqflags.h>
30#include <asm/checksum.h>
31#include <asm/os_info.h>
32#include <asm/maccess.h>
33#include "sclp.h"
34
35#define TRACE(x...) debug_sprintf_event(zcore_dbf, 1, x)
36
37enum arch_id {
38	ARCH_S390	= 0,
39	ARCH_S390X	= 1,
40};
41
42struct ipib_info {
43	unsigned long	ipib;
44	u32		checksum;
45}  __attribute__((packed));
46
47static struct debug_info *zcore_dbf;
48static int hsa_available;
49static struct dentry *zcore_dir;
50static struct dentry *zcore_reipl_file;
51static struct dentry *zcore_hsa_file;
52static struct ipl_parameter_block *zcore_ipl_block;
53static unsigned long os_info_flags;
54
55static DEFINE_MUTEX(hsa_buf_mutex);
56static char hsa_buf[PAGE_SIZE] __aligned(PAGE_SIZE);
57
58/*
59 * Copy memory from HSA to iterator (not reentrant):
60 *
61 * @iter:  Iterator where memory should be copied to
62 * @src:   Start address within HSA where data should be copied
63 * @count: Size of buffer, which should be copied
64 */
65size_t memcpy_hsa_iter(struct iov_iter *iter, unsigned long src, size_t count)
66{
67	size_t bytes, copied, res = 0;
68	unsigned long offset;
69
70	if (!hsa_available)
71		return 0;
72
73	mutex_lock(&hsa_buf_mutex);
74	while (count) {
75		if (sclp_sdias_copy(hsa_buf, src / PAGE_SIZE + 2, 1)) {
76			TRACE("sclp_sdias_copy() failed\n");
77			break;
78		}
79		offset = src % PAGE_SIZE;
80		bytes = min(PAGE_SIZE - offset, count);
81		copied = copy_to_iter(hsa_buf + offset, bytes, iter);
82		count -= copied;
83		src += copied;
84		res += copied;
85		if (copied < bytes)
86			break;
87	}
88	mutex_unlock(&hsa_buf_mutex);
89	return res;
90}
91
92/*
93 * Copy memory from HSA to kernel memory (not reentrant):
94 *
95 * @dest:  Kernel or user buffer where memory should be copied to
96 * @src:   Start address within HSA where data should be copied
97 * @count: Size of buffer, which should be copied
98 */
99static inline int memcpy_hsa_kernel(void *dst, unsigned long src, size_t count)
100{
101	struct iov_iter iter;
102	struct kvec kvec;
103
104	kvec.iov_base = dst;
105	kvec.iov_len = count;
106	iov_iter_kvec(&iter, ITER_DEST, &kvec, 1, count);
107	if (memcpy_hsa_iter(&iter, src, count) < count)
108		return -EIO;
109	return 0;
110}
111
112static int __init init_cpu_info(void)
113{
114	struct save_area *sa;
115
116	/* get info for boot cpu from lowcore, stored in the HSA */
117	sa = save_area_boot_cpu();
118	if (!sa)
119		return -ENOMEM;
120	if (memcpy_hsa_kernel(hsa_buf, __LC_FPREGS_SAVE_AREA, 512) < 0) {
121		TRACE("could not copy from HSA\n");
122		return -EIO;
123	}
124	save_area_add_regs(sa, hsa_buf); /* vx registers are saved in smp.c */
125	return 0;
126}
127
128/*
129 * Release the HSA
130 */
131static void release_hsa(void)
132{
133	diag308(DIAG308_REL_HSA, NULL);
134	hsa_available = 0;
135}
136
137static ssize_t zcore_reipl_write(struct file *filp, const char __user *buf,
138				 size_t count, loff_t *ppos)
139{
140	if (zcore_ipl_block) {
141		diag308(DIAG308_SET, zcore_ipl_block);
142		if (os_info_flags & OS_INFO_FLAG_REIPL_CLEAR)
143			diag308(DIAG308_LOAD_CLEAR, NULL);
144		/* Use special diag308 subcode for CCW normal ipl */
145		if (zcore_ipl_block->pb0_hdr.pbt == IPL_PBT_CCW)
146			diag308(DIAG308_LOAD_NORMAL_DUMP, NULL);
147		else
148			diag308(DIAG308_LOAD_NORMAL, NULL);
149	}
150	return count;
151}
152
153static int zcore_reipl_open(struct inode *inode, struct file *filp)
154{
155	return stream_open(inode, filp);
156}
157
158static int zcore_reipl_release(struct inode *inode, struct file *filp)
159{
160	return 0;
161}
162
163static const struct file_operations zcore_reipl_fops = {
164	.owner		= THIS_MODULE,
165	.write		= zcore_reipl_write,
166	.open		= zcore_reipl_open,
167	.release	= zcore_reipl_release,
168	.llseek		= no_llseek,
169};
170
171static ssize_t zcore_hsa_read(struct file *filp, char __user *buf,
172			      size_t count, loff_t *ppos)
173{
174	static char str[18];
175
176	if (hsa_available)
177		snprintf(str, sizeof(str), "%lx\n", sclp.hsa_size);
178	else
179		snprintf(str, sizeof(str), "0\n");
180	return simple_read_from_buffer(buf, count, ppos, str, strlen(str));
181}
182
183static ssize_t zcore_hsa_write(struct file *filp, const char __user *buf,
184			       size_t count, loff_t *ppos)
185{
186	char value;
187
188	if (*ppos != 0)
189		return -EPIPE;
190	if (copy_from_user(&value, buf, 1))
191		return -EFAULT;
192	if (value != '0')
193		return -EINVAL;
194	release_hsa();
195	return count;
196}
197
198static const struct file_operations zcore_hsa_fops = {
199	.owner		= THIS_MODULE,
200	.write		= zcore_hsa_write,
201	.read		= zcore_hsa_read,
202	.open		= nonseekable_open,
203	.llseek		= no_llseek,
204};
205
206static int __init check_sdias(void)
207{
208	if (!sclp.hsa_size) {
209		TRACE("Could not determine HSA size\n");
210		return -ENODEV;
211	}
212	return 0;
213}
214
215/*
216 * Provide IPL parameter information block from either HSA or memory
217 * for future reipl
218 */
219static int __init zcore_reipl_init(void)
220{
221	struct os_info_entry *entry;
222	struct ipib_info ipib_info;
223	unsigned long os_info_addr;
224	struct os_info *os_info;
225	int rc;
226
227	rc = memcpy_hsa_kernel(&ipib_info, __LC_DUMP_REIPL, sizeof(ipib_info));
228	if (rc)
229		return rc;
230	if (ipib_info.ipib == 0)
231		return 0;
232	zcore_ipl_block = (void *) __get_free_page(GFP_KERNEL);
233	if (!zcore_ipl_block)
234		return -ENOMEM;
235	if (ipib_info.ipib < sclp.hsa_size)
236		rc = memcpy_hsa_kernel(zcore_ipl_block, ipib_info.ipib,
237				       PAGE_SIZE);
238	else
239		rc = memcpy_real(zcore_ipl_block, ipib_info.ipib, PAGE_SIZE);
240	if (rc || (__force u32)csum_partial(zcore_ipl_block, zcore_ipl_block->hdr.len, 0) !=
241	    ipib_info.checksum) {
242		TRACE("Checksum does not match\n");
243		free_page((unsigned long) zcore_ipl_block);
244		zcore_ipl_block = NULL;
245	}
246	/*
247	 * Read the bit-flags field from os_info flags entry.
248	 * Return zero even for os_info read or entry checksum errors in order
249	 * to continue dump processing, considering that os_info could be
250	 * corrupted on the panicked system.
251	 */
252	os_info = (void *)__get_free_page(GFP_KERNEL);
253	if (!os_info)
254		return -ENOMEM;
255	rc = memcpy_hsa_kernel(&os_info_addr, __LC_OS_INFO, sizeof(os_info_addr));
256	if (rc)
257		goto out;
258	if (os_info_addr < sclp.hsa_size)
259		rc = memcpy_hsa_kernel(os_info, os_info_addr, PAGE_SIZE);
260	else
261		rc = memcpy_real(os_info, os_info_addr, PAGE_SIZE);
262	if (rc || os_info_csum(os_info) != os_info->csum)
263		goto out;
264	entry = &os_info->entry[OS_INFO_FLAGS_ENTRY];
265	if (entry->addr && entry->size) {
266		if (entry->addr < sclp.hsa_size)
267			rc = memcpy_hsa_kernel(&os_info_flags, entry->addr, sizeof(os_info_flags));
268		else
269			rc = memcpy_real(&os_info_flags, entry->addr, sizeof(os_info_flags));
270		if (rc || (__force u32)csum_partial(&os_info_flags, entry->size, 0) != entry->csum)
271			os_info_flags = 0;
272	}
273out:
274	free_page((unsigned long)os_info);
275	return 0;
276}
277
278static int zcore_reboot_and_on_panic_handler(struct notifier_block *self,
279					     unsigned long	   event,
280					     void		   *data)
281{
282	if (hsa_available)
283		release_hsa();
284
285	return NOTIFY_OK;
286}
287
288static struct notifier_block zcore_reboot_notifier = {
289	.notifier_call	= zcore_reboot_and_on_panic_handler,
290	/* we need to be notified before reipl and kdump */
291	.priority	= INT_MAX,
292};
293
294static struct notifier_block zcore_on_panic_notifier = {
295	.notifier_call	= zcore_reboot_and_on_panic_handler,
296	/* we need to be notified before reipl and kdump */
297	.priority	= INT_MAX,
298};
299
300static int __init zcore_init(void)
301{
302	unsigned char arch;
303	int rc;
304
305	if (!is_ipl_type_dump())
306		return -ENODATA;
307	if (oldmem_data.start)
308		return -ENODATA;
309
310	zcore_dbf = debug_register("zcore", 4, 1, 4 * sizeof(long));
311	debug_register_view(zcore_dbf, &debug_sprintf_view);
312	debug_set_level(zcore_dbf, 6);
313
314	if (ipl_info.type == IPL_TYPE_FCP_DUMP) {
315		TRACE("type:   fcp\n");
316		TRACE("devno:  %x\n", ipl_info.data.fcp.dev_id.devno);
317		TRACE("wwpn:   %llx\n", (unsigned long long) ipl_info.data.fcp.wwpn);
318		TRACE("lun:    %llx\n", (unsigned long long) ipl_info.data.fcp.lun);
319	} else if (ipl_info.type == IPL_TYPE_NVME_DUMP) {
320		TRACE("type:   nvme\n");
321		TRACE("fid:    %x\n", ipl_info.data.nvme.fid);
322		TRACE("nsid:   %x\n", ipl_info.data.nvme.nsid);
323	} else if (ipl_info.type == IPL_TYPE_ECKD_DUMP) {
324		TRACE("type:   eckd\n");
325		TRACE("devno:  %x\n", ipl_info.data.eckd.dev_id.devno);
326		TRACE("ssid:   %x\n", ipl_info.data.eckd.dev_id.ssid);
327	}
328
329	rc = sclp_sdias_init();
330	if (rc)
331		goto fail;
332
333	rc = check_sdias();
334	if (rc)
335		goto fail;
336	hsa_available = 1;
337
338	rc = memcpy_hsa_kernel(&arch, __LC_AR_MODE_ID, 1);
339	if (rc)
340		goto fail;
341
342	if (arch == ARCH_S390) {
343		pr_alert("The 64-bit dump tool cannot be used for a "
344			 "32-bit system\n");
345		rc = -EINVAL;
346		goto fail;
347	}
348
349	pr_alert("The dump process started for a 64-bit operating system\n");
350	rc = init_cpu_info();
351	if (rc)
352		goto fail;
353
354	rc = zcore_reipl_init();
355	if (rc)
356		goto fail;
357
358	zcore_dir = debugfs_create_dir("zcore" , NULL);
359	zcore_reipl_file = debugfs_create_file("reipl", S_IRUSR, zcore_dir,
360						NULL, &zcore_reipl_fops);
361	zcore_hsa_file = debugfs_create_file("hsa", S_IRUSR|S_IWUSR, zcore_dir,
362					     NULL, &zcore_hsa_fops);
363
364	register_reboot_notifier(&zcore_reboot_notifier);
365	atomic_notifier_chain_register(&panic_notifier_list, &zcore_on_panic_notifier);
366
367	return 0;
368fail:
369	diag308(DIAG308_REL_HSA, NULL);
370	return rc;
371}
372subsys_initcall(zcore_init);
373