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
37 enum arch_id {
38 ARCH_S390 = 0,
39 ARCH_S390X = 1,
40 };
41
42 struct ipib_info {
43 unsigned long ipib;
44 u32 checksum;
45 } __attribute__((packed));
46
47 static struct debug_info *zcore_dbf;
48 static int hsa_available;
49 static struct dentry *zcore_dir;
50 static struct dentry *zcore_reipl_file;
51 static struct dentry *zcore_hsa_file;
52 static struct ipl_parameter_block *zcore_ipl_block;
53 static unsigned long os_info_flags;
54
55 static DEFINE_MUTEX(hsa_buf_mutex);
56 static 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 */
memcpy_hsa_iter(struct iov_iter * iter,unsigned long src,size_t count)65 size_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 */
memcpy_hsa_kernel(void * dst,unsigned long src,size_t count)99 static 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
init_cpu_info(void)112 static 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 */
release_hsa(void)131 static void release_hsa(void)
132 {
133 diag308(DIAG308_REL_HSA, NULL);
134 hsa_available = 0;
135 }
136
zcore_reipl_write(struct file * filp,const char __user * buf,size_t count,loff_t * ppos)137 static 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
zcore_reipl_open(struct inode * inode,struct file * filp)153 static int zcore_reipl_open(struct inode *inode, struct file *filp)
154 {
155 return stream_open(inode, filp);
156 }
157
zcore_reipl_release(struct inode * inode,struct file * filp)158 static int zcore_reipl_release(struct inode *inode, struct file *filp)
159 {
160 return 0;
161 }
162
163 static 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
zcore_hsa_read(struct file * filp,char __user * buf,size_t count,loff_t * ppos)171 static 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
zcore_hsa_write(struct file * filp,const char __user * buf,size_t count,loff_t * ppos)183 static 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
198 static 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
check_sdias(void)206 static 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 */
zcore_reipl_init(void)219 static 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 }
273 out:
274 free_page((unsigned long)os_info);
275 return 0;
276 }
277
zcore_reboot_and_on_panic_handler(struct notifier_block * self,unsigned long event,void * data)278 static 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
288 static 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
294 static 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
zcore_init(void)300 static 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;
368 fail:
369 diag308(DIAG308_REL_HSA, NULL);
370 return rc;
371 }
372 subsys_initcall(zcore_init);
373