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[J-linux.git] / drivers / s390 / char / zcore.c
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  */
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  */
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
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  */
131 static void release_hsa(void)
132 {
133         diag308(DIAG308_REL_HSA, NULL);
134         hsa_available = 0;
135 }
136
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
153 static int zcore_reipl_open(struct inode *inode, struct file *filp)
154 {
155         return stream_open(inode, filp);
156 }
157
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 };
169
170 static ssize_t zcore_hsa_read(struct file *filp, char __user *buf,
171                               size_t count, loff_t *ppos)
172 {
173         static char str[18];
174
175         if (hsa_available)
176                 snprintf(str, sizeof(str), "%lx\n", sclp.hsa_size);
177         else
178                 snprintf(str, sizeof(str), "0\n");
179         return simple_read_from_buffer(buf, count, ppos, str, strlen(str));
180 }
181
182 static ssize_t zcore_hsa_write(struct file *filp, const char __user *buf,
183                                size_t count, loff_t *ppos)
184 {
185         char value;
186
187         if (*ppos != 0)
188                 return -EPIPE;
189         if (copy_from_user(&value, buf, 1))
190                 return -EFAULT;
191         if (value != '0')
192                 return -EINVAL;
193         release_hsa();
194         return count;
195 }
196
197 static const struct file_operations zcore_hsa_fops = {
198         .owner          = THIS_MODULE,
199         .write          = zcore_hsa_write,
200         .read           = zcore_hsa_read,
201         .open           = nonseekable_open,
202 };
203
204 static int __init check_sdias(void)
205 {
206         if (!sclp.hsa_size) {
207                 TRACE("Could not determine HSA size\n");
208                 return -ENODEV;
209         }
210         return 0;
211 }
212
213 /*
214  * Provide IPL parameter information block from either HSA or memory
215  * for future reipl
216  */
217 static int __init zcore_reipl_init(void)
218 {
219         struct os_info_entry *entry;
220         struct ipib_info ipib_info;
221         unsigned long os_info_addr;
222         struct os_info *os_info;
223         int rc;
224
225         rc = memcpy_hsa_kernel(&ipib_info, __LC_DUMP_REIPL, sizeof(ipib_info));
226         if (rc)
227                 return rc;
228         if (ipib_info.ipib == 0)
229                 return 0;
230         zcore_ipl_block = (void *) __get_free_page(GFP_KERNEL);
231         if (!zcore_ipl_block)
232                 return -ENOMEM;
233         if (ipib_info.ipib < sclp.hsa_size)
234                 rc = memcpy_hsa_kernel(zcore_ipl_block, ipib_info.ipib,
235                                        PAGE_SIZE);
236         else
237                 rc = memcpy_real(zcore_ipl_block, ipib_info.ipib, PAGE_SIZE);
238         if (rc || (__force u32)csum_partial(zcore_ipl_block, zcore_ipl_block->hdr.len, 0) !=
239             ipib_info.checksum) {
240                 TRACE("Checksum does not match\n");
241                 free_page((unsigned long) zcore_ipl_block);
242                 zcore_ipl_block = NULL;
243         }
244         /*
245          * Read the bit-flags field from os_info flags entry.
246          * Return zero even for os_info read or entry checksum errors in order
247          * to continue dump processing, considering that os_info could be
248          * corrupted on the panicked system.
249          */
250         os_info = (void *)__get_free_page(GFP_KERNEL);
251         if (!os_info)
252                 return -ENOMEM;
253         rc = memcpy_hsa_kernel(&os_info_addr, __LC_OS_INFO, sizeof(os_info_addr));
254         if (rc)
255                 goto out;
256         if (os_info_addr < sclp.hsa_size)
257                 rc = memcpy_hsa_kernel(os_info, os_info_addr, PAGE_SIZE);
258         else
259                 rc = memcpy_real(os_info, os_info_addr, PAGE_SIZE);
260         if (rc || os_info_csum(os_info) != os_info->csum)
261                 goto out;
262         entry = &os_info->entry[OS_INFO_FLAGS_ENTRY];
263         if (entry->addr && entry->size) {
264                 if (entry->addr < sclp.hsa_size)
265                         rc = memcpy_hsa_kernel(&os_info_flags, entry->addr, sizeof(os_info_flags));
266                 else
267                         rc = memcpy_real(&os_info_flags, entry->addr, sizeof(os_info_flags));
268                 if (rc || (__force u32)csum_partial(&os_info_flags, entry->size, 0) != entry->csum)
269                         os_info_flags = 0;
270         }
271 out:
272         free_page((unsigned long)os_info);
273         return 0;
274 }
275
276 static int zcore_reboot_and_on_panic_handler(struct notifier_block *self,
277                                              unsigned long         event,
278                                              void                  *data)
279 {
280         if (hsa_available)
281                 release_hsa();
282
283         return NOTIFY_OK;
284 }
285
286 static struct notifier_block zcore_reboot_notifier = {
287         .notifier_call  = zcore_reboot_and_on_panic_handler,
288         /* we need to be notified before reipl and kdump */
289         .priority       = INT_MAX,
290 };
291
292 static struct notifier_block zcore_on_panic_notifier = {
293         .notifier_call  = zcore_reboot_and_on_panic_handler,
294         /* we need to be notified before reipl and kdump */
295         .priority       = INT_MAX,
296 };
297
298 static int __init zcore_init(void)
299 {
300         unsigned char arch;
301         int rc;
302
303         if (!is_ipl_type_dump())
304                 return -ENODATA;
305         if (oldmem_data.start)
306                 return -ENODATA;
307
308         zcore_dbf = debug_register("zcore", 4, 1, 4 * sizeof(long));
309         debug_register_view(zcore_dbf, &debug_sprintf_view);
310         debug_set_level(zcore_dbf, 6);
311
312         if (ipl_info.type == IPL_TYPE_FCP_DUMP) {
313                 TRACE("type:   fcp\n");
314                 TRACE("devno:  %x\n", ipl_info.data.fcp.dev_id.devno);
315                 TRACE("wwpn:   %llx\n", (unsigned long long) ipl_info.data.fcp.wwpn);
316                 TRACE("lun:    %llx\n", (unsigned long long) ipl_info.data.fcp.lun);
317         } else if (ipl_info.type == IPL_TYPE_NVME_DUMP) {
318                 TRACE("type:   nvme\n");
319                 TRACE("fid:    %x\n", ipl_info.data.nvme.fid);
320                 TRACE("nsid:   %x\n", ipl_info.data.nvme.nsid);
321         } else if (ipl_info.type == IPL_TYPE_ECKD_DUMP) {
322                 TRACE("type:   eckd\n");
323                 TRACE("devno:  %x\n", ipl_info.data.eckd.dev_id.devno);
324                 TRACE("ssid:   %x\n", ipl_info.data.eckd.dev_id.ssid);
325         }
326
327         rc = sclp_sdias_init();
328         if (rc)
329                 goto fail;
330
331         rc = check_sdias();
332         if (rc)
333                 goto fail;
334         hsa_available = 1;
335
336         rc = memcpy_hsa_kernel(&arch, __LC_AR_MODE_ID, 1);
337         if (rc)
338                 goto fail;
339
340         if (arch == ARCH_S390) {
341                 pr_alert("The 64-bit dump tool cannot be used for a "
342                          "32-bit system\n");
343                 rc = -EINVAL;
344                 goto fail;
345         }
346
347         pr_alert("The dump process started for a 64-bit operating system\n");
348         rc = init_cpu_info();
349         if (rc)
350                 goto fail;
351
352         rc = zcore_reipl_init();
353         if (rc)
354                 goto fail;
355
356         zcore_dir = debugfs_create_dir("zcore" , NULL);
357         zcore_reipl_file = debugfs_create_file("reipl", S_IRUSR, zcore_dir,
358                                                 NULL, &zcore_reipl_fops);
359         zcore_hsa_file = debugfs_create_file("hsa", S_IRUSR|S_IWUSR, zcore_dir,
360                                              NULL, &zcore_hsa_fops);
361
362         register_reboot_notifier(&zcore_reboot_notifier);
363         atomic_notifier_chain_register(&panic_notifier_list, &zcore_on_panic_notifier);
364
365         return 0;
366 fail:
367         diag308(DIAG308_REL_HSA, NULL);
368         return rc;
369 }
370 subsys_initcall(zcore_init);
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