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