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 disks (zfcpdump). The "zcore/mem" debugfs file shows the same
5 * dump format as s390 standalone dumps.
6 *
7 * For more information please refer to Documentation/s390/zfcpdump.rst
8 *
9 * Copyright IBM Corp. 2003, 2008
10 * Author(s): Michael Holzheu
11 */
12
13 #define KMSG_COMPONENT "zdump"
14 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
15
16 #include <linux/init.h>
17 #include <linux/slab.h>
18 #include <linux/debugfs.h>
19 #include <linux/memblock.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 #define CHUNK_INFO_SIZE 34 /* 2 16-byte char, each followed by blank */
37
38 enum arch_id {
39 ARCH_S390 = 0,
40 ARCH_S390X = 1,
41 };
42
43 struct ipib_info {
44 unsigned long ipib;
45 u32 checksum;
46 } __attribute__((packed));
47
48 static struct debug_info *zcore_dbf;
49 static int hsa_available;
50 static struct dentry *zcore_dir;
51 static struct dentry *zcore_memmap_file;
52 static struct dentry *zcore_reipl_file;
53 static struct dentry *zcore_hsa_file;
54 static struct ipl_parameter_block *zcore_ipl_block;
55
56 static char hsa_buf[PAGE_SIZE] __aligned(PAGE_SIZE);
57
58 /*
59 * Copy memory from HSA to user memory (not reentrant):
60 *
61 * @dest: User buffer 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_user(void __user * dest,unsigned long src,size_t count)65 int memcpy_hsa_user(void __user *dest, unsigned long src, size_t count)
66 {
67 unsigned long offset, bytes;
68
69 if (!hsa_available)
70 return -ENODATA;
71
72 while (count) {
73 if (sclp_sdias_copy(hsa_buf, src / PAGE_SIZE + 2, 1)) {
74 TRACE("sclp_sdias_copy() failed\n");
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 return -EFAULT;
81 src += bytes;
82 dest += bytes;
83 count -= bytes;
84 }
85 return 0;
86 }
87
88 /*
89 * Copy memory from HSA to kernel memory (not reentrant):
90 *
91 * @dest: Kernel or user buffer where memory should be copied to
92 * @src: Start address within HSA where data should be copied
93 * @count: Size of buffer, which should be copied
94 */
memcpy_hsa_kernel(void * dest,unsigned long src,size_t count)95 int memcpy_hsa_kernel(void *dest, unsigned long src, size_t count)
96 {
97 unsigned long offset, bytes;
98
99 if (!hsa_available)
100 return -ENODATA;
101
102 while (count) {
103 if (sclp_sdias_copy(hsa_buf, src / PAGE_SIZE + 2, 1)) {
104 TRACE("sclp_sdias_copy() failed\n");
105 return -EIO;
106 }
107 offset = src % PAGE_SIZE;
108 bytes = min(PAGE_SIZE - offset, count);
109 memcpy(dest, hsa_buf + offset, bytes);
110 src += bytes;
111 dest += bytes;
112 count -= bytes;
113 }
114 return 0;
115 }
116
init_cpu_info(void)117 static int __init init_cpu_info(void)
118 {
119 struct save_area *sa;
120
121 /* get info for boot cpu from lowcore, stored in the HSA */
122 sa = save_area_boot_cpu();
123 if (!sa)
124 return -ENOMEM;
125 if (memcpy_hsa_kernel(hsa_buf, __LC_FPREGS_SAVE_AREA, 512) < 0) {
126 TRACE("could not copy from HSA\n");
127 return -EIO;
128 }
129 save_area_add_regs(sa, hsa_buf); /* vx registers are saved in smp.c */
130 return 0;
131 }
132
133 /*
134 * Release the HSA
135 */
release_hsa(void)136 static void release_hsa(void)
137 {
138 diag308(DIAG308_REL_HSA, NULL);
139 hsa_available = 0;
140 }
141
zcore_memmap_read(struct file * filp,char __user * buf,size_t count,loff_t * ppos)142 static ssize_t zcore_memmap_read(struct file *filp, char __user *buf,
143 size_t count, loff_t *ppos)
144 {
145 return simple_read_from_buffer(buf, count, ppos, filp->private_data,
146 memblock.memory.cnt * CHUNK_INFO_SIZE);
147 }
148
zcore_memmap_open(struct inode * inode,struct file * filp)149 static int zcore_memmap_open(struct inode *inode, struct file *filp)
150 {
151 struct memblock_region *reg;
152 char *buf;
153 int i = 0;
154
155 buf = kcalloc(memblock.memory.cnt, CHUNK_INFO_SIZE, GFP_KERNEL);
156 if (!buf) {
157 return -ENOMEM;
158 }
159 for_each_memblock(memory, reg) {
160 sprintf(buf + (i++ * CHUNK_INFO_SIZE), "%016llx %016llx ",
161 (unsigned long long) reg->base,
162 (unsigned long long) reg->size);
163 }
164 filp->private_data = buf;
165 return nonseekable_open(inode, filp);
166 }
167
zcore_memmap_release(struct inode * inode,struct file * filp)168 static int zcore_memmap_release(struct inode *inode, struct file *filp)
169 {
170 kfree(filp->private_data);
171 return 0;
172 }
173
174 static const struct file_operations zcore_memmap_fops = {
175 .owner = THIS_MODULE,
176 .read = zcore_memmap_read,
177 .open = zcore_memmap_open,
178 .release = zcore_memmap_release,
179 .llseek = no_llseek,
180 };
181
zcore_reipl_write(struct file * filp,const char __user * buf,size_t count,loff_t * ppos)182 static ssize_t zcore_reipl_write(struct file *filp, const char __user *buf,
183 size_t count, loff_t *ppos)
184 {
185 if (zcore_ipl_block) {
186 diag308(DIAG308_SET, zcore_ipl_block);
187 diag308(DIAG308_LOAD_CLEAR, NULL);
188 }
189 return count;
190 }
191
zcore_reipl_open(struct inode * inode,struct file * filp)192 static int zcore_reipl_open(struct inode *inode, struct file *filp)
193 {
194 return stream_open(inode, filp);
195 }
196
zcore_reipl_release(struct inode * inode,struct file * filp)197 static int zcore_reipl_release(struct inode *inode, struct file *filp)
198 {
199 return 0;
200 }
201
202 static const struct file_operations zcore_reipl_fops = {
203 .owner = THIS_MODULE,
204 .write = zcore_reipl_write,
205 .open = zcore_reipl_open,
206 .release = zcore_reipl_release,
207 .llseek = no_llseek,
208 };
209
zcore_hsa_read(struct file * filp,char __user * buf,size_t count,loff_t * ppos)210 static ssize_t zcore_hsa_read(struct file *filp, char __user *buf,
211 size_t count, loff_t *ppos)
212 {
213 static char str[18];
214
215 if (hsa_available)
216 snprintf(str, sizeof(str), "%lx\n", sclp.hsa_size);
217 else
218 snprintf(str, sizeof(str), "0\n");
219 return simple_read_from_buffer(buf, count, ppos, str, strlen(str));
220 }
221
zcore_hsa_write(struct file * filp,const char __user * buf,size_t count,loff_t * ppos)222 static ssize_t zcore_hsa_write(struct file *filp, const char __user *buf,
223 size_t count, loff_t *ppos)
224 {
225 char value;
226
227 if (*ppos != 0)
228 return -EPIPE;
229 if (copy_from_user(&value, buf, 1))
230 return -EFAULT;
231 if (value != '0')
232 return -EINVAL;
233 release_hsa();
234 return count;
235 }
236
237 static const struct file_operations zcore_hsa_fops = {
238 .owner = THIS_MODULE,
239 .write = zcore_hsa_write,
240 .read = zcore_hsa_read,
241 .open = nonseekable_open,
242 .llseek = no_llseek,
243 };
244
check_sdias(void)245 static int __init check_sdias(void)
246 {
247 if (!sclp.hsa_size) {
248 TRACE("Could not determine HSA size\n");
249 return -ENODEV;
250 }
251 return 0;
252 }
253
254 /*
255 * Provide IPL parameter information block from either HSA or memory
256 * for future reipl
257 */
zcore_reipl_init(void)258 static int __init zcore_reipl_init(void)
259 {
260 struct ipib_info ipib_info;
261 int rc;
262
263 rc = memcpy_hsa_kernel(&ipib_info, __LC_DUMP_REIPL, sizeof(ipib_info));
264 if (rc)
265 return rc;
266 if (ipib_info.ipib == 0)
267 return 0;
268 zcore_ipl_block = (void *) __get_free_page(GFP_KERNEL);
269 if (!zcore_ipl_block)
270 return -ENOMEM;
271 if (ipib_info.ipib < sclp.hsa_size)
272 rc = memcpy_hsa_kernel(zcore_ipl_block, ipib_info.ipib,
273 PAGE_SIZE);
274 else
275 rc = memcpy_real(zcore_ipl_block, (void *) ipib_info.ipib,
276 PAGE_SIZE);
277 if (rc || (__force u32)csum_partial(zcore_ipl_block, zcore_ipl_block->hdr.len, 0) !=
278 ipib_info.checksum) {
279 TRACE("Checksum does not match\n");
280 free_page((unsigned long) zcore_ipl_block);
281 zcore_ipl_block = NULL;
282 }
283 return 0;
284 }
285
zcore_init(void)286 static int __init zcore_init(void)
287 {
288 unsigned char arch;
289 int rc;
290
291 if (ipl_info.type != IPL_TYPE_FCP_DUMP)
292 return -ENODATA;
293 if (OLDMEM_BASE)
294 return -ENODATA;
295
296 zcore_dbf = debug_register("zcore", 4, 1, 4 * sizeof(long));
297 debug_register_view(zcore_dbf, &debug_sprintf_view);
298 debug_set_level(zcore_dbf, 6);
299
300 TRACE("devno: %x\n", ipl_info.data.fcp.dev_id.devno);
301 TRACE("wwpn: %llx\n", (unsigned long long) ipl_info.data.fcp.wwpn);
302 TRACE("lun: %llx\n", (unsigned long long) ipl_info.data.fcp.lun);
303
304 rc = sclp_sdias_init();
305 if (rc)
306 goto fail;
307
308 rc = check_sdias();
309 if (rc)
310 goto fail;
311 hsa_available = 1;
312
313 rc = memcpy_hsa_kernel(&arch, __LC_AR_MODE_ID, 1);
314 if (rc)
315 goto fail;
316
317 if (arch == ARCH_S390) {
318 pr_alert("The 64-bit dump tool cannot be used for a "
319 "32-bit system\n");
320 rc = -EINVAL;
321 goto fail;
322 }
323
324 pr_alert("The dump process started for a 64-bit operating system\n");
325 rc = init_cpu_info();
326 if (rc)
327 goto fail;
328
329 rc = zcore_reipl_init();
330 if (rc)
331 goto fail;
332
333 zcore_dir = debugfs_create_dir("zcore" , NULL);
334 if (!zcore_dir) {
335 rc = -ENOMEM;
336 goto fail;
337 }
338 zcore_memmap_file = debugfs_create_file("memmap", S_IRUSR, zcore_dir,
339 NULL, &zcore_memmap_fops);
340 if (!zcore_memmap_file) {
341 rc = -ENOMEM;
342 goto fail_dir;
343 }
344 zcore_reipl_file = debugfs_create_file("reipl", S_IRUSR, zcore_dir,
345 NULL, &zcore_reipl_fops);
346 if (!zcore_reipl_file) {
347 rc = -ENOMEM;
348 goto fail_memmap_file;
349 }
350 zcore_hsa_file = debugfs_create_file("hsa", S_IRUSR|S_IWUSR, zcore_dir,
351 NULL, &zcore_hsa_fops);
352 if (!zcore_hsa_file) {
353 rc = -ENOMEM;
354 goto fail_reipl_file;
355 }
356 return 0;
357
358 fail_reipl_file:
359 debugfs_remove(zcore_reipl_file);
360 fail_memmap_file:
361 debugfs_remove(zcore_memmap_file);
362 fail_dir:
363 debugfs_remove(zcore_dir);
364 fail:
365 diag308(DIAG308_REL_HSA, NULL);
366 return rc;
367 }
368 subsys_initcall(zcore_init);
369
