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/switch_to.h>
33#include <asm/maccess.h>
34#include "sclp.h"
35
36#define TRACE(x...) debug_sprintf_event(zcore_dbf, 1, x)
37
38enum arch_id {
39 ARCH_S390 = 0,
40 ARCH_S390X = 1,
41};
42
43struct ipib_info {
44 unsigned long ipib;
45 u32 checksum;
46} __attribute__((packed));
47
48static struct debug_info *zcore_dbf;
49static int hsa_available;
50static struct dentry *zcore_dir;
51static struct dentry *zcore_reipl_file;
52static struct dentry *zcore_hsa_file;
53static struct ipl_parameter_block *zcore_ipl_block;
54static unsigned long os_info_flags;
55
56static DEFINE_MUTEX(hsa_buf_mutex);
57static char hsa_buf[PAGE_SIZE] __aligned(PAGE_SIZE);
58
59/*
60 * Copy memory from HSA to iterator (not reentrant):
61 *
62 * @iter: Iterator where memory should be copied to
63 * @src: Start address within HSA where data should be copied
64 * @count: Size of buffer, which should be copied
65 */
66size_t memcpy_hsa_iter(struct iov_iter *iter, unsigned long src, size_t count)
67{
68 size_t bytes, copied, res = 0;
69 unsigned long offset;
70
71 if (!hsa_available)
72 return 0;
73
74 mutex_lock(&hsa_buf_mutex);
75 while (count) {
76 if (sclp_sdias_copy(hsa_buf, src / PAGE_SIZE + 2, 1)) {
77 TRACE("sclp_sdias_copy() failed\n");
78 break;
79 }
80 offset = src % PAGE_SIZE;
81 bytes = min(PAGE_SIZE - offset, count);
82 copied = copy_to_iter(addr: hsa_buf + offset, bytes, i: iter);
83 count -= copied;
84 src += copied;
85 res += copied;
86 if (copied < bytes)
87 break;
88 }
89 mutex_unlock(lock: &hsa_buf_mutex);
90 return res;
91}
92
93/*
94 * Copy memory from HSA to kernel memory (not reentrant):
95 *
96 * @dest: Kernel or user buffer where memory should be copied to
97 * @src: Start address within HSA where data should be copied
98 * @count: Size of buffer, which should be copied
99 */
100static inline int memcpy_hsa_kernel(void *dst, unsigned long src, size_t count)
101{
102 struct iov_iter iter;
103 struct kvec kvec;
104
105 kvec.iov_base = dst;
106 kvec.iov_len = count;
107 iov_iter_kvec(i: &iter, ITER_DEST, kvec: &kvec, nr_segs: 1, count);
108 if (memcpy_hsa_iter(iter: &iter, src, count) < count)
109 return -EIO;
110 return 0;
111}
112
113static int __init init_cpu_info(void)
114{
115 struct save_area *sa;
116
117 /* get info for boot cpu from lowcore, stored in the HSA */
118 sa = save_area_boot_cpu();
119 if (!sa)
120 return -ENOMEM;
121 if (memcpy_hsa_kernel(dst: hsa_buf, src: __LC_FPREGS_SAVE_AREA, count: 512) < 0) {
122 TRACE("could not copy from HSA\n");
123 return -EIO;
124 }
125 save_area_add_regs(sa, hsa_buf); /* vx registers are saved in smp.c */
126 return 0;
127}
128
129/*
130 * Release the HSA
131 */
132static void release_hsa(void)
133{
134 diag308(DIAG308_REL_HSA, NULL);
135 hsa_available = 0;
136}
137
138static ssize_t zcore_reipl_write(struct file *filp, const char __user *buf,
139 size_t count, loff_t *ppos)
140{
141 if (zcore_ipl_block) {
142 diag308(DIAG308_SET, zcore_ipl_block);
143 if (os_info_flags & OS_INFO_FLAG_REIPL_CLEAR)
144 diag308(DIAG308_LOAD_CLEAR, NULL);
145 /* Use special diag308 subcode for CCW normal ipl */
146 if (zcore_ipl_block->pb0_hdr.pbt == IPL_PBT_CCW)
147 diag308(DIAG308_LOAD_NORMAL_DUMP, NULL);
148 else
149 diag308(DIAG308_LOAD_NORMAL, NULL);
150 }
151 return count;
152}
153
154static int zcore_reipl_open(struct inode *inode, struct file *filp)
155{
156 return stream_open(inode, filp);
157}
158
159static int zcore_reipl_release(struct inode *inode, struct file *filp)
160{
161 return 0;
162}
163
164static const struct file_operations zcore_reipl_fops = {
165 .owner = THIS_MODULE,
166 .write = zcore_reipl_write,
167 .open = zcore_reipl_open,
168 .release = zcore_reipl_release,
169 .llseek = no_llseek,
170};
171
172static ssize_t zcore_hsa_read(struct file *filp, char __user *buf,
173 size_t count, loff_t *ppos)
174{
175 static char str[18];
176
177 if (hsa_available)
178 snprintf(buf: str, size: sizeof(str), fmt: "%lx\n", sclp.hsa_size);
179 else
180 snprintf(buf: str, size: sizeof(str), fmt: "0\n");
181 return simple_read_from_buffer(to: buf, count, ppos, from: str, strlen(str));
182}
183
184static ssize_t zcore_hsa_write(struct file *filp, const char __user *buf,
185 size_t count, loff_t *ppos)
186{
187 char value;
188
189 if (*ppos != 0)
190 return -EPIPE;
191 if (copy_from_user(to: &value, from: buf, n: 1))
192 return -EFAULT;
193 if (value != '0')
194 return -EINVAL;
195 release_hsa();
196 return count;
197}
198
199static const struct file_operations zcore_hsa_fops = {
200 .owner = THIS_MODULE,
201 .write = zcore_hsa_write,
202 .read = zcore_hsa_read,
203 .open = nonseekable_open,
204 .llseek = no_llseek,
205};
206
207static int __init check_sdias(void)
208{
209 if (!sclp.hsa_size) {
210 TRACE("Could not determine HSA size\n");
211 return -ENODEV;
212 }
213 return 0;
214}
215
216/*
217 * Provide IPL parameter information block from either HSA or memory
218 * for future reipl
219 */
220static int __init zcore_reipl_init(void)
221{
222 struct os_info_entry *entry;
223 struct ipib_info ipib_info;
224 unsigned long os_info_addr;
225 struct os_info *os_info;
226 int rc;
227
228 rc = memcpy_hsa_kernel(dst: &ipib_info, src: __LC_DUMP_REIPL, count: sizeof(ipib_info));
229 if (rc)
230 return rc;
231 if (ipib_info.ipib == 0)
232 return 0;
233 zcore_ipl_block = (void *) __get_free_page(GFP_KERNEL);
234 if (!zcore_ipl_block)
235 return -ENOMEM;
236 if (ipib_info.ipib < sclp.hsa_size)
237 rc = memcpy_hsa_kernel(dst: zcore_ipl_block, src: ipib_info.ipib,
238 PAGE_SIZE);
239 else
240 rc = memcpy_real(zcore_ipl_block, ipib_info.ipib, PAGE_SIZE);
241 if (rc || (__force u32)csum_partial(buff: zcore_ipl_block, len: zcore_ipl_block->hdr.len, sum: 0) !=
242 ipib_info.checksum) {
243 TRACE("Checksum does not match\n");
244 free_page((unsigned long) zcore_ipl_block);
245 zcore_ipl_block = NULL;
246 }
247 /*
248 * Read the bit-flags field from os_info flags entry.
249 * Return zero even for os_info read or entry checksum errors in order
250 * to continue dump processing, considering that os_info could be
251 * corrupted on the panicked system.
252 */
253 os_info = (void *)__get_free_page(GFP_KERNEL);
254 if (!os_info)
255 return -ENOMEM;
256 rc = memcpy_hsa_kernel(dst: &os_info_addr, src: __LC_OS_INFO, count: sizeof(os_info_addr));
257 if (rc)
258 goto out;
259 if (os_info_addr < sclp.hsa_size)
260 rc = memcpy_hsa_kernel(dst: os_info, src: os_info_addr, PAGE_SIZE);
261 else
262 rc = memcpy_real(os_info, os_info_addr, PAGE_SIZE);
263 if (rc || os_info_csum(os_info) != os_info->csum)
264 goto out;
265 entry = &os_info->entry[OS_INFO_FLAGS_ENTRY];
266 if (entry->addr && entry->size) {
267 if (entry->addr < sclp.hsa_size)
268 rc = memcpy_hsa_kernel(dst: &os_info_flags, src: entry->addr, count: sizeof(os_info_flags));
269 else
270 rc = memcpy_real(&os_info_flags, entry->addr, sizeof(os_info_flags));
271 if (rc || (__force u32)csum_partial(buff: &os_info_flags, len: entry->size, sum: 0) != entry->csum)
272 os_info_flags = 0;
273 }
274out:
275 free_page((unsigned long)os_info);
276 return 0;
277}
278
279static int zcore_reboot_and_on_panic_handler(struct notifier_block *self,
280 unsigned long event,
281 void *data)
282{
283 if (hsa_available)
284 release_hsa();
285
286 return NOTIFY_OK;
287}
288
289static struct notifier_block zcore_reboot_notifier = {
290 .notifier_call = zcore_reboot_and_on_panic_handler,
291 /* we need to be notified before reipl and kdump */
292 .priority = INT_MAX,
293};
294
295static struct notifier_block zcore_on_panic_notifier = {
296 .notifier_call = zcore_reboot_and_on_panic_handler,
297 /* we need to be notified before reipl and kdump */
298 .priority = INT_MAX,
299};
300
301static int __init zcore_init(void)
302{
303 unsigned char arch;
304 int rc;
305
306 if (!is_ipl_type_dump())
307 return -ENODATA;
308 if (oldmem_data.start)
309 return -ENODATA;
310
311 zcore_dbf = debug_register("zcore", 4, 1, 4 * sizeof(long));
312 debug_register_view(zcore_dbf, &debug_sprintf_view);
313 debug_set_level(zcore_dbf, 6);
314
315 if (ipl_info.type == IPL_TYPE_FCP_DUMP) {
316 TRACE("type: fcp\n");
317 TRACE("devno: %x\n", ipl_info.data.fcp.dev_id.devno);
318 TRACE("wwpn: %llx\n", (unsigned long long) ipl_info.data.fcp.wwpn);
319 TRACE("lun: %llx\n", (unsigned long long) ipl_info.data.fcp.lun);
320 } else if (ipl_info.type == IPL_TYPE_NVME_DUMP) {
321 TRACE("type: nvme\n");
322 TRACE("fid: %x\n", ipl_info.data.nvme.fid);
323 TRACE("nsid: %x\n", ipl_info.data.nvme.nsid);
324 } else if (ipl_info.type == IPL_TYPE_ECKD_DUMP) {
325 TRACE("type: eckd\n");
326 TRACE("devno: %x\n", ipl_info.data.eckd.dev_id.devno);
327 TRACE("ssid: %x\n", ipl_info.data.eckd.dev_id.ssid);
328 }
329
330 rc = sclp_sdias_init();
331 if (rc)
332 goto fail;
333
334 rc = check_sdias();
335 if (rc)
336 goto fail;
337 hsa_available = 1;
338
339 rc = memcpy_hsa_kernel(&arch, __LC_AR_MODE_ID, 1);
340 if (rc)
341 goto fail;
342
343 if (arch == ARCH_S390) {
344 pr_alert("The 64-bit dump tool cannot be used for a "
345 "32-bit system\n");
346 rc = -EINVAL;
347 goto fail;
348 }
349
350 pr_alert("The dump process started for a 64-bit operating system\n");
351 rc = init_cpu_info();
352 if (rc)
353 goto fail;
354
355 rc = zcore_reipl_init();
356 if (rc)
357 goto fail;
358
359 zcore_dir = debugfs_create_dir(name: "zcore" , NULL);
360 zcore_reipl_file = debugfs_create_file(name: "reipl", S_IRUSR, parent: zcore_dir,
361 NULL, fops: &zcore_reipl_fops);
362 zcore_hsa_file = debugfs_create_file(name: "hsa", S_IRUSR|S_IWUSR, parent: zcore_dir,
363 NULL, fops: &zcore_hsa_fops);
364
365 register_reboot_notifier(&zcore_reboot_notifier);
366 atomic_notifier_chain_register(nh: &panic_notifier_list, nb: &zcore_on_panic_notifier);
367
368 return 0;
369fail:
370 diag308(DIAG308_REL_HSA, NULL);
371 return rc;
372}
373subsys_initcall(zcore_init);
374

source code of linux/drivers/s390/char/zcore.c