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