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 pr_fmt(fmt) "zdump: " fmt
 13
 14#include <linux/init.h>
 15#include <linux/slab.h>
 16#include <linux/debugfs.h>
 17#include <linux/panic_notifier.h>
 18#include <linux/reboot.h>
 19#include <linux/uio.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/maccess.h>
 32#include "sclp.h"
 33
 34#define TRACE(x...) debug_sprintf_event(zcore_dbf, 1, x)
 35
 36enum arch_id {
 37	ARCH_S390	= 0,
 38	ARCH_S390X	= 1,
 39};
 40
 41struct ipib_info {
 42	unsigned long	ipib;
 43	u32		checksum;
 44}  __attribute__((packed));
 45
 46static struct debug_info *zcore_dbf;
 47static int hsa_available;
 48static struct dentry *zcore_dir;
 49static struct dentry *zcore_reipl_file;
 50static struct dentry *zcore_hsa_file;
 51static struct ipl_parameter_block *zcore_ipl_block;
 52static unsigned long os_info_flags;
 53
 54static DEFINE_MUTEX(hsa_buf_mutex);
 55static char hsa_buf[PAGE_SIZE] __aligned(PAGE_SIZE);
 56
 57/*
 58 * Copy memory from HSA to iterator (not reentrant):
 59 *
 60 * @iter:  Iterator where memory should be copied to
 61 * @src:   Start address within HSA where data should be copied
 62 * @count: Size of buffer, which should be copied
 63 */
 64size_t memcpy_hsa_iter(struct iov_iter *iter, unsigned long src, size_t count)
 65{
 66	size_t bytes, copied, res = 0;
 67	unsigned long offset;
 68
 69	if (!hsa_available)
 70		return 0;
 71
 72	mutex_lock(&hsa_buf_mutex);
 73	while (count) {
 74		if (sclp_sdias_copy(hsa_buf, src / PAGE_SIZE + 2, 1)) {
 75			TRACE("sclp_sdias_copy() failed\n");
 76			break;
 77		}
 78		offset = src % PAGE_SIZE;
 79		bytes = min(PAGE_SIZE - offset, count);
 80		copied = copy_to_iter(hsa_buf + offset, bytes, iter);
 81		count -= copied;
 82		src += copied;
 83		res += copied;
 84		if (copied < bytes)
 85			break;
 86	}
 87	mutex_unlock(&hsa_buf_mutex);
 88	return res;
 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 */
 98static inline int memcpy_hsa_kernel(void *dst, unsigned long src, size_t count)
 99{
100	struct iov_iter iter;
101	struct kvec kvec;
102
103	kvec.iov_base = dst;
104	kvec.iov_len = count;
105	iov_iter_kvec(&iter, ITER_DEST, &kvec, 1, count);
106	if (memcpy_hsa_iter(&iter, src, count) < count)
107		return -EIO;
108	return 0;
109}
110
111static int __init init_cpu_info(void)
112{
113	struct save_area *sa;
114
115	/* get info for boot cpu from lowcore, stored in the HSA */
116	sa = save_area_boot_cpu();
117	if (!sa)
118		return -ENOMEM;
119	if (memcpy_hsa_kernel(hsa_buf, __LC_FPREGS_SAVE_AREA, 512) < 0) {
120		TRACE("could not copy from HSA\n");
121		return -EIO;
122	}
123	save_area_add_regs(sa, hsa_buf); /* vx registers are saved in smp.c */
124	return 0;
125}
126
127/*
128 * Release the HSA
129 */
130static void release_hsa(void)
131{
132	diag308(DIAG308_REL_HSA, NULL);
133	hsa_available = 0;
134}
135
136static ssize_t zcore_reipl_write(struct file *filp, const char __user *buf,
137				 size_t count, loff_t *ppos)
138{
139	if (zcore_ipl_block) {
140		diag308(DIAG308_SET, zcore_ipl_block);
141		if (os_info_flags & OS_INFO_FLAG_REIPL_CLEAR)
142			diag308(DIAG308_LOAD_CLEAR, NULL);
143		/* Use special diag308 subcode for CCW normal ipl */
144		if (zcore_ipl_block->pb0_hdr.pbt == IPL_PBT_CCW)
145			diag308(DIAG308_LOAD_NORMAL_DUMP, NULL);
146		else
147			diag308(DIAG308_LOAD_NORMAL, NULL);
148	}
149	return count;
150}
151
152static int zcore_reipl_open(struct inode *inode, struct file *filp)
153{
154	return stream_open(inode, filp);
155}
156
157static int zcore_reipl_release(struct inode *inode, struct file *filp)
158{
159	return 0;
160}
161
162static const struct file_operations zcore_reipl_fops = {
163	.owner		= THIS_MODULE,
164	.write		= zcore_reipl_write,
165	.open		= zcore_reipl_open,
166	.release	= zcore_reipl_release,
167};
168
169static ssize_t zcore_hsa_read(struct file *filp, char __user *buf,
170			      size_t count, loff_t *ppos)
171{
172	static char str[18];
173
174	if (hsa_available)
175		snprintf(str, sizeof(str), "%lx\n", sclp.hsa_size);
176	else
177		snprintf(str, sizeof(str), "0\n");
178	return simple_read_from_buffer(buf, count, ppos, str, strlen(str));
179}
180
181static ssize_t zcore_hsa_write(struct file *filp, const char __user *buf,
182			       size_t count, loff_t *ppos)
183{
184	char value;
185
186	if (*ppos != 0)
187		return -EPIPE;
188	if (copy_from_user(&value, buf, 1))
189		return -EFAULT;
190	if (value != '0')
191		return -EINVAL;
192	release_hsa();
193	return count;
194}
195
196static const struct file_operations zcore_hsa_fops = {
197	.owner		= THIS_MODULE,
198	.write		= zcore_hsa_write,
199	.read		= zcore_hsa_read,
200	.open		= nonseekable_open,
201};
202
203static int __init check_sdias(void)
204{
205	if (!sclp.hsa_size) {
206		TRACE("Could not determine HSA size\n");
207		return -ENODEV;
208	}
209	return 0;
210}
211
212/*
213 * Provide IPL parameter information block from either HSA or memory
214 * for future reipl
215 */
216static int __init zcore_reipl_init(void)
217{
218	struct os_info_entry *entry;
219	struct ipib_info ipib_info;
220	unsigned long os_info_addr;
221	struct os_info *os_info;
222	int rc;
223
224	rc = memcpy_hsa_kernel(&ipib_info, __LC_DUMP_REIPL, sizeof(ipib_info));
225	if (rc)
226		return rc;
227	if (ipib_info.ipib == 0)
228		return 0;
229	zcore_ipl_block = (void *) __get_free_page(GFP_KERNEL);
230	if (!zcore_ipl_block)
231		return -ENOMEM;
232	if (ipib_info.ipib < sclp.hsa_size)
233		rc = memcpy_hsa_kernel(zcore_ipl_block, ipib_info.ipib,
234				       PAGE_SIZE);
235	else
236		rc = memcpy_real(zcore_ipl_block, ipib_info.ipib, PAGE_SIZE);
237	if (rc || (__force u32)csum_partial(zcore_ipl_block, zcore_ipl_block->hdr.len, 0) !=
238	    ipib_info.checksum) {
239		TRACE("Checksum does not match\n");
240		free_page((unsigned long) zcore_ipl_block);
241		zcore_ipl_block = NULL;
242	}
243	/*
244	 * Read the bit-flags field from os_info flags entry.
245	 * Return zero even for os_info read or entry checksum errors in order
246	 * to continue dump processing, considering that os_info could be
247	 * corrupted on the panicked system.
248	 */
249	os_info = (void *)__get_free_page(GFP_KERNEL);
250	if (!os_info)
251		return -ENOMEM;
252	rc = memcpy_hsa_kernel(&os_info_addr, __LC_OS_INFO, sizeof(os_info_addr));
253	if (rc)
254		goto out;
255	if (os_info_addr < sclp.hsa_size)
256		rc = memcpy_hsa_kernel(os_info, os_info_addr, PAGE_SIZE);
257	else
258		rc = memcpy_real(os_info, os_info_addr, PAGE_SIZE);
259	if (rc || os_info_csum(os_info) != os_info->csum)
260		goto out;
261	entry = &os_info->entry[OS_INFO_FLAGS_ENTRY];
262	if (entry->addr && entry->size) {
263		if (entry->addr < sclp.hsa_size)
264			rc = memcpy_hsa_kernel(&os_info_flags, entry->addr, sizeof(os_info_flags));
265		else
266			rc = memcpy_real(&os_info_flags, entry->addr, sizeof(os_info_flags));
267		if (rc || (__force u32)csum_partial(&os_info_flags, entry->size, 0) != entry->csum)
268			os_info_flags = 0;
269	}
270out:
271	free_page((unsigned long)os_info);
272	return 0;
273}
274
275static int zcore_reboot_and_on_panic_handler(struct notifier_block *self,
276					     unsigned long	   event,
277					     void		   *data)
278{
279	if (hsa_available)
280		release_hsa();
281
282	return NOTIFY_OK;
283}
284
285static struct notifier_block zcore_reboot_notifier = {
286	.notifier_call	= zcore_reboot_and_on_panic_handler,
287	/* we need to be notified before reipl and kdump */
288	.priority	= INT_MAX,
289};
290
291static struct notifier_block zcore_on_panic_notifier = {
292	.notifier_call	= zcore_reboot_and_on_panic_handler,
293	/* we need to be notified before reipl and kdump */
294	.priority	= INT_MAX,
295};
296
297static int __init zcore_init(void)
298{
299	unsigned char arch;
300	int rc;
301
302	if (!is_ipl_type_dump())
303		return -ENODATA;
304	if (oldmem_data.start)
305		return -ENODATA;
306
307	zcore_dbf = debug_register("zcore", 4, 1, 4 * sizeof(long));
308	debug_register_view(zcore_dbf, &debug_sprintf_view);
309	debug_set_level(zcore_dbf, 6);
310
311	if (ipl_info.type == IPL_TYPE_FCP_DUMP) {
312		TRACE("type:   fcp\n");
313		TRACE("devno:  %x\n", ipl_info.data.fcp.dev_id.devno);
314		TRACE("wwpn:   %llx\n", (unsigned long long) ipl_info.data.fcp.wwpn);
315		TRACE("lun:    %llx\n", (unsigned long long) ipl_info.data.fcp.lun);
316	} else if (ipl_info.type == IPL_TYPE_NVME_DUMP) {
317		TRACE("type:   nvme\n");
318		TRACE("fid:    %x\n", ipl_info.data.nvme.fid);
319		TRACE("nsid:   %x\n", ipl_info.data.nvme.nsid);
320	} else if (ipl_info.type == IPL_TYPE_ECKD_DUMP) {
321		TRACE("type:   eckd\n");
322		TRACE("devno:  %x\n", ipl_info.data.eckd.dev_id.devno);
323		TRACE("ssid:   %x\n", ipl_info.data.eckd.dev_id.ssid);
324	}
325
326	rc = sclp_sdias_init();
327	if (rc)
328		goto fail;
329
330	rc = check_sdias();
331	if (rc)
332		goto fail;
333	hsa_available = 1;
334
335	rc = memcpy_hsa_kernel(&arch, __LC_AR_MODE_ID, 1);
336	if (rc)
337		goto fail;
338
339	if (arch == ARCH_S390) {
340		pr_alert("The 64-bit dump tool cannot be used for a "
341			 "32-bit system\n");
342		rc = -EINVAL;
343		goto fail;
344	}
345
346	pr_alert("The dump process started for a 64-bit operating system\n");
347	rc = init_cpu_info();
348	if (rc)
349		goto fail;
350
351	rc = zcore_reipl_init();
352	if (rc)
353		goto fail;
354
355	zcore_dir = debugfs_create_dir("zcore" , NULL);
356	zcore_reipl_file = debugfs_create_file("reipl", S_IRUSR, zcore_dir,
357						NULL, &zcore_reipl_fops);
358	zcore_hsa_file = debugfs_create_file("hsa", S_IRUSR|S_IWUSR, zcore_dir,
359					     NULL, &zcore_hsa_fops);
360
361	register_reboot_notifier(&zcore_reboot_notifier);
362	atomic_notifier_chain_register(&panic_notifier_list, &zcore_on_panic_notifier);
363
364	return 0;
365fail:
366	diag308(DIAG308_REL_HSA, NULL);
367	return rc;
368}
369subsys_initcall(zcore_init);