drivers/s390/char/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 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
  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_reipl_file;
  52 static struct dentry *zcore_hsa_file;
  53 static struct ipl_parameter_block *zcore_ipl_block;
  54 static unsigned long os_info_flags;
  55
  56 static DEFINE_MUTEX(hsa_buf_mutex);
  57 static 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  */
  66 size_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(hsa_buf + offset, bytes, iter);
  83                 count -= copied;
  84                 src += copied;
  85                 res += copied;
  86                 if (copied < bytes)
  87                         break;
  88         }
  89         mutex_unlock(&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  */
 100 static 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(&iter, ITER_DEST, &kvec, 1, count);
 108         if (memcpy_hsa_iter(&iter, src, count) < count)
 109                 return -EIO;
 110         return 0;
 111 }
 112
 113 static 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(hsa_buf, __LC_FPREGS_SAVE_AREA, 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  */
 132 static void release_hsa(void)
 133 {
 134         diag308(DIAG308_REL_HSA, NULL);
 135         hsa_available = 0;
 136 }
 137
 138 static 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
 154 static int zcore_reipl_open(struct inode *inode, struct file *filp)
 155 {
 156         return stream_open(inode, filp);
 157 }
 158
 159 static int zcore_reipl_release(struct inode *inode, struct file *filp)
 160 {
 161         return 0;
 162 }
 163
 164 static 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
 172 static 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(str, sizeof(str), "%lx\n", sclp.hsa_size);
 179         else
 180                 snprintf(str, sizeof(str), "0\n");
 181         return simple_read_from_buffer(buf, count, ppos, str, strlen(str));
 182 }
 183
 184 static 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(&value, buf, 1))
 192                 return -EFAULT;
 193         if (value != '0')
 194                 return -EINVAL;
 195         release_hsa();
 196         return count;
 197 }
 198
 199 static 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
 207 static 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  */
 220 static 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(&ipib_info, __LC_DUMP_REIPL, 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(zcore_ipl_block, 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(zcore_ipl_block, zcore_ipl_block->hdr.len, 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(&os_info_addr, __LC_OS_INFO, sizeof(os_info_addr));
 257         if (rc)
 258                 goto out;
 259         if (os_info_addr < sclp.hsa_size)
 260                 rc = memcpy_hsa_kernel(os_info, 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(&os_info_flags, entry->addr, 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(&os_info_flags, entry->size, 0) != entry->csum)
 272                         os_info_flags = 0;
 273         }
 274 out:
 275         free_page((unsigned long)os_info);
 276         return 0;
 277 }
 278
 279 static 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
 289 static 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
 295 static 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
 301 static 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("zcore" , NULL);
 360         zcore_reipl_file = debugfs_create_file("reipl", S_IRUSR, zcore_dir,
 361                                                 NULL, &zcore_reipl_fops);
 362         zcore_hsa_file = debugfs_create_file("hsa", S_IRUSR|S_IWUSR, zcore_dir,
 363                                              NULL, &zcore_hsa_fops);
 364
 365         register_reboot_notifier(&zcore_reboot_notifier);
 366         atomic_notifier_chain_register(&panic_notifier_list, &zcore_on_panic_notifier);
 367
 368         return 0;
 369 fail:
 370         diag308(DIAG308_REL_HSA, NULL);
 371         return rc;
 372 }
 373 subsys_initcall(zcore_init);