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