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/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/reboot.h>
  19
  20 #include <asm/asm-offsets.h>
  21 #include <asm/ipl.h>
  22 #include <asm/sclp.h>
  23 #include <asm/setup.h>
  24 #include <linux/uaccess.h>
  25 #include <asm/debug.h>
  26 #include <asm/processor.h>
  27 #include <asm/irqflags.h>
  28 #include <asm/checksum.h>
  29 #include <asm/os_info.h>
  30 #include <asm/switch_to.h>
  31 #include "sclp.h"
  32
  33 #define TRACE(x...) debug_sprintf_event(zcore_dbf, 1, x)
  34
  35 enum arch_id {
  36         ARCH_S390       = 0,
  37         ARCH_S390X      = 1,
  38 };
  39
  40 struct ipib_info {
  41         unsigned long   ipib;
  42         u32             checksum;
  43 }  __attribute__((packed));
  44
  45 static struct debug_info *zcore_dbf;
  46 static int hsa_available;
  47 static struct dentry *zcore_dir;
  48 static struct dentry *zcore_reipl_file;
  49 static struct dentry *zcore_hsa_file;
  50 static struct ipl_parameter_block *zcore_ipl_block;
  51
  52 static char hsa_buf[PAGE_SIZE] __aligned(PAGE_SIZE);
  53
  54 /*
  55  * Copy memory from HSA to user memory (not reentrant):
  56  *
  57  * @dest:  User buffer where memory should be copied to
  58  * @src:   Start address within HSA where data should be copied
  59  * @count: Size of buffer, which should be copied
  60  */
  61 int memcpy_hsa_user(void __user *dest, unsigned long src, size_t count)
  62 {
  63         unsigned long offset, bytes;
  64
  65         if (!hsa_available)
  66                 return -ENODATA;
  67
  68         while (count) {
  69                 if (sclp_sdias_copy(hsa_buf, src / PAGE_SIZE + 2, 1)) {
  70                         TRACE("sclp_sdias_copy() failed\n");
  71                         return -EIO;
  72                 }
  73                 offset = src % PAGE_SIZE;
  74                 bytes = min(PAGE_SIZE - offset, count);
  75                 if (copy_to_user(dest, hsa_buf + offset, bytes))
  76                         return -EFAULT;
  77                 src += bytes;
  78                 dest += bytes;
  79                 count -= bytes;
  80         }
  81         return 0;
  82 }
  83
  84 /*
  85  * Copy memory from HSA to kernel memory (not reentrant):
  86  *
  87  * @dest:  Kernel or user buffer where memory should be copied to
  88  * @src:   Start address within HSA where data should be copied
  89  * @count: Size of buffer, which should be copied
  90  */
  91 int memcpy_hsa_kernel(void *dest, unsigned long src, size_t count)
  92 {
  93         unsigned long offset, bytes;
  94
  95         if (!hsa_available)
  96                 return -ENODATA;
  97
  98         while (count) {
  99                 if (sclp_sdias_copy(hsa_buf, src / PAGE_SIZE + 2, 1)) {
 100                         TRACE("sclp_sdias_copy() failed\n");
 101                         return -EIO;
 102                 }
 103                 offset = src % PAGE_SIZE;
 104                 bytes = min(PAGE_SIZE - offset, count);
 105                 memcpy(dest, hsa_buf + offset, bytes);
 106                 src += bytes;
 107                 dest += bytes;
 108                 count -= bytes;
 109         }
 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                 diag308(DIAG308_LOAD_CLEAR, NULL);
 144         }
 145         return count;
 146 }
 147
 148 static int zcore_reipl_open(struct inode *inode, struct file *filp)
 149 {
 150         return stream_open(inode, filp);
 151 }
 152
 153 static int zcore_reipl_release(struct inode *inode, struct file *filp)
 154 {
 155         return 0;
 156 }
 157
 158 static const struct file_operations zcore_reipl_fops = {
 159         .owner          = THIS_MODULE,
 160         .write          = zcore_reipl_write,
 161         .open           = zcore_reipl_open,
 162         .release        = zcore_reipl_release,
 163         .llseek         = no_llseek,
 164 };
 165
 166 static ssize_t zcore_hsa_read(struct file *filp, char __user *buf,
 167                               size_t count, loff_t *ppos)
 168 {
 169         static char str[18];
 170
 171         if (hsa_available)
 172                 snprintf(str, sizeof(str), "%lx\n", sclp.hsa_size);
 173         else
 174                 snprintf(str, sizeof(str), "0\n");
 175         return simple_read_from_buffer(buf, count, ppos, str, strlen(str));
 176 }
 177
 178 static ssize_t zcore_hsa_write(struct file *filp, const char __user *buf,
 179                                size_t count, loff_t *ppos)
 180 {
 181         char value;
 182
 183         if (*ppos != 0)
 184                 return -EPIPE;
 185         if (copy_from_user(&value, buf, 1))
 186                 return -EFAULT;
 187         if (value != '0')
 188                 return -EINVAL;
 189         release_hsa();
 190         return count;
 191 }
 192
 193 static const struct file_operations zcore_hsa_fops = {
 194         .owner          = THIS_MODULE,
 195         .write          = zcore_hsa_write,
 196         .read           = zcore_hsa_read,
 197         .open           = nonseekable_open,
 198         .llseek         = no_llseek,
 199 };
 200
 201 static int __init check_sdias(void)
 202 {
 203         if (!sclp.hsa_size) {
 204                 TRACE("Could not determine HSA size\n");
 205                 return -ENODEV;
 206         }
 207         return 0;
 208 }
 209
 210 /*
 211  * Provide IPL parameter information block from either HSA or memory
 212  * for future reipl
 213  */
 214 static int __init zcore_reipl_init(void)
 215 {
 216         struct ipib_info ipib_info;
 217         int rc;
 218
 219         rc = memcpy_hsa_kernel(&ipib_info, __LC_DUMP_REIPL, sizeof(ipib_info));
 220         if (rc)
 221                 return rc;
 222         if (ipib_info.ipib == 0)
 223                 return 0;
 224         zcore_ipl_block = (void *) __get_free_page(GFP_KERNEL);
 225         if (!zcore_ipl_block)
 226                 return -ENOMEM;
 227         if (ipib_info.ipib < sclp.hsa_size)
 228                 rc = memcpy_hsa_kernel(zcore_ipl_block, ipib_info.ipib,
 229                                        PAGE_SIZE);
 230         else
 231                 rc = memcpy_real(zcore_ipl_block, (void *) ipib_info.ipib,
 232                                  PAGE_SIZE);
 233         if (rc || (__force u32)csum_partial(zcore_ipl_block, zcore_ipl_block->hdr.len, 0) !=
 234             ipib_info.checksum) {
 235                 TRACE("Checksum does not match\n");
 236                 free_page((unsigned long) zcore_ipl_block);
 237                 zcore_ipl_block = NULL;
 238         }
 239         return 0;
 240 }
 241
 242 static int zcore_reboot_and_on_panic_handler(struct notifier_block *self,
 243                                              unsigned long         event,
 244                                              void                  *data)
 245 {
 246         if (hsa_available)
 247                 release_hsa();
 248
 249         return NOTIFY_OK;
 250 }
 251
 252 static struct notifier_block zcore_reboot_notifier = {
 253         .notifier_call  = zcore_reboot_and_on_panic_handler,
 254         /* we need to be notified before reipl and kdump */
 255         .priority       = INT_MAX,
 256 };
 257
 258 static struct notifier_block zcore_on_panic_notifier = {
 259         .notifier_call  = zcore_reboot_and_on_panic_handler,
 260         /* we need to be notified before reipl and kdump */
 261         .priority       = INT_MAX,
 262 };
 263
 264 static int __init zcore_init(void)
 265 {
 266         unsigned char arch;
 267         int rc;
 268
 269         if (!is_ipl_type_dump())
 270                 return -ENODATA;
 271         if (OLDMEM_BASE)
 272                 return -ENODATA;
 273
 274         zcore_dbf = debug_register("zcore", 4, 1, 4 * sizeof(long));
 275         debug_register_view(zcore_dbf, &debug_sprintf_view);
 276         debug_set_level(zcore_dbf, 6);
 277
 278         if (ipl_info.type == IPL_TYPE_FCP_DUMP) {
 279                 TRACE("type:   fcp\n");
 280                 TRACE("devno:  %x\n", ipl_info.data.fcp.dev_id.devno);
 281                 TRACE("wwpn:   %llx\n", (unsigned long long) ipl_info.data.fcp.wwpn);
 282                 TRACE("lun:    %llx\n", (unsigned long long) ipl_info.data.fcp.lun);
 283         } else if (ipl_info.type == IPL_TYPE_NVME_DUMP) {
 284                 TRACE("type:   nvme\n");
 285                 TRACE("fid:    %x\n", ipl_info.data.nvme.fid);
 286                 TRACE("nsid:   %x\n", ipl_info.data.nvme.nsid);
 287         }
 288
 289         rc = sclp_sdias_init();
 290         if (rc)
 291                 goto fail;
 292
 293         rc = check_sdias();
 294         if (rc)
 295                 goto fail;
 296         hsa_available = 1;
 297
 298         rc = memcpy_hsa_kernel(&arch, __LC_AR_MODE_ID, 1);
 299         if (rc)
 300                 goto fail;
 301
 302         if (arch == ARCH_S390) {
 303                 pr_alert("The 64-bit dump tool cannot be used for a "
 304                          "32-bit system\n");
 305                 rc = -EINVAL;
 306                 goto fail;
 307         }
 308
 309         pr_alert("The dump process started for a 64-bit operating system\n");
 310         rc = init_cpu_info();
 311         if (rc)
 312                 goto fail;
 313
 314         rc = zcore_reipl_init();
 315         if (rc)
 316                 goto fail;
 317
 318         zcore_dir = debugfs_create_dir("zcore" , NULL);
 319         zcore_reipl_file = debugfs_create_file("reipl", S_IRUSR, zcore_dir,
 320                                                 NULL, &zcore_reipl_fops);
 321         zcore_hsa_file = debugfs_create_file("hsa", S_IRUSR|S_IWUSR, zcore_dir,
 322                                              NULL, &zcore_hsa_fops);
 323
 324         register_reboot_notifier(&zcore_reboot_notifier);
 325         atomic_notifier_chain_register(&panic_notifier_list, &zcore_on_panic_notifier);
 326
 327         return 0;
 328 fail:
 329         diag308(DIAG308_REL_HSA, NULL);
 330         return rc;
 331 }
 332 subsys_initcall(zcore_init);