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
  19 #include <asm/asm-offsets.h>
  20 #include <asm/ipl.h>
  21 #include <asm/sclp.h>
  22 #include <asm/setup.h>
  23 #include <linux/uaccess.h>
  24 #include <asm/debug.h>
  25 #include <asm/processor.h>
  26 #include <asm/irqflags.h>
  27 #include <asm/checksum.h>
  28 #include <asm/os_info.h>
  29 #include <asm/switch_to.h>
  30 #include "sclp.h"
  31
  32 #define TRACE(x...) debug_sprintf_event(zcore_dbf, 1, x)
  33
  34 enum arch_id {
  35         ARCH_S390       = 0,
  36         ARCH_S390X      = 1,
  37 };
  38
  39 struct ipib_info {
  40         unsigned long   ipib;
  41         u32             checksum;
  42 }  __attribute__((packed));
  43
  44 static struct debug_info *zcore_dbf;
  45 static int hsa_available;
  46 static struct dentry *zcore_dir;
  47 static struct dentry *zcore_reipl_file;
  48 static struct dentry *zcore_hsa_file;
  49 static struct ipl_parameter_block *zcore_ipl_block;
  50
  51 static DEFINE_MUTEX(hsa_buf_mutex);
  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         mutex_lock(&hsa_buf_mutex);
  69         while (count) {
  70                 if (sclp_sdias_copy(hsa_buf, src / PAGE_SIZE + 2, 1)) {
  71                         TRACE("sclp_sdias_copy() failed\n");
  72                         mutex_unlock(&hsa_buf_mutex);
  73                         return -EIO;
  74                 }
  75                 offset = src % PAGE_SIZE;
  76                 bytes = min(PAGE_SIZE - offset, count);
  77                 if (copy_to_user(dest, hsa_buf + offset, bytes)) {
  78                         mutex_unlock(&hsa_buf_mutex);
  79                         return -EFAULT;
  80                 }
  81                 src += bytes;
  82                 dest += bytes;
  83                 count -= bytes;
  84         }
  85         mutex_unlock(&hsa_buf_mutex);
  86         return 0;
  87 }
  88
  89 /*
  90  * Copy memory from HSA to kernel memory (not reentrant):
  91  *
  92  * @dest:  Kernel or user buffer where memory should be copied to
  93  * @src:   Start address within HSA where data should be copied
  94  * @count: Size of buffer, which should be copied
  95  */
  96 int memcpy_hsa_kernel(void *dest, unsigned long src, size_t count)
  97 {
  98         unsigned long offset, bytes;
  99
 100         if (!hsa_available)
 101                 return -ENODATA;
 102
 103         mutex_lock(&hsa_buf_mutex);
 104         while (count) {
 105                 if (sclp_sdias_copy(hsa_buf, src / PAGE_SIZE + 2, 1)) {
 106                         TRACE("sclp_sdias_copy() failed\n");
 107                         mutex_unlock(&hsa_buf_mutex);
 108                         return -EIO;
 109                 }
 110                 offset = src % PAGE_SIZE;
 111                 bytes = min(PAGE_SIZE - offset, count);
 112                 memcpy(dest, hsa_buf + offset, bytes);
 113                 src += bytes;
 114                 dest += bytes;
 115                 count -= bytes;
 116         }
 117         mutex_unlock(&hsa_buf_mutex);
 118         return 0;
 119 }
 120
 121 static int __init init_cpu_info(void)
 122 {
 123         struct save_area *sa;
 124
 125         /* get info for boot cpu from lowcore, stored in the HSA */
 126         sa = save_area_boot_cpu();
 127         if (!sa)
 128                 return -ENOMEM;
 129         if (memcpy_hsa_kernel(hsa_buf, __LC_FPREGS_SAVE_AREA, 512) < 0) {
 130                 TRACE("could not copy from HSA\n");
 131                 return -EIO;
 132         }
 133         save_area_add_regs(sa, hsa_buf); /* vx registers are saved in smp.c */
 134         return 0;
 135 }
 136
 137 /*
 138  * Release the HSA
 139  */
 140 static void release_hsa(void)
 141 {
 142         diag308(DIAG308_REL_HSA, NULL);
 143         hsa_available = 0;
 144 }
 145
 146 static ssize_t zcore_reipl_write(struct file *filp, const char __user *buf,
 147                                  size_t count, loff_t *ppos)
 148 {
 149         if (zcore_ipl_block) {
 150                 diag308(DIAG308_SET, zcore_ipl_block);
 151                 diag308(DIAG308_LOAD_CLEAR, NULL);
 152         }
 153         return count;
 154 }
 155
 156 static int zcore_reipl_open(struct inode *inode, struct file *filp)
 157 {
 158         return stream_open(inode, filp);
 159 }
 160
 161 static int zcore_reipl_release(struct inode *inode, struct file *filp)
 162 {
 163         return 0;
 164 }
 165
 166 static const struct file_operations zcore_reipl_fops = {
 167         .owner          = THIS_MODULE,
 168         .write          = zcore_reipl_write,
 169         .open           = zcore_reipl_open,
 170         .release        = zcore_reipl_release,
 171         .llseek         = no_llseek,
 172 };
 173
 174 static ssize_t zcore_hsa_read(struct file *filp, char __user *buf,
 175                               size_t count, loff_t *ppos)
 176 {
 177         static char str[18];
 178
 179         if (hsa_available)
 180                 snprintf(str, sizeof(str), "%lx\n", sclp.hsa_size);
 181         else
 182                 snprintf(str, sizeof(str), "0\n");
 183         return simple_read_from_buffer(buf, count, ppos, str, strlen(str));
 184 }
 185
 186 static ssize_t zcore_hsa_write(struct file *filp, const char __user *buf,
 187                                size_t count, loff_t *ppos)
 188 {
 189         char value;
 190
 191         if (*ppos != 0)
 192                 return -EPIPE;
 193         if (copy_from_user(&value, buf, 1))
 194                 return -EFAULT;
 195         if (value != '0')
 196                 return -EINVAL;
 197         release_hsa();
 198         return count;
 199 }
 200
 201 static const struct file_operations zcore_hsa_fops = {
 202         .owner          = THIS_MODULE,
 203         .write          = zcore_hsa_write,
 204         .read           = zcore_hsa_read,
 205         .open           = nonseekable_open,
 206         .llseek         = no_llseek,
 207 };
 208
 209 static int __init check_sdias(void)
 210 {
 211         if (!sclp.hsa_size) {
 212                 TRACE("Could not determine HSA size\n");
 213                 return -ENODEV;
 214         }
 215         return 0;
 216 }
 217
 218 /*
 219  * Provide IPL parameter information block from either HSA or memory
 220  * for future reipl
 221  */
 222 static int __init zcore_reipl_init(void)
 223 {
 224         struct ipib_info ipib_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, (void *) ipib_info.ipib,
 240                                  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         return 0;
 248 }
 249
 250 static int __init zcore_init(void)
 251 {
 252         unsigned char arch;
 253         int rc;
 254
 255         if (!is_ipl_type_dump())
 256                 return -ENODATA;
 257         if (OLDMEM_BASE)
 258                 return -ENODATA;
 259
 260         zcore_dbf = debug_register("zcore", 4, 1, 4 * sizeof(long));
 261         debug_register_view(zcore_dbf, &debug_sprintf_view);
 262         debug_set_level(zcore_dbf, 6);
 263
 264         if (ipl_info.type == IPL_TYPE_FCP_DUMP) {
 265                 TRACE("type:   fcp\n");
 266                 TRACE("devno:  %x\n", ipl_info.data.fcp.dev_id.devno);
 267                 TRACE("wwpn:   %llx\n", (unsigned long long) ipl_info.data.fcp.wwpn);
 268                 TRACE("lun:    %llx\n", (unsigned long long) ipl_info.data.fcp.lun);
 269         } else if (ipl_info.type == IPL_TYPE_NVME_DUMP) {
 270                 TRACE("type:   nvme\n");
 271                 TRACE("fid:    %x\n", ipl_info.data.nvme.fid);
 272                 TRACE("nsid:   %x\n", ipl_info.data.nvme.nsid);
 273         }
 274
 275         rc = sclp_sdias_init();
 276         if (rc)
 277                 goto fail;
 278
 279         rc = check_sdias();
 280         if (rc)
 281                 goto fail;
 282         hsa_available = 1;
 283
 284         rc = memcpy_hsa_kernel(&arch, __LC_AR_MODE_ID, 1);
 285         if (rc)
 286                 goto fail;
 287
 288         if (arch == ARCH_S390) {
 289                 pr_alert("The 64-bit dump tool cannot be used for a "
 290                          "32-bit system\n");
 291                 rc = -EINVAL;
 292                 goto fail;
 293         }
 294
 295         pr_alert("The dump process started for a 64-bit operating system\n");
 296         rc = init_cpu_info();
 297         if (rc)
 298                 goto fail;
 299
 300         rc = zcore_reipl_init();
 301         if (rc)
 302                 goto fail;
 303
 304         zcore_dir = debugfs_create_dir("zcore" , NULL);
 305         if (!zcore_dir) {
 306                 rc = -ENOMEM;
 307                 goto fail;
 308         }
 309         zcore_reipl_file = debugfs_create_file("reipl", S_IRUSR, zcore_dir,
 310                                                 NULL, &zcore_reipl_fops);
 311         if (!zcore_reipl_file) {
 312                 rc = -ENOMEM;
 313                 goto fail_dir;
 314         }
 315         zcore_hsa_file = debugfs_create_file("hsa", S_IRUSR|S_IWUSR, zcore_dir,
 316                                              NULL, &zcore_hsa_fops);
 317         if (!zcore_hsa_file) {
 318                 rc = -ENOMEM;
 319                 goto fail_reipl_file;
 320         }
 321         return 0;
 322
 323 fail_reipl_file:
 324         debugfs_remove(zcore_reipl_file);
 325 fail_dir:
 326         debugfs_remove(zcore_dir);
 327 fail:
 328         diag308(DIAG308_REL_HSA, NULL);
 329         return rc;
 330 }
 331 subsys_initcall(zcore_init);