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 char hsa_buf[PAGE_SIZE] __aligned(PAGE_SIZE);
  52
  53 /*
  54  * Copy memory from HSA to user memory (not reentrant):
  55  *
  56  * @dest:  User buffer where memory should be copied to
  57  * @src:   Start address within HSA where data should be copied
  58  * @count: Size of buffer, which should be copied
  59  */
  60 int memcpy_hsa_user(void __user *dest, unsigned long src, size_t count)
  61 {
  62         unsigned long offset, bytes;
  63
  64         if (!hsa_available)
  65                 return -ENODATA;
  66
  67         while (count) {
  68                 if (sclp_sdias_copy(hsa_buf, src / PAGE_SIZE + 2, 1)) {
  69                         TRACE("sclp_sdias_copy() failed\n");
  70                         return -EIO;
  71                 }
  72                 offset = src % PAGE_SIZE;
  73                 bytes = min(PAGE_SIZE - offset, count);
  74                 if (copy_to_user(dest, hsa_buf + offset, bytes))
  75                         return -EFAULT;
  76                 src += bytes;
  77                 dest += bytes;
  78                 count -= bytes;
  79         }
  80         return 0;
  81 }
  82
  83 /*
  84  * Copy memory from HSA to kernel memory (not reentrant):
  85  *
  86  * @dest:  Kernel or user buffer where memory should be copied to
  87  * @src:   Start address within HSA where data should be copied
  88  * @count: Size of buffer, which should be copied
  89  */
  90 int memcpy_hsa_kernel(void *dest, unsigned long src, size_t count)
  91 {
  92         unsigned long offset, bytes;
  93
  94         if (!hsa_available)
  95                 return -ENODATA;
  96
  97         while (count) {
  98                 if (sclp_sdias_copy(hsa_buf, src / PAGE_SIZE + 2, 1)) {
  99                         TRACE("sclp_sdias_copy() failed\n");
 100                         return -EIO;
 101                 }
 102                 offset = src % PAGE_SIZE;
 103                 bytes = min(PAGE_SIZE - offset, count);
 104                 memcpy(dest, hsa_buf + offset, bytes);
 105                 src += bytes;
 106                 dest += bytes;
 107                 count -= bytes;
 108         }
 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                 diag308(DIAG308_LOAD_CLEAR, NULL);
 143         }
 144         return count;
 145 }
 146
 147 static int zcore_reipl_open(struct inode *inode, struct file *filp)
 148 {
 149         return stream_open(inode, filp);
 150 }
 151
 152 static int zcore_reipl_release(struct inode *inode, struct file *filp)
 153 {
 154         return 0;
 155 }
 156
 157 static const struct file_operations zcore_reipl_fops = {
 158         .owner          = THIS_MODULE,
 159         .write          = zcore_reipl_write,
 160         .open           = zcore_reipl_open,
 161         .release        = zcore_reipl_release,
 162         .llseek         = no_llseek,
 163 };
 164
 165 static ssize_t zcore_hsa_read(struct file *filp, char __user *buf,
 166                               size_t count, loff_t *ppos)
 167 {
 168         static char str[18];
 169
 170         if (hsa_available)
 171                 snprintf(str, sizeof(str), "%lx\n", sclp.hsa_size);
 172         else
 173                 snprintf(str, sizeof(str), "0\n");
 174         return simple_read_from_buffer(buf, count, ppos, str, strlen(str));
 175 }
 176
 177 static ssize_t zcore_hsa_write(struct file *filp, const char __user *buf,
 178                                size_t count, loff_t *ppos)
 179 {
 180         char value;
 181
 182         if (*ppos != 0)
 183                 return -EPIPE;
 184         if (copy_from_user(&value, buf, 1))
 185                 return -EFAULT;
 186         if (value != '0')
 187                 return -EINVAL;
 188         release_hsa();
 189         return count;
 190 }
 191
 192 static const struct file_operations zcore_hsa_fops = {
 193         .owner          = THIS_MODULE,
 194         .write          = zcore_hsa_write,
 195         .read           = zcore_hsa_read,
 196         .open           = nonseekable_open,
 197         .llseek         = no_llseek,
 198 };
 199
 200 static int __init check_sdias(void)
 201 {
 202         if (!sclp.hsa_size) {
 203                 TRACE("Could not determine HSA size\n");
 204                 return -ENODEV;
 205         }
 206         return 0;
 207 }
 208
 209 /*
 210  * Provide IPL parameter information block from either HSA or memory
 211  * for future reipl
 212  */
 213 static int __init zcore_reipl_init(void)
 214 {
 215         struct ipib_info ipib_info;
 216         int rc;
 217
 218         rc = memcpy_hsa_kernel(&ipib_info, __LC_DUMP_REIPL, sizeof(ipib_info));
 219         if (rc)
 220                 return rc;
 221         if (ipib_info.ipib == 0)
 222                 return 0;
 223         zcore_ipl_block = (void *) __get_free_page(GFP_KERNEL);
 224         if (!zcore_ipl_block)
 225                 return -ENOMEM;
 226         if (ipib_info.ipib < sclp.hsa_size)
 227                 rc = memcpy_hsa_kernel(zcore_ipl_block, ipib_info.ipib,
 228                                        PAGE_SIZE);
 229         else
 230                 rc = memcpy_real(zcore_ipl_block, (void *) ipib_info.ipib,
 231                                  PAGE_SIZE);
 232         if (rc || (__force u32)csum_partial(zcore_ipl_block, zcore_ipl_block->hdr.len, 0) !=
 233             ipib_info.checksum) {
 234                 TRACE("Checksum does not match\n");
 235                 free_page((unsigned long) zcore_ipl_block);
 236                 zcore_ipl_block = NULL;
 237         }
 238         return 0;
 239 }
 240
 241 static int __init zcore_init(void)
 242 {
 243         unsigned char arch;
 244         int rc;
 245
 246         if (!is_ipl_type_dump())
 247                 return -ENODATA;
 248         if (OLDMEM_BASE)
 249                 return -ENODATA;
 250
 251         zcore_dbf = debug_register("zcore", 4, 1, 4 * sizeof(long));
 252         debug_register_view(zcore_dbf, &debug_sprintf_view);
 253         debug_set_level(zcore_dbf, 6);
 254
 255         if (ipl_info.type == IPL_TYPE_FCP_DUMP) {
 256                 TRACE("type:   fcp\n");
 257                 TRACE("devno:  %x\n", ipl_info.data.fcp.dev_id.devno);
 258                 TRACE("wwpn:   %llx\n", (unsigned long long) ipl_info.data.fcp.wwpn);
 259                 TRACE("lun:    %llx\n", (unsigned long long) ipl_info.data.fcp.lun);
 260         } else if (ipl_info.type == IPL_TYPE_NVME_DUMP) {
 261                 TRACE("type:   nvme\n");
 262                 TRACE("fid:    %x\n", ipl_info.data.nvme.fid);
 263                 TRACE("nsid:   %x\n", ipl_info.data.nvme.nsid);
 264         }
 265
 266         rc = sclp_sdias_init();
 267         if (rc)
 268                 goto fail;
 269
 270         rc = check_sdias();
 271         if (rc)
 272                 goto fail;
 273         hsa_available = 1;
 274
 275         rc = memcpy_hsa_kernel(&arch, __LC_AR_MODE_ID, 1);
 276         if (rc)
 277                 goto fail;
 278
 279         if (arch == ARCH_S390) {
 280                 pr_alert("The 64-bit dump tool cannot be used for a "
 281                          "32-bit system\n");
 282                 rc = -EINVAL;
 283                 goto fail;
 284         }
 285
 286         pr_alert("The dump process started for a 64-bit operating system\n");
 287         rc = init_cpu_info();
 288         if (rc)
 289                 goto fail;
 290
 291         rc = zcore_reipl_init();
 292         if (rc)
 293                 goto fail;
 294
 295         zcore_dir = debugfs_create_dir("zcore" , NULL);
 296         if (!zcore_dir) {
 297                 rc = -ENOMEM;
 298                 goto fail;
 299         }
 300         zcore_reipl_file = debugfs_create_file("reipl", S_IRUSR, zcore_dir,
 301                                                 NULL, &zcore_reipl_fops);
 302         if (!zcore_reipl_file) {
 303                 rc = -ENOMEM;
 304                 goto fail_dir;
 305         }
 306         zcore_hsa_file = debugfs_create_file("hsa", S_IRUSR|S_IWUSR, zcore_dir,
 307                                              NULL, &zcore_hsa_fops);
 308         if (!zcore_hsa_file) {
 309                 rc = -ENOMEM;
 310                 goto fail_reipl_file;
 311         }
 312         return 0;
 313
 314 fail_reipl_file:
 315         debugfs_remove(zcore_reipl_file);
 316 fail_dir:
 317         debugfs_remove(zcore_dir);
 318 fail:
 319         diag308(DIAG308_REL_HSA, NULL);
 320         return rc;
 321 }
 322 subsys_initcall(zcore_init);