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/panic_notifier.h>
  19 #include <linux/reboot.h>
  20
  21 #include <asm/asm-offsets.h>
  22 #include <asm/ipl.h>
  23 #include <asm/sclp.h>
  24 #include <asm/setup.h>
  25 #include <linux/uaccess.h>
  26 #include <asm/debug.h>
  27 #include <asm/processor.h>
  28 #include <asm/irqflags.h>
  29 #include <asm/checksum.h>
  30 #include <asm/os_info.h>
  31 #include <asm/switch_to.h>
  32 #include "sclp.h"
  33
  34 #define TRACE(x...) debug_sprintf_event(zcore_dbf, 1, x)
  35
  36 enum arch_id {
  37         ARCH_S390       = 0,
  38         ARCH_S390X      = 1,
  39 };
  40
  41 struct ipib_info {
  42         unsigned long   ipib;
  43         u32             checksum;
  44 }  __attribute__((packed));
  45
  46 static struct debug_info *zcore_dbf;
  47 static int hsa_available;
  48 static struct dentry *zcore_dir;
  49 static struct dentry *zcore_reipl_file;
  50 static struct dentry *zcore_hsa_file;
  51 static struct ipl_parameter_block *zcore_ipl_block;
  52
  53 static char hsa_buf[PAGE_SIZE] __aligned(PAGE_SIZE);
  54
  55 /*
  56  * Copy memory from HSA to user memory (not reentrant):
  57  *
  58  * @dest:  User buffer where memory should be copied to
  59  * @src:   Start address within HSA where data should be copied
  60  * @count: Size of buffer, which should be copied
  61  */
  62 int memcpy_hsa_user(void __user *dest, unsigned long src, size_t count)
  63 {
  64         unsigned long offset, bytes;
  65
  66         if (!hsa_available)
  67                 return -ENODATA;
  68
  69         while (count) {
  70                 if (sclp_sdias_copy(hsa_buf, src / PAGE_SIZE + 2, 1)) {
  71                         TRACE("sclp_sdias_copy() failed\n");
  72                         return -EIO;
  73                 }
  74                 offset = src % PAGE_SIZE;
  75                 bytes = min(PAGE_SIZE - offset, count);
  76                 if (copy_to_user(dest, hsa_buf + offset, bytes))
  77                         return -EFAULT;
  78                 src += bytes;
  79                 dest += bytes;
  80                 count -= bytes;
  81         }
  82         return 0;
  83 }
  84
  85 /*
  86  * Copy memory from HSA to kernel memory (not reentrant):
  87  *
  88  * @dest:  Kernel or user buffer where memory should be copied to
  89  * @src:   Start address within HSA where data should be copied
  90  * @count: Size of buffer, which should be copied
  91  */
  92 int memcpy_hsa_kernel(void *dest, unsigned long src, size_t count)
  93 {
  94         unsigned long offset, bytes;
  95
  96         if (!hsa_available)
  97                 return -ENODATA;
  98
  99         while (count) {
 100                 if (sclp_sdias_copy(hsa_buf, src / PAGE_SIZE + 2, 1)) {
 101                         TRACE("sclp_sdias_copy() failed\n");
 102                         return -EIO;
 103                 }
 104                 offset = src % PAGE_SIZE;
 105                 bytes = min(PAGE_SIZE - offset, count);
 106                 memcpy(dest, hsa_buf + offset, bytes);
 107                 src += bytes;
 108                 dest += bytes;
 109                 count -= bytes;
 110         }
 111         return 0;
 112 }
 113
 114 static int __init init_cpu_info(void)
 115 {
 116         struct save_area *sa;
 117
 118         /* get info for boot cpu from lowcore, stored in the HSA */
 119         sa = save_area_boot_cpu();
 120         if (!sa)
 121                 return -ENOMEM;
 122         if (memcpy_hsa_kernel(hsa_buf, __LC_FPREGS_SAVE_AREA, 512) < 0) {
 123                 TRACE("could not copy from HSA\n");
 124                 return -EIO;
 125         }
 126         save_area_add_regs(sa, hsa_buf); /* vx registers are saved in smp.c */
 127         return 0;
 128 }
 129
 130 /*
 131  * Release the HSA
 132  */
 133 static void release_hsa(void)
 134 {
 135         diag308(DIAG308_REL_HSA, NULL);
 136         hsa_available = 0;
 137 }
 138
 139 static ssize_t zcore_reipl_write(struct file *filp, const char __user *buf,
 140                                  size_t count, loff_t *ppos)
 141 {
 142         if (zcore_ipl_block) {
 143                 diag308(DIAG308_SET, zcore_ipl_block);
 144                 diag308(DIAG308_LOAD_CLEAR, NULL);
 145         }
 146         return count;
 147 }
 148
 149 static int zcore_reipl_open(struct inode *inode, struct file *filp)
 150 {
 151         return stream_open(inode, filp);
 152 }
 153
 154 static int zcore_reipl_release(struct inode *inode, struct file *filp)
 155 {
 156         return 0;
 157 }
 158
 159 static const struct file_operations zcore_reipl_fops = {
 160         .owner          = THIS_MODULE,
 161         .write          = zcore_reipl_write,
 162         .open           = zcore_reipl_open,
 163         .release        = zcore_reipl_release,
 164         .llseek         = no_llseek,
 165 };
 166
 167 static ssize_t zcore_hsa_read(struct file *filp, char __user *buf,
 168                               size_t count, loff_t *ppos)
 169 {
 170         static char str[18];
 171
 172         if (hsa_available)
 173                 snprintf(str, sizeof(str), "%lx\n", sclp.hsa_size);
 174         else
 175                 snprintf(str, sizeof(str), "0\n");
 176         return simple_read_from_buffer(buf, count, ppos, str, strlen(str));
 177 }
 178
 179 static ssize_t zcore_hsa_write(struct file *filp, const char __user *buf,
 180                                size_t count, loff_t *ppos)
 181 {
 182         char value;
 183
 184         if (*ppos != 0)
 185                 return -EPIPE;
 186         if (copy_from_user(&value, buf, 1))
 187                 return -EFAULT;
 188         if (value != '0')
 189                 return -EINVAL;
 190         release_hsa();
 191         return count;
 192 }
 193
 194 static const struct file_operations zcore_hsa_fops = {
 195         .owner          = THIS_MODULE,
 196         .write          = zcore_hsa_write,
 197         .read           = zcore_hsa_read,
 198         .open           = nonseekable_open,
 199         .llseek         = no_llseek,
 200 };
 201
 202 static int __init check_sdias(void)
 203 {
 204         if (!sclp.hsa_size) {
 205                 TRACE("Could not determine HSA size\n");
 206                 return -ENODEV;
 207         }
 208         return 0;
 209 }
 210
 211 /*
 212  * Provide IPL parameter information block from either HSA or memory
 213  * for future reipl
 214  */
 215 static int __init zcore_reipl_init(void)
 216 {
 217         struct ipib_info ipib_info;
 218         int rc;
 219
 220         rc = memcpy_hsa_kernel(&ipib_info, __LC_DUMP_REIPL, sizeof(ipib_info));
 221         if (rc)
 222                 return rc;
 223         if (ipib_info.ipib == 0)
 224                 return 0;
 225         zcore_ipl_block = (void *) __get_free_page(GFP_KERNEL);
 226         if (!zcore_ipl_block)
 227                 return -ENOMEM;
 228         if (ipib_info.ipib < sclp.hsa_size)
 229                 rc = memcpy_hsa_kernel(zcore_ipl_block, ipib_info.ipib,
 230                                        PAGE_SIZE);
 231         else
 232                 rc = memcpy_real(zcore_ipl_block, (void *) ipib_info.ipib,
 233                                  PAGE_SIZE);
 234         if (rc || (__force u32)csum_partial(zcore_ipl_block, zcore_ipl_block->hdr.len, 0) !=
 235             ipib_info.checksum) {
 236                 TRACE("Checksum does not match\n");
 237                 free_page((unsigned long) zcore_ipl_block);
 238                 zcore_ipl_block = NULL;
 239         }
 240         return 0;
 241 }
 242
 243 static int zcore_reboot_and_on_panic_handler(struct notifier_block *self,
 244                                              unsigned long         event,
 245                                              void                  *data)
 246 {
 247         if (hsa_available)
 248                 release_hsa();
 249
 250         return NOTIFY_OK;
 251 }
 252
 253 static struct notifier_block zcore_reboot_notifier = {
 254         .notifier_call  = zcore_reboot_and_on_panic_handler,
 255         /* we need to be notified before reipl and kdump */
 256         .priority       = INT_MAX,
 257 };
 258
 259 static struct notifier_block zcore_on_panic_notifier = {
 260         .notifier_call  = zcore_reboot_and_on_panic_handler,
 261         /* we need to be notified before reipl and kdump */
 262         .priority       = INT_MAX,
 263 };
 264
 265 static int __init zcore_init(void)
 266 {
 267         unsigned char arch;
 268         int rc;
 269
 270         if (!is_ipl_type_dump())
 271                 return -ENODATA;
 272         if (OLDMEM_BASE)
 273                 return -ENODATA;
 274
 275         zcore_dbf = debug_register("zcore", 4, 1, 4 * sizeof(long));
 276         debug_register_view(zcore_dbf, &debug_sprintf_view);
 277         debug_set_level(zcore_dbf, 6);
 278
 279         if (ipl_info.type == IPL_TYPE_FCP_DUMP) {
 280                 TRACE("type:   fcp\n");
 281                 TRACE("devno:  %x\n", ipl_info.data.fcp.dev_id.devno);
 282                 TRACE("wwpn:   %llx\n", (unsigned long long) ipl_info.data.fcp.wwpn);
 283                 TRACE("lun:    %llx\n", (unsigned long long) ipl_info.data.fcp.lun);
 284         } else if (ipl_info.type == IPL_TYPE_NVME_DUMP) {
 285                 TRACE("type:   nvme\n");
 286                 TRACE("fid:    %x\n", ipl_info.data.nvme.fid);
 287                 TRACE("nsid:   %x\n", ipl_info.data.nvme.nsid);
 288         }
 289
 290         rc = sclp_sdias_init();
 291         if (rc)
 292                 goto fail;
 293
 294         rc = check_sdias();
 295         if (rc)
 296                 goto fail;
 297         hsa_available = 1;
 298
 299         rc = memcpy_hsa_kernel(&arch, __LC_AR_MODE_ID, 1);
 300         if (rc)
 301                 goto fail;
 302
 303         if (arch == ARCH_S390) {
 304                 pr_alert("The 64-bit dump tool cannot be used for a "
 305                          "32-bit system\n");
 306                 rc = -EINVAL;
 307                 goto fail;
 308         }
 309
 310         pr_alert("The dump process started for a 64-bit operating system\n");
 311         rc = init_cpu_info();
 312         if (rc)
 313                 goto fail;
 314
 315         rc = zcore_reipl_init();
 316         if (rc)
 317                 goto fail;
 318
 319         zcore_dir = debugfs_create_dir("zcore" , NULL);
 320         zcore_reipl_file = debugfs_create_file("reipl", S_IRUSR, zcore_dir,
 321                                                 NULL, &zcore_reipl_fops);
 322         zcore_hsa_file = debugfs_create_file("hsa", S_IRUSR|S_IWUSR, zcore_dir,
 323                                              NULL, &zcore_hsa_fops);
 324
 325         register_reboot_notifier(&zcore_reboot_notifier);
 326         atomic_notifier_chain_register(&panic_notifier_list, &zcore_on_panic_notifier);
 327
 328         return 0;
 329 fail:
 330         diag308(DIAG308_REL_HSA, NULL);
 331         return rc;
 332 }
 333 subsys_initcall(zcore_init);