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 }; 169 170 static ssize_t zcore_hsa_read(struct file *filp, char __user *buf, 171 size_t count, loff_t *ppos) 172 { 173 static char str[18]; 174 175 if (hsa_available) 176 snprintf(str, sizeof(str), "%lx\n", sclp.hsa_size); 177 else 178 snprintf(str, sizeof(str), "0\n"); 179 return simple_read_from_buffer(buf, count, ppos, str, strlen(str)); 180 } 181 182 static ssize_t zcore_hsa_write(struct file *filp, const char __user *buf, 183 size_t count, loff_t *ppos) 184 { 185 char value; 186 187 if (*ppos != 0) 188 return -EPIPE; 189 if (copy_from_user(&value, buf, 1)) 190 return -EFAULT; 191 if (value != '0') 192 return -EINVAL; 193 release_hsa(); 194 return count; 195 } 196 197 static const struct file_operations zcore_hsa_fops = { 198 .owner = THIS_MODULE, 199 .write = zcore_hsa_write, 200 .read = zcore_hsa_read, 201 .open = nonseekable_open, 202 }; 203 204 static int __init check_sdias(void) 205 { 206 if (!sclp.hsa_size) { 207 TRACE("Could not determine HSA size\n"); 208 return -ENODEV; 209 } 210 return 0; 211 } 212 213 /* 214 * Provide IPL parameter information block from either HSA or memory 215 * for future reipl 216 */ 217 static int __init zcore_reipl_init(void) 218 { 219 struct os_info_entry *entry; 220 struct ipib_info ipib_info; 221 unsigned long os_info_addr; 222 struct os_info *os_info; 223 int rc; 224 225 rc = memcpy_hsa_kernel(&ipib_info, __LC_DUMP_REIPL, sizeof(ipib_info)); 226 if (rc) 227 return rc; 228 if (ipib_info.ipib == 0) 229 return 0; 230 zcore_ipl_block = (void *) __get_free_page(GFP_KERNEL); 231 if (!zcore_ipl_block) 232 return -ENOMEM; 233 if (ipib_info.ipib < sclp.hsa_size) 234 rc = memcpy_hsa_kernel(zcore_ipl_block, ipib_info.ipib, 235 PAGE_SIZE); 236 else 237 rc = memcpy_real(zcore_ipl_block, ipib_info.ipib, PAGE_SIZE); 238 if (rc || (__force u32)csum_partial(zcore_ipl_block, zcore_ipl_block->hdr.len, 0) != 239 ipib_info.checksum) { 240 TRACE("Checksum does not match\n"); 241 free_page((unsigned long) zcore_ipl_block); 242 zcore_ipl_block = NULL; 243 } 244 /* 245 * Read the bit-flags field from os_info flags entry. 246 * Return zero even for os_info read or entry checksum errors in order 247 * to continue dump processing, considering that os_info could be 248 * corrupted on the panicked system. 249 */ 250 os_info = (void *)__get_free_page(GFP_KERNEL); 251 if (!os_info) 252 return -ENOMEM; 253 rc = memcpy_hsa_kernel(&os_info_addr, __LC_OS_INFO, sizeof(os_info_addr)); 254 if (rc) 255 goto out; 256 if (os_info_addr < sclp.hsa_size) 257 rc = memcpy_hsa_kernel(os_info, os_info_addr, PAGE_SIZE); 258 else 259 rc = memcpy_real(os_info, os_info_addr, PAGE_SIZE); 260 if (rc || os_info_csum(os_info) != os_info->csum) 261 goto out; 262 entry = &os_info->entry[OS_INFO_FLAGS_ENTRY]; 263 if (entry->addr && entry->size) { 264 if (entry->addr < sclp.hsa_size) 265 rc = memcpy_hsa_kernel(&os_info_flags, entry->addr, sizeof(os_info_flags)); 266 else 267 rc = memcpy_real(&os_info_flags, entry->addr, sizeof(os_info_flags)); 268 if (rc || (__force u32)csum_partial(&os_info_flags, entry->size, 0) != entry->csum) 269 os_info_flags = 0; 270 } 271 out: 272 free_page((unsigned long)os_info); 273 return 0; 274 } 275 276 static int zcore_reboot_and_on_panic_handler(struct notifier_block *self, 277 unsigned long event, 278 void *data) 279 { 280 if (hsa_available) 281 release_hsa(); 282 283 return NOTIFY_OK; 284 } 285 286 static struct notifier_block zcore_reboot_notifier = { 287 .notifier_call = zcore_reboot_and_on_panic_handler, 288 /* we need to be notified before reipl and kdump */ 289 .priority = INT_MAX, 290 }; 291 292 static struct notifier_block zcore_on_panic_notifier = { 293 .notifier_call = zcore_reboot_and_on_panic_handler, 294 /* we need to be notified before reipl and kdump */ 295 .priority = INT_MAX, 296 }; 297 298 static int __init zcore_init(void) 299 { 300 unsigned char arch; 301 int rc; 302 303 if (!is_ipl_type_dump()) 304 return -ENODATA; 305 if (oldmem_data.start) 306 return -ENODATA; 307 308 zcore_dbf = debug_register("zcore", 4, 1, 4 * sizeof(long)); 309 debug_register_view(zcore_dbf, &debug_sprintf_view); 310 debug_set_level(zcore_dbf, 6); 311 312 if (ipl_info.type == IPL_TYPE_FCP_DUMP) { 313 TRACE("type: fcp\n"); 314 TRACE("devno: %x\n", ipl_info.data.fcp.dev_id.devno); 315 TRACE("wwpn: %llx\n", (unsigned long long) ipl_info.data.fcp.wwpn); 316 TRACE("lun: %llx\n", (unsigned long long) ipl_info.data.fcp.lun); 317 } else if (ipl_info.type == IPL_TYPE_NVME_DUMP) { 318 TRACE("type: nvme\n"); 319 TRACE("fid: %x\n", ipl_info.data.nvme.fid); 320 TRACE("nsid: %x\n", ipl_info.data.nvme.nsid); 321 } else if (ipl_info.type == IPL_TYPE_ECKD_DUMP) { 322 TRACE("type: eckd\n"); 323 TRACE("devno: %x\n", ipl_info.data.eckd.dev_id.devno); 324 TRACE("ssid: %x\n", ipl_info.data.eckd.dev_id.ssid); 325 } 326 327 rc = sclp_sdias_init(); 328 if (rc) 329 goto fail; 330 331 rc = check_sdias(); 332 if (rc) 333 goto fail; 334 hsa_available = 1; 335 336 rc = memcpy_hsa_kernel(&arch, __LC_AR_MODE_ID, 1); 337 if (rc) 338 goto fail; 339 340 if (arch == ARCH_S390) { 341 pr_alert("The 64-bit dump tool cannot be used for a " 342 "32-bit system\n"); 343 rc = -EINVAL; 344 goto fail; 345 } 346 347 pr_alert("The dump process started for a 64-bit operating system\n"); 348 rc = init_cpu_info(); 349 if (rc) 350 goto fail; 351 352 rc = zcore_reipl_init(); 353 if (rc) 354 goto fail; 355 356 zcore_dir = debugfs_create_dir("zcore" , NULL); 357 zcore_reipl_file = debugfs_create_file("reipl", S_IRUSR, zcore_dir, 358 NULL, &zcore_reipl_fops); 359 zcore_hsa_file = debugfs_create_file("hsa", S_IRUSR|S_IWUSR, zcore_dir, 360 NULL, &zcore_hsa_fops); 361 362 register_reboot_notifier(&zcore_reboot_notifier); 363 atomic_notifier_chain_register(&panic_notifier_list, &zcore_on_panic_notifier); 364 365 return 0; 366 fail: 367 diag308(DIAG308_REL_HSA, NULL); 368 return rc; 369 } 370 subsys_initcall(zcore_init); 371