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 pr_fmt(fmt) "zdump: " fmt 13 14 #include <linux/init.h> 15 #include <linux/slab.h> 16 #include <linux/debugfs.h> 17 #include <linux/panic_notifier.h> 18 #include <linux/reboot.h> 19 #include <linux/uio.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/maccess.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 static unsigned long os_info_flags; 53 54 static DEFINE_MUTEX(hsa_buf_mutex); 55 static char hsa_buf[PAGE_SIZE] __aligned(PAGE_SIZE); 56 57 /* 58 * Copy memory from HSA to iterator (not reentrant): 59 * 60 * @iter: Iterator where memory should be copied to 61 * @src: Start address within HSA where data should be copied 62 * @count: Size of buffer, which should be copied 63 */ 64 size_t memcpy_hsa_iter(struct iov_iter *iter, unsigned long src, size_t count) 65 { 66 size_t bytes, copied, res = 0; 67 unsigned long offset; 68 69 if (!hsa_available) 70 return 0; 71 72 mutex_lock(&hsa_buf_mutex); 73 while (count) { 74 if (sclp_sdias_copy(hsa_buf, src / PAGE_SIZE + 2, 1)) { 75 TRACE("sclp_sdias_copy() failed\n"); 76 break; 77 } 78 offset = src % PAGE_SIZE; 79 bytes = min(PAGE_SIZE - offset, count); 80 copied = copy_to_iter(hsa_buf + offset, bytes, iter); 81 count -= copied; 82 src += copied; 83 res += copied; 84 if (copied < bytes) 85 break; 86 } 87 mutex_unlock(&hsa_buf_mutex); 88 return res; 89 } 90 91 /* 92 * Copy memory from HSA to kernel memory (not reentrant): 93 * 94 * @dest: Kernel or user buffer where memory should be copied to 95 * @src: Start address within HSA where data should be copied 96 * @count: Size of buffer, which should be copied 97 */ 98 static inline int memcpy_hsa_kernel(void *dst, unsigned long src, size_t count) 99 { 100 struct iov_iter iter; 101 struct kvec kvec; 102 103 kvec.iov_base = dst; 104 kvec.iov_len = count; 105 iov_iter_kvec(&iter, ITER_DEST, &kvec, 1, count); 106 if (memcpy_hsa_iter(&iter, src, count) < count) 107 return -EIO; 108 return 0; 109 } 110 111 static int __init init_cpu_info(void) 112 { 113 struct save_area *sa; 114 115 /* get info for boot cpu from lowcore, stored in the HSA */ 116 sa = save_area_boot_cpu(); 117 if (!sa) 118 return -ENOMEM; 119 if (memcpy_hsa_kernel(hsa_buf, __LC_FPREGS_SAVE_AREA, 512) < 0) { 120 TRACE("could not copy from HSA\n"); 121 return -EIO; 122 } 123 save_area_add_regs(sa, hsa_buf); /* vx registers are saved in smp.c */ 124 return 0; 125 } 126 127 /* 128 * Release the HSA 129 */ 130 static void release_hsa(void) 131 { 132 diag308(DIAG308_REL_HSA, NULL); 133 hsa_available = 0; 134 } 135 136 static ssize_t zcore_reipl_write(struct file *filp, const char __user *buf, 137 size_t count, loff_t *ppos) 138 { 139 if (zcore_ipl_block) { 140 diag308(DIAG308_SET, zcore_ipl_block); 141 if (os_info_flags & OS_INFO_FLAG_REIPL_CLEAR) 142 diag308(DIAG308_LOAD_CLEAR, NULL); 143 /* Use special diag308 subcode for CCW normal ipl */ 144 if (zcore_ipl_block->pb0_hdr.pbt == IPL_PBT_CCW) 145 diag308(DIAG308_LOAD_NORMAL_DUMP, NULL); 146 else 147 diag308(DIAG308_LOAD_NORMAL, NULL); 148 } 149 return count; 150 } 151 152 static int zcore_reipl_open(struct inode *inode, struct file *filp) 153 { 154 return stream_open(inode, filp); 155 } 156 157 static int zcore_reipl_release(struct inode *inode, struct file *filp) 158 { 159 return 0; 160 } 161 162 static const struct file_operations zcore_reipl_fops = { 163 .owner = THIS_MODULE, 164 .write = zcore_reipl_write, 165 .open = zcore_reipl_open, 166 .release = zcore_reipl_release, 167 }; 168 169 static ssize_t zcore_hsa_read(struct file *filp, char __user *buf, 170 size_t count, loff_t *ppos) 171 { 172 static char str[18]; 173 174 if (hsa_available) 175 snprintf(str, sizeof(str), "%lx\n", sclp.hsa_size); 176 else 177 snprintf(str, sizeof(str), "0\n"); 178 return simple_read_from_buffer(buf, count, ppos, str, strlen(str)); 179 } 180 181 static ssize_t zcore_hsa_write(struct file *filp, const char __user *buf, 182 size_t count, loff_t *ppos) 183 { 184 char value; 185 186 if (*ppos != 0) 187 return -EPIPE; 188 if (copy_from_user(&value, buf, 1)) 189 return -EFAULT; 190 if (value != '0') 191 return -EINVAL; 192 release_hsa(); 193 return count; 194 } 195 196 static const struct file_operations zcore_hsa_fops = { 197 .owner = THIS_MODULE, 198 .write = zcore_hsa_write, 199 .read = zcore_hsa_read, 200 .open = nonseekable_open, 201 }; 202 203 static int __init check_sdias(void) 204 { 205 if (!sclp.hsa_size) { 206 TRACE("Could not determine HSA size\n"); 207 return -ENODEV; 208 } 209 return 0; 210 } 211 212 /* 213 * Provide IPL parameter information block from either HSA or memory 214 * for future reipl 215 */ 216 static int __init zcore_reipl_init(void) 217 { 218 struct os_info_entry *entry; 219 struct ipib_info ipib_info; 220 unsigned long os_info_addr; 221 struct os_info *os_info; 222 int rc; 223 224 rc = memcpy_hsa_kernel(&ipib_info, __LC_DUMP_REIPL, sizeof(ipib_info)); 225 if (rc) 226 return rc; 227 if (ipib_info.ipib == 0) 228 return 0; 229 zcore_ipl_block = (void *) __get_free_page(GFP_KERNEL); 230 if (!zcore_ipl_block) 231 return -ENOMEM; 232 if (ipib_info.ipib < sclp.hsa_size) 233 rc = memcpy_hsa_kernel(zcore_ipl_block, ipib_info.ipib, 234 PAGE_SIZE); 235 else 236 rc = memcpy_real(zcore_ipl_block, ipib_info.ipib, PAGE_SIZE); 237 if (rc || (__force u32)csum_partial(zcore_ipl_block, zcore_ipl_block->hdr.len, 0) != 238 ipib_info.checksum) { 239 TRACE("Checksum does not match\n"); 240 free_page((unsigned long) zcore_ipl_block); 241 zcore_ipl_block = NULL; 242 } 243 /* 244 * Read the bit-flags field from os_info flags entry. 245 * Return zero even for os_info read or entry checksum errors in order 246 * to continue dump processing, considering that os_info could be 247 * corrupted on the panicked system. 248 */ 249 os_info = (void *)__get_free_page(GFP_KERNEL); 250 if (!os_info) 251 return -ENOMEM; 252 rc = memcpy_hsa_kernel(&os_info_addr, __LC_OS_INFO, sizeof(os_info_addr)); 253 if (rc) 254 goto out; 255 if (os_info_addr < sclp.hsa_size) 256 rc = memcpy_hsa_kernel(os_info, os_info_addr, PAGE_SIZE); 257 else 258 rc = memcpy_real(os_info, os_info_addr, PAGE_SIZE); 259 if (rc || os_info_csum(os_info) != os_info->csum) 260 goto out; 261 entry = &os_info->entry[OS_INFO_FLAGS_ENTRY]; 262 if (entry->addr && entry->size) { 263 if (entry->addr < sclp.hsa_size) 264 rc = memcpy_hsa_kernel(&os_info_flags, entry->addr, sizeof(os_info_flags)); 265 else 266 rc = memcpy_real(&os_info_flags, entry->addr, sizeof(os_info_flags)); 267 if (rc || (__force u32)csum_partial(&os_info_flags, entry->size, 0) != entry->csum) 268 os_info_flags = 0; 269 } 270 out: 271 free_page((unsigned long)os_info); 272 return 0; 273 } 274 275 static int zcore_reboot_and_on_panic_handler(struct notifier_block *self, 276 unsigned long event, 277 void *data) 278 { 279 if (hsa_available) 280 release_hsa(); 281 282 return NOTIFY_OK; 283 } 284 285 static struct notifier_block zcore_reboot_notifier = { 286 .notifier_call = zcore_reboot_and_on_panic_handler, 287 /* we need to be notified before reipl and kdump */ 288 .priority = INT_MAX, 289 }; 290 291 static struct notifier_block zcore_on_panic_notifier = { 292 .notifier_call = zcore_reboot_and_on_panic_handler, 293 /* we need to be notified before reipl and kdump */ 294 .priority = INT_MAX, 295 }; 296 297 static int __init zcore_init(void) 298 { 299 unsigned char arch; 300 int rc; 301 302 if (!is_ipl_type_dump()) 303 return -ENODATA; 304 if (oldmem_data.start) 305 return -ENODATA; 306 307 zcore_dbf = debug_register("zcore", 4, 1, 4 * sizeof(long)); 308 debug_register_view(zcore_dbf, &debug_sprintf_view); 309 debug_set_level(zcore_dbf, 6); 310 311 if (ipl_info.type == IPL_TYPE_FCP_DUMP) { 312 TRACE("type: fcp\n"); 313 TRACE("devno: %x\n", ipl_info.data.fcp.dev_id.devno); 314 TRACE("wwpn: %llx\n", (unsigned long long) ipl_info.data.fcp.wwpn); 315 TRACE("lun: %llx\n", (unsigned long long) ipl_info.data.fcp.lun); 316 } else if (ipl_info.type == IPL_TYPE_NVME_DUMP) { 317 TRACE("type: nvme\n"); 318 TRACE("fid: %x\n", ipl_info.data.nvme.fid); 319 TRACE("nsid: %x\n", ipl_info.data.nvme.nsid); 320 } else if (ipl_info.type == IPL_TYPE_ECKD_DUMP) { 321 TRACE("type: eckd\n"); 322 TRACE("devno: %x\n", ipl_info.data.eckd.dev_id.devno); 323 TRACE("ssid: %x\n", ipl_info.data.eckd.dev_id.ssid); 324 } 325 326 rc = sclp_sdias_init(); 327 if (rc) 328 goto fail; 329 330 rc = check_sdias(); 331 if (rc) 332 goto fail; 333 hsa_available = 1; 334 335 rc = memcpy_hsa_kernel(&arch, __LC_AR_MODE_ID, 1); 336 if (rc) 337 goto fail; 338 339 if (arch == ARCH_S390) { 340 pr_alert("The 64-bit dump tool cannot be used for a " 341 "32-bit system\n"); 342 rc = -EINVAL; 343 goto fail; 344 } 345 346 pr_alert("The dump process started for a 64-bit operating system\n"); 347 rc = init_cpu_info(); 348 if (rc) 349 goto fail; 350 351 rc = zcore_reipl_init(); 352 if (rc) 353 goto fail; 354 355 zcore_dir = debugfs_create_dir("zcore" , NULL); 356 zcore_reipl_file = debugfs_create_file("reipl", S_IRUSR, zcore_dir, 357 NULL, &zcore_reipl_fops); 358 zcore_hsa_file = debugfs_create_file("hsa", S_IRUSR|S_IWUSR, zcore_dir, 359 NULL, &zcore_hsa_fops); 360 361 register_reboot_notifier(&zcore_reboot_notifier); 362 atomic_notifier_chain_register(&panic_notifier_list, &zcore_on_panic_notifier); 363 364 return 0; 365 fail: 366 diag308(DIAG308_REL_HSA, NULL); 367 return rc; 368 } 369 subsys_initcall(zcore_init); 370