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 #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/switch_to.h> 33 #include <asm/maccess.h> 34 #include "sclp.h" 35 36 #define TRACE(x...) debug_sprintf_event(zcore_dbf, 1, x) 37 38 enum arch_id { 39 ARCH_S390 = 0, 40 ARCH_S390X = 1, 41 }; 42 43 struct ipib_info { 44 unsigned long ipib; 45 u32 checksum; 46 } __attribute__((packed)); 47 48 static struct debug_info *zcore_dbf; 49 static int hsa_available; 50 static struct dentry *zcore_dir; 51 static struct dentry *zcore_reipl_file; 52 static struct dentry *zcore_hsa_file; 53 static struct ipl_parameter_block *zcore_ipl_block; 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, WRITE, &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 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, ipib_info.ipib, PAGE_SIZE); 231 if (rc || (__force u32)csum_partial(zcore_ipl_block, zcore_ipl_block->hdr.len, 0) != 232 ipib_info.checksum) { 233 TRACE("Checksum does not match\n"); 234 free_page((unsigned long) zcore_ipl_block); 235 zcore_ipl_block = NULL; 236 } 237 return 0; 238 } 239 240 static int zcore_reboot_and_on_panic_handler(struct notifier_block *self, 241 unsigned long event, 242 void *data) 243 { 244 if (hsa_available) 245 release_hsa(); 246 247 return NOTIFY_OK; 248 } 249 250 static struct notifier_block zcore_reboot_notifier = { 251 .notifier_call = zcore_reboot_and_on_panic_handler, 252 /* we need to be notified before reipl and kdump */ 253 .priority = INT_MAX, 254 }; 255 256 static struct notifier_block zcore_on_panic_notifier = { 257 .notifier_call = zcore_reboot_and_on_panic_handler, 258 /* we need to be notified before reipl and kdump */ 259 .priority = INT_MAX, 260 }; 261 262 static int __init zcore_init(void) 263 { 264 unsigned char arch; 265 int rc; 266 267 if (!is_ipl_type_dump()) 268 return -ENODATA; 269 if (oldmem_data.start) 270 return -ENODATA; 271 272 zcore_dbf = debug_register("zcore", 4, 1, 4 * sizeof(long)); 273 debug_register_view(zcore_dbf, &debug_sprintf_view); 274 debug_set_level(zcore_dbf, 6); 275 276 if (ipl_info.type == IPL_TYPE_FCP_DUMP) { 277 TRACE("type: fcp\n"); 278 TRACE("devno: %x\n", ipl_info.data.fcp.dev_id.devno); 279 TRACE("wwpn: %llx\n", (unsigned long long) ipl_info.data.fcp.wwpn); 280 TRACE("lun: %llx\n", (unsigned long long) ipl_info.data.fcp.lun); 281 } else if (ipl_info.type == IPL_TYPE_NVME_DUMP) { 282 TRACE("type: nvme\n"); 283 TRACE("fid: %x\n", ipl_info.data.nvme.fid); 284 TRACE("nsid: %x\n", ipl_info.data.nvme.nsid); 285 } 286 287 rc = sclp_sdias_init(); 288 if (rc) 289 goto fail; 290 291 rc = check_sdias(); 292 if (rc) 293 goto fail; 294 hsa_available = 1; 295 296 rc = memcpy_hsa_kernel(&arch, __LC_AR_MODE_ID, 1); 297 if (rc) 298 goto fail; 299 300 if (arch == ARCH_S390) { 301 pr_alert("The 64-bit dump tool cannot be used for a " 302 "32-bit system\n"); 303 rc = -EINVAL; 304 goto fail; 305 } 306 307 pr_alert("The dump process started for a 64-bit operating system\n"); 308 rc = init_cpu_info(); 309 if (rc) 310 goto fail; 311 312 rc = zcore_reipl_init(); 313 if (rc) 314 goto fail; 315 316 zcore_dir = debugfs_create_dir("zcore" , NULL); 317 zcore_reipl_file = debugfs_create_file("reipl", S_IRUSR, zcore_dir, 318 NULL, &zcore_reipl_fops); 319 zcore_hsa_file = debugfs_create_file("hsa", S_IRUSR|S_IWUSR, zcore_dir, 320 NULL, &zcore_hsa_fops); 321 322 register_reboot_notifier(&zcore_reboot_notifier); 323 atomic_notifier_chain_register(&panic_notifier_list, &zcore_on_panic_notifier); 324 325 return 0; 326 fail: 327 diag308(DIAG308_REL_HSA, NULL); 328 return rc; 329 } 330 subsys_initcall(zcore_init); 331