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 "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 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, WRITE, &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 diag308(DIAG308_LOAD_CLEAR, NULL); 142 } 143 return count; 144 } 145 146 static int zcore_reipl_open(struct inode *inode, struct file *filp) 147 { 148 return stream_open(inode, filp); 149 } 150 151 static int zcore_reipl_release(struct inode *inode, struct file *filp) 152 { 153 return 0; 154 } 155 156 static const struct file_operations zcore_reipl_fops = { 157 .owner = THIS_MODULE, 158 .write = zcore_reipl_write, 159 .open = zcore_reipl_open, 160 .release = zcore_reipl_release, 161 .llseek = no_llseek, 162 }; 163 164 static ssize_t zcore_hsa_read(struct file *filp, char __user *buf, 165 size_t count, loff_t *ppos) 166 { 167 static char str[18]; 168 169 if (hsa_available) 170 snprintf(str, sizeof(str), "%lx\n", sclp.hsa_size); 171 else 172 snprintf(str, sizeof(str), "0\n"); 173 return simple_read_from_buffer(buf, count, ppos, str, strlen(str)); 174 } 175 176 static ssize_t zcore_hsa_write(struct file *filp, const char __user *buf, 177 size_t count, loff_t *ppos) 178 { 179 char value; 180 181 if (*ppos != 0) 182 return -EPIPE; 183 if (copy_from_user(&value, buf, 1)) 184 return -EFAULT; 185 if (value != '0') 186 return -EINVAL; 187 release_hsa(); 188 return count; 189 } 190 191 static const struct file_operations zcore_hsa_fops = { 192 .owner = THIS_MODULE, 193 .write = zcore_hsa_write, 194 .read = zcore_hsa_read, 195 .open = nonseekable_open, 196 .llseek = no_llseek, 197 }; 198 199 static int __init check_sdias(void) 200 { 201 if (!sclp.hsa_size) { 202 TRACE("Could not determine HSA size\n"); 203 return -ENODEV; 204 } 205 return 0; 206 } 207 208 /* 209 * Provide IPL parameter information block from either HSA or memory 210 * for future reipl 211 */ 212 static int __init zcore_reipl_init(void) 213 { 214 struct ipib_info ipib_info; 215 int rc; 216 217 rc = memcpy_hsa_kernel(&ipib_info, __LC_DUMP_REIPL, sizeof(ipib_info)); 218 if (rc) 219 return rc; 220 if (ipib_info.ipib == 0) 221 return 0; 222 zcore_ipl_block = (void *) __get_free_page(GFP_KERNEL); 223 if (!zcore_ipl_block) 224 return -ENOMEM; 225 if (ipib_info.ipib < sclp.hsa_size) 226 rc = memcpy_hsa_kernel(zcore_ipl_block, ipib_info.ipib, 227 PAGE_SIZE); 228 else 229 rc = memcpy_real(zcore_ipl_block, ipib_info.ipib, PAGE_SIZE); 230 if (rc || (__force u32)csum_partial(zcore_ipl_block, zcore_ipl_block->hdr.len, 0) != 231 ipib_info.checksum) { 232 TRACE("Checksum does not match\n"); 233 free_page((unsigned long) zcore_ipl_block); 234 zcore_ipl_block = NULL; 235 } 236 return 0; 237 } 238 239 static int zcore_reboot_and_on_panic_handler(struct notifier_block *self, 240 unsigned long event, 241 void *data) 242 { 243 if (hsa_available) 244 release_hsa(); 245 246 return NOTIFY_OK; 247 } 248 249 static struct notifier_block zcore_reboot_notifier = { 250 .notifier_call = zcore_reboot_and_on_panic_handler, 251 /* we need to be notified before reipl and kdump */ 252 .priority = INT_MAX, 253 }; 254 255 static struct notifier_block zcore_on_panic_notifier = { 256 .notifier_call = zcore_reboot_and_on_panic_handler, 257 /* we need to be notified before reipl and kdump */ 258 .priority = INT_MAX, 259 }; 260 261 static int __init zcore_init(void) 262 { 263 unsigned char arch; 264 int rc; 265 266 if (!is_ipl_type_dump()) 267 return -ENODATA; 268 if (oldmem_data.start) 269 return -ENODATA; 270 271 zcore_dbf = debug_register("zcore", 4, 1, 4 * sizeof(long)); 272 debug_register_view(zcore_dbf, &debug_sprintf_view); 273 debug_set_level(zcore_dbf, 6); 274 275 if (ipl_info.type == IPL_TYPE_FCP_DUMP) { 276 TRACE("type: fcp\n"); 277 TRACE("devno: %x\n", ipl_info.data.fcp.dev_id.devno); 278 TRACE("wwpn: %llx\n", (unsigned long long) ipl_info.data.fcp.wwpn); 279 TRACE("lun: %llx\n", (unsigned long long) ipl_info.data.fcp.lun); 280 } else if (ipl_info.type == IPL_TYPE_NVME_DUMP) { 281 TRACE("type: nvme\n"); 282 TRACE("fid: %x\n", ipl_info.data.nvme.fid); 283 TRACE("nsid: %x\n", ipl_info.data.nvme.nsid); 284 } 285 286 rc = sclp_sdias_init(); 287 if (rc) 288 goto fail; 289 290 rc = check_sdias(); 291 if (rc) 292 goto fail; 293 hsa_available = 1; 294 295 rc = memcpy_hsa_kernel(&arch, __LC_AR_MODE_ID, 1); 296 if (rc) 297 goto fail; 298 299 if (arch == ARCH_S390) { 300 pr_alert("The 64-bit dump tool cannot be used for a " 301 "32-bit system\n"); 302 rc = -EINVAL; 303 goto fail; 304 } 305 306 pr_alert("The dump process started for a 64-bit operating system\n"); 307 rc = init_cpu_info(); 308 if (rc) 309 goto fail; 310 311 rc = zcore_reipl_init(); 312 if (rc) 313 goto fail; 314 315 zcore_dir = debugfs_create_dir("zcore" , NULL); 316 zcore_reipl_file = debugfs_create_file("reipl", S_IRUSR, zcore_dir, 317 NULL, &zcore_reipl_fops); 318 zcore_hsa_file = debugfs_create_file("hsa", S_IRUSR|S_IWUSR, zcore_dir, 319 NULL, &zcore_hsa_fops); 320 321 register_reboot_notifier(&zcore_reboot_notifier); 322 atomic_notifier_chain_register(&panic_notifier_list, &zcore_on_panic_notifier); 323 324 return 0; 325 fail: 326 diag308(DIAG308_REL_HSA, NULL); 327 return rc; 328 } 329 subsys_initcall(zcore_init); 330