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_data.start) 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); 334