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/reboot.h> 19 20 #include <asm/asm-offsets.h> 21 #include <asm/ipl.h> 22 #include <asm/sclp.h> 23 #include <asm/setup.h> 24 #include <linux/uaccess.h> 25 #include <asm/debug.h> 26 #include <asm/processor.h> 27 #include <asm/irqflags.h> 28 #include <asm/checksum.h> 29 #include <asm/os_info.h> 30 #include <asm/switch_to.h> 31 #include "sclp.h" 32 33 #define TRACE(x...) debug_sprintf_event(zcore_dbf, 1, x) 34 35 enum arch_id { 36 ARCH_S390 = 0, 37 ARCH_S390X = 1, 38 }; 39 40 struct ipib_info { 41 unsigned long ipib; 42 u32 checksum; 43 } __attribute__((packed)); 44 45 static struct debug_info *zcore_dbf; 46 static int hsa_available; 47 static struct dentry *zcore_dir; 48 static struct dentry *zcore_reipl_file; 49 static struct dentry *zcore_hsa_file; 50 static struct ipl_parameter_block *zcore_ipl_block; 51 52 static char hsa_buf[PAGE_SIZE] __aligned(PAGE_SIZE); 53 54 /* 55 * Copy memory from HSA to user memory (not reentrant): 56 * 57 * @dest: User buffer where memory should be copied to 58 * @src: Start address within HSA where data should be copied 59 * @count: Size of buffer, which should be copied 60 */ 61 int memcpy_hsa_user(void __user *dest, unsigned long src, size_t count) 62 { 63 unsigned long offset, bytes; 64 65 if (!hsa_available) 66 return -ENODATA; 67 68 while (count) { 69 if (sclp_sdias_copy(hsa_buf, src / PAGE_SIZE + 2, 1)) { 70 TRACE("sclp_sdias_copy() failed\n"); 71 return -EIO; 72 } 73 offset = src % PAGE_SIZE; 74 bytes = min(PAGE_SIZE - offset, count); 75 if (copy_to_user(dest, hsa_buf + offset, bytes)) 76 return -EFAULT; 77 src += bytes; 78 dest += bytes; 79 count -= bytes; 80 } 81 return 0; 82 } 83 84 /* 85 * Copy memory from HSA to kernel memory (not reentrant): 86 * 87 * @dest: Kernel or user buffer where memory should be copied to 88 * @src: Start address within HSA where data should be copied 89 * @count: Size of buffer, which should be copied 90 */ 91 int memcpy_hsa_kernel(void *dest, unsigned long src, size_t count) 92 { 93 unsigned long offset, bytes; 94 95 if (!hsa_available) 96 return -ENODATA; 97 98 while (count) { 99 if (sclp_sdias_copy(hsa_buf, src / PAGE_SIZE + 2, 1)) { 100 TRACE("sclp_sdias_copy() failed\n"); 101 return -EIO; 102 } 103 offset = src % PAGE_SIZE; 104 bytes = min(PAGE_SIZE - offset, count); 105 memcpy(dest, hsa_buf + offset, bytes); 106 src += bytes; 107 dest += bytes; 108 count -= bytes; 109 } 110 return 0; 111 } 112 113 static int __init init_cpu_info(void) 114 { 115 struct save_area *sa; 116 117 /* get info for boot cpu from lowcore, stored in the HSA */ 118 sa = save_area_boot_cpu(); 119 if (!sa) 120 return -ENOMEM; 121 if (memcpy_hsa_kernel(hsa_buf, __LC_FPREGS_SAVE_AREA, 512) < 0) { 122 TRACE("could not copy from HSA\n"); 123 return -EIO; 124 } 125 save_area_add_regs(sa, hsa_buf); /* vx registers are saved in smp.c */ 126 return 0; 127 } 128 129 /* 130 * Release the HSA 131 */ 132 static void release_hsa(void) 133 { 134 diag308(DIAG308_REL_HSA, NULL); 135 hsa_available = 0; 136 } 137 138 static ssize_t zcore_reipl_write(struct file *filp, const char __user *buf, 139 size_t count, loff_t *ppos) 140 { 141 if (zcore_ipl_block) { 142 diag308(DIAG308_SET, zcore_ipl_block); 143 diag308(DIAG308_LOAD_CLEAR, NULL); 144 } 145 return count; 146 } 147 148 static int zcore_reipl_open(struct inode *inode, struct file *filp) 149 { 150 return stream_open(inode, filp); 151 } 152 153 static int zcore_reipl_release(struct inode *inode, struct file *filp) 154 { 155 return 0; 156 } 157 158 static const struct file_operations zcore_reipl_fops = { 159 .owner = THIS_MODULE, 160 .write = zcore_reipl_write, 161 .open = zcore_reipl_open, 162 .release = zcore_reipl_release, 163 .llseek = no_llseek, 164 }; 165 166 static ssize_t zcore_hsa_read(struct file *filp, char __user *buf, 167 size_t count, loff_t *ppos) 168 { 169 static char str[18]; 170 171 if (hsa_available) 172 snprintf(str, sizeof(str), "%lx\n", sclp.hsa_size); 173 else 174 snprintf(str, sizeof(str), "0\n"); 175 return simple_read_from_buffer(buf, count, ppos, str, strlen(str)); 176 } 177 178 static ssize_t zcore_hsa_write(struct file *filp, const char __user *buf, 179 size_t count, loff_t *ppos) 180 { 181 char value; 182 183 if (*ppos != 0) 184 return -EPIPE; 185 if (copy_from_user(&value, buf, 1)) 186 return -EFAULT; 187 if (value != '0') 188 return -EINVAL; 189 release_hsa(); 190 return count; 191 } 192 193 static const struct file_operations zcore_hsa_fops = { 194 .owner = THIS_MODULE, 195 .write = zcore_hsa_write, 196 .read = zcore_hsa_read, 197 .open = nonseekable_open, 198 .llseek = no_llseek, 199 }; 200 201 static int __init check_sdias(void) 202 { 203 if (!sclp.hsa_size) { 204 TRACE("Could not determine HSA size\n"); 205 return -ENODEV; 206 } 207 return 0; 208 } 209 210 /* 211 * Provide IPL parameter information block from either HSA or memory 212 * for future reipl 213 */ 214 static int __init zcore_reipl_init(void) 215 { 216 struct ipib_info ipib_info; 217 int rc; 218 219 rc = memcpy_hsa_kernel(&ipib_info, __LC_DUMP_REIPL, sizeof(ipib_info)); 220 if (rc) 221 return rc; 222 if (ipib_info.ipib == 0) 223 return 0; 224 zcore_ipl_block = (void *) __get_free_page(GFP_KERNEL); 225 if (!zcore_ipl_block) 226 return -ENOMEM; 227 if (ipib_info.ipib < sclp.hsa_size) 228 rc = memcpy_hsa_kernel(zcore_ipl_block, ipib_info.ipib, 229 PAGE_SIZE); 230 else 231 rc = memcpy_real(zcore_ipl_block, (void *) ipib_info.ipib, 232 PAGE_SIZE); 233 if (rc || (__force u32)csum_partial(zcore_ipl_block, zcore_ipl_block->hdr.len, 0) != 234 ipib_info.checksum) { 235 TRACE("Checksum does not match\n"); 236 free_page((unsigned long) zcore_ipl_block); 237 zcore_ipl_block = NULL; 238 } 239 return 0; 240 } 241 242 static int zcore_reboot_and_on_panic_handler(struct notifier_block *self, 243 unsigned long event, 244 void *data) 245 { 246 if (hsa_available) 247 release_hsa(); 248 249 return NOTIFY_OK; 250 } 251 252 static struct notifier_block zcore_reboot_notifier = { 253 .notifier_call = zcore_reboot_and_on_panic_handler, 254 /* we need to be notified before reipl and kdump */ 255 .priority = INT_MAX, 256 }; 257 258 static struct notifier_block zcore_on_panic_notifier = { 259 .notifier_call = zcore_reboot_and_on_panic_handler, 260 /* we need to be notified before reipl and kdump */ 261 .priority = INT_MAX, 262 }; 263 264 static int __init zcore_init(void) 265 { 266 unsigned char arch; 267 int rc; 268 269 if (!is_ipl_type_dump()) 270 return -ENODATA; 271 if (OLDMEM_BASE) 272 return -ENODATA; 273 274 zcore_dbf = debug_register("zcore", 4, 1, 4 * sizeof(long)); 275 debug_register_view(zcore_dbf, &debug_sprintf_view); 276 debug_set_level(zcore_dbf, 6); 277 278 if (ipl_info.type == IPL_TYPE_FCP_DUMP) { 279 TRACE("type: fcp\n"); 280 TRACE("devno: %x\n", ipl_info.data.fcp.dev_id.devno); 281 TRACE("wwpn: %llx\n", (unsigned long long) ipl_info.data.fcp.wwpn); 282 TRACE("lun: %llx\n", (unsigned long long) ipl_info.data.fcp.lun); 283 } else if (ipl_info.type == IPL_TYPE_NVME_DUMP) { 284 TRACE("type: nvme\n"); 285 TRACE("fid: %x\n", ipl_info.data.nvme.fid); 286 TRACE("nsid: %x\n", ipl_info.data.nvme.nsid); 287 } 288 289 rc = sclp_sdias_init(); 290 if (rc) 291 goto fail; 292 293 rc = check_sdias(); 294 if (rc) 295 goto fail; 296 hsa_available = 1; 297 298 rc = memcpy_hsa_kernel(&arch, __LC_AR_MODE_ID, 1); 299 if (rc) 300 goto fail; 301 302 if (arch == ARCH_S390) { 303 pr_alert("The 64-bit dump tool cannot be used for a " 304 "32-bit system\n"); 305 rc = -EINVAL; 306 goto fail; 307 } 308 309 pr_alert("The dump process started for a 64-bit operating system\n"); 310 rc = init_cpu_info(); 311 if (rc) 312 goto fail; 313 314 rc = zcore_reipl_init(); 315 if (rc) 316 goto fail; 317 318 zcore_dir = debugfs_create_dir("zcore" , NULL); 319 zcore_reipl_file = debugfs_create_file("reipl", S_IRUSR, zcore_dir, 320 NULL, &zcore_reipl_fops); 321 zcore_hsa_file = debugfs_create_file("hsa", S_IRUSR|S_IWUSR, zcore_dir, 322 NULL, &zcore_hsa_fops); 323 324 register_reboot_notifier(&zcore_reboot_notifier); 325 atomic_notifier_chain_register(&panic_notifier_list, &zcore_on_panic_notifier); 326 327 return 0; 328 fail: 329 diag308(DIAG308_REL_HSA, NULL); 330 return rc; 331 } 332 subsys_initcall(zcore_init); 333