1 /* 2 * RAM Oops/Panic logger 3 * 4 * Copyright (C) 2010 Marco Stornelli <marco.stornelli@gmail.com> 5 * Copyright (C) 2011 Kees Cook <keescook@chromium.org> 6 * 7 * This program is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU General Public License 9 * version 2 as published by the Free Software Foundation. 10 * 11 * This program is distributed in the hope that it will be useful, but 12 * WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14 * General Public License for more details. 15 * 16 * You should have received a copy of the GNU General Public License 17 * along with this program; if not, write to the Free Software 18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 19 * 02110-1301 USA 20 * 21 */ 22 23 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 24 25 #include <linux/kernel.h> 26 #include <linux/err.h> 27 #include <linux/module.h> 28 #include <linux/pstore.h> 29 #include <linux/time.h> 30 #include <linux/io.h> 31 #include <linux/ioport.h> 32 #include <linux/platform_device.h> 33 #include <linux/slab.h> 34 #include <linux/pstore_ram.h> 35 36 #define RAMOOPS_KERNMSG_HDR "====" 37 #define MIN_MEM_SIZE 4096UL 38 39 static ulong record_size = MIN_MEM_SIZE; 40 module_param(record_size, ulong, 0400); 41 MODULE_PARM_DESC(record_size, 42 "size of each dump done on oops/panic"); 43 44 static ulong mem_address; 45 module_param(mem_address, ulong, 0400); 46 MODULE_PARM_DESC(mem_address, 47 "start of reserved RAM used to store oops/panic logs"); 48 49 static ulong mem_size; 50 module_param(mem_size, ulong, 0400); 51 MODULE_PARM_DESC(mem_size, 52 "size of reserved RAM used to store oops/panic logs"); 53 54 static int dump_oops = 1; 55 module_param(dump_oops, int, 0600); 56 MODULE_PARM_DESC(dump_oops, 57 "set to 1 to dump oopses, 0 to only dump panics (default 1)"); 58 59 static int ramoops_ecc; 60 module_param_named(ecc, ramoops_ecc, int, 0600); 61 MODULE_PARM_DESC(ramoops_ecc, 62 "set to 1 to enable ECC support"); 63 64 struct ramoops_context { 65 struct persistent_ram_zone **przs; 66 phys_addr_t phys_addr; 67 unsigned long size; 68 size_t record_size; 69 int dump_oops; 70 bool ecc; 71 unsigned int count; 72 unsigned int max_count; 73 unsigned int read_count; 74 struct pstore_info pstore; 75 }; 76 77 static struct platform_device *dummy; 78 static struct ramoops_platform_data *dummy_data; 79 80 static int ramoops_pstore_open(struct pstore_info *psi) 81 { 82 struct ramoops_context *cxt = psi->data; 83 84 cxt->read_count = 0; 85 return 0; 86 } 87 88 static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type, 89 struct timespec *time, 90 char **buf, 91 struct pstore_info *psi) 92 { 93 ssize_t size; 94 struct ramoops_context *cxt = psi->data; 95 struct persistent_ram_zone *prz; 96 97 if (cxt->read_count >= cxt->max_count) 98 return -EINVAL; 99 100 *id = cxt->read_count++; 101 prz = cxt->przs[*id]; 102 103 /* Only supports dmesg output so far. */ 104 *type = PSTORE_TYPE_DMESG; 105 /* TODO(kees): Bogus time for the moment. */ 106 time->tv_sec = 0; 107 time->tv_nsec = 0; 108 109 /* Update old/shadowed buffer. */ 110 persistent_ram_save_old(prz); 111 size = persistent_ram_old_size(prz); 112 *buf = kmalloc(size, GFP_KERNEL); 113 if (*buf == NULL) 114 return -ENOMEM; 115 memcpy(*buf, persistent_ram_old(prz), size); 116 117 return size; 118 } 119 120 static size_t ramoops_write_kmsg_hdr(struct persistent_ram_zone *prz) 121 { 122 char *hdr; 123 struct timeval timestamp; 124 size_t len; 125 126 do_gettimeofday(×tamp); 127 hdr = kasprintf(GFP_ATOMIC, RAMOOPS_KERNMSG_HDR "%lu.%lu\n", 128 (long)timestamp.tv_sec, (long)timestamp.tv_usec); 129 WARN_ON_ONCE(!hdr); 130 len = hdr ? strlen(hdr) : 0; 131 persistent_ram_write(prz, hdr, len); 132 kfree(hdr); 133 134 return len; 135 } 136 137 static int ramoops_pstore_write(enum pstore_type_id type, 138 enum kmsg_dump_reason reason, 139 u64 *id, 140 unsigned int part, 141 size_t size, struct pstore_info *psi) 142 { 143 struct ramoops_context *cxt = psi->data; 144 struct persistent_ram_zone *prz = cxt->przs[cxt->count]; 145 size_t hlen; 146 147 /* Currently ramoops is designed to only store dmesg dumps. */ 148 if (type != PSTORE_TYPE_DMESG) 149 return -EINVAL; 150 151 /* Out of the various dmesg dump types, ramoops is currently designed 152 * to only store crash logs, rather than storing general kernel logs. 153 */ 154 if (reason != KMSG_DUMP_OOPS && 155 reason != KMSG_DUMP_PANIC) 156 return -EINVAL; 157 158 /* Skip Oopes when configured to do so. */ 159 if (reason == KMSG_DUMP_OOPS && !cxt->dump_oops) 160 return -EINVAL; 161 162 /* Explicitly only take the first part of any new crash. 163 * If our buffer is larger than kmsg_bytes, this can never happen, 164 * and if our buffer is smaller than kmsg_bytes, we don't want the 165 * report split across multiple records. 166 */ 167 if (part != 1) 168 return -ENOSPC; 169 170 hlen = ramoops_write_kmsg_hdr(prz); 171 if (size + hlen > prz->buffer_size) 172 size = prz->buffer_size - hlen; 173 persistent_ram_write(prz, cxt->pstore.buf, size); 174 175 cxt->count = (cxt->count + 1) % cxt->max_count; 176 177 return 0; 178 } 179 180 static int ramoops_pstore_erase(enum pstore_type_id type, u64 id, 181 struct pstore_info *psi) 182 { 183 struct ramoops_context *cxt = psi->data; 184 185 if (id >= cxt->max_count) 186 return -EINVAL; 187 188 persistent_ram_free_old(cxt->przs[id]); 189 persistent_ram_zap(cxt->przs[id]); 190 191 return 0; 192 } 193 194 static struct ramoops_context oops_cxt = { 195 .pstore = { 196 .owner = THIS_MODULE, 197 .name = "ramoops", 198 .open = ramoops_pstore_open, 199 .read = ramoops_pstore_read, 200 .write = ramoops_pstore_write, 201 .erase = ramoops_pstore_erase, 202 }, 203 }; 204 205 static int __init ramoops_probe(struct platform_device *pdev) 206 { 207 struct device *dev = &pdev->dev; 208 struct ramoops_platform_data *pdata = pdev->dev.platform_data; 209 struct ramoops_context *cxt = &oops_cxt; 210 int err = -EINVAL; 211 int i; 212 213 /* Only a single ramoops area allowed at a time, so fail extra 214 * probes. 215 */ 216 if (cxt->max_count) 217 goto fail_out; 218 219 if (!pdata->mem_size || !pdata->record_size) { 220 pr_err("The memory size and the record size must be " 221 "non-zero\n"); 222 goto fail_out; 223 } 224 225 pdata->mem_size = rounddown_pow_of_two(pdata->mem_size); 226 pdata->record_size = rounddown_pow_of_two(pdata->record_size); 227 228 /* Check for the minimum memory size */ 229 if (pdata->mem_size < MIN_MEM_SIZE && 230 pdata->record_size < MIN_MEM_SIZE) { 231 pr_err("memory size too small, minimum is %lu\n", 232 MIN_MEM_SIZE); 233 goto fail_out; 234 } 235 236 if (pdata->mem_size < pdata->record_size) { 237 pr_err("The memory size must be larger than the " 238 "records size\n"); 239 goto fail_out; 240 } 241 242 cxt->max_count = pdata->mem_size / pdata->record_size; 243 cxt->count = 0; 244 cxt->size = pdata->mem_size; 245 cxt->phys_addr = pdata->mem_address; 246 cxt->record_size = pdata->record_size; 247 cxt->dump_oops = pdata->dump_oops; 248 cxt->ecc = pdata->ecc; 249 250 cxt->przs = kzalloc(sizeof(*cxt->przs) * cxt->max_count, GFP_KERNEL); 251 if (!cxt->przs) { 252 err = -ENOMEM; 253 dev_err(dev, "failed to initialize a prz array\n"); 254 goto fail_out; 255 } 256 257 for (i = 0; i < cxt->max_count; i++) { 258 size_t sz = cxt->record_size; 259 phys_addr_t start = cxt->phys_addr + sz * i; 260 261 cxt->przs[i] = persistent_ram_new(start, sz, cxt->ecc); 262 if (IS_ERR(cxt->przs[i])) { 263 err = PTR_ERR(cxt->przs[i]); 264 dev_err(dev, "failed to request mem region (0x%zx@0x%llx): %d\n", 265 sz, (unsigned long long)start, err); 266 goto fail_przs; 267 } 268 } 269 270 cxt->pstore.data = cxt; 271 cxt->pstore.bufsize = cxt->przs[0]->buffer_size; 272 cxt->pstore.buf = kmalloc(cxt->pstore.bufsize, GFP_KERNEL); 273 spin_lock_init(&cxt->pstore.buf_lock); 274 if (!cxt->pstore.buf) { 275 pr_err("cannot allocate pstore buffer\n"); 276 goto fail_clear; 277 } 278 279 err = pstore_register(&cxt->pstore); 280 if (err) { 281 pr_err("registering with pstore failed\n"); 282 goto fail_buf; 283 } 284 285 /* 286 * Update the module parameter variables as well so they are visible 287 * through /sys/module/ramoops/parameters/ 288 */ 289 mem_size = pdata->mem_size; 290 mem_address = pdata->mem_address; 291 record_size = pdata->record_size; 292 dump_oops = pdata->dump_oops; 293 294 pr_info("attached 0x%lx@0x%llx (%ux0x%zx), ecc: %s\n", 295 cxt->size, (unsigned long long)cxt->phys_addr, 296 cxt->max_count, cxt->record_size, 297 ramoops_ecc ? "on" : "off"); 298 299 return 0; 300 301 fail_buf: 302 kfree(cxt->pstore.buf); 303 fail_clear: 304 cxt->pstore.bufsize = 0; 305 cxt->max_count = 0; 306 fail_przs: 307 for (i = 0; cxt->przs[i]; i++) 308 persistent_ram_free(cxt->przs[i]); 309 kfree(cxt->przs); 310 fail_out: 311 return err; 312 } 313 314 static int __exit ramoops_remove(struct platform_device *pdev) 315 { 316 #if 0 317 /* TODO(kees): We cannot unload ramoops since pstore doesn't support 318 * unregistering yet. 319 */ 320 struct ramoops_context *cxt = &oops_cxt; 321 322 iounmap(cxt->virt_addr); 323 release_mem_region(cxt->phys_addr, cxt->size); 324 cxt->max_count = 0; 325 326 /* TODO(kees): When pstore supports unregistering, call it here. */ 327 kfree(cxt->pstore.buf); 328 cxt->pstore.bufsize = 0; 329 330 return 0; 331 #endif 332 return -EBUSY; 333 } 334 335 static struct platform_driver ramoops_driver = { 336 .remove = __exit_p(ramoops_remove), 337 .driver = { 338 .name = "ramoops", 339 .owner = THIS_MODULE, 340 }, 341 }; 342 343 static int __init ramoops_init(void) 344 { 345 int ret; 346 ret = platform_driver_probe(&ramoops_driver, ramoops_probe); 347 if (ret == -ENODEV) { 348 /* 349 * If we didn't find a platform device, we use module parameters 350 * building platform data on the fly. 351 */ 352 pr_info("platform device not found, using module parameters\n"); 353 dummy_data = kzalloc(sizeof(struct ramoops_platform_data), 354 GFP_KERNEL); 355 if (!dummy_data) 356 return -ENOMEM; 357 dummy_data->mem_size = mem_size; 358 dummy_data->mem_address = mem_address; 359 dummy_data->record_size = record_size; 360 dummy_data->dump_oops = dump_oops; 361 dummy_data->ecc = ramoops_ecc; 362 dummy = platform_create_bundle(&ramoops_driver, ramoops_probe, 363 NULL, 0, dummy_data, 364 sizeof(struct ramoops_platform_data)); 365 366 if (IS_ERR(dummy)) 367 ret = PTR_ERR(dummy); 368 else 369 ret = 0; 370 } 371 372 return ret; 373 } 374 375 static void __exit ramoops_exit(void) 376 { 377 platform_driver_unregister(&ramoops_driver); 378 kfree(dummy_data); 379 } 380 381 module_init(ramoops_init); 382 module_exit(ramoops_exit); 383 384 MODULE_LICENSE("GPL"); 385 MODULE_AUTHOR("Marco Stornelli <marco.stornelli@gmail.com>"); 386 MODULE_DESCRIPTION("RAM Oops/Panic logger/driver"); 387