1 /* 2 * Copyright 2010 Google Inc. All Rights Reserved. 3 * Author: dlaurie@google.com (Duncan Laurie) 4 * 5 * Re-worked to expose sysfs APIs by mikew@google.com (Mike Waychison) 6 * 7 * EFI SMI interface for Google platforms 8 */ 9 10 #include <linux/kernel.h> 11 #include <linux/init.h> 12 #include <linux/types.h> 13 #include <linux/device.h> 14 #include <linux/platform_device.h> 15 #include <linux/errno.h> 16 #include <linux/string.h> 17 #include <linux/spinlock.h> 18 #include <linux/dma-mapping.h> 19 #include <linux/dmapool.h> 20 #include <linux/fs.h> 21 #include <linux/slab.h> 22 #include <linux/ioctl.h> 23 #include <linux/acpi.h> 24 #include <linux/io.h> 25 #include <linux/uaccess.h> 26 #include <linux/dmi.h> 27 #include <linux/kdebug.h> 28 #include <linux/reboot.h> 29 #include <linux/efi.h> 30 #include <linux/module.h> 31 #include <linux/ucs2_string.h> 32 33 #define GSMI_SHUTDOWN_CLEAN 0 /* Clean Shutdown */ 34 /* TODO(mikew@google.com): Tie in HARDLOCKUP_DETECTOR with NMIWDT */ 35 #define GSMI_SHUTDOWN_NMIWDT 1 /* NMI Watchdog */ 36 #define GSMI_SHUTDOWN_PANIC 2 /* Panic */ 37 #define GSMI_SHUTDOWN_OOPS 3 /* Oops */ 38 #define GSMI_SHUTDOWN_DIE 4 /* Die -- No longer meaningful */ 39 #define GSMI_SHUTDOWN_MCE 5 /* Machine Check */ 40 #define GSMI_SHUTDOWN_SOFTWDT 6 /* Software Watchdog */ 41 #define GSMI_SHUTDOWN_MBE 7 /* Uncorrected ECC */ 42 #define GSMI_SHUTDOWN_TRIPLE 8 /* Triple Fault */ 43 44 #define DRIVER_VERSION "1.0" 45 #define GSMI_GUID_SIZE 16 46 #define GSMI_BUF_SIZE 1024 47 #define GSMI_BUF_ALIGN sizeof(u64) 48 #define GSMI_CALLBACK 0xef 49 50 /* SMI return codes */ 51 #define GSMI_SUCCESS 0x00 52 #define GSMI_UNSUPPORTED2 0x03 53 #define GSMI_LOG_FULL 0x0b 54 #define GSMI_VAR_NOT_FOUND 0x0e 55 #define GSMI_HANDSHAKE_SPIN 0x7d 56 #define GSMI_HANDSHAKE_CF 0x7e 57 #define GSMI_HANDSHAKE_NONE 0x7f 58 #define GSMI_INVALID_PARAMETER 0x82 59 #define GSMI_UNSUPPORTED 0x83 60 #define GSMI_BUFFER_TOO_SMALL 0x85 61 #define GSMI_NOT_READY 0x86 62 #define GSMI_DEVICE_ERROR 0x87 63 #define GSMI_NOT_FOUND 0x8e 64 65 #define QUIRKY_BOARD_HASH 0x78a30a50 66 67 /* Internally used commands passed to the firmware */ 68 #define GSMI_CMD_GET_NVRAM_VAR 0x01 69 #define GSMI_CMD_GET_NEXT_VAR 0x02 70 #define GSMI_CMD_SET_NVRAM_VAR 0x03 71 #define GSMI_CMD_SET_EVENT_LOG 0x08 72 #define GSMI_CMD_CLEAR_EVENT_LOG 0x09 73 #define GSMI_CMD_CLEAR_CONFIG 0x20 74 #define GSMI_CMD_HANDSHAKE_TYPE 0xC1 75 76 /* Magic entry type for kernel events */ 77 #define GSMI_LOG_ENTRY_TYPE_KERNEL 0xDEAD 78 79 /* SMI buffers must be in 32bit physical address space */ 80 struct gsmi_buf { 81 u8 *start; /* start of buffer */ 82 size_t length; /* length of buffer */ 83 dma_addr_t handle; /* dma allocation handle */ 84 u32 address; /* physical address of buffer */ 85 }; 86 87 struct gsmi_device { 88 struct platform_device *pdev; /* platform device */ 89 struct gsmi_buf *name_buf; /* variable name buffer */ 90 struct gsmi_buf *data_buf; /* generic data buffer */ 91 struct gsmi_buf *param_buf; /* parameter buffer */ 92 spinlock_t lock; /* serialize access to SMIs */ 93 u16 smi_cmd; /* SMI command port */ 94 int handshake_type; /* firmware handler interlock type */ 95 struct dma_pool *dma_pool; /* DMA buffer pool */ 96 } gsmi_dev; 97 98 /* Packed structures for communicating with the firmware */ 99 struct gsmi_nvram_var_param { 100 efi_guid_t guid; 101 u32 name_ptr; 102 u32 attributes; 103 u32 data_len; 104 u32 data_ptr; 105 } __packed; 106 107 struct gsmi_get_next_var_param { 108 u8 guid[GSMI_GUID_SIZE]; 109 u32 name_ptr; 110 u32 name_len; 111 } __packed; 112 113 struct gsmi_set_eventlog_param { 114 u32 data_ptr; 115 u32 data_len; 116 u32 type; 117 } __packed; 118 119 /* Event log formats */ 120 struct gsmi_log_entry_type_1 { 121 u16 type; 122 u32 instance; 123 } __packed; 124 125 126 /* 127 * Some platforms don't have explicit SMI handshake 128 * and need to wait for SMI to complete. 129 */ 130 #define GSMI_DEFAULT_SPINCOUNT 0x10000 131 static unsigned int spincount = GSMI_DEFAULT_SPINCOUNT; 132 module_param(spincount, uint, 0600); 133 MODULE_PARM_DESC(spincount, 134 "The number of loop iterations to use when using the spin handshake."); 135 136 static struct gsmi_buf *gsmi_buf_alloc(void) 137 { 138 struct gsmi_buf *smibuf; 139 140 smibuf = kzalloc(sizeof(*smibuf), GFP_KERNEL); 141 if (!smibuf) { 142 printk(KERN_ERR "gsmi: out of memory\n"); 143 return NULL; 144 } 145 146 /* allocate buffer in 32bit address space */ 147 smibuf->start = dma_pool_alloc(gsmi_dev.dma_pool, GFP_KERNEL, 148 &smibuf->handle); 149 if (!smibuf->start) { 150 printk(KERN_ERR "gsmi: failed to allocate name buffer\n"); 151 kfree(smibuf); 152 return NULL; 153 } 154 155 /* fill in the buffer handle */ 156 smibuf->length = GSMI_BUF_SIZE; 157 smibuf->address = (u32)virt_to_phys(smibuf->start); 158 159 return smibuf; 160 } 161 162 static void gsmi_buf_free(struct gsmi_buf *smibuf) 163 { 164 if (smibuf) { 165 if (smibuf->start) 166 dma_pool_free(gsmi_dev.dma_pool, smibuf->start, 167 smibuf->handle); 168 kfree(smibuf); 169 } 170 } 171 172 /* 173 * Make a call to gsmi func(sub). GSMI error codes are translated to 174 * in-kernel errnos (0 on success, -ERRNO on error). 175 */ 176 static int gsmi_exec(u8 func, u8 sub) 177 { 178 u16 cmd = (sub << 8) | func; 179 u16 result = 0; 180 int rc = 0; 181 182 /* 183 * AH : Subfunction number 184 * AL : Function number 185 * EBX : Parameter block address 186 * DX : SMI command port 187 * 188 * Three protocols here. See also the comment in gsmi_init(). 189 */ 190 if (gsmi_dev.handshake_type == GSMI_HANDSHAKE_CF) { 191 /* 192 * If handshake_type == HANDSHAKE_CF then set CF on the 193 * way in and wait for the handler to clear it; this avoids 194 * corrupting register state on those chipsets which have 195 * a delay between writing the SMI trigger register and 196 * entering SMM. 197 */ 198 asm volatile ( 199 "stc\n" 200 "outb %%al, %%dx\n" 201 "1: jc 1b\n" 202 : "=a" (result) 203 : "0" (cmd), 204 "d" (gsmi_dev.smi_cmd), 205 "b" (gsmi_dev.param_buf->address) 206 : "memory", "cc" 207 ); 208 } else if (gsmi_dev.handshake_type == GSMI_HANDSHAKE_SPIN) { 209 /* 210 * If handshake_type == HANDSHAKE_SPIN we spin a 211 * hundred-ish usecs to ensure the SMI has triggered. 212 */ 213 asm volatile ( 214 "outb %%al, %%dx\n" 215 "1: loop 1b\n" 216 : "=a" (result) 217 : "0" (cmd), 218 "d" (gsmi_dev.smi_cmd), 219 "b" (gsmi_dev.param_buf->address), 220 "c" (spincount) 221 : "memory", "cc" 222 ); 223 } else { 224 /* 225 * If handshake_type == HANDSHAKE_NONE we do nothing; 226 * either we don't need to or it's legacy firmware that 227 * doesn't understand the CF protocol. 228 */ 229 asm volatile ( 230 "outb %%al, %%dx\n\t" 231 : "=a" (result) 232 : "0" (cmd), 233 "d" (gsmi_dev.smi_cmd), 234 "b" (gsmi_dev.param_buf->address) 235 : "memory", "cc" 236 ); 237 } 238 239 /* check return code from SMI handler */ 240 switch (result) { 241 case GSMI_SUCCESS: 242 break; 243 case GSMI_VAR_NOT_FOUND: 244 /* not really an error, but let the caller know */ 245 rc = 1; 246 break; 247 case GSMI_INVALID_PARAMETER: 248 printk(KERN_ERR "gsmi: exec 0x%04x: Invalid parameter\n", cmd); 249 rc = -EINVAL; 250 break; 251 case GSMI_BUFFER_TOO_SMALL: 252 printk(KERN_ERR "gsmi: exec 0x%04x: Buffer too small\n", cmd); 253 rc = -ENOMEM; 254 break; 255 case GSMI_UNSUPPORTED: 256 case GSMI_UNSUPPORTED2: 257 if (sub != GSMI_CMD_HANDSHAKE_TYPE) 258 printk(KERN_ERR "gsmi: exec 0x%04x: Not supported\n", 259 cmd); 260 rc = -ENOSYS; 261 break; 262 case GSMI_NOT_READY: 263 printk(KERN_ERR "gsmi: exec 0x%04x: Not ready\n", cmd); 264 rc = -EBUSY; 265 break; 266 case GSMI_DEVICE_ERROR: 267 printk(KERN_ERR "gsmi: exec 0x%04x: Device error\n", cmd); 268 rc = -EFAULT; 269 break; 270 case GSMI_NOT_FOUND: 271 printk(KERN_ERR "gsmi: exec 0x%04x: Data not found\n", cmd); 272 rc = -ENOENT; 273 break; 274 case GSMI_LOG_FULL: 275 printk(KERN_ERR "gsmi: exec 0x%04x: Log full\n", cmd); 276 rc = -ENOSPC; 277 break; 278 case GSMI_HANDSHAKE_CF: 279 case GSMI_HANDSHAKE_SPIN: 280 case GSMI_HANDSHAKE_NONE: 281 rc = result; 282 break; 283 default: 284 printk(KERN_ERR "gsmi: exec 0x%04x: Unknown error 0x%04x\n", 285 cmd, result); 286 rc = -ENXIO; 287 } 288 289 return rc; 290 } 291 292 static efi_status_t gsmi_get_variable(efi_char16_t *name, 293 efi_guid_t *vendor, u32 *attr, 294 unsigned long *data_size, 295 void *data) 296 { 297 struct gsmi_nvram_var_param param = { 298 .name_ptr = gsmi_dev.name_buf->address, 299 .data_ptr = gsmi_dev.data_buf->address, 300 .data_len = (u32)*data_size, 301 }; 302 efi_status_t ret = EFI_SUCCESS; 303 unsigned long flags; 304 size_t name_len = ucs2_strnlen(name, GSMI_BUF_SIZE / 2); 305 int rc; 306 307 if (name_len >= GSMI_BUF_SIZE / 2) 308 return EFI_BAD_BUFFER_SIZE; 309 310 spin_lock_irqsave(&gsmi_dev.lock, flags); 311 312 /* Vendor guid */ 313 memcpy(¶m.guid, vendor, sizeof(param.guid)); 314 315 /* variable name, already in UTF-16 */ 316 memset(gsmi_dev.name_buf->start, 0, gsmi_dev.name_buf->length); 317 memcpy(gsmi_dev.name_buf->start, name, name_len * 2); 318 319 /* data pointer */ 320 memset(gsmi_dev.data_buf->start, 0, gsmi_dev.data_buf->length); 321 322 /* parameter buffer */ 323 memset(gsmi_dev.param_buf->start, 0, gsmi_dev.param_buf->length); 324 memcpy(gsmi_dev.param_buf->start, ¶m, sizeof(param)); 325 326 rc = gsmi_exec(GSMI_CALLBACK, GSMI_CMD_GET_NVRAM_VAR); 327 if (rc < 0) { 328 printk(KERN_ERR "gsmi: Get Variable failed\n"); 329 ret = EFI_LOAD_ERROR; 330 } else if (rc == 1) { 331 /* variable was not found */ 332 ret = EFI_NOT_FOUND; 333 } else { 334 /* Get the arguments back */ 335 memcpy(¶m, gsmi_dev.param_buf->start, sizeof(param)); 336 337 /* The size reported is the min of all of our buffers */ 338 *data_size = min_t(unsigned long, *data_size, 339 gsmi_dev.data_buf->length); 340 *data_size = min_t(unsigned long, *data_size, param.data_len); 341 342 /* Copy data back to return buffer. */ 343 memcpy(data, gsmi_dev.data_buf->start, *data_size); 344 345 /* All variables are have the following attributes */ 346 *attr = EFI_VARIABLE_NON_VOLATILE | 347 EFI_VARIABLE_BOOTSERVICE_ACCESS | 348 EFI_VARIABLE_RUNTIME_ACCESS; 349 } 350 351 spin_unlock_irqrestore(&gsmi_dev.lock, flags); 352 353 return ret; 354 } 355 356 static efi_status_t gsmi_get_next_variable(unsigned long *name_size, 357 efi_char16_t *name, 358 efi_guid_t *vendor) 359 { 360 struct gsmi_get_next_var_param param = { 361 .name_ptr = gsmi_dev.name_buf->address, 362 .name_len = gsmi_dev.name_buf->length, 363 }; 364 efi_status_t ret = EFI_SUCCESS; 365 int rc; 366 unsigned long flags; 367 368 /* For the moment, only support buffers that exactly match in size */ 369 if (*name_size != GSMI_BUF_SIZE) 370 return EFI_BAD_BUFFER_SIZE; 371 372 /* Let's make sure the thing is at least null-terminated */ 373 if (ucs2_strnlen(name, GSMI_BUF_SIZE / 2) == GSMI_BUF_SIZE / 2) 374 return EFI_INVALID_PARAMETER; 375 376 spin_lock_irqsave(&gsmi_dev.lock, flags); 377 378 /* guid */ 379 memcpy(¶m.guid, vendor, sizeof(param.guid)); 380 381 /* variable name, already in UTF-16 */ 382 memcpy(gsmi_dev.name_buf->start, name, *name_size); 383 384 /* parameter buffer */ 385 memset(gsmi_dev.param_buf->start, 0, gsmi_dev.param_buf->length); 386 memcpy(gsmi_dev.param_buf->start, ¶m, sizeof(param)); 387 388 rc = gsmi_exec(GSMI_CALLBACK, GSMI_CMD_GET_NEXT_VAR); 389 if (rc < 0) { 390 printk(KERN_ERR "gsmi: Get Next Variable Name failed\n"); 391 ret = EFI_LOAD_ERROR; 392 } else if (rc == 1) { 393 /* variable not found -- end of list */ 394 ret = EFI_NOT_FOUND; 395 } else { 396 /* copy variable data back to return buffer */ 397 memcpy(¶m, gsmi_dev.param_buf->start, sizeof(param)); 398 399 /* Copy the name back */ 400 memcpy(name, gsmi_dev.name_buf->start, GSMI_BUF_SIZE); 401 *name_size = ucs2_strnlen(name, GSMI_BUF_SIZE / 2) * 2; 402 403 /* copy guid to return buffer */ 404 memcpy(vendor, ¶m.guid, sizeof(param.guid)); 405 ret = EFI_SUCCESS; 406 } 407 408 spin_unlock_irqrestore(&gsmi_dev.lock, flags); 409 410 return ret; 411 } 412 413 static efi_status_t gsmi_set_variable(efi_char16_t *name, 414 efi_guid_t *vendor, 415 u32 attr, 416 unsigned long data_size, 417 void *data) 418 { 419 struct gsmi_nvram_var_param param = { 420 .name_ptr = gsmi_dev.name_buf->address, 421 .data_ptr = gsmi_dev.data_buf->address, 422 .data_len = (u32)data_size, 423 .attributes = EFI_VARIABLE_NON_VOLATILE | 424 EFI_VARIABLE_BOOTSERVICE_ACCESS | 425 EFI_VARIABLE_RUNTIME_ACCESS, 426 }; 427 size_t name_len = ucs2_strnlen(name, GSMI_BUF_SIZE / 2); 428 efi_status_t ret = EFI_SUCCESS; 429 int rc; 430 unsigned long flags; 431 432 if (name_len >= GSMI_BUF_SIZE / 2) 433 return EFI_BAD_BUFFER_SIZE; 434 435 spin_lock_irqsave(&gsmi_dev.lock, flags); 436 437 /* guid */ 438 memcpy(¶m.guid, vendor, sizeof(param.guid)); 439 440 /* variable name, already in UTF-16 */ 441 memset(gsmi_dev.name_buf->start, 0, gsmi_dev.name_buf->length); 442 memcpy(gsmi_dev.name_buf->start, name, name_len * 2); 443 444 /* data pointer */ 445 memset(gsmi_dev.data_buf->start, 0, gsmi_dev.data_buf->length); 446 memcpy(gsmi_dev.data_buf->start, data, data_size); 447 448 /* parameter buffer */ 449 memset(gsmi_dev.param_buf->start, 0, gsmi_dev.param_buf->length); 450 memcpy(gsmi_dev.param_buf->start, ¶m, sizeof(param)); 451 452 rc = gsmi_exec(GSMI_CALLBACK, GSMI_CMD_SET_NVRAM_VAR); 453 if (rc < 0) { 454 printk(KERN_ERR "gsmi: Set Variable failed\n"); 455 ret = EFI_INVALID_PARAMETER; 456 } 457 458 spin_unlock_irqrestore(&gsmi_dev.lock, flags); 459 460 return ret; 461 } 462 463 static const struct efivar_operations efivar_ops = { 464 .get_variable = gsmi_get_variable, 465 .set_variable = gsmi_set_variable, 466 .get_next_variable = gsmi_get_next_variable, 467 }; 468 469 static ssize_t eventlog_write(struct file *filp, struct kobject *kobj, 470 struct bin_attribute *bin_attr, 471 char *buf, loff_t pos, size_t count) 472 { 473 struct gsmi_set_eventlog_param param = { 474 .data_ptr = gsmi_dev.data_buf->address, 475 }; 476 int rc = 0; 477 unsigned long flags; 478 479 /* Pull the type out */ 480 if (count < sizeof(u32)) 481 return -EINVAL; 482 param.type = *(u32 *)buf; 483 count -= sizeof(u32); 484 buf += sizeof(u32); 485 486 /* The remaining buffer is the data payload */ 487 if (count > gsmi_dev.data_buf->length) 488 return -EINVAL; 489 param.data_len = count - sizeof(u32); 490 491 spin_lock_irqsave(&gsmi_dev.lock, flags); 492 493 /* data pointer */ 494 memset(gsmi_dev.data_buf->start, 0, gsmi_dev.data_buf->length); 495 memcpy(gsmi_dev.data_buf->start, buf, param.data_len); 496 497 /* parameter buffer */ 498 memset(gsmi_dev.param_buf->start, 0, gsmi_dev.param_buf->length); 499 memcpy(gsmi_dev.param_buf->start, ¶m, sizeof(param)); 500 501 rc = gsmi_exec(GSMI_CALLBACK, GSMI_CMD_SET_EVENT_LOG); 502 if (rc < 0) 503 printk(KERN_ERR "gsmi: Set Event Log failed\n"); 504 505 spin_unlock_irqrestore(&gsmi_dev.lock, flags); 506 507 return rc; 508 509 } 510 511 static struct bin_attribute eventlog_bin_attr = { 512 .attr = {.name = "append_to_eventlog", .mode = 0200}, 513 .write = eventlog_write, 514 }; 515 516 static ssize_t gsmi_clear_eventlog_store(struct kobject *kobj, 517 struct kobj_attribute *attr, 518 const char *buf, size_t count) 519 { 520 int rc; 521 unsigned long flags; 522 unsigned long val; 523 struct { 524 u32 percentage; 525 u32 data_type; 526 } param; 527 528 rc = kstrtoul(buf, 0, &val); 529 if (rc) 530 return rc; 531 532 /* 533 * Value entered is a percentage, 0 through 100, anything else 534 * is invalid. 535 */ 536 if (val > 100) 537 return -EINVAL; 538 539 /* data_type here selects the smbios event log. */ 540 param.percentage = val; 541 param.data_type = 0; 542 543 spin_lock_irqsave(&gsmi_dev.lock, flags); 544 545 /* parameter buffer */ 546 memset(gsmi_dev.param_buf->start, 0, gsmi_dev.param_buf->length); 547 memcpy(gsmi_dev.param_buf->start, ¶m, sizeof(param)); 548 549 rc = gsmi_exec(GSMI_CALLBACK, GSMI_CMD_CLEAR_EVENT_LOG); 550 551 spin_unlock_irqrestore(&gsmi_dev.lock, flags); 552 553 if (rc) 554 return rc; 555 return count; 556 } 557 558 static struct kobj_attribute gsmi_clear_eventlog_attr = { 559 .attr = {.name = "clear_eventlog", .mode = 0200}, 560 .store = gsmi_clear_eventlog_store, 561 }; 562 563 static ssize_t gsmi_clear_config_store(struct kobject *kobj, 564 struct kobj_attribute *attr, 565 const char *buf, size_t count) 566 { 567 int rc; 568 unsigned long flags; 569 570 spin_lock_irqsave(&gsmi_dev.lock, flags); 571 572 /* clear parameter buffer */ 573 memset(gsmi_dev.param_buf->start, 0, gsmi_dev.param_buf->length); 574 575 rc = gsmi_exec(GSMI_CALLBACK, GSMI_CMD_CLEAR_CONFIG); 576 577 spin_unlock_irqrestore(&gsmi_dev.lock, flags); 578 579 if (rc) 580 return rc; 581 return count; 582 } 583 584 static struct kobj_attribute gsmi_clear_config_attr = { 585 .attr = {.name = "clear_config", .mode = 0200}, 586 .store = gsmi_clear_config_store, 587 }; 588 589 static const struct attribute *gsmi_attrs[] = { 590 &gsmi_clear_config_attr.attr, 591 &gsmi_clear_eventlog_attr.attr, 592 NULL, 593 }; 594 595 static int gsmi_shutdown_reason(int reason) 596 { 597 struct gsmi_log_entry_type_1 entry = { 598 .type = GSMI_LOG_ENTRY_TYPE_KERNEL, 599 .instance = reason, 600 }; 601 struct gsmi_set_eventlog_param param = { 602 .data_len = sizeof(entry), 603 .type = 1, 604 }; 605 static int saved_reason; 606 int rc = 0; 607 unsigned long flags; 608 609 /* avoid duplicate entries in the log */ 610 if (saved_reason & (1 << reason)) 611 return 0; 612 613 spin_lock_irqsave(&gsmi_dev.lock, flags); 614 615 saved_reason |= (1 << reason); 616 617 /* data pointer */ 618 memset(gsmi_dev.data_buf->start, 0, gsmi_dev.data_buf->length); 619 memcpy(gsmi_dev.data_buf->start, &entry, sizeof(entry)); 620 621 /* parameter buffer */ 622 param.data_ptr = gsmi_dev.data_buf->address; 623 memset(gsmi_dev.param_buf->start, 0, gsmi_dev.param_buf->length); 624 memcpy(gsmi_dev.param_buf->start, ¶m, sizeof(param)); 625 626 rc = gsmi_exec(GSMI_CALLBACK, GSMI_CMD_SET_EVENT_LOG); 627 628 spin_unlock_irqrestore(&gsmi_dev.lock, flags); 629 630 if (rc < 0) 631 printk(KERN_ERR "gsmi: Log Shutdown Reason failed\n"); 632 else 633 printk(KERN_EMERG "gsmi: Log Shutdown Reason 0x%02x\n", 634 reason); 635 636 return rc; 637 } 638 639 static int gsmi_reboot_callback(struct notifier_block *nb, 640 unsigned long reason, void *arg) 641 { 642 gsmi_shutdown_reason(GSMI_SHUTDOWN_CLEAN); 643 return NOTIFY_DONE; 644 } 645 646 static struct notifier_block gsmi_reboot_notifier = { 647 .notifier_call = gsmi_reboot_callback 648 }; 649 650 static int gsmi_die_callback(struct notifier_block *nb, 651 unsigned long reason, void *arg) 652 { 653 if (reason == DIE_OOPS) 654 gsmi_shutdown_reason(GSMI_SHUTDOWN_OOPS); 655 return NOTIFY_DONE; 656 } 657 658 static struct notifier_block gsmi_die_notifier = { 659 .notifier_call = gsmi_die_callback 660 }; 661 662 static int gsmi_panic_callback(struct notifier_block *nb, 663 unsigned long reason, void *arg) 664 { 665 gsmi_shutdown_reason(GSMI_SHUTDOWN_PANIC); 666 return NOTIFY_DONE; 667 } 668 669 static struct notifier_block gsmi_panic_notifier = { 670 .notifier_call = gsmi_panic_callback, 671 }; 672 673 /* 674 * This hash function was blatantly copied from include/linux/hash.h. 675 * It is used by this driver to obfuscate a board name that requires a 676 * quirk within this driver. 677 * 678 * Please do not remove this copy of the function as any changes to the 679 * global utility hash_64() function would break this driver's ability 680 * to identify a board and provide the appropriate quirk -- mikew@google.com 681 */ 682 static u64 __init local_hash_64(u64 val, unsigned bits) 683 { 684 u64 hash = val; 685 686 /* Sigh, gcc can't optimise this alone like it does for 32 bits. */ 687 u64 n = hash; 688 n <<= 18; 689 hash -= n; 690 n <<= 33; 691 hash -= n; 692 n <<= 3; 693 hash += n; 694 n <<= 3; 695 hash -= n; 696 n <<= 4; 697 hash += n; 698 n <<= 2; 699 hash += n; 700 701 /* High bits are more random, so use them. */ 702 return hash >> (64 - bits); 703 } 704 705 static u32 __init hash_oem_table_id(char s[8]) 706 { 707 u64 input; 708 memcpy(&input, s, 8); 709 return local_hash_64(input, 32); 710 } 711 712 static struct dmi_system_id gsmi_dmi_table[] __initdata = { 713 { 714 .ident = "Google Board", 715 .matches = { 716 DMI_MATCH(DMI_BOARD_VENDOR, "Google, Inc."), 717 }, 718 }, 719 {} 720 }; 721 MODULE_DEVICE_TABLE(dmi, gsmi_dmi_table); 722 723 static __init int gsmi_system_valid(void) 724 { 725 u32 hash; 726 727 if (!dmi_check_system(gsmi_dmi_table)) 728 return -ENODEV; 729 730 /* 731 * Only newer firmware supports the gsmi interface. All older 732 * firmware that didn't support this interface used to plug the 733 * table name in the first four bytes of the oem_table_id field. 734 * Newer firmware doesn't do that though, so use that as the 735 * discriminant factor. We have to do this in order to 736 * whitewash our board names out of the public driver. 737 */ 738 if (!strncmp(acpi_gbl_FADT.header.oem_table_id, "FACP", 4)) { 739 printk(KERN_INFO "gsmi: Board is too old\n"); 740 return -ENODEV; 741 } 742 743 /* Disable on board with 1.0 BIOS due to Google bug 2602657 */ 744 hash = hash_oem_table_id(acpi_gbl_FADT.header.oem_table_id); 745 if (hash == QUIRKY_BOARD_HASH) { 746 const char *bios_ver = dmi_get_system_info(DMI_BIOS_VERSION); 747 if (strncmp(bios_ver, "1.0", 3) == 0) { 748 pr_info("gsmi: disabled on this board's BIOS %s\n", 749 bios_ver); 750 return -ENODEV; 751 } 752 } 753 754 /* check for valid SMI command port in ACPI FADT */ 755 if (acpi_gbl_FADT.smi_command == 0) { 756 pr_info("gsmi: missing smi_command\n"); 757 return -ENODEV; 758 } 759 760 /* Found */ 761 return 0; 762 } 763 764 static struct kobject *gsmi_kobj; 765 static struct efivars efivars; 766 767 static const struct platform_device_info gsmi_dev_info = { 768 .name = "gsmi", 769 .id = -1, 770 /* SMI callbacks require 32bit addresses */ 771 .dma_mask = DMA_BIT_MASK(32), 772 }; 773 774 static __init int gsmi_init(void) 775 { 776 unsigned long flags; 777 int ret; 778 779 ret = gsmi_system_valid(); 780 if (ret) 781 return ret; 782 783 gsmi_dev.smi_cmd = acpi_gbl_FADT.smi_command; 784 785 /* register device */ 786 gsmi_dev.pdev = platform_device_register_full(&gsmi_dev_info); 787 if (IS_ERR(gsmi_dev.pdev)) { 788 printk(KERN_ERR "gsmi: unable to register platform device\n"); 789 return PTR_ERR(gsmi_dev.pdev); 790 } 791 792 /* SMI access needs to be serialized */ 793 spin_lock_init(&gsmi_dev.lock); 794 795 ret = -ENOMEM; 796 gsmi_dev.dma_pool = dma_pool_create("gsmi", &gsmi_dev.pdev->dev, 797 GSMI_BUF_SIZE, GSMI_BUF_ALIGN, 0); 798 if (!gsmi_dev.dma_pool) 799 goto out_err; 800 801 /* 802 * pre-allocate buffers because sometimes we are called when 803 * this is not feasible: oops, panic, die, mce, etc 804 */ 805 gsmi_dev.name_buf = gsmi_buf_alloc(); 806 if (!gsmi_dev.name_buf) { 807 printk(KERN_ERR "gsmi: failed to allocate name buffer\n"); 808 goto out_err; 809 } 810 811 gsmi_dev.data_buf = gsmi_buf_alloc(); 812 if (!gsmi_dev.data_buf) { 813 printk(KERN_ERR "gsmi: failed to allocate data buffer\n"); 814 goto out_err; 815 } 816 817 gsmi_dev.param_buf = gsmi_buf_alloc(); 818 if (!gsmi_dev.param_buf) { 819 printk(KERN_ERR "gsmi: failed to allocate param buffer\n"); 820 goto out_err; 821 } 822 823 /* 824 * Determine type of handshake used to serialize the SMI 825 * entry. See also gsmi_exec(). 826 * 827 * There's a "behavior" present on some chipsets where writing the 828 * SMI trigger register in the southbridge doesn't result in an 829 * immediate SMI. Rather, the processor can execute "a few" more 830 * instructions before the SMI takes effect. To ensure synchronous 831 * behavior, implement a handshake between the kernel driver and the 832 * firmware handler to spin until released. This ioctl determines 833 * the type of handshake. 834 * 835 * NONE: The firmware handler does not implement any 836 * handshake. Either it doesn't need to, or it's legacy firmware 837 * that doesn't know it needs to and never will. 838 * 839 * CF: The firmware handler will clear the CF in the saved 840 * state before returning. The driver may set the CF and test for 841 * it to clear before proceeding. 842 * 843 * SPIN: The firmware handler does not implement any handshake 844 * but the driver should spin for a hundred or so microseconds 845 * to ensure the SMI has triggered. 846 * 847 * Finally, the handler will return -ENOSYS if 848 * GSMI_CMD_HANDSHAKE_TYPE is unimplemented, which implies 849 * HANDSHAKE_NONE. 850 */ 851 spin_lock_irqsave(&gsmi_dev.lock, flags); 852 gsmi_dev.handshake_type = GSMI_HANDSHAKE_SPIN; 853 gsmi_dev.handshake_type = 854 gsmi_exec(GSMI_CALLBACK, GSMI_CMD_HANDSHAKE_TYPE); 855 if (gsmi_dev.handshake_type == -ENOSYS) 856 gsmi_dev.handshake_type = GSMI_HANDSHAKE_NONE; 857 spin_unlock_irqrestore(&gsmi_dev.lock, flags); 858 859 /* Remove and clean up gsmi if the handshake could not complete. */ 860 if (gsmi_dev.handshake_type == -ENXIO) { 861 printk(KERN_INFO "gsmi version " DRIVER_VERSION 862 " failed to load\n"); 863 ret = -ENODEV; 864 goto out_err; 865 } 866 867 /* Register in the firmware directory */ 868 ret = -ENOMEM; 869 gsmi_kobj = kobject_create_and_add("gsmi", firmware_kobj); 870 if (!gsmi_kobj) { 871 printk(KERN_INFO "gsmi: Failed to create firmware kobj\n"); 872 goto out_err; 873 } 874 875 /* Setup eventlog access */ 876 ret = sysfs_create_bin_file(gsmi_kobj, &eventlog_bin_attr); 877 if (ret) { 878 printk(KERN_INFO "gsmi: Failed to setup eventlog"); 879 goto out_err; 880 } 881 882 /* Other attributes */ 883 ret = sysfs_create_files(gsmi_kobj, gsmi_attrs); 884 if (ret) { 885 printk(KERN_INFO "gsmi: Failed to add attrs"); 886 goto out_remove_bin_file; 887 } 888 889 ret = efivars_register(&efivars, &efivar_ops, gsmi_kobj); 890 if (ret) { 891 printk(KERN_INFO "gsmi: Failed to register efivars\n"); 892 goto out_remove_sysfs_files; 893 } 894 895 register_reboot_notifier(&gsmi_reboot_notifier); 896 register_die_notifier(&gsmi_die_notifier); 897 atomic_notifier_chain_register(&panic_notifier_list, 898 &gsmi_panic_notifier); 899 900 printk(KERN_INFO "gsmi version " DRIVER_VERSION " loaded\n"); 901 902 return 0; 903 904 out_remove_sysfs_files: 905 sysfs_remove_files(gsmi_kobj, gsmi_attrs); 906 out_remove_bin_file: 907 sysfs_remove_bin_file(gsmi_kobj, &eventlog_bin_attr); 908 out_err: 909 kobject_put(gsmi_kobj); 910 gsmi_buf_free(gsmi_dev.param_buf); 911 gsmi_buf_free(gsmi_dev.data_buf); 912 gsmi_buf_free(gsmi_dev.name_buf); 913 if (gsmi_dev.dma_pool) 914 dma_pool_destroy(gsmi_dev.dma_pool); 915 platform_device_unregister(gsmi_dev.pdev); 916 pr_info("gsmi: failed to load: %d\n", ret); 917 return ret; 918 } 919 920 static void __exit gsmi_exit(void) 921 { 922 unregister_reboot_notifier(&gsmi_reboot_notifier); 923 unregister_die_notifier(&gsmi_die_notifier); 924 atomic_notifier_chain_unregister(&panic_notifier_list, 925 &gsmi_panic_notifier); 926 efivars_unregister(&efivars); 927 928 sysfs_remove_files(gsmi_kobj, gsmi_attrs); 929 sysfs_remove_bin_file(gsmi_kobj, &eventlog_bin_attr); 930 kobject_put(gsmi_kobj); 931 gsmi_buf_free(gsmi_dev.param_buf); 932 gsmi_buf_free(gsmi_dev.data_buf); 933 gsmi_buf_free(gsmi_dev.name_buf); 934 dma_pool_destroy(gsmi_dev.dma_pool); 935 platform_device_unregister(gsmi_dev.pdev); 936 } 937 938 module_init(gsmi_init); 939 module_exit(gsmi_exit); 940 941 MODULE_AUTHOR("Google, Inc."); 942 MODULE_LICENSE("GPL"); 943