1 /* 2 * runtime-wrappers.c - Runtime Services function call wrappers 3 * 4 * Implementation summary: 5 * ----------------------- 6 * 1. When user/kernel thread requests to execute efi_runtime_service(), 7 * enqueue work to efi_rts_wq. 8 * 2. Caller thread waits for completion until the work is finished 9 * because it's dependent on the return status and execution of 10 * efi_runtime_service(). 11 * For instance, get_variable() and get_next_variable(). 12 * 13 * Copyright (C) 2014 Linaro Ltd. <ard.biesheuvel@linaro.org> 14 * 15 * Split off from arch/x86/platform/efi/efi.c 16 * 17 * Copyright (C) 1999 VA Linux Systems 18 * Copyright (C) 1999 Walt Drummond <drummond@valinux.com> 19 * Copyright (C) 1999-2002 Hewlett-Packard Co. 20 * Copyright (C) 2005-2008 Intel Co. 21 * Copyright (C) 2013 SuSE Labs 22 * 23 * This file is released under the GPLv2. 24 */ 25 26 #define pr_fmt(fmt) "efi: " fmt 27 28 #include <linux/bug.h> 29 #include <linux/efi.h> 30 #include <linux/irqflags.h> 31 #include <linux/mutex.h> 32 #include <linux/semaphore.h> 33 #include <linux/stringify.h> 34 #include <linux/workqueue.h> 35 #include <linux/completion.h> 36 37 #include <asm/efi.h> 38 39 /* 40 * Wrap around the new efi_call_virt_generic() macros so that the 41 * code doesn't get too cluttered: 42 */ 43 #define efi_call_virt(f, args...) \ 44 efi_call_virt_pointer(efi.systab->runtime, f, args) 45 #define __efi_call_virt(f, args...) \ 46 __efi_call_virt_pointer(efi.systab->runtime, f, args) 47 48 struct efi_runtime_work efi_rts_work; 49 50 /* 51 * efi_queue_work: Queue efi_runtime_service() and wait until it's done 52 * @rts: efi_runtime_service() function identifier 53 * @rts_arg<1-5>: efi_runtime_service() function arguments 54 * 55 * Accesses to efi_runtime_services() are serialized by a binary 56 * semaphore (efi_runtime_lock) and caller waits until the work is 57 * finished, hence _only_ one work is queued at a time and the caller 58 * thread waits for completion. 59 */ 60 #define efi_queue_work(_rts, _arg1, _arg2, _arg3, _arg4, _arg5) \ 61 ({ \ 62 efi_rts_work.status = EFI_ABORTED; \ 63 \ 64 if (!efi_enabled(EFI_RUNTIME_SERVICES)) { \ 65 pr_warn_once("EFI Runtime Services are disabled!\n"); \ 66 goto exit; \ 67 } \ 68 \ 69 init_completion(&efi_rts_work.efi_rts_comp); \ 70 INIT_WORK_ONSTACK(&efi_rts_work.work, efi_call_rts); \ 71 efi_rts_work.arg1 = _arg1; \ 72 efi_rts_work.arg2 = _arg2; \ 73 efi_rts_work.arg3 = _arg3; \ 74 efi_rts_work.arg4 = _arg4; \ 75 efi_rts_work.arg5 = _arg5; \ 76 efi_rts_work.efi_rts_id = _rts; \ 77 \ 78 /* \ 79 * queue_work() returns 0 if work was already on queue, \ 80 * _ideally_ this should never happen. \ 81 */ \ 82 if (queue_work(efi_rts_wq, &efi_rts_work.work)) \ 83 wait_for_completion(&efi_rts_work.efi_rts_comp); \ 84 else \ 85 pr_err("Failed to queue work to efi_rts_wq.\n"); \ 86 \ 87 exit: \ 88 efi_rts_work.efi_rts_id = NONE; \ 89 efi_rts_work.status; \ 90 }) 91 92 void efi_call_virt_check_flags(unsigned long flags, const char *call) 93 { 94 unsigned long cur_flags, mismatch; 95 96 local_save_flags(cur_flags); 97 98 mismatch = flags ^ cur_flags; 99 if (!WARN_ON_ONCE(mismatch & ARCH_EFI_IRQ_FLAGS_MASK)) 100 return; 101 102 add_taint(TAINT_FIRMWARE_WORKAROUND, LOCKDEP_NOW_UNRELIABLE); 103 pr_err_ratelimited(FW_BUG "IRQ flags corrupted (0x%08lx=>0x%08lx) by EFI %s\n", 104 flags, cur_flags, call); 105 local_irq_restore(flags); 106 } 107 108 /* 109 * According to section 7.1 of the UEFI spec, Runtime Services are not fully 110 * reentrant, and there are particular combinations of calls that need to be 111 * serialized. (source: UEFI Specification v2.4A) 112 * 113 * Table 31. Rules for Reentry Into Runtime Services 114 * +------------------------------------+-------------------------------+ 115 * | If previous call is busy in | Forbidden to call | 116 * +------------------------------------+-------------------------------+ 117 * | Any | SetVirtualAddressMap() | 118 * +------------------------------------+-------------------------------+ 119 * | ConvertPointer() | ConvertPointer() | 120 * +------------------------------------+-------------------------------+ 121 * | SetVariable() | ResetSystem() | 122 * | UpdateCapsule() | | 123 * | SetTime() | | 124 * | SetWakeupTime() | | 125 * | GetNextHighMonotonicCount() | | 126 * +------------------------------------+-------------------------------+ 127 * | GetVariable() | GetVariable() | 128 * | GetNextVariableName() | GetNextVariableName() | 129 * | SetVariable() | SetVariable() | 130 * | QueryVariableInfo() | QueryVariableInfo() | 131 * | UpdateCapsule() | UpdateCapsule() | 132 * | QueryCapsuleCapabilities() | QueryCapsuleCapabilities() | 133 * | GetNextHighMonotonicCount() | GetNextHighMonotonicCount() | 134 * +------------------------------------+-------------------------------+ 135 * | GetTime() | GetTime() | 136 * | SetTime() | SetTime() | 137 * | GetWakeupTime() | GetWakeupTime() | 138 * | SetWakeupTime() | SetWakeupTime() | 139 * +------------------------------------+-------------------------------+ 140 * 141 * Due to the fact that the EFI pstore may write to the variable store in 142 * interrupt context, we need to use a lock for at least the groups that 143 * contain SetVariable() and QueryVariableInfo(). That leaves little else, as 144 * none of the remaining functions are actually ever called at runtime. 145 * So let's just use a single lock to serialize all Runtime Services calls. 146 */ 147 static DEFINE_SEMAPHORE(efi_runtime_lock); 148 149 /* 150 * Calls the appropriate efi_runtime_service() with the appropriate 151 * arguments. 152 * 153 * Semantics followed by efi_call_rts() to understand efi_runtime_work: 154 * 1. If argument was a pointer, recast it from void pointer to original 155 * pointer type. 156 * 2. If argument was a value, recast it from void pointer to original 157 * pointer type and dereference it. 158 */ 159 static void efi_call_rts(struct work_struct *work) 160 { 161 void *arg1, *arg2, *arg3, *arg4, *arg5; 162 efi_status_t status = EFI_NOT_FOUND; 163 164 arg1 = efi_rts_work.arg1; 165 arg2 = efi_rts_work.arg2; 166 arg3 = efi_rts_work.arg3; 167 arg4 = efi_rts_work.arg4; 168 arg5 = efi_rts_work.arg5; 169 170 switch (efi_rts_work.efi_rts_id) { 171 case GET_TIME: 172 status = efi_call_virt(get_time, (efi_time_t *)arg1, 173 (efi_time_cap_t *)arg2); 174 break; 175 case SET_TIME: 176 status = efi_call_virt(set_time, (efi_time_t *)arg1); 177 break; 178 case GET_WAKEUP_TIME: 179 status = efi_call_virt(get_wakeup_time, (efi_bool_t *)arg1, 180 (efi_bool_t *)arg2, (efi_time_t *)arg3); 181 break; 182 case SET_WAKEUP_TIME: 183 status = efi_call_virt(set_wakeup_time, *(efi_bool_t *)arg1, 184 (efi_time_t *)arg2); 185 break; 186 case GET_VARIABLE: 187 status = efi_call_virt(get_variable, (efi_char16_t *)arg1, 188 (efi_guid_t *)arg2, (u32 *)arg3, 189 (unsigned long *)arg4, (void *)arg5); 190 break; 191 case GET_NEXT_VARIABLE: 192 status = efi_call_virt(get_next_variable, (unsigned long *)arg1, 193 (efi_char16_t *)arg2, 194 (efi_guid_t *)arg3); 195 break; 196 case SET_VARIABLE: 197 status = efi_call_virt(set_variable, (efi_char16_t *)arg1, 198 (efi_guid_t *)arg2, *(u32 *)arg3, 199 *(unsigned long *)arg4, (void *)arg5); 200 break; 201 case QUERY_VARIABLE_INFO: 202 status = efi_call_virt(query_variable_info, *(u32 *)arg1, 203 (u64 *)arg2, (u64 *)arg3, (u64 *)arg4); 204 break; 205 case GET_NEXT_HIGH_MONO_COUNT: 206 status = efi_call_virt(get_next_high_mono_count, (u32 *)arg1); 207 break; 208 case UPDATE_CAPSULE: 209 status = efi_call_virt(update_capsule, 210 (efi_capsule_header_t **)arg1, 211 *(unsigned long *)arg2, 212 *(unsigned long *)arg3); 213 break; 214 case QUERY_CAPSULE_CAPS: 215 status = efi_call_virt(query_capsule_caps, 216 (efi_capsule_header_t **)arg1, 217 *(unsigned long *)arg2, (u64 *)arg3, 218 (int *)arg4); 219 break; 220 default: 221 /* 222 * Ideally, we should never reach here because a caller of this 223 * function should have put the right efi_runtime_service() 224 * function identifier into efi_rts_work->efi_rts_id 225 */ 226 pr_err("Requested executing invalid EFI Runtime Service.\n"); 227 } 228 efi_rts_work.status = status; 229 complete(&efi_rts_work.efi_rts_comp); 230 } 231 232 static efi_status_t virt_efi_get_time(efi_time_t *tm, efi_time_cap_t *tc) 233 { 234 efi_status_t status; 235 236 if (down_interruptible(&efi_runtime_lock)) 237 return EFI_ABORTED; 238 status = efi_queue_work(GET_TIME, tm, tc, NULL, NULL, NULL); 239 up(&efi_runtime_lock); 240 return status; 241 } 242 243 static efi_status_t virt_efi_set_time(efi_time_t *tm) 244 { 245 efi_status_t status; 246 247 if (down_interruptible(&efi_runtime_lock)) 248 return EFI_ABORTED; 249 status = efi_queue_work(SET_TIME, tm, NULL, NULL, NULL, NULL); 250 up(&efi_runtime_lock); 251 return status; 252 } 253 254 static efi_status_t virt_efi_get_wakeup_time(efi_bool_t *enabled, 255 efi_bool_t *pending, 256 efi_time_t *tm) 257 { 258 efi_status_t status; 259 260 if (down_interruptible(&efi_runtime_lock)) 261 return EFI_ABORTED; 262 status = efi_queue_work(GET_WAKEUP_TIME, enabled, pending, tm, NULL, 263 NULL); 264 up(&efi_runtime_lock); 265 return status; 266 } 267 268 static efi_status_t virt_efi_set_wakeup_time(efi_bool_t enabled, efi_time_t *tm) 269 { 270 efi_status_t status; 271 272 if (down_interruptible(&efi_runtime_lock)) 273 return EFI_ABORTED; 274 status = efi_queue_work(SET_WAKEUP_TIME, &enabled, tm, NULL, NULL, 275 NULL); 276 up(&efi_runtime_lock); 277 return status; 278 } 279 280 static efi_status_t virt_efi_get_variable(efi_char16_t *name, 281 efi_guid_t *vendor, 282 u32 *attr, 283 unsigned long *data_size, 284 void *data) 285 { 286 efi_status_t status; 287 288 if (down_interruptible(&efi_runtime_lock)) 289 return EFI_ABORTED; 290 status = efi_queue_work(GET_VARIABLE, name, vendor, attr, data_size, 291 data); 292 up(&efi_runtime_lock); 293 return status; 294 } 295 296 static efi_status_t virt_efi_get_next_variable(unsigned long *name_size, 297 efi_char16_t *name, 298 efi_guid_t *vendor) 299 { 300 efi_status_t status; 301 302 if (down_interruptible(&efi_runtime_lock)) 303 return EFI_ABORTED; 304 status = efi_queue_work(GET_NEXT_VARIABLE, name_size, name, vendor, 305 NULL, NULL); 306 up(&efi_runtime_lock); 307 return status; 308 } 309 310 static efi_status_t virt_efi_set_variable(efi_char16_t *name, 311 efi_guid_t *vendor, 312 u32 attr, 313 unsigned long data_size, 314 void *data) 315 { 316 efi_status_t status; 317 318 if (down_interruptible(&efi_runtime_lock)) 319 return EFI_ABORTED; 320 status = efi_queue_work(SET_VARIABLE, name, vendor, &attr, &data_size, 321 data); 322 up(&efi_runtime_lock); 323 return status; 324 } 325 326 static efi_status_t 327 virt_efi_set_variable_nonblocking(efi_char16_t *name, efi_guid_t *vendor, 328 u32 attr, unsigned long data_size, 329 void *data) 330 { 331 efi_status_t status; 332 333 if (down_trylock(&efi_runtime_lock)) 334 return EFI_NOT_READY; 335 336 status = efi_call_virt(set_variable, name, vendor, attr, data_size, 337 data); 338 up(&efi_runtime_lock); 339 return status; 340 } 341 342 343 static efi_status_t virt_efi_query_variable_info(u32 attr, 344 u64 *storage_space, 345 u64 *remaining_space, 346 u64 *max_variable_size) 347 { 348 efi_status_t status; 349 350 if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION) 351 return EFI_UNSUPPORTED; 352 353 if (down_interruptible(&efi_runtime_lock)) 354 return EFI_ABORTED; 355 status = efi_queue_work(QUERY_VARIABLE_INFO, &attr, storage_space, 356 remaining_space, max_variable_size, NULL); 357 up(&efi_runtime_lock); 358 return status; 359 } 360 361 static efi_status_t 362 virt_efi_query_variable_info_nonblocking(u32 attr, 363 u64 *storage_space, 364 u64 *remaining_space, 365 u64 *max_variable_size) 366 { 367 efi_status_t status; 368 369 if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION) 370 return EFI_UNSUPPORTED; 371 372 if (down_trylock(&efi_runtime_lock)) 373 return EFI_NOT_READY; 374 375 status = efi_call_virt(query_variable_info, attr, storage_space, 376 remaining_space, max_variable_size); 377 up(&efi_runtime_lock); 378 return status; 379 } 380 381 static efi_status_t virt_efi_get_next_high_mono_count(u32 *count) 382 { 383 efi_status_t status; 384 385 if (down_interruptible(&efi_runtime_lock)) 386 return EFI_ABORTED; 387 status = efi_queue_work(GET_NEXT_HIGH_MONO_COUNT, count, NULL, NULL, 388 NULL, NULL); 389 up(&efi_runtime_lock); 390 return status; 391 } 392 393 static void virt_efi_reset_system(int reset_type, 394 efi_status_t status, 395 unsigned long data_size, 396 efi_char16_t *data) 397 { 398 if (down_interruptible(&efi_runtime_lock)) { 399 pr_warn("failed to invoke the reset_system() runtime service:\n" 400 "could not get exclusive access to the firmware\n"); 401 return; 402 } 403 efi_rts_work.efi_rts_id = RESET_SYSTEM; 404 __efi_call_virt(reset_system, reset_type, status, data_size, data); 405 up(&efi_runtime_lock); 406 } 407 408 static efi_status_t virt_efi_update_capsule(efi_capsule_header_t **capsules, 409 unsigned long count, 410 unsigned long sg_list) 411 { 412 efi_status_t status; 413 414 if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION) 415 return EFI_UNSUPPORTED; 416 417 if (down_interruptible(&efi_runtime_lock)) 418 return EFI_ABORTED; 419 status = efi_queue_work(UPDATE_CAPSULE, capsules, &count, &sg_list, 420 NULL, NULL); 421 up(&efi_runtime_lock); 422 return status; 423 } 424 425 static efi_status_t virt_efi_query_capsule_caps(efi_capsule_header_t **capsules, 426 unsigned long count, 427 u64 *max_size, 428 int *reset_type) 429 { 430 efi_status_t status; 431 432 if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION) 433 return EFI_UNSUPPORTED; 434 435 if (down_interruptible(&efi_runtime_lock)) 436 return EFI_ABORTED; 437 status = efi_queue_work(QUERY_CAPSULE_CAPS, capsules, &count, 438 max_size, reset_type, NULL); 439 up(&efi_runtime_lock); 440 return status; 441 } 442 443 void efi_native_runtime_setup(void) 444 { 445 efi.get_time = virt_efi_get_time; 446 efi.set_time = virt_efi_set_time; 447 efi.get_wakeup_time = virt_efi_get_wakeup_time; 448 efi.set_wakeup_time = virt_efi_set_wakeup_time; 449 efi.get_variable = virt_efi_get_variable; 450 efi.get_next_variable = virt_efi_get_next_variable; 451 efi.set_variable = virt_efi_set_variable; 452 efi.set_variable_nonblocking = virt_efi_set_variable_nonblocking; 453 efi.get_next_high_mono_count = virt_efi_get_next_high_mono_count; 454 efi.reset_system = virt_efi_reset_system; 455 efi.query_variable_info = virt_efi_query_variable_info; 456 efi.query_variable_info_nonblocking = virt_efi_query_variable_info_nonblocking; 457 efi.update_capsule = virt_efi_update_capsule; 458 efi.query_capsule_caps = virt_efi_query_capsule_caps; 459 } 460