1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * runtime-wrappers.c - Runtime Services function call wrappers 4 * 5 * Implementation summary: 6 * ----------------------- 7 * 1. When user/kernel thread requests to execute efi_runtime_service(), 8 * enqueue work to efi_rts_wq. 9 * 2. Caller thread waits for completion until the work is finished 10 * because it's dependent on the return status and execution of 11 * efi_runtime_service(). 12 * For instance, get_variable() and get_next_variable(). 13 * 14 * Copyright (C) 2014 Linaro Ltd. <ard.biesheuvel@linaro.org> 15 * 16 * Split off from arch/x86/platform/efi/efi.c 17 * 18 * Copyright (C) 1999 VA Linux Systems 19 * Copyright (C) 1999 Walt Drummond <drummond@valinux.com> 20 * Copyright (C) 1999-2002 Hewlett-Packard Co. 21 * Copyright (C) 2005-2008 Intel Co. 22 * Copyright (C) 2013 SuSE Labs 23 */ 24 25 #define pr_fmt(fmt) "efi: " fmt 26 27 #include <linux/bug.h> 28 #include <linux/efi.h> 29 #include <linux/irqflags.h> 30 #include <linux/mutex.h> 31 #include <linux/semaphore.h> 32 #include <linux/stringify.h> 33 #include <linux/workqueue.h> 34 #include <linux/completion.h> 35 36 #include <asm/efi.h> 37 38 /* 39 * Wrap around the new efi_call_virt_generic() macros so that the 40 * code doesn't get too cluttered: 41 */ 42 #define efi_call_virt(f, args...) \ 43 efi_call_virt_pointer(efi.systab->runtime, f, args) 44 #define __efi_call_virt(f, args...) \ 45 __efi_call_virt_pointer(efi.systab->runtime, f, args) 46 47 struct efi_runtime_work efi_rts_work; 48 49 /* 50 * efi_queue_work: Queue efi_runtime_service() and wait until it's done 51 * @rts: efi_runtime_service() function identifier 52 * @rts_arg<1-5>: efi_runtime_service() function arguments 53 * 54 * Accesses to efi_runtime_services() are serialized by a binary 55 * semaphore (efi_runtime_lock) and caller waits until the work is 56 * finished, hence _only_ one work is queued at a time and the caller 57 * thread waits for completion. 58 */ 59 #define efi_queue_work(_rts, _arg1, _arg2, _arg3, _arg4, _arg5) \ 60 ({ \ 61 efi_rts_work.status = EFI_ABORTED; \ 62 \ 63 if (!efi_enabled(EFI_RUNTIME_SERVICES)) { \ 64 pr_warn_once("EFI Runtime Services are disabled!\n"); \ 65 goto exit; \ 66 } \ 67 \ 68 init_completion(&efi_rts_work.efi_rts_comp); \ 69 INIT_WORK(&efi_rts_work.work, efi_call_rts); \ 70 efi_rts_work.arg1 = _arg1; \ 71 efi_rts_work.arg2 = _arg2; \ 72 efi_rts_work.arg3 = _arg3; \ 73 efi_rts_work.arg4 = _arg4; \ 74 efi_rts_work.arg5 = _arg5; \ 75 efi_rts_work.efi_rts_id = _rts; \ 76 \ 77 /* \ 78 * queue_work() returns 0 if work was already on queue, \ 79 * _ideally_ this should never happen. \ 80 */ \ 81 if (queue_work(efi_rts_wq, &efi_rts_work.work)) \ 82 wait_for_completion(&efi_rts_work.efi_rts_comp); \ 83 else \ 84 pr_err("Failed to queue work to efi_rts_wq.\n"); \ 85 \ 86 exit: \ 87 efi_rts_work.efi_rts_id = EFI_NONE; \ 88 efi_rts_work.status; \ 89 }) 90 91 #ifndef arch_efi_save_flags 92 #define arch_efi_save_flags(state_flags) local_save_flags(state_flags) 93 #define arch_efi_restore_flags(state_flags) local_irq_restore(state_flags) 94 #endif 95 96 unsigned long efi_call_virt_save_flags(void) 97 { 98 unsigned long flags; 99 100 arch_efi_save_flags(flags); 101 return flags; 102 } 103 104 void efi_call_virt_check_flags(unsigned long flags, const char *call) 105 { 106 unsigned long cur_flags, mismatch; 107 108 cur_flags = efi_call_virt_save_flags(); 109 110 mismatch = flags ^ cur_flags; 111 if (!WARN_ON_ONCE(mismatch & ARCH_EFI_IRQ_FLAGS_MASK)) 112 return; 113 114 add_taint(TAINT_FIRMWARE_WORKAROUND, LOCKDEP_NOW_UNRELIABLE); 115 pr_err_ratelimited(FW_BUG "IRQ flags corrupted (0x%08lx=>0x%08lx) by EFI %s\n", 116 flags, cur_flags, call); 117 arch_efi_restore_flags(flags); 118 } 119 120 /* 121 * According to section 7.1 of the UEFI spec, Runtime Services are not fully 122 * reentrant, and there are particular combinations of calls that need to be 123 * serialized. (source: UEFI Specification v2.4A) 124 * 125 * Table 31. Rules for Reentry Into Runtime Services 126 * +------------------------------------+-------------------------------+ 127 * | If previous call is busy in | Forbidden to call | 128 * +------------------------------------+-------------------------------+ 129 * | Any | SetVirtualAddressMap() | 130 * +------------------------------------+-------------------------------+ 131 * | ConvertPointer() | ConvertPointer() | 132 * +------------------------------------+-------------------------------+ 133 * | SetVariable() | ResetSystem() | 134 * | UpdateCapsule() | | 135 * | SetTime() | | 136 * | SetWakeupTime() | | 137 * | GetNextHighMonotonicCount() | | 138 * +------------------------------------+-------------------------------+ 139 * | GetVariable() | GetVariable() | 140 * | GetNextVariableName() | GetNextVariableName() | 141 * | SetVariable() | SetVariable() | 142 * | QueryVariableInfo() | QueryVariableInfo() | 143 * | UpdateCapsule() | UpdateCapsule() | 144 * | QueryCapsuleCapabilities() | QueryCapsuleCapabilities() | 145 * | GetNextHighMonotonicCount() | GetNextHighMonotonicCount() | 146 * +------------------------------------+-------------------------------+ 147 * | GetTime() | GetTime() | 148 * | SetTime() | SetTime() | 149 * | GetWakeupTime() | GetWakeupTime() | 150 * | SetWakeupTime() | SetWakeupTime() | 151 * +------------------------------------+-------------------------------+ 152 * 153 * Due to the fact that the EFI pstore may write to the variable store in 154 * interrupt context, we need to use a lock for at least the groups that 155 * contain SetVariable() and QueryVariableInfo(). That leaves little else, as 156 * none of the remaining functions are actually ever called at runtime. 157 * So let's just use a single lock to serialize all Runtime Services calls. 158 */ 159 static DEFINE_SEMAPHORE(efi_runtime_lock); 160 161 /* 162 * Expose the EFI runtime lock to the UV platform 163 */ 164 #ifdef CONFIG_X86_UV 165 extern struct semaphore __efi_uv_runtime_lock __alias(efi_runtime_lock); 166 #endif 167 168 /* 169 * Calls the appropriate efi_runtime_service() with the appropriate 170 * arguments. 171 * 172 * Semantics followed by efi_call_rts() to understand efi_runtime_work: 173 * 1. If argument was a pointer, recast it from void pointer to original 174 * pointer type. 175 * 2. If argument was a value, recast it from void pointer to original 176 * pointer type and dereference it. 177 */ 178 static void efi_call_rts(struct work_struct *work) 179 { 180 void *arg1, *arg2, *arg3, *arg4, *arg5; 181 efi_status_t status = EFI_NOT_FOUND; 182 183 arg1 = efi_rts_work.arg1; 184 arg2 = efi_rts_work.arg2; 185 arg3 = efi_rts_work.arg3; 186 arg4 = efi_rts_work.arg4; 187 arg5 = efi_rts_work.arg5; 188 189 switch (efi_rts_work.efi_rts_id) { 190 case EFI_GET_TIME: 191 status = efi_call_virt(get_time, (efi_time_t *)arg1, 192 (efi_time_cap_t *)arg2); 193 break; 194 case EFI_SET_TIME: 195 status = efi_call_virt(set_time, (efi_time_t *)arg1); 196 break; 197 case EFI_GET_WAKEUP_TIME: 198 status = efi_call_virt(get_wakeup_time, (efi_bool_t *)arg1, 199 (efi_bool_t *)arg2, (efi_time_t *)arg3); 200 break; 201 case EFI_SET_WAKEUP_TIME: 202 status = efi_call_virt(set_wakeup_time, *(efi_bool_t *)arg1, 203 (efi_time_t *)arg2); 204 break; 205 case EFI_GET_VARIABLE: 206 status = efi_call_virt(get_variable, (efi_char16_t *)arg1, 207 (efi_guid_t *)arg2, (u32 *)arg3, 208 (unsigned long *)arg4, (void *)arg5); 209 break; 210 case EFI_GET_NEXT_VARIABLE: 211 status = efi_call_virt(get_next_variable, (unsigned long *)arg1, 212 (efi_char16_t *)arg2, 213 (efi_guid_t *)arg3); 214 break; 215 case EFI_SET_VARIABLE: 216 status = efi_call_virt(set_variable, (efi_char16_t *)arg1, 217 (efi_guid_t *)arg2, *(u32 *)arg3, 218 *(unsigned long *)arg4, (void *)arg5); 219 break; 220 case EFI_QUERY_VARIABLE_INFO: 221 status = efi_call_virt(query_variable_info, *(u32 *)arg1, 222 (u64 *)arg2, (u64 *)arg3, (u64 *)arg4); 223 break; 224 case EFI_GET_NEXT_HIGH_MONO_COUNT: 225 status = efi_call_virt(get_next_high_mono_count, (u32 *)arg1); 226 break; 227 case EFI_UPDATE_CAPSULE: 228 status = efi_call_virt(update_capsule, 229 (efi_capsule_header_t **)arg1, 230 *(unsigned long *)arg2, 231 *(unsigned long *)arg3); 232 break; 233 case EFI_QUERY_CAPSULE_CAPS: 234 status = efi_call_virt(query_capsule_caps, 235 (efi_capsule_header_t **)arg1, 236 *(unsigned long *)arg2, (u64 *)arg3, 237 (int *)arg4); 238 break; 239 default: 240 /* 241 * Ideally, we should never reach here because a caller of this 242 * function should have put the right efi_runtime_service() 243 * function identifier into efi_rts_work->efi_rts_id 244 */ 245 pr_err("Requested executing invalid EFI Runtime Service.\n"); 246 } 247 efi_rts_work.status = status; 248 complete(&efi_rts_work.efi_rts_comp); 249 } 250 251 static efi_status_t virt_efi_get_time(efi_time_t *tm, efi_time_cap_t *tc) 252 { 253 efi_status_t status; 254 255 if (down_interruptible(&efi_runtime_lock)) 256 return EFI_ABORTED; 257 status = efi_queue_work(EFI_GET_TIME, tm, tc, NULL, NULL, NULL); 258 up(&efi_runtime_lock); 259 return status; 260 } 261 262 static efi_status_t virt_efi_set_time(efi_time_t *tm) 263 { 264 efi_status_t status; 265 266 if (down_interruptible(&efi_runtime_lock)) 267 return EFI_ABORTED; 268 status = efi_queue_work(EFI_SET_TIME, tm, NULL, NULL, NULL, NULL); 269 up(&efi_runtime_lock); 270 return status; 271 } 272 273 static efi_status_t virt_efi_get_wakeup_time(efi_bool_t *enabled, 274 efi_bool_t *pending, 275 efi_time_t *tm) 276 { 277 efi_status_t status; 278 279 if (down_interruptible(&efi_runtime_lock)) 280 return EFI_ABORTED; 281 status = efi_queue_work(EFI_GET_WAKEUP_TIME, enabled, pending, tm, NULL, 282 NULL); 283 up(&efi_runtime_lock); 284 return status; 285 } 286 287 static efi_status_t virt_efi_set_wakeup_time(efi_bool_t enabled, efi_time_t *tm) 288 { 289 efi_status_t status; 290 291 if (down_interruptible(&efi_runtime_lock)) 292 return EFI_ABORTED; 293 status = efi_queue_work(EFI_SET_WAKEUP_TIME, &enabled, tm, NULL, NULL, 294 NULL); 295 up(&efi_runtime_lock); 296 return status; 297 } 298 299 static efi_status_t virt_efi_get_variable(efi_char16_t *name, 300 efi_guid_t *vendor, 301 u32 *attr, 302 unsigned long *data_size, 303 void *data) 304 { 305 efi_status_t status; 306 307 if (down_interruptible(&efi_runtime_lock)) 308 return EFI_ABORTED; 309 status = efi_queue_work(EFI_GET_VARIABLE, name, vendor, attr, data_size, 310 data); 311 up(&efi_runtime_lock); 312 return status; 313 } 314 315 static efi_status_t virt_efi_get_next_variable(unsigned long *name_size, 316 efi_char16_t *name, 317 efi_guid_t *vendor) 318 { 319 efi_status_t status; 320 321 if (down_interruptible(&efi_runtime_lock)) 322 return EFI_ABORTED; 323 status = efi_queue_work(EFI_GET_NEXT_VARIABLE, name_size, name, vendor, 324 NULL, NULL); 325 up(&efi_runtime_lock); 326 return status; 327 } 328 329 static efi_status_t virt_efi_set_variable(efi_char16_t *name, 330 efi_guid_t *vendor, 331 u32 attr, 332 unsigned long data_size, 333 void *data) 334 { 335 efi_status_t status; 336 337 if (down_interruptible(&efi_runtime_lock)) 338 return EFI_ABORTED; 339 status = efi_queue_work(EFI_SET_VARIABLE, name, vendor, &attr, &data_size, 340 data); 341 up(&efi_runtime_lock); 342 return status; 343 } 344 345 static efi_status_t 346 virt_efi_set_variable_nonblocking(efi_char16_t *name, efi_guid_t *vendor, 347 u32 attr, unsigned long data_size, 348 void *data) 349 { 350 efi_status_t status; 351 352 if (down_trylock(&efi_runtime_lock)) 353 return EFI_NOT_READY; 354 355 status = efi_call_virt(set_variable, name, vendor, attr, data_size, 356 data); 357 up(&efi_runtime_lock); 358 return status; 359 } 360 361 362 static efi_status_t virt_efi_query_variable_info(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_interruptible(&efi_runtime_lock)) 373 return EFI_ABORTED; 374 status = efi_queue_work(EFI_QUERY_VARIABLE_INFO, &attr, storage_space, 375 remaining_space, max_variable_size, NULL); 376 up(&efi_runtime_lock); 377 return status; 378 } 379 380 static efi_status_t 381 virt_efi_query_variable_info_nonblocking(u32 attr, 382 u64 *storage_space, 383 u64 *remaining_space, 384 u64 *max_variable_size) 385 { 386 efi_status_t status; 387 388 if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION) 389 return EFI_UNSUPPORTED; 390 391 if (down_trylock(&efi_runtime_lock)) 392 return EFI_NOT_READY; 393 394 status = efi_call_virt(query_variable_info, attr, storage_space, 395 remaining_space, max_variable_size); 396 up(&efi_runtime_lock); 397 return status; 398 } 399 400 static efi_status_t virt_efi_get_next_high_mono_count(u32 *count) 401 { 402 efi_status_t status; 403 404 if (down_interruptible(&efi_runtime_lock)) 405 return EFI_ABORTED; 406 status = efi_queue_work(EFI_GET_NEXT_HIGH_MONO_COUNT, count, NULL, NULL, 407 NULL, NULL); 408 up(&efi_runtime_lock); 409 return status; 410 } 411 412 static void virt_efi_reset_system(int reset_type, 413 efi_status_t status, 414 unsigned long data_size, 415 efi_char16_t *data) 416 { 417 if (down_interruptible(&efi_runtime_lock)) { 418 pr_warn("failed to invoke the reset_system() runtime service:\n" 419 "could not get exclusive access to the firmware\n"); 420 return; 421 } 422 efi_rts_work.efi_rts_id = EFI_RESET_SYSTEM; 423 __efi_call_virt(reset_system, reset_type, status, data_size, data); 424 up(&efi_runtime_lock); 425 } 426 427 static efi_status_t virt_efi_update_capsule(efi_capsule_header_t **capsules, 428 unsigned long count, 429 unsigned long sg_list) 430 { 431 efi_status_t status; 432 433 if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION) 434 return EFI_UNSUPPORTED; 435 436 if (down_interruptible(&efi_runtime_lock)) 437 return EFI_ABORTED; 438 status = efi_queue_work(EFI_UPDATE_CAPSULE, capsules, &count, &sg_list, 439 NULL, NULL); 440 up(&efi_runtime_lock); 441 return status; 442 } 443 444 static efi_status_t virt_efi_query_capsule_caps(efi_capsule_header_t **capsules, 445 unsigned long count, 446 u64 *max_size, 447 int *reset_type) 448 { 449 efi_status_t status; 450 451 if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION) 452 return EFI_UNSUPPORTED; 453 454 if (down_interruptible(&efi_runtime_lock)) 455 return EFI_ABORTED; 456 status = efi_queue_work(EFI_QUERY_CAPSULE_CAPS, capsules, &count, 457 max_size, reset_type, NULL); 458 up(&efi_runtime_lock); 459 return status; 460 } 461 462 void efi_native_runtime_setup(void) 463 { 464 efi.get_time = virt_efi_get_time; 465 efi.set_time = virt_efi_set_time; 466 efi.get_wakeup_time = virt_efi_get_wakeup_time; 467 efi.set_wakeup_time = virt_efi_set_wakeup_time; 468 efi.get_variable = virt_efi_get_variable; 469 efi.get_next_variable = virt_efi_get_next_variable; 470 efi.set_variable = virt_efi_set_variable; 471 efi.set_variable_nonblocking = virt_efi_set_variable_nonblocking; 472 efi.get_next_high_mono_count = virt_efi_get_next_high_mono_count; 473 efi.reset_system = virt_efi_reset_system; 474 efi.query_variable_info = virt_efi_query_variable_info; 475 efi.query_variable_info_nonblocking = virt_efi_query_variable_info_nonblocking; 476 efi.update_capsule = virt_efi_update_capsule; 477 efi.query_capsule_caps = virt_efi_query_capsule_caps; 478 } 479