// SPDX-License-Identifier: GPL-2.0-only /* * runtime-wrappers.c - Runtime Services function call wrappers * * Implementation summary: * ----------------------- * 1. When user/kernel thread requests to execute efi_runtime_service(), * enqueue work to efi_rts_wq. * 2. Caller thread waits for completion until the work is finished * because it's dependent on the return status and execution of * efi_runtime_service(). * For instance, get_variable() and get_next_variable(). * * Copyright (C) 2014 Linaro Ltd. * * Split off from arch/x86/platform/efi/efi.c * * Copyright (C) 1999 VA Linux Systems * Copyright (C) 1999 Walt Drummond * Copyright (C) 1999-2002 Hewlett-Packard Co. * Copyright (C) 2005-2008 Intel Co. * Copyright (C) 2013 SuSE Labs */ #define pr_fmt(fmt) "efi: " fmt #include #include #include #include #include #include #include #include #include /* * Wrap around the new efi_call_virt_generic() macros so that the * code doesn't get too cluttered: */ #define efi_call_virt(f, args...) \ efi_call_virt_pointer(efi.runtime, f, args) #define __efi_call_virt(f, args...) \ __efi_call_virt_pointer(efi.runtime, f, args) struct efi_runtime_work efi_rts_work; /* * efi_queue_work: Queue efi_runtime_service() and wait until it's done * @rts: efi_runtime_service() function identifier * @rts_arg<1-5>: efi_runtime_service() function arguments * * Accesses to efi_runtime_services() are serialized by a binary * semaphore (efi_runtime_lock) and caller waits until the work is * finished, hence _only_ one work is queued at a time and the caller * thread waits for completion. */ #define efi_queue_work(_rts, _arg1, _arg2, _arg3, _arg4, _arg5) \ ({ \ efi_rts_work.status = EFI_ABORTED; \ \ if (!efi_enabled(EFI_RUNTIME_SERVICES)) { \ pr_warn_once("EFI Runtime Services are disabled!\n"); \ goto exit; \ } \ \ init_completion(&efi_rts_work.efi_rts_comp); \ INIT_WORK(&efi_rts_work.work, efi_call_rts); \ efi_rts_work.arg1 = _arg1; \ efi_rts_work.arg2 = _arg2; \ efi_rts_work.arg3 = _arg3; \ efi_rts_work.arg4 = _arg4; \ efi_rts_work.arg5 = _arg5; \ efi_rts_work.efi_rts_id = _rts; \ \ /* \ * queue_work() returns 0 if work was already on queue, \ * _ideally_ this should never happen. \ */ \ if (queue_work(efi_rts_wq, &efi_rts_work.work)) \ wait_for_completion(&efi_rts_work.efi_rts_comp); \ else \ pr_err("Failed to queue work to efi_rts_wq.\n"); \ \ WARN_ON_ONCE(efi_rts_work.status == EFI_ABORTED); \ exit: \ efi_rts_work.efi_rts_id = EFI_NONE; \ efi_rts_work.status; \ }) #ifndef arch_efi_save_flags #define arch_efi_save_flags(state_flags) local_save_flags(state_flags) #define arch_efi_restore_flags(state_flags) local_irq_restore(state_flags) #endif unsigned long efi_call_virt_save_flags(void) { unsigned long flags; arch_efi_save_flags(flags); return flags; } void efi_call_virt_check_flags(unsigned long flags, const char *call) { unsigned long cur_flags, mismatch; cur_flags = efi_call_virt_save_flags(); mismatch = flags ^ cur_flags; if (!WARN_ON_ONCE(mismatch & ARCH_EFI_IRQ_FLAGS_MASK)) return; add_taint(TAINT_FIRMWARE_WORKAROUND, LOCKDEP_NOW_UNRELIABLE); pr_err_ratelimited(FW_BUG "IRQ flags corrupted (0x%08lx=>0x%08lx) by EFI %s\n", flags, cur_flags, call); arch_efi_restore_flags(flags); } /* * According to section 7.1 of the UEFI spec, Runtime Services are not fully * reentrant, and there are particular combinations of calls that need to be * serialized. (source: UEFI Specification v2.4A) * * Table 31. Rules for Reentry Into Runtime Services * +------------------------------------+-------------------------------+ * | If previous call is busy in | Forbidden to call | * +------------------------------------+-------------------------------+ * | Any | SetVirtualAddressMap() | * +------------------------------------+-------------------------------+ * | ConvertPointer() | ConvertPointer() | * +------------------------------------+-------------------------------+ * | SetVariable() | ResetSystem() | * | UpdateCapsule() | | * | SetTime() | | * | SetWakeupTime() | | * | GetNextHighMonotonicCount() | | * +------------------------------------+-------------------------------+ * | GetVariable() | GetVariable() | * | GetNextVariableName() | GetNextVariableName() | * | SetVariable() | SetVariable() | * | QueryVariableInfo() | QueryVariableInfo() | * | UpdateCapsule() | UpdateCapsule() | * | QueryCapsuleCapabilities() | QueryCapsuleCapabilities() | * | GetNextHighMonotonicCount() | GetNextHighMonotonicCount() | * +------------------------------------+-------------------------------+ * | GetTime() | GetTime() | * | SetTime() | SetTime() | * | GetWakeupTime() | GetWakeupTime() | * | SetWakeupTime() | SetWakeupTime() | * +------------------------------------+-------------------------------+ * * Due to the fact that the EFI pstore may write to the variable store in * interrupt context, we need to use a lock for at least the groups that * contain SetVariable() and QueryVariableInfo(). That leaves little else, as * none of the remaining functions are actually ever called at runtime. * So let's just use a single lock to serialize all Runtime Services calls. */ static DEFINE_SEMAPHORE(efi_runtime_lock); /* * Expose the EFI runtime lock to the UV platform */ #ifdef CONFIG_X86_UV extern struct semaphore __efi_uv_runtime_lock __alias(efi_runtime_lock); #endif /* * Calls the appropriate efi_runtime_service() with the appropriate * arguments. * * Semantics followed by efi_call_rts() to understand efi_runtime_work: * 1. If argument was a pointer, recast it from void pointer to original * pointer type. * 2. If argument was a value, recast it from void pointer to original * pointer type and dereference it. */ static void efi_call_rts(struct work_struct *work) { void *arg1, *arg2, *arg3, *arg4, *arg5; efi_status_t status = EFI_NOT_FOUND; arg1 = efi_rts_work.arg1; arg2 = efi_rts_work.arg2; arg3 = efi_rts_work.arg3; arg4 = efi_rts_work.arg4; arg5 = efi_rts_work.arg5; switch (efi_rts_work.efi_rts_id) { case EFI_GET_TIME: status = efi_call_virt(get_time, (efi_time_t *)arg1, (efi_time_cap_t *)arg2); break; case EFI_SET_TIME: status = efi_call_virt(set_time, (efi_time_t *)arg1); break; case EFI_GET_WAKEUP_TIME: status = efi_call_virt(get_wakeup_time, (efi_bool_t *)arg1, (efi_bool_t *)arg2, (efi_time_t *)arg3); break; case EFI_SET_WAKEUP_TIME: status = efi_call_virt(set_wakeup_time, *(efi_bool_t *)arg1, (efi_time_t *)arg2); break; case EFI_GET_VARIABLE: status = efi_call_virt(get_variable, (efi_char16_t *)arg1, (efi_guid_t *)arg2, (u32 *)arg3, (unsigned long *)arg4, (void *)arg5); break; case EFI_GET_NEXT_VARIABLE: status = efi_call_virt(get_next_variable, (unsigned long *)arg1, (efi_char16_t *)arg2, (efi_guid_t *)arg3); break; case EFI_SET_VARIABLE: status = efi_call_virt(set_variable, (efi_char16_t *)arg1, (efi_guid_t *)arg2, *(u32 *)arg3, *(unsigned long *)arg4, (void *)arg5); break; case EFI_QUERY_VARIABLE_INFO: status = efi_call_virt(query_variable_info, *(u32 *)arg1, (u64 *)arg2, (u64 *)arg3, (u64 *)arg4); break; case EFI_GET_NEXT_HIGH_MONO_COUNT: status = efi_call_virt(get_next_high_mono_count, (u32 *)arg1); break; case EFI_UPDATE_CAPSULE: status = efi_call_virt(update_capsule, (efi_capsule_header_t **)arg1, *(unsigned long *)arg2, *(unsigned long *)arg3); break; case EFI_QUERY_CAPSULE_CAPS: status = efi_call_virt(query_capsule_caps, (efi_capsule_header_t **)arg1, *(unsigned long *)arg2, (u64 *)arg3, (int *)arg4); break; default: /* * Ideally, we should never reach here because a caller of this * function should have put the right efi_runtime_service() * function identifier into efi_rts_work->efi_rts_id */ pr_err("Requested executing invalid EFI Runtime Service.\n"); } efi_rts_work.status = status; complete(&efi_rts_work.efi_rts_comp); } static efi_status_t virt_efi_get_time(efi_time_t *tm, efi_time_cap_t *tc) { efi_status_t status; if (down_interruptible(&efi_runtime_lock)) return EFI_ABORTED; status = efi_queue_work(EFI_GET_TIME, tm, tc, NULL, NULL, NULL); up(&efi_runtime_lock); return status; } static efi_status_t virt_efi_set_time(efi_time_t *tm) { efi_status_t status; if (down_interruptible(&efi_runtime_lock)) return EFI_ABORTED; status = efi_queue_work(EFI_SET_TIME, tm, NULL, NULL, NULL, NULL); up(&efi_runtime_lock); return status; } static efi_status_t virt_efi_get_wakeup_time(efi_bool_t *enabled, efi_bool_t *pending, efi_time_t *tm) { efi_status_t status; if (down_interruptible(&efi_runtime_lock)) return EFI_ABORTED; status = efi_queue_work(EFI_GET_WAKEUP_TIME, enabled, pending, tm, NULL, NULL); up(&efi_runtime_lock); return status; } static efi_status_t virt_efi_set_wakeup_time(efi_bool_t enabled, efi_time_t *tm) { efi_status_t status; if (down_interruptible(&efi_runtime_lock)) return EFI_ABORTED; status = efi_queue_work(EFI_SET_WAKEUP_TIME, &enabled, tm, NULL, NULL, NULL); up(&efi_runtime_lock); return status; } static efi_status_t virt_efi_get_variable(efi_char16_t *name, efi_guid_t *vendor, u32 *attr, unsigned long *data_size, void *data) { efi_status_t status; if (down_interruptible(&efi_runtime_lock)) return EFI_ABORTED; status = efi_queue_work(EFI_GET_VARIABLE, name, vendor, attr, data_size, data); up(&efi_runtime_lock); return status; } static efi_status_t virt_efi_get_next_variable(unsigned long *name_size, efi_char16_t *name, efi_guid_t *vendor) { efi_status_t status; if (down_interruptible(&efi_runtime_lock)) return EFI_ABORTED; status = efi_queue_work(EFI_GET_NEXT_VARIABLE, name_size, name, vendor, NULL, NULL); up(&efi_runtime_lock); return status; } static efi_status_t virt_efi_set_variable(efi_char16_t *name, efi_guid_t *vendor, u32 attr, unsigned long data_size, void *data) { efi_status_t status; if (down_interruptible(&efi_runtime_lock)) return EFI_ABORTED; status = efi_queue_work(EFI_SET_VARIABLE, name, vendor, &attr, &data_size, data); up(&efi_runtime_lock); return status; } static efi_status_t virt_efi_set_variable_nonblocking(efi_char16_t *name, efi_guid_t *vendor, u32 attr, unsigned long data_size, void *data) { efi_status_t status; if (down_trylock(&efi_runtime_lock)) return EFI_NOT_READY; status = efi_call_virt(set_variable, name, vendor, attr, data_size, data); up(&efi_runtime_lock); return status; } static efi_status_t virt_efi_query_variable_info(u32 attr, u64 *storage_space, u64 *remaining_space, u64 *max_variable_size) { efi_status_t status; if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION) return EFI_UNSUPPORTED; if (down_interruptible(&efi_runtime_lock)) return EFI_ABORTED; status = efi_queue_work(EFI_QUERY_VARIABLE_INFO, &attr, storage_space, remaining_space, max_variable_size, NULL); up(&efi_runtime_lock); return status; } static efi_status_t virt_efi_query_variable_info_nonblocking(u32 attr, u64 *storage_space, u64 *remaining_space, u64 *max_variable_size) { efi_status_t status; if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION) return EFI_UNSUPPORTED; if (down_trylock(&efi_runtime_lock)) return EFI_NOT_READY; status = efi_call_virt(query_variable_info, attr, storage_space, remaining_space, max_variable_size); up(&efi_runtime_lock); return status; } static efi_status_t virt_efi_get_next_high_mono_count(u32 *count) { efi_status_t status; if (down_interruptible(&efi_runtime_lock)) return EFI_ABORTED; status = efi_queue_work(EFI_GET_NEXT_HIGH_MONO_COUNT, count, NULL, NULL, NULL, NULL); up(&efi_runtime_lock); return status; } static void virt_efi_reset_system(int reset_type, efi_status_t status, unsigned long data_size, efi_char16_t *data) { if (down_trylock(&efi_runtime_lock)) { pr_warn("failed to invoke the reset_system() runtime service:\n" "could not get exclusive access to the firmware\n"); return; } efi_rts_work.efi_rts_id = EFI_RESET_SYSTEM; __efi_call_virt(reset_system, reset_type, status, data_size, data); up(&efi_runtime_lock); } static efi_status_t virt_efi_update_capsule(efi_capsule_header_t **capsules, unsigned long count, unsigned long sg_list) { efi_status_t status; if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION) return EFI_UNSUPPORTED; if (down_interruptible(&efi_runtime_lock)) return EFI_ABORTED; status = efi_queue_work(EFI_UPDATE_CAPSULE, capsules, &count, &sg_list, NULL, NULL); up(&efi_runtime_lock); return status; } static efi_status_t virt_efi_query_capsule_caps(efi_capsule_header_t **capsules, unsigned long count, u64 *max_size, int *reset_type) { efi_status_t status; if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION) return EFI_UNSUPPORTED; if (down_interruptible(&efi_runtime_lock)) return EFI_ABORTED; status = efi_queue_work(EFI_QUERY_CAPSULE_CAPS, capsules, &count, max_size, reset_type, NULL); up(&efi_runtime_lock); return status; } void efi_native_runtime_setup(void) { efi.get_time = virt_efi_get_time; efi.set_time = virt_efi_set_time; efi.get_wakeup_time = virt_efi_get_wakeup_time; efi.set_wakeup_time = virt_efi_set_wakeup_time; efi.get_variable = virt_efi_get_variable; efi.get_next_variable = virt_efi_get_next_variable; efi.set_variable = virt_efi_set_variable; efi.set_variable_nonblocking = virt_efi_set_variable_nonblocking; efi.get_next_high_mono_count = virt_efi_get_next_high_mono_count; efi.reset_system = virt_efi_reset_system; efi.query_variable_info = virt_efi_query_variable_info; efi.query_variable_info_nonblocking = virt_efi_query_variable_info_nonblocking; efi.update_capsule = virt_efi_update_capsule; efi.query_capsule_caps = virt_efi_query_capsule_caps; }