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