x86/kprobes: Fix crash when probing CS CALL instructionsgrafted

When using eBPF to probe CS CALL instructions within a function,
a crash can be triggered.

The eBPF tool probes offset 257 of the __hrtimer_run_queues()
function:

<__hrtimer_run_queues+249>:  nopl   0x0(%rax,%rax,1)
<__hrtimer_run_queues+254>:  mov    %r14,%rdi
<__hrtimer_run_queues+257>:  cs call <__x86_indirect_thunk_r12>
<__hrtimer_run_queues+263>:  mov    %eax,%r12d
<__hrtimer_run_queues+266>:  xchg   %ax,%ax
<__hrtimer_run_queues+268>:  mov    %r13,%rdi

Which triggers this crash:

  BUG: unable to handle page fault for address: 00000000000f41c9
  #PF: supervisor write access in kernel mode
  #PF: error_code(0x0002) - not-present page
  PGD 0 P4D 0
  Oops: 0002 [#1] SMP NOPTI
  CPU: 1 PID: 0 Comm: swapper/1 Kdump: loaded Tainted: P
  RIP: 0010:__hrtimer_run_queues+0x106/0x230

Note that __hrtimer_run_queues+0x106 is __hrtimer_run_queues+262, which is
at the 6th byte of the above CS CALL instruction. Since the CS CALL
instruction occupies 6 bytes, the exception occurred in the middle of that
call instruction.

The root cause is that when using eBPF tools to probe in the middle of a
function, a kprobe with INT3 is used as the underlying implementation.

During single-step emulation of the original CALL instruction,
int3_emulate_call() assumes that the probed CALL instruction is 5 bytes
long. However, the actual CS-prefixed CALL instruction occupies 6 bytes,
so it constructs an incorrect exception return address. When the CPU
returns from the kprobe handler, the next instruction to be executed is at
the address of the last byte of that CS CALL instruction. Coincidentally,
starting from that address, the CPU fetches and decodes a completely
different instruction, which ultimately triggers a kernel crash.

Fix the issue by using the actual instruction length obtained from
the instruction decoder when constructing the exception return
address, rather than relying on the hardcoded CALL_INSN_SIZE macro.

[ mingo: Refined the changelog ]

Fixes: 6256e668b7af ("x86/kprobes: Use int3 instead of debug trap for single-step")
Suggested-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Jinke Han <jinkehan@didiglobal.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Borislav Petkov <bp@alien8.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://patch.msgid.link/20260908073742.GA10517@didi-ThinkCentre-M920t-N000

1 files changed, 654 insertions, 0 deletions

diff --git a/drivers/firmware/efi/runtime-wrappers.c b/drivers/firmware/efi/runtime-wrappers.c
new file mode 100644
index 000000000..2344b9d1e
--- /dev/null
+++ b/drivers/firmware/efi/runtime-wrappers.c
@@ -0,0 +1,654 @@
+// 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. <ard.biesheuvel@linaro.org>
+ *
+ * Split off from arch/x86/platform/efi/efi.c
+ *
+ * Copyright (C) 1999 VA Linux Systems
+ * Copyright (C) 1999 Walt Drummond <drummond@valinux.com>
+ * 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 <linux/bug.h>
+#include <linux/efi.h>
+#include <linux/irqflags.h>
+#include <linux/mutex.h>
+#include <linux/semaphore.h>
+#include <linux/stringify.h>
+#include <linux/workqueue.h>
+#include <linux/completion.h>
+
+#include <asm/efi.h>
+
+/*
+ * Wrap around the new efi_call_virt_generic() macros so that the
+ * code doesn't get too cluttered:
+ */
+#define efi_call_virt(f, args...)   \
+	arch_efi_call_virt(efi.runtime, f, args)
+
+union efi_rts_args {
+	struct {
+		efi_time_t 	*time;
+		efi_time_cap_t	*capabilities;
+	} GET_TIME;
+
+	struct {
+		efi_time_t	*time;
+	} SET_TIME;
+
+	struct {
+		efi_bool_t	*enabled;
+		efi_bool_t	*pending;
+		efi_time_t	*time;
+	} GET_WAKEUP_TIME;
+
+	struct {
+		efi_bool_t	enable;
+		efi_time_t	*time;
+	} SET_WAKEUP_TIME;
+
+	struct {
+		efi_char16_t	*name;
+		efi_guid_t	*vendor;
+		u32		*attr;
+		unsigned long	*data_size;
+		void		*data;
+	} GET_VARIABLE;
+
+	struct {
+		unsigned long	*name_size;
+		efi_char16_t	*name;
+		efi_guid_t 	*vendor;
+	} GET_NEXT_VARIABLE;
+
+	struct {
+		efi_char16_t	*name;
+		efi_guid_t	*vendor;
+		u32		attr;
+		unsigned long	data_size;
+		void		*data;
+	} SET_VARIABLE;
+
+	struct {
+		u32		attr;
+		u64		*storage_space;
+		u64		*remaining_space;
+		u64		*max_variable_size;
+	} QUERY_VARIABLE_INFO;
+
+	struct {
+		u32		*high_count;
+	} GET_NEXT_HIGH_MONO_COUNT;
+
+	struct {
+		efi_capsule_header_t **capsules;
+		unsigned long	count;
+		unsigned long	sg_list;
+	} UPDATE_CAPSULE;
+
+	struct {
+		efi_capsule_header_t **capsules;
+		unsigned long	count;
+		u64		*max_size;
+		int		*reset_type;
+	} QUERY_CAPSULE_CAPS;
+
+	struct {
+		efi_status_t	(__efiapi *acpi_prm_handler)(u64, void *);
+		u64		param_buffer_addr;
+		void		*context;
+	} ACPI_PRM_HANDLER;
+};
+
+struct efi_runtime_work efi_rts_work;
+
+/*
+ * Upper bound on how long we wait for a single EFI runtime service
+ * call to finish before declaring firmware wedged. Chosen to be longer
+ * than any plausible legitimate call (including UpdateCapsule on slow
+ * SPI-NOR) while still bounding userspace wait time.
+ */
+#define EFI_RTS_TIMEOUT		(120 * HZ)
+
+/*
+ * efi_queue_work:	Queue EFI runtime service call and wait for completion
+ * @_rts:		EFI runtime service function identifier
+ * @_args:		Arguments to pass to the EFI runtime service
+ *
+ * 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, _args...)					\
+	__efi_queue_work(EFI_ ## _rts,					\
+			 &(union efi_rts_args){ ._rts = { _args }})
+
+#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 void *caller)
+{
+	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 call from %pS\n",
+			   flags, cur_flags, caller ?: __builtin_return_address(0));
+	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, 1);
+
+static struct task_struct *efi_runtime_lock_owner __used;
+
+/*
+ * 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
+
+/*
+ * Park a worker that must never run efi_rts_wq again: EFI runtime services
+ * have been disabled and its efi_rts_work is abandoned. Loop in schedule()
+ * so a spurious wakeup cannot resume it.
+ */
+void __noreturn efi_rts_park_worker(void)
+{
+	for (;;) {
+		set_current_state(TASK_IDLE);
+		schedule();
+	}
+}
+
+/*
+ * Calls the appropriate efi_runtime_service() with the appropriate
+ * arguments.
+ */
+static void __nocfi efi_call_rts(struct work_struct *work)
+{
+	const union efi_rts_args *args = efi_rts_work.args;
+	efi_status_t status = EFI_NOT_FOUND;
+	unsigned long flags;
+
+	if (!efi_enabled(EFI_RUNTIME_SERVICES))
+		efi_rts_park_worker();
+
+	efi_runtime_lock_owner = current;
+
+	arch_efi_call_virt_setup();
+	flags = efi_call_virt_save_flags();
+
+	switch (efi_rts_work.efi_rts_id) {
+	case EFI_GET_TIME:
+		status = efi_call_virt(get_time,
+				       args->GET_TIME.time,
+				       args->GET_TIME.capabilities);
+		break;
+	case EFI_SET_TIME:
+		status = efi_call_virt(set_time,
+				       args->SET_TIME.time);
+		break;
+	case EFI_GET_WAKEUP_TIME:
+		status = efi_call_virt(get_wakeup_time,
+				       args->GET_WAKEUP_TIME.enabled,
+				       args->GET_WAKEUP_TIME.pending,
+				       args->GET_WAKEUP_TIME.time);
+		break;
+	case EFI_SET_WAKEUP_TIME:
+		status = efi_call_virt(set_wakeup_time,
+				       args->SET_WAKEUP_TIME.enable,
+				       args->SET_WAKEUP_TIME.time);
+		break;
+	case EFI_GET_VARIABLE:
+		status = efi_call_virt(get_variable,
+				       args->GET_VARIABLE.name,
+				       args->GET_VARIABLE.vendor,
+				       args->GET_VARIABLE.attr,
+				       args->GET_VARIABLE.data_size,
+				       args->GET_VARIABLE.data);
+		break;
+	case EFI_GET_NEXT_VARIABLE:
+		status = efi_call_virt(get_next_variable,
+				       args->GET_NEXT_VARIABLE.name_size,
+				       args->GET_NEXT_VARIABLE.name,
+				       args->GET_NEXT_VARIABLE.vendor);
+		break;
+	case EFI_SET_VARIABLE:
+		status = efi_call_virt(set_variable,
+				       args->SET_VARIABLE.name,
+				       args->SET_VARIABLE.vendor,
+				       args->SET_VARIABLE.attr,
+				       args->SET_VARIABLE.data_size,
+				       args->SET_VARIABLE.data);
+		break;
+	case EFI_QUERY_VARIABLE_INFO:
+		status = efi_call_virt(query_variable_info,
+				       args->QUERY_VARIABLE_INFO.attr,
+				       args->QUERY_VARIABLE_INFO.storage_space,
+				       args->QUERY_VARIABLE_INFO.remaining_space,
+				       args->QUERY_VARIABLE_INFO.max_variable_size);
+		break;
+	case EFI_GET_NEXT_HIGH_MONO_COUNT:
+		status = efi_call_virt(get_next_high_mono_count,
+				       args->GET_NEXT_HIGH_MONO_COUNT.high_count);
+		break;
+	case EFI_UPDATE_CAPSULE:
+		status = efi_call_virt(update_capsule,
+				       args->UPDATE_CAPSULE.capsules,
+				       args->UPDATE_CAPSULE.count,
+				       args->UPDATE_CAPSULE.sg_list);
+		break;
+	case EFI_QUERY_CAPSULE_CAPS:
+		status = efi_call_virt(query_capsule_caps,
+				       args->QUERY_CAPSULE_CAPS.capsules,
+				       args->QUERY_CAPSULE_CAPS.count,
+				       args->QUERY_CAPSULE_CAPS.max_size,
+				       args->QUERY_CAPSULE_CAPS.reset_type);
+		break;
+	case EFI_ACPI_PRM_HANDLER:
+#ifdef CONFIG_ACPI_PRMT
+		status = arch_efi_call_virt(args, ACPI_PRM_HANDLER.acpi_prm_handler,
+					    args->ACPI_PRM_HANDLER.param_buffer_addr,
+					    args->ACPI_PRM_HANDLER.context);
+		break;
+#endif
+	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_call_virt_check_flags(flags, efi_rts_work.caller);
+	arch_efi_call_virt_teardown();
+
+	if (!efi_enabled(EFI_RUNTIME_SERVICES))
+		efi_rts_park_worker();
+
+	efi_rts_work.status = status;
+	complete(&efi_rts_work.efi_rts_comp);
+	efi_runtime_lock_owner = NULL;
+}
+
+static efi_status_t __efi_queue_work(enum efi_rts_ids id,
+				     union efi_rts_args *args)
+{
+	if (!efi_enabled(EFI_RUNTIME_SERVICES)) {
+		pr_warn_once("EFI Runtime Services are disabled!\n");
+		return EFI_DEVICE_ERROR;
+	}
+
+	efi_rts_work.efi_rts_id = id;
+	efi_rts_work.args = args;
+	efi_rts_work.caller = __builtin_return_address(0);
+	efi_rts_work.status = EFI_ABORTED;
+
+	init_completion(&efi_rts_work.efi_rts_comp);
+	INIT_WORK(&efi_rts_work.work, efi_call_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)) {
+		pr_err("Failed to queue work to efi_rts_wq.\n");
+		goto exit;
+	}
+
+	if (!wait_for_completion_timeout(&efi_rts_work.efi_rts_comp,
+					 EFI_RTS_TIMEOUT)) {
+		pr_err("EFI runtime service %d wedged in firmware; disabling EFI runtime services\n",
+		       id);
+		clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
+		return EFI_ABORTED;
+	}
+
+	WARN_ON_ONCE(efi_rts_work.status == EFI_ABORTED);
+exit:
+	efi_rts_work.efi_rts_id = EFI_NONE;
+	return efi_rts_work.status;
+}
+
+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(GET_TIME, tm, tc);
+	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(SET_TIME, tm);
+	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(GET_WAKEUP_TIME, enabled, pending, tm);
+	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(SET_WAKEUP_TIME, enabled, tm);
+	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(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(GET_NEXT_VARIABLE, name_size, name, vendor);
+	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(SET_VARIABLE, name, vendor, attr, data_size,
+				data);
+	up(&efi_runtime_lock);
+	return status;
+}
+
+static efi_status_t __nocfi
+virt_efi_set_variable_nb(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;
+
+	if (!efi_enabled(EFI_RUNTIME_SERVICES)) {
+		up(&efi_runtime_lock);
+		return EFI_DEVICE_ERROR;
+	}
+
+	efi_runtime_lock_owner = current;
+	status = efi_call_virt_pointer(efi.runtime, set_variable, name, vendor,
+				       attr, data_size, data);
+	efi_runtime_lock_owner = NULL;
+	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(QUERY_VARIABLE_INFO, attr, storage_space,
+				remaining_space, max_variable_size);
+	up(&efi_runtime_lock);
+	return status;
+}
+
+static efi_status_t __nocfi
+virt_efi_query_variable_info_nb(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;
+
+	if (!efi_enabled(EFI_RUNTIME_SERVICES)) {
+		up(&efi_runtime_lock);
+		return EFI_DEVICE_ERROR;
+	}
+
+	efi_runtime_lock_owner = current;
+	status = efi_call_virt_pointer(efi.runtime, query_variable_info, attr,
+				       storage_space, remaining_space,
+				       max_variable_size);
+	efi_runtime_lock_owner = NULL;
+	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(GET_NEXT_HIGH_MONO_COUNT, count);
+	up(&efi_runtime_lock);
+	return status;
+}
+
+static void __nocfi
+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;
+	}
+
+	if (!efi_enabled(EFI_RUNTIME_SERVICES)) {
+		pr_warn("EFI Runtime Services are disabled, not invoking reset_system()\n");
+		up(&efi_runtime_lock);
+		return;
+	}
+
+	efi_runtime_lock_owner = current;
+	arch_efi_call_virt_setup();
+	efi_rts_work.efi_rts_id = EFI_RESET_SYSTEM;
+	arch_efi_call_virt(efi.runtime, reset_system, reset_type, status,
+			   data_size, data);
+	arch_efi_call_virt_teardown();
+	efi_runtime_lock_owner = NULL;
+	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(UPDATE_CAPSULE, capsules, count, sg_list);
+	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(QUERY_CAPSULE_CAPS, capsules, count,
+				max_size, reset_type);
+	up(&efi_runtime_lock);
+	return status;
+}
+
+void __init 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_nb;
+	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_nb;
+	efi.update_capsule		    = virt_efi_update_capsule;
+	efi.query_capsule_caps		    = virt_efi_query_capsule_caps;
+}
+
+#ifdef CONFIG_ACPI_PRMT
+
+efi_status_t
+efi_call_acpi_prm_handler(efi_status_t (__efiapi *handler_addr)(u64, void *),
+			  u64 param_buffer_addr, void *context)
+{
+	efi_status_t status;
+
+	if (down_interruptible(&efi_runtime_lock))
+		return EFI_ABORTED;
+	status = efi_queue_work(ACPI_PRM_HANDLER, handler_addr,
+				param_buffer_addr, context);
+	up(&efi_runtime_lock);
+	return status;
+}
+
+#endif
+
+void efi_runtime_assert_lock_held(void)
+{
+	WARN_ON(efi_runtime_lock_owner != current);
+}