// 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...) \
efi_call_virt_pointer(efi.systab->runtime, f, args)
#define __efi_call_virt(f, args...) \
__efi_call_virt_pointer(efi.systab->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"); \
\
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_interruptible(&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;
}
