diff options
Diffstat (limited to 'drivers/firmware/efi/runtime-wrappers.c')
| -rw-r--r-- | drivers/firmware/efi/runtime-wrappers.c | 590 |
1 files changed, 590 insertions, 0 deletions
diff --git a/drivers/firmware/efi/runtime-wrappers.c b/drivers/firmware/efi/runtime-wrappers.c new file mode 100644 index 0000000000..5d56bc40a7 --- /dev/null +++ b/drivers/firmware/efi/runtime-wrappers.c @@ -0,0 +1,590 @@ +// 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; + +/* + * 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); + +/* + * 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. + */ +static void 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; + + 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(); + + efi_rts_work.status = status; + complete(&efi_rts_work.efi_rts_comp); +} + +static efi_status_t __efi_queue_work(enum efi_rts_ids id, + union efi_rts_args *args) +{ + 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; + + if (!efi_enabled(EFI_RUNTIME_SERVICES)) { + pr_warn_once("EFI Runtime Services are disabled!\n"); + efi_rts_work.status = EFI_DEVICE_ERROR; + goto exit; + } + + 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)) + 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; + 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 +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; + + status = efi_call_virt_pointer(efi.runtime, 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(QUERY_VARIABLE_INFO, attr, storage_space, + remaining_space, max_variable_size); + up(&efi_runtime_lock); + return status; +} + +static efi_status_t +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; + + status = efi_call_virt_pointer(efi.runtime, 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(GET_NEXT_HIGH_MONO_COUNT, count); + 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; + } + + 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(); + + 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 |