diff options
Diffstat (limited to 'drivers/firmware/efi/runtime-wrappers.c')
| -rw-r--r-- | drivers/firmware/efi/runtime-wrappers.c | 480 |
1 files changed, 480 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..1fba4e09c --- /dev/null +++ b/drivers/firmware/efi/runtime-wrappers.c @@ -0,0 +1,480 @@ +// 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.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"); \ + 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); \ + 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; +} |