This introduces a new runtime wrapper for the QueryVariableInfo() UEFI
Runtime Service, which gives up immediately rather than spins on failure
to grab the efi_runtime spinlock.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
---
drivers/firmware/efi/runtime-wrappers.c | 22 ++++++++++++++++++++
include/linux/efi.h | 1 +
2 files changed, 23 insertions(+)
diff --git a/drivers/firmware/efi/runtime-wrappers.c b/drivers/firmware/efi/runtime-wrappers.c
index 228bbf910461..e9f2867f0d91 100644
--- a/drivers/firmware/efi/runtime-wrappers.c
+++ b/drivers/firmware/efi/runtime-wrappers.c
@@ -230,6 +230,27 @@ static efi_status_t virt_efi_query_variable_info(u32 attr,
return status;
}
+static efi_status_t
+virt_efi_query_variable_info_nonblocking(u32 attr,
+ u64 *storage_space,
+ u64 *remaining_space,
+ u64 *max_variable_size)
+{
+ unsigned long flags;
+ efi_status_t status;
+
+ if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION)
+ return EFI_UNSUPPORTED;
+
+ if (!spin_trylock_irqsave(&efi_runtime_lock, flags))
+ return EFI_NOT_READY;
+
+ status = efi_call_virt(query_variable_info, attr, storage_space,
+ remaining_space, max_variable_size);
+ spin_unlock_irqrestore(&efi_runtime_lock, flags);
+ return status;
+}
+
static efi_status_t virt_efi_get_next_high_mono_count(u32 *count)
{
unsigned long flags;
@@ -300,6 +321,7 @@ void efi_native_runtime_setup(void)
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;
}
diff --git a/include/linux/efi.h b/include/linux/efi.h
index 8706e0aabedc..ad1e177ba48e 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -849,6 +849,7 @@ extern struct efi {
efi_set_variable_t *set_variable;
efi_set_variable_t *set_variable_nonblocking;
efi_query_variable_info_t *query_variable_info;
+ efi_query_variable_info_t *query_variable_info_nonblocking;
efi_update_capsule_t *update_capsule;
efi_query_capsule_caps_t *query_capsule_caps;
efi_get_next_high_mono_count_t *get_next_high_mono_count;
--
1.9.1
--
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