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Subject[tip:efi/core] efi/runtime-wrappers: Add a nonblocking version of QueryVariableInfo()
Commit-ID:  d3cac1f83c631b9fe5edaebcba49f6989bfff089
Gitweb: http://git.kernel.org/tip/d3cac1f83c631b9fe5edaebcba49f6989bfff089
Author: Ard Biesheuvel <ard.biesheuvel@linaro.org>
AuthorDate: Mon, 1 Feb 2016 22:06:57 +0000
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Wed, 3 Feb 2016 11:31:03 +0100

efi/runtime-wrappers: Add a nonblocking version of QueryVariableInfo()

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.

This is required in the non-blocking path of the efi-pstore
code.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1454364428-494-4-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
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 228bbf9..e9f2867 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 8706e0a..ad1e177 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;
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