efi: Add 'capsule' update support

The EFI capsule mechanism allows data blobs to be passed to the EFI
firmware. A common use case is performing firmware updates. This patch
just introduces the main infrastructure for interacting with the
firmware, and a driver that allows users to upload capsules will come
in a later patch.

Once a capsule has been passed to the firmware, the next reboot must
be performed using the ResetSystem() EFI runtime service, which may
involve overriding the reboot type specified by reboot=. This ensures
the reset value returned by QueryCapsuleCapabilities() is used to
reset the system, which is required for the capsule to be processed.
efi_capsule_pending() is provided for this purpose.

At the moment we only allow a single capsule blob to be sent to the
firmware despite the fact that UpdateCapsule() takes a 'CapsuleCount'
parameter. This simplifies the API and shouldn't result in any
downside since it is still possible to send multiple capsules by
repeatedly calling UpdateCapsule().

Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Bryan O'Donoghue <pure.logic@nexus-software.ie>
Cc: Kweh Hock Leong <hock.leong.kweh@intel.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Peter Jones <pjones@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: joeyli <jlee@suse.com>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1461614832-17633-28-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 14 insertions, 0 deletions

diff --git a/include/linux/efi.h b/include/linux/efi.h
index ca47481885c4..a3b4c1ec38c0 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -125,6 +125,13 @@ typedef struct {
 } efi_capsule_header_t;
 
 /*
+ * EFI capsule flags
+ */
+#define EFI_CAPSULE_PERSIST_ACROSS_RESET	0x00010000
+#define EFI_CAPSULE_POPULATE_SYSTEM_TABLE	0x00020000
+#define EFI_CAPSULE_INITIATE_RESET		0x00040000
+
+/*
  * Allocation types for calls to boottime->allocate_pages.
  */
 #define EFI_ALLOCATE_ANY_PAGES		0
@@ -1370,6 +1377,13 @@ int efivars_sysfs_init(void);
 #define EFIVARS_DATA_SIZE_MAX 1024
 
 #endif /* CONFIG_EFI_VARS */
+extern bool efi_capsule_pending(int *reset_type);
+
+extern int efi_capsule_supported(efi_guid_t guid, u32 flags,
+				 size_t size, int *reset);
+
+extern int efi_capsule_update(efi_capsule_header_t *capsule,
+			      struct page **pages);
 
 #ifdef CONFIG_EFI_RUNTIME_MAP
 int efi_runtime_map_init(struct kobject *);