linux/drivers/firmware/efi/reboot.c
Matt Fleming f0133f3c5b 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>
2016-04-28 11:34:03 +02:00

67 lines
1.4 KiB
C

/*
* Copyright (C) 2014 Intel Corporation; author Matt Fleming
* Copyright (c) 2014 Red Hat, Inc., Mark Salter <msalter@redhat.com>
*/
#include <linux/efi.h>
#include <linux/reboot.h>
int efi_reboot_quirk_mode = -1;
void efi_reboot(enum reboot_mode reboot_mode, const char *__unused)
{
const char *str[] = { "cold", "warm", "shutdown", "platform" };
int efi_mode, cap_reset_mode;
if (!efi_enabled(EFI_RUNTIME_SERVICES))
return;
switch (reboot_mode) {
case REBOOT_WARM:
case REBOOT_SOFT:
efi_mode = EFI_RESET_WARM;
break;
default:
efi_mode = EFI_RESET_COLD;
break;
}
/*
* If a quirk forced an EFI reset mode, always use that.
*/
if (efi_reboot_quirk_mode != -1)
efi_mode = efi_reboot_quirk_mode;
if (efi_capsule_pending(&cap_reset_mode)) {
if (efi_mode != cap_reset_mode)
printk(KERN_CRIT "efi: %s reset requested but pending "
"capsule update requires %s reset... Performing "
"%s reset.\n", str[efi_mode], str[cap_reset_mode],
str[cap_reset_mode]);
efi_mode = cap_reset_mode;
}
efi.reset_system(efi_mode, EFI_SUCCESS, 0, NULL);
}
bool __weak efi_poweroff_required(void)
{
return false;
}
static void efi_power_off(void)
{
efi.reset_system(EFI_RESET_SHUTDOWN, EFI_SUCCESS, 0, NULL);
}
static int __init efi_shutdown_init(void)
{
if (!efi_enabled(EFI_RUNTIME_SERVICES))
return -ENODEV;
if (efi_poweroff_required())
pm_power_off = efi_power_off;
return 0;
}
late_initcall(efi_shutdown_init);