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From: Matt Fleming <matt-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>
To: Daniel Baluta <daniel.baluta-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Cc: linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	stefan.stanacar-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org,
	octavian.purdila-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	matthew.k.gumbel-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org,
	mohamed.abbas-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org,
	constantin.musca-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org
Subject: Re: [PATCH v2] efi: Introduce EFI bootloader control driver
Date: Fri, 18 Mar 2016 16:15:05 +0000	[thread overview]
Message-ID: <20160318161505.GU2619@codeblueprint.co.uk> (raw)
In-Reply-To: <1458295910-26557-1-git-send-email-daniel.baluta-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>

On Fri, 18 Mar, at 12:11:50PM, Daniel Baluta wrote:
> From: Matt Gumbel <matthew.k.gumbel-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
> 
> This driver intercepts system reboot requests and populates the
> LoaderEntryOneShot EFI variable with the user-supplied reboot
> argument. EFI bootloaders such as Gummiboot will consume this
> variable and use it to control which OS is booted next.
> 
> We use this with Android where reboot() tells the kernel that
> we want to boot into recovery or other non-default OS environment.
> 
> It is the bootloader's job to guard against this variable being
> uninitialzed or containing invalid data, and just boot normally
> if that is the case.
> 
> Signed-off-by: Matt Gumbel <matthew.k.gumbel-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
> Signed-off-by: Mohamed Abbas <mohamed.abbas-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
> Signed-off-by: Constantin Musca <constantin.musca-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
> Signed-off-by: Daniel Baluta <daniel.baluta-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
> ---
> Changes since v1:
> 	* updated Makefile after changing source name from efibc.c -> efi-bc.c
> 	to comply with naming rules in drivers/firmware/efi/
> 
>  drivers/firmware/efi/Kconfig  |  11 ++
>  drivers/firmware/efi/Makefile |   1 +
>  drivers/firmware/efi/efi-bc.c | 251 ++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 263 insertions(+)
>  create mode 100644 drivers/firmware/efi/efi-bc.c

Why does this require a driver? Why is it not possible to solve this
problem by creating the variable in userspace before invoking
reboot(2)?

WARNING: multiple messages have this Message-ID (diff)
From: Matt Fleming <matt@codeblueprint.co.uk>
To: Daniel Baluta <daniel.baluta@intel.com>
Cc: linux-efi@vger.kernel.org, stefan.stanacar@intel.com,
	octavian.purdila@intel.com, linux-kernel@vger.kernel.org,
	matthew.k.gumbel@intel.com, mohamed.abbas@intel.com,
	constantin.musca@intel.com
Subject: Re: [PATCH v2] efi: Introduce EFI bootloader control driver
Date: Fri, 18 Mar 2016 16:15:05 +0000	[thread overview]
Message-ID: <20160318161505.GU2619@codeblueprint.co.uk> (raw)
In-Reply-To: <1458295910-26557-1-git-send-email-daniel.baluta@intel.com>

On Fri, 18 Mar, at 12:11:50PM, Daniel Baluta wrote:
> From: Matt Gumbel <matthew.k.gumbel@intel.com>
> 
> This driver intercepts system reboot requests and populates the
> LoaderEntryOneShot EFI variable with the user-supplied reboot
> argument. EFI bootloaders such as Gummiboot will consume this
> variable and use it to control which OS is booted next.
> 
> We use this with Android where reboot() tells the kernel that
> we want to boot into recovery or other non-default OS environment.
> 
> It is the bootloader's job to guard against this variable being
> uninitialzed or containing invalid data, and just boot normally
> if that is the case.
> 
> Signed-off-by: Matt Gumbel <matthew.k.gumbel@intel.com>
> Signed-off-by: Mohamed Abbas <mohamed.abbas@intel.com>
> Signed-off-by: Constantin Musca <constantin.musca@intel.com>
> Signed-off-by: Daniel Baluta <daniel.baluta@intel.com>
> ---
> Changes since v1:
> 	* updated Makefile after changing source name from efibc.c -> efi-bc.c
> 	to comply with naming rules in drivers/firmware/efi/
> 
>  drivers/firmware/efi/Kconfig  |  11 ++
>  drivers/firmware/efi/Makefile |   1 +
>  drivers/firmware/efi/efi-bc.c | 251 ++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 263 insertions(+)
>  create mode 100644 drivers/firmware/efi/efi-bc.c

Why does this require a driver? Why is it not possible to solve this
problem by creating the variable in userspace before invoking
reboot(2)?

  parent reply	other threads:[~2016-03-18 16:15 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-03-18 10:11 [PATCH v2] efi: Introduce EFI bootloader control driver Daniel Baluta
2016-03-18 10:11 ` Daniel Baluta
     [not found] ` <1458295910-26557-1-git-send-email-daniel.baluta-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
2016-03-18 11:22   ` kbuild test robot
2016-03-18 11:22     ` kbuild test robot
2016-03-18 12:46   ` kbuild test robot
2016-03-18 12:46     ` kbuild test robot
2016-03-18 16:15   ` Matt Fleming [this message]
2016-03-18 16:15     ` Matt Fleming
     [not found]     ` <20160318161505.GU2619-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>
2016-03-18 19:18       ` Stanacar, Stefan
2016-03-18 19:18         ` Stanacar, Stefan
2016-03-24 14:47         ` Matt Fleming
     [not found]           ` <20160324144741.GA4328-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>
2016-03-24 16:15             ` Stanacar, Stefan
2016-03-24 16:15               ` Stanacar, Stefan
     [not found]               ` <1458836156.14677.9.camel-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
2016-03-29 12:53                 ` Matt Fleming
2016-03-29 12:53                   ` Matt Fleming

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