Date:   Tue, 5 Jun 2018 22:46:23 +0200
From:   "Luis R. Rodriguez" <mcgrof@...nel.org>
To:     Hans de Goede <hdegoede@...hat.com>,
        Mimi Zohar <zohar@...ux.vnet.ibm.com>
Cc:     Ard Biesheuvel <ard.biesheuvel@...aro.org>,
        "Luis R . Rodriguez" <mcgrof@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        "H . Peter Anvin" <hpa@...or.com>, Peter Jones <pjones@...hat.com>,
        Dave Olsthoorn <dave@...aar.me>,
        Will Deacon <will.deacon@....com>,
        Andy Lutomirski <luto@...nel.org>,
        Matt Fleming <matt@...eblueprint.co.uk>,
        David Howells <dhowells@...hat.com>,
        Josh Triplett <josh@...htriplett.org>,
        dmitry.torokhov@...il.com, mfuzzey@...keon.com,
        Kalle Valo <kvalo@...eaurora.org>,
        Arend Van Spriel <arend.vanspriel@...adcom.com>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        nbroeking@...com, bjorn.andersson@...aro.org,
        Torsten Duwe <duwe@...e.de>, Kees Cook <keescook@...omium.org>,
        x86@...nel.org, linux-efi@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v6 0/5] efi/firmware/platform-x86: Add EFI embedded fw
 support

On Fri, Jun 01, 2018 at 02:53:25PM +0200, Hans de Goede wrote:
> Hi All,
> 
> Here is v6 of my patch-set to add support for EFI embedded fw to the kernel.
> 
> This patch-set applies on top of the "[PATCH v7 00/14] firmware_loader
> changes for v4.18" series from mcgrof.
> 
> It now also depends on the series from Andy Lutomirski which allow using the
> sha256 code in a standalone manner. Andy what is the status of those?
> 
> Changes since v5:
> -Rework code to remove casts from if (prefix == mem) comparison
> -Use SHA256 hashes instead of crc32 sums

Nice! I see no updates on this progress, but it would seem this
may then mean this cannot be merged until the release after?

> -Add new READING_FIRMWARE_EFI_EMBEDDED read_file_id and use it
> -Call security_kernel_read_file(NULL, READING_FIRMWARE_EFI_EMBEDDED)
>  to check if this is allowed before looking at EFI embedded fw

There's a discussion over having security_kernel_read_file(NULL,
READING_WHATEVER) become another LSM hook. So your series would conflict with
that at the moment.

So yet another piece of code which this series depends on.

> -Document why we are not using the PI Firmware Volume protocol
> 
> For reference I've included the coverletter from v4 (which includes
> previous covverletters) below.
> 
> Regards,
> 
> Hans
> 
> 
> Previous coverletter:
> 
> Here is v5 of my patch-set to add support for EFI embedded fw to the kernel.
> 
> Changes since v4:
> -Rename the EFI_BOOT_SERVICES flag to EFI_PRESERVE_BS_REGIONS
> 
> So I think this patch-set is getting close to ready for merging, which
> brings us to the question of how to merge this, I think that patches 1
> and 2 should probably both be merged through the same tree. Then an
> unmutable branch should be created on that tree, merged into the
> platform/x86 tree and then the last 3 patches can be merged through
> that tree.
> 
> Ard has already indicated he is fine with the EFI bits going upstream
> through another tree, so perhaps patches 1-2 can be merged through the
> firmware-loader-tree and then do an unmutable branch on the
> firmware-loader-tree for the platform/x86 tree to merge?
> 
> I don't think taking all 5 through 1 tree is a good idea because of
> the file rename under platform/x86.
> 
> 
> For the record here are the cover letters of the previous versions:
> 
> Changes since v3:
> -Drop note in docs about EFI_FIRMWARE_VOLUME_PROTOCOL, it is not part of
>  UEFI proper, so the EFI maintainers don't want us referring people to it
> -Use new EFI_BOOT_SERVICES flag
> -Put the new fw_get_efi_embedded_fw() function in its own fallback_efi.c
>  file which only gets built when EFI_EMBEDDED_FIRMWARE is selected
> -Define an empty stub for fw_get_efi_embedded_fw() in fallback.h hwen
>  EFI_EMBEDDED_FIRMWARE is not selected, to avoid the need for #ifdefs
>  in firmware_loader/main.c
> -Properly call security_kernel_post_read_file() on the firmware returned
>  by efi_get_embedded_fw() to make sure that we are allowed to use it
> 
> The 3 most prominent changes in v2 are:
> 
> 1) Add documentation describing the EFI embedded firmware mechanism to:
>    Documentation/driver-api/firmware/request_firmware.rst
> 
> 2) Instead of having a single dmi_system_id array with its driver_data
>    members pointing to efi_embedded_fw_desc structs, have the drivers which
>    need EFI embedded-fw support export a dmi_system_id array and register
>    that with the EFI embedded-fw code
> 
>    This series also includes the first driver to use this, in the form of
>    the touchscreen_dmi code (formerly silead_dmi) from drivers/platfrom/x86
> 
> 3) As discussed during the review of v1 we want to make the firmware_loader
>    code fallback to EFI embedded-fw optional.  Rather the adding yet another
>    firmware_request_foo variant for this, with the risk of later also needing
>    firmware_request_foo_nowait, etc. variants I've decided to make the code
>    check if the device has a "efi-embedded-firmware" device-property bool set.
> 
>    This also seemed better because the same driver may want to use the
>    fallback on some systems, but not on others since e.g. not all (x86)
>    systems with a silead touchscreen have their touchscreen firmware embedded
>    in their EFI.
> 
>    Note that (as discussed) when the EFI fallback path is requested, the
>    usermodehelper fallback path is skipped.
> 
> Here is the full changelog of patch 2/5 which is where most of the changes are:
> 
> Changes in v2:
> -Rebased on driver-core/driver-core-next
> -Add documentation describing the EFI embedded firmware mechanism to:
>  Documentation/driver-api/firmware/request_firmware.rst
> -Add a new EFI_EMBEDDED_FIRMWARE Kconfig bool and only build the embedded
>  fw support if this is set. This is an invisible option which should be
>  selected by drivers which need this
> -Remove the efi_embedded_fw_desc and dmi_system_id-s for known devices
>  from the efi-embedded-fw code, instead drivers using this are expected to
>  export a dmi_system_id array, with each entries' driver_data pointing to a
>  efi_embedded_fw_desc struct and register this with the efi-embedded-fw code
> -Use kmemdup to make a copy instead of efi_mem_reserve()-ing the firmware,
>  this avoids us messing with the EFI memmap and avoids the need to make
>  changes to efi_mem_desc_lookup()
> -Make the firmware-loader code only fallback to efi_get_embedded_fw() if the
>  passed in device has the "efi-embedded-firmware" device-property bool set
> -Skip usermodehelper fallback when "efi-embedded-firmware" device-property
>  is set
> 
> Patches 3-5 are new and implement using the EFI embedded-fw mechanism for
> Silead gslXXXX and Chipone icn8505 touchscreens on x86 devices.
> 
> 

-- 
Do not panic

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