Re: [PATCH v6 0/5] efi/firmware/platform-x86: Add EFI embedded fw support

Luis R. Rodriguez
2018-06-05T20:46:23Z

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