Hi All, Here is v12 of my patch-set to add support for EFI embedded fw to the kernel. This version addresses Luis' review remarks for the test_firmware stuff and addresses some of Andy Lutomirski's remarks (while for some others I've explained why I've done things a certain way). It would be nice if we could at least get patches 1 and 2 merged for 5.6 (assuming Andy is ok with them now), then we can get the rest merged once 5.6-rc1 is out. As mentioned in the v11 cover letter, I've based this version on Ard's efi/next branch to avoid conflict with some changes already there. Regards, Hans --- Changes in v12: - Use memcmp to check the prefix in efi_check_for_embedded_firmwares() - Move the vmalloc (vmemdup) for the firmware copy owned by the firmare subsys from efi_get_embedded_fw() to firmware_fallback_platform(), so that it is is in the same subsys as the vfree which eventually frees it. - Use local / private firmware variable for the test instead of the global test_firmware variable and drop the mutex lock + unlock needed for accessing the global test_firmware variable Changes in v11: - Rebase on top of Ardb's efi/next - Drop a couple of empty lines which snuck into: "test_firmware: add support for firmware_request_platform" Changes in v10: - Rebase on top of 5.5-rc1 Changes in v9: - Add 2 new patches adding selftests - At least touchscreen_dmi.c uses the same dmi_table for its own private data and the fw_desc structs, putting the fw_desc struct first in the data driver_data points to so that the dmi_table can be shared with efi_check_for_embedded_firmwares(). But not all entries there have embedded-fw so in some cases the fw_desc is empty (zero-ed out). This can lead to a possible crash because fw_desc->length now is less then 8, so if the segment size is close enough to a multiple of the page_size, then the memcmp to check the prefix my segfault. Crashing the machine. v9 checks for and skips these empty fw_desc entries avoiding this. - Add static inline wrapper for firmware_request_platform() to firmware.h, for when CONFIG_FW_LOADER is not set Changes in v8: - Add pr_warn if there are mode then EFI_DEBUGFS_MAX_BLOBS boot service segments - Document how the EFI debugfs boot_service_code? files can be used to check for embedded firmware - Properly deal with the case of an EFI segment being smaller then the fw we are looking for - Log a warning when efi_get_embedded_fw get called while we did not (yet) check for embedded firmwares - Only build fallback_platform.c if CONFIG_EFI_EMBEDDED_FIRMWARE is defined, otherwise make firmware_fallback_platform() a static inline stub Changes in v7: - Split drivers/firmware/efi and drivers/base/firmware_loader changes into 2 patches - Use new, standalone, lib/crypto/sha256.c code - Address kdoc comments from Randy Dunlap - Add new FW_OPT_FALLBACK_PLATFORM flag and firmware_request_platform() _request_firmware() wrapper, as requested by Luis R. Rodriguez - Stop using "efi-embedded-firmware" device-property, now that drivers need to use the new firmware_request_platform() to enable fallback to a device fw copy embedded in the platform's main firmware, we no longer need a property on the device to trigger this behavior - Use security_kernel_load_data instead of calling security_kernel_read_file with a NULL file pointer argument - Move the docs to Documentation/driver-api/firmware/fallback-mechanisms.rst - Document the new firmware_request_platform() function in Documentation/driver-api/firmware/request_firmware.rst - Add 2 new patches for the silead and chipone-icn8505 touchscreen drivers to use the new firmware_request_platform() method - Rebased on top of 5.4-rc1 Changes in v6: -Rework code to remove casts from if (prefix == mem) comparison -Use SHA256 hashes instead of crc32 sums -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 -Document why we are not using the PI Firmware Volume protocol Changes in v5: -Rename the EFI_BOOT_SERVICES flag to EFI_PRESERVE_BS_REGIONS Changes in v4: -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 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
