EFI v2.4 and later may provide for a EFI_RNG_PROTOCOL, which can be called from the EFI stubs to seed the kernel entropy pool. So far, this feature has only been implemented on arm/arm64. This series makes the relevant EFI libstub code arch-independent and enables the feature also on x86. Please note that this feature only works if Linux is booted as an EFI stub, and that the EFI-provided randomness is not credited as entropy unless RANDOM_TRUST_BOOTLOADER is set. Thanks to Ard Biesheuvel for his hints on how to test the EFI_RNG_PROTOCOL from the UEFI shell ( RngTest-X64.efi ), and especially to Mario Limonciello: he gave me highly useful hints on the implementation of the EFI_RNG_PROTOCOL which ultimately helped me to determine why the earlier RFC patch did not work out as expected. The patches are also available in the Git repository at: https://git.kernel.org/pub/scm/linux/kernel/git/brodo/linux.git/ random Dominik Brodowski (2): efi/random: use arch-independent efi_call_proto() x86: efi/random: Invoke EFI_RNG_PROTOCOL to seed the UEFI RNG table arch/x86/boot/compressed/eboot.c | 3 +++ drivers/firmware/efi/libstub/Makefile | 5 +++-- drivers/firmware/efi/libstub/efistub.h | 2 -- drivers/firmware/efi/libstub/random.c | 21 ++++++++++++++++----- include/linux/efi.h | 2 ++ 5 files changed, 24 insertions(+), 9 deletions(-) -- 2.24.0
