On 1/12/20, Jari Ruusu jari.ruusu@gmail.com wrote:
Intel Software Developer's Manual, volume 3, chapter 9.11.6 says: "Note that the microcode update must be aligned on a 16-byte boundary and the size of the microcode update must be 1-KByte granular"
When early-load Intel microcode is loaded from initramfs, userspace tool 'iucode_tool' has already 16-byte aligned those microcode bits in that initramfs image. Image that was created something like this:
iucode_tool --write-earlyfw=FOO.cpio microcode-files...
However, when early-load Intel microcode is loaded from built-in firmware BLOB using CONFIG_EXTRA_FIRMWARE= kernel config option, that 16-byte alignment is not guaranteed.
Fix this by forcing all built-in firmware BLOBs to 16-byte alignment.
Backport of "Fix built-in early-load Intel microcode alignment" for linux-4.19 and older stable kernels.
Signed-off-by: Jari Ruusu jari.ruusu@gmail.com
--- a/firmware/Makefile +++ b/firmware/Makefile @@ -19,7 +19,7 @@ PROGBITS=$(if $(CONFIG_ARM),%,@)progbits; \ echo "/* Generated by firmware/Makefile */" > $@;\ echo " .section .rodata" >>$@;\ - echo " .p2align $${ASM_ALIGN}" >>$@;\ + echo " .p2align 4" >>$@;\ echo "_fw_$${FWSTR}_bin:" >>$@;\ echo " .incbin "$(2)"" >>$@;\ echo "_fw_end:" >>$@;\