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.
Signed-off-by: Jari Ruusu jari.ruusu@gmail.com
--- a/drivers/base/firmware_loader/builtin/Makefile +++ b/drivers/base/firmware_loader/builtin/Makefile @@ -17,7 +17,7 @@ filechk_fwbin = \ echo "/* Generated by $(src)/Makefile */" ;\ echo " .section .rodata" ;\ - echo " .p2align $(ASM_ALIGN)" ;\ + echo " .p2align 4" ;\ echo "_fw_$(FWSTR)_bin:" ;\ echo " .incbin "$(fwdir)/$(FWNAME)"" ;\ echo "_fw_end:" ;\