[PATCH 2/3] x86/EFI: Explain buildid.ihex

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

This is an awful lot of magic to only be explained in a commit message.

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
CC: Jan Beulich <JBeulich@xxxxxxxx>
CC: Roger Pau Monné <roger.pau@xxxxxxxxxx>
CC: Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>
CC: Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx>
CC: Daniel P. Smith <dpsmith@xxxxxxxxxxxxxxxxxxxx>
---
 xen/arch/x86/efi/Makefile | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/xen/arch/x86/efi/Makefile b/xen/arch/x86/efi/Makefile
index c6678652fc98..3e88f552d20b 100644
--- a/xen/arch/x86/efi/Makefile
+++ b/xen/arch/x86/efi/Makefile
@@ -6,6 +6,8 @@ cmd_objcopy_o_ihex = $(OBJCOPY) -I ihex -O binary $< $@
 $(obj)/%.o: $(src)/%.ihex FORCE
        $(call if_changed,objcopy_o_ihex)
 
+# buildid.ihex is an empty COFF object.  It exists for the side effect it has
+# when linking into xen.efi, causing --build-id to attach a .buildid section.
 $(obj)/boot.init.o: $(obj)/buildid.o
 
 $(call cc-option-add,cflags-stack-boundary,CC,-mpreferred-stack-boundary=4)
-- 
2.39.5