[PATCH v4.14] x86/purgatory: Don't generate debug info for purgatory.ro

[Alyssa Ross <hi@alyssa.is>]

From: Pingfan Liu <kernelfans@gmail.com>

Purgatory.ro is a standalone binary that is not linked against the rest of
the kernel.  Its image is copied into an array that is linked to the
kernel, and from there kexec relocates it wherever it desires.

Unlike the debug info for vmlinux, which can be used for analyzing crash
such info is useless in purgatory.ro. And discarding them can save about
200K space.

 Original:
   259080  kexec-purgatory.o
 Stripped debug info:
    29152  kexec-purgatory.o

Signed-off-by: Pingfan Liu <kernelfans@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Steve Wahl <steve.wahl@hpe.com>
Acked-by: Dave Young <dyoung@redhat.com>
Link: https://lore.kernel.org/r/1596433788-3784-1-git-send-email-kernelfans@gmail.com
(cherry picked from commit 52416ffcf823ee11aa19792715664ab94757f111)
Signed-off-by: Alyssa Ross <hi@alyssa.is>
---
 arch/x86/purgatory/Makefile | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/x86/purgatory/Makefile b/arch/x86/purgatory/Makefile
index 2f15a2ac4209..2040ddb824c2 100644
--- a/arch/x86/purgatory/Makefile
+++ b/arch/x86/purgatory/Makefile
@@ -20,6 +20,9 @@ KBUILD_CFLAGS := -fno-strict-aliasing -Wall -Wstrict-prototypes -fno-zero-initia
 KBUILD_CFLAGS += -m$(BITS)
 KBUILD_CFLAGS += $(call cc-option,-fno-PIE)
 
+AFLAGS_REMOVE_setup-x86_$(BITS).o	+= -Wa,-gdwarf-2
+AFLAGS_REMOVE_entry64.o			+= -Wa,-gdwarf-2
+
 $(obj)/purgatory.ro: $(PURGATORY_OBJS) FORCE
 		$(call if_changed,ld)
 
-- 
2.37.1