From: Pingfan Liu <kernelfans@xxxxxxxxx>
commit 52416ffcf823ee11aa19792715664ab94757f111 upstream.
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@xxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Reviewed-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
Reviewed-by: Steve Wahl <steve.wahl@xxxxxxx>
Acked-by: Dave Young <dyoung@xxxxxxxxxx>
Link: https://lore.kernel.org/r/1596433788-3784-1-git-send-email-kernelfans@xxxxxxxxx
[Alyssa: fixed for LLVM_IAS=1 by adding -g to AFLAGS_REMOVE_*]
Signed-off-by: Alyssa Ross <hi@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/purgatory/Makefile | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
--- a/arch/x86/purgatory/Makefile
+++ b/arch/x86/purgatory/Makefile
@@ -27,7 +27,7 @@ KCOV_INSTRUMENT := n
# make up the standalone purgatory.ro
PURGATORY_CFLAGS_REMOVE := -mcmodel=kernel
-PURGATORY_CFLAGS := -mcmodel=large -ffreestanding -fno-zero-initialized-in-bss
+PURGATORY_CFLAGS := -mcmodel=large -ffreestanding -fno-zero-initialized-in-bss -g0
PURGATORY_CFLAGS += $(DISABLE_STACKLEAK_PLUGIN) -DDISABLE_BRANCH_PROFILING
# Default KBUILD_CFLAGS can have -pg option set when FTRACE is enabled. That
@@ -58,6 +58,9 @@ CFLAGS_sha256.o += $(PURGATORY_CFLAGS)
CFLAGS_REMOVE_string.o += $(PURGATORY_CFLAGS_REMOVE)
CFLAGS_string.o += $(PURGATORY_CFLAGS)
+AFLAGS_REMOVE_setup-x86_$(BITS).o += -g -Wa,-gdwarf-2
+AFLAGS_REMOVE_entry64.o += -g -Wa,-gdwarf-2
+
$(obj)/purgatory.ro: $(PURGATORY_OBJS) FORCE
$(call if_changed,ld)
