+From: Felix Fietkau <nbd@openwrt.org>
+
+use -ffunction-sections, -fdata-sections and --gc-sections
+
+In combination with kernel symbol export stripping this significantly reduces
+the kernel image size. Used on both ARM and MIPS architectures.
+
+Signed-off-by: Felix Fietkau <nbd@openwrt.org>
+Signed-off-by: Jonas Gorski <jogo@openwrt.org>
+Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
+---
+
--- a/arch/mips/Makefile
+++ b/arch/mips/Makefile
@@ -89,10 +89,14 @@ all-$(CONFIG_SYS_SUPPORTS_ZBOOT)+= vmlin
__stop_unwind_tab = .;
}
#endif
-@@ -162,24 +162,24 @@ SECTIONS
+@@ -158,14 +158,14 @@ SECTIONS
+ */
+ __vectors_start = .;
+ .vectors 0 : AT(__vectors_start) {
+- *(.vectors)
++ KEEP(*(.vectors))
+ }
+ . = __vectors_start + SIZEOF(.vectors);
+ __vectors_end = .;
+
+ __stubs_start = .;
+ .stubs 0x1000 : AT(__stubs_start) {
+- *(.stubs)
++ KEEP(*(.stubs))
+ }
+ . = __stubs_start + SIZEOF(.stubs);
+ __stubs_end = .;
+@@ -179,24 +179,24 @@ SECTIONS
}
.init.arch.info : {
__arch_info_begin = .;
.init.data : {
--- a/arch/arm/boot/compressed/Makefile
+++ b/arch/arm/boot/compressed/Makefile
-@@ -122,6 +122,7 @@ ifeq ($(CONFIG_FUNCTION_TRACER),y)
+@@ -123,6 +123,7 @@ ifeq ($(CONFIG_FUNCTION_TRACER),y)
ORIG_CFLAGS := $(KBUILD_CFLAGS)
KBUILD_CFLAGS = $(subst -pg, , $(ORIG_CFLAGS))
endif
+KBUILD_CFLAGS_KERNEL := $(patsubst -f%-sections,,$(KBUILD_CFLAGS_KERNEL))
ccflags-y := -fpic -mno-single-pic-base -fno-builtin -I$(obj)
- asflags-y := -Wa,-march=all -DZIMAGE
+ asflags-y := -DZIMAGE