diff options
Diffstat (limited to 'target/linux/generic/hack-5.4/220-gc_sections.patch')
| -rw-r--r-- | target/linux/generic/hack-5.4/220-gc_sections.patch | 192 |
1 files changed, 192 insertions, 0 deletions
diff --git a/target/linux/generic/hack-5.4/220-gc_sections.patch b/target/linux/generic/hack-5.4/220-gc_sections.patch new file mode 100644 index 0000000000..77422e821b --- /dev/null +++ b/target/linux/generic/hack-5.4/220-gc_sections.patch @@ -0,0 +1,192 @@ +From e3d8676f5722b7622685581e06e8f53e6138e3ab Mon Sep 17 00:00:00 2001 +From: Felix Fietkau <nbd@nbd.name> +Date: Sat, 15 Jul 2017 23:42:36 +0200 +Subject: 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@nbd.name> +Signed-off-by: Jonas Gorski <jogo@openwrt.org> +Signed-off-by: Gabor Juhos <juhosg@openwrt.org> +--- + Makefile | 10 +++---- + arch/arm/Kconfig | 1 + + arch/arm/boot/compressed/Makefile | 1 + + arch/arm/kernel/vmlinux.lds.S | 26 ++++++++-------- + arch/mips/Kconfig | 1 + + arch/mips/kernel/vmlinux.lds.S | 4 +-- + include/asm-generic/vmlinux.lds.h | 63 ++++++++++++++++++++------------------- + 7 files changed, 55 insertions(+), 51 deletions(-) + +--- a/Makefile ++++ b/Makefile +@@ -294,6 +294,11 @@ else + scripts/Kbuild.include: ; + include scripts/Kbuild.include + ++ifdef CONFIG_LD_DEAD_CODE_DATA_ELIMINATION ++KBUILD_CFLAGS_KERNEL += -ffunction-sections -fdata-sections ++LDFLAGS_vmlinux += --gc-sections ++endif ++ + # Read KERNELRELEASE from include/config/kernel.release (if it exists) + KERNELRELEASE = $(shell cat include/config/kernel.release 2> /dev/null) + KERNELVERSION = $(VERSION)$(if $(PATCHLEVEL),.$(PATCHLEVEL)$(if $(SUBLEVEL),.$(SUBLEVEL)))$(EXTRAVERSION) +@@ -782,11 +787,6 @@ ifdef CONFIG_DEBUG_SECTION_MISMATCH + KBUILD_CFLAGS += $(call cc-option, -fno-inline-functions-called-once) + endif + +-ifdef CONFIG_LD_DEAD_CODE_DATA_ELIMINATION +-KBUILD_CFLAGS_KERNEL += -ffunction-sections -fdata-sections +-LDFLAGS_vmlinux += --gc-sections +-endif +- + # arch Makefile may override CC so keep this after arch Makefile is included + NOSTDINC_FLAGS += -nostdinc -isystem $(shell $(CC) -print-file-name=include) + +--- a/arch/arm/Kconfig ++++ b/arch/arm/Kconfig +@@ -98,6 +98,7 @@ config ARM + select HAVE_UID16 + select HAVE_VIRT_CPU_ACCOUNTING_GEN + select IRQ_FORCED_THREADING ++ select HAVE_LD_DEAD_CODE_DATA_ELIMINATION + select MODULES_USE_ELF_REL + select NEED_DMA_MAP_STATE + select NO_BOOTMEM +--- a/arch/arm/boot/compressed/Makefile ++++ b/arch/arm/boot/compressed/Makefile +@@ -106,6 +106,7 @@ ifeq ($(CONFIG_FUNCTION_TRACER),y) + ORIG_CFLAGS := $(KBUILD_CFLAGS) + KBUILD_CFLAGS = $(subst -pg, , $(ORIG_CFLAGS)) + endif ++KBUILD_CFLAGS_KERNEL := $(patsubst -f%-sections,,$(KBUILD_CFLAGS_KERNEL)) + + # -fstack-protector-strong triggers protection checks in this code, + # but it is being used too early to link to meaningful stack_chk logic. +--- a/arch/arm/kernel/vmlinux.lds.S ++++ b/arch/arm/kernel/vmlinux.lds.S +@@ -100,24 +100,24 @@ SECTIONS + } + .init.arch.info : { + __arch_info_begin = .; +- *(.arch.info.init) ++ KEEP(*(.arch.info.init)) + __arch_info_end = .; + } + .init.tagtable : { + __tagtable_begin = .; +- *(.taglist.init) ++ KEEP(*(.taglist.init)) + __tagtable_end = .; + } + #ifdef CONFIG_SMP_ON_UP + .init.smpalt : { + __smpalt_begin = .; +- *(.alt.smp.init) ++ KEEP(*(.alt.smp.init)) + __smpalt_end = .; + } + #endif + .init.pv_table : { + __pv_table_begin = .; +- *(.pv_table) ++ KEEP(*(.pv_table)) + __pv_table_end = .; + } + +--- a/arch/arm/kernel/vmlinux.lds.h ++++ b/arch/arm/kernel/vmlinux.lds.h +@@ -22,13 +22,13 @@ + #define ARM_MMU_DISCARD(x) + #else + #define ARM_MMU_KEEP(x) +-#define ARM_MMU_DISCARD(x) x ++#define ARM_MMU_DISCARD(x) KEEP(x) + #endif + + #define PROC_INFO \ + . = ALIGN(4); \ + __proc_info_begin = .; \ +- *(.proc.info.init) \ ++ KEEP(*(.proc.info.init)) \ + __proc_info_end = .; + + #define HYPERVISOR_TEXT \ +@@ -39,11 +39,11 @@ + #define IDMAP_TEXT \ + ALIGN_FUNCTION(); \ + __idmap_text_start = .; \ +- *(.idmap.text) \ ++ KEEP(*(.idmap.text)) \ + __idmap_text_end = .; \ + . = ALIGN(PAGE_SIZE); \ + __hyp_idmap_text_start = .; \ +- *(.hyp.idmap.text) \ ++ KEEP(*(.hyp.idmap.text)) \ + __hyp_idmap_text_end = .; + + #define ARM_DISCARD \ +@@ -86,12 +86,12 @@ + . = ALIGN(8); \ + .ARM.unwind_idx : { \ + __start_unwind_idx = .; \ +- *(.ARM.exidx*) \ ++ KEEP(*(.ARM.exidx*)) \ + __stop_unwind_idx = .; \ + } \ + .ARM.unwind_tab : { \ + __start_unwind_tab = .; \ +- *(.ARM.extab*) \ ++ KEEP(*(.ARM.extab*)) \ + __stop_unwind_tab = .; \ + } + +@@ -102,14 +102,14 @@ + #define ARM_VECTORS \ + __vectors_start = .; \ + .vectors 0xffff0000 : AT(__vectors_start) { \ +- *(.vectors) \ ++ KEEP(*(.vectors)) \ + } \ + . = __vectors_start + SIZEOF(.vectors); \ + __vectors_end = .; \ + \ + __stubs_start = .; \ + .stubs ADDR(.vectors) + 0x1000 : AT(__stubs_start) { \ +- *(.stubs) \ ++ KEEP(*(.stubs)) \ + } \ + . = __stubs_start + SIZEOF(.stubs); \ + __stubs_end = .; \ +--- a/arch/mips/Kconfig ++++ b/arch/mips/Kconfig +@@ -43,6 +43,7 @@ config MIPS + select HAVE_ARCH_TRANSPARENT_HUGEPAGE if CPU_SUPPORTS_HUGEPAGES && 64BIT + select HAVE_CBPF_JIT if (!64BIT && !CPU_MICROMIPS) + select HAVE_EBPF_JIT if (64BIT && !CPU_MICROMIPS) ++ select HAVE_LD_DEAD_CODE_DATA_ELIMINATION + select HAVE_CONTEXT_TRACKING + select HAVE_COPY_THREAD_TLS + select HAVE_C_RECORDMCOUNT +--- a/arch/mips/kernel/vmlinux.lds.S ++++ b/arch/mips/kernel/vmlinux.lds.S +@@ -72,7 +72,7 @@ SECTIONS + /* Exception table for data bus errors */ + __dbe_table : { + __start___dbe_table = .; +- *(__dbe_table) ++ KEEP(*(__dbe_table)) + __stop___dbe_table = .; + } + +@@ -123,7 +123,7 @@ SECTIONS + . = ALIGN(4); + .mips.machines.init : AT(ADDR(.mips.machines.init) - LOAD_OFFSET) { + __mips_machines_start = .; +- *(.mips.machines.init) ++ KEEP(*(.mips.machines.init)) + __mips_machines_end = .; + } + |