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-rw-r--r--target/linux/generic/hack-4.19/220-gc_sections.patch258
1 files changed, 258 insertions, 0 deletions
diff --git a/target/linux/generic/hack-4.19/220-gc_sections.patch b/target/linux/generic/hack-4.19/220-gc_sections.patch
new file mode 100644
index 0000000000..d257232403
--- /dev/null
+++ b/target/linux/generic/hack-4.19/220-gc_sections.patch
@@ -0,0 +1,258 @@
+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
+@@ -272,6 +272,11 @@ else
+ scripts/Kbuild.include: ;
+ include scripts/Kbuild.include
+
++ifdef CONFIG_LD_DEAD_CODE_DATA_ELIMINATION
++KBUILD_CFLAGS_KERNEL += $(call cc-option,-ffunction-sections,)
++KBUILD_CFLAGS_KERNEL += $(call cc-option,-fdata-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)
+@@ -788,11 +793,6 @@ 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 += $(call cc-option,-ffunction-sections,)
+-KBUILD_CFLAGS += $(call cc-option,-fdata-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)
+ CHECKFLAGS += $(NOSTDINC_FLAGS)
+--- a/arch/arm/Kconfig
++++ b/arch/arm/Kconfig
+@@ -91,6 +91,7 @@ config ARM
+ select HAVE_UID16
+ select HAVE_VIRT_CPU_ACCOUNTING_GEN
+ select IRQ_FORCED_THREADING
++ select LD_DEAD_CODE_DATA_ELIMINATION
+ select MODULES_USE_ELF_REL
+ select NO_BOOTMEM
+ select OF_EARLY_FLATTREE if OF
+--- a/arch/arm/boot/compressed/Makefile
++++ b/arch/arm/boot/compressed/Makefile
+@@ -103,6 +103,7 @@ ifeq ($(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
+@@ -18,7 +18,7 @@
+ #define PROC_INFO \
+ . = ALIGN(4); \
+ VMLINUX_SYMBOL(__proc_info_begin) = .; \
+- *(.proc.info.init) \
++ KEEP(*(.proc.info.init)) \
+ VMLINUX_SYMBOL(__proc_info_end) = .;
+
+ #define HYPERVISOR_TEXT \
+@@ -29,11 +29,11 @@
+ #define IDMAP_TEXT \
+ ALIGN_FUNCTION(); \
+ VMLINUX_SYMBOL(__idmap_text_start) = .; \
+- *(.idmap.text) \
++ KEEP(*(.idmap.text)) \
+ VMLINUX_SYMBOL(__idmap_text_end) = .; \
+ . = ALIGN(PAGE_SIZE); \
+ VMLINUX_SYMBOL(__hyp_idmap_text_start) = .; \
+- *(.hyp.idmap.text) \
++ KEEP(*(.hyp.idmap.text)) \
+ VMLINUX_SYMBOL(__hyp_idmap_text_end) = .;
+
+ #ifdef CONFIG_HOTPLUG_CPU
+@@ -106,7 +106,7 @@ SECTIONS
+ _stext = .; /* Text and read-only data */
+ IDMAP_TEXT
+ __exception_text_start = .;
+- *(.exception.text)
++ KEEP(*(.exception.text))
+ __exception_text_end = .;
+ IRQENTRY_TEXT
+ SOFTIRQENTRY_TEXT
+@@ -135,7 +135,7 @@ SECTIONS
+ __ex_table : AT(ADDR(__ex_table) - LOAD_OFFSET) {
+ __start___ex_table = .;
+ #ifdef CONFIG_MMU
+- *(__ex_table)
++ KEEP(*(__ex_table))
+ #endif
+ __stop___ex_table = .;
+ }
+@@ -147,12 +147,12 @@ SECTIONS
+ . = 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 = .;
+ }
+ #endif
+@@ -172,14 +172,14 @@ SECTIONS
+ */
+ __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 = .;
+@@ -195,24 +195,24 @@ 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 = .;
+ }
+ .init.data : {
+--- a/arch/mips/Kconfig
++++ b/arch/mips/Kconfig
+@@ -40,6 +40,7 @@ config MIPS
+ select HAVE_CBPF_JIT if (!64BIT && !CPU_MICROMIPS)
+ select HAVE_EBPF_JIT if (64BIT && !CPU_MICROMIPS)
+ select HAVE_CC_STACKPROTECTOR
++ select 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 = .;
+ }
+
+--- a/include/asm-generic/vmlinux.lds.h
++++ b/include/asm-generic/vmlinux.lds.h
+@@ -105,7 +105,7 @@
+ #ifdef CONFIG_FTRACE_MCOUNT_RECORD
+ #define MCOUNT_REC() . = ALIGN(8); \
+ VMLINUX_SYMBOL(__start_mcount_loc) = .; \
+- *(__mcount_loc) \
++ KEEP(*(__mcount_loc)) \
+ VMLINUX_SYMBOL(__stop_mcount_loc) = .;
+ #else
+ #define MCOUNT_REC()
+@@ -113,7 +113,7 @@
+
+ #ifdef CONFIG_TRACE_BRANCH_PROFILING
+ #define LIKELY_PROFILE() VMLINUX_SYMBOL(__start_annotated_branch_profile) = .; \
+- *(_ftrace_annotated_branch) \
++ KEEP(*(_ftrace_annotated_branch)) \
+ VMLINUX_SYMBOL(__stop_annotated_branch_profile) = .;
+ #else
+ #define LIKELY_PROFILE()
+@@ -121,7 +121,7 @@
+
+ #ifdef CONFIG_PROFILE_ALL_BRANCHES
+ #define BRANCH_PROFILE() VMLINUX_SYMBOL(__start_branch_profile) = .; \
+- *(_ftrace_branch) \
++ KEEP(*(_ftrace_branch)) \
+ VMLINUX_SYMBOL(__stop_branch_profile) = .;
+ #else
+ #define BRANCH_PROFILE()
+@@ -237,7 +237,8 @@
+ LIKELY_PROFILE() \
+ BRANCH_PROFILE() \
+ TRACE_PRINTKS() \
+- TRACEPOINT_STR()
++ TRACEPOINT_STR() \
++ *(.data.[a-zA-Z_]*)
+
+ /*
+ * Data section helpers
+@@ -496,7 +497,7 @@
+ #define ENTRY_TEXT \
+ ALIGN_FUNCTION(); \
+ VMLINUX_SYMBOL(__entry_text_start) = .; \
+- *(.entry.text) \
++ KEEP(*(.entry.text)) \
+ VMLINUX_SYMBOL(__entry_text_end) = .;
+
+ #define IRQENTRY_TEXT \
+@@ -603,7 +604,7 @@
+ . = ALIGN(sbss_align); \
+ .sbss : AT(ADDR(.sbss) - LOAD_OFFSET) { \
+ *(.dynsbss) \
+- *(.sbss) \
++ *(.sbss .sbss.*) \
+ *(.scommon) \
+ }
+