This goes on top of Nick's latest version of "[PATCH 0/6 v2] kbuild changes,
thin archives, --gc-sections" and enables both features on ARM.
It's a bit half-baked, these are known problems:
- as big-endian support is still broken, I disable it in Kconfig
so an allyesconfig build ends up as little-endian
- I've thrown in a change to include/asm-generic/vmlinux.lds.h
but don't know whether this is the right way or not. We have
to keep .text.fixup linked together with .text, but I separate
out .text.unlikely and .text.hot again. This has not caused
any link failures for me (yet).
- I mark a ton of sections as KEEP() in vmlinux.lds.S. Some of
them might not actually be needed, and I have not spent much
time checking what they actually are. However, I did build
a few hundred randconfigs without new issues.
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index b62ae32f8a1e..9bf37a6e7384 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -83,6 +83,7 @@ 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
@@ -92,6 +93,7 @@ config ARM
select PERF_USE_VMALLOC
select RTC_LIB
select SYS_SUPPORTS_APM_EMULATION
+ select THIN_ARCHIVES
# Above selects are sorted alphabetically; please add new ones
# according to that. Thanks.
help
diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
index ad325a8c7e1e..b7f2a41fd940 100644
--- a/arch/arm/kernel/Makefile
+++ b/arch/arm/kernel/Makefile
@@ -13,6 +13,9 @@ endif
CFLAGS_REMOVE_return_address.o = -pg
+ccflags-y += -fno-function-sections -fno-data-sections
+subdir-ccflags-y += -fno-function-sections -fno-data-sections
+
# Object file lists.
obj-y := elf.o entry-common.o irq.o opcodes.o \
diff --git a/arch/arm/kernel/vmlinux-xip.lds.S b/arch/arm/kernel/vmlinux-xip.lds.S
index 56c8bdf776bd..77c2c607cdd9 100644
--- a/arch/arm/kernel/vmlinux-xip.lds.S
+++ b/arch/arm/kernel/vmlinux-xip.lds.S
@@ -12,17 +12,17 @@
#define PROC_INFO \
. = ALIGN(4); \
VMLINUX_SYMBOL(__proc_info_begin) = .; \
- *(.proc.info.init) \
+ KEEP(*(.proc.info.init)) \
VMLINUX_SYMBOL(__proc_info_end) = .;
#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
@@ -93,7 +93,7 @@ SECTIONS
_stext = .; /* Text and read-only data */
IDMAP_TEXT
__exception_text_start = .;
- *(.exception.text)
+ KEEP(*(.exception.text))
__exception_text_end = .;
IRQENTRY_TEXT
TEXT_TEXT
@@ -114,7 +114,7 @@ SECTIONS
__ex_table : AT(ADDR(__ex_table) - LOAD_OFFSET) {
__start___ex_table = .;
#ifdef CONFIG_MMU
- *(__ex_table)
+ KEEP(*(__ex_table))
#endif
__stop___ex_table = .;
}
@@ -126,12 +126,12 @@ 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
@@ -146,14 +146,14 @@ 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 = .;
@@ -169,24 +169,24 @@ 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 : {
diff --git a/arch/arm/kernel/vmlinux.lds.S b/arch/arm/kernel/vmlinux.lds.S
index 7396a5f00c5f..61b9b8784036 100644
--- a/arch/arm/kernel/vmlinux.lds.S
+++ b/arch/arm/kernel/vmlinux.lds.S
@@ -17,7 +17,7 @@
#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 \
@@ -104,7 +104,7 @@ SECTIONS
_stext = .; /* Text and read-only data */
IDMAP_TEXT
__exception_text_start = .;
- *(.exception.text)
+ KEEP(*(.exception.text))
__exception_text_end = .;
IRQENTRY_TEXT
SOFTIRQENTRY_TEXT
@@ -169,14 +169,14 @@ 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 = .;
@@ -192,24 +192,24 @@ 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 : {
diff --git a/arch/arm/mm/Kconfig b/arch/arm/mm/Kconfig
index 6a09cc204b07..7117b8e99de8 100644
--- a/arch/arm/mm/Kconfig
+++ b/arch/arm/mm/Kconfig
@@ -717,6 +717,7 @@ config SWP_EMULATE
config CPU_BIG_ENDIAN
bool "Build big-endian kernel"
depends on ARCH_SUPPORTS_BIG_ENDIAN
+ depends on !THIN_ARCHIVES
help
Say Y if you plan on running a kernel in big-endian mode.
Note that your board must be properly built and your board
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index 9136c3afd3c6..e01f0b00a678 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -433,7 +433,9 @@
* during second ld run in second ld pass when generating System.map */
#define TEXT_TEXT \
ALIGN_FUNCTION(); \
- *(.text.hot .text .text.fixup .text.unlikely .text.*) \
+ *(.text.hot .text.hot.*) \
+ *(.text.unlikely .text.unlikely.*) \
+ *(.text .text.*) \
*(.ref.text) \
MEM_KEEP(init.text) \
MEM_KEEP(exit.text) \
--
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