Commit 5d20ee31 authored by Nicholas Piggin's avatar Nicholas Piggin Committed by Masahiro Yamada
Browse files

kbuild: Allow LD_DEAD_CODE_DATA_ELIMINATION to be selectable if enabled 



Architectures that are capable can select
HAVE_LD_DEAD_CODE_DATA_ELIMINATION to enable selection of that
option (as an EXPERT kernel option).

Signed-off-by: default avatarNicholas Piggin <npiggin@gmail.com>
Signed-off-by: default avatarMasahiro Yamada <yamada.masahiro@socionext.com>
parent 6ca8d943

arch/Kconfig

+0 −15
Original line number Diff line number Diff line
@@ -596,21 +596,6 @@ config CC_STACKPROTECTOR_AUTO 


endchoice



config LD_DEAD_CODE_DATA_ELIMINATION

	bool

	help

	  Select this if the architecture wants to do dead code and

	  data elimination with the linker by compiling with

	  -ffunction-sections -fdata-sections and linking with

	  --gc-sections.



	  This requires that the arch annotates or otherwise protects

	  its external entry points from being discarded. Linker scripts

	  must also merge .text.*, .data.*, and .bss.* correctly into

	  output sections. Care must be taken not to pull in unrelated

	  sections (e.g., '.text.init'). Typically '.' in section names

	  is used to distinguish them from label names / C identifiers.



config HAVE_ARCH_WITHIN_STACK_FRAMES

	bool

	help

init/Kconfig

+27 −0
Original line number Diff line number Diff line
@@ -1038,6 +1038,33 @@ config CC_OPTIMIZE_FOR_SIZE 


endchoice



config HAVE_LD_DEAD_CODE_DATA_ELIMINATION

	bool

	help

	  This requires that the arch annotates or otherwise protects

	  its external entry points from being discarded. Linker scripts

	  must also merge .text.*, .data.*, and .bss.* correctly into

	  output sections. Care must be taken not to pull in unrelated

	  sections (e.g., '.text.init'). Typically '.' in section names

	  is used to distinguish them from label names / C identifiers.



config LD_DEAD_CODE_DATA_ELIMINATION

	bool "Dead code and data elimination (EXPERIMENTAL)"

	depends on HAVE_LD_DEAD_CODE_DATA_ELIMINATION

	depends on EXPERT

	help

	  Select this if the architecture wants to do dead code and

	  data elimination with the linker by compiling with

	  -ffunction-sections -fdata-sections, and linking with

	  --gc-sections.



	  This can reduce on disk and in-memory size of the kernel

	  code and static data, particularly for small configs and

	  on small systems. This has the possibility of introducing

	  silently broken kernel if the required annotations are not

	  present. This option is not well tested yet, so use at your

	  own risk.



config SYSCTL

	bool