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authorNicholas Piggin <npiggin@gmail.com>2018-05-09 23:00:00 +1000
committerMasahiro Yamada <yamada.masahiro@socionext.com>2018-05-17 22:45:01 +0900
commit5d20ee3192a58750ef8cc24b21aad23a82689be0 (patch)
tree7a91f8a8ee8ab7126f6d36bad1b0b121746a60c3 /init
parent6ca8d9433d7712d4c3c6102816b685470504dc3d (diff)
downloadlinux-5d20ee3192a58750ef8cc24b21aad23a82689be0.tar.gz
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: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Diffstat (limited to 'init')
-rw-r--r--init/Kconfig27
1 files changed, 27 insertions, 0 deletions
diff --git a/init/Kconfig b/init/Kconfig
index f013afc74b11..1706d963766b 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -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