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Subject[PATCH v2 2/2] powerpc: Allow selection of CONFIG_LD_DEAD_CODE_DATA_ELIMINATION
Date
This option does dead code and data elimination with the linker by
compiling with -ffunction-sections -fdata-sections and linking with
--gc-sections.

By selecting this option on mpc885_ads_defconfig,
vmlinux LOAD segment size gets reduced by 10%

Program Header before the patch:
LOAD off 0x00010000 vaddr 0xc0000000 paddr 0x00000000 align 2**16
filesz 0x0036eda4 memsz 0x0038de04 flags rwx

Program Header after the patch:
LOAD off 0x00010000 vaddr 0xc0000000 paddr 0x00000000 align 2**16
filesz 0x00316da4 memsz 0x00334268 flags rwx

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
arch/powerpc/Kconfig | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 8fe4353be5e3..e1fac49cf465 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -888,6 +888,14 @@ config PPC_MEM_KEYS

If unsure, say y.

+config PPC_UNUSED_ELIMINATION
+ bool "Eliminate unused functions and data from vmlinux"
+ default n
+ select LD_DEAD_CODE_DATA_ELIMINATION
+ help
+ Select this to do dead code and data elimination with the linker
+ by compiling with -ffunction-sections -fdata-sections and linking
+ with --gc-sections.
endmenu

config ISA_DMA_API
--
2.13.3
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