Le 17/04/2018 à 18:45, Mathieu Malaterre a écrit :
On Tue, Apr 17, 2018 at 12:49 PM, Christophe Leroy
<[email protected]> wrote:
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 <[email protected]>
---
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
Just for reference, I cannot boot my Mac Mini G4 anymore (yaboot). The
messages I can see (prom_init) are:
Which version of GCC do you use ?
Can you provide the generated System.map with and without that option
active ?
Thanks
Christophe
---
done
copying OF device tree...
Building dt strings...
Building dt structure...
Device tree strings 0x01100000 -> 0x01100e02
Device tree struct 0x01101000 -> 0x01109000
Quiescing Open Firmware ...
Booting Linux via __start() @ 0x00140000 ...
_
---
config ISA_DMA_API
--
2.13.3
