Messages in this thread | | | Subject | Re: [PATCH] powerpc: Allow selection of CONFIG_LD_DEAD_CODE_DATA_ELIMINATION | From | Christophe LEROY <> | Date | Tue, 17 Apr 2018 18:49:44 +0200 |
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Le 17/04/2018 à 18:45, Mathieu Malaterre a écrit : > On Tue, Apr 17, 2018 at 12:49 PM, Christophe Leroy > <christophe.leroy@c-s.fr> 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 <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 >> > > 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 >>
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