[U-Boot] [RFC V1] arm: config: enforce -fno-pic for gcc

[Peng Fan <b51431@freescale.com>]

Hi Albert,

Do you have any comments on this patch?

Regards,
Peng.

On Sat, Dec 05, 2015 at 03:53:46PM +0800, Peng Fan wrote:
>Android's tool chain enable the -mandroid at default.
>This option will enable the -fpic, which cause uboot compilation
>failure:
>"
> LD      u-boot
> u-boot contains unexpected relocations: R_ARM_ABS32
> R_ARM_RELATIVE
>"
>
>In my testcase, arm-linux-androideabi-gcc-4.9 internally
>enables '-fpic', so when compiling code, there will be
>relocation entries using type R_ARM_GOT_BREL and .got
>section. When linking all the built-in.o using ld, there
>will be R_ARM_ABS32 relocation entry and .got section
>in the final u-boot elf image. This can not be handled
>by u-boot, since u-boot only expects R_ARM_RELATIVE
>relocation entry.
>arm-poky-linux-gnueabi-gcc-4.9 default does not enable '-fpic',
>so there is not .got section and R_ARM_GOT_BREL in built-in.o.
>And in the final u-boot elf image, all relocation entries are
>R_ARM_RELATIVE.
>
>we can pass '-fno-pic' to xxx-gcc to disable pic. whether
>the toolchain internally enables or disables pic, '-fno-pic'
>can work well.
>
>Signed-off-by: Peng Fan <Peng.Fan@freescale.com>
>Cc: Albert Aribaud <albert.u.boot@aribaud.net>
>---
> arch/arm/config.mk | 1 +
> 1 file changed, 1 insertion(+)
>
>diff --git a/arch/arm/config.mk b/arch/arm/config.mk
>index 0550225..2b6322a 100644
>--- a/arch/arm/config.mk
>+++ b/arch/arm/config.mk
>@@ -106,6 +106,7 @@ ALL-y += checkarmreloc
> # instruction. Relocation is not supported for that case, so disable
> # such usage by requiring word relocations.
> PLATFORM_CPPFLAGS += $(call cc-option, -mword-relocations)
>+PLATFORM_CPPFLAGS += $(call cc-option, -fno-pic)
> endif
> 
> # limit ourselves to the sections we want in the .bin.
>-- 
>2.6.2
>
>

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