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arm: config: enforce -fno-pic for gcc

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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@nxp.com>
Cc: Albert Aribaud <albert.u.boot@aribaud.net>
Reviewed-by: Tom Rini <trini@konsulko.com>
This commit is contained in:
Peng Fan 2016-01-30 12:10:49 +08:00 committed by Albert ARIBAUD
parent c5e954eccd
commit 397d7d5a1b
1 changed files with 1 additions and 0 deletions
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arch/arm/config.mk
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@ -107,6 +107,7 @@ 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.