building and using modules on arm64 hikey board

[Ard Biesheuvel]

This is likely caused by the fact that the Android AArch64 toolchain uses -fpic by default. Could you try adding -fno-pic to the CFLAGS?


> On 30 mei 2016, at 12:21, Arend Van Spriel <arend.vanspriel at broadcom.com> wrote:
> 
> I got myself an arm64 HiKey board from LeMaker and build an Android AOSP
> image for it (see [1]). For development I would like to use
> CONFIG_MODULES. However, when I try to insmod the build module I get:
> 
> [  287.903653] module cfg80211: overflow in relocation type 261 val
> ffffffbffc006530
> 
> Looking AArch64 ELF documentation [2], section 4.6.5, it has:
> code|name            |operation |overflow check   |
> 261 |R_AARCH64_PREL32|S + A - P |-2^31 <= X < 2^32|
> 
> So basically the highest 32 bits should all be one and so ffffffbf is
> invalid. From what I could find searching internet it could be an issue
> with linker options so I build kernel and modules with V=1. Here the
> linker invocation for them:
> 
> + aarch64-linux-android-ld -EL -p --no-undefined -X --build-id -o vmlinux \
> -T ./arch/arm64/kernel/vmlinux.lds arch/arm64/kernel/head.o
> init/built-in.o \
> --start-group usr/built-in.o arch/arm64/kernel/built-in.o
> arch/arm64/mm/built-in.o \
> arch/arm64/net/built-in.o arch/arm64/kvm/built-in.o
> arch/arm64/crypto/built-in.o \
> ./drivers/firmware/efi/libstub/lib.a kernel/built-in.o certs/built-in.o
> mm/built-in.o \
> fs/built-in.o ipc/built-in.o security/built-in.o crypto/built-in.o
> block/built-in.o \
> arch/arm64/lib/lib.a lib/lib.a arch/arm64/lib/built-in.o lib/built-in.o
> drivers/built-in.o \
> sound/built-in.o firmware/built-in.o net/built-in.o virt/built-in.o
> --end-group .tmp_kallsyms2.o
> 
>  aarch64-linux-android-ld -EL -r  -T ./scripts/module-common.lds
> --build-id \
>  -o net/wireless/cfg80211.ko net/wireless/cfg80211.o
> net/wireless/cfg80211.mod.o
> 
> Attached are vmlinux.lds and module-common.lds. I also tried taking
> upstream arch/arm64/kernel/module.lds in hikey-linaro tree. If someone
> can give a hint or educated guess at what to try it would be appreciated.
> 
> Regards,
> Arend
> 
> [1] https://source.android.com/source/devices.html#building-kernel
> [2]
> http://infocenter.arm.com/help/topic/com.arm.doc.ihi0056b/IHI0056B_aaelf64.pdf
> <module-common.lds>
> <vmlinux.lds>