On 30-05-16 13:30, Ard Biesheuvel wrote:

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?

I did only to notice with 'make V=1 ...' that it was already used hence
showing up in the compile command line twice. To no avail so that ain't
working.

Regards,
Arend

quoted

On 30 mei 2016, at 12:21, Arend Van Spriel [off-list ref] 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>