Thread (9 messages) 9 messages, 4 authors, 2016-06-01

building and using modules on arm64 hikey board

From: Jisheng Zhang <hidden>
Date: 2016-05-31 01:58:25
Also in: lkml

On Mon, 30 May 2016 20:54:33 +0200
Arend van Spriel [off-list ref] wrote:
On 30-05-16 13:30, Ard Biesheuvel wrote:
quoted
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.
Per my experience, the default ld in android toolchain is gold, can you plz try
to use ld.bfd instead?
Regards,
Arend
quoted
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>  
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