From mboxrd@z Thu Jan 1 00:00:00 1970 From: arend.vanspriel@broadcom.com (Arend Van Spriel) Date: Wed, 1 Jun 2016 11:01:42 +0200 Subject: building and using modules on arm64 hikey board In-Reply-To: References: <87a3195c-febb-a6c8-a679-272b9f7b59cc@broadcom.com> <0240F9F0-0146-4DCC-B512-195415B29B34@linaro.org> Message-ID: <370e5b2b-7f7d-6912-0f8e-71324974a9cb@broadcom.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 31-5-2016 22:58, Ard Biesheuvel wrote: > On 31 May 2016 at 22:24, Dmitry Shmidt wrote: >> On Mon, May 30, 2016 at 4:30 AM, 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? >> >> Actually Arend is using 4.4, and we need to pull your fix, Ard: >> >> commit 80a2d83376001f6a1993f2e925670ab0e4cdb76d >> Author: Ard Biesheuvel >> Date: Tue Jan 5 10:18:52 2016 +0100 >> >> arm64: module: avoid undefined shift behavior in reloc_data() >> > > OK, that was going to be my next question to Arend, i.e., to check > whether he has all the recent fixes we did for the module loader. > > But I'd also like to understand how we ended up with PREL32 > relocations in the first place, since those are quite unusual in > object code generated from generic C source code when using the > non-pic small model, which is normally GCC's default. Are there any > other code generation defaults for the Android AArch64 GCC toolchain > that you are aware of? For the module I noticed it uses command line parameter -mcmodel=large so I suppose that could be how I ended up with PREL32. In arch/arm64/Makefile there is this: ifeq ($(CONFIG_ARM64_ERRATUM_843419), y) KBUILD_CFLAGS_MODULE += -mcmodel=large endif And that Kconfig item is indeed set. Regards, Arend >>>> On 30 mei 2016, at 12:21, Arend Van Spriel 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 >>>> >>>> >>> >>> _______________________________________________ >>> linux-arm-kernel mailing list >>> linux-arm-kernel at lists.infradead.org >>> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel