[SOLVED] Compiling Linux for ARM Embedded

Hi all,

First things first, sorry if this is in the wrong place. I couldn't find a forum on here that this question fits neatly into, so if the mods think it's in the wrong place, I apologize, and invite you to move it if you see fit.

With that out of the way, here's the problem: I'm trying to cross compile Linux 3.15.1 for ARM, as I am developing a new board. So far so good. I've built a cross-compiler, and associated toolchain, and I've installed U-boot mkimage. Great. I've configured the kernel, but when I try to build it, the compiler complains:

bash-4.2$ make bzImage
  CHK     include/config/kernel.release
  CHK     include/generated/uapi/linux/version.h
  CHK     include/generated/utsrelease.h
  CC      kernel/bounds.s
arm-none-eabi-gcc: error: unrecognized command line option '-m64'
arm-none-eabi-gcc: error: unrecognized command line option '-mno-mmx'
arm-none-eabi-gcc: error: unrecognized command line option '-mno-sse'
arm-none-eabi-gcc: error: unrecognized command line option '-mno-red-zone'
arm-none-eabi-gcc: error: unrecognized command line option '-mcmodel=kernel'
make[1]: *** [kernel/bounds.s] Error 1
make: *** [prepare0] Error 2

Clearly, this is due to the fact that the kernel makefile is trying to build for the x86 architecture, however, I am unaware of how to change the target to 32 bit ARM. Several hours of Googling seems to indicate that I need a patch for the kernel when cross-compiling. As to the accuracy and releventness of this I'm not too sure, as the only instructions I could find were pertaining to the 2.6 line of kernels.

As such, my question is this: Do I need to find an ARM patch, and if so, where can I find one for 3.15.1? If not, how do I retarget the compilation scripts to ARM 32-bit, to kill these errors so I can get an image booting?

Thanks in advance, and let me know if there's any more information I've left out
Connor

Here is the Repo for openSUSE's kernel-source-3.15 for ARM architecture. Remember that ARM has different structures. I believe this repo is for ARM7. I mostly mess with Raspberry Pi. I've got openSUSE 13.1 working with desktop, but it's sure not fast. Anyway, here's the URL: openSUSE ARM kernel-source

Maybe some further parameters have to be added to the 'make' command. Check 'Makefile' in the kernel source root directory, it should give some instructions for the required extra parameters. For example (at least for 2.6.xxx kernels), "ARCH=xxx" parameter has to be supplied, unless ARCH is not set in the environment.

This is a snippet of my Makefile

make -j5 \
CONFIG_DEBUG_SECTION_MISMATCH=y \
CROSS_COMPILE=$(TARGET)- ARCH=$(ARCH) \
KALLSYMS_EXTRA_PASS=1 \
LOADADDR=0x80008000 \
$(KERNEL_IMAGE) modules && \
make $(VERBOSITY) INSTALL_MOD_PATH=$(TARGETFS) \
CONFIG_DEBUG_SECTION_MISMATCH=y \
CROSS_COMPILE=$(TARGET)- ARCH=$(ARCH) \
DEPMOD=$(TARGET)/sbin/$(TARGET)-depmod \
modules_install

where
TARGET=arm-cortex_a8-linux-gnueabi
ARCH=arm
KERNEL_IMAGE=zImage
TARGETGS is where you are building your root file system

Do you have change the Makefile ?


this is my Makefile：

export KBUILD_BUILDHOST := $(SUBARCH)
ARCH ?= arm
CROSS_COMPILE ?= arm-linux-

Originally Posted by lazac Maybe some further parameters have to be added to the 'make' command. Check 'Makefile' in the kernel source root directory, it should give some instructions for the required extra parameters. For example (at least for 2.6.xxx kernels), "ARCH=xxx" parameter has to be supplied, unless ARCH is not set in the environment.

do you have success in compiling Linux for ARM Embedded （2.6.xxx kernels）？？？

At the top of my Makefile is
include config.mk
That file specifies the details:
export SHELL=/bin/bash
export ARCH=arm
export BUILDARCH:=$(shell uname -m)
export TARGET=arm-cortex_a8-linux-gnueabi
export CROSS_COMPILE=$(TARGET)-

export KERNEL_VERSION=3.13.2

The only other piece is TARGETFS which contains the root of your target file system. Mine is similar to
~/$(TARGET)/$(TARGET)/sysroot
as I am using crosstool-ng

Also make sure that the .config has the arch set to arm. Should be within the first ten-ish lines of the .config file. With make menuconfig to change it. Or xconfig, and many other variants.