Talk:Step-by-step Native Compiling a Kernel

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  1. note a 'large' initrd is created. Probably a feature-bloated busybox

Here is a forum link to kernel building:

This is mdrjr post for quick reference:

git clone --depth 1 git:// -b odroid-3.0.y kernel-source
cd kernel-source

make odroidu2_ubuntu_mali_defconfig <- if you want to have 3D enabled
make odroidu2_ubuntu_defconfig <- if you don't care about 3D

make menuconfig

go around on the menus, searching for l2tp or things that are used on the IPSeC to add it. When you done..

make -j5 zImage modules
make modules_install
cp arch/arch/boot/zImage /media/boot

sync && reboot


Here is the magic for hardfloat kernel build:

Update: When doing a local build you should specify that you want a hardfloat kernel. This will allow Linux access to the floating point hardware
which it will use for additional registers when calling library routines. That will give a nice boost to performance
To make it easy to recall the options I stick the environment variables in a shell script in /usr/local/bin. You could also place it in /etc/bash.bashrc if you do not mind it
always being set.

# cat /usr/local/bin/
export CFLAGS="-O2 -pipe -mfpu=neon -mcpu=armv7l -mfloat-abi=hard"

To execute it: . /usr/local/bin/
(note: there is a DOT in front of the shell script invocation followed by a space, that will export the flags to the parent shell)

Here is a link to mlinuxguy post on forum:

Here is what I see: (readelf -A) File: ./arch/arm/vfp/vfp.o Attribute Section: aeabi File Attributes

 Tag_CPU_name: "7-A"
 Tag_CPU_arch: v7
 Tag_CPU_arch_profile: Application
 Tag_ARM_ISA_use: Yes
 Tag_THUMB_ISA_use: Thumb-2
 Tag_FP_arch: VFPv3
 Tag_Advanced_SIMD_arch: NEONv1
 Tag_ABI_PCS_wchar_t: 4
 Tag_ABI_FP_number_model: Finite
 Tag_ABI_align_needed: 8-byte
 Tag_ABI_enum_size: int
 Tag_ABI_optimization_goals: Aggressive Speed
 Tag_CPU_unaligned_access: v6
 Tag_DIV_use: Not allowed

Link to raspi kernel build info: