Build Linux Kernel with Intel oneAPI icx (Guide + Automation)

This repository provides a guide-first workflow for building a modern x86-64 Linux kernel with Intel oneAPI LLVM-based tooling.

It includes:

• A practical Intel icx build guide
• Scripts to patch Kbuild for Intel compiler detection
• Scripts to automate configure/build/install commands
• One end-to-end script to run the full flow

Kernel .c files must use icx (C compiler).
icpx is the C++ compiler and is only optional for host-side C++ tools.

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Included scripts

• /home/runner/work/Linux-kernel-intel-c/Linux-kernel-intel-c/scripts/patch_kbuild_for_icx.py
  Patches kernel source tree files:

  • scripts/as-version.sh (treats icx as LLVM IAS)
  • top-level Makefile (selects scripts/Makefile.clang for Intel compiler text)

• /home/runner/work/Linux-kernel-intel-c/Linux-kernel-intel-c/scripts/build_kernel_icx.sh
  Runs make with recommended Intel/LLVM toolchain variables and KCFLAGS="-ffreestanding -fno-builtin".

• /home/runner/work/Linux-kernel-intel-c/Linux-kernel-intel-c/scripts/full_kernel_icx_flow.sh
  One all-in-one script that checks tools, patches Kbuild, prepares config, builds, and optionally installs.

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Why these changes are needed

Intel icx is LLVM-based but its compiler identity is not always detected by kernel logic that expects typical Clang strings.

Two build-system touchpoints matter:

1. scripts/as-version.sh must classify icx as LLVM integrated assembler
2. top-level Makefile must choose scripts/Makefile.clang for Intel compiler version text

Also, to prevent unresolved Intel runtime symbols in kernel/module objects, use:

• -ffreestanding
• -fno-builtin

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Quick start

1. Prepare dependencies (kernel deps + LLVM tools + oneAPI with icx/icpx)
2. Run the all-in-one script:

/home/runner/work/Linux-kernel-intel-c/Linux-kernel-intel-c/scripts/full_kernel_icx_flow.sh \
  --kernel-src /path/to/linux \
  --jobs 10

3. Optional install step:

/home/runner/work/Linux-kernel-intel-c/Linux-kernel-intel-c/scripts/full_kernel_icx_flow.sh \
  --kernel-src /path/to/linux \
  --jobs 10 \
  --install

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Manual script usage

1) Patch kernel build files for Intel LLVM detection

python3 /home/runner/work/Linux-kernel-intel-c/Linux-kernel-intel-c/scripts/patch_kbuild_for_icx.py \
  --kernel-src /path/to/linux

2) Build with Intel/LLVM toolchain

/home/runner/work/Linux-kernel-intel-c/Linux-kernel-intel-c/scripts/build_kernel_icx.sh \
  --kernel-src /path/to/linux \
  --jobs 10

3) Full build command used by the script

make -j10 \
  CC=icx \
  LD=ld.lld \
  AR=llvm-ar \
  NM=llvm-nm \
  STRIP=llvm-strip \
  OBJCOPY=llvm-objcopy \
  OBJDUMP=llvm-objdump \
  READELF=llvm-readelf \
  LLVM_IAS=1 \
  KCFLAGS="-ffreestanding -fno-builtin" \
  bzImage modules

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Notes

• Use CC=icx for kernel C compilation.
• Keep host tools on GCC/binutils unless you explicitly want Intel/LLVM host tools.
• If ORC/objtool issues appear, fallback to frame-pointer unwinder can be used in config.
• Prefer INSTALL_MOD_STRIP=1 during module install to avoid oversized .ko files.