Kernel Building

Build Linux kernels for ARM64, ARM, and RISC-V on macOS.

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Prerequisites

• Workspace initialized: elmos init
• Dependencies checked: elmos doctor

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Build Workflow

1. Set Architecture

elmos arch arm64    # or: arm, riscv
elmos arch          # Show current

2. Configure Kernel

# Default config for architecture
elmos kernel config defconfig

# Interactive menu
elmos kernel config menuconfig

# Minimal config
elmos kernel config tinyconfig

Valid config types:

Type	Description
defconfig	Architecture default
tinyconfig	Minimal kernel
menuconfig	Interactive menu
kvm_guest.config	KVM optimized
oldconfig	Update existing
olddefconfig	Update with defaults

3. Build

# Default targets (Image, dtbs, modules)
elmos kernel build

# Specific targets
elmos kernel build Image
elmos kernel build vmlinux

# Custom parallelism
elmos kernel build -j 8

Valid build targets:

Target	Description
Image	Kernel image (arm64, riscv)
zImage	Compressed image (arm)
dtbs	Device tree blobs
modules	Kernel modules
vmlinux	Uncompressed kernel (for GDB)

4. Verify Build

elmos status

Output:

Workspace Status:
  Volume: /Volumes/elmos (mounted)
  Kernel: ✓ Configured, ✓ Built
  Architecture: arm64
  Image: /Volumes/elmos/linux/arch/arm64/boot/Image

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BuildOptions Reference

// core/domain/builder/kernel.go
type BuildOptions struct {
    Jobs    int      // Parallel jobs (-j)
    Targets []string // Build targets
}

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Environment Variables

ELMOS automatically sets:

Variable	Value
ARCH	Target architecture
LLVM	1 (use LLVM toolchain)
CROSS_COMPILE	Toolchain prefix
HOSTCFLAGS	macOS compatibility flags
PATH	Prepends LLVM, GNU tools

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Clean Build

elmos kernel clean    # make distclean

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Patches

Apply macOS compatibility patches:

# List available
elmos patch list

# Apply
elmos patch apply v6.18/generic/fix-copy-range

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Troubleshooting

Issue	Solution
"No toolchain"	Run elmos doctor
Config errors	Run elmos kernel clean then reconfigure
Build hangs	Check disk space, reduce -j
Missing headers	Run elmos doctor --fix