Table of contents:

A. How to build XNU

B. How to install a new header file from XNU

C. Building XNU on a Linux x32/x64 host.

D. Installing XNU headers on a Linux x32/x64 host.

E. Installing libkmod/libkmodc++ on a Linux x32/x64 host.

(I am putting this up online as I no longer will have time to personally

maintain this project.)

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A. How to build XNU:

1) Type: "make"

This builds all the components for kernel, architecture, and machine

configurations defined in TARGET_CONFIGS. Additionally, we also support

architectures defined in ARCH_CONFIGS and kernel configurations defined in

KERNEL_CONFIGS. Note that TARGET_CONFIGS overrides any configurations defined

in ARCH_CONFIGS and KERNEL_CONFIGS.

By default, architecture defaults to the build machine

architecture, and the kernel configuration is set to build for DEVELOPMENT.

The machine configuration defaults to ARMPBA8 for arm and nothing for i386 and x86_64.

This will also create a bootable image, mach_kernel, and a kernel binary

with symbols, mach_kernel.sys.

Alternatively, you can edit "machine_configuration" to set the default targets to build

if you are using the xnu-build script.

Here are the valid arm machine configs:

OMAP3530 OMAP3430_RX51 OMAP335X ARMPBA8 S5L8930X S5L8920X S5L8922X

Here are the valid armv6 machine configs: (YOU WILL *NEED* TO USE Xcode 4.4.1 or similar.)

S5L8720X S5L8900XRB ARM_RVEB_V6

Examples:

/* make a debug kernel for OMAP3530 arm board */

make TARGET_CONFIGS="debug arm OMAP3530"

$(OBJROOT)/DEBUG_ARM_OMAP3530/osfmk/DEBUG/osfmk.o: pre-linked object for osfmk component

$(OBJROOT)/DEBUG_ARM_OMAP3530/mach_kernel: bootable image

2) Building a Component

Go to the top directory in your XNU project.

If you are using a sh-style shell, run the following command:

$ . SETUP/setup.sh

If you are using a csh-style shell, run the following command:

% source SETUP/setup.csh

This will define the following environmental variables:

SRCROOT, OBJROOT, DSTROOT, SYMROOT

From a component top directory:

$ make all

This builds a component for all architectures, kernel configurations, and

machine configurations defined in TARGET_CONFIGS (or alternately ARCH_CONFIGS

and KERNEL_CONFIGS).

Example:

$(OBJROOT)/RELEASE_X86_64/osfmk/RELEASE/osfmk.filelist: list of objects in osfmk component

From the component top directory:

$ make mach_kernel

This includes your component in the bootable image, mach_kernel, and

in the kernel binary with symbols, mach_kernel.sys.

WARNING: If a component header file has been modified, you will have to do

the above procedure 1.

3) Building DEBUG

Define kernel configuration to DEBUG in your environment or when running a

make command. Then, apply procedures 4, 5

$ make TARGET_CONFIGS="DEBUG X86_64 DEFAULT" all

or

$ make KERNEL_CONFIGS=DEBUG ARCH_CONFIGS=X86_64 all

or

$ export TARGET_CONFIGS="DEBUG X86_64 DEFAULT"

$ export SDKROOT=/path/to/SDK

$ make all

Example:

$(OBJROOT)/DEBUG_X86_64/osfmk/DEBUG/osfmk.filelist: list of objects in osfmk component

$(OBJROOT)/DEBUG_X86_64/mach_kernel: bootable image

4) Building fat

Define architectures in your environment or when running a make command.

Apply procedures 3, 4, 5

$ make TARGET_CONFIGS="RELEASE I386 DEFAULT RELEASE X86_64 DEFAULT" exporthdrs all

or

$ make ARCH_CONFIGS="I386 X86_64" exporthdrs all

or

$ export ARCH_CONFIGS="I386 X86_64"

$ make exporthdrs all

5) Verbose make

To display complete tool invocations rather than an abbreviated version,

$ make VERBOSE=YES

6) Debug information formats

By default, a DWARF debug information repository is created during the install phase; this is a "bundle" named mach_kernel.dSYM

To select the older STABS debug information format (where debug information is embedded in the mach_kernel.sys image), set the BUILD_STABS environment variable.

$ export BUILD_STABS=1

$ make

7) Build check before integration

From the top directory, run:

$ ~rc/bin/buildit . -arch i386 -arch x86_64 -arch armv7 -arch ppc -noinstallsrc -nosum

xnu supports a number of XBS build aliases, which allow B&I to build

the same source submission multiple times in different ways, to

produce different results. Each build alias supports the standard

"clean", "install", "installsrc", "installhdrs" targets, but

conditionalize their behavior on the RC_ProjectName make variable

which is passed as the -project argument to ~rc/bin/buildit, which

can be one of:

-project xnu # the default, builds /mach_kernel, kernel-space

# headers, user-space headers, man pages,

# symbol-set kexts

-project xnu_debug # a DEBUG kernel in /AppleInternal with dSYM

-project libkxld # user-space version of kernel linker

-project libkmod # static library automatically linked into kexts

-project Libsyscall # automatically generate BSD syscall stubs

8) Creating tags and cscope

Set up your build environment as per instructions in 2a

From the top directory, run:

$ make tags # this will build ctags and etags on a case-sensitive

# volume, only ctags on case-insensitive

$ make TAGS # this will build etags

$ make cscope # this will build cscope database

9) Other makefile options

$ make MAKEJOBS=-j8 # this will use 8 processes during the build. The default is 2x the number of active cores

$ make -w # trace recursive make invocations. Useful in combination with VERBOSE=YES

$ make BUILD_LTO=1 # build with LLVM Link Time Optimization (experimental)

$ make BUILD_INTEGRATED_ASSEMBLER=1 # build with LLVM integrated assembler (experimental)

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B. How to install a new header file from XNU

[Note: This does not cover installing header files in IOKit framework]

1) XNU installs header files at the following locations -

a. $(DSTROOT)/System/Library/Frameworks/Kernel.framework/Headers

b. $(DSTROOT)/System/Library/Frameworks/Kernel.framework/PrivateHeaders

c. $(DSTROOT)/System/Library/Frameworks/System.framework/Headers

d. $(DSTROOT)/System/Library/Frameworks/System.framework/PrivateHeaders

e. $(DSTROOT)/usr/include/

Kernel.framework is used by kernel extensions. System.framework

and /usr/include are used by user level applications. The header

files in framework's "PrivateHeaders" are only available for Apple

Internal development.

2) The directory containing the header file should have a Makefile that

creates the list of files that should be installed at different locations.

If you are adding first header file in a directory, you will need to

create Makefile similar to xnu/bsd/sys/Makefile.

Add your header file to the correct file list depending on where you want

to install it. The default locations where the header files are installed

from each file list are -

a. DATAFILES : To make header file available in user level -

$(DSTROOT)/System/Library/Frameworks/System.framework/Headers

$(DSTROOT)/System/Library/Frameworks/System.framework/PrivateHeaders

$(DSTROOT)/usr/include/

b. PRIVATE_DATAFILES : To make header file available to Apple internal in

user level -

$(DSTROOT)/System/Library/Frameworks/System.framework/PrivateHeaders

c. KERNELFILES : To make header file available in kernel level -

$(DSTROOT)/System/Library/Frameworks/Kernel.framework/Headers

$(DSTROOT)/System/Library/Frameworks/Kernel.framework/PrivateHeaders

d. PRIVATE_KERNELFILES : To make header file available to Apple internal

for kernel extensions -

$(DSTROOT)/System/Library/Frameworks/Kernel.framework/PrivateHeaders

3) The Makefile combines the file lists mentioned above into different

install lists which are used by build system to install the header files.

If the install list that you are interested does not exist, create it

by adding the appropriate file lists. The default install lists, its

member file lists and their default location are described below -

a. INSTALL_MI_LIST : Installs header file to location that is available to

everyone in user level.

Locations -

$(DSTROOT)/System/Library/Frameworks/System.framework/Headers

$(DSTROOT)/usr/include/

Definition -

INSTALL_MI_LIST = ${DATAFILES}

b. INSTALL_MI_LCL_LIST : Installs header file to location that is available

for Apple internal in user level.

Locations -

$(DSTROOT)/System/Library/Frameworks/System.framework/PrivateHeaders

Definition -

INSTALL_MI_LCL_LIST = ${DATAFILES} ${PRIVATE_DATAFILES}

c. INSTALL_KF_MI_LIST : Installs header file to location that is available

to everyone for kernel extensions.

Locations -

$(DSTROOT)/System/Library/Frameworks/Kernel.framework/Headers

Definition -

INSTALL_KF_MI_LIST = ${KERNELFILES}

d. INSTALL_KF_MI_LCL_LIST : Installs header file to location that is

available for Apple internal for kernel extensions.

Locations -

$(DSTROOT)/System/Library/Frameworks/Kernel.framework/PrivateHeaders

Definition -

INSTALL_KF_MI_LCL_LIST = ${KERNELFILES} ${PRIVATE_KERNELFILES}

4) If you want to install the header file in a sub-directory of the paths

described in (1), specify the directory name using two variable

INSTALL_MI_DIR and EXPORT_MI_DIR as follows -

INSTALL_MI_DIR = dirname

EXPORT_MI_DIR = dirname

5) A single header file can exist at different locations using the steps

mentioned above. However it might not be desirable to make all the code

in the header file available at all the locations. For example, you

want to export a function only to kernel level but not user level.

You can use C language's pre-processor directive (#ifdef, #endif, #ifndef)

to control the text generated before a header file is installed. The kernel

only includes the code if the conditional macro is TRUE and strips out

code for FALSE conditions from the header file.

Some pre-defined macros and their descriptions are -

a. PRIVATE : If true, code is available to all of the xnu kernel and is

not available in kernel extensions and user level header files. The

header files installed in all the paths described above in (1) will not

have code enclosed within this macro.

b. KERNEL_PRIVATE : Same as PRIVATE

c. BSD_KERNEL_PRIVATE : If true, code is available to the xnu/bsd part of

the kernel and is not available to rest of the kernel, kernel extensions

and user level header files. The header files installed in all the

paths described above in (1) will not have code enclosed within this

macro.

d. KERNEL : If true, code is available only in kernel and kernel

extensions and is not available in user level header files. Only the

header files installed in following paths will have the code -

$(DSTROOT)/System/Library/Frameworks/Kernel.framework/Headers

$(DSTROOT)/System/Library/Frameworks/Kernel.framework/PrivateHeaders

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C. Building XNU on a Linux x32/x64 Host.

[Note: Everything beyond this point assumes that you have xnu-deps-linux installed]

1) Type the following into your command line:

make TARGET_CONFIGS="debug arm armpba8"

More work needs to be done on this. (Fixing dtrace stuff such as ctfconvert, etc)

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D. Installing XNU headers on a Linux x32/x64 Host.

1) Type the following into your command line:

make TARGET_CONFIGS="debug arm armpba8" DSTROOT="${HOME}/KernelSDK" installhdrs

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E. Installing libkmod/libkmodc++ on a Linux x32/x64 Host.

1) Type the following into your command line:

make TARGET_CONFIGS="debug arm armpba8" RC_ProjectName=libkmod DSTROOT="${HOME}/KernelSDK"