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.)

============================================= 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

$ make KERNEL_CONFIGS=DEBUG ARCH_CONFIGS=X86_64 all

$ 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

$ make ARCH_CONFIGS="I386 X86_64" exporthdrs all

$ 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)

============================================= 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

============================================= 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)

============================================= 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

============================================== 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"

darwin-on-arm / xnu

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headers, user-space headers, man pages,