Step 5 : Build the Kernel
=========================

.. tab-set::

   .. tab-item:: Build the Kernel

        * In this program, you are going to learn


        .. panels::
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                :column: col-lg-12 p-2
                :card: shadow

                * How to ?


.. panels::
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        Topics in this section,

                * :ref:`How to Build the Kernel <barelinux_x86-64_step4_0>`


.. _barelinux_x86-64_step4_0:

.. tab-set::

   .. tab-item:: Steps to Build the Kernel

        * Start building the kernel by running the following command:

        .. code-block:: c

                $ make

        * The process of building and compiling the Linux kernel takes some time to complete.

        * Meanwhile, you would see the following after giving make command:

        .. code-block:: c

                  SYNC    include/config/auto.conf.cmd
                  HOSTCC  scripts/kconfig/conf.o
                  HOSTLD  scripts/kconfig/conf
                  SYSHDR  arch/x86/include/generated/uapi/asm/unistd_32.h
                  SYSHDR  arch/x86/include/generated/uapi/asm/unistd_64.h
                  SYSHDR  arch/x86/include/generated/uapi/asm/unistd_x32.h
                  SYSTBL  arch/x86/include/generated/asm/syscalls_32.h
                  SYSHDR  arch/x86/include/generated/asm/unistd_32_ia32.h
                  SYSHDR  arch/x86/include/generated/asm/unistd_64_x32.h
                  SYSTBL  arch/x86/include/generated/asm/syscalls_64.h
                  HYPERCALLS arch/x86/include/generated/asm/xen-hypercalls.h
                  HOSTCC  arch/x86/tools/relocs_32.o
                  HOSTCC  arch/x86/tools/relocs_64.o
                  HOSTCC  arch/x86/tools/relocs_common.o
                  HOSTLD  arch/x86/tools/relocs
                  HOSTCC  scripts/genksyms/genksyms.o
                  YACC    scripts/genksyms/parse.tab.[ch]
                  HOSTCC  scripts/genksyms/parse.tab.o
                  LEX     scripts/genksyms/lex.lex.c
                  HOSTCC  scripts/genksyms/lex.lex.o
                  HOSTLD  scripts/genksyms/genksyms
                  HOSTCC  scripts/selinux/genheaders/genheaders
                  HOSTCC  scripts/selinux/mdp/mdp
                  HOSTCC  scripts/bin2c
                  HOSTCC  scripts/kallsyms
                  HOSTCC  scripts/sorttable
                  HOSTCC  scripts/asn1_compiler
                  HOSTCC  scripts/sign-file
                  HOSTCC  scripts/insert-sys-cert

        * If you are compiling the kernel on Ubuntu, you may receive the following error that interrupts the building process:

        .. code-block:: c

                make[1]: *** No rule to make target "debian/canonical-certs.pem", needed by "certs/x509_certificate_list".  Stop.

        * Disable the conflicting security certificates by executing the two commands below:

        .. code-block:: c

                $ scripts/config --disable SYSTEM_TRUSTED_KEYS
                $ scripts/config --disable SYSTEM_REVOCATION_KEYS


        * The commands return no output. Start the building process again with make, and press Enter repeatedly to confirm the default options for the generation of new certificates.

        .. code-block:: shell

                $ make
                  SYNC    include/config/auto.conf.cmd

                
                 Restart config...
                
                
                 Certificates for signature checking
                
                File name or PKCS#11 URI of module signing key (MODULE_SIG_KEY) [certs/signing_key.pem] certs/signing_key.pem
                Type of module signing key to be generated
                > 1. RSA (MODULE_SIG_KEY_TYPE_RSA)
                  2. ECDSA (MODULE_SIG_KEY_TYPE_ECDSA)
                choice[1-2?]: 1
                Provide system-wide ring of trusted keys (SYSTEM_TRUSTED_KEYRING) [Y/?] y
                  Additional X.509 keys for default system keyring (SYSTEM_TRUSTED_KEYS) [] (NEW)   Reserve area for inserting a certificate without recompiling (SYSTEM_EXTRA_CERTIFICATE) [Y/n/?] y
                    Number of bytes to reserve for the extra certificate (SYSTEM_EXTRA_CERTIFICATE_SIZE) [4096] 4096
                  Provide a keyring to which extra trustable keys may be added (SECONDARY_TRUSTED_KEYRING) [Y/n/?] y
                Provide system-wide ring of blacklisted keys (SYSTEM_BLACKLIST_KEYRING) [Y/n/?] y
                  Hashes to be preloaded into the system blacklist keyring (SYSTEM_BLACKLIST_HASH_LIST) []
                  Provide system-wide ring of revocation certificates (SYSTEM_REVOCATION_LIST) [Y/n/?] y
                    X.509 certificates to be preloaded into the system blacklist keyring (SYSTEM_REVOCATION_KEYS) [] (NEW)
                  Allow root to add signed blacklist keys (SYSTEM_BLACKLIST_AUTH_UPDATE) [N/y/?] n
                  CALL    scripts/checksyscalls.sh
                  CALL    scripts/atomic/check-atomics.sh
                  DESCEND objtool
                  CHK     include/generated/compile.h
                  CHK     kernel/kheaders_data.tar.xz
                  HOSTCC  certs/extract-cert
                  CERT    certs/x509_certificate_list
                  COPY    certs/x509.genkey
                  GENKEY  certs/signing_key.pem


        * Install the required modules with this command:

        .. code-block:: c

                $ sudo make modules_install

        * Finally, install the kernel by typing:

        .. code-block:: c

                $ sudo make install

        * The output shows done when finished