Step 5 : Build the Kernel

Build the Kernel

• In this program, you are going to learn

• How to ?

Topics in this section,

• How to Build the Kernel

Steps to Build the Kernel

• Start building the kernel by running the following command:

$ 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:

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:

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:

$ 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.

$ 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:

$ sudo make modules_install

• Finally, install the kernel by typing:

$ sudo make install

• The output shows done when finished