1. 根目录:
2. kernel
3. Makefile

#
# Makefile for the linux kernel.
#

obj-y     = fork.o exec_domain.o panic.o \
	    cpu.o exit.o softirq.o resource.o \
	    sysctl.o sysctl_binary.o capability.o ptrace.o user.o \
	    signal.o sys.o kmod.o workqueue.o pid.o task_work.o \
	    extable.o params.o \
	    kthread.o sys_ni.o nsproxy.o \
	    notifier.o ksysfs.o cred.o reboot.o \
	    async.o range.o smpboot.o

obj-$(CONFIG_MULTIUSER) += groups.o

ifdef CONFIG_FUNCTION_TRACER
# Do not trace debug files and internal ftrace files
CFLAGS_REMOVE_cgroup-debug.o = $(CC_FLAGS_FTRACE)
CFLAGS_REMOVE_irq_work.o = $(CC_FLAGS_FTRACE)
endif

# cond_syscall is currently not LTO compatible
CFLAGS_sys_ni.o = $(DISABLE_LTO)

obj-y += sched/
obj-y += locking/
obj-y += power/
obj-y += printk/
obj-y += irq/
obj-y += rcu/
obj-y += livepatch/

obj-$(CONFIG_CHECKPOINT_RESTORE) += kcmp.o
obj-$(CONFIG_FREEZER) += freezer.o
obj-$(CONFIG_PROFILING) += profile.o
obj-$(CONFIG_STACKTRACE) += stacktrace.o
obj-y += time/
obj-$(CONFIG_FUTEX) += futex.o
ifeq ($(CONFIG_COMPAT),y)
obj-$(CONFIG_FUTEX) += futex_compat.o
endif
obj-$(CONFIG_GENERIC_ISA_DMA) += dma.o
obj-$(CONFIG_SMP) += smp.o
ifneq ($(CONFIG_SMP),y)
obj-y += up.o
endif
obj-$(CONFIG_UID16) += uid16.o
obj-$(CONFIG_SYSTEM_TRUSTED_KEYRING) += system_keyring.o system_certificates.o
obj-$(CONFIG_MODULES) += module.o
obj-$(CONFIG_MODULE_SIG) += module_signing.o
obj-$(CONFIG_KALLSYMS) += kallsyms.o
obj-$(CONFIG_BSD_PROCESS_ACCT) += acct.o
obj-$(CONFIG_KEXEC) += kexec.o
obj-$(CONFIG_BACKTRACE_SELF_TEST) += backtracetest.o
obj-$(CONFIG_COMPAT) += compat.o
obj-$(CONFIG_CGROUPS) += cgroup.o
obj-$(CONFIG_CGROUP_FREEZER) += cgroup_freezer.o
obj-$(CONFIG_CPUSETS) += cpuset.o
obj-$(CONFIG_UTS_NS) += utsname.o
obj-$(CONFIG_USER_NS) += user_namespace.o
obj-$(CONFIG_PID_NS) += pid_namespace.o
obj-$(CONFIG_IKCONFIG) += configs.o
obj-$(CONFIG_SMP) += stop_machine.o
obj-$(CONFIG_KPROBES_SANITY_TEST) += test_kprobes.o
obj-$(CONFIG_AUDIT) += audit.o auditfilter.o
obj-$(CONFIG_AUDITSYSCALL) += auditsc.o
obj-$(CONFIG_AUDIT_WATCH) += audit_watch.o
obj-$(CONFIG_AUDIT_TREE) += audit_tree.o
obj-$(CONFIG_GCOV_KERNEL) += gcov/
obj-$(CONFIG_KPROBES) += kprobes.o
obj-$(CONFIG_KGDB) += debug/
obj-$(CONFIG_DETECT_HUNG_TASK) += hung_task.o
obj-$(CONFIG_LOCKUP_DETECTOR) += watchdog.o
obj-$(CONFIG_SECCOMP) += seccomp.o
obj-$(CONFIG_RELAY) += relay.o
obj-$(CONFIG_SYSCTL) += utsname_sysctl.o
obj-$(CONFIG_TASK_DELAY_ACCT) += delayacct.o
obj-$(CONFIG_TASKSTATS) += taskstats.o tsacct.o
obj-$(CONFIG_TRACEPOINTS) += tracepoint.o
obj-$(CONFIG_LATENCYTOP) += latencytop.o
obj-$(CONFIG_BINFMT_ELF) += elfcore.o
obj-$(CONFIG_COMPAT_BINFMT_ELF) += elfcore.o
obj-$(CONFIG_BINFMT_ELF_FDPIC) += elfcore.o
obj-$(CONFIG_FUNCTION_TRACER) += trace/
obj-$(CONFIG_TRACING) += trace/
obj-$(CONFIG_TRACE_CLOCK) += trace/
obj-$(CONFIG_RING_BUFFER) += trace/
obj-$(CONFIG_TRACEPOINTS) += trace/
obj-$(CONFIG_IRQ_WORK) += irq_work.o
obj-$(CONFIG_CPU_PM) += cpu_pm.o
obj-$(CONFIG_BPF) += bpf/

obj-$(CONFIG_PERF_EVENTS) += events/

obj-$(CONFIG_USER_RETURN_NOTIFIER) += user-return-notifier.o
obj-$(CONFIG_PADATA) += padata.o
obj-$(CONFIG_CRASH_DUMP) += crash_dump.o
obj-$(CONFIG_JUMP_LABEL) += jump_label.o
obj-$(CONFIG_CONTEXT_TRACKING) += context_tracking.o
obj-$(CONFIG_TORTURE_TEST) += torture.o

$(obj)/configs.o: $(obj)/config_data.h

# config_data.h contains the same information as ikconfig.h but gzipped.
# Info from config_data can be extracted from /proc/config*
targets += config_data.gz
$(obj)/config_data.gz: $(KCONFIG_CONFIG) FORCE
	$(call if_changed,gzip)

      filechk_ikconfiggz = (echo "static const char kernel_config_data[] __used = MAGIC_START"; cat $< | scripts/basic/bin2c; echo "MAGIC_END;")
targets += config_data.h
$(obj)/config_data.h: $(obj)/config_data.gz FORCE
	$(call filechk,ikconfiggz)

###############################################################################
#
# Roll all the X.509 certificates that we can find together and pull them into
# the kernel so that they get loaded into the system trusted keyring during
# boot.
#
# We look in the source root and the build root for all files whose name ends
# in ".x509".  Unfortunately, this will generate duplicate filenames, so we
# have make canonicalise the pathnames and then sort them to discard the
# duplicates.
#
###############################################################################
ifeq ($(CONFIG_SYSTEM_TRUSTED_KEYRING),y)
X509_CERTIFICATES-y := $(wildcard *.x509) $(wildcard $(srctree)/*.x509)
X509_CERTIFICATES-$(CONFIG_MODULE_SIG) += $(objtree)/signing_key.x509
X509_CERTIFICATES-raw := $(sort $(foreach CERT,$(X509_CERTIFICATES-y), \
				$(or $(realpath $(CERT)),$(CERT))))
X509_CERTIFICATES := $(subst $(realpath $(objtree))/,,$(X509_CERTIFICATES-raw))

ifeq ($(X509_CERTIFICATES),)
$(warning *** No X.509 certificates found ***)
endif

ifneq ($(wildcard $(obj)/.x509.list),)
ifneq ($(shell cat $(obj)/.x509.list),$(X509_CERTIFICATES))
$(info X.509 certificate list changed)
$(shell rm $(obj)/.x509.list)
endif
endif

kernel/system_certificates.o: $(obj)/x509_certificate_list

quiet_cmd_x509certs  = CERTS   $@
      cmd_x509certs  = cat $(X509_CERTIFICATES) /dev/null >$@ $(foreach X509,$(X509_CERTIFICATES),; $(kecho) "  - Including cert $(X509)")

targets += $(obj)/x509_certificate_list
$(obj)/x509_certificate_list: $(X509_CERTIFICATES) $(obj)/.x509.list
	$(call if_changed,x509certs)

targets += $(obj)/.x509.list
$(obj)/.x509.list:
	@echo $(X509_CERTIFICATES) >$@
endif

clean-files := x509_certificate_list .x509.list

ifeq ($(CONFIG_MODULE_SIG),y)
###############################################################################
#
# If module signing is requested, say by allyesconfig, but a key has not been
# supplied, then one will need to be generated to make sure the build does not
# fail and that the kernel may be used afterwards.
#
###############################################################################
ifndef CONFIG_MODULE_SIG_HASH
$(error Could not determine digest type to use from kernel config)
endif

signing_key.priv signing_key.x509: x509.genkey
	@echo "###"
	@echo "### Now generating an X.509 key pair to be used for signing modules."
	@echo "###"
	@echo "### If this takes a long time, you might wish to run rngd in the"
	@echo "### background to keep the supply of entropy topped up.  It"
	@echo "### needs to be run as root, and uses a hardware random"
	@echo "### number generator if one is available."
	@echo "###"
	openssl req -new -nodes -utf8 -$(CONFIG_MODULE_SIG_HASH) -days 36500 \
		-batch -x509 -config x509.genkey \
		-outform DER -out signing_key.x509 \
		-keyout signing_key.priv 2>&1
	@echo "###"
	@echo "### Key pair generated."
	@echo "###"

x509.genkey:
	@echo Generating X.509 key generation config
	@echo  >x509.genkey "[ req ]"
	@echo >>x509.genkey "default_bits = 4096"
	@echo >>x509.genkey "distinguished_name = req_distinguished_name"
	@echo >>x509.genkey "prompt = no"
	@echo >>x509.genkey "string_mask = utf8only"
	@echo >>x509.genkey "x509_extensions = myexts"
	@echo >>x509.genkey
	@echo >>x509.genkey "[ req_distinguished_name ]"
	@echo >>x509.genkey "#O = Unspecified company"
	@echo >>x509.genkey "CN = Build time autogenerated kernel key"
	@echo >>x509.genkey "#emailAddress = unspecified.user@unspecified.company"
	@echo >>x509.genkey
	@echo >>x509.genkey "[ myexts ]"
	@echo >>x509.genkey "basicConstraints=critical,CA:FALSE"
	@echo >>x509.genkey "keyUsage=digitalSignature"
	@echo >>x509.genkey "subjectKeyIdentifier=hash"
	@echo >>x509.genkey "authorityKeyIdentifier=keyid"
endif