kbuild: Show marked Kconfig fragments in "help"

Currently the Kconfig fragments in kernel/configs and arch/*/configs
that aren't used internally aren't discoverable through "make help",
which consists of hard-coded lists of config fragments. Instead, list
all the fragment targets that have a "# Help: " comment prefix so the
targets can be generated dynamically.

Add logic to the Makefile to search for and display the fragment and
comment. Add comments to fragments that are intended to be direct targets.

Signed-off-by: Kees Cook <keescook@chromium.org>
Co-developed-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

diff --git a/Makefile b/Makefile
index e21bf66..23cd62a 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -1552,7 +1552,6 @@ help:
        @echo  '  mrproper        - Remove all generated files + config + various backup files'
        @echo  '  distclean       - mrproper + remove editor backup and patch files'
        @echo  ''
-       @echo  'Configuration targets:'
        @$(MAKE) -f $(srctree)/scripts/kconfig/Makefile help
        @echo  ''
        @echo  'Other generic targets:'

diff --git a/arch/arm/configs/dram_0x00000000.config b/arch/arm/configs/dram_0x00000000.config
index db96dcb..8803a0f 100644 (file)
--- a/arch/arm/configs/dram_0x00000000.config
+++ b/arch/arm/configs/dram_0x00000000.config
@@ -1 +1,2 @@
+# Help: DRAM base at 0x00000000
 CONFIG_DRAM_BASE=0x00000000

diff --git a/arch/arm/configs/dram_0xc0000000.config b/arch/arm/configs/dram_0xc0000000.config
index 343d533..aab8f86 100644 (file)
--- a/arch/arm/configs/dram_0xc0000000.config
+++ b/arch/arm/configs/dram_0xc0000000.config
@@ -1 +1,2 @@
+# Help: DRAM base at 0xc0000000
 CONFIG_DRAM_BASE=0xc0000000

diff --git a/arch/arm/configs/dram_0xd0000000.config b/arch/arm/configs/dram_0xd0000000.config
index 61ba704..4aabce4 100644 (file)
--- a/arch/arm/configs/dram_0xd0000000.config
+++ b/arch/arm/configs/dram_0xd0000000.config
@@ -1 +1,2 @@
+# Help: DRAM base at 0xd0000000
 CONFIG_DRAM_BASE=0xd0000000

diff --git a/arch/arm/configs/lpae.config b/arch/arm/configs/lpae.config
index a6d6f7a..1ab94da 100644 (file)
--- a/arch/arm/configs/lpae.config
+++ b/arch/arm/configs/lpae.config
@@ -1,2 +1,3 @@
+# Help: Enable Large Physical Address Extension mode
 CONFIG_ARM_LPAE=y
 CONFIG_VMSPLIT_2G=y

diff --git a/arch/arm64/configs/virt.config b/arch/arm64/configs/virt.config
index 6865d54..c47c36f 100644 (file)
--- a/arch/arm64/configs/virt.config
+++ b/arch/arm64/configs/virt.config
@@ -1,3 +1,4 @@
+# Help: Virtualization guest
 #
 # Base options for platforms
 #

diff --git a/arch/powerpc/configs/disable-werror.config b/arch/powerpc/configs/disable-werror.config
index 6ea12a1..7776b91 100644 (file)
--- a/arch/powerpc/configs/disable-werror.config
+++ b/arch/powerpc/configs/disable-werror.config
@@ -1 +1,2 @@
+# Help: Disable -Werror
 CONFIG_PPC_DISABLE_WERROR=y

diff --git a/arch/powerpc/configs/security.config b/arch/powerpc/configs/security.config
index 1c91a35..0d54e29 100644 (file)
--- a/arch/powerpc/configs/security.config
+++ b/arch/powerpc/configs/security.config
@@ -1,3 +1,5 @@
+# Help: Common security options for PowerPC builds
+
 # This is the equivalent of booting with lockdown=integrity
 CONFIG_SECURITY=y
 CONFIG_SECURITYFS=y
@@ -12,4 +14,4 @@ CONFIG_INIT_ON_ALLOC_DEFAULT_ON=y
 
 # UBSAN bounds checking is very cheap and good for hardening
 CONFIG_UBSAN=y
-# CONFIG_UBSAN_MISC is not set
\ No newline at end of file
+# CONFIG_UBSAN_MISC is not set

diff --git a/arch/riscv/configs/32-bit.config b/arch/riscv/configs/32-bit.config
index f6af0f7..16ee163 100644 (file)
--- a/arch/riscv/configs/32-bit.config
+++ b/arch/riscv/configs/32-bit.config
@@ -1,3 +1,4 @@
+# Help: Build a 32-bit image
 CONFIG_ARCH_RV32I=y
 CONFIG_32BIT=y
 # CONFIG_PORTABLE is not set

diff --git a/arch/riscv/configs/64-bit.config b/arch/riscv/configs/64-bit.config
index 313edc5..d872a2d 100644 (file)
--- a/arch/riscv/configs/64-bit.config
+++ b/arch/riscv/configs/64-bit.config
@@ -1,2 +1,3 @@
+# Help: Build a 64-bit image
 CONFIG_ARCH_RV64I=y
 CONFIG_64BIT=y

diff --git a/arch/s390/configs/btf.config b/arch/s390/configs/btf.config
index 39227b4..eb7f84f 100644 (file)
--- a/arch/s390/configs/btf.config
+++ b/arch/s390/configs/btf.config
@@ -1 +1,2 @@
+# Help: Enable BTF debug info
 CONFIG_DEBUG_INFO_BTF=y

diff --git a/arch/s390/configs/kasan.config b/arch/s390/configs/kasan.config
index 700a8b2..84c2b55 100644 (file)
--- a/arch/s390/configs/kasan.config
+++ b/arch/s390/configs/kasan.config
@@ -1,3 +1,4 @@
+# Help: Enable KASan for debugging
 CONFIG_KASAN=y
 CONFIG_KASAN_INLINE=y
 CONFIG_KASAN_VMALLOC=y

diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index fdc2e3a..c4b2a8a 100644 (file)
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -335,9 +335,5 @@ define archhelp
   echo  '                        bzdisk/fdimage*/hdimage/isoimage also accept:'
   echo  '                        FDARGS="..."  arguments for the booted kernel'
   echo  '                        FDINITRD=file initrd for the booted kernel'
-  echo  ''
-  echo  '  kvm_guest.config    - Enable Kconfig items for running this kernel as a KVM guest'
-  echo  '  xen.config          - Enable Kconfig items for running this kernel as a Xen guest'
-  echo  '  x86_debug.config    - Enable tip tree debugging options for testing'
 
 endef

diff --git a/kernel/configs/debug.config b/kernel/configs/debug.config
index e8db8d9..4722b99 100644 (file)
--- a/kernel/configs/debug.config
+++ b/kernel/configs/debug.config
@@ -1,3 +1,5 @@
+# Help: Debugging for CI systems and finding regressions
+#
 # The config is based on running daily CI for enterprise Linux distros to
 # seek regressions on linux-next builds on different bare-metal and virtual
 # platforms. It can be used for example,

diff --git a/kernel/configs/kvm_guest.config b/kernel/configs/kvm_guest.config
index 208481d..d087706 100644 (file)
--- a/kernel/configs/kvm_guest.config
+++ b/kernel/configs/kvm_guest.config
@@ -1,3 +1,4 @@
+# Help: Bootable as a KVM guest
 CONFIG_NET=y
 CONFIG_NET_CORE=y
 CONFIG_NETDEVICES=y

diff --git a/kernel/configs/nopm.config b/kernel/configs/nopm.config
index 81ff078..ebfdc3d 100644 (file)
--- a/kernel/configs/nopm.config
+++ b/kernel/configs/nopm.config
@@ -1,3 +1,5 @@
+# Help: Disable Power Management
+
 CONFIG_PM=n
 CONFIG_SUSPEND=n
 CONFIG_HIBERNATION=n

diff --git a/kernel/configs/rust.config b/kernel/configs/rust.config
index 38a7c53..2c6e001 100644 (file)
--- a/kernel/configs/rust.config
+++ b/kernel/configs/rust.config
@@ -1 +1,2 @@
+# Help: Enable Rust
 CONFIG_RUST=y

diff --git a/kernel/configs/x86_debug.config b/kernel/configs/x86_debug.config
index 6fac5b4..35f4867 100644 (file)
--- a/kernel/configs/x86_debug.config
+++ b/kernel/configs/x86_debug.config
@@ -1,3 +1,4 @@
+# Help: Debugging options for tip tree testing
 CONFIG_X86_DEBUG_FPU=y
 CONFIG_LOCK_STAT=y
 CONFIG_DEBUG_VM=y

diff --git a/kernel/configs/xen.config b/kernel/configs/xen.config
index 436f806..6878b9a 100644 (file)
--- a/kernel/configs/xen.config
+++ b/kernel/configs/xen.config
@@ -1,3 +1,5 @@
+# Help: Bootable as a Xen guest
+#
 # global stuff - these enable us to allow some
 # of the not so generic stuff below for xen
 CONFIG_PARAVIRT=y

diff --git a/scripts/kconfig/Makefile b/scripts/kconfig/Makefile
index af1c961..4eee155 100644 (file)
--- a/scripts/kconfig/Makefile
+++ b/scripts/kconfig/Makefile
@@ -93,11 +93,13 @@ endif
 %_defconfig: $(obj)/conf
        $(Q)$< $(silent) --defconfig=arch/$(SRCARCH)/configs/$@ $(Kconfig)
 
-configfiles=$(wildcard $(srctree)/kernel/configs/$@ $(srctree)/arch/$(SRCARCH)/configs/$@)
+configfiles = $(wildcard $(srctree)/kernel/configs/$(1) $(srctree)/arch/$(SRCARCH)/configs/$(1))
+all-config-fragments = $(call configfiles,*.config)
+config-fragments = $(call configfiles,$@)
 
 %.config: $(obj)/conf
-       $(if $(call configfiles),, $(error No configuration exists for this target on this architecture))
-       $(Q)$(CONFIG_SHELL) $(srctree)/scripts/kconfig/merge_config.sh -m .config $(configfiles)
+       $(if $(config-fragments),, $(error $@ fragment does not exists on this architecture))
+       $(Q)$(CONFIG_SHELL) $(srctree)/scripts/kconfig/merge_config.sh -m .config $(config-fragments)
        $(Q)$(MAKE) -f $(srctree)/Makefile olddefconfig
 
 PHONY += tinyconfig
@@ -115,6 +117,7 @@ clean-files += tests/.cache
 
 # Help text used by make help
 help:
+       @echo  'Configuration targets:'
        @echo  '  config          - Update current config utilising a line-oriented program'
        @echo  '  nconfig         - Update current config utilising a ncurses menu based program'
        @echo  '  menuconfig      - Update current config utilising a menu based program'
@@ -141,6 +144,12 @@ help:
        @echo  '                    default value without prompting'
        @echo  '  tinyconfig      - Configure the tiniest possible kernel'
        @echo  '  testconfig      - Run Kconfig unit tests (requires python3 and pytest)'
+       @echo  ''
+       @echo  'Configuration topic targets:'
+       @$(foreach f, $(all-config-fragments), \
+               if help=$$(grep -m1 '^# Help: ' $(f)); then \
+                       printf '  %-25s - %s\n' '$(notdir $(f))' "$${help#*: }"; \
+               fi;)
 
 # ===========================================================================
 # object files used by all kconfig flavours