core/pkg-kconfig: Use olddefconfig when available

Using 'yes "" | make oldconfig' to regenerate a .config file from an existing defconfig does not work reliably in all cases. Specifically, it does not work well with tristate choice entries.

The correct way to do it is to use 'make olddefconfig', but this target is not supported in projects that use an old version of kconfig. As most projects do not use tristate entries, there is no need for them to upgrade.

'oldnoconfig' is an alias for 'olddefconfig', but it also is the only name for this target between Linux versions 2.6.36 and 3.6.

Check which targets are supported by the current project, and use the appropriate method to regenerate the .config file.

Signed-off-by Romain Izard <[email protected]>

Reviewed-by "Yann E. MORIN" <[email protected]>

---
Changelog:
v1: New patch
v2: Use oldnoconfig instead of olddefconfig
Fix silent mode
Change the pattern in both places where it is used Use a macro to avoid redundancy
v3: Do not use $(call ...)

    Use the $(2)_KCONFIG_MAKE variable

v4: No change
v5: Detect available methods and use the most recent one
v6: Remove colon from matched rule names

 package/pkg-kconfig.mk | 25 +++++++++++++++++++++----
 1 file changed, 21 insertions(+), 4 deletions(-)

package/pkg-kconfig.mk +0 -0

index 4033915..478f5bb 100644

package/pkg-kconfig.mk +17 -4

+# The correct way to regenerate a .config file is to use 'make olddefconfig'.
+# For historical reasons, the target name is 'oldnoconfig' between Linux kernel
+# versions 2.6.36 and 3.6, and remains as an alias in later versions.
+# In older versions, and in some other projects that use kconfig, the target is
+# not supported at all, and we use 'yes "" | make oldconfig' as a fallback
+# only, as this can fail in complex cases.
+define $(2)_REGEN_DOT_CONFIG
+	$$(if $$(filter olddefconfig,$$($(2)_KCONFIG_RULES)),
+		$$(Q)$$($(2)_KCONFIG_MAKE) olddefconfig,
+		$$(if $$(filter oldnoconfig,$$($(2)_KCONFIG_RULES)),
+			$$(Q)$$($(2)_KCONFIG_MAKE) oldnoconfig,
+			$$(Q)(yes "" | $$($(2)_KCONFIG_MAKE) oldconfig)))
+endef
+
 # The specified source configuration file and any additional configuration file
 # fragments are merged together to .config, after the package has been patched.
 # Since the file could be a defconfig file it needs to be expanded to a
-# full .config first. We use 'make oldconfig' because this can be safely
-# done even when the package does not support defconfigs.
+# full .config first.
 $$($(2)_DIR)/.config: $$($(2)_KCONFIG_FILE) $$($(2)_KCONFIG_FRAGMENT_FILES)
 	$$(Q)$$(if $$($(2)_KCONFIG_DEFCONFIG), \
 		$$($(2)_KCONFIG_MAKE) $$($(2)_KCONFIG_DEFCONFIG), \
 		cp $$($(2)_KCONFIG_FILE) $$(@))
 	$$(Q)support/kconfig/merge_config.sh -m -O $$(@D) \
 		$$(@) $$($(2)_KCONFIG_FRAGMENT_FILES)
-	$$(Q)yes "" | $$($(2)_KCONFIG_MAKE) oldconfig
+	$$($(2)_REGEN_DOT_CONFIG)
 
 # If _KCONFIG_FILE or _KCONFIG_FRAGMENT_FILES exists, this dependency is
 # already implied, but if we only have a _KCONFIG_DEFCONFIG we have to add

@@ -82,7 +99,7 @@ $$($(2)_DIR)/.config: | $(1)-patch
 # The exact rules are specified by the package .mk file.
 define $(2)_FIXUP_DOT_CONFIG
 	$$($(2)_KCONFIG_FIXUP_CMDS)
-	$$(Q)yes "" | $$($(2)_KCONFIG_MAKE) oldconfig
+	$$($(2)_REGEN_DOT_CONFIG)
 	$$(Q)touch $$($(2)_DIR)/.stamp_kconfig_fixup_done
 endef
 

Signature · 1 line

2.5.0

Ok, so... Well... Err...

Could you respin v4 of the patch, the one that used something like:

    make oldnoconfig || (yes "" |make oldconfig)

please? ;-)

OK, what's wrong with my proposal? It works in an unconfigured tree. But as soon as the tree is configured, it breaks, notably with older kernels, like 3.0.

    $ cd linux-3.0
    $ make -qpn oldefconfig 2>/dev/null |grep olddefconfig
    [nothing]
    $ touch .config
    $ make -qpn oldefconfig 2>/dev/null |grep olddefconfig
    olddefconfig: scripts_basic outputmakefile FORCE

But 3.0 does not have olddefconfig. It's jsut the %config generic rule kicking in. So we'd believe there would be support for olddefconfig (or oldnoconfig) when there isn't.

So, I have to apologise for the delusion. Your v4 is the best we can do.

2016-04-22 0:47 GMT+02:00 Yann E. MORIN <[email protected]>:

Quoted 20 lines

Ok, so... Well... Err...

Could you respin v4 of the patch, the one that used something like:

    make oldnoconfig || (yes "" |make oldconfig)

please? ;-)

OK, what's wrong with my proposal? It works in an unconfigured tree. But as soon as the tree is configured, it breaks, notably with older kernels, like 3.0.

    $ cd linux-3.0
    $ make -qpn oldefconfig 2>/dev/null |grep olddefconfig
    [nothing]
    $ touch .config
    $ make -qpn oldefconfig 2>/dev/null |grep olddefconfig
    olddefconfig: scripts_basic outputmakefile FORCE

Quoted 6 lines

But 3.0 does not have olddefconfig. It's jsut the %config generic rule kicking in. So we'd believe there would be support for olddefconfig (or oldnoconfig) when there isn't.

So, I have to apologise for the delusion. Your v4 is the best we can do.

After some more testing, I believe it should work. I've tested the following command on the latest commit for all stable branches since 2.6.11, and I can reliably detect which targets are supported. Moreover, I have the same output whether I touched .config or not.

make -pn O=dir config 2>/dev/null | grep -oE '^old(no|def)config:'

I believe the problem with your tests is that you try to use both '-q' and '-n', while GNU Make's manual states (Chapter 9.3, Instead of executing recipes) that:

"It is an error to use more than one of these three flags [-t -q -n] in the same invocation of 'make'."

Yann, all,

2016-04-22 0:47 GMT+02:00 Yann E. MORIN <[email protected]>:

Quoted 20 lines

Ok, so... Well... Err...

Could you respin v4 of the patch, the one that used something like:

     make oldnoconfig || (yes "" |make oldconfig)

please? ;-)

OK, what's wrong with my proposal? It works in an unconfigured tree. But as soon as the tree is configured, it breaks, notably with older kernels, like 3.0.

     $ cd linux-3.0
     $ make -qpn oldefconfig 2>/dev/null |grep olddefconfig
     [nothing]
     $ touch .config
     $ make -qpn oldefconfig 2>/dev/null |grep olddefconfig
     olddefconfig: scripts_basic outputmakefile FORCE

Quoted 6 lines

But 3.0 does not have olddefconfig. It's jsut the %config generic rule kicking in. So we'd believe there would be support for olddefconfig (or oldnoconfig) when there isn't.

So, I have to apologise for the delusion. Your v4 is the best we can do.

After some more testing, I believe it should work. I've tested the following command on the latest commit for all stable branches since 2.6.11, and I can reliably detect which targets are supported. Moreover, I have the same output whether I touched .config or not.

make -pn O=dir config 2>/dev/null | grep -oE '^old(no|def)config:'

I believe the problem with your tests is that you try to use both '-q' and '-n', while GNU Make's manual states (Chapter 9.3, Instead of executing recipes) that:

"It is an error to use more than one of these three flags [-t -q -n] in the same invocation of 'make'."