talos-op-linux/scripts/kconfig/menu.c, branch v4.17

kconfig: Print reverse dependencies in groups

2018-03-25T17:03:58+00:00

Surprisingly or not, disabling a CONFIG option (which is assumed to be unneeded) may be not so trivial. Especially it is not trivial, when this CONFIG option is selected by a dozen of other configs. Before the moment commit 1ccb27143360 ("kconfig: make "Selected by:" and "Implied by:" readable") popped up in v4.16-rc1, it was an absolute pain to break down the "Selected by" reverse dependency expression in order to identify all those configs which select (IOW *do not allow disabling*) a certain feature (assumed to be not needed). This patch tries to make one step further by putting at users' fingertips the revdep top level OR sub-expressions grouped/clustered by the tristate value they evaluate to. This should allow the users to directly concentrate on and tackle the _active_ reverse dependencies. To give some numbers and quantify the complexity of certain reverse dependencies, assuming commit 617aebe6a97e ("Merge tag 'usercopy-v4.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux"), ARCH=arm64 and vanilla arm64 defconfig, here is the top 10 CONFIG options with the highest amount of top level "||" sub-expressions/tokens that make up the final "Selected by" reverse dependency expression. | Config | All revdep | Active revdep | |-------------------|------------|---------------| | REGMAP_I2C | 212 | 9 | | CRC32 | 167 | 25 | | FW_LOADER | 128 | 5 | | MFD_CORE | 124 | 9 | | FB_CFB_IMAGEBLIT | 114 | 2 | | FB_CFB_COPYAREA | 111 | 2 | | FB_CFB_FILLRECT | 110 | 2 | | SND_PCM | 103 | 2 | | CRYPTO_HASH | 87 | 19 | | WATCHDOG_CORE | 86 | 6 | The story behind the above is that users need to visually review/evaluate 212 expressions which *potentially* select REGMAP_I2C in order to identify the expressions which *actually* select REGMAP_I2C, for a particular ARCH and for a particular defconfig used. To make this experience smoother, change the way reverse dependencies are displayed to the user from [1] to [2]. [1] Old representation of DMA_ENGINE_RAID: Selected by: - AMCC_PPC440SPE_ADMA [=n] && DMADEVICES [=y] && (440SPe || 440SP) - BCM_SBA_RAID [=m] && DMADEVICES [=y] && (ARM64 [=y] || ... - FSL_RAID [=n] && DMADEVICES [=y] && FSL_SOC && ... - INTEL_IOATDMA [=n] && DMADEVICES [=y] && PCI [=y] && X86_64 - MV_XOR [=n] && DMADEVICES [=y] && (PLAT_ORION || ARCH_MVEBU [=y] ... - MV_XOR_V2 [=y] && DMADEVICES [=y] && ARM64 [=y] - XGENE_DMA [=n] && DMADEVICES [=y] && (ARCH_XGENE [=y] || ... - DMATEST [=n] && DMADEVICES [=y] && DMA_ENGINE [=y] [2] New representation of DMA_ENGINE_RAID: Selected by [y]: - MV_XOR_V2 [=y] && DMADEVICES [=y] && ARM64 [=y] Selected by [m]: - BCM_SBA_RAID [=m] && DMADEVICES [=y] && (ARM64 [=y] || ... Selected by [n]: - AMCC_PPC440SPE_ADMA [=n] && DMADEVICES [=y] && (440SPe || ... - FSL_RAID [=n] && DMADEVICES [=y] && FSL_SOC && ... - INTEL_IOATDMA [=n] && DMADEVICES [=y] && PCI [=y] && X86_64 - MV_XOR [=n] && DMADEVICES [=y] && (PLAT_ORION || ARCH_MVEBU [=y] ... - XGENE_DMA [=n] && DMADEVICES [=y] && (ARCH_XGENE [=y] || ... - DMATEST [=n] && DMADEVICES [=y] && DMA_ENGINE [=y] Suggested-by: Masahiro Yamada Signed-off-by: Eugeniu Rosca Reviewed-by: Petr Vorel Reviewed-by: Ulf Magnusson Signed-off-by: Masahiro Yamada

kconfig: clean-up reverse dependency help implementation

2018-03-25T17:03:57+00:00

This commit splits out the special E_OR handling ('-' instead of '||') into a dedicated helper expr_print_revdev(). Restore the original expr_print() prior to commit 1ccb27143360 ("kconfig: make "Selected by:" and "Implied by:" readable"). This makes sense because: - We need to chop those expressions only when printing the reverse dependency, and only when E_OR is encountered - Otherwise, it should be printed as before, so fall back to expr_print() This also improves the behavior; for a single line, it was previously displayed in the same line as "Selected by", like this: Selected by: A [=n] && B [=n] This will be displayed in a new line, consistently: Selected by: - A [=n] && B [=n] Signed-off-by: Masahiro Yamada Reviewed-by: Petr Vorel

kconfig: set SYMBOL_AUTO to the symbol marked with defconfig_list

2018-03-02T00:20:44+00:00

The 'defconfig_list' is a weird attribute. If the '.config' is missing, conf_read_simple() iterates over all visible defaults, then it uses the first one for which fopen() succeeds. config DEFCONFIG_LIST string depends on !UML option defconfig_list default "/lib/modules/$UNAME_RELEASE/.config" default "/etc/kernel-config" default "/boot/config-$UNAME_RELEASE" default "$ARCH_DEFCONFIG" default "arch/$ARCH/defconfig" However, like other symbols, the first visible default is always written out to the .config file. This might be different from what has been actually used. For example, on my machine, the third one "/boot/config-$UNAME_RELEASE" is opened, like follows: $ rm .config $ make oldconfig 2>/dev/null scripts/kconfig/conf --oldconfig Kconfig # # using defaults found in /boot/config-4.4.0-112-generic # * * Restart config... * * * IRQ subsystem * Expose irq internals in debugfs (GENERIC_IRQ_DEBUGFS) [N/y/?] (NEW) However, the resulted .config file contains the first one since it is visible: $ grep CONFIG_DEFCONFIG_LIST .config CONFIG_DEFCONFIG_LIST="/lib/modules/$UNAME_RELEASE/.config" In order to stop confusing people, prevent this CONFIG option from being written to the .config file. Signed-off-by: Masahiro Yamada Reviewed-by: Ulf Magnusson

kconfig: make "Selected by:" and "Implied by:" readable

2018-01-25T12:53:00+00:00

Reverse dependency expressions can get rather unwieldy, especially if a symbol is selected by more than a handful of other symbols. I.e. it's possible to have near endless expressions like: A && B && !C || D || F && (G || H) || [...] Chop these expressions into actually readable chunks: - A && B && !C - D - F && (G || H) - [...] I.e. transform the top level OR tokens into newlines and prepend each line with a minus. This makes the "Selected by:" and "Implied by:" blurb much easier to read. This is done only if there is more than one top level OR. "Depends on:" and "Range :" were deliberately left as they are. Based on idea from Paul Bolle. Suggested-by: Paul Bolle Signed-off-by: Petr Vorel Signed-off-by: Masahiro Yamada

kconfig: Clarify menu and 'if' dependency propagation

2018-01-21T18:30:09+00:00

It is not obvious that the last two cases refer to menus and ifs, respectively, in the conditional that sets 'parentdep'. Automatic submenu creation is done later, so the parent can't be a symbol here. No functional changes. Only comments added. Signed-off-by: Ulf Magnusson Signed-off-by: Masahiro Yamada

kconfig: Document 'if' flattening logic

2018-01-21T16:49:30+00:00

It is not obvious that this might refer to an 'if', making the code pretty cryptic: if (menu->list && (!menu->prompt || !menu->prompt->text)) { Kconfig keeps the 'if' menu nodes even after flattening. Reflect that in the example to be accurate. No functional changes. Only comments added. Signed-off-by: Ulf Magnusson Signed-off-by: Masahiro Yamada

kconfig: Clarify choice dependency propagation

2018-01-21T15:49:32+00:00

It's easy to miss that choices are special-cased to pass on their mode as the parent dependency. No functional changes. Only comments added. Signed-off-by: Ulf Magnusson Signed-off-by: Masahiro Yamada

kconfig: Document SYMBOL_OPTIONAL logic

2018-01-21T15:49:32+00:00

Not obvious, especially if you don't already know how choices are implemented. No functional changes. Only comments added. Signed-off-by: Ulf Magnusson Signed-off-by: Masahiro Yamada

kconfig: drop 'boolean' keyword

2018-01-21T15:49:29+00:00

No more users of this keyword. Drop it according to the notice by commit 6341e62b212a ("kconfig: use bool instead of boolean for type definition attributes"). Signed-off-by: Masahiro Yamada Acked-by: Luis R. Rodriguez

kconfig: Remove menu_end_entry()

2018-01-21T15:49:28+00:00

menu_end_entry() is empty and completely unused as far as I can tell: $ git log -G menu_end_entry --oneline a02f057 [PATCH] kconfig: improve error handling in the parser 1da177e Linux-2.6.12-rc2 Last one is the initial Git commit, where menu_end_entry() is empty as well. I couldn't find anything that redefined it on Google either. It might be a debugging helper for setting a breakpoint after each config, menuconfig, and comment is parsed. IMO it hurts more than it helps in that case by making the parsing code look more complicated at a glance than it really is, and I suspect it doesn't get used much. Tested by running the Kconfiglib test suite, which indirectly verifies that the .config files generated by the C implementation for each defconfig file in the kernel stays the same. Signed-off-by: Ulf Magnusson Signed-off-by: Masahiro Yamada