These patterns are common to host programs that require lexer and parser.
Move them to the top .gitignore.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: NFrank Rowand <frowand.list@gmail.com>

Tracking the line number by hand is error-prone since you need to
increment it in every \n matching pattern.

If '%option yylineno' is set, flex defines 'yylineno' to contain the
current line number and automatically updates it each time it reads a
\n character.  This is much more convenient although the lexer does
not initializes yylineno, so you need to set it to 1 each time you
start reading a new file, and restore it you go back to the previous
file.

I tested this with DEBUG_PARSE, and confirmed the same dump message
was produced.

I removed the perf-report option.  Otherwise, I see the following
message:
  %option yylineno entails a performance penalty ONLY on rules that
  can match newline characters
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>

Currently, the recursive inclusion is not detected when the offending
file is about to be included; it is detected the offending file is
about to include the *next* file.  This is because the detection loop
does not involve the file being included.

Do this check against the file that is about to be included so that
the recursive inclusion is detected before unneeded parsing happens.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>

As in the unit test, the error message for the recursive inclusion
looks like this:

  Kconfig.inc1:4: recursive inclusion detected. Inclusion path:
    current file : 'Kconfig.inc1'
    included from: 'Kconfig.inc3:1'
    included from: 'Kconfig.inc2:3'
    included from: 'Kconfig.inc1:4'

The 'Kconfig.inc1:4' is duplicated in the first and last lines.
Also, the single quotes do not help readability.

Change the message like follows:

  Recursive inclusion detected.
  Inclusion path:
    current file : Kconfig.inc1
    included from: Kconfig.inc3:1
    included from: Kconfig.inc2:3
    included from: Kconfig.inc1:4
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>

nconf.h includes <curses.h> and "ncurses.h", but it does not need to
include both.  Generally, it should fall back to curses.h only when
ncurses.h is not found.  But, looks like it has never happened;
these includes have been here for many years since commit 692d97c3
("kconfig: new configuration interface (nconfig)"), and nobody has
complained about hard-coding of ncurses.h .  Let's simply drop the
curses.h inclusion.

I replaced "ncurses.h" with <ncurses.h> since it is not a local file.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>

Currently, the unmet dependency warnings end up with endlessly long
expressions, most of which are false positives.

Here is test code to demonstrate how it currently works.

[Test Case]

  config DEP1
          def_bool y

  config DEP2
          bool "DEP2"

  config A
          bool "A"
          select E

  config B
          bool "B"
          depends on DEP2
          select E

  config C
          bool "C"
          depends on DEP1 && DEP2
          select E

  config D
          def_bool n
          select E

  config E
          bool
          depends on DEP1 && DEP2

[Result]

  $ make config
  scripts/kconfig/conf  --oldaskconfig Kconfig
  *
  * Linux Kernel Configuration
  *
  DEP2 (DEP2) [N/y/?] (NEW) n
  A (A) [N/y/?] (NEW) y
  warning: (A && B && D) selects E which has unmet direct
  dependencies (DEP1 && DEP2)

Here, I see some points to be improved.

First, '(A || B || D)' would make more sense than '(A && B && D)'.
I am not sure if this is intentional, but expr_simplify_unmet_dep()
turns OR expressions into AND, like follows:

        case E_OR:
                return expr_alloc_and(

Second, we see false positives.  'A' is a real unmet dependency.
'B' is false positive because 'DEP1' is fixed to 'y', and 'B' depends
on 'DEP2'.  'C' was correctly dropped by expr_simplify_unmet_dep().
'D' is also false positive because it has no chance to be enabled.
Current expr_simplify_unmet_dep() cannot avoid those false positives.

After all, I decided to use the same helpers as used for printing
reverse dependencies in the help.

With this commit, unreadable warnings (most of the reported symbols are
false positives) in the real world:

$ make ARCH=score allyesconfig
scripts/kconfig/conf  --allyesconfig Kconfig
warning: (HWSPINLOCK_QCOM && AHCI_MTK && STMMAC_PLATFORM &&
 DWMAC_IPQ806X && DWMAC_LPC18XX && DWMAC_OXNAS && DWMAC_ROCKCHIP &&
 DWMAC_SOCFPGA && DWMAC_STI && TI_CPSW && PINCTRL_GEMINI &&
 PINCTRL_OXNAS && PINCTRL_ROCKCHIP && PINCTRL_DOVE &&
 PINCTRL_ARMADA_37XX && PINCTRL_STM32 && S3C2410_WATCHDOG &&
 VIDEO_OMAP3 && VIDEO_S5P_FIMC && USB_XHCI_MTK && RTC_DRV_AT91SAM9 &&
 LPC18XX_DMAMUX && VIDEO_OMAP4 && COMMON_CLK_GEMINI &&
 COMMON_CLK_ASPEED && COMMON_CLK_NXP && COMMON_CLK_OXNAS &&
 COMMON_CLK_BOSTON && QCOM_ADSP_PIL && QCOM_Q6V5_PIL && QCOM_GSBI &&
 ATMEL_EBI && ST_IRQCHIP && RESET_IMX7 && PHY_HI6220_USB &&
 PHY_RALINK_USB && PHY_ROCKCHIP_PCIE && PHY_DA8XX_USB) selects
 MFD_SYSCON which has unmet direct dependencies (HAS_IOMEM)
warning: (PINCTRL_AT91 && PINCTRL_AT91PIO4 && PINCTRL_OXNAS &&
 PINCTRL_PISTACHIO && PINCTRL_PIC32 && PINCTRL_MESON &&
 PINCTRL_NOMADIK && PINCTRL_MTK && PINCTRL_MT7622 && GPIO_TB10X)
 selects OF_GPIO which has unmet direct dependencies (GPIOLIB && OF &&
 HAS_IOMEM)
warning: (FAULT_INJECTION_STACKTRACE_FILTER && LATENCYTOP && LOCKDEP)
 selects FRAME_POINTER which has unmet direct dependencies
 (DEBUG_KERNEL && (CRIS || M68K || FRV || UML || SUPERH || BLACKFIN ||
 MN10300 || METAG) || ARCH_WANT_FRAME_POINTERS)

will be turned into:

$ make ARCH=score allyesconfig
scripts/kconfig/conf  --allyesconfig Kconfig

WARNING: unmet direct dependencies detected for MFD_SYSCON
  Depends on [n]: HAS_IOMEM [=n]
  Selected by [y]:
  - PINCTRL_STM32 [=y] && PINCTRL [=y] && (ARCH_STM32 ||
 COMPILE_TEST [=y]) && OF [=y]
  - RTC_DRV_AT91SAM9 [=y] && RTC_CLASS [=y] && (ARCH_AT91 ||
 COMPILE_TEST [=y])
  - RESET_IMX7 [=y] && RESET_CONTROLLER [=y]
  - PHY_HI6220_USB [=y] && (ARCH_HISI && ARM64 ||
 COMPILE_TEST [=y])
  - PHY_RALINK_USB [=y] && (RALINK || COMPILE_TEST [=y])
  - PHY_ROCKCHIP_PCIE [=y] && (ARCH_ROCKCHIP && OF [=y] ||
 COMPILE_TEST [=y])

WARNING: unmet direct dependencies detected for OF_GPIO
  Depends on [n]: GPIOLIB [=y] && OF [=y] && HAS_IOMEM [=n]
  Selected by [y]:
  - PINCTRL_MTK [=y] && PINCTRL [=y] && (ARCH_MEDIATEK ||
 COMPILE_TEST [=y]) && OF [=y]
  - PINCTRL_MT7622 [=y] && PINCTRL [=y] && (ARCH_MEDIATEK ||
 COMPILE_TEST [=y]) && OF [=y] && (ARM64 || COMPILE_TEST [=y])

WARNING: unmet direct dependencies detected for FRAME_POINTER
  Depends on [n]: DEBUG_KERNEL [=y] && (CRIS || M68K || FRV || UML ||
 SUPERH || BLACKFIN || MN10300 || METAG) || ARCH_WANT_FRAME_POINTERS [=n]
  Selected by [y]:
  - LATENCYTOP [=y] && DEBUG_KERNEL [=y] && STACKTRACE_SUPPORT [=y] &&
 PROC_FS [=y] && !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND &&
 !ARC && !X86
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: NPetr Vorel <petr.vorel@gmail.com>

Commit 246cf9c2 ("kbuild: Warn on selecting symbols with unmet
direct dependencies") forcibly promoted ->dir_dep.tri to yes from mod.
So, the unmet direct dependencies of tristate symbols are not reported.

[Test Case]

  config MODULES
          def_bool y
          option modules

  config A
          def_bool y
          select B

  config B
          tristate "B"
          depends on m

This causes unmet dependency because 'B' is forced 'y' ignoring
'depends on m'.  This should be warned.

On the other hand, the following case ('B' is bool) should not be
warned, so 'depends on m' for bool symbols should be naturally treated
as 'depends on y'.

[Test Case2 (not unmet dependency)]

  config MODULES
          def_bool y
          option modules

  config A
          def_bool y
          select B

  config B
          bool "B"
          depends on m
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>

If recursive inclusion is detected, it should fail with error
messages.  Test this.

This also tests the line numbers in the error message, fixed by
commit 5ae6fcc4 ("kconfig: fix line number in recursive inclusion
error message").
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: NUlf Magnusson <ulfalizer@gmail.com>

Recursive dependency should be detected and warned.  Test this.

This indirectly tests the line number increments.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: NUlf Magnusson <ulfalizer@gmail.com>

Commit 3b9a19e0 ("kconfig: loop as long as we changed some symbols
in randconfig") fixed randconfig where a choice contains a sub-choice.
Prior to that commit, the sub-choice values were not set.

I am not sure whether this is an intended feature or just something
people discovered works, but it is used in the real world;
drivers/usb/gadget/legacy/Kconfig is source'd in a choice context,
then creates a sub-choice in it.

For the test case in this commit, there are 3 possible results.

Case 1:
  CONFIG_A=y
  # CONFIG_B is not set

Case 2:
  # CONFIG_A is not set
  CONFIG_B=y
  CONFIG_C=y
  # CONFIG_D is not set

Case 3:
  # CONFIG_A is not set
  CONFIG_B=y
  # CONFIG_C is not set
  CONFIG_D=y
  CONFIG_E=y

So, this test iterates several times, and checks if the result is
either of the three.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: NUlf Magnusson <ulfalizer@gmail.com>

Commit fbe98bb9 ("kconfig: Fix defconfig when one choice menu
selects options that another choice menu depends on") fixed defconfig
when two choices interact (i.e. calculating the visibility of a choice
requires to calculate another choice).

The test code in that commit log was based on the real world example,
and complicated.  So, I shrunk it down to the following:

defconfig.choice:
---8<---
CONFIG_CHOICE_VAL0=y
---8<---

---8<---
config MODULES
        def_bool y
        option modules

choice
        prompt "Choice"

config CHOICE_VAL0
        tristate "Choice 0"

config CHOICE_VAL1
        tristate "Choice 1"

endchoice

choice
        prompt "Another choice"
        depends on CHOICE_VAL0

config DUMMY
        bool "dummy"

endchoice
---8<---

Prior to commit fbe98bb9,

  $ scripts/kconfig/conf --defconfig=defconfig.choice Kconfig.choice

resulted in:

  CONFIG_MODULES=y
  CONFIG_CHOICE_VAL0=m
  # CONFIG_CHOICE_VAL1 is not set
  CONFIG_DUMMY=y

where the expected result would be:

  CONFIG_MODULES=y
  CONFIG_CHOICE_VAL0=y
  # CONFIG_CHOICE_VAL1 is not set
  CONFIG_DUMMY=y

Roughly, this weird behavior happened like this:

Symbols are calculated a couple of times.  First, all symbols are
calculated in conf_read().  The first 'choice' is evaluated to 'y'
due to the SYMBOL_DEF_USER flag, but sym_calc_choice() clears it
unless all of its choice values are explicitly set by the user.

conf_set_all_new_symbols() clears all SYMBOL_VALID flags.  Then, only
choices are calculated.  Here, the SYMBOL_DEF_USER for the first choice
has been forgotten, so it is evaluated to 'm'.  set_all_choice_values()
sets SYMBOL_DEF_USER again to choice symbols.

When calculating the second choice, due to 'depends on CHOICE_VAL0',
it triggers the calculation of CHOICE_VAL0.  As a result, SYMBOL_VALID
is set for CHOICE_VAL0.

Symbols except choices get the final chance of re-calculation in
conf_write().  In a normal case, CHOICE_VAL0 would be re-calculated,
then the first choice would be indirectly re-calculated with the
SYMBOL_DEF_USER which has been recalled by set_all_choice_values(),
which would be evaluated to 'y'.  But, in this case, CHOICE_VAL0 has
already been marked as SYMBOL_VALID, so this re-calculation does not
happen.  Then, =m from the conf_set_all_new_symbols() phase is written
out to the .config file.

Add a unit test for this naive case.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: NUlf Magnusson <ulfalizer@gmail.com>

If tristate choice values depend on symbols set to 'm', they should be
hidden when the choice containing them is changed from 'm' to 'y'
(i.e. exclusive choice).

This issue was fixed by commit fa64e5f6 ("kconfig/symbol.c: handle
choice_values that depend on 'm' symbols").

Add a test case to avoid regression.

For the input in this unit test, there is a room for argument if
"# CONFIG_CHOICE1 is not set" should be written to the .config file.

After commit fa64e5f6, this line was written to the .config file.

With commit cb67ab2c ("kconfig: do not write choice values when
their dependency becomes n"), it is not written now.

In this test, "# CONFIG_CHOICE1 is not set" is don't care.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: NUlf Magnusson <ulfalizer@gmail.com>

Commit cb67ab2c ("kconfig: do not write choice values when their
dependency becomes n") fixed a problem where "# CONFIG_... is not set"
for choice values are wrongly written into the .config file when they
are once visible, then become invisible later.

Add a test for this naive case.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: NUlf Magnusson <ulfalizer@gmail.com>

If new choice values are added with new dependency, and they become
visible during user configuration, oldconfig should recognize them
as (NEW), and ask the user for choice.

This issue was fixed by commit 5d09598d ("kconfig: fix new choices
being skipped upon config update").

This is a subtle corner case.  Add a test case to avoid breakage.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: NUlf Magnusson <ulfalizer@gmail.com>

If a symbols has dependency on the preceding symbol, the menu entry
should become the submenu of the preceding one, and displayed with
deeper indentation.

This is done by restructuring the menu tree in menu_finalize().
It is a bit complicated computation, so let's add a test case.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: NUlf Magnusson <ulfalizer@gmail.com>

The calculation of 'choice' is a bit complicated part in Kconfig.

The behavior of 'y' choice is intuitive.  If choice values are tristate,
the choice can be 'm' where each value can be enabled independently.
Also, if a choice is marked as 'optional', the whole choice can be
invisible.

Test basic functionality of choice.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: NUlf Magnusson <ulfalizer@gmail.com>

Many parts in Kconfig are so cryptic and need refactoring.  However,
its complexity prevents us from moving forward.  There are several
naive corner cases where it is difficult to notice breakage.  If
those are covered by unit tests, we will be able to touch the code
with more confidence.

Here is a simple test framework based on pytest.  The conftest.py
provides a fixture useful to run commands such as 'oldaskconfig' etc.
and to compare the resulted .config, stdout, stderr with expectations.

How to add test cases?
----------------------

For each test case, you should create a subdirectory under
scripts/kconfig/tests/ (so test cases are separated from each other).
Every test case directory should contain the following files:

 - __init__.py: describes test functions
 - Kconfig: the top level Kconfig file for the test

To do a useful job, test cases generally need additional data like
input .config and information about expected results.

How to run tests?
-----------------

You need python3 and pytest.  Then, run "make testconfig".  O= option
is supported.  If V=1 is given, detailed logs captured during tests
are displayed.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: NUlf Magnusson <ulfalizer@gmail.com>

The local{yes,mod}config targets currently have streamline_config.pl as
a prerequisite. This is redundant, because streamline_config.pl is a
checked-in file with no prerequisites.

Remove the prerequisite and reference streamline_config.pl directly in
the recipe of the rule instead.
Signed-off-by: NUlf Magnusson <ulfalizer@gmail.com>
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>

As commit cedd55d4 ("kconfig: Remove silentoldconfig from help
and docs; fix kconfig/conf's help") mentioned, 'silentoldconfig' is a
historical misnomer.  That commit removed it from help and docs since
it is an internal interface.  If so, it should be allowed to rename
it to something more intuitive.  'syncconfig' is the one I came up
with because it updates the .config if necessary, then synchronize
include/generated/autoconf.h and include/config/* with it.

You should not manually invoke 'silentoldcofig'.  Display warning if
used in case existing scripts are doing wrong.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: NUlf Magnusson <ulfalizer@gmail.com>

The purpose of local{yes,mod}config is to arrange the .config file
based on actually loaded modules.  It is unnecessary to update
include/generated/autoconf.h and include/config/* stuff here.
They will be updated as needed during the build.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: NUlf Magnusson <ulfalizer@gmail.com>

Historically, "make oldconfig" has changed its behavior several times,
quieter or louder.  (I attached the history below.)  Currently, it is
not as quiet as it should be.  This commit addresses it.

  Test Case
  ---------

---------------------------(Kconfig)----------------------------
menu "menu"

config FOO
        bool "foo"

menu "sub menu"

config BAR
        bool "bar"

endmenu

endmenu

menu "sibling menu"

config BAZ
        bool "baz"

endmenu
----------------------------------------------------------------

---------------------------(.config)----------------------------
CONFIG_BAR=y
CONFIG_BAZ=y
----------------------------------------------------------------

With the Kconfig and .config above, "make silentoldconfig" and
"make oldconfig" work differently, like follows:

  $ make silentoldconfig
  scripts/kconfig/conf  --silentoldconfig Kconfig
  *
  * Restart config...
  *
  *
  * menu
  *
  foo (FOO) [N/y/?] (NEW) y
  #
  # configuration written to .config
  #

  $ make oldconfig
  scripts/kconfig/conf  --oldconfig Kconfig
  *
  * Restart config...
  *
  *
  * menu
  *
  foo (FOO) [N/y/?] (NEW) y
  *
  * sub menu
  *
  bar (BAR) [Y/n/?] y
  #
  # configuration written to .config
  #

Both hide "sibling node" since it is irrelevant.  The difference is
that silentoldconfig hides "sub menu" whereas oldconfig does not.
The behavior of silentoldconfig is preferred since the "sub menu"
does not contain any new symbol.

The root cause is in conf().  There are three input modes that can
call conf(); oldaskconfig, oldconfig, and silentoldconfig.

Everytime conf() encounters a menu entry, it calls check_conf() to
check if it contains new symbols.  If no new symbol is found, the
menu is just skipped.

Currently, this happens only when input_mode == silentoldconfig.
The oldaskconfig enters into the check_conf() loop as silentoldconfig,
so oldaskconfig works likewise for the second loop or later, but it
never happens for oldconfig.  So, irrelevant sub-menus are shown for
oldconfig.

Change the test condition to "input_mode != oldaskconfig".  This is
false only for the first loop of oldaskconfig; it must ask the user
all symbols, so no need to call check_conf().

  History of oldconfig
  --------------------

[0] Originally, "make oldconfig" was as loud as "make config"  (It
    showed the entire .config file)

[1] Commit cd9140e1 ("kconfig: make oldconfig is now less chatty")
    made oldconfig quieter, but it was still less quieter than
    silentoldconfig.  (oldconfig did not hide sub-menus)

[2] Commit 204c96f6 ("kconfig: fix silentoldconfig") changed
    the input_mode of oldconfig to "ask_silent" from "ask_new".
    So, oldconfig really became as quiet as silentoldconfig.
    (oldconfig hided irrelevant sub-menus)

[3] Commit 4062f1a4 ("kconfig: use long options in conf") made
    oldconfig as loud as [0] due to misconversion.

[4] Commit 14828349 ("kconfig: fix make oldconfig") addressed
    the misconversion of [3], but it made oldconfig quieter only to
    the same level as [1], not [2].

This commit is restoring the behavior of [2].
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: NUlf Magnusson <ulfalizer@gmail.com>

check_conf() never increments conf_cnt for listnewconfig, so conf_cnt
is always zero.

In other words, conf_cnt is not zero, "input_mode != listnewconfig"
is met.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: NUlf Magnusson <ulfalizer@gmail.com>

conf() is never called for listnewconfig / olddefconfig.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: NUlf Magnusson <ulfalizer@gmail.com>

check_conf() traverses the menu tree, but it is completely no-op for
olddefconfig because the following if-else block does nothing.

    if (input_mode == listnewconfig) {
            ...
    } else if (input_mode != olddefconfig) {
            ...
    }

As the help message says, olddefconfig automatically sets new symbols
to their default value.  There is no room for manual intervention.
So, calling check_conf() for olddefconfig is odd in the first place.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: NUlf Magnusson <ulfalizer@gmail.com>

=== Background ===

 - Visible n-valued bool/tristate symbols generate a
   '# CONFIG_FOO is not set' line in the .config file. The idea is to
   remember the user selection without having to set a Makefile
   variable. Having n correspond to the variable being undefined in the
   Makefiles makes for easy CONFIG_* tests.

 - Invisible n-valued bool/tristate symbols normally do not generate a
   '# CONFIG_FOO is not set' line, because user values from .config
   files have no effect on invisible symbols anyway.

Currently, there is one exception to this rule: Any bool/tristate symbol
that gets the value n through a 'default' property generates a
'# CONFIG_FOO is not set' line, even if the symbol is invisible.

Note that this only applies to explicitly given defaults, and not when
the symbol implicitly defaults to n (like bool/tristate symbols without
'default' properties do).

This is inconsistent, and seems redundant:

  - As mentioned, the '# CONFIG_FOO is not set' won't affect the symbol
    once the .config is read back in.

  - Even if the symbol is invisible at first but becomes visible later,
    there shouldn't be any harm in recalculating the default value
    rather than viewing the '# CONFIG_FOO is not set' as a previous
    user value of n.

=== Changes ===

Change sym_calc_value() to only set SYMBOL_WRITE (write to .config) for
non-n-valued 'default' properties.

Note that SYMBOL_WRITE is always set for visible symbols regardless of whether
they have 'default' properties or not, so this change only affects invisible
symbols.

This reduces the size of the x86 .config on my system by about 1% (due
to removed '# CONFIG_FOO is not set' entries).

One side effect of (and the main motivation for) this change is making
the following two definitions behave exactly the same:

	config FOO
		bool

	config FOO
		bool
		default n

With this change, neither of these will generate a
'# CONFIG_FOO is not set' line (assuming FOO isn't selected/implied).
That might make it clearer to people that a bare 'default n' is
redundant.

This change only affects generated .config files and not autoconf.h:
autoconf.h only includes #defines for non-n bool/tristate symbols.

=== Testing ===

The following testing was done with the x86 Kconfigs:

 - .config files generated before and after the change were compared to
   verify that the only difference is some '# CONFIG_FOO is not set'
   entries disappearing. A couple of these were inspected manually, and
   most turned out to be from redundant 'default n/def_bool n'
   properties.

 - The generated include/generated/autoconf.h was compared before and
   after the change and verified to be identical.

 - As a sanity check, the same modification was done to Kconfiglib.
   The Kconfiglib test suite was then run to check for any mismatches
   against the output of the C implementation.
Signed-off-by: NUlf Magnusson <ulfalizer@gmail.com>
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>

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 1ccb2714 ("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 617aebe6 ("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: NMasahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: NEugeniu Rosca <erosca@de.adit-jv.com>
Reviewed-by: NPetr Vorel <pvorel@suse.cz>
Reviewed-by: NUlf Magnusson <ulfalizer@gmail.com>
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>

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 1ccb2714
("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: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: NPetr Vorel <pvorel@suse.cz>

Commit d3fc425e ("kbuild: make sure autoksyms.h exists early")
moved the code that touches autoksyms.h to scripts/kconfig/Makefile
with obscure reason.

From Nicolas' comment [1], he did not seem to be sure about the root
cause.

I guess I figured it out, so here is a fix-up I think is more correct.
According to the error log in the original post [2], the build failed
in scripts/mod/devicetable-offsets.c

scripts/mod/Makefile is descended from scripts/Makefile, which is
invoked from the top-level Makefile by the 'scripts' target.

To build vmlinux and/or modules, Kbuild descend into $(vmlinux-dirs).
This depends on 'prepare' and 'scripts' as follows:

  $(vmlinux-dirs): prepare scripts

Because there is no dependency between 'prepare' and 'scripts', the
parallel building can execute them simultaneously.

'prepare' depends on 'prepare1', which touched autoksyms.h, while
'scripts' descends into script/, then scripts/mod/, which needs
<generated/autoksyms.h> if CONFIG_TRIM_UNUSED_KSYMS.  It was the
reason of the race.

I am not happy to have unrelated code in the Kconfig Makefile, so
getting it back to the top Makefile.

I removed the standalone test target because I want to use it to
create an empty autoksyms.h file.  Here is a little improvement;
unnecessary autoksyms.h is not created when CONFIG_TRIM_UNUSED_KSYMS
is disabled.

[1] https://lkml.org/lkml/2016/11/30/734
[2] https://lkml.org/lkml/2016/11/30/531Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: NNicolas Pitre <nico@linaro.org>

When recursive inclusion is detected, the line number of the last
'included from:' is wrong.

[Test Case]

Kconfig:
  -------->8--------
  source "Kconfig2"
  -------->8--------

Kconfig2:
  -------->8--------
  source "Kconfig3"
  -------->8--------

Kconfig3:
  -------->8--------
  source "Kconfig"
  -------->8--------

[Result]

  $ make allyesconfig
  scripts/kconfig/conf  --allyesconfig Kconfig
  Kconfig:1: recursive inclusion detected. Inclusion path:
    current file : 'Kconfig'
    included from: 'Kconfig3:1'
    included from: 'Kconfig2:1'
    included from: 'Kconfig:3'
  scripts/kconfig/Makefile:89: recipe for target 'allyesconfig' failed
  make[1]: *** [allyesconfig] Error 1
  Makefile:512: recipe for target 'allyesconfig' failed
  make: *** [allyesconfig] Error 2

where we expect

    current file : 'Kconfig'
    included from: 'Kconfig3:1'
    included from: 'Kconfig2:1'
    included from: 'Kconfig:1'

The 'iter->lineno+1' in the second fpinrtf() should be 'iter->lineno-1'.
I refactored the code to merge the two fprintf() calls.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: NUlf Magnusson <ulfalizer@gmail.com>

The package name is ncurses-devel for Redhat based distros
and libncurses-dev for Debian based distros.
Signed-off-by: NArvind Prasanna <arvindprasanna@gmail.com>
Acked-by: NRandy Dunlap <rdunlap@infradead.org>
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>

The named choice is not used in the kernel tree, but if it were used,
it would not be freed.

The intention of the named choice can be seen in the log of
commit 5a1aa8a1 ("kconfig: add named choice group").
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: NUlf Magnusson <ulfalizer@gmail.com>

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: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: NUlf Magnusson <ulfalizer@gmail.com>

We already have xmalloc(), xcalloc(), and xrealloc(().  Add xstrdup()
as well to save tedious error handling.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>

This function returns realloc'ed memory, so the returned pointer
must be passed to free() when done.  So, 'const' qualifier is odd.
It is allowed to modify the expanded string.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>

We already have xmalloc(), xcalloc().  Add xrealloc() as well
to save tedious error handling.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>

These messages should be directed to stderr.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: NUlf Magnusson <ulfalizer@gmail.com>

If stdio is not tty, conf_askvalue() puts additional new line to
prevent prompts from being concatenated into a single line.  This
care is missing in conf_choice(), so a 'choice' prompt and the next
prompt are shown in the same line.

Move the code into xfgets() to cater to all cases.  To improve this
more, let's echo stdin to stdout.  This clarifies what keys were
input from stdio and the stdout looks like as if it were from tty.

I removed the isatty(2) check since stderr is unrelated here.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: NUlf Magnusson <ulfalizer@gmail.com>

Except silentoldconfig, valid_stdin is 1, so check_stdin() is no-op.

oldconfig and silentoldconfig work almost in the same way except that
the latter generates additional files under include/.  Both ask users
for input for new symbols.

I do not know why only silentoldconfig requires stdio be tty.

  $ rm -f .config; touch .config
  $ yes "" | make oldconfig > stdout
  $ rm -f .config; touch .config
  $ yes "" | make silentoldconfig > stdout
  make[1]: *** [silentoldconfig] Error 1
  make: *** [silentoldconfig] Error 2
  $ tail -n 4 stdout
  Console input/output is redirected. Run 'make oldconfig' to update configuration.

  scripts/kconfig/Makefile:40: recipe for target 'silentoldconfig' failed
  Makefile:507: recipe for target 'silentoldconfig' failed

Redirection is useful, for example, for testing where we want to give
particular key inputs from a test file, then check the result.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: NUlf Magnusson <ulfalizer@gmail.com>

I could not figure out why this pattern should be ignored.
Checking commit 1e65174a ("Add some basic .gitignore files")
did not help.

Let's remove this pattern, then see if it is really needed.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: NUlf Magnusson <ulfalizer@gmail.com>

'make config', 'make oldconfig', etc. always receive '?' as a valid
input and show useful information even if no help text is available.

------------------------>8------------------------
foo (FOO) [N/y] (NEW) ?

There is no help available for this option.
Symbol: FOO [=n]
Type  : bool
Prompt: foo
  Defined at Kconfig:1
------------------------>8------------------------

However, '?' is not shown in the prompt if its help text is missing.
Let's show '?' all the time so that the prompt and the behavior match.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: NUlf Magnusson <ulfalizer@gmail.com>