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: Masahiro 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: Masahiro 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: Masahiro 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: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Petr 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: Masahiro 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: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Ulf Magnusson <ulfalizer@gmail.com>

Recursive dependency should be detected and warned.  Test this.

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

The variable 'PYTHON' allows users to specify a proper executable
name in case the default 'python' does not work.  However, this does
not address the case where both Python 2.x and 3.x scripts are used
in one source tree.

PEP 394 (https://www.python.org/dev/peps/pep-0394/) provides a
convention for Python scripts portability.  Here is a quotation:

  In order to tolerate differences across platforms, all new code
  that needs to invoke the Python interpreter should not specify
  'python', but rather should specify either 'python2' or 'python3'.
  This distinction should be made in shebangs, when invoking from a
  shell script, when invoking via the system() call, or when invoking
  in any other context.
  One exception to this is scripts that are deliberately written to
  be source compatible with both Python 2.x and 3.x. Such scripts may
  continue to use python on their shebang line without affecting their
  portability.

To meet this requirement, this commit adds new variables 'PYTHON2'
and 'PYTHON3'.

arch/ia64/scripts/unwcheck.py is the only script that has ever used
$(PYTHON).  Recent commit bd5edbe6 ("ia64: convert unwcheck.py to
python3") converted it to be compatible with both Python 2.x and 3.x,
so this is the exceptional case where the use of 'python' is allowed.
So, I did not touch arch/ia64/Makefile.

tools/perf/Makefile.config sets PYTHON and PYTHON2 by itself, so it
is not affected by this commit.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.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: Ulf Magnusson <ulfalizer@gmail.com>
Signed-off-by: Masahiro 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: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Ulf 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: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Ulf 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: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Ulf 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: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Ulf Magnusson <ulfalizer@gmail.com>

conf() is never called for listnewconfig / olddefconfig.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Ulf 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: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Ulf 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: Ulf Magnusson <ulfalizer@gmail.com>
Signed-off-by: Masahiro 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: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Eugeniu Rosca <erosca@de.adit-jv.com>
Reviewed-by: Petr Vorel <pvorel@suse.cz>
Reviewed-by: Ulf Magnusson <ulfalizer@gmail.com>
Signed-off-by: Masahiro 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: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Petr Vorel <pvorel@suse.cz>

IMO, we should discourage '---help---' for new help texts, even in cases
where it would be consistent with other help texts in the file. This
will help if we ever want to get rid of '---help---' in the future.

Also simplify the code to only check for exactly '---help---'. Since
commit c2264564 ("kconfig: warn of unhandled characters in Kconfig
commands"), '---help---' is a proper keyword and can only appear in that
form. Prior to that commit, '---help---' working was more of a syntactic
quirk.
Signed-off-by: Ulf Magnusson <ulfalizer@gmail.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

Currently, only Kconfig symbols are checked for a missing or short help
text, and are only checked if they are defined with the 'config'
keyword.

To make the check more general, extend it to also check help texts for
choices and for symbols defined with the 'menuconfig' keyword.

This increases the accuracy of the check for symbols that would already
have been checked as well, since e.g. a 'menuconfig' symbol after a help
text will be recognized as ending the preceding symbol/choice
definition.

To increase the accuracy of the check further, also recognize 'if',
'endif', 'menu', 'endmenu', 'endchoice', and 'source' as ending a
symbol/choice definition.
Signed-off-by: Ulf Magnusson <ulfalizer@gmail.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

The check for a missing or short help text only considers symbols with a
prompt, but doesn't recognize any of the following as a prompt:

	bool 'foo'
	tristate 'foo'
	prompt "foo"
	prompt 'foo'

Make the check recognize those too.
Signed-off-by: Ulf Magnusson <ulfalizer@gmail.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

Pull x86/pti updates from Thomas Gleixner:
 "Yet another pile of melted spectrum related updates:

   - Drop native vsyscall support finally as it causes more trouble than
     benefit.

   - Make microcode loading more robust. There were a few issues
     especially related to late loading which are now surfacing because
     late loading of the IB* microcodes addressing spectre issues has
     become more widely used.

   - Simplify and robustify the syscall handling in the entry code

   - Prevent kprobes on the entry trampoline code which lead to kernel
     crashes when the probe hits before CR3 is updated

   - Don't check microcode versions when running on hypervisors as they
     are considered as lying anyway.

   - Fix the 32bit objtool build and a coment typo"

* 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/kprobes: Fix kernel crash when probing .entry_trampoline code
  x86/pti: Fix a comment typo
  x86/microcode: Synchronize late microcode loading
  x86/microcode: Request microcode on the BSP
  x86/microcode/intel: Look into the patch cache first
  x86/microcode: Do not upload microcode if CPUs are offline
  x86/microcode/intel: Writeback and invalidate caches before updating microcode
  x86/microcode/intel: Check microcode revision before updating sibling threads
  x86/microcode: Get rid of struct apply_microcode_ctx
  x86/spectre_v2: Don't check microcode versions when running under hypervisors
  x86/vsyscall/64: Drop "native" vsyscalls
  x86/entry/64/compat: Save one instruction in entry_INT80_compat()
  x86/entry: Do not special-case clone(2) in compat entry
  x86/syscalls: Use COMPAT_SYSCALL_DEFINEx() macros for x86-only compat syscalls
  x86/syscalls: Use proper syscall definition for sys_ioperm()
  x86/entry: Remove stale syscall prototype
  x86/syscalls/32: Simplify $entry == $compat entries
  objtool: Fix 32-bit build

Pull timer fix from Thomas Gleixner:
 "Just a single fix which adds a missing Kconfig dependency to avoid
  unmet dependency warnings"

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  clocksource/atmel-st: Add 'depends on HAS_IOMEM' to fix unmet dependency

Pull RAS fixes from Thomas Gleixner:
 "Two small fixes for RAS/MCE:

   - Serialize sysfs changes to avoid concurrent modificaiton of
     underlying data

   - Add microcode revision to Machine Check records. This should have
     been there forever, but now with the broken microcode versions in
     the wild it has become important"

* 'ras-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/MCE: Serialize sysfs changes
  x86/MCE: Save microcode revision in machine check records

Pull perf updates from Thomas Gleixner:
 "Another set of perf updates:

   - Fix a Skylake Uncore event format declaration

   - Prevent perf pipe mode from crahsing which was caused by a missing
     buffer allocation

   - Make the perf top popup message which tells the user that it uses
     fallback mode on older kernels a debug message.

   - Make perf context rescheduling work correcctly

   - Robustify the jump error drawing in perf browser mode so it does
     not try to create references to NULL initialized offset entries

   - Make trigger_on() robust so it does not enable the trigger before
     everything is set up correctly to handle it

   - Make perf auxtrace respect the --no-itrace option so it does not
     try to queue AUX data for decoding.

   - Prevent having different number of field separators in CVS output
     lines when a counter is not supported.

   - Make the perf kallsyms man page usage behave like it does for all
     other perf commands.

   - Synchronize the kernel headers"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/core: Fix ctx_event_type in ctx_resched()
  perf tools: Fix trigger class trigger_on()
  perf auxtrace: Prevent decoding when --no-itrace
  perf stat: Fix CVS output format for non-supported counters
  tools headers: Sync x86's cpufeatures.h
  tools headers: Sync copy of kvm UAPI headers
  perf record: Fix crash in pipe mode
  perf annotate browser: Be more robust when drawing jump arrows
  perf top: Fix annoying fallback message on older kernels
  perf kallsyms: Fix the usage on the man page
  perf/x86/intel/uncore: Fix Skylake UPI event format

Pull locking fix from Thomas Gleixner:
 "rt_mutex_futex_unlock() grew a new irq-off call site, but the function
  assumes that its always called from irq enabled context.

  Use (un)lock_irqsafe() to handle the new call site correctly"

* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  rtmutex: Make rt_mutex_futex_unlock() safe for irq-off callsites

Pull dmaengine fixes from Vinod Koul:
 "Two small fixes are for this cycle:

   - fix max_chunk_size for rcar-dmac for R-Car Gen3

   - fix clock resource of mv_xor_v2"

* tag 'dmaengine-fix-4.16-rc5' of git://git.infradead.org/users/vkoul/slave-dma:
  dmaengine: mv_xor_v2: Fix clock resource by adding a register clock
  dmaengine: rcar-dmac: fix max_chunk_size for R-Car Gen3

Pull GPIO fix from Linus Walleij:
 "This is a single GPIO fix for the v4.16 series affecting the Renesas
  driver, and fixes wakeup from external stuff"

* tag 'gpio-v4.16-3' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio:
  gpio: rcar: Use wakeup_path i.s.o. explicit clock handling

On the CP110 components which are present on the Armada 7K/8K SoC we need
to explicitly enable the clock for the registers. However it is not
needed for the AP8xx component, that's why this clock is optional.

With this patch both clock have now a name, but in order to be backward
compatible, the name of the first clock is not used. It allows to still
use this clock with a device tree using the old binding.
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

Merge tag 'kbuild-fixes-v4.16-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild fixes from Masahiro Yamada:

 - make fixdep parse kconfig.h to fix missing rebuild

 - replace hyphens with underscores in builtin DTB label names

 - fix typos

* tag 'kbuild-fixes-v4.16-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  kbuild: Handle builtin dtb file names containing hyphens
  scripts/bloat-o-meter: fix typos in help
  fixdep: do not ignore kconfig.h
  fixdep: remove some false CONFIG_ matches
  fixdep: remove stale references to uml-config.h

Pull watchdog fixes from Wim Van Sebroeck:

 - f71808e_wdt: Fix magic close handling

 - sbsa: 32-bit read fix for WCV

 - hpwdt: Remove legacy NMI sourcing

* tag 'linux-watchdog-4.16-fixes-2' of git://www.linux-watchdog.org/linux-watchdog:
  watchdog: hpwdt: Remove legacy NMI sourcing.
  watchdog: sbsa: use 32-bit read for WCV
  watchdog: f71808e_wdt: Fix magic close handling