Currently, *.mod is created as a side-effect of obj-m.

Split out *.mod as a dedicated build rule, which allows to unify
the %.c -> %.o rule, and remove the single-used-m rule.

This also makes the incremental build of allmodconfig faster because
it saves $(NM) invocation when there is no change in the module.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

The current format of *.mod is like this:

  line 1: directory path to the .ko file
  line 2: a list of objects linked into this module
  line 3: unresolved symbols (only when CONFIG_TRIM_UNUSED_KSYMS=y)

Now that *.mod and *.ko are created in the same directory, the line 1
provides no valuable information. It can be derived by replacing the
extension .mod with .ko. In fact, nobody uses the first line any more.

Cut down the first line.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

While descending directories, Kbuild produces objects for modules,
but do not link final *.ko files; it is done in the modpost.

To keep track of modules, Kbuild creates a *.mod file in $(MODVERDIR)
for every module it is building. Some post-processing steps read the
necessary information from *.mod files. This avoids descending into
directories again. This mechanism was introduced in 2003 or so.

Later, commit 551559e1 ("kbuild: implement modules.order") added
modules.order. So, we can simply read it out to know all the modules
with directory paths. This is easier than parsing the first line of
*.mod files.

$(MODVERDIR) has a flat directory structure, that is, *.mod files
are named only with base names. This is based on the assumption that
the module name is unique across the tree. This assumption is really
fragile.

Stephen Rothwell reported a race condition caused by a module name
conflict:

  https://lkml.org/lkml/2019/5/13/991



In parallel building, two different threads could write to the same
$(MODVERDIR)/*.mod simultaneously.

Non-unique module names are the source of all kind of troubles, hence
commit 3a48a919 ("kbuild: check uniqueness of module names")
introduced a new checker script.

However, it is still fragile in the build system point of view because
this race happens before scripts/modules-check.sh is invoked. If it
happens again, the modpost will emit unclear error messages.

To fix this issue completely, create *.mod with full directory path
so that two threads never attempt to write to the same file.

$(MODVERDIR) is no longer needed.

Since modules with directory paths are listed in modules.order, Kbuild
is still able to find *.mod files without additional descending.

I also killed cmd_secanalysis; scripts/mod/sumversion.c computes MD4 hash
for modules with MODULE_VERSION(). When CONFIG_DEBUG_SECTION_MISMATCH=y,
it occurs not only in the modpost stage, but also during directory
descending, where sumversion.c may parse stale *.mod files. It would emit
'No such file or directory' warning when an object consisting a module is
renamed, or when a single-obj module is turned into a multi-obj module or
vice versa.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Nicolas Pitre <nico@fluxnic.net>

Towards the goal of removing MODVERDIR aka .tmp_versions, read out
modules.order to get the list of modules to be processed. This is
simpler than parsing *.mod files in .tmp_versions.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

Towards the goal of removing MODVERDIR, read out modules.order to get
the list of modules to be processed. This is simpler than parsing *.mod
files in $(MODVERDIR).

For external modules, $(KBUILD_EXTMOD)/modules.order should be read.

I removed the single target %.ko from the top Makefile. To make sure
modpost works correctly, vmlinux and the other modules must be built.
You cannot build a particular .ko file alone.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

Towards the goal of removing MODVERDIR, read out modules.order to get
the list of modules to be signed. This is simpler than parsing *.mod
files in $(MODVERDIR).

The modules_sign target is only supported for in-kernel modules.
So, this commit does not take care of external modules.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

Towards the goal of removing MODVERDIR, read out modules.order to get
the list of modules to be installed. This is simpler than parsing *.mod
files in $(MODVERDIR).

For external modules, $(KBUILD_EXTMOD)/modules.order should be read.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

Currently, only the top-level modules.order drops duplicated entries.

The modules.order files in sub-directories potentially contain
duplication. To list out the paths of all modules, I want to use
modules.order instead of parsing *.mod files in $(MODVERDIR).

To achieve this, I want to rip off duplication from modules.order
of external modules too.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

Removing the 'kernel/' prefix will make our life easier because we can
simply do 'cat modules.order' to get all built modules with full paths.

Currently, we parse the first line of '*.mod' files in $(MODVERDIR).
Since we have duplicated functionality here, I plan to remove MODVERDIR
entirely.

In fact, modules.order is generated also for external modules in a
broken format. It adds the 'kernel/' prefix to the absolute path of
the module, like this:

  kernel//path/to/your/external/module/foo.ko

This is fine for now since modules.order is not used for external
modules. However, I want to sanitize the format everywhere towards
the goal of removing MODVERDIR.

We cannot change the format of installed module.{order,builtin}.
So, 'make modules_install' will add the 'kernel/' prefix while copying
them to $(MODLIB)/.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

Currently, $(objtree)/modules.order is touched in two places.

In the 'prepare0' rule, scripts/Makefile.build creates an empty
modules.order while processing 'obj=.'

In the 'modules' rule, the top-level Makefile overwrites it with
the correct list of modules.

While this might be a good side-effect that modules.order is made
empty every time (probably this is not intended functionality),
I personally do not like this behavior.

Create modules.order only when it is sensible to do so.

This avoids creating the following pointless files:

  scripts/basic/modules.order
  scripts/dtc/modules.order
  scripts/gcc-plugins/modules.order
  scripts/genksyms/modules.order
  scripts/mod/modules.order
  scripts/modules.order
  scripts/selinux/genheaders/modules.order
  scripts/selinux/mdp/modules.order
  scripts/selinux/modules.order

Going forward, $(objtree)/modules.order lists the modules that
was built in the last successful build.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

Use recently introduced devm_platform_ioremap_resource
helper which wraps platform_get_resource() and
devm_ioremap_resource() together. This helps produce much
cleaner code and remove local `struct resource` declaration.

Signed-off-by: Himanshu Jha <himanshujha199640@gmail.com>
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

It will be useful to control the header-test by a tristate option.

If CONFIG_FOO is a tristate option, you can write like this:

  header-test-$(CONFIG_FOO) += foo.h

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

We can re-add this whenever it is needed. At this moment, it is unused.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

Since commit 00c864f8 ("kconfig: allow all config targets to write
auto.conf if missing"), Kconfig creates include/config/auto.conf in the
defconfig stage when it is missing.

Joonas Kylmälä reported incorrect auto.conf generation under some
circumstances.

To reproduce it, apply the following diff:

|  --- a/arch/arm/configs/imx_v6_v7_defconfig
|  +++ b/arch/arm/configs/imx_v6_v7_defconfig
|  @@ -345,14 +345,7 @@ CONFIG_USB_CONFIGFS_F_MIDI=y
|   CONFIG_USB_CONFIGFS_F_HID=y
|   CONFIG_USB_CONFIGFS_F_UVC=y
|   CONFIG_USB_CONFIGFS_F_PRINTER=y
|  -CONFIG_USB_ZERO=m
|  -CONFIG_USB_AUDIO=m
|  -CONFIG_USB_ETH=m
|  -CONFIG_USB_G_NCM=m
|  -CONFIG_USB_GADGETFS=m
|  -CONFIG_USB_FUNCTIONFS=m
|  -CONFIG_USB_MASS_STORAGE=m
|  -CONFIG_USB_G_SERIAL=m
|  +CONFIG_USB_FUNCTIONFS=y
|   CONFIG_MMC=y
|   CONFIG_MMC_SDHCI=y
|   CONFIG_MMC_SDHCI_PLTFM=y

And then, run:

$ make ARCH=arm mrproper imx_v6_v7_defconfig

You will see CONFIG_USB_FUNCTIONFS=y is correctly contained in the
.config, but not in the auto.conf.

Please note drivers/usb/gadget/legacy/Kconfig is included from a choice
block in drivers/usb/gadget/Kconfig. So USB_FUNCTIONFS is a choice value.

This is probably a similar situation described in commit beaaddb6
("kconfig: tests: test defconfig when two choices interact").

When sym_calc_choice() is called, the choice symbol forgets the
SYMBOL_DEF_USER unless all of its choice values are explicitly set by
the user.

The choice symbol is given just one chance to recall it because
set_all_choice_values() is called if SYMBOL_NEED_SET_CHOICE_VALUES
is set.

When sym_calc_choice() is called again, the choice symbol forgets it
forever, since SYMBOL_NEED_SET_CHOICE_VALUES is a one-time aid.
Hence, we cannot call sym_clear_all_valid() again and again.

It is crazy to repeat set and unset of internal flags. However, we
cannot simply get rid of "sym->flags &= flags | ~SYMBOL_DEF_USER;"
Doing so would re-introduce the problem solved by commit 5d09598d
("kconfig: fix new choices being skipped upon config update").

To work around the issue, conf_write_autoconf() stopped calling
sym_clear_all_valid().

conf_write() must be changed accordingly. Currently, it clears
SYMBOL_WRITE after the symbol is written into the .config file. This
is needed to prevent it from writing the same symbol multiple times in
case the symbol is declared in two or more locations. I added the new
flag SYMBOL_WRITTEN, to track the symbols that have been written.

Anyway, this is a cheesy workaround in order to suppress the issue
as far as defconfig is concerned.

Handling of choices is totally broken. sym_clear_all_valid() is called
every time a user touches a symbol from the GUI interface. To reproduce
it, just add a new symbol drivers/usb/gadget/legacy/Kconfig, then touch
around unrelated symbols from menuconfig. USB_FUNCTIONFS will disappear
from the .config file.

I added the Fixes tag since it is more fatal than before. But, this
has been broken since long long time before, and still it is.
We should take a closer look to fix this correctly somehow.

Fixes: 00c864f8 ("kconfig: allow all config targets to write auto.conf if missing")
Cc: linux-stable <stable@vger.kernel.org> # 4.19+
Reported-by: Joonas Kylmälä <joonas.kylmala@iki.fi>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Tested-by: Joonas Kylmälä <joonas.kylmala@iki.fi>

Add helper commands and functions for finding pointers to struct device
by enumerating linux device bus/class infrastructure.  This can be used
to fetch subsystem and driver-specific structs:

  (gdb) p *$container_of($lx_device_find_by_class_name("net", "eth0"), "struct net_device", "dev")
  (gdb) p *$container_of($lx_device_find_by_bus_name("i2c", "0-004b"), "struct i2c_client", "dev")
  (gdb) p *(struct imx_port*)$lx_device_find_by_class_name("tty", "ttymxc1")->parent->driver_data

Several generic "lx-device-list" functions are included to enumerate
devices by bus and class:

  (gdb) lx-device-list-bus usb
  (gdb) lx-device-list-class
  (gdb) lx-device-list-tree &platform_bus

Similar information is available in /sys but pointer values are
deliberately hidden.

Link: http://lkml.kernel.org/r/c948628041311cbf1b9b4cff3dda7d2073cb3eaa.1561492937.git.leonard.crestez@nxp.com


Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com>
Reviewed-by: Stephen Boyd <sboyd@kernel.org>
Cc: Kieran Bingham <kbingham@kernel.org>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

This is like /sys/kernel/debug/pm/pm_genpd_summary except it's
accessible through a debugger.

This can be useful if the target crashes or hangs because power domains
were not properly enabled.

Link: http://lkml.kernel.org/r/f9ee627a0d4f94b894aa202fee8a98444049bed8.1561492937.git.leonard.crestez@nxp.com


Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com>
Reviewed-by: Stephen Boyd <sboyd@kernel.org>
Cc: Kieran Bingham <kbingham@kernel.org>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Commit d91bff3011cf ("proc/sysctl: add shared variables for range
check") adds some shared const variables to be used instead of a local
copy in each source file.  Warn when a chunk duplicates one of these
values in a ctl_table struct:

    $ scripts/checkpatch.pl 0001-test-commit.patch
    WARNING: duplicated sysctl range checking value 'zero', consider using the shared one in include/linux/sysctl.h
    #27: FILE: arch/arm/kernel/isa.c:48:
    +               .extra1         = &zero,

    WARNING: duplicated sysctl range checking value 'int_max', consider using the shared one in include/linux/sysctl.h
    #28: FILE: arch/arm/kernel/isa.c:49:
    +               .extra2         = &int_max,

    total: 0 errors, 2 warnings, 14 lines checked

Link: http://lkml.kernel.org/r/20190531131422.14970-1-mcroce@redhat.com


Signed-off-by: Matteo Croce <mcroce@redhat.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Joe Perches <joe@perches.com>
Cc: Aaron Tomlin <atomlin@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Add a command line switch --no-moderated to skip L: mailing lists marked
with 'moderated'.

Some people prefer not emailing moderated mailing lists as the
moderation time can be indeterminate and some emails can be
intentionally dropped by a moderator.

This can cause fragmentation of email threads when some are subscribed
to a moderated list but others are not and emails are dropped.

Link: http://lkml.kernel.org/r/6f23c2918ad9fc744269feb8f909bdfb105c5afc.camel@perches.com


Signed-off-by: Joe Perches <joe@perches.com>
Tested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Debian-based distributions place libc header files in a machine
specific directory (/usr/include/<libc-machine>) instead of
/usr/include/asm to support installation of the linux-libc-dev
package from multiple architectures. Move headers installed by
"make headers_install" accordingly using Debian's tuple from
dpkg-architecture (stored in debian/arch).

Signed-off-by: Cedric Hombourger <Cedric_Hombourger@mentor.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

'make olddefconfig' is non-interactive, so we can drop 'yes'.
The behavior is equivalent.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

The audience for the Kernel driver-model is clearly Kernel hackers.

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com> # ice driver changes

The gcc_plugins.txt file is already a ReST file. Move it
to the core-api book while renaming it.

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Kees Cook <keescook@chromium.org>

This patch continues 10dce8af (fs: stream_open - opener for
stream-like files so that read and write can run simultaneously without
deadlock) and c5bf68fe (*: convert stream-like files from
nonseekable_open -> stream_open) and teaches steam_open.cocci to
consider files as being stream-like not only if they have
.llseek=no_llseek, but also if they have .llseek=noop_llseek.

This is safe to do: the comment about noop_llseek says

	This is an implementation of ->llseek useable for the rare special case when
	userspace expects the seek to succeed but the (device) file is actually not
	able to perform the seek. In this case you use noop_llseek() instead of
	falling back to the default implementation of ->llseek.

and in general noop_llseek was massively added to drivers in 6038f373
(llseek: automatically add .llseek fop) when changing default for NULL .llseek
from NOP to no_llseek with the idea to avoid breaking compatibility, if
maybe some user-space program was using lseek on a device without caring
about the result, but caring if it was an error or not.

Amended semantic patch produces two changes when applied tree-wide:

        drivers/hid/hid-sensor-custom.c:690:8-24: WARNING: hid_sensor_custom_fops: .read() has stream semantic; safe to change nonseekable_open -> stream_open.
        drivers/input/mousedev.c:564:1-17: ERROR: mousedev_fops: .read() can deadlock .write(); change nonseekable_open -> stream_open to fix.

Cc: Julia Lawall <Julia.Lawall@lip6.fr>
Cc: Jan Blunck <jblunck@suse.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: Jonathan Cameron <jic23@kernel.org>
Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Cc: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Kirill Smelkov <kirr@nexedi.com>

Here are some of the more common spelling mistakes and typos that I've
found while fixing up spelling mistakes in the kernel over the past few
months.  Developers keep on coming up with more inventive ways to spell
words.

Link: http://lkml.kernel.org/r/20190618134807.9729-1-colin.king@canonical.com


Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The manpage for modprobe mentions that dashes and underscores are
treated interchangeably in module names.  The stack trace dumps seem to
print module names with underscores.  Use bash to replace _ with the
pattern [-_] so that file names with dashes or underscores can be found.

For example, this line:
[   27.919759]  hda_widget_sysfs_init+0x2b8/0x3a5 [snd_hda_core]

should find a module named snd-hda-core.ko.

Link: http://lkml.kernel.org/r/20190531205926.42474-1-evgreen@chromium.org


Signed-off-by: Evan Green <evgreen@chromium.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Acked-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Douglas Anderson <dianders@chromium.org>
Cc: Evan Green <evgreen@chromium.org>
Cc: Nicolas Boichat <drinkcat@chromium.org>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Manuel Traut <manut@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Misspelling 'prohibited' is quite common in the real world, although
surprisingly not so much in the Linux Kernel.  In addition to fixing the
typo we may as well add it to the spelling checker.

Also adding the present participle (prohibiting).

Link: http://lkml.kernel.org/r/20190514153341.22540-1-chris.paterson2@renesas.com


Fixes: 5bf2fbbe ("clk: renesas: cpg-mssr: Add r8a77470 support")
Signed-off-by: Chris Paterson <chris.paterson2@renesas.com>
Acked-by: Stephen Boyd <sboyd@kernel.org>
Acked-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The RISC-V architecture has a register named the "Supervisor Exception
Program Counter", or "sepc".  This abbreviation triggers checkpatch.pl's
misspelling detector, resulting in noise in the checkpatch output.  The
risk that this noise could cause more useful warnings to be missed seems
to outweigh the harm of an occasional misspelling of "spec".  Thus drop
the "sepc" entry from the misspelling list.

[akpm@linux-foundation.org: fix existing "sepc" instances, per Joe]
Link: http://lkml.kernel.org/r/20190518210037.13674-1-paul.walmsley@sifive.com


Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

In Chromium OS kernel builds, we split the debug information as .ko.debug
files, and that's what decode_stacktrace.sh needs to use.

Relax objfile matching rule to allow any .ko* file to be matched.

[drinkcat@chromium.org: add quotes around name pattern]
  Link: http://lkml.kernel.org/r/20190528103346.42720-1-drinkcat@chromium.org
Link: http://lkml.kernel.org/r/20190521234148.64060-1-drinkcat@chromium.org


Signed-off-by: Nicolas Boichat <drinkcat@chromium.org>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The basepath may contain special characters, which would confuse the regex
matcher.  ${var#prefix} does the right thing.

Link: http://lkml.kernel.org/r/20190518055946.181563-1-drinkcat@chromium.org


Fixes: 67a28de4 ("scripts/decode_stacktrace: only strip base path when a prefix of the path")
Signed-off-by: Nicolas Boichat <drinkcat@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

sym_is_choice(sym) has already been checked by previous if-block:

    if (sym_is_choice(sym) || (sym->flags & SYMBOL_NO_WRITE))
            continue;

Hence, the following code is redundant, and the comment is misleading:

    if (!sym_is_choice(sym))
            continue;
    /* fall through */

It always takes 'continue', never falls though.

Clean up the dead code.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

arch/mips/Makefile passes prefixes that start with '-' to cc-cross-prefix
when $(tool-archpref) evaluates to the empty string.

They are filtered-out before the $(shell ...) invocation. Otherwise,
'command -v' would be confused.

  $ command -v -linux-gcc
  bash: command: -l: invalid option
  command: usage: command [-pVv] command [arg ...]

Since commit 913ab978 ("kbuild: use more portable 'command -v' for
cc-cross-prefix"), cc-cross-prefix throws away the stderr output, so
the console is not polluted in any way.

This is not a big deal in practice, but I see a slightly better taste
in adding '--' to teach it that '-linux-gcc' is an argument instead of
a command option.

This will cause extra forking of subshell, but it will not be noticeable
performance regression.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

A missing compression utility or other errors were not picked up by make
and an empty kernel image was produced.  By removing the &&, errors will
no longer be ignored.

Signed-off-by: Harald Seiler <hws@denx.de>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

In old days, Kbuild always used an absolute path for $(srctree).

Since commit 890676c6 ("kbuild: Use relative path when building in
the source tree"), $(srctree) is '.' when O= was not passed from the
command line.

Yet, using absolute paths is useful in some cases even without O=, for
instance, to create a cscope file with absolute path tags.

'O=.' was known to work as a workaround to force Kbuild to use absolute
paths even when you are building in the source tree.

Since commit 25b146c5 ("kbuild: allow Kbuild to start from any
directory"), Kbuild is too clever to be tricked. Even if you pass 'O=.'
Kbuild notices you are building in the source tree, then use '.' for
$(srctree).

So, 'make O=. cscope' is no help to create absolute path tags.

We cannot force one or the other according to commit e93bc1a0
("Revert "kbuild: specify absolute paths for cscope""). Both of
relative path and absolute path have pros and cons.

This commit adds a new flag KBUILD_ABS_SRCTREE to allow users to
choose the absolute path for $(srctree).

'make KBUILD_ABS_SRCTREE=1 cscope' will work as a replacement of
'make O=. cscope'.

Reported-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

Commit 25b146c5 ("kbuild: allow Kbuild to start from any directory")
deprecated KBUILD_SRCTREE.

It is only used in tools/testing/selftest/ to distinguish out-of-tree
build. Replace it with a new boolean flag, building_out_of_srctree.

I also replaced the conditional ($(srctree),.) because the next commit
will allow an absolute path to be used for $(srctree) even when building
in the source tree.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

This script has no reference to ${ARCH}, ${src}, ${obj}.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

Our goal is to have more and more sub-architectures to join the
ARM multi-platform, and support them in a single configuration.

Remove the ARM SUBARCH support because it is ugly.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

In my view, most of headers can be self-contained. So, it would be
tedious to add every header to header-test-y explicitly. We usually
end up with "all headers with some exceptions".

There are two types in exceptions:

[1] headers that are never compiled as standalone units

  For examples, include/linux/compiler-gcc.h is not intended for
  direct inclusion. We should always exclude such ones.

[2] headers that are conditionally compiled as standalone units

  Some headers can be compiled only for particular architectures.
  For example, include/linux/arm-cci.h can be compiled only for
  arm/arm64 because it requires <asm/arm-cci.h> to exist.
  Clang can compile include/soc/nps/mtm.h only for arc because
  it contains an arch-specific register in inline assembler.

So, you can write Makefile like this:

  header-test-                += linux/compiler-gcc.h
  header-test-$(CONFIG_ARM)   += linux/arm-cci.h
  header-test-$(CONFIG_ARM64) += linux/arm-cci.h
  header-test-$(CONFIG_ARC)   += soc/nps/mtm.h

The new syntax header-test-pattern-y will be useful to specify
"the rest".

The typical usage is like this:

  header-test-pattern-y += */*.h

This will add all the headers in sub-directories to the test coverage,
excluding $(header-test-). In this regards, header-test-pattern-y
behaves like a weaker variant of header-test-y.

Caveat:
The patterns in header-test-pattern-y are prefixed with $(srctree)/$(src)/
but not $(objtree)/$(obj)/. Stale generated headers are often left over
when you traverse the git history without cleaning. Wildcard patterns for
$(objtree) may match to stale headers, which could fail to compile.
One pitfall is $(srctree)/$(src)/ and $(objtree)/$(obj)/ point to the
same directory for in-tree building. So, header-test-pattern-y should
be used with care since it can potentially match to stale headers.

Caveat2:
You could use wildcard for header-test-. For example,

  header-test- += asm-generic/%

... will exclude headers in asm-generic directory. Unfortunately, the
wildcard character is '%' instead of '*' here because this is evaluated
by $(filter-out ...) whereas header-test-pattern-y is evaluated by
$(wildcard ...). This is a kludge, but seems useful in some places...

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Tested-by: Jani Nikula <jani.nikula@intel.com>

header-test-y does not work with headers in sub-directories.

For example, you may want to write a Makefile, like this:

include/linux/Kbuild:

  header-test-y += mtd/nand.h

This entry will create a wrapper include/linux/mtd/nand.hdrtest.c
with the following content:

  #include "mtd/nand.h"

To make this work, we need to add $(srctree)/include/linux to the
header search path. It would be tedious to add ccflags-y.

Instead, we could change the *.hdrtest.c rule to wrap:

  #include "nand.h"

This works for in-tree build since #include "..." searches in the
relative path from the header with this directive. For O=... build,
we need to add $(srctree)/include/linux/mtd to the header search path,
which will be even more tedious.

After all, I thought it would be handier to compile headers directly
without creating wrappers.

I added a new build rule to compile %.h into %.h.s

The target is %.h.s instead of %.h.o because it is slightly faster.
Also, as for GCC, an empty assembly is smaller than an empty object.

I wrote the build rule:

  $(CC) $(c_flags) -S -o $@ -x c /dev/null -include $<

instead of:

  $(CC) $(c_flags) -S -o $@ -x c $<

Both work fine with GCC, but the latter is bad for Clang.

This comes down to the difference in the -Wunused-function policy.
GCC does not warn about unused 'static inline' functions at all.
Clang does not warn about the ones in included headers, but does
about the ones in the source. So, we should handle headers as
headers, not as source files.

In fact, this has been hidden since commit abb2ea7d ("compiler,
clang: suppress warning for unused static inline functions"), but we
should not rely on that.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Tested-by: Jani Nikula <jani.nikula@intel.com>

gcc asan instrumentation emits the following sequence to store frame pc
when the kernel is built with CONFIG_RELOCATABLE:
debug/vsprintf.s:
        .section        .data.rel.ro.local,"aw"
        .align  8
.LC3:
        .quad   .LASANPC4826@GOTOFF
.text
        .align  8
        .type   number, @function
number:
.LASANPC4826:

and in case reloc is issued for LASANPC label it also gets into .symtab
with the same address as actual function symbol:
$ nm -n vmlinux | grep 0000000001397150
0000000001397150 t .LASANPC4826
0000000001397150 t number

In the end kernel backtraces are almost unreadable:
[  143.748476] Call Trace:
[  143.748484] ([<000000002da3e62c>] .LASANPC2671+0x114/0x190)
[  143.748492]  [<000000002eca1a58>] .LASANPC2612+0x110/0x160
[  143.748502]  [<000000002de9d830>] print_address_description+0x80/0x3b0
[  143.748511]  [<000000002de9dd64>] __kasan_report+0x15c/0x1c8
[  143.748521]  [<000000002ecb56d4>] strrchr+0x34/0x60
[  143.748534]  [<000003ff800a9a40>] kasan_strings+0xb0/0x148 [test_kasan]
[  143.748547]  [<000003ff800a9bba>] kmalloc_tests_init+0xe2/0x528 [test_kasan]
[  143.748555]  [<000000002da2117c>] .LASANPC4069+0x354/0x748
[  143.748563]  [<000000002dbfbb16>] do_init_module+0x136/0x3b0
[  143.748571]  [<000000002dbff3f4>] .LASANPC3191+0x2164/0x25d0
[  143.748580]  [<000000002dbffc4c>] .LASANPC3196+0x184/0x1b8
[  143.748587]  [<000000002ecdf2ec>] system_call+0xd8/0x2d8

Since LASANPC labels are not even unique and get into .symtab only due
to relocs filter them out in kallsyms.

Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

Previously steam_open.cocci was treating only wait_event_.* - e.g.
wait_event_interruptible - as a blocking operation. However e.g.
wait_for_completion_interruptible is also blocking, and so from this
point of view it would be more logical to treat all wait_.* as a
blocking point.

The logic of this change actually came up for real when
drivers/pci/switch/switchtec.c changed from using
wait_event_interruptible to wait_for_completion_interruptible:

	https://lore.kernel.org/linux-pci/20190413170056.GA11293@deco.navytux.spb.ru/
	https://lore.kernel.org/linux-pci/20190415145456.GA15280@deco.navytux.spb.ru/
	https://lore.kernel.org/linux-pci/20190415154102.GB17661@deco.navytux.spb.ru/



For a driver that uses nonseekable_open with read/write having stream
semantic and read also calling e.g. wait_for_completion_interruptible,
running stream_open.cocci before this patch would produce:

	WARNING: <driver>_fops: .read() and .write() have stream semantic; safe to change nonseekable_open -> stream_open.

while after this patch it will report:

	ERROR: <driver>_fops: .read() can deadlock .write(); change nonseekable_open -> stream_open to fix.

Signed-off-by: Kirill Smelkov <kirr@nexedi.com>
Acked-by: Julia Lawall <julia.lawall@lip6.fr>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>