scripts/nsdeps: adjust to the format change of *.mod files

Commit 22f26f21774f ("kbuild: get rid of duplication in *.mod files")
changed the format of *.mod files to put one object per line, but missed
to adjust scripts/nsdeps.

Fixes: 22f26f21774f ("kbuild: get rid of duplication in *.mod files")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

kbuild: replace LANG=C with LC_ALL=C

LANG gives a weak default to each LC_* in case it is not explicitly
defined. LC_ALL, if set, overrides all other LC_* variables.

LANG < LC_CTYPE, LC_COLLATE, LC_MONETARY, LC_NUMERIC, ... < LC_ALL

This is why documentation such as [1] suggests to set LC_ALL in build
scripts to get the deterministic result.

LANG=C is not strong enough to override LC_* that may be set by end
users.

[1]: https://reproducible-builds.org/docs/locales/

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Reviewed-by: Matthias Maennich <maennich@google.com>
Acked-by: Matthieu Baerts <matthieu.baerts@tessares.net> (mptcp)
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

kbuild: do not use scripts/ld-version.sh for checking spatch version

scripts/ld-version.sh was, as its file name implies, originally intended
for the GNU ld version, but is (ab)used for the spatch version too.

Use 'sort -CV' for the version comparison, then coccicheck does not need
to use scripts/ld-version.sh. Fix nsdeps as well.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>

scripts: add dummy report mode to add_namespace.cocci

When running `make coccicheck` in report mode using the
add_namespace.cocci file, it will fail for files that contain
MODULE_LICENSE. Those match the replacement precondition, but spatch
errors out as virtual.ns is not set.

In order to fix that, add the virtual rule nsdeps and only do search and
replace if that rule has been explicitly requested.

In order to make spatch happy in report mode, we also need a dummy rule,
as otherwise it errors out with "No rules apply". Using a script:python
rule appears unrelated and odd, but this is the shortest I could come up
with.

Adjust scripts/nsdeps accordingly to set the nsdeps rule when run trough
`make nsdeps`.

Suggested-by: Julia Lawall <julia.lawall@inria.fr>
Fixes: c7c4e29fb5a4 ("scripts: add_namespace: Fix coccicheck failed")
Cc: YueHaibing <yuehaibing@huawei.com>
Cc: jeyu@kernel.org
Cc: cocci@systeme.lip6.fr
Cc: stable@vger.kernel.org
Signed-off-by: Matthias Maennich <maennich@google.com>
Reported-by: Shuah Khan <skhan@linuxfoundation.org>
Acked-by: Julia Lawall <julia.lawall@inria.fr>
Link: https://lore.kernel.org/r/20200604164145.173925-1-maennich@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

scripts/nsdeps: support nsdeps for external module builds

scripts/nsdeps is written to take care of only in-tree modules.
Perhaps, this is not a bug, but just a design. At least,
Documentation/core-api/symbol-namespaces.rst focuses on in-tree modules.

Having said that, some people already tried nsdeps for external modules.
So, it would be nice to support it.

Reported-by: Steve French <smfrench@gmail.com>
Reported-by: Jessica Yu <jeyu@kernel.org>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Tested-by: Jessica Yu <jeyu@kernel.org>
Acked-by: Jessica Yu <jeyu@kernel.org>
Reviewed-by: Matthias Maennich <maennich@google.com>
Tested-by: Matthias Maennich <maennich@google.com>

modpost: dump missing namespaces into a single modules.nsdeps file

The modpost, with the -d option given, generates per-module .ns_deps
files.

Kbuild generates per-module .mod files to carry module information.
This is convenient because Make handles multiple jobs in parallel
when the -j option is given.

On the other hand, the modpost always runs as a single thread.
I do not see a strong reason to produce separate .ns_deps files.

This commit changes the modpost to generate just one file,
modules.nsdeps, each line of which has the following format:

<module_name>: <list of missing namespaces>

Please note it contains *missing* namespaces instead of required ones.
So, modules.nsdeps is empty if the namespace dependency is all good.

This will work more efficiently because spatch will no longer process
already imported namespaces. I removed the '(if needed)' from the
nsdeps log since spatch is invoked only when needed.

This also solves the stale .ns_deps problem reported by Jessica Yu:

https://lkml.org/lkml/2019/10/28/467

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Tested-by: Jessica Yu <jeyu@kernel.org>
Acked-by: Jessica Yu <jeyu@kernel.org>
Reviewed-by: Matthias Maennich <maennich@google.com>
Tested-by: Matthias Maennich <maennich@google.com>

scripts/nsdeps: make sure to pass all module source files to spatch

The nsdeps script passes a list of the module source files to
generate_deps_for_ns() as a space delimited string named $mod_source_files,
which then passes it to spatch. But since $mod_source_files is not encased
in quotes, each source file in that string is treated as a separate shell
function argument (as $2, $3, $4, etc.). However, the spatch invocation
only refers to $2, so only the first file out of $mod_source_files is
processed by spatch.

This causes problems (namely, the MODULE_IMPORT_NS() statement doesn't
get inserted) when a module is composed of many source files and the
"main" module file containing the MODULE_LICENSE() statement is not the
first file listed in $mod_source_files. Fix this by encasing
$mod_source_files in quotes so that the entirety of the string is
treated as a single argument and can be referred to as $2.

In addition, put quotes in the variable assignment of mod_source_files
to prevent any shell interpretation and field splitting.

Reviewed-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Matthias Maennich <maennich@google.com>
Signed-off-by: Jessica Yu <jeyu@kernel.org>

scripts/nsdeps: use alternative sed delimiter

When doing an out of tree build with O=, the nsdeps script constructs
the absolute pathname of the module source file so that it can insert
MODULE_IMPORT_NS statements in the right place. However, ${srctree}
contains an unescaped path to the source tree, which, when used in a sed
substitution, makes sed complain:

++ sed 's/[^ ]* *//home/jeyu/jeyu-linux\/&/g'
sed: -e expression #1, char 12: unknown option to `s'

The sed substitution command 's' ends prematurely with the forward
slashes in the pathname, and sed errors out when it encounters the 'h',
which is an invalid sed substitution option. To avoid escaping forward
slashes ${srctree}, we can use '|' as an alternative delimiter for
sed instead to avoid this error.

Reviewed-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Matthias Maennich <maennich@google.com>
Tested-by: Matthias Maennich <maennich@google.com>
Signed-off-by: Jessica Yu <jeyu@kernel.org>

nsdeps: make generated patches independent of locale

scripts/nsdeps automatically generates a patch to add MODULE_IMPORT_NS
tags, and what is nicer, it sorts the lines alphabetically with the
'sort' command. However, the output from the 'sort' command depends on
locale.

For example, I got this:

$ { echo usbstorage; echo usb_storage; } | LANG=en_US.UTF-8 sort
usbstorage
usb_storage
$ { echo usbstorage; echo usb_storage; } | LANG=C sort
usb_storage
usbstorage

So, this means people might potentially send different patches.

This kind of issue was reported in the past, for example,
commit f55f2328bb28 ("kbuild: make sorting initramfs contents
independent of locale").

Adding 'LANG=C' is a conventional way of fixing when a deterministic
result is desirable.

I added 'LANG=C' very close to the 'sort' command since changing
locale affects the language of error messages etc. We should respect
users' choice as much as possible.

Reviewed-by: Matthias Maennich <maennich@google.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Jessica Yu <jeyu@kernel.org>

nsdeps: fix hashbang of scripts/nsdeps

This script does not use bash-extension. I am guessing this hashbang
was copied from scripts/coccicheck, which really uses bash-extension.

/bin/sh is enough for this script.

Reviewed-by: Matthias Maennich <maennich@google.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Jessica Yu <jeyu@kernel.org>

scripts: Coccinelle script for namespace dependencies.

A script that uses the '<module>.ns_deps' files generated by modpost to
automatically add the required symbol namespace dependencies to each
module.

Usage:
1) Move some symbols to a namespace with EXPORT_SYMBOL_NS() or define
DEFAULT_SYMBOL_NAMESPACE
2) Run 'make' (or 'make modules') and get warnings about modules not
importing that namespace.
3) Run 'make nsdeps' to automatically add required import statements
to said modules.

This makes it easer for subsystem maintainers to introduce and maintain
symbol namespaces into their codebase.

Co-developed-by: Martijn Coenen <maco@android.com>
Signed-off-by: Martijn Coenen <maco@android.com>
Acked-by: Julia Lawall <julia.lawall@lip6.fr>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Matthias Maennich <maennich@google.com>
Signed-off-by: Jessica Yu <jeyu@kernel.org>