Linus continues to remind[1] people to stop using the BUG()-family of
functions. We should have this better documented (even if checkpatch.pl
has been warning[2] since 2015), so add more details to deprecated.rst,
as a distinct place to point people to for guidance.

[1] https://lore.kernel.org/lkml/CAHk-=whDHsbK3HTOpTF=ue_o04onRwTEaK_ZoJp_fjbqq4+=Jw@mail.gmail.com/
[2] https://git.kernel.org/linus/9d3e3c705eb395528fd8f17208c87581b134da48

Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/202003141524.59C619B51A@keescook
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/process/deprecated.rst has a lot of uses of :c:func:, which
is, well, deprecated.  Emacs query-replace-regexp to the rescue.

Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Add example of fall-through, list-ify the case ending statements, and
adjust the markup for links and readability. While here, adjust
strscpy() details to mention strscpy_pad().

Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Link: https://lore.kernel.org/r/202003041102.47A4E4B62@keescook
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Once in a while %p usage comes up, and I've needed to have a reference
to point people to. Add %p details to deprecated.rst.

Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/202003042301.F844A8C0EC@keescook
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Describe the fallthrough pseudo-keyword.

Convert the coding-style.rst example to the keyword style.
Add description and links to deprecated.rst.

Miguel Ojeda comments on the eventual [[fallthrough]] syntax:
 "Note that C17/C18 does not have [[fallthrough]].

  C++17 introduced it, as it is mentioned above. I would keep the
  __attribute__((fallthrough)) -> [[fallthrough]] change you did,
  though, since that is indeed the standard syntax (given the paragraph
  references C++17).

  I was told by Aaron Ballman (who is proposing them for C) that it is
  more or less likely that it becomes standardized in C2x. However, it
  is still not added to the draft (other attributes are already,
  though). See N2268 and N2269:

     http://www.open-std.org/jtc1/sc22/wg14/www/docs/n2268.pdf (fallthrough)
     http://www.open-std.org/jtc1/sc22/wg14/www/docs/n2269.pdf (attributes in general)"

Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Now that all the fall-through warnings have been addressed in the
kernel, enable the fall-through warning globally.

Also, update the deprecated.rst file to include implicit fall-through
as 'deprecated' so people can be pointed to a single location for
justification.

Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Marek <michal.lkml@markovi.net>
Cc: Kees Cook <keescook@chromium.org>
Cc: linux-kbuild@vger.kernel.org
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>

Translated documents:
- stable-kernel-rules.rst
- deprecated.rst
- kernel-enforcement-statement.rst
- license-rules.rst

Added document to have valid links
- netdev-FAQ.rst

Modifications to main documentation
- add label in deprecated.rst

Signed-off-by: Federico Vaga <federico.vaga@vaga.pv.it>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

As discussed in the "API replacement/deprecation" thread[1], this makes
an effort to document what things shouldn't get (re)added to the kernel,
by introducing Documentation/process/deprecated.rst.

[1] https://lists.linuxfoundation.org/pipermail/ksummit-discuss/2018-September/005282.html

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>