[PATCH 12/14] doc-rst: add ABI documentation to the admin-guide book

[Mauro Carvalho Chehab <mchehab+samsung@kernel.org>]

From: Mauro Carvalho Chehab <mchehab@s-opensource.com>

As we don't want a generic Sphinx extension to execute commands,
change the one proposed to Markus to call the abi_book.pl
script.

Use a script to parse the Documentation/ABI directory and output
it at the admin-guide.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
---
 Documentation/admin-guide/abi-obsolete.rst |  10 ++
 Documentation/admin-guide/abi-removed.rst  |   4 +
 Documentation/admin-guide/abi-stable.rst   |  13 ++
 Documentation/admin-guide/abi-testing.rst  |  19 +++
 Documentation/admin-guide/abi.rst          |  11 ++
 Documentation/admin-guide/index.rst        |   1 +
 Documentation/conf.py                      |   2 +-
 Documentation/sphinx/kernel_abi.py         | 155 +++++++++++++++++++++
 8 files changed, 214 insertions(+), 1 deletion(-)
 create mode 100644 Documentation/admin-guide/abi-obsolete.rst
 create mode 100644 Documentation/admin-guide/abi-removed.rst
 create mode 100644 Documentation/admin-guide/abi-stable.rst
 create mode 100644 Documentation/admin-guide/abi-testing.rst
 create mode 100644 Documentation/admin-guide/abi.rst
 create mode 100644 Documentation/sphinx/kernel_abi.py

diff --git a/Documentation/admin-guide/abi-obsolete.rst b/Documentation/admin-guide/abi-obsolete.rst
new file mode 100644
index 000000000000..cda9168445a5
--- /dev/null
+++ b/Documentation/admin-guide/abi-obsolete.rst
@@ -0,0 +1,10 @@
+ABI obsolete symbols
+====================
+
+Documents interfaces that are still remaining in the kernel, but are
+marked to be removed at some later point in time.
+
+The description of the interface will document the reason why it is
+obsolete and when it can be expected to be removed.
+
+.. kernel-abi:: $srctree/Documentation/ABI/obsolete
diff --git a/Documentation/admin-guide/abi-removed.rst b/Documentation/admin-guide/abi-removed.rst
new file mode 100644
index 000000000000..497978fc9632
--- /dev/null
+++ b/Documentation/admin-guide/abi-removed.rst
@@ -0,0 +1,4 @@
+ABI removed symbols
+===================
+
+.. kernel-abi:: $srctree/Documentation/ABI/removed
diff --git a/Documentation/admin-guide/abi-stable.rst b/Documentation/admin-guide/abi-stable.rst
new file mode 100644
index 000000000000..7495d7a35048
--- /dev/null
+++ b/Documentation/admin-guide/abi-stable.rst
@@ -0,0 +1,13 @@
+ABI stable symbols
+==================
+
+Documents the interfaces that the developer has defined to be stable.
+
+Userspace programs are free to use these interfaces with no
+restrictions, and backward compatibility for them will be guaranteed
+for at least 2 years.
+
+Most interfaces (like syscalls) are expected to never change and always
+be available.
+
+.. kernel-abi:: $srctree/Documentation/ABI/stable
diff --git a/Documentation/admin-guide/abi-testing.rst b/Documentation/admin-guide/abi-testing.rst
new file mode 100644
index 000000000000..5c886fc50b9e
--- /dev/null
+++ b/Documentation/admin-guide/abi-testing.rst
@@ -0,0 +1,19 @@
+ABI testing symbols
+===================
+
+Documents interfaces that are felt to be stable,
+as the main development of this interface has been completed.
+
+The interface can be changed to add new features, but the
+current interface will not break by doing this, unless grave
+errors or security problems are found in them.
+
+Userspace programs can start to rely on these interfaces, but they must
+be aware of changes that can occur before these interfaces move to
+be marked stable.
+
+Programs that use these interfaces are strongly encouraged to add their
+name to the description of these interfaces, so that the kernel
+developers can easily notify them if any changes occur.
+
+.. kernel-abi:: $srctree/Documentation/ABI/testing
diff --git a/Documentation/admin-guide/abi.rst b/Documentation/admin-guide/abi.rst
new file mode 100644
index 000000000000..3b9645c77469
--- /dev/null
+++ b/Documentation/admin-guide/abi.rst
@@ -0,0 +1,11 @@
+=====================
+Linux ABI description
+=====================
+
+.. toctree::
+   :maxdepth: 1
+
+   abi-stable
+   abi-testing
+   abi-obsolete
+   abi-removed
diff --git a/Documentation/admin-guide/index.rst b/Documentation/admin-guide/index.rst
index 8001917ee012..20c3020fd73c 100644
--- a/Documentation/admin-guide/index.rst
+++ b/Documentation/admin-guide/index.rst
@@ -16,6 +16,7 @@ etc.
    README
    kernel-parameters
    devices
+   abi
 
 This section describes CPU vulnerabilities and their mitigations.
 
diff --git a/Documentation/conf.py b/Documentation/conf.py
index 7ace3f8852bd..598256fb5c98 100644
--- a/Documentation/conf.py
+++ b/Documentation/conf.py
@@ -34,7 +34,7 @@ needs_sphinx = '1.3'
 # Add any Sphinx extension module names here, as strings. They can be
 # extensions coming with Sphinx (named 'sphinx.ext.*') or your custom
 # ones.
-extensions = ['kerneldoc', 'rstFlatTable', 'kernel_include', 'cdomain', 'kfigure', 'sphinx.ext.ifconfig']
+extensions = ['kerneldoc', 'rstFlatTable', 'kernel_include', 'cdomain', 'kfigure', 'sphinx.ext.ifconfig', 'kernel_abi']
 
 # The name of the math extension changed on Sphinx 1.4
 if (major == 1 and minor > 3) or (major > 1):
diff --git a/Documentation/sphinx/kernel_abi.py b/Documentation/sphinx/kernel_abi.py
new file mode 100644
index 000000000000..32ce90775d96
--- /dev/null
+++ b/Documentation/sphinx/kernel_abi.py
@@ -0,0 +1,155 @@
+# -*- coding: utf-8; mode: python -*-
+u"""
+    kernel-abi
+    ~~~~~~~~~~
+
+    Implementation of the ``kernel-abi`` reST-directive.
+
+    :copyright:  Copyright (C) 2016  Markus Heiser
+    :copyright:  Copyright (C) 2016  Mauro Carvalho Chehab
+    :license:    GPL Version 2, June 1991 see Linux/COPYING for details.
+
+    The ``kernel-abi`` (:py:class:`KernelCmd`) directive calls the
+    scripts/get_abi.pl script to parse the Kernel ABI files.
+
+    Overview of directive's argument and options.
+
+    .. code-block:: rst
+
+        .. kernel-abi:: <ABI directory location>
+            :debug:
+
+    The argument ``<ABI directory location>`` is required. It contains the
+    location of the ABI files to be parsed.
+
+    ``debug``
+      Inserts a code-block with the *raw* reST. Sometimes it is helpful to see
+      what reST is generated.
+
+"""
+
+import sys
+import os
+from os import path
+import subprocess
+
+from sphinx.ext.autodoc import AutodocReporter
+
+from docutils import nodes
+from docutils.parsers.rst import Directive, directives
+from docutils.statemachine import ViewList
+from docutils.utils.error_reporting import ErrorString
+
+
+__version__  = '1.0'
+
+# We can't assume that six is installed
+PY3 = sys.version_info[0] == 3
+PY2 = sys.version_info[0] == 2
+if PY3:
+    # pylint: disable=C0103, W0622
+    unicode     = str
+    basestring  = str
+
+def setup(app):
+
+    app.add_directive("kernel-abi", KernelCmd)
+    return dict(
+        version = __version__
+        , parallel_read_safe = True
+        , parallel_write_safe = True
+    )
+
+class KernelCmd(Directive):
+
+    u"""KernelABI (``kernel-abi``) directive"""
+
+    required_arguments = 1
+    optional_arguments = 0
+    has_content = False
+    final_argument_whitespace = True
+
+    option_spec = {
+        "debug"     : directives.flag
+    }
+
+    def warn(self, message, **replace):
+        replace["fname"]   = self.state.document.current_source
+        replace["line_no"] = replace.get("line_no", self.lineno)
+        message = ("%(fname)s:%(line_no)s: [kernel-abi WARN] : " + message) % replace
+        self.state.document.settings.env.app.warn(message, prefix="")
+
+    def run(self):
+
+        doc = self.state.document
+        if not doc.settings.file_insertion_enabled:
+            raise self.warning("docutils: file insertion disabled")
+
+        env = doc.settings.env
+        cwd = path.dirname(doc.current_source)
+        cmd = "get_abi.pl rest --dir "
+        cmd += self.arguments[0]
+
+        srctree = path.abspath(os.environ["srctree"])
+
+        fname = cmd
+
+        # extend PATH with $(srctree)/scripts
+        path_env = os.pathsep.join([
+            srctree + os.sep + "scripts",
+            os.environ["PATH"]
+        ])
+        shell_env = os.environ.copy()
+        shell_env["PATH"]    = path_env
+        shell_env["srctree"] = srctree
+
+        lines = self.runCmd(cmd, shell=True, cwd=cwd, env=shell_env)
+        nodeList = self.nestedParse(lines, fname)
+        return nodeList
+
+    def runCmd(self, cmd, **kwargs):
+        u"""Run command ``cmd`` and return it's stdout as unicode."""
+
+        try:
+            proc = subprocess.Popen(
+                cmd
+                , stdout = subprocess.PIPE
+                , stderr = subprocess.PIPE
+                , universal_newlines = True
+                , **kwargs
+            )
+            out, err = proc.communicate()
+            if err:
+                self.warn(err)
+            if proc.returncode != 0:
+                raise self.severe(
+                    u"command '%s' failed with return code %d"
+                    % (cmd, proc.returncode)
+                )
+        except OSError as exc:
+            raise self.severe(u"problems with '%s' directive: %s."
+                              % (self.name, ErrorString(exc)))
+        return unicode(out)
+
+    def nestedParse(self, lines, fname):
+        content = ViewList()
+        node    = nodes.section()
+
+        if "debug" in self.options:
+            code_block = "\n\n.. code-block:: rst\n    :linenos:\n"
+            for l in lines.split("\n"):
+                code_block += "\n    " + l
+            lines = code_block + "\n\n"
+
+        for c, l in enumerate(lines.split("\n")):
+            content.append(l, fname, c)
+
+        buf  = self.state.memo.title_styles, self.state.memo.section_level, self.state.memo.reporter
+        self.state.memo.title_styles  = []
+        self.state.memo.section_level = 0
+        self.state.memo.reporter      = AutodocReporter(content, self.state.memo.reporter)
+        try:
+            self.state.nested_parse(content, 0, node, match_titles=1)
+        finally:
+            self.state.memo.title_styles, self.state.memo.section_level, self.state.memo.reporter = buf
+        return node.children
-- 
2.21.0