[ Upstream commit 50d7bd38c3 ]
Kernel code has a regular need to describe groups of members within a
structure usually when they need to be copied or initialized separately
from the rest of the surrounding structure. The generally accepted design
pattern in C is to use a named sub-struct:
struct foo {
int one;
struct {
int two;
int three, four;
} thing;
int five;
};
This would allow for traditional references and sizing:
memcpy(&dst.thing, &src.thing, sizeof(dst.thing));
However, doing this would mean that referencing struct members enclosed
by such named structs would always require including the sub-struct name
in identifiers:
do_something(dst.thing.three);
This has tended to be quite inflexible, especially when such groupings
need to be added to established code which causes huge naming churn.
Three workarounds exist in the kernel for this problem, and each have
other negative properties.
To avoid the naming churn, there is a design pattern of adding macro
aliases for the named struct:
#define f_three thing.three
This ends up polluting the global namespace, and makes it difficult to
search for identifiers.
Another common work-around in kernel code avoids the pollution by avoiding
the named struct entirely, instead identifying the group's boundaries using
either a pair of empty anonymous structs of a pair of zero-element arrays:
struct foo {
int one;
struct { } start;
int two;
int three, four;
struct { } finish;
int five;
};
struct foo {
int one;
int start[0];
int two;
int three, four;
int finish[0];
int five;
};
This allows code to avoid needing to use a sub-struct named for member
references within the surrounding structure, but loses the benefits of
being able to actually use such a struct, making it rather fragile. Using
these requires open-coded calculation of sizes and offsets. The efforts
made to avoid common mistakes include lots of comments, or adding various
BUILD_BUG_ON()s. Such code is left with no way for the compiler to reason
about the boundaries (e.g. the "start" object looks like it's 0 bytes
in length), making bounds checking depend on open-coded calculations:
if (length > offsetof(struct foo, finish) -
offsetof(struct foo, start))
return -EINVAL;
memcpy(&dst.start, &src.start, offsetof(struct foo, finish) -
offsetof(struct foo, start));
However, the vast majority of places in the kernel that operate on
groups of members do so without any identification of the grouping,
relying either on comments or implicit knowledge of the struct contents,
which is even harder for the compiler to reason about, and results in
even more fragile manual sizing, usually depending on member locations
outside of the region (e.g. to copy "two" and "three", use the start of
"four" to find the size):
BUILD_BUG_ON((offsetof(struct foo, four) <
offsetof(struct foo, two)) ||
(offsetof(struct foo, four) <
offsetof(struct foo, three));
if (length > offsetof(struct foo, four) -
offsetof(struct foo, two))
return -EINVAL;
memcpy(&dst.two, &src.two, length);
In order to have a regular programmatic way to describe a struct
region that can be used for references and sizing, can be examined for
bounds checking, avoids forcing the use of intermediate identifiers,
and avoids polluting the global namespace, introduce the struct_group()
macro. This macro wraps the member declarations to create an anonymous
union of an anonymous struct (no intermediate name) and a named struct
(for references and sizing):
struct foo {
int one;
struct_group(thing,
int two;
int three, four;
);
int five;
};
if (length > sizeof(src.thing))
return -EINVAL;
memcpy(&dst.thing, &src.thing, length);
do_something(dst.three);
There are some rare cases where the resulting struct_group() needs
attributes added, so struct_group_attr() is also introduced to allow
for specifying struct attributes (e.g. __align(x) or __packed).
Additionally, there are places where such declarations would like to
have the struct be tagged, so struct_group_tagged() is added.
Given there is a need for a handful of UAPI uses too, the underlying
__struct_group() macro has been defined in UAPI so it can be used there
too.
To avoid confusing scripts/kernel-doc, hide the macro from its struct
parsing.
Co-developed-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Keith Packard <keithp@keithp.com>
Acked-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/lkml/20210728023217.GC35706@embeddedor
Enhanced-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Link: https://lore.kernel.org/lkml/41183a98-bdb9-4ad6-7eab-5a7292a6df84@rasmusvillemoes.dk
Enhanced-by: Dan Williams <dan.j.williams@intel.com>
Link: https://lore.kernel.org/lkml/1d9a2e6df2a9a35b2cdd50a9a68cac5991e7e5f0.camel@intel.com
Enhanced-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://lore.kernel.org/lkml/YQKa76A6XuFqgM03@phenom.ffwll.local
Acked-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Stable-dep-of: 58e0be1ef6 ("net: use struct_group to copy ip/ipv6 header addresses")
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 7d2c6b1edf ]
Changeset 6b80975c63 ("scripts: kernel-doc: fix typedef parsing")
added support for things like:
typedef unsigned long foo();
However, it caused a regression on this prototype:
typedef bool v4l2_check_dv_timings_fnc(const struct v4l2_dv_timings *t, void *handle);
This is only noticed after adding a patch that checks if the
kernel-doc identifier matches the typedef:
./scripts/kernel-doc -none $(git grep '^.. kernel-doc::' Documentation/ |cut -d ' ' -f 3|sort|uniq) 2>&1|grep expecting
include/media/v4l2-dv-timings.h:38: warning: expecting prototype for typedef v4l2_check_dv_timings_fnc. Prototype was for typedef nc instead
The problem is that, with the new parsing logic, it is not
checking for complete words at the type part.
Fix it by adding a \b at the end of each type word at the
regex.
fixes: 6b80975c63 ("scripts: kernel-doc: fix typedef parsing")
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/218ff56dcb8e73755005d3fb64586eb1841a276b.1606896997.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Sphinx C domain code after 3.2.1 will start complaning if :c:struct
would be used for an union type:
.../Documentation/gpu/drm-kms-helpers:352: ../drivers/video/hdmi.c:851: WARNING: C 'identifier' cross-reference uses wrong tag: reference name is 'union hdmi_infoframe' but found name is 'struct hdmi_infoframe'. Full reference name is 'union hdmi_infoframe'. Full found name is 'struct hdmi_infoframe'.
So, let's address this issue too in advance, in order to
avoid future issues.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/6e4ec3eec914df62389a299797a3880ae4490f35.1603791716.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
The include/linux/genalloc.h file defined this typedef:
typedef unsigned long (*genpool_algo_t)(unsigned long *map,unsigned long size,unsigned long start,unsigned int nr,void *data, struct gen_pool *pool, unsigned long start_addr);
Because it has a type composite of two words (unsigned long),
the parser gets the typedef name wrong:
.. c:macro:: long
**Typedef**: Allocation callback function type definition
Fix the regex in order to accept composite types when
defining a typedef for a function pointer.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/328e8018041cc44f7a1684e57f8d111230761c4f.1603792384.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
There are a few namespace clashes by using c:macro everywhere:
basically, when using it, we can't have something like:
.. c:struct:: pwm_capture
.. c:macro:: pwm_capture
So, we need to use, instead:
.. c:function:: int pwm_capture (struct pwm_device * pwm, struct pwm_capture * result, unsigned long timeout)
for the function declaration.
The kernel-doc change was proposed by Jakob Lykke Andersen here:
6fd2076ec0
Although I did a different implementation.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Address several issues related to pointing to the wrong line
number:
1) ensure that line numbers will always be initialized
When section is the default (Description), the line number
is not initializing, producing this:
$ ./scripts/kernel-doc --enable-lineno ./drivers/media/v4l2-core/v4l2-mem2mem.c|less
**Description**
#define LINENO 0
In case of streamoff or release called on any context,
1] If the context is currently running, then abort job will be called
2] If the context is queued, then the context will be removed from
the job_queue
Which is not right. Ensure that the line number will always
be there. After applied, the result now points to the right location:
**Description**
#define LINENO 410
In case of streamoff or release called on any context,
1] If the context is currently running, then abort job will be called
2] If the context is queued, then the context will be removed from
the job_queue
2) The line numbers for function prototypes are always + 1,
because it is taken at the line after handling the prototype.
Change the logic to point to the next line after the /** */
block;
3) The "DOC:" line number should point to the same line as this
markup is found, and not to the next one.
Probably part of the issues were due to a but that was causing
the line number offset to be incremented by one, if --export
were used.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
When kernel-doc is called via kerneldoc.py, there's no need to
auto-detect the Sphinx version, as the Sphinx module already
knows it. So, add an optional parameter to allow changing the
Sphinx dialect.
As kernel-doc can also be manually called, keep the auto-detection
logic if the parameter was not specified. On such case, emit
a warning if sphinx-build can't be found at PATH.
I ended using a suggestion from Joe for using a more readable
regex, instead of using a complex one with a hidden group like:
m/^(\d+)\.(\d+)(?:\.?(\d+)?)/
in order to get the optional <patch> argument.
Thanks-to: Joe Perches <joe@perches.com>
Suggested-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
While kernel-doc needs to parse parameters in order to
identify its name, it shouldn't be touching the type,
as parsing it is very difficult, and errors happen.
One current error is when parsing this parameter:
const u32 (*tab)[256]
Found at ./lib/crc32.c, on this function:
u32 __pure crc32_be_generic (u32 crc, unsigned char const *p, size_t len, const u32 (*tab)[256], u32 polynomial);
The current logic mangles it, producing this output:
const u32 ( *tab
That's something that it is not recognizeable.
So, instead, let's push the argument as-is, and use it
when printing the function prototype and when describing
each argument.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Some typedef expressions are output as normal functions.
As we need to be clearer about the type with Sphinx 3.x,
detect such cases.
While here, fix a wrongly-indented block.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Right now, the build system doesn't use -nofunction, as
it is pretty much useless, because it doesn't consider
the other output modes (extern, internal), working only
with all.
Also, it is limited to exclude functions.
Re-implement it in order to allow excluding any symbols from
the document output, no matter what mode is used.
The parameter was also renamed to "-nosymbol", as it express
better its meaning.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
There's currently a bug with the way kernel-doc script
counts line numbers that can be seen with:
$ ./scripts/kernel-doc -rst -enable-lineno include/linux/math64.h >all && ./scripts/kernel-doc -rst -internal -enable-lineno include/linux/math64.h >int && diff -U0 int all
--- int 2020-09-28 12:58:08.927486808 +0200
+++ all 2020-09-28 12:58:08.905486845 +0200
@@ -1 +1 @@
-#define LINENO 27
+#define LINENO 26
@@ -3 +3 @@
-#define LINENO 16
+#define LINENO 15
@@ -9 +9 @@
-#define LINENO 17
+#define LINENO 16
...
This is happening with perl version 5.30.3, but I'm not
so sure if this is a perl bug, or if this is due to something
else.
In any case, fixing it is easy. Basically, when "-internal"
parameter is used, the process_export_file() function opens the
handle "IN". This makes the line number to be incremented, as the
handler for the main open is also "IN".
Fix the problem by using a different handler for the
main open().
While here, add a missing close for it.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Unfortunately, Sphinx 3.x parser for c functions is too pedantic:
https://github.com/sphinx-doc/sphinx/issues/8241
While it could be relaxed with some configurations, there are
several corner cases that it would make it hard to maintain,
and will require teaching conf.py about several macros.
So, let's instead use the :c:macro notation. This will
produce an output that it is not as nice as currently, but it
should still be acceptable, and will provide cross-references,
removing thousands of warnings when building with newer
versions of Sphinx.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
With Sphinx 3.x, the ".. c:type:" tag was changed to accept either:
.. c:type:: typedef-like declaration
.. c:type:: name
Using it for other types (including functions) don't work anymore.
So, there are newer tags for macro, enum, struct, union, and others,
which doesn't exist on older versions.
Add a check for the Sphinx version and change the produced tags
accordingly.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
The PHY kernel-doc markup has gained support for documenting
a typedef enum.
However, right now the parser was not prepared for it.
So, add support for parsing it.
Fixes: 4069a572d4 ("net: phy: Document core PHY structures")
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Subroutine dump_struct uses type attributes to check if the struct
syntax is valid. Then, it removes all attributes before using it for
output. `____cacheline_aligned` is an attribute that is
not included in both steps. Add it, since it is used by kernel structs.
Based on previous patch to add ____cacheline_aligned_in_smp.
Motivated by patches to reorder this attribute to before the
variable name. Whilst we could do that in all cases, that would
be a massive change and it is more common in the kernel to place
this particular attribute after the variable name. A quick grep
suggests approximately 400 instances of which 341 have this
attribute just before a semicolon and hence after the variable name.
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20200910185415.653139-1-jic23@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
The kbuild bot recently added the W=1 option, which triggered
documentation cleanups to squelch hundreds of kernel-doc warnings.
To make sure new kernel contributions don't add regressions to
kernel-doc descriptors, this patch suggests an option to treat
warnings as errors in CI/automated tests.
A -Werror command-line option is added to the kernel-doc script. When
this option is set, the script will return the number of warnings
found. The caller can then treat this positive return value as an
error and stop the build.
Using this command line option is however not straightforward when the
kernel-doc script is called from other scripts. To align with typical
kernel compilation or documentation generation, the Werror option is
also set by checking the KCFLAGS environment variable, or if
KDOC_WERROR is defined, as in the following examples:
KCFLAGS="-Wall -Werror" make W=1 sound/
KCFLAGS="-Wall -Werror" make W=1 drivers/soundwire/
KDOC_WERROR=1 make htmldocs
Note that in the last example the documentation build does not stop,
only an additional log is provided.
Credits to Randy Dunlap for suggesting the use of environment variables.
Suggested-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20200728162040.92467-1-pierre-louis.bossart@linux.intel.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
The __ETHTOOL_DECLARE_LINK_MODE_MASK macro is a variant of
DECLARE_BITMAP(), used by phylink.h. As we have already a
parser for DECLARE_BITMAP(), let's add one for this macro,
in order to avoid such warnings:
./include/linux/phylink.h:54: warning: Function parameter or member '__ETHTOOL_DECLARE_LINK_MODE_MASK(advertising' not described in 'phylink_link_state'
./include/linux/phylink.h:54: warning: Function parameter or member '__ETHTOOL_DECLARE_LINK_MODE_MASK(lp_advertising' not described in 'phylink_link_state'
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/d1d1dea67a28117c0b0c33271b139c4455fef287.1592895969.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Rationale:
Reduces attack surface on kernel devs opening the links for MITM
as HTTPS traffic is much harder to manipulate.
Deterministic algorithm:
For each file:
For each line:
If doesn't contain `\bxmlns\b`:
For each link, `\bhttp://[^# \t\r\n]*(?:\w|/)`:
If both the HTTP and HTTPS versions
return 200 OK and serve the same content:
Replace HTTP with HTTPS.
Signed-off-by: Alexander A. Klimov <grandmaster@al2klimov.de>
Link: https://lore.kernel.org/r/20200526060544.25127-1-grandmaster@al2klimov.de
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Sphinx is very pedantic with respect to blank lines. Sometimes,
in order to make it to properly handle something, we need to
add a blank line. However, currently, any blank line inside a
kernel-doc comment like:
/*
* @foo: bar
*
* foobar
*
* some description
will be considered as if "foobar" was part of the description.
This patch changes kernel-doc behavior. After it, foobar will
be considered as part of the parameter text. The description
will only be considered as such if it starts with:
zero spaces after asterisk:
*foo
one space after asterisk:
* foo
or have a explicit Description section:
* Description:
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/c07d2862792d75a2691d69c9eceb7b89a0164cc0.1586881715.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
On a few places, it sometimes need to indicate a negation of a
parameter, like:
!@fshared
This pattern happens, for example, at:
kernel/futex.c
and it is perfectly valid. However, kernel-doc currently
transforms it into:
!**fshared**
This won't do what it would be expected.
Fortunately, fixing the script is a simple matter of storing
the "!" before "@" and adding it after the bold markup, like:
**!fshared**
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/0314b47f8c3e1f9db00d5375a73dc3cddd8a21f2.1586881715.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
The pattern @foo->bar() is valid, as it can be used by a
function pointer inside a struct passed as a parameter.
Right now, it causes a warning:
./drivers/firewire/core-transaction.c:606: WARNING: Inline strong start-string without end-string.
In this specific case, the kernel-doc markup is:
/**
* fw_core_remove_address_handler() - unregister an address handler
* @handler: callback
*
* To be called in process context.
*
* When fw_core_remove_address_handler() returns, @handler->callback() is
* guaranteed to not run on any CPU anymore.
*/
With seems valid on my eyes. So, instead of trying to hack
the kernel-doc markup, let's teach it about how to handle
such things. This should likely remove lots of other similar
warnings as well.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/48b46426d7bf6ff7529f20e5718fbf4e9758e62c.1586881715.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
