The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by
this change:
"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]
sizeof(flexible-array-member) triggers a warning because flexible array
members have incomplete type[1]. There are some instances of code in
which the sizeof operator is being incorrectly/erroneously applied to
zero-length arrays and the result is zero. Such instances may be hiding
some bugs. So, this work (flexible-array member conversions) will also
help to get completely rid of those sorts of issues.
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/20200507185347.GA14499@embeddedor
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
When calling debugfs functions, there is no need to ever check the
return value. The function can work or not, but the code logic should
never do something different based on this.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
One of the more common cases of allocation size calculations is finding
the size of a structure that has a zero-sized array at the end, along
with memory for some number of elements for that array. For example:
struct touchpad_protocol {
...
struct tp_finger fingers[0];
};
Make use of the struct_size() helper instead of an open-coded version
in order to avoid any potential type mistakes.
So, replace the following form:
sizeof(*tp) + tp->number_of_fingers * sizeof(tp->fingers[0]);
with:
struct_size(tp, fingers, tp->number_of_fingers)
This code was detected with the help of Coccinelle.
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
This fixes a typo in the keyboard_protocol description.
coodinate -> coordinate.
Signed-off-by: Nikolas Nyby <nikolas@gnu.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
This makes sure that we convert from on-wire to CPU endianness in
applespi_debug_update_dimensions() and also marks as "static" as it is not
needed to be visible outside of the driver.
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Ronald Tschalär <ronald@innovation.ch>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Fixes gcc '-Wunused-but-set-variable' warning:
drivers/input/keyboard/applespi.c: In function applespi_set_bl_level:
drivers/input/keyboard/applespi.c:902:6: warning: variable sts set but not used [-Wunused-but-set-variable]
Fixes: b426ac0452093d ("Input: add Apple SPI keyboard and trackpad driver")
Signed-off-by: Mao Wenan <maowenan@huawei.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
The keyboard and trackpad on recent MacBook's (since 8,1) and
MacBookPro's (13,* and 14,*) are attached to an SPI controller instead
of USB, as previously. The higher level protocol is not publicly
documented and hence has been reverse engineered. As a consequence there
are still a number of unknown fields and commands. However, the known
parts have been working well and received extensive testing and use.
In order for this driver to work, the proper SPI drivers need to be
loaded too; for MB8,1 these are spi_pxa2xx_platform and spi_pxa2xx_pci;
for all others they are spi_pxa2xx_platform and intel_lpss_pci.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=99891
Link: https://bugzilla.kernel.org/show_bug.cgi?id=108331
Signed-off-by: Ronald Tschalär <ronald@innovation.ch>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Gustavo A. R. Silva