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Rasmus Villemoes 6bab69c650 build_bug.h: add wrapper for _Static_assert
BUILD_BUG_ON() is a little annoying, since it cannot be used outside
function scope.  So one cannot put assertions about the sizeof() a
struct next to the struct definition, but has to hide that in some more
or less arbitrary function.

Since gcc 4.6 (which is now also the required minimum), there is support
for the C11 _Static_assert in all C modes, including gnu89.  So add a
simple wrapper for that.

_Static_assert() requires a message argument, which is usually quite
redundant (and I believe that bug got fixed at least in newer C++
standards), but we can easily work around that with a little macro
magic, making it optional.

For example, adding

  static_assert(sizeof(struct printf_spec) == 8);

in vsprintf.c and modifying that struct to violate it, one gets

./include/linux/build_bug.h:78:41: error: static assertion failed: "sizeof(struct printf_spec) == 8"
 #define __static_assert(expr, msg, ...) _Static_assert(expr, "" msg "")

godbolt.org suggests that _Static_assert() has been support by clang
since at least 3.0.0.

Link: http://lkml.kernel.org/r/20190208203015.29702-1-linux@rasmusvillemoes.dk
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Acked-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-07 18:31:59 -08:00
Documentation USB/PHY patches for 5.1-rc1 2019-03-06 16:48:27 -08:00
LICENSES This is a fairly typical cycle for documentation. There's some welcome 2018-10-24 18:01:11 +01:00
arch Driver core patches for 5.1-rc1 2019-03-06 14:52:48 -08:00
block for-linus-20190215 2019-02-15 09:12:28 -08:00
certs kbuild: remove redundant target cleaning on failure 2019-01-06 09:46:51 +09:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2019-03-05 09:09:55 -08:00
drivers USB/PHY patches for 5.1-rc1 2019-03-06 16:48:27 -08:00
fs Driver core patches for 5.1-rc1 2019-03-06 14:52:48 -08:00
include build_bug.h: add wrapper for _Static_assert 2019-03-07 18:31:59 -08:00
init Merge branch 'akpm' (patches from Andrew) 2019-03-06 10:31:36 -08:00
ipc y2038: syscalls: rename y2038 compat syscalls 2019-02-07 00:13:27 +01:00
kernel kernel/sys: annotate implicit fall through 2019-03-07 18:31:59 -08:00
lib Driver core patches for 5.1-rc1 2019-03-06 14:52:48 -08:00
mm mm,mremap: bail out earlier in mremap_to under map pressure 2019-03-05 21:07:21 -08:00
net Merge branch 'akpm' (patches from Andrew) 2019-03-06 10:31:36 -08:00
samples Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2019-03-05 08:26:13 -08:00
scripts scripts/spelling.txt: add more spellings to spelling.txt 2019-03-07 18:31:59 -08:00
security get rid of legacy 'get_ds()' function 2019-03-04 10:50:14 -08:00
sound Char/Misc driver patches for 5.1-rc1 2019-03-06 14:18:59 -08:00
tools Staging/IIO patches for 5.1-rc1 2019-03-06 16:29:27 -08:00
usr user/Makefile: Fix typo and capitalization in comment section 2018-12-11 00:18:03 +09:00
virt ACPI updates for 5.1-rc1 2019-03-06 13:33:11 -08:00
.clang-format clang-format: Update .clang-format with the latest for_each macro list 2019-01-19 19:26:06 +01:00
.cocciconfig
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore kbuild: Add support for DT binding schema checks 2018-12-13 09:41:32 -06:00
.mailmap .mailmap: Add Mathieu Othacehe 2019-02-21 11:41:19 +00:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS Char/Misc driver patches for 5.1-rc1 2019-03-06 14:18:59 -08:00
Kbuild Merge branch 'locking/atomics' into locking/core, to pick up WIP commits 2019-02-11 14:27:05 +01:00
Kconfig kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt 2018-08-02 08:06:55 +09:00
MAINTAINERS USB/PHY patches for 5.1-rc1 2019-03-06 16:48:27 -08:00
Makefile Driver core patches for 5.1-rc1 2019-03-06 14:52:48 -08:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.