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  1. 11 Feb, 2018 1 commit
  3. 07 Feb, 2018 5 commits
  5. 28 Jan, 2018 1 commit
  7. 21 Jan, 2018 1 commit
  9. 14 Jan, 2018 1 commit
  11. 07 Jan, 2018 1 commit
  13. 31 Dec, 2017 1 commit
  15. 30 Dec, 2017 1 commit
    • Linus Torvalds's avatar
      kbuild: add '-fno-stack-check' to kernel build options · 3ce120b1
      Linus Torvalds authored 
      
It appears that hardened gentoo enables "-fstack-check" by default for
gcc.

That doesn't work _at_all_ for the kernel, because the kernel stack
doesn't act like a user stack at all: it's much smaller, and it doesn't
auto-expand on use.  So the extra "probe one page below the stack" code
generated by -fstack-check just breaks the kernel in horrible ways,
causing infinite double faults etc.

[ I have to say, that the particular code gcc generates looks very
  stupid even for user space where it works, but that's a separate
  issue.  ]
Reported-and-tested-by: default avatarAlexander Tsoy <alexander@tsoy.me>
Reported-and-tested-by: default avatarToralf Förster <toralf.foerster@gmx.de>
Cc: stable@kernel.org
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      3ce120b1
  17. 24 Dec, 2017 1 commit
  19. 18 Dec, 2017 1 commit
  21. 16 Dec, 2017 1 commit
  23. 11 Dec, 2017 1 commit
  25. 06 Dec, 2017 1 commit
  27. 03 Dec, 2017 1 commit
  29. 27 Nov, 2017 1 commit
  31. 23 Nov, 2017 3 commits
  33. 18 Nov, 2017 3 commits
    • Masahiro Yamada's avatar
      kbuild: create built-in.o automatically if parent directory wants it · f7adc312
      Masahiro Yamada authored 
      "obj-y += foo/" syntax requires Kbuild to visit the "foo" subdirectory
and link built-in.o from that directory.  This means foo/Makefile is
responsible for creating built-in.o even if there is no object to
link (in this case, built-in.o is an empty archive).

We have had several fixups like commit 4b024242

 ("kbuild: Fix
linking error built-in.o no such file or directory"), then ended up
with a complex condition as follows:

  ifneq ($(strip $(obj-y) $(obj-m) $(obj-) $(subdir-m) $(lib-target)),)
  builtin-target := $(obj)/built-in.o
  endif

We still have more cases not covered by the above, so we need to add
  obj- := dummy.o
in several places just for creating empty built-in.o.

A key point is, the parent Makefile knows whether built-in.o is needed
or not.  If a subdirectory needs to create built-in.o, its parent can
tell the fact when descending.

If non-empty $(need-builtin) flag is passed from the parent, built-in.o
should be created.  $(obj-y) should be still checked to support the
single target "%/".  All of ugly tricks will go away.
Signed-off-by: default avatarMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: default avatarSam Ravnborg <sam@ravnborg.org>
      f7adc312
    • Bjørn Forsman's avatar
      kbuild: /bin/pwd -> pwd · 16f8259c
      Bjørn Forsman authored 
      Most places use pwd and rely on $PATH lookup. Moving the remaining
absolute path /bin/pwd users over for consistency.

Also, a reason for doing /bin/pwd -> pwd instead of the other way around
is because I believe build systems should make little assumptions on
host filesystem layout. Case in point, we do this kind of patching
already in NixOS.

Ref. commit 028568d8


("kbuild: revert $(realpath ...) to $(shell cd ... && /bin/pwd)").
Signed-off-by: default avatarBjørn Forsman <bjorn.forsman@gmail.com>
Signed-off-by: default avatarMasahiro Yamada <yamada.masahiro@socionext.com>
      16f8259c
    • Victor Chibotaru's avatar
      Makefile: support flag -fsanitizer-coverage=trace-cmp · d677a4d6
      Victor Chibotaru authored 
      The flag enables Clang instrumentation of comparison operations
(currently not supported by GCC).  This instrumentation is needed by the
new KCOV device to collect comparison operands.

Link: http://lkml.kernel.org/r/20171011095459.70721-2-glider@google.com

Signed-off-by: default avatarVictor Chibotaru <tchibo@google.com>
Signed-off-by: default avatarAlexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Alexander Popov <alex.popov@linux.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Cc: <syzkaller@googlegroups.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      d677a4d6
  35. 16 Nov, 2017 2 commits
  37. 13 Nov, 2017 3 commits
    • Masahiro Yamada's avatar
      kbuild: do not call cc-option before KBUILD_CFLAGS initialization · 433dc2eb
      Masahiro Yamada authored 
      
Some $(call cc-option,...) are invoked very early, even before
KBUILD_CFLAGS, etc. are initialized.

The returned string from $(call cc-option,...) depends on
KBUILD_CPPFLAGS, KBUILD_CFLAGS, and GCC_PLUGINS_CFLAGS.

Since they are exported, they are not empty when the top Makefile
is recursively invoked.

The recursion occurs in several places.  For example, the top
Makefile invokes itself for silentoldconfig.  "make tinyconfig",
"make rpm-pkg" are the cases, too.

In those cases, the second call of cc-option from the same line
runs a different shell command due to non-pristine KBUILD_CFLAGS.

To get the same result all the time, KBUILD_* and GCC_PLUGINS_CFLAGS
must be initialized before any call of cc-option.  This avoids
garbage data in the .cache.mk file.

Move all calls of cc-option below the config targets because target
compiler flags are unnecessary for Kconfig.
Signed-off-by: default avatarMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: default avatarDouglas Anderson <dianders@chromium.org>
      433dc2eb
    • Douglas Anderson's avatar
      kbuild: Cache a few more calls to the compiler · 4e562071
      Douglas Anderson authored 
      
These are a few stragglers that I left out of the original patch to
cache calls to the C compiler ("kbuild: Add a cache for generated
variables") because they bleed out into the main Makefile and thus
uglify things a little bit.  The idea is the same here, though.
Signed-off-by: default avatarDouglas Anderson <dianders@chromium.org>
Tested-by: default avatarIngo Molnar <mingo@kernel.org>
Tested-by: default avatarGuenter Roeck <linux@roeck-us.net>
Signed-off-by: default avatarMasahiro Yamada <yamada.masahiro@socionext.com>
      4e562071
    • Douglas Anderson's avatar
      kbuild: Add a cache for generated variables · 3298b690
      Douglas Anderson authored 
      
While timing a "no-op" build of the kernel (incrementally building the
kernel even though nothing changed) in the Chrome OS build system I
found that it was much slower than I expected.

Digging into things a bit, I found that quite a bit of the time was
spent invoking the C compiler even though we weren't actually building
anything.  Currently in the Chrome OS build system the C compiler is
called through a number of wrappers (one of which is written in
python!) and can take upwards of 100 ms to invoke even if we're not
doing anything difficult, so these invocations of the compiler were
taking a lot of time.  Worse the invocations couldn't seem to take
advantage of the multiple cores on my system.

Certainly it seems like we could make the compiler invocations in the
Chrome OS build system faster, but only to a point.  Inherently
invoking a program as big as a C compiler is a fairly heavy
operation.  Thus even if we can speed the compiler calls it made sense
to track down what was happening.

It turned out that all the compiler invocations were coming from
usages like this in the kernel's Makefile:

KBUILD_CFLAGS += $(call cc-option,-fno-delete-null-pointer-checks,)

Due to the way cc-option and similar statements work the above
contains an implicit call to the C compiler.  ...and due to the fact
that we're storing the result in KBUILD_CFLAGS, a simply expanded
variable, the call will happen every time the Makefile is parsed, even
if there are no users of KBUILD_CFLAGS.

Rather than redoing this computation every time, it makes a lot of
sense to cache the result of all of the Makefile's compiler calls just
like we do when we compile a ".c" file to a ".o" file.  Conceptually
this is quite a simple idea.  ...and since the calls to invoke the
compiler and similar tools are centrally located in the Kbuild.include
file this doesn't even need to be super invasive.

Implementing the cache in a simple-to-use and efficient way is not
quite as simple as it first sounds, though.  To get maximum speed we
really want the cache in a format that make can natively understand
and make doesn't really have an ability to load/parse files. ...but
make _can_ import other Makefiles, so the solution is to store the
cache in Makefile format.  This requires coming up with a valid/unique
Makefile variable name for each value to be cached, but that's
solvable with some cleverness.

After this change, we'll automatically create a ".cache.mk" file that
will contain our cached variables.  We'll load this on each invocation
of make and will avoid recomputing anything that's already in our
cache.  The cache is stored in a format that it shouldn't need any
invalidation since anything that might change should affect the "key"
and any old cached value won't be used.
Signed-off-by: default avatarDouglas Anderson <dianders@chromium.org>
Tested-by: default avatarIngo Molnar <mingo@kernel.org>
Tested-by: default avatarGuenter Roeck <linux@roeck-us.net>
Signed-off-by: default avatarMasahiro Yamada <yamada.masahiro@socionext.com>
      3298b690
  39. 12 Nov, 2017 1 commit
  41. 08 Nov, 2017 1 commit
  43. 05 Nov, 2017 1 commit
  45. 02 Nov, 2017 1 commit
    • Greg Kroah-Hartman's avatar
      License cleanup: add SPDX GPL-2.0 license identifier to files with no license · b2441318
      Greg Kroah-Hartman authored 
      Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier.  The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
 - file had no licensing information it it.
 - file was a */uapi/* one with no licensing information in it,
 - file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard...
      b2441318
  47. 29 Oct, 2017 1 commit
  49. 26 Oct, 2017 1 commit
  51. 24 Oct, 2017 1 commit
  53. 23 Oct, 2017 1 commit
  55. 16 Oct, 2017 1 commit
  57. 14 Oct, 2017 1 commit
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