linux-stable.git/include/linux/compiler-gcc4.h, branch v3.8.3

Merge tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

2012-12-19T15:55:08+00:00

Pull module update from Rusty Russell:
 "Nothing all that exciting; a new module-from-fd syscall for those who
  want to verify the source of the module (ChromeOS) and/or use standard
  IMA on it or other security hooks."

* tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
  MODSIGN: Fix kbuild output when using default extra_certificates
  MODSIGN: Avoid using .incbin in C source
  modules: don't hand 0 to vmalloc.
  module: Remove a extra null character at the top of module->strtab.
  ASN.1: Use the ASN1_LONG_TAG and ASN1_INDEFINITE_LENGTH constants
  ASN.1: Define indefinite length marker constant
  moduleparam: use __UNIQUE_ID()
  __UNIQUE_ID()
  MODSIGN: Add modules_sign make target
  powerpc: add finit_module syscall.
  ima: support new kernel module syscall
  add finit_module syscall to asm-generic
  ARM: add finit_module syscall to ARM
  security: introduce kernel_module_from_file hook
  module: add flags arg to sys_finit_module()
  module: add syscall to load module from fd

__UNIQUE_ID()

2012-12-14T02:35:30+00:00

Jan Beulich points out __COUNTER__ (gcc 4.3 and above), so let's use
that to create unique ids.  This is better than __LINE__ which we use
today, so provide a wrapper.

Stanislaw Gruszka  reported that some module parameters
start with a digit, so we need to prepend when we for the unique id.

Signed-off-by: Rusty Russell 
Acked-by: Jan Beulich

byteorder: allow arch to opt to use GCC intrinsics for byteswapping

2012-12-06T01:22:31+00:00

Since GCC 4.4, there have been __builtin_bswap32() and __builtin_bswap16()
intrinsics. A __builtin_bswap16() came a little later (4.6 for PowerPC,
48 for other platforms).

By using these instead of the inline assembler that most architectures
have in their __arch_swabXX() macros, we let the compiler see what's
actually happening. The resulting code should be at least as good, and
much *better* in the cases where it can be combined with a nearby load
or store, using a load-and-byteswap or store-and-byteswap instruction
(e.g. lwbrx/stwbrx on PowerPC, movbe on Atom).

When GCC is sufficiently recent *and* the architecture opts in to using
the intrinsics by setting CONFIG_ARCH_USE_BUILTIN_BSWAP, they will be
used in preference to the __arch_swabXX() macros. An architecture which
does not set ARCH_USE_BUILTIN_BSWAP will continue to use its own
hand-crafted macros.

Signed-off-by: David Woodhouse 
Acked-by: H. Peter Anvin

Merge branch 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild

2012-10-12T01:27:27+00:00

Pull kbuild changes from Michal Marek:
 "The main part of kbuild for v3.7 contains:
   - Fix for scripts/Makefile.modpost to not choke on a '.ko' substring
     in the build directory path
   - Two warning fixes (modpost and main Makefile)
   - __compiletime_error works also with gcc 4.3
   - make tar{gz,bz2,xz}-pkg uses default compression settings instead
     of saving as many bytes as possible (this should actually be in the
     misc branch, I don't know why I applied it here)."

* 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild:
  compiler-gcc4.h: correct verion check for __compiletime_error
  modpost: Permit .GCC.command.line sections
  Kbuild: use normal compression settings for tar*-pkg
  scripts/Makefile.modpost: error in finding modules from .mod files.
  kbuild: Remove useless warning while appending KCFLAGS

compiler-gcc4.h: correct verion check for __compiletime_error

2012-10-11T20:51:41+00:00

__attribute__((error(msg))) was introduced in gcc 4.3 (not 4.4) and as I
was unable to find any gcc bugs pertaining to it, I'm presuming that it
has functioned as advertised since 4.3.0.

Signed-off-by: Daniel Santos 
Signed-off-by: Andrew Morton 
Tested-by: David Rientjes 
Signed-off-by: Michal Marek

compiler.h: add __visible

2012-09-17T22:00:38+00:00

gcc 4.6+ has support for a externally_visible attribute that prevents the
optimizer from optimizing unused symbols away.  Add a __visible macro to
use it with that compiler version or later.

This is used (at least) by the "Link Time Optimization" patchset.

Signed-off-by: Andi Kleen 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kernel.h: add BUILD_BUG() macro

2012-01-11T00:30:42+00:00

We can place this in definitions that we expect the compiler to remove by
dead code elimination.  If this assertion fails, we get a nice error
message at build time.

The GCC function attribute error("message") was added in version 4.3, so
we define a new macro __linktime_error(message) to expand to this for
GCC-4.3 and later.  This will give us an error diagnostic from the
compiler on the line that fails.  For other compilers
__linktime_error(message) expands to nothing, and we have to be content
with a link time error, but at least we will still get a build error.

BUILD_BUG() expands to the undefined function __build_bug_failed() and
will fail at link time if the compiler ever emits code for it.  On GCC-4.3
and later, attribute((error())) is used so that the failure will be noted
at compile time instead.

Signed-off-by: David Daney 
Acked-by: David Rientjes 
Cc: DM 
Cc: Ralf Baechle 
Acked-by: David Howells 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

sparse: Undef __compiletime_{warning,error} if CHECKER is defined

2011-05-25T15:39:47+00:00

sparse can't parse warning and error attribute.  then they should be
hidden from sparse.

Signed-off-by: KOSAKI Motohiro 
Cc: Arjan van de Ven 
Cc: Dave Hansen 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

include/linux/compiler-gcc*.h: unify macro definitions

2011-03-23T00:44:10+00:00

Unify identical gcc3.x and gcc4.x macros.

Signed-off-by: Borislav Petkov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

compiler-gcc.h: gcc-4.5 needs noclone and noinline on __naked functions

2010-06-29T22:29:31+00:00

A __naked function is defined in C but with a body completely implemented
by asm(), including any prologue and epilogue.  These asm() bodies expect
standard calling conventions for parameter passing.  Older GCCs implement
that correctly, but 4.[56] currently do not, see GCC PR44290.  In the
Linux kernel this breaks ARM, causing most arch/arm/mm/copypage-*.c
modules to get miscompiled, resulting in kernel crashes during bootup.

Part of the kernel fix is to augment the __naked function attribute to
also imply noinline and noclone.  This patch implements that, and has been
verified to fix boot failures with gcc-4.5 compiled 2.6.34 and 2.6.35-rc1
kernels.  The patch is a no-op with older GCCs.

Signed-off-by: Mikael Pettersson 
Signed-off-by: Khem Raj 
Cc: Russell King 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds