linux-toradex.git/include/linux/compiler.h, branch v2.6.38.5

rcu: define __rcu address space modifier for sparse

2010-08-20T00:17:59+00:00

This commit provides definitions for the __rcu annotation defined earlier.
This annotation permits sparse to check for correct use of RCU-protected
pointers.  If a pointer that is annotated with __rcu is accessed
directly (as opposed to via rcu_dereference(), rcu_assign_pointer(),
or one of their variants), sparse can be made to complain.  To enable
such complaints, use the new default-disabled CONFIG_SPARSE_RCU_POINTER
kernel configuration option.  Please note that these sparse complaints are
intended to be a debugging aid, -not- a code-style-enforcement mechanism.

There are special rcu_dereference_protected() and rcu_access_pointer()
accessors for use when RCU read-side protection is not required, for
example, when no other CPU has access to the data structure in question
or while the current CPU hold the update-side lock.

This patch also updates a number of docbook comments that were showing
their age.

Signed-off-by: Arnd Bergmann 
Signed-off-by: Paul E. McKenney 
Cc: Christopher Li 
Reviewed-by: Josh Triplett

rcu: add __rcu API for later sparse checking

2010-06-14T23:37:26+00:00

This commit defines an __rcu API, but provides only vacuous definitions
for it.  This breaks dependencies among most of the subsequent patches,
allowing them to reach mainline asynchronously via whatever trees are
appropriate.

Signed-off-by: Arnd Bergmann 
Signed-off-by: Paul E. McKenney 
Cc: Christopher Li 
Cc: Josh Triplett

Merge branch 'master' into percpu

2010-01-05T00:17:33+00:00

Conflicts:
	arch/powerpc/platforms/pseries/hvCall.S
	include/linux/percpu.h

Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

2009-12-05T23:32:03+00:00

* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  include/linux/compiler-gcc4.h: Fix build bug - gcc-4.0.2 doesn't understand __builtin_object_size
  x86/alternatives: No need for alternatives-asm.h to re-invent stuff already in asm.h
  x86/alternatives: Check replacementlen <= instrlen at build time
  x86, 64-bit: Set data segments to null after switching to 64-bit mode
  x86: Clean up the loadsegment() macro
  x86: Optimize loadsegment()
  x86: Add missing might_fault() checks to copy_{to,from}_user()
  x86-64: __copy_from_user_inatomic() adjustments
  x86: Remove unused thread_return label from switch_to()
  x86, 64-bit: Fix bstep_iret jump
  x86: Don't use the strict copy checks when branch profiling is in use
  x86, 64-bit: Move K8 B step iret fixup to fault entry asm
  x86: Generate cmpxchg build failures
  x86: Add a Kconfig option to turn the copy_from_user warnings into errors
  x86: Turn the copy_from_user check into an (optional) compile time warning
  x86: Use __builtin_memset and __builtin_memcpy for memset/memcpy
  x86: Use __builtin_object_size() to validate the buffer size for copy_from_user()

Merge branch 'tracing-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

2009-12-05T17:53:36+00:00

* 'tracing-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (40 commits)
  tracing: Separate raw syscall from syscall tracer
  ring-buffer-benchmark: Add parameters to set produce/consumer priorities
  tracing, function tracer: Clean up strstrip() usage
  ring-buffer benchmark: Run producer/consumer threads at nice +19
  tracing: Remove the stale include/trace/power.h
  tracing: Only print objcopy version warning once from recordmcount
  tracing: Prevent build warning: 'ftrace_graph_buf' defined but not used
  ring-buffer: Move access to commit_page up into function used
  tracing: do not disable interrupts for trace_clock_local
  ring-buffer: Add multiple iterations between benchmark timestamps
  kprobes: Sanitize struct kretprobe_instance allocations
  tracing: Fix to use __always_unused attribute
  compiler: Introduce __always_unused
  tracing: Exit with error if a weak function is used in recordmcount.pl
  tracing: Move conditional into update_funcs() in recordmcount.pl
  tracing: Add regex for weak functions in recordmcount.pl
  tracing: Move mcount section search to front of loop in recordmcount.pl
  tracing: Fix objcopy revision check in recordmcount.pl
  tracing: Check absolute path of input file in recordmcount.pl
  tracing: Correct the check for number of arguments in recordmcount.pl
  ...

Add support for GCC-4.5's __builtin_unreachable() to compiler.h (v2)

2009-12-05T17:10:12+00:00

Starting with version 4.5, GCC has a new built-in function
__builtin_unreachable() that can be used in places like the kernel's
BUG() where inline assembly is used to transfer control flow.  This
eliminated the need for an endless loop in these places.

The patch adds a new macro 'unreachable()' that will expand to either
__builtin_unreachable() or an endless loop depending on the compiler
version.

Change from v1: Simplify unreachable() for non-GCC 4.5 case.

Signed-off-by: David Daney 
Acked-by: Ralf Baechle 
Signed-off-by: Linus Torvalds

compiler: Introduce __always_unused

2009-11-02T14:47:54+00:00

I wrote some code which is used as compile-time checker, and the
code should be elided after compile.

So I need to annotate the code as "always unused", compared to
"maybe unused".

Signed-off-by: Li Zefan 
Cc: Steven Rostedt 
Cc: Frederic Weisbecker 
Cc: Linus Torvalds 
LKML-Reference: <4AEE2CEC.8040206@cn.fujitsu.com>
Signed-off-by: Ingo Molnar

percpu: add __percpu for sparse.

2009-10-29T13:34:15+00:00

We have to make __kernel "__attribute__((address_space(0)))" so we can
cast to it.

tj: * put_cpu_var() update.

    * Annotations added to dynamic allocator interface.

Signed-off-by: Rusty Russell 
Cc: Al Viro 
Signed-off-by: Tejun Heo

x86: Add a Kconfig option to turn the copy_from_user warnings into errors

2009-10-02T17:01:42+00:00

For automated testing it is useful to have the option to turn
the warnings on copy_from_user() etc checks into errors:

 In function ‘copy_from_user’,
     inlined from ‘fd_copyin’ at drivers/block/floppy.c:3080,
     inlined from ‘fd_ioctl’ at drivers/block/floppy.c:3503:
   linux/arch/x86/include/asm/uaccess_32.h:213:
  error: call to ‘copy_from_user_overflow’ declared with attribute error:
  copy_from_user buffer size is not provably correct

Signed-off-by: Arjan van de Ven 
Cc: Linus Torvalds 
Cc: Andrew Morton 
LKML-Reference: <20091002075050.4e9f7641@infradead.org>
Signed-off-by: Ingo Molnar

x86: Turn the copy_from_user check into an (optional) compile time warning

2009-10-01T09:31:04+00:00

A previous patch added the buffer size check to copy_from_user().

One of the things learned from analyzing the result of the previous
patch is that in general, gcc is really good at proving that the
code contains sufficient security checks to not need to do a
runtime check. But that for those cases where gcc could not prove
this, there was a relatively high percentage of real security
issues.

This patch turns the case of "gcc cannot prove" into a compile time
warning, as long as a sufficiently new gcc is in use that supports
this. The objective is that these warnings will trigger developers
checking new cases out before a security hole enters a linux kernel
release.

Signed-off-by: Arjan van de Ven 
Cc: Linus Torvalds 
Cc: "David S. Miller" 
Cc: James Morris 
Cc: Jan Beulich 
LKML-Reference: <20090930130523.348ae6c4@infradead.org>
Signed-off-by: Ingo Molnar