linux-toradex.git/include/asm-generic, branch v2.6.38-rc5

tracing: Replace syscall_meta_data struct array with pointer array

2011-02-03T14:29:06+00:00

Currently the syscall_meta structures for the syscall tracepoints are
placed in the __syscall_metadata section, and at link time, the linker
makes one large array of all these syscall metadata structures. On boot
up, this array is read (much like the initcall sections) and the syscall
data is processed.

The problem is that there is no guarantee that gcc will place complex
structures nicely together in an array format. Two structures in the
same file may be placed awkwardly, because gcc has no clue that they
are suppose to be in an array.

A hack was used previous to force the alignment to 4, to pack the
structures together. But this caused alignment issues with other
architectures (sparc).

Instead of packing the structures into an array, the structures' addresses
are now put into the __syscall_metadata section. As pointers are always the
natural alignment, gcc should always pack them tightly together
(otherwise initcall, extable, etc would also fail).

By having the pointers to the structures in the section, we can still
iterate the trace_events without causing unnecessary alignment problems
with other architectures, or depending on the current behaviour of
gcc that will likely change in the future just to tick us kernel developers
off a little more.

The __syscall_metadata section is also moved into the .init.data section
as it is now only needed at boot up.

Suggested-by: David Miller 
Acked-by: David S. Miller 
Cc: Mathieu Desnoyers 
Signed-off-by: Steven Rostedt

tracepoints: Fix section alignment using pointer array

2011-02-03T14:28:46+00:00

Make the tracepoints more robust, making them solid enough to handle compiler
changes by not relying on anything based on compiler-specific behavior with
respect to structure alignment. Implement an approach proposed by David Miller:
use an array of const pointers to refer to the individual structures, and export
this pointer array through the linker script rather than the structures per se.
It will consume 32 extra bytes per tracepoint (24 for structure padding and 8
for the pointers), but are less likely to break due to compiler changes.

History:

commit 7e066fb8 tracepoints: add DECLARE_TRACE() and DEFINE_TRACE()
added the aligned(32) type and variable attribute to the tracepoint structures
to deal with gcc happily aligning statically defined structures on 32-byte
multiples.

One attempt was to use a 8-byte alignment for tracepoint structures by applying
both the variable and type attribute to tracepoint structures definitions and
declarations. It worked fine with gcc 4.5.1, but broke with gcc 4.4.4 and 4.4.5.

The reason is that the "aligned" attribute only specify the _minimum_ alignment
for a structure, leaving both the compiler and the linker free to align on
larger multiples. Because tracepoint.c expects the structures to be placed as an
array within each section, up-alignment cause NULL-pointer exceptions due to the
extra unexpected padding.

(this patch applies on top of -tip)

Signed-off-by: Mathieu Desnoyers 
Acked-by: David S. Miller 
LKML-Reference: <20110126222622.GA10794@Krystal>
CC: Frederic Weisbecker 
CC: Ingo Molnar 
CC: Thomas Gleixner 
CC: Andrew Morton 
CC: Peter Zijlstra 
CC: Rusty Russell 
Signed-off-by: Steven Rostedt

tracing: Replace trace_event struct array with pointer array

2011-02-03T02:37:13+00:00

Currently the trace_event structures are placed in the _ftrace_events
section, and at link time, the linker makes one large array of all
the trace_event structures. On boot up, this array is read (much like
the initcall sections) and the events are processed.

The problem is that there is no guarantee that gcc will place complex
structures nicely together in an array format. Two structures in the
same file may be placed awkwardly, because gcc has no clue that they
are suppose to be in an array.

A hack was used previous to force the alignment to 4, to pack the
structures together. But this caused alignment issues with other
architectures (sparc).

Instead of packing the structures into an array, the structures' addresses
are now put into the _ftrace_event section. As pointers are always the
natural alignment, gcc should always pack them tightly together
(otherwise initcall, extable, etc would also fail).

By having the pointers to the structures in the section, we can still
iterate the trace_events without causing unnecessary alignment problems
with other architectures, or depending on the current behaviour of
gcc that will likely change in the future just to tick us kernel developers
off a little more.

The _ftrace_event section is also moved into the .init.data section
as it is now only needed at boot up.

Suggested-by: David Miller 
Cc: Mathieu Desnoyers 
Acked-by: David S. Miller 
Signed-off-by: Steven Rostedt

module: show version information for built-in modules in sysfs

2011-01-24T04:02:51+00:00

Currently only drivers that are built as modules have their versions
shown in /sys/module//version, but this information might
also be useful for built-in drivers as well. This especially important
for drivers that do not define any parameters - such drivers, if
built-in, are completely invisible from userspace.

This patch changes MODULE_VERSION() macro so that in case when we are
compiling built-in module, version information is stored in a separate
section. Kernel then uses this data to create 'version' sysfs attribute
in the same fashion it creates attributes for module parameters.

Signed-off-by: Dmitry Torokhov 
Signed-off-by: Rusty Russell

fix non-x86 build failure in pmdp_get_and_clear

2011-01-16T23:05:44+00:00

pmdp_get_and_clear/pmdp_clear_flush/pmdp_splitting_flush were trapped as
BUG() and they were defined only to diminish the risk of build issues on
not-x86 archs and to be consistent with the generic pte methods previously
defined in include/asm-generic/pgtable.h.

But they are causing more trouble than they were supposed to solve, so
it's simpler not to define them when THP is off.

This is also correcting the export of pmdp_splitting_flush which is
currently unused (x86 isn't using the generic implementation in
mm/pgtable-generic.c and no other arch needs that [yet]).

Signed-off-by: Andrea Arcangeli 
Sam Ravnborg 
Cc: Stephen Rothwell 
Cc: "David S. Miller" 
Cc: Benjamin Herrenschmidt 
Cc: "Luck, Tony" 
Cc: James Bottomley 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

thp: mm: define MADV_NOHUGEPAGE

2011-01-14T01:32:47+00:00

Define MADV_NOHUGEPAGE.

Signed-off-by: Andrea Arcangeli 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

thp: add pmd mangling generic functions

2011-01-14T01:32:40+00:00

Some are needed to build but not actually used on archs not supporting
transparent hugepages.  Others like pmdp_clear_flush are used by x86 too.

Signed-off-by: Andrea Arcangeli 
Acked-by: Rik van Riel 
Acked-by: Mel Gorman 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

thp: special pmd_trans_* functions

2011-01-14T01:32:40+00:00

These returns 0 at compile time when the config option is disabled, to
allow gcc to eliminate the transparent hugepage function calls at compile
time without additional #ifdefs (only the export of those functions have
to be visible to gcc but they won't be required at link time and
huge_memory.o can be not built at all).

_PAGE_BIT_UNUSED1 is never used for pmd, only on pte.

Signed-off-by: Andrea Arcangeli 
Acked-by: Rik van Riel 
Acked-by: Mel Gorman 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

thp: mm: define MADV_HUGEPAGE

2011-01-14T01:32:38+00:00

Define MADV_HUGEPAGE.

Signed-off-by: Andrea Arcangeli 
Acked-by: Rik van Riel 
Acked-by: Arnd Bergmann 
Acked-by: Mel Gorman 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Revert "gpiolib: annotate gpio-intialization with __must_check"

2011-01-14T01:26:46+00:00

This reverts commit 0fdae42d361bbb431ca0ab0efed5126a94821177, which
wasn't really supposed to go in, and causes lots of annoying warnings.

Quoth Andrew:
  "Complete brainfart - I meant to drop that patch ages ago."

Quoth Greg:
  "Ick, yeah, that patch isn't ok to go in as-is, all of the callers
   need to be fixed up first, which is what I thought we had agreed on..."

Reported-by: Stephen Rothwell 
Acked-by: Andrew Morton 
Acked-by: Greg KH 
Signed-off-by: Linus Torvalds