Commit Graph

687 Commits

Author SHA1 Message Date
David S. Miller
86e4ca66e8 bug.h: Move ratelimit warn interfaces to ratelimit.h
As reported by Ingo Molnar, we still have configuration combinations
where use of the WARN_RATELIMIT interfaces break the build because
dependencies don't get met.

Instead of going down the long road of trying to make it so that
ratelimit.h can get included by kernel.h or asm-generic/bug.h,
just move the interface into ratelimit.h and make users have
to include that.

Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Randy Dunlap <randy.dunlap@oracle.com>
2011-05-26 15:00:31 -04:00
David S. Miller
6b36783546 bug.h: Fix build with CONFIG_PRINTK disabled.
Based upon an email by Joe Perches.

Reported-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Randy Dunlap <randy.dunlap@oracle.com>
2011-05-24 16:15:56 -04:00
Joe Perches
b3eec79b07 bug.h: Add WARN_RATELIMIT
Add a generic mechanism to ratelimit WARN(foo, fmt, ...) messages
using a hidden per call site static struct ratelimit_state.

Also add an __WARN_RATELIMIT variant to be able to use a specific
struct ratelimit_state.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2011-05-23 17:37:43 -04:00
Linus Torvalds
268bb0ce3e sanitize <linux/prefetch.h> usage
Commit e66eed651f ("list: remove prefetching from regular list
iterators") removed the include of prefetch.h from list.h, which
uncovered several cases that had apparently relied on that rather
obscure header file dependency.

So this fixes things up a bit, using

   grep -L linux/prefetch.h $(git grep -l '[^a-z_]prefetchw*(' -- '*.[ch]')
   grep -L 'prefetchw*(' $(git grep -l 'linux/prefetch.h' -- '*.[ch]')

to guide us in finding files that either need <linux/prefetch.h>
inclusion, or have it despite not needing it.

There are more of them around (mostly network drivers), but this gets
many core ones.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-20 12:50:29 -07:00
Linus Torvalds
df48d8716e Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (107 commits)
  perf stat: Add more cache-miss percentage printouts
  perf stat: Add -d -d and -d -d -d options to show more CPU events
  ftrace/kbuild: Add recordmcount files to force full build
  ftrace: Add self-tests for multiple function trace users
  ftrace: Modify ftrace_set_filter/notrace to take ops
  ftrace: Allow dynamically allocated function tracers
  ftrace: Implement separate user function filtering
  ftrace: Free hash with call_rcu_sched()
  ftrace: Have global_ops store the functions that are to be traced
  ftrace: Add ops parameter to ftrace_startup/shutdown functions
  ftrace: Add enabled_functions file
  ftrace: Use counters to enable functions to trace
  ftrace: Separate hash allocation and assignment
  ftrace: Create a global_ops to hold the filter and notrace hashes
  ftrace: Use hash instead for FTRACE_FL_FILTER
  ftrace: Replace FTRACE_FL_NOTRACE flag with a hash of ignored functions
  perf bench, x86: Add alternatives-asm.h wrapper
  x86, 64-bit: Fix copy_[to/from]_user() checks for the userspace address limit
  x86, mem: memset_64.S: Optimize memset by enhanced REP MOVSB/STOSB
  x86, mem: memmove_64.S: Optimize memmove by enhanced REP MOVSB/STOSB
  ...
2011-05-19 17:36:08 -07:00
Alessio Igor Bogani
f02e8a6596 module: Sort exported symbols
This patch places every exported symbol in its own section
(i.e. "___ksymtab+printk").  Thus the linker will use its SORT() directive
to sort and finally merge all symbol in the right and final section
(i.e. "__ksymtab").

The symbol prefixed archs use an underscore as prefix for symbols.
To avoid collision we use a different character to create the temporary
section names.

This work was supported by a hardware donation from the CE Linux Forum.

Signed-off-by: Alessio Igor Bogani <abogani@kernel.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (folded in '+' fixup)
Tested-by: Dirk Behme <dirk.behme@googlemail.com>
2011-05-19 16:55:27 +09:30
Ingo Molnar
32673822e4 Merge branch 'tip/perf/core' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into perf/core
Conflicts:
	include/linux/perf_event.h

Merge reason: pick up the latest jump-label enhancements, they are cooked ready.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-27 10:40:21 +02:00
Linus Torvalds
42933bac11 Merge branch 'for-linus2' of git://git.profusion.mobi/users/lucas/linux-2.6
* 'for-linus2' of git://git.profusion.mobi/users/lucas/linux-2.6:
  Fix common misspellings
2011-04-07 11:14:49 -07:00
Jason Baron
d430d3d7e6 jump label: Introduce static_branch() interface
Introduce:

static __always_inline bool static_branch(struct jump_label_key *key);

instead of the old JUMP_LABEL(key, label) macro.

In this way, jump labels become really easy to use:

Define:

        struct jump_label_key jump_key;

Can be used as:

        if (static_branch(&jump_key))
                do unlikely code

enable/disale via:

        jump_label_inc(&jump_key);
        jump_label_dec(&jump_key);

that's it!

For the jump labels disabled case, the static_branch() becomes an
atomic_read(), and jump_label_inc()/dec() are simply atomic_inc(),
atomic_dec() operations. We show testing results for this change below.

Thanks to H. Peter Anvin for suggesting the 'static_branch()' construct.

Since we now require a 'struct jump_label_key *key', we can store a pointer into
the jump table addresses. In this way, we can enable/disable jump labels, in
basically constant time. This change allows us to completely remove the previous
hashtable scheme. Thanks to Peter Zijlstra for this re-write.

Testing:

I ran a series of 'tbench 20' runs 5 times (with reboots) for 3
configurations, where tracepoints were disabled.

jump label configured in
avg: 815.6

jump label *not* configured in (using atomic reads)
avg: 800.1

jump label *not* configured in (regular reads)
avg: 803.4

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20110316212947.GA8792@redhat.com>
Signed-off-by: Jason Baron <jbaron@redhat.com>
Suggested-by: H. Peter Anvin <hpa@linux.intel.com>
Tested-by: David Daney <ddaney@caviumnetworks.com>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-04-04 12:48:08 -04:00
Lucas De Marchi
25985edced Fix common misspellings
Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
2011-03-31 11:26:23 -03:00
Steven Rostedt
ccd0d44fad WARN_ON_SMP(): Add comment to explain ({0;})
The define to use ({0;}) for the !CONFIG_SMP case of WARN_ON_SMP()
can be confusing. As the WARN_ON_SMP() needs to be a nop when
CONFIG_SMP is not set, including all its parameters must not be
evaluated, and that it must work as both a stand alone statement
and inside an if condition, we define it to a funky ({0;}).

A simple "0" will not work as it causes gcc to give the warning that
the statement has no effect.

As this strange definition has raised a few eyebrows from some
major kernel developers, it is wise to document why we create such
a work of art.

Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-03-28 10:10:42 -04:00
Linus Torvalds
94df491c4a Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  futex: Fix WARN_ON() test for UP
  WARN_ON_SMP(): Allow use in if() statements on UP
  x86, dumpstack: Use %pB format specifier for stack trace
  vsprintf: Introduce %pB format specifier
  lockdep: Remove unused 'factor' variable from lockdep_stats_show()
2011-03-25 17:52:22 -07:00
Steven Rostedt
2092e6be82 WARN_ON_SMP(): Allow use in if() statements on UP
Both WARN_ON() and WARN_ON_SMP() should be able to be used in
an if statement.

	if (WARN_ON_SMP(foo)) { ... }

Because WARN_ON_SMP() is defined as a do { } while (0) on UP,
it can not be used this way.

Convert it to the same form that WARN_ON() is, even when
CONFIG_SMP is off.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Darren Hart <dvhart@linux.intel.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <20110317192208.444147791@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-03-25 11:32:09 +01:00
Akinobu Mita
61f2e7b0f4 bitops: remove minix bitops from asm/bitops.h
minix bit operations are only used by minix filesystem and useless by
other modules.  Because byte order of inode and block bitmaps is different
on each architecture like below:

m68k:
	big-endian 16bit indexed bitmaps

h8300, microblaze, s390, sparc, m68knommu:
	big-endian 32 or 64bit indexed bitmaps

m32r, mips, sh, xtensa:
	big-endian 32 or 64bit indexed bitmaps for big-endian mode
	little-endian bitmaps for little-endian mode

Others:
	little-endian bitmaps

In order to move minix bit operations from asm/bitops.h to architecture
independent code in minix filesystem, this provides two config options.

CONFIG_MINIX_FS_BIG_ENDIAN_16BIT_INDEXED is only selected by m68k.
CONFIG_MINIX_FS_NATIVE_ENDIAN is selected by the architectures which use
native byte order bitmaps (h8300, microblaze, s390, sparc, m68knommu,
m32r, mips, sh, xtensa).  The architectures which always use little-endian
bitmaps do not select these options.

Finally, we can remove minix bit operations from asm/bitops.h for all
architectures.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Greg Ungerer <gerg@uclinux.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Roman Zippel <zippel@linux-m68k.org>
Cc: Andreas Schwab <schwab@linux-m68k.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Michal Simek <monstr@monstr.eu>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Hirokazu Takata <takata@linux-m32r.org>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Cc: Chris Zankel <chris@zankel.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-23 19:46:22 -07:00
Akinobu Mita
f312eff816 bitops: remove ext2 non-atomic bitops from asm/bitops.h
As the result of conversions, there are no users of ext2 non-atomic bit
operations except for ext2 filesystem itself.  Now we can put them into
architecture independent code in ext2 filesystem, and remove from
asm/bitops.h for all architectures.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-23 19:46:21 -07:00
Akinobu Mita
c56530055a asm-generic: use little-endian bitops
As a preparation for removing ext2 non-atomic bit operations from
asm/bitops.h.  This converts ext2 non-atomic bit operations to
little-endian bit operations.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-23 19:46:15 -07:00
Akinobu Mita
861b5ae7cd bitops: introduce little-endian bitops for most architectures
Introduce little-endian bit operations to the big-endian architectures
which do not have native little-endian bit operations and the
little-endian architectures.  (alpha, avr32, blackfin, cris, frv, h8300,
ia64, m32r, mips, mn10300, parisc, sh, sparc, tile, x86, xtensa)

These architectures can just include generic implementation
(asm-generic/bitops/le.h).

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Mikael Starvik <starvik@axis.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Matthew Wilcox <willy@debian.org>
Cc: Grant Grundler <grundler@parisc-linux.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Kazumoto Kojima <kkojima@rr.iij4u.or.jp>
Cc: Hirokazu Takata <takata@linux-m32r.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Chris Zankel <chris@zankel.net>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com>
Acked-by: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-23 19:46:15 -07:00
Akinobu Mita
a56560b3b2 asm-generic: change little-endian bitops to take any pointer types
This makes the little-endian bitops take any pointer types by changing the
prototypes and adding casts in the preprocessor macros.

That would seem to at least make all the filesystem code happier, and they
can continue to do just something like

  #define ext2_set_bit __test_and_set_bit_le

(or whatever the exact sequence ends up being).

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Mikael Starvik <starvik@axis.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Matthew Wilcox <willy@debian.org>
Cc: Grant Grundler <grundler@parisc-linux.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Kazumoto Kojima <kkojima@rr.iij4u.or.jp>
Cc: Hirokazu Takata <takata@linux-m32r.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Chris Zankel <chris@zankel.net>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-23 19:46:12 -07:00
Akinobu Mita
c4945b9ed4 asm-generic: rename generic little-endian bitops functions
As a preparation for providing little-endian bitops for all architectures,
This renames generic implementation of little-endian bitops.  (remove
"generic_" prefix and postfix "_le")

s/generic_find_next_le_bit/find_next_bit_le/
s/generic_find_next_zero_le_bit/find_next_zero_bit_le/
s/generic_find_first_zero_le_bit/find_first_zero_bit_le/
s/generic___test_and_set_le_bit/__test_and_set_bit_le/
s/generic___test_and_clear_le_bit/__test_and_clear_bit_le/
s/generic_test_le_bit/test_bit_le/
s/generic___set_le_bit/__set_bit_le/
s/generic___clear_le_bit/__clear_bit_le/
s/generic_test_and_set_le_bit/test_and_set_bit_le/
s/generic_test_and_clear_le_bit/test_and_clear_bit_le/

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Roman Zippel <zippel@linux-m68k.org>
Cc: Andreas Schwab <schwab@linux-m68k.org>
Cc: Greg Ungerer <gerg@uclinux.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-23 19:46:11 -07:00
Akinobu Mita
63ab595fb6 bitops: merge little and big endian definisions in asm-generic/bitops/le.h
This patch series introduces little-endian bit operations in asm/bitops.h
for all architectures and converts all ext2 non-atomic and minix bit
operations to use little-endian bit operations.  It enables us to remove
ext2 non-atomic and minix bit operations from asm/bitops.h.  The reason
they should be removed from asm/bitops.h is as follows:

For ext2 non-atomic bit operations, they are used for little-endian byte
order bitmap access by some filesystems and modules.  But using ext2_*()
functions on a module other than ext2 filesystem makes some feel strange.

For minix bit operations, they are only used by minix filesystem and are
useless by other modules.  Because byte order of inode and block bitmap is

This patch:

In order to make the forthcoming changes smaller, this merges macro
definisions in asm-generic/bitops/le.h for big-endian and little-endian as
much as possible.

This also removes unused BITOP_WORD macro.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-23 19:46:11 -07:00
FUJITA Tomonori
3e50594e8e add the common dma_addr_t typedef to include/linux/types.h
All architectures can use the common dma_addr_t typedef now. We can
remove the arch specific dma_addr_t.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Matt Turner <mattst88@gmail.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-22 17:44:09 -07:00
Andrew Morton
c7a1fcd8e6 include/asm-generic/unistd.h: fix syncfs syscall number
syncfs() is duplicating name_to_handle_at() due to a merging mistake.

Cc: Sage Weil <sage@newdream.net>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-22 17:43:58 -07:00
Sage Weil
b7ed78f565 introduce sys_syncfs to sync a single file system
It is frequently useful to sync a single file system, instead of all
mounted file systems via sync(2):

 - On machines with many mounts, it is not at all uncommon for some of
   them to hang (e.g. unresponsive NFS server).  sync(2) will get stuck on
   those and may never get to the one you do care about (e.g., /).
 - Some applications write lots of data to the file system and then
   want to make sure it is flushed to disk.  Calling fsync(2) on each
   file introduces unnecessary ordering constraints that result in a large
   amount of sub-optimal writeback/flush/commit behavior by the file
   system.

There are currently two ways (that I know of) to sync a single super_block:

 - BLKFLSBUF ioctl on the block device: That also invalidates the bdev
   mapping, which isn't usually desirable, and doesn't work for non-block
   file systems.
 - 'mount -o remount,rw' will call sync_filesystem as an artifact of the
   current implemention.  Relying on this little-known side effect for
   something like data safety sounds foolish.

Both of these approaches require root privileges, which some applications
do not have (nor should they need?) given that sync(2) is an unprivileged
operation.

This patch introduces a new system call syncfs(2) that takes an fd and
syncs only the file system it references.  Maybe someday we can

 $ sync /some/path

and not get

 sync: ignoring all arguments

The syscall is motivated by comments by Al and Christoph at the last LSF.
syncfs(2) seems like an appropriate name given statfs(2).

A similar ioctl was also proposed a while back, see
	http://marc.info/?l=linux-fsdevel&m=127970513829285&w=2

Signed-off-by: Sage Weil <sage@newdream.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-03-21 00:40:29 -04:00
Chris Metcalf
339dc50e59 asm-generic: support clock_adjtime() in <asm-generic/unistd.h>
A syscall was added without being added to asm-generic, which
makes tile (and presumably score and unicore32) break.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: Chen Liqin <liqin.chen@sunplusct.com>
Cc: Lennox Wu <lennox.wu@gmail.com>
2011-03-20 00:09:20 -04:00
Linus Torvalds
e16b396ce3 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (47 commits)
  doc: CONFIG_UNEVICTABLE_LRU doesn't exist anymore
  Update cpuset info & webiste for cgroups
  dcdbas: force SMI to happen when expected
  arch/arm/Kconfig: remove one to many l's in the word.
  asm-generic/user.h: Fix spelling in comment
  drm: fix printk typo 'sracth'
  Remove one to many n's in a word
  Documentation/filesystems/romfs.txt: fixing link to genromfs
  drivers:scsi Change printk typo initate -> initiate
  serial, pch uart: Remove duplicate inclusion of linux/pci.h header
  fs/eventpoll.c: fix spelling
  mm: Fix out-of-date comments which refers non-existent functions
  drm: Fix printk typo 'failled'
  coh901318.c: Change initate to initiate.
  mbox-db5500.c Change initate to initiate.
  edac: correct i82975x error-info reported
  edac: correct i82975x mci initialisation
  edac: correct commented info
  fs: update comments to point correct document
  target: remove duplicate include of target/target_core_device.h from drivers/target/target_core_hba.c
  ...

Trivial conflict in fs/eventpoll.c (spelling vs addition)
2011-03-18 10:37:40 -07:00
Linus Torvalds
ec0afc9311 Merge branch 'kvm-updates/2.6.39' of git://git.kernel.org/pub/scm/virt/kvm/kvm
* 'kvm-updates/2.6.39' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (55 commits)
  KVM: unbreak userspace that does not sets tss address
  KVM: MMU: cleanup pte write path
  KVM: MMU: introduce a common function to get no-dirty-logged slot
  KVM: fix rcu usage in init_rmode_* functions
  KVM: fix kvmclock regression due to missing clock update
  KVM: emulator: Fix permission checking in io permission bitmap
  KVM: emulator: Fix io permission checking for 64bit guest
  KVM: SVM: Load %gs earlier if CONFIG_X86_32_LAZY_GS=n
  KVM: x86: Remove useless regs_page pointer from kvm_lapic
  KVM: improve comment on rcu use in irqfd_deassign
  KVM: MMU: remove unused macros
  KVM: MMU: cleanup page alloc and free
  KVM: MMU: do not record gfn in kvm_mmu_pte_write
  KVM: MMU: move mmu pages calculated out of mmu lock
  KVM: MMU: set spte accessed bit properly
  KVM: MMU: fix kvm_mmu_slot_remove_write_access dropping intermediate W bits
  KVM: Start lock documentation
  KVM: better readability of efer_reserved_bits
  KVM: Clear async page fault hash after switching to real mode
  KVM: VMX: Initialize vm86 TSS only once.
  ...
2011-03-17 18:40:35 -07:00
Linus Torvalds
7b7adc4a01 Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/epip/linux-2.6-unicore32
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/epip/linux-2.6-unicore32: (40 commits)
  unicore32: rewrite arch-specific tlb.h to use asm-generic version
  unicore32: modify io_p2v and io_v2p macros, and adjust PKUNITY_mmio_BASEs
  unicore32: replace unicore32-specific iomap functions with generic lib implementation
  unicore32 machine related: add frame buffer driver for pkunity-v3 soc
  unicore32 machine related files: add i2c bus drivers for pkunity-v3 soc
  unicore32 io: redefine __REG(x) and re-use readl/writel funcs
  unicore32 i8042 upgrade and bugfix: adjust resource request region type
  unicore32 upgrade to v2.6.38-rc5: add one more paramter for pte_alloc_map call
  unicore32 i8042: adjust io funcs of i8042-unicore32io.h
  unicore32: rename PKUNITY_IOSPACE_BASE to PKUNITY_MMIO_BASE
  unicore32: modify function names and parameters for irq_chips
  unicore32: remove unused lines in arch/unicore32/include/asm/irq.h
  unicore32 time.c: change calculate method for clock_event_device
  unicore32: ADD MAINTAINER for unicore32 architecture
  unicore32 machine related files: ps2 driver
  unicore32 machine related files: pci bus handling
  unicore32 machine related files: hardware registers
  unicore32 machine related files: core files
  unicore32 additional architecture files: boot process
  unicore32 additional architecture files: low-level lib: misc
  ...

Acked-by: Arnd Bergmann <arnd@arndb.de>
2011-03-17 10:11:25 -07:00
Huang Ying
69ebb83e13 mm: make __get_user_pages return -EHWPOISON for HWPOISON page optionally
Make __get_user_pages return -EHWPOISON for HWPOISON page only if
FOLL_HWPOISON is specified.  With this patch, the interested callers
can distinguish HWPOISON pages from general FAULT pages, while other
callers will still get -EFAULT for all these pages, so the user space
interface need not to be changed.

This feature is needed by KVM, where UCR MCE should be relayed to
guest for HWPOISON page, while instruction emulation and MMIO will be
tried for general FAULT page.

The idea comes from Andrew Morton.

Signed-off-by: Huang Ying <ying.huang@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2011-03-17 13:08:27 -03:00
GuanXuetao
7f509a9ef7 asm-generic headers: add arch-specific __strnlen_user calling in uaccess.h
This patch changes the implementation of strnlen_user in include/asm-generic/uaccess.h.
Originally, it calls strlen() function directly, which may not correctly handle the access of
user space in most mmu-enabled architectures.
New __strnlen_user is added for using as an architecture specific function.

Signed-off-by: Guan Xuetao <gxt@mprc.pku.edu.cn>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
2011-03-17 09:19:05 +08:00
GuanXuetao
38f5bf84bd asm-generic headers: add ftrace.h
This patch adds ftrace.h into asm-generic headers.
The file content could be empty in most architectures.

Signed-off-by: Guan Xuetao <gxt@mprc.pku.edu.cn>
Acked-by: Arnd Bergmann <arnd@arndb.de>
2011-03-17 09:19:04 +08:00
GuanXuetao
d232b128e2 asm-generic headers: add sizes.h
This patch adds sizes.h into asm-generic headers.
Only 32-bit version supported.

Signed-off-by: Guan Xuetao <gxt@mprc.pku.edu.cn>
Acked-by: Arnd Bergmann <arnd@arndb.de>
2011-03-17 09:19:04 +08:00
GuanXuetao
7dc59bdde7 asm-generic: fix inX/outX functions for architectures that have PCI
The definitions for the PC-style PIO functions in asm-generic/io.h were
meant as dummies so you could compile code on architectures without
ISA and PCI buses. However, unicore32 actually wants to use them
with a real PCI bus, so they need to be defined to actually address
the register window holding the I/O ports.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2011-03-17 09:19:03 +08:00
Linus Torvalds
e6bee325e4 Merge branch 'tty-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty-2.6
* 'tty-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty-2.6: (76 commits)
  pch_uart: reference clock on CM-iTC
  pch_phub: add new device ML7213
  n_gsm: fix UIH control byte : P bit should be 0
  n_gsm: add a documentation
  serial: msm_serial_hs: Add MSM high speed UART driver
  tty_audit: fix tty_audit_add_data live lock on audit disabled
  tty: move cd1865.h to drivers/staging/tty/
  Staging: tty: fix build with epca.c driver
  pcmcia: synclink_cs: fix prototype for mgslpc_ioctl()
  Staging: generic_serial: fix double locking bug
  nozomi: don't use flush_scheduled_work()
  tty/serial: Relax the device_type restriction from of_serial
  MAINTAINERS: Update HVC file patterns
  tty: phase out of ioctl file pointer for tty3270 as well
  tty: forgot to remove ipwireless from drivers/char/pcmcia/Makefile
  pch_uart: Fix DMA channel miss-setting issue.
  pch_uart: fix exclusive access issue
  pch_uart: fix auto flow control miss-setting issue
  pch_uart: fix uart clock setting issue
  pch_uart : Use dev_xxx not pr_xxx
  ...

Fix up trivial conflicts in drivers/misc/pch_phub.c (same patch applied
twice, then changes to the same area in one branch)
2011-03-16 15:11:04 -07:00
Linus Torvalds
79d8a8f736 Merge branch 'for-2.6.39' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu
* 'for-2.6.39' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu:
  percpu, x86: Add arch-specific this_cpu_cmpxchg_double() support
  percpu: Generic support for this_cpu_cmpxchg_double()
  alpha: use L1_CACHE_BYTES for cacheline size in the linker script
  percpu: align percpu readmostly subsection to cacheline

Fix up trivial conflict in arch/x86/kernel/vmlinux.lds.S due to the
percpu alignment having changed ("x86: Reduce back the alignment of the
per-CPU data section")
2011-03-16 08:22:41 -07:00
Linus Torvalds
9620639b7e Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (26 commits)
  sched: Resched proper CPU on yield_to()
  sched: Allow users with sufficient RLIMIT_NICE to change from SCHED_IDLE policy
  sched: Allow SCHED_BATCH to preempt SCHED_IDLE tasks
  sched: Clean up the IRQ_TIME_ACCOUNTING code
  sched: Add #ifdef around irq time accounting functions
  sched, autogroup: Stop claiming ownership of the root task group
  sched, autogroup: Stop going ahead if autogroup is disabled
  sched, autogroup, sysctl: Use proc_dointvec_minmax() instead
  sched: Fix the group_imb logic
  sched: Clean up some f_b_g() comments
  sched: Clean up remnants of sd_idle
  sched: Wholesale removal of sd_idle logic
  sched: Add yield_to(task, preempt) functionality
  sched: Use a buddy to implement yield_task_fair()
  sched: Limit the scope of clear_buddies
  sched: Check the right ->nr_running in yield_task_fair()
  sched: Avoid expensive initial update_cfs_load(), on UP too
  sched: Fix switch_from_fair()
  sched: Simplify the idle scheduling class
  softirqs: Account ksoftirqd time as cpustat softirq
  ...
2011-03-15 18:37:30 -07:00
Linus Torvalds
a926021cb1 Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (184 commits)
  perf probe: Clean up probe_point_lazy_walker() return value
  tracing: Fix irqoff selftest expanding max buffer
  tracing: Align 4 byte ints together in struct tracer
  tracing: Export trace_set_clr_event()
  tracing: Explain about unstable clock on resume with ring buffer warning
  ftrace/graph: Trace function entry before updating index
  ftrace: Add .ref.text as one of the safe areas to trace
  tracing: Adjust conditional expression latency formatting.
  tracing: Fix event alignment: skb:kfree_skb
  tracing: Fix event alignment: mce:mce_record
  tracing: Fix event alignment: kvm:kvm_hv_hypercall
  tracing: Fix event alignment: module:module_request
  tracing: Fix event alignment: ftrace:context_switch and ftrace:wakeup
  tracing: Remove lock_depth from event entry
  perf header: Stop using 'self'
  perf session: Use evlist/evsel for managing perf.data attributes
  perf top: Don't let events to eat up whole header line
  perf top: Fix events overflow in top command
  ring-buffer: Remove unused #include <linux/trace_irq.h>
  tracing: Add an 'overwrite' trace_option.
  ...
2011-03-15 18:31:30 -07:00
Linus Torvalds
b80cd62b7d Merge branch 'core-futexes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core-futexes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  arm: Remove bogus comment in futex_atomic_cmpxchg_inatomic()
  futex: Deobfuscate handle_futex_death()
  plist: Add priority list test
  plist: Shrink struct plist_head
  futex,plist: Remove debug lock assignment from plist_node
  futex,plist: Pass the real head of the priority list to plist_del()
  futex: Sanitize futex ops argument types
  futex: Sanitize cmpxchg_futex_value_locked API
  futex: Remove redundant pagefault_disable in futex_atomic_cmpxchg_inatomic()
  futex: Avoid redudant evaluation of task_pid_vnr()
  futex: Update futex_wait_setup comments about locking
2011-03-15 18:23:52 -07:00
Al Viro
1abf0c718f New kind of open files - "location only".
New flag for open(2) - O_PATH.  Semantics:
	* pathname is resolved, but the file itself is _NOT_ opened
as far as filesystem is concerned.
	* almost all operations on the resulting descriptors shall
fail with -EBADF.  Exceptions are:
	1) operations on descriptors themselves (i.e.
		close(), dup(), dup2(), dup3(), fcntl(fd, F_DUPFD),
		fcntl(fd, F_DUPFD_CLOEXEC, ...), fcntl(fd, F_GETFD),
		fcntl(fd, F_SETFD, ...))
	2) fcntl(fd, F_GETFL), for a common non-destructive way to
		check if descriptor is open
	3) "dfd" arguments of ...at(2) syscalls, i.e. the starting
		points of pathname resolution
	* closing such descriptor does *NOT* affect dnotify or
posix locks.
	* permissions are checked as usual along the way to file;
no permission checks are applied to the file itself.  Of course,
giving such thing to syscall will result in permission checks (at
the moment it means checking that starting point of ....at() is
a directory and caller has exec permissions on it).

fget() and fget_light() return NULL on such descriptors; use of
fget_raw() and fget_raw_light() is needed to get them.  That protects
existing code from dealing with those things.

There are two things still missing (they come in the next commits):
one is handling of symlinks (right now we refuse to open them that
way; see the next commit for semantics related to those) and another
is descriptor passing via SCM_RIGHTS datagrams.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-03-15 02:21:45 -04:00
Aneesh Kumar K.V
a51571ccb8 unistd.h: Add new syscalls numbers to asm-generic
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-03-15 02:21:45 -04:00
Michel Lespinasse
8d7718aa08 futex: Sanitize futex ops argument types
Change futex_atomic_op_inuser and futex_atomic_cmpxchg_inatomic
prototypes to use u32 types for the futex as this is the data type the
futex core code uses all over the place.

Signed-off-by: Michel Lespinasse <walken@google.com>
Cc: Darren Hart <darren@dvhart.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: David Howells <dhowells@redhat.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <20110311025058.GD26122@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-03-11 12:23:31 +01:00
Michel Lespinasse
37a9d912b2 futex: Sanitize cmpxchg_futex_value_locked API
The cmpxchg_futex_value_locked API was funny in that it returned either
the original, user-exposed futex value OR an error code such as -EFAULT.
This was confusing at best, and could be a source of livelocks in places
that retry the cmpxchg_futex_value_locked after trying to fix the issue
by running fault_in_user_writeable().
    
This change makes the cmpxchg_futex_value_locked API more similar to the
get_futex_value_locked one, returning an error code and updating the
original value through a reference argument.
    
Signed-off-by: Michel Lespinasse <walken@google.com>
Acked-by: Chris Metcalf <cmetcalf@tilera.com>  [tile]
Acked-by: Tony Luck <tony.luck@intel.com>  [ia64]
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Michal Simek <monstr@monstr.eu>  [microblaze]
Acked-by: David Howells <dhowells@redhat.com> [frv]
Cc: Darren Hart <darren@dvhart.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <20110311024851.GC26122@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-03-11 12:23:08 +01:00
Jiri Olsa
ea7145477a x86: Separate out entry text section
Put x86 entry code into a separate link section: .entry.text.

Separating the entry text section seems to have performance
benefits - caused by more efficient instruction cache usage.

Running hackbench with perf stat --repeat showed that the change
compresses the icache footprint. The icache load miss rate went
down by about 15%:

 before patch:
         19417627  L1-icache-load-misses      ( +-   0.147% )

 after patch:
         16490788  L1-icache-load-misses      ( +-   0.180% )

The motivation of the patch was to fix a particular kprobes
bug that relates to the entry text section, the performance
advantage was discovered accidentally.

Whole perf output follows:

 - results for current tip tree:

  Performance counter stats for './hackbench/hackbench 10' (500 runs):

         19417627  L1-icache-load-misses      ( +-   0.147% )
       2676914223  instructions             #      0.497 IPC     ( +- 0.079% )
       5389516026  cycles                     ( +-   0.144% )

      0.206267711  seconds time elapsed   ( +-   0.138% )

 - results for current tip tree with the patch applied:

  Performance counter stats for './hackbench/hackbench 10' (500 runs):

         16490788  L1-icache-load-misses      ( +-   0.180% )
       2717734941  instructions             #      0.502 IPC     ( +- 0.079% )
       5414756975  cycles                     ( +-   0.148% )

      0.206747566  seconds time elapsed   ( +-   0.137% )

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: masami.hiramatsu.pt@hitachi.com
Cc: ananth@in.ibm.com
Cc: davem@davemloft.net
Cc: 2nddept-manager@sdl.hitachi.co.jp
LKML-Reference: <20110307181039.GB15197@jolsa.redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-03-08 17:22:11 +01:00
Ingo Molnar
e0a92c1747 Merge branch 'sched/urgent' into sched/core
Merge reason: Add fixes before applying dependent patches.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-03-04 11:12:26 +01:00
Tobias Klauser
9b4f06fae4 asm-generic/user.h: Fix spelling in comment
Fix two misspellings.

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2011-03-01 15:49:39 +01:00
Ben Hutchings
fbd7184485 mm: <asm-generic/pgtable.h> must include <linux/mm_types.h>
Commit e2cda32264 ("thp: add pmd mangling generic functions") replaced
some macros in <asm-generic/pgtable.h> with inline functions.

If the functions are to be defined (not all architectures need them)
then struct vm_area_struct must be defined first.  So include
<linux/mm_types.h>.

Fixes a build failure seen in Debian:

    CC [M]  drivers/media/dvb/mantis/mantis_pci.o
  In file included from arch/arm/include/asm/pgtable.h:460,
                   from drivers/media/dvb/mantis/mantis_pci.c:25:
  include/asm-generic/pgtable.h: In function 'ptep_test_and_clear_young':
  include/asm-generic/pgtable.h:29: error: dereferencing pointer to incomplete type

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-02-28 17:46:49 -08:00
Greg Kroah-Hartman
f227e08b71 Merge 2.6.38-rc6 into tty-next
This was to resolve a merge issue with drivers/char/Makefile and
drivers/tty/serial/68328serial.c

Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-02-24 11:36:31 -08:00
Kay Sievers
3c95c985fa tty: add TIOCVHANGUP to allow clean tty shutdown of all ttys
This is useful for system management software so that it can kick
off things like gettys and everything that's started from a tty,
before we reuse it from/for something else or shut it down.

Without this ioctl it would have to temporarily become the owner of
the tty, then call vhangup() and then give it up again.

Cc: Lennart Poettering <lennart@poettering.net>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-02-17 14:16:30 -08:00
Ingo Molnar
48fa4b8ecf Merge commit 'v2.6.38-rc5' into sched/core
Merge reason: Pick up upstream fixes.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-02-16 13:31:55 +01:00
Steven Rostedt
3d56e331b6 tracing: Replace syscall_meta_data struct array with pointer array
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 <davem@davemloft.net>
Acked-by: David S. Miller <davem@davemloft.net>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-02-03 09:29:06 -05:00
Mathieu Desnoyers
6549864629 tracepoints: Fix section alignment using pointer array
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 <mathieu.desnoyers@efficios.com>
Acked-by: David S. Miller <davem@davemloft.net>
LKML-Reference: <20110126222622.GA10794@Krystal>
CC: Frederic Weisbecker <fweisbec@gmail.com>
CC: Ingo Molnar <mingo@elte.hu>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Peter Zijlstra <peterz@infradead.org>
CC: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-02-03 09:28:46 -05:00