linux-toradex.git/arch/powerpc/include/asm/bitops.h, branch v3.3.5

powerpc: Fix atomic_xxx_return barrier semantics

2011-11-17T05:26:07+00:00

The Documentation/memory-barriers.txt document requires that atomic
operations that return a value act as a memory barrier both before
and after the actual atomic operation.

Our current implementation doesn't guarantee this. More specifically,
while a load following the isync can not be issued before stwcx. has
completed, that completion doesn't architecturally means that the
result of stwcx. is visible to other processors (or any previous stores
for that matter) (typically, the other processors L1 caches can still
hold the old value).

This has caused an actual crash in RCU torture testing on Power 7

This fixes it by changing those atomic ops to use new macros instead
of RELEASE/ACQUIRE barriers, called ATOMIC_ENTRY and ATMOIC_EXIT barriers,
which are then defined respectively to lwsync and sync.

I haven't had a chance to measure the performance impact (or rather
what I measured with kernel compiles is in the noise, I yet have to
find a more precise benchmark)

Signed-off-by: Benjamin Herrenschmidt 
Acked-by: Paul E. McKenney

asm-generic: add another generic ext2 atomic bitops

2011-07-26T23:49:46+00:00

The majority of architectures implement ext2 atomic bitops as
test_and_{set,clear}_bit() without spinlock.

This adds this type of generic implementation in ext2-atomic-setbit.h and
use it wherever possible.

Signed-off-by: Akinobu Mita 
Suggested-by: Andreas Dilger 
Suggested-by: Arnd Bergmann 
Acked-by: Arnd Bergmann 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Fix common misspellings

2011-03-31T14:26:23+00:00

Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi

bitops: remove minix bitops from asm/bitops.h

2011-03-24T02:46:22+00:00

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 
Acked-by: Arnd Bergmann 
Acked-by: Greg Ungerer 
Cc: Geert Uytterhoeven 
Cc: Roman Zippel 
Cc: Andreas Schwab 
Cc: Martin Schwidefsky 
Cc: Heiko Carstens 
Cc: Yoshinori Sato 
Cc: Michal Simek 
Cc: "David S. Miller" 
Cc: Hirokazu Takata 
Acked-by: Ralf Baechle 
Acked-by: Paul Mundt 
Cc: Chris Zankel 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

bitops: remove ext2 non-atomic bitops from asm/bitops.h

2011-03-24T02:46:21+00:00

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 
Cc: Jan Kara 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

powerpc: introduce little-endian bitops

2011-03-24T02:46:12+00:00

Introduce little-endian bit operations by renaming existing powerpc native
little-endian bit operations and changing them to take any pointer types.

Signed-off-by: Akinobu Mita 
Cc: Benjamin Herrenschmidt 
Cc: Paul Mackerras 
Cc: "H. Peter Anvin" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

asm-generic: change little-endian bitops to take any pointer types

2011-03-24T02:46:12+00:00

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 
Cc: Arnd Bergmann 
Cc: Richard Henderson 
Cc: Ivan Kokshaysky 
Cc: Mikael Starvik 
Cc: David Howells 
Cc: Yoshinori Sato 
Cc: "Luck, Tony" 
Cc: Ralf Baechle 
Cc: Kyle McMartin 
Cc: Matthew Wilcox 
Cc: Grant Grundler 
Cc: Paul Mundt 
Cc: Kazumoto Kojima 
Cc: Hirokazu Takata 
Cc: "David S. Miller" 
Cc: Chris Zankel 
Cc: Ingo Molnar 
Cc: Thomas Gleixner 
Cc: Hans-Christian Egtvedt 
Cc: "H. Peter Anvin" 
Cc: Benjamin Herrenschmidt 
Cc: Paul Mackerras 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

asm-generic: rename generic little-endian bitops functions

2011-03-24T02:46:11+00:00

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 
Acked-by: Arnd Bergmann 
Acked-by: Hans-Christian Egtvedt 
Cc: Geert Uytterhoeven 
Cc: Roman Zippel 
Cc: Andreas Schwab 
Cc: Greg Ungerer 
Cc: Benjamin Herrenschmidt 
Cc: Paul Mackerras 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

powerpc: Add support for popcnt instructions

2010-11-29T04:48:17+00:00

POWER5 added popcntb, and POWER7 added popcntw and popcntd. As a first step
this patch does all the work out of line, but it would be nice to implement
them as inlines with an out of line fallback.

The performance issue with hweight was noticed when disabling SMT on a large
(192 thread) POWER7 box. The patch improves that testcase by about 8%.

Signed-off-by: Anton Blanchard 
Signed-off-by: Benjamin Herrenschmidt

powerpc: Rename LWSYNC_ON_SMP to PPC_RELEASE_BARRIER, ISYNC_ON_SMP to PPC_ACQUIRE_BARRIER

2010-02-17T03:03:15+00:00

For performance reasons we are about to change ISYNC_ON_SMP to sometimes be
lwsync. Now that the macro name doesn't make sense, change it and LWSYNC_ON_SMP
to better explain what the barriers are doing.

Signed-off-by: Anton Blanchard 
Signed-off-by: Benjamin Herrenschmidt