ARM: 7587/1: implement optimized percpu variable access

Use the previously unused TPIDRPRW register to store percpu offsets.
TPIDRPRW is only accessible in PL1, so it can only be used in the kernel.

This replaces 2 loads with a mrc instruction for each percpu variable
access. With hackbench, the performance improvement is 1.4% on Cortex-A9
(highbank). Taking an average of 30 runs of "hackbench -l 1000" yields:

Before: 6.2191
After: 6.1348

Will Deacon reported similar delta on v6 with 11MPCore.

The asm "memory clobber" are needed here to ensure the percpu offset
gets reloaded. Testing by Will found that this would not happen in
__schedule() which is a bit of a special case as preemption is disabled
but the execution can move cores.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Conflicts:
	arch/arm/include/asm/Kbuild
	arch/arm/kernel/smp.c

Change-Id: Ie143b692a5eea090e615e86e22df90f6ecd7fc2c
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
smp: Add task_struct argument to __cpu_up()

Preparatory patch to make the idle thread allocation for secondary
cpus generic.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Hirokazu Takata <takata@linux-m32r.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: David Howells <dhowells@redhat.com>
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: Richard Weinberger <richard@nod.at>
Cc: x86@kernel.org
Link: http://lkml.kernel.org/r/20120420124556.964170564@linutronix.de

Conflicts:
	arch/arm/kernel/smp.c

Change-Id: Idd1ab4a309918acee2b934fba3de5879663b7fec
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>

Conflicts:
	arch/mn10300/kernel/smp.c
	arch/s390/kernel/smp.c
	include/linux/smp.h
	kernel/cpu.c
arm: Use generic idle thread allocation

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Russell King <linux@arm.linux.org.uk>
Tested-by: Frank Rowand <frank.rowand@am.sony.com>
Link: http://lkml.kernel.org/r/20120420124557.448826362@linutronix.de

Conflicts:
	arch/arm/Kconfig
	arch/arm/kernel/smp.c

Change-Id: I5d578157a22fc7accd152a4515e4dd2c9b086b75
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>

Conflicts:
	arch/arm/kernel/smp.c
ASoC: wcd9320: Handle the port disconnect correctly

In irq handler driver goes through all irq register
status bits to check which interrupt has really
triggered. However hardware sets the irq status register
regardless of mask value set by the driver. This has
an un-intended consequence of stack dump in driver as
it was not expecting this interrupt.

Change-Id: I2fd9ff93134f76cd924fdab7024e712f95caf7fe
Signed-off-by: Anish Kumar <kanish@codeaurora.org>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
ASoC: wcd9xxx: Changes for High performance mode

Add changes for high performance audio playback on headset
for better audio quality during 192KHz/24bit audio playback.

CRs-Fixed: 706322
Change-Id: Ie79293f24114d5d81a610186d24b44b1550dae9c
Signed-off-by: Sudheer Papothi <spapothi@codeaurora.org>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
ASoC: wcd9xxx: Avoid micbias glitches during audio playback

During audio playback over headset, micbias output is switched
to vddio and it's parameters are programmed so that it will do
button polling with a voltage equal to vddio (1.8v). It is observed
that during this polling interval there is a drop in micbias
voltage which would cause issues with button press. Avoid this
voltage drop by disabling mbhc micbias when vddio switch is enabled.

CRs-Fixed: 705060
Change-Id: I0c2f6a0224760aef1f8e51b1ae34c77fc9863b52
Signed-off-by: Phani Kumar Uppalapati <phaniu@codeaurora.org>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>

Conflicts:
	sound/soc/codecs/wcd9xxx-mbhc.c
ARM: 7449/1: use generic strnlen_user and strncpy_from_user functions

This patch implements the word-at-a-time interface for ARM using the
same algorithm as x86. We use the fls macro from ARMv5 onwards, where
we have a clz instruction available which saves us a mov instruction
when targetting Thumb-2. For older CPUs, we use the magic 0x0ff0001
constant. Big-endian configurations make use of the implementation from
asm-generic.

With this implemented, we can replace our byte-at-a-time strnlen_user
and strncpy_from_user functions with the optimised generic versions.

Reviewed-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

lib: Sparc's strncpy_from_user is generic enough, move under lib/

To use this, an architecture simply needs to:

1) Provide a user_addr_max() implementation via asm/uaccess.h

2) Add "select GENERIC_STRNCPY_FROM_USER" to their arch Kcnfig

3) Remove the existing strncpy_from_user() implementation and symbol
   exports their architecture had.

Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: David Howells <dhowells@redhat.com>

lib: add generic strnlen_user() function

This adds a new generic optimized strnlen_user() function that uses the
<asm/word-at-a-time.h> infrastructure to portably do efficient string
handling.

In many ways, strnlen is much simpler than strncpy, and in particular we
can always pre-align the words we load from memory.  That means that all
the worries about alignment etc are a non-issue, so this one can easily
be used on any architecture.  You obviously do have to do the
appropriate word-at-a-time.h macros.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel: Move REPEAT_BYTE definition into linux/kernel.h

And make sure that everything using it explicitly includes
that header file.

Signed-off-by: David S. Miller <davem@davemloft.net>

word-at-a-time: make the interfaces truly generic

This changes the interfaces in <asm/word-at-a-time.h> to be a bit more
complicated, but a lot more generic.

In particular, it allows us to really do the operations efficiently on
both little-endian and big-endian machines, pretty much regardless of
machine details.  For example, if you can rely on a fast population
count instruction on your architecture, this will allow you to make your
optimized <asm/word-at-a-time.h> file with that.

NOTE! The "generic" version in include/asm-generic/word-at-a-time.h is
not truly generic, it actually only works on big-endian.  Why? Because
on little-endian the generic algorithms are wasteful, since you can
inevitably do better. The x86 implementation is an example of that.

(The only truly non-generic part of the asm-generic implementation is
the "find_zero()" function, and you could make a little-endian version
of it.  And if the Kbuild infrastructure allowed us to pick a particular
header file, that would be lovely)

The <asm/word-at-a-time.h> functions are as follows:

 - WORD_AT_A_TIME_CONSTANTS: specific constants that the algorithm
   uses.

 - has_zero(): take a word, and determine if it has a zero byte in it.
   It gets the word, the pointer to the constant pool, and a pointer to
   an intermediate "data" field it can set.

   This is the "quick-and-dirty" zero tester: it's what is run inside
   the hot loops.

 - "prep_zero_mask()": take the word, the data that has_zero() produced,
   and the constant pool, and generate an *exact* mask of which byte had
   the first zero.  This is run directly *outside* the loop, and allows
   the "has_zero()" function to answer the "is there a zero byte"
   question without necessarily getting exactly *which* byte is the
   first one to contain a zero.

   If you do multiple byte lookups concurrently (eg "hash_name()", which
   looks for both NUL and '/' bytes), after you've done the prep_zero_mask()
   phase, the result of those can be or'ed together to get the "either
   or" case.

 - The result from "prep_zero_mask()" can then be fed into "find_zero()"
   (to find the byte offset of the first byte that was zero) or into
   "zero_bytemask()" (to find the bytemask of the bytes preceding the
   zero byte).

   The existence of zero_bytemask() is optional, and is not necessary
   for the normal string routines.  But dentry name hashing needs it, so
   if you enable DENTRY_WORD_AT_A_TIME you need to expose it.

This changes the generic strncpy_from_user() function and the dentry
hashing functions to use these modified word-at-a-time interfaces.  This
gets us back to the optimized state of the x86 strncpy that we lost in
the previous commit when moving over to the generic version.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

ARM: 7450/1: dcache: select DCACHE_WORD_ACCESS for little-endian ARMv6+ CPUs

DCACHE_WORD_ACCESS uses the word-at-a-time API for optimised string
comparisons in the vfs layer.

This patch implements support for load_unaligned_zeropad for ARM CPUs
with native support for unaligned memory accesses (v6+) when running
little-endian.

Change-Id: Ifdf8207f2581f93870eb0e627f5d12f97c4be7cc
Reviewed-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>

Conflicts:
	arch/arm/include/asm/uaccess.h
	arch/arm/kernel/armksyms.c
	arch/arm/lib/Makefile
	arch/x86/include/asm/word-at-a-time.h
	fs/namei.c
Merge branch 'blu' of https://github.com/xboxfanj/android_kernel_htc_msm8974 into blu