linux-stable.git/arch/arm/kernel/process.c, branch v3.3

Merge branch 'for-linus' of git://ftp.arm.linux.org.uk/pub/linux/arm/kernel/git-cur/linux-2.6-arm

2012-01-07T02:15:25+00:00

* 'for-linus' of git://ftp.arm.linux.org.uk/pub/linux/arm/kernel/git-cur/linux-2.6-arm: (207 commits)
  ARM: 7267/1: Remove BUILD_BUG_ON from asm/bug.h
  ARM: 7269/1: mach-sa1100: fix sched_clock breakage
  ARM: 7198/1: arm/imx6: add restart support for imx6q
  ARM: restart: remove the now empty arch_reset()
  ARM: restart: remove comments about adding code to arch_reset()
  ARM: restart: lpc32xx & u300: remove unnecessary printk
  ARM: restart: plat-samsung: remove plat/reset.h and s5p_reset_hook
  ARM: restart: w90x900: use new restart hook
  ARM: restart: Versatile Express: use new restart hook
  ARM: restart: versatile: use new restart hook
  ARM: restart: u300: use new restart hook
  ARM: restart: tegra: use new restart hook
  ARM: restart: spear: use new restart hook
  ARM: restart: shark: use new restart hook
  ARM: restart: sa1100: use new restart hook
  ARM: 7252/1: restart: S5PV210: use new restart hook
  ARM: 7251/1: restart: S5PC100: use new restart hook
  ARM: 7250/1: restart: S5P64X0: use new restart hook
  ARM: 7266/1: restart: S3C64XX: use new restart hook
  ARM: 7265/1: restart: S3C24XX: use new restart hook
  ...

Fix up trivial conflict in arch/arm/mm/init.c due to removal of
memblock_init() clashing with the movement of the sorting of the meminfo
array.

Merge branch 'restart' into for-linus

2012-01-05T13:25:27+00:00

Conflicts:
	arch/arm/mach-exynos/cpu.c

The changes to arch/arm/mach-exynos/cpu.c were moved to
mach-exynos/common.c.

ARM: restart: remove the now empty arch_reset()

2012-01-05T12:57:22+00:00

Remove the now empty arch_reset() from all the mach/system.h includes,
and remove its callsite.  Remove arm_machine_restart() as this function
no longer does anything useful.

For samsung platforms, remove the include of mach/system-reset.h and
plat/system-reset.h from their respective mach/system.h headers as these
just define their arch_reset functions.  As a result, the s3c2410 and
plat-samsung system-reset.h files are no longer referenced, so remove
these files entirely.

Acked-by: Nicolas Pitre 
Acked-by: H Hartley Sweeten 
Acked-by: Jamie Iles 
Acked-by: Tony Lindgren 
Acked-by: Linus Walleij 
Signed-off-by: Russell King

Merge branch 'restart-cleanup' into restart

2012-01-05T12:56:44+00:00

Conflicts:
	arch/arm/kernel/setup.c

ARM: reset: implement soft_restart for jumping to a physical address

2011-12-12T16:07:35+00:00

Tools such as kexec and CPU hotplug require a way to reset the processor
and branch to some code in physical space. This requires various bits of
jiggery pokery with the caches and MMU which, when it goes wrong, tends
to lock up the system.

This patch fleshes out the soft_restart implementation so that it
branches to the reset code using the identity mapping. This requires us
to change to a temporary stack, held within the kernel image as a static
array, to avoid conflicting with the new view of memory.

Signed-off-by: Will Deacon

nohz: Remove tick_nohz_idle_enter_norcu() / tick_nohz_idle_exit_norcu()

2011-12-11T18:31:57+00:00

Those two APIs were provided to optimize the calls of
tick_nohz_idle_enter() and rcu_idle_enter() into a single
irq disabled section. This way no interrupt happening in-between would
needlessly process any RCU job.

Now we are talking about an optimization for which benefits
have yet to be measured. Let's start simple and completely decouple
idle rcu and dyntick idle logics to simplify.

Signed-off-by: Frederic Weisbecker 
Cc: Ingo Molnar 
Cc: Thomas Gleixner 
Cc: Peter Zijlstra 
Reviewed-by: Josh Triplett 
Signed-off-by: Paul E. McKenney

nohz: Allow rcu extended quiescent state handling seperately from tick stop

2011-12-11T18:31:36+00:00

It is assumed that rcu won't be used once we switch to tickless
mode and until we restart the tick. However this is not always
true, as in x86-64 where we dereference the idle notifiers after
the tick is stopped.

To prepare for fixing this, add two new APIs:
tick_nohz_idle_enter_norcu() and tick_nohz_idle_exit_norcu().

If no use of RCU is made in the idle loop between
tick_nohz_enter_idle() and tick_nohz_exit_idle() calls, the arch
must instead call the new *_norcu() version such that the arch doesn't
need to call rcu_idle_enter() and rcu_idle_exit().

Otherwise the arch must call tick_nohz_enter_idle() and
tick_nohz_exit_idle() and also call explicitly:

- rcu_idle_enter() after its last use of RCU before the CPU is put
to sleep.
- rcu_idle_exit() before the first use of RCU after the CPU is woken
up.

Signed-off-by: Frederic Weisbecker 
Cc: Mike Frysinger 
Cc: Guan Xuetao 
Cc: David Miller 
Cc: Chris Metcalf 
Cc: Hans-Christian Egtvedt 
Cc: Ralf Baechle 
Cc: Paul E. McKenney 
Cc: Ingo Molnar 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: H. Peter Anvin 
Cc: Russell King 
Cc: Paul Mackerras 
Cc: Heiko Carstens 
Cc: Paul Mundt 
Signed-off-by: Paul E. McKenney

nohz: Separate out irq exit and idle loop dyntick logic

2011-12-11T18:31:35+00:00

The tick_nohz_stop_sched_tick() function, which tries to delay
the next timer tick as long as possible, can be called from two
places:

- From the idle loop to start the dytick idle mode
- From interrupt exit if we have interrupted the dyntick
idle mode, so that we reprogram the next tick event in
case the irq changed some internal state that requires this
action.

There are only few minor differences between both that
are handled by that function, driven by the ts->inidle
cpu variable and the inidle parameter. The whole guarantees
that we only update the dyntick mode on irq exit if we actually
interrupted the dyntick idle mode, and that we enter in RCU extended
quiescent state from idle loop entry only.

Split this function into:

- tick_nohz_idle_enter(), which sets ts->inidle to 1, enters
dynticks idle mode unconditionally if it can, and enters into RCU
extended quiescent state.

- tick_nohz_irq_exit() which only updates the dynticks idle mode
when ts->inidle is set (ie: if tick_nohz_idle_enter() has been called).

To maintain symmetry, tick_nohz_restart_sched_tick() has been renamed
into tick_nohz_idle_exit().

This simplifies the code and micro-optimize the irq exit path (no need
for local_irq_save there). This also prepares for the split between
dynticks and rcu extended quiescent state logics. We'll need this split to
further fix illegal uses of RCU in extended quiescent states in the idle
loop.

Signed-off-by: Frederic Weisbecker 
Cc: Mike Frysinger 
Cc: Guan Xuetao 
Cc: David Miller 
Cc: Chris Metcalf 
Cc: Hans-Christian Egtvedt 
Cc: Ralf Baechle 
Cc: Paul E. McKenney 
Cc: Ingo Molnar 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: H. Peter Anvin 
Cc: Russell King 
Cc: Paul Mackerras 
Cc: Heiko Carstens 
Cc: Paul Mundt 
Signed-off-by: Paul E. McKenney 
Reviewed-by: Josh Triplett

Merge branch 'for-rmk' of git://git.kernel.org/pub/scm/linux/kernel/git/will/linux into devel-stable

2011-12-05T23:20:17+00:00

Conflicts:
	arch/arm/common/gic.c
	arch/arm/plat-omap/include/plat/common.h

ARM: 7161/1: errata: no automatic store buffer drain

2011-11-21T13:12:18+00:00

This patch implements a workaround for PL310 erratum 769419. On
revisions of the PL310 prior to r3p2, the Store Buffer does not
automatically drain. This can cause normal, non-cacheable writes to be
retained when the memory system is idle, leading to suboptimal I/O
performance for drivers using coherent DMA.

This patch adds an optional wmb() call to the cpu_idle loop. On systems
with an outer cache, this causes an explicit flush of the store buffer.

Cc: stable@vger.kernel.org
Acked-by: Catalin Marinas 
Tested-by: Marc Zyngier 
Signed-off-by: Will Deacon 
Signed-off-by: Russell King