modify __down_write[_nested] and __down_write_trylock to grab the write
lock whenever the active count is 0, even if there are queued waiters
(they must be writers pending wakeup, since the active count is 0).

Note that this is an optimization only; architectures without this
optimization will still work fine:

- __down_write() would take the slow path which would take the wait_lock
  and then try stealing the lock (as in the spinlocked rwsem implementation)

- __down_write_trylock() would fail, but callers must be ready to deal
  with that - since there are some writers pending wakeup, they could
  have raced with us and obtained the lock before we steal it.
Signed-off-by: NMichel Lespinasse <walken@google.com>
Reviewed-by: NPeter Hurley <peter@hurleysoftware.com>
Acked-by: NDavidlohr Bueso <davidlohr.bueso@hp.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

If hard_irq_disable() is called while interrupts are already soft-disabled
(which is the most common case) all is already well.

However you can (and in some cases want) to call it while everything is
enabled (to make sure you don't get a lazy even, for example before entry
into KVM guests) and in this case we need to inform the irq tracer that
the irqs are going off.

We have to change the inline into a macro to avoid an include circular
dependency hell hole.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

We are registering the attribute with permission 0600 but it
doesn't have a store callback, which causes WARN_ON's during
boot. Fix the permission.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

The PCI core supports an offset per aperture nowadays but our arch
code still has a single offset per host bridge representing the
difference betwen CPU memory addresses and PCI MMIO addresses.

This is a problem as new machines and hypervisor versions are
coming out where the 64-bit windows will have a different offset
(basically mapped 1:1) from the 32-bit windows.

This fixes it by using separate offsets. In the long run, we probably
want to get rid of that intermediary struct pci_controller and have
those directly stored into the pci_host_bridge as they are parsed
but this will be a more invasive change.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Some devices don't have a correct node ID and thus can't be
attached to an iommu.

The message displayed by the iommu code isn't very useful if
you don't have a device-tree node as it tries to print the
device-tree path but not the struct device name.

Improve this by printing the device name as well.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

We are registering the attribute with permission 0644 but it
doesn't have a store callback, which causes WARN_ON's during
boot. Fix the permission.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Some interrupt controllers refuse to map interrupts marked as
"protected" by firwmare. Since we try to map everyting in the
device-tree on some platforms, we end up with a lot of nasty
WARN's in the boot log for what is a normal situation on those
machines.

This defines a specific return code (-EPERM) from the host map()
callback which cause irqdomain to fail silently.

MPIC is updated to return this when hitting a protected source
printing only a single line message for diagnostic purposes.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

The property should be "ibm,power8-pciex", not "ibm,p8-pciex". The latter
was changed in FW because it was inconsistent with the rest of the nodes.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

When converting to use the new pci_add_resource_offset() we didn't
properly account for empty resources (0 flags) and add those bogons
to the PHBs. The result is some annoying messages in the log.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

If OPAL returns an error, propagate it upward rather than spinning
seconds waiting for a CPU that will never show up
Signed-off-by: NBenjamin Herrenschmidt  <benh@kernel.crashing.org>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Signed-off-by: NNishanth Aravamudan <nacc@us.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Signed-off-by: NNishanth Aravamudan <nacc@us.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Signed-off-by: NNishanth Aravamudan <nacc@us.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Also, make HTM's presence dependent on the .config option.
Signed-off-by: NNishanth Aravamudan <nacc@us.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

On pseries machines the detection for max_bus_speed should be done
through an OpenFirmware property. This patch adds a function to perform
this detection and a hook to perform dynamic adding of the function only
for pseries. This is done by overwriting the weak
pcibios_root_bridge_prepare function which is called by
pci_create_root_bus().

From: Lucas Kannebley Tavares <lucaskt@linux.vnet.ibm.com>
Signed-off-by: NKleber Sacilotto de Souza <klebers@linux.vnet.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

The following patch implements a new PAPR change which allows
the OS to force the use of 32 bit MSIs, regardless of what
the PCI capabilities indicate. This is required for some
devices that advertise support for 64 bit MSIs but don't
actually support them.
Signed-off-by: NBrian King <brking@linux.vnet.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Make sure that current->thread.reg exists before we deference it in
flush_hash_page.
Signed-off-by: NMichael Neuling <mikey@neuling.org>
Reported-by: NJohn J Miller <millerjo@us.ibm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Currently, the OPAL exception vectors are registered before the feature
fixups are processed. This means that the now-firmware-owned vectors
will likely be overwritten by the kernel.

This change moves the exception registration code to an early initcall,
rather than at machine_init time.
Signed-off-by: NJeremy Kerr <jk@ozlabs.org>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

POWER8 allows read and write of the DSCR in userspace. We added
kernel emulation so applications could always use the instructions
regardless of the CPU type.

Unfortunately there are two SPRs for the DSCR and we only added
emulation for the privileged one. Add code to match the non
privileged one.

A simple test was created to verify the fix:

http://ozlabs.org/~anton/junkcode/user_dscr_test.c

Without the patch we get a SIGILL and it passes with the patch.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Cc: <stable@kernel.org>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

We should always have proper privileges when requesting kernel
data.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: <stable@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: eranian@google.com
Link: http://lkml.kernel.org/r/20130503121256.230745028@chello.nl
[ Fix build error reported by fengguang.wu@intel.com, propagate error code back. ]
Signed-off-by: NIngo Molnar <mingo@kernel.org>
Link: http://lkml.kernel.org/n/tip-v0x9ky3ahzr6nm3c6ilwrili@git.kernel.org

Cc: vger.kernel.org
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Cc: stable@vger.kernel.org
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Cc: stable@vger.kernel.org
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Cc: stable@vger.kernel.org
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Cc: stable@vger.kernel.org
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Cc: stable@vger.kernel.org
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Cc: stable@vger.kernel.org
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

This is needed because when scan_of_devices finds the GAISLER_GPTIMER
core that corresponds to the SMP "ticker" timer, the previously set
proper irq flow handler gets overwritten with an incorrect one. This
leads to very flaky timer interrupt handling on some hardware. Proper
updates to handlers can still be done using leon_update_virq_handling.
Signed-off-by: NAndreas Larsson <andreas@gaisler.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The vio_remove() function uses device_find_child() but it does not drop
the reference of the retrieved child.
Signed-off-by: NFederico Vaga <federico.vaga@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

The LBR 'from' adddress is under full userspace control; ensure
we validate it before reading from it.

Note: is_module_text_address() can potentially be quite
expensive; for those running into that with high overhead
in modules optimize it using an RCU backed rb-tree.
Reported-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: <stable@kernel.org>
Cc: eranian@google.com
Link: http://lkml.kernel.org/r/20130503121256.158211806@chello.nlSigned-off-by: NIngo Molnar <mingo@kernel.org>
Link: http://lkml.kernel.org/n/tip-mk8i82ffzax01cnqo829iy1q@git.kernel.org

Errata BV98 states that all MEM_*_RETIRED events corrupt the
counter value of the SMT sibling's counters. Blacklist these
events
Reported-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: <stable@kernel.org>
Cc: eranian@google.com
Link: http://lkml.kernel.org/r/20130503121256.083340271@chello.nlSigned-off-by: NIngo Molnar <mingo@kernel.org>
Link: http://lkml.kernel.org/n/tip-jwra43mujrv1oq9xk6mfe57v@git.kernel.org

Simplify the memory detection code a bit by removing the CHUNK_OLDMEM
and CHUNK_CRASHK memory types.
They are not needed. Everything that is needed is a mechanism to
insert holes into the detected memory.
Reviewed-by: NMichael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Add a notifier for kvm to get control before a page table entry is
invalidated. The notifier is only called for ptes of an address space
with pgstes that have been explicitly marked to require notification.
Kvm will use this to get control before prefix pages of virtual CPU
are unmapped.
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

With VMX, enable_irq_window can now return -EBUSY, in which case an
immediate exit shall be requested before entering the guest. Account for
this also in enable_nmi_window which uses enable_irq_window in absence
of vnmi support, e.g.
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

The new reset controller API is optional, so if that is disabled,
we must not call it from platform code.

arch/arm/mach-imx/built-in.o: In function
 `imx_src_init': /git/arm-soc/arch/arm/mach-imx/src.c:144:
	undefined reference to `reset_controller_register'

Cc: Sascha Hauer <kernel@pengutronix.de>
Signed-off-by: NArnd Bergmann <arnd@arndb.de>

s5p_register_gpio_interrupt() returns 0 or positive for success, and
-ve for errors, so just use the standard >= 0 test.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

device_register() returns -ve values for errors, and zero for success.
There's no need to obfuscate the code with IS_ERR_VALUE().
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Consistently check errors using the usual method used in the kernel
for much of its history.  For instance:

int gpmc_cs_set_timings(int cs, const struct gpmc_timings *t)
{
	int div;
	div = gpmc_calc_divider(t->sync_clk);
	if (div < 0)
		return div;
static int gpmc_set_async_mode(int cs, struct gpmc_timings *t)
{
...
	return gpmc_cs_set_timings(cs, t);

.....
	ret = gpmc_set_async_mode(gpmc_onenand_data->cs, &t);
	if (IS_ERR_VALUE(ret))
		return ret;

So, gpmc_cs_set_timings() thinks any negative return value is an error,
but where we check that in higher levels, only a limited range are
errors...

There is only _one_ use of IS_ERR_VALUE() in arch/arm which is really
appropriate, and that is in arch/arm/include/asm/syscall.h:

static inline long syscall_get_error(struct task_struct *task,
				     struct pt_regs *regs)
{
	unsigned long error = regs->ARM_r0;
	return IS_ERR_VALUE(error) ? error : 0;
}

because this function really does have to differentiate between error
return values and addresses which look like negative numbers (eg, from
mmap()).

So, here's a patch to remove them from OMAP, except for the above.
Acked-by: NTony Lindgren <tony@atomide.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

omap_hwmod_lookup() only returns NULL on error, never an error pointer.
Checking the returned pointer using IS_ERR_OR_NULL() is needless
overhead.  Use a simple !ptr check instead.

OMAP devices (oh->od) always have a valid platform device attached (see
omap_device_alloc()) so there's no point validating the platform device
pointer (we will have already oopsed long before if this is not the
case here.)

Lastly, oh->od is only ever NULL or a valid omap device pointer - 'oh'
comes from the statically declared hwmod tables, and the pointer is
only filled in by omap_device_alloc() at a point where the omap device
pointer must be valid.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>