Merge branch 'x86/spinlocks' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip into stable/for-linus-3.12

* 'x86/spinlocks' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/kvm/guest: Fix sparse warning: "symbol 'klock_waiting' was not declared as static"
  kvm: Paravirtual ticketlocks support for linux guests running on KVM hypervisor
  kvm guest: Add configuration support to enable debug information for KVM Guests
  kvm uapi: Add KICK_CPU and PV_UNHALT definition to uapi
  xen, pvticketlock: Allow interrupts to be enabled while blocking
  x86, ticketlock: Add slowpath logic
  jump_label: Split jumplabel ratelimit
  x86, pvticketlock: When paravirtualizing ticket locks, increment by 2
  x86, pvticketlock: Use callee-save for lock_spinning
  xen, pvticketlocks: Add xen_nopvspin parameter to disable xen pv ticketlocks
  xen, pvticketlock: Xen implementation for PV ticket locks
  xen: Defer spinlock setup until boot CPU setup
  x86, ticketlock: Collapse a layer of functions
  x86, ticketlock: Don't inline _spin_unlock when using paravirt spinlocks
  x86, spinlock: Replace pv spinlocks with pv ticketlocks

When linux is running as dom0, Xen doesn't show the physical cpu but a
virtual CPU.
On some ARM SOC (for instance the exynos 5250), linux registers callbacks
for cpuidle and cpufreq. When these callbacks are called, they will modify
directly the physical cpu not the virtual one. It can impact the whole board
instead of only dom0.
Signed-off-by: NJulien Grall <julien.grall@linaro.org>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Reviewed-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

m2p_remove_override() calls get_balloon_scratch_page() in
MULTI_update_va_mapping() even though it already has pointer to this page from
the earlier call (in scratch_page). This second call doesn't have a matching
put_balloon_scratch_page() thus not restoring preempt count back. (Also, there
is no put_balloon_scratch_page() in the error path.)

In addition, the second multicall uses __xen_mc_entry() which does not disable
interrupts. Rearrange xen_mc_* calls to keep interrupts off while performing
multicalls.

This commit fixes a regression introduced by:

commit ee072640
Author: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Date:   Tue Jul 23 17:23:54 2013 +0000

    xen/m2p: use GNTTABOP_unmap_and_replace to reinstate the original mapping
Signed-off-by: NBoris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

xen_pm_init was unconditionally setting pm_power_off and arm_pm_restart
function pointers. This breaks multi-platform kernels. Make this
conditional on running as a Xen guest and make it a late_initcall to
ensure it is setup after platform code for Dom0.
Signed-off-by: NRob Herring <rob.herring@calxeda.com>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
CC: stable@vger.kernel.org

kzalloc already adds this __GFP_ZERO.
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Randy reports:

x86_64:

drivers/built-in.o: In function `xen_tpmfront_init':
xen-tpmfront.c:(.init.text+0x257c): undefined reference to `xenbus_register_frontend'

This is nicely fixed by selecting the XenBus frontend module.
Reported-by: NRandy Dunlap <rdunlap@infradead.org>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

In commit cd9151e2: xen/balloon: set a mapping for ballooned out pages
we have the ballooned out page's mapping set to a scratch page.

That commit also sets the P2M entry of ballooned out page to the scratch
page's MFN. This is necessary for PV guest but not for HVM guest. On the
other hand, setting the P2M entry would trigger BUG_ON in
__set_phys_to_machine.

The correct thing to do here is to avoid calling __set_phys_to_machine
for auto translated guest.
Signed-off-by: NWei Liu <wei.liu2@citrix.com>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

The call to del_evtchn() frees "evtchn".
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

When a foreign mapper attempts to map guest frames that are paged out,
the mapper receives an ENOENT response and will have to try again
while a helper process pages the target frame back in.

Gating checks on PRIVCMD_MMAPBATCH* ioctl args were preventing retries
of mapping calls.

Permit subsequent calls to update a sub-range of the VMA, iff nothing
is yet mapped in that range.

Since it is now valid to call PRIVCMD_MMAPBATCH* multiple times, only
set vma->vm_private_data if the parameters are valid and (if
necessary) the pages for the auto_translated_physmap case have been
allocated.  This prevents subsequent calls from incorrectly entering
the 'retry' path when there are no pages allocated etc.
Signed-off-by: NAndres Lagar-Cavilla <andres@lagarcavilla.org>
Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

kernel use callback linked in panic_notifier_list to notice others when panic
happens.
NORET_TYPE void panic(const char * fmt, ...){
    ...
    atomic_notifier_call_chain(&panic_notifier_list, 0, buf);
}
When Xen becomes aware of this, it will call xen_reboot(SHUTDOWN_crash) to
send out an event with reason code - SHUTDOWN_crash.

xen_panic_handler_init() is defined to register on panic_notifier_list but
we only call it in xen_arch_setup which only be called by PV, this patch is
necessary for PVHVM.

Without this patch, setting 'on_crash=coredump-restart' in PVHVM guest config
file won't lead a vmcore to be generate when the guest panics. It can be
reproduced with 'echo c > /proc/sysrq-trigger'.
Signed-off-by: NVaughan Cao <vaughan.cao@oracle.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: NJoe Jin <joe.jin@oracle.com>

GNTTABOP_unmap_grant_ref unmaps a grant and replaces it with a 0
mapping instead of reinstating the original mapping.
Doing so separately would be racy.

To unmap a grant and reinstate the original mapping atomically we use
GNTTABOP_unmap_and_replace.
GNTTABOP_unmap_and_replace doesn't work with GNTMAP_contains_pte, so
don't use it for kmaps.  GNTTABOP_unmap_and_replace zeroes the mapping
passed in new_addr so we have to reinstate it, however that is a
per-cpu mapping only used for balloon scratch pages, so we can be sure that
it's not going to be accessed while the mapping is not valid.
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Reviewed-by: NDavid Vrabel <david.vrabel@citrix.com>
Acked-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
CC: alex@alex.org.uk
CC: dcrisan@flexiant.com

[v1: Konrad fixed up the conflicts]
Conflicts:
	arch/x86/xen/p2m.c

The following commit:

commit 6efa20e4
Author: Konrad Rzeszutek Wilk <konrad@kernel.org>
Date:   Fri Jul 19 11:51:31 2013 -0400

    xen: Support 64-bit PV guest receiving NMIs

breaks the Xen ARM build:

CC      drivers/xen/events.o
drivers/xen/events.c: In function 'xen_send_IPI_one':
drivers/xen/events.c:1218:6: error: 'XEN_NMI_VECTOR' undeclared (first use in this function)

Simply ifdef the undeclared symbol in the code.
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

Jeremy has been a key person in making Linux work with Xen.
He has been enjoying the last year working on something
different so reflect that in the maintainers file.

CC: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: NJeremy Fitzhardinge <jeremy@goop.org>

The original comment on the scanning of the start word on the 2nd pass
did not reflect the actual behaviour (the code was incorrectly masking
bit_idx instead of the pending word itself).

The documented behaviour is not actually required since if event were
pending in the MSBs, they would be immediately scanned anyway as we go
through the loop again.

Update the documentation to reflect this (instead of trying to change
the behaviour).
Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: NBoris Ostrovsky <boris.ostrovsky@oracle.com>

During early setup, when the reserved regions and MMIO holes are being
setup as 1:1 in the p2m, clear any mappings instead of making them 1:1
(execept for the ISA region which is expected to be mapped).

This fixes a regression introduced in 3.5 by 83d51ab4 (xen/setup:
update VA mapping when releasing memory during setup) which caused
hosts with tboot to fail to boot.

tboot marks a region in the e820 map as unusable and the dom0 kernel
would attempt to map this region and Xen does not permit unusable
regions to be mapped by guests.

(XEN)  0000000000000000 - 0000000000060000 (usable)
(XEN)  0000000000060000 - 0000000000068000 (reserved)
(XEN)  0000000000068000 - 000000000009e000 (usable)
(XEN)  0000000000100000 - 0000000000800000 (usable)
(XEN)  0000000000800000 - 0000000000972000 (unusable)

tboot marked this region as unusable.

(XEN)  0000000000972000 - 00000000cf200000 (usable)
(XEN)  00000000cf200000 - 00000000cf38f000 (reserved)
(XEN)  00000000cf38f000 - 00000000cf3ce000 (ACPI data)
(XEN)  00000000cf3ce000 - 00000000d0000000 (reserved)
(XEN)  00000000e0000000 - 00000000f0000000 (reserved)
(XEN)  00000000fe000000 - 0000000100000000 (reserved)
(XEN)  0000000100000000 - 0000000630000000 (usable)
Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

If CONFIG_PREEMPT is enabled then xen_enable_irq() (and
xen_restore_fl()) could be preempted and rescheduled on a different
VCPU in between the clear of the mask and the check for pending
events.  This may result in events being lost as the upcall will check
for pending events on the wrong VCPU.

Fix this by disabling preemption around the unmask and check for
events.
Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

It was not declared as static since it was thought to be used by
pv-flushtlb earlier.
Signed-off-by: NRaghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Cc: <gleb@redhat.com>
Cc: <pbonzini@redhat.com>
Cc: Jiri Kosina <trivial@kernel.org>
Link: http://lkml.kernel.org/r/1376645921-8056-1-git-send-email-raghavendra.kt@linux.vnet.ibm.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

During smp_boot_cpus  paravirtualied KVM guest detects if the hypervisor has
required feature (KVM_FEATURE_PV_UNHALT) to support pv-ticketlocks. If so,
support for pv-ticketlocks is registered via pv_lock_ops.

Use KVM_HC_KICK_CPU hypercall to wakeup waiting/halted vcpu.
Signed-off-by: NSrivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/20130810193849.GA25260@linux.vnet.ibm.comSigned-off-by: NSuzuki Poulose <suzuki@in.ibm.com>
[Raghu: check_zero race fix, enum for kvm_contention_stat, jumplabel related changes,
addition of safe_halt for irq enabled case, bailout spinning in nmi case(Gleb)]
Signed-off-by: NRaghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Acked-by: NGleb Natapov <gleb@redhat.com>
Acked-by: NIngo Molnar <mingo@kernel.org>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

swiotlb-xen has an implicit dependency on CONFIG_NEED_SG_DMA_LENGTH.
Remove it by replacing dma_length with sg_dma_len.
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

This patch replace dma_length in "lib/swiotlb.c" to sg_dma_len() macro,
because the build error can occur if CONFIG_NEED_SG_DMA_LENGTH is not
set, and CONFIG_SWIOTLB is set.
Singed-off-by: NEunBong Song <eunb.song@samsung.com>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Currently ballooned out pages are mapped to 0 and have INVALID_P2M_ENTRY
in the p2m. These ballooned out pages are used to map foreign grants
by gntdev and blkback (see alloc_xenballooned_pages).

Allocate a page per cpu and map all the ballooned out pages to the
corresponding mfn. Set the p2m accordingly. This way reading from a
ballooned out page won't cause a kernel crash (see
http://lists.xen.org/archives/html/xen-devel/2012-12/msg01154.html).
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Reviewed-by: NDavid Vrabel <david.vrabel@citrix.com>
CC: alex@alex.org.uk
CC: dcrisan@flexiant.com
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

The global array of port users and the port_user_lock limits
scalability of the evtchn device.  Instead of the global array lookup,
use a per-use (per-fd) tree of event channels bound by that user and
protect the tree with a per-user lock.

This is also a prerequiste for extended the number of supported event
channels, by removing the fixed size, per-event channel array.
Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

In m2p_remove_override() when removing the grant map from the kernel
mapping and replacing with a mapping to the original page, the grant
unmap will already have flushed the TLB and it is not necessary to do
it again after updating the mapping.
Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

Both Boris and David have graciously volunteered to help in
maintaining the Xen subsystem tree. Cementing this in the
MAINTAINERS file so they are copied on Xen related patches.
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: NBoris Ostrovsky <boris.ostrovsky@oracle.com>
Acked-by: NDavid Vrabel <david.vrabel@citrix.com>

And also drop the virtualization one since we don't really use it.
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com> [for netback]
Acked-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

The usage of strict_strtoul() is not preferred, because
strict_strtoul() is obsolete. Thus, kstrtoul() should be
used.
Signed-off-by: NJingoo Han <jg1.han@samsung.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

With the current implementation, the callback in the tail of the list
can be added twice, because the check done in
gnttab_request_free_callback is bogus, callback->next can be NULL if
it is the last callback in the list. If we add the same callback twice
we end up with an infinite loop, were callback == callback->next.

Replace this check with a proper one that iterates over the list to
see if the callback has already been added.
Signed-off-by: NRoger Pau Monné <roger.pau@citrix.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: NMatt Wilson <msw@amazon.com>
Reviewed-by: NDavid Vrabel <david.vrabel@citrix.com>
CC: stable@vger.kernel.org

This is a complete rewrite of the Xen TPM frontend driver, taking
advantage of a simplified frontend/backend interface and adding support
for cancellation and timeouts.  The backend for this driver is provided
by a vTPM stub domain using the interface in Xen 4.3.
Signed-off-by: NDaniel De Graaf <dgdegra@tycho.nsa.gov>
Acked-by: NMatthew Fioravante <matthew.fioravante@jhuapl.edu>
Reviewed-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: NPeter Huewe <peterhuewe@gmx.de>
Reviewed-by: NPeter Huewe <peterhuewe@gmx.de>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

This is based on a patch that Zhenzhong Duan had sent - which
was missing some of the remaining pieces. The kernel has the
logic to handle Xen-type-exceptions using the paravirt interface
in the assembler code (see PARAVIRT_ADJUST_EXCEPTION_FRAME -
pv_irq_ops.adjust_exception_frame and and INTERRUPT_RETURN -
pv_cpu_ops.iret).

That means the nmi handler (and other exception handlers) use
the hypervisor iret.

The other changes that would be neccessary for this would
be to translate the NMI_VECTOR to one of the entries on the
ipi_vector and make xen_send_IPI_mask_allbutself use different
events.

Fortunately for us commit 1db01b49
(xen: Clean up apic ipi interface) implemented this and we piggyback
on the cleanup such that the apic IPI interface will pass the right
vector value for NMI.

With this patch we can trigger NMIs within a PV guest (only tested
x86_64).

For this to work with normal PV guests (not initial domain)
we need the domain to be able to use the APIC ops - they are
already implemented to use the Xen event channels. For that
to be turned on in a PV domU we need to remove the masking
of X86_FEATURE_APIC.

Incidentally that means kgdb will also now work within
a PV guest without using the 'nokgdbroundup' workaround.

Note that the 32-bit version is different and this patch
does not enable that.

CC: Lisa Nguyen <lisa@xenapiadmin.com>
CC: Ben Guthro <benjamin.guthro@citrix.com>
CC: Zhenzhong Duan <zhenzhong.duan@oracle.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
[v1: Fixed up per David Vrabel comments]
Reviewed-by: NBen Guthro <benjamin.guthro@citrix.com>
Reviewed-by: NDavid Vrabel <david.vrabel@citrix.com>

Signed-off-by: NSrivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/1376058122-8248-14-git-send-email-raghavendra.kt@linux.vnet.ibm.comSigned-off-by: NSuzuki Poulose <suzuki@in.ibm.com>
Signed-off-by: NRaghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Acked-by: NGleb Natapov <gleb@redhat.com>
Acked-by: NIngo Molnar <mingo@kernel.org>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

These are needed by both guest and host.

Originally-from: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Signed-off-by: NRaghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/1376058122-8248-13-git-send-email-raghavendra.kt@linux.vnet.ibm.comAcked-by: NGleb Natapov <gleb@redhat.com>
Acked-by: NIngo Molnar <mingo@kernel.org>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

If interrupts were enabled when taking the spinlock, we can leave them
enabled while blocking to get the lock.

If we can enable interrupts while waiting for the lock to become
available, and we take an interrupt before entering the poll,
and the handler takes a spinlock which ends up going into
the slow state (invalidating the per-cpu "lock" and "want" values),
then when the interrupt handler returns the event channel will
remain pending so the poll will return immediately, causing it to
return out to the main spinlock loop.
Signed-off-by: NJeremy Fitzhardinge <jeremy@goop.org>
Link: http://lkml.kernel.org/r/1376058122-8248-12-git-send-email-raghavendra.kt@linux.vnet.ibm.comReviewed-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: NRaghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Acked-by: NIngo Molnar <mingo@kernel.org>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

Maintain a flag in the LSB of the ticket lock tail which indicates
whether anyone is in the lock slowpath and may need kicking when
the current holder unlocks.  The flags are set when the first locker
enters the slowpath, and cleared when unlocking to an empty queue (ie,
no contention).

In the specific implementation of lock_spinning(), make sure to set
the slowpath flags on the lock just before blocking.  We must do
this before the last-chance pickup test to prevent a deadlock
with the unlocker:

Unlocker			Locker
				test for lock pickup
					-> fail
unlock
test slowpath
	-> false
				set slowpath flags
				block

Whereas this works in any ordering:

Unlocker			Locker
				set slowpath flags
				test for lock pickup
					-> fail
				block
unlock
test slowpath
	-> true, kick

If the unlocker finds that the lock has the slowpath flag set but it is
actually uncontended (ie, head == tail, so nobody is waiting), then it
clears the slowpath flag.

The unlock code uses a locked add to update the head counter.  This also
acts as a full memory barrier so that its safe to subsequently
read back the slowflag state, knowing that the updated lock is visible
to the other CPUs.  If it were an unlocked add, then the flag read may
just be forwarded from the store buffer before it was visible to the other
CPUs, which could result in a deadlock.

Unfortunately this means we need to do a locked instruction when
unlocking with PV ticketlocks.  However, if PV ticketlocks are not
enabled, then the old non-locked "add" is the only unlocking code.

Note: this code relies on gcc making sure that unlikely() code is out of
line of the fastpath, which only happens when OPTIMIZE_SIZE=n.  If it
doesn't the generated code isn't too bad, but its definitely suboptimal.

Thanks to Srivatsa Vaddagiri for providing a bugfix to the original
version of this change, which has been folded in.
Thanks to Stephan Diestelhorst for commenting on some code which relied
on an inaccurate reading of the x86 memory ordering rules.
Signed-off-by: NJeremy Fitzhardinge <jeremy@goop.org>
Link: http://lkml.kernel.org/r/1376058122-8248-11-git-send-email-raghavendra.kt@linux.vnet.ibm.comSigned-off-by: NSrivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Reviewed-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Stephan Diestelhorst <stephan.diestelhorst@amd.com>
Signed-off-by: NRaghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Acked-by: NIngo Molnar <mingo@kernel.org>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

Commit b2029520 ("perf, core: Rate limit
perf_sched_events jump_label patching") introduced rate limiting
for jump label disabling. The changes were made in the jump label code
in order to be more widely available and to keep things tidier. This is
all fine, except now jump_label.h includes linux/workqueue.h, which
makes it impossible to include jump_label.h from anything that
workqueue.h needs. For example, it's now impossible to include
jump_label.h from asm/spinlock.h, which is done in proposed
pv-ticketlock patches. This patch splits out the rate limiting related
changes from jump_label.h into a new file, jump_label_ratelimit.h, to
resolve the issue.
Signed-off-by: NAndrew Jones <drjones@redhat.com>
Link: http://lkml.kernel.org/r/1376058122-8248-10-git-send-email-raghavendra.kt@linux.vnet.ibm.comReviewed-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: NRaghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Acked-by: NIngo Molnar <mingo@kernel.org>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

Increment ticket head/tails by 2 rather than 1 to leave the LSB free
to store a "is in slowpath state" bit.  This halves the number
of possible CPUs for a given ticket size, but this shouldn't matter
in practice - kernels built for 32k+ CPU systems are probably
specially built for the hardware rather than a generic distro
kernel.
Signed-off-by: NJeremy Fitzhardinge <jeremy@goop.org>
Link: http://lkml.kernel.org/r/1376058122-8248-9-git-send-email-raghavendra.kt@linux.vnet.ibm.comReviewed-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Tested-by: NAttilio Rao <attilio.rao@citrix.com>
Signed-off-by: NRaghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Acked-by: NIngo Molnar <mingo@kernel.org>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

Although the lock_spinning calls in the spinlock code are on the
uncommon path, their presence can cause the compiler to generate many
more register save/restores in the function pre/postamble, which is in
the fast path.  To avoid this, convert it to using the pvops callee-save
calling convention, which defers all the save/restores until the actual
function is called, keeping the fastpath clean.
Signed-off-by: NJeremy Fitzhardinge <jeremy@goop.org>
Link: http://lkml.kernel.org/r/1376058122-8248-8-git-send-email-raghavendra.kt@linux.vnet.ibm.comReviewed-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Tested-by: NAttilio Rao <attilio.rao@citrix.com>
Signed-off-by: NRaghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Acked-by: NIngo Molnar <mingo@kernel.org>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

Signed-off-by: NJeremy Fitzhardinge <jeremy@goop.org>
Link: http://lkml.kernel.org/r/1376058122-8248-7-git-send-email-raghavendra.kt@linux.vnet.ibm.comReviewed-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: NRaghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Acked-by: NIngo Molnar <mingo@kernel.org>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

Replace the old Xen implementation of PV spinlocks with and implementation
of xen_lock_spinning and xen_unlock_kick.

xen_lock_spinning simply registers the cpu in its entry in lock_waiting,
adds itself to the waiting_cpus set, and blocks on an event channel
until the channel becomes pending.

xen_unlock_kick searches the cpus in waiting_cpus looking for the one
which next wants this lock with the next ticket, if any.  If found,
it kicks it by making its event channel pending, which wakes it up.

We need to make sure interrupts are disabled while we're relying on the
contents of the per-cpu lock_waiting values, otherwise an interrupt
handler could come in, try to take some other lock, block, and overwrite
our values.
Signed-off-by: NJeremy Fitzhardinge <jeremy@goop.org>
Link: http://lkml.kernel.org/r/1376058122-8248-6-git-send-email-raghavendra.kt@linux.vnet.ibm.comReviewed-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
 [ Raghavendra:  use function + enum instead of macro, cmpxchg for zero status reset
Reintroduce break since we know the exact vCPU to send IPI as suggested by Konrad.]
Signed-off-by: NRaghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Acked-by: NIngo Molnar <mingo@kernel.org>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

There's no need to do it at very early init, and doing it there
makes it impossible to use the jump_label machinery.
Signed-off-by: NJeremy Fitzhardinge <jeremy@goop.org>
Link: http://lkml.kernel.org/r/1376058122-8248-5-git-send-email-raghavendra.kt@linux.vnet.ibm.comReviewed-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: NRaghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Acked-by: NIngo Molnar <mingo@kernel.org>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

Now that the paravirtualization layer doesn't exist at the spinlock
level any more, we can collapse the __ticket_ functions into the arch_
functions.
Signed-off-by: NJeremy Fitzhardinge <jeremy@goop.org>
Link: http://lkml.kernel.org/r/1376058122-8248-4-git-send-email-raghavendra.kt@linux.vnet.ibm.comReviewed-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Tested-by: NAttilio Rao <attilio.rao@citrix.com>
Signed-off-by: NRaghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Acked-by: NIngo Molnar <mingo@kernel.org>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>