linux-toradex.git/include/xen/events.h, branch v3.15.10

xen: add support for MSI message groups

2014-03-18T14:40:09+00:00

Add support for MSI message groups for Xen Dom0 using the
MAP_PIRQ_TYPE_MULTI_MSI pirq map type.

In order to keep track of which pirq is the first one in the group all
pirqs in the MSI group except for the first one have the newly
introduced PIRQ_MSI_GROUP flag set. This prevents calling
PHYSDEVOP_unmap_pirq on them, since the unmap must be done with the
first pirq in the group.

Signed-off-by: Roger Pau Monné 
Signed-off-by: David Vrabel 
Cc: Boris Ostrovsky

xen/events: remove the unused resend_irq_on_evtchn()

2014-02-28T20:26:16+00:00

resend_irq_on_evtchn() was only used by ia64 (which no longer has Xen
support).

Signed-off-by: David Vrabel 
Signed-off-by: Konrad Rzeszutek Wilk 
Reviewed-by: Boris Ostrovsky

xen/events: allow event channel priority to be set

2014-01-06T15:07:54+00:00

Add xen_irq_set_priority() to set an event channels priority.  This function
will only work with event channel ABIs that support priority (i.e., the
FIFO-based ABI).

Signed-off-by: David Vrabel 
Reviewed-by: Konrad Rzeszutek Wilk 
Reviewed-by: Boris Ostrovsky

xen/evtchn: support more than 4096 ports

2014-01-06T15:07:50+00:00

Remove the check during unbind for NR_EVENT_CHANNELS as this limits
support to less than 4096 ports.

Signed-off-by: David Vrabel 
Reviewed-by: Konrad Rzeszutek Wilk 
Reviewed-by: Boris Ostrovsky

xen/events: move 2-level specific code into its own file

2014-01-06T15:07:41+00:00

In preparation for alternative event channel ABIs, move all the
functions accessing the shared data structures into their own file.

Signed-off-by: David Vrabel 
Reviewed-by: Konrad Rzeszutek Wilk 
Reviewed-by: Boris Ostrovsky

x86, trace: Add irq vector tracepoints

2013-06-21T05:25:34+00:00

[Purpose of this patch]

As Vaibhav explained in the thread below, tracepoints for irq vectors
are useful.

http://www.spinics.net/lists/mm-commits/msg85707.html


The current interrupt traces from irq_handler_entry and irq_handler_exit
provide when an interrupt is handled.  They provide good data about when
the system has switched to kernel space and how it affects the currently
running processes.

There are some IRQ vectors which trigger the system into kernel space,
which are not handled in generic IRQ handlers.  Tracing such events gives
us the information about IRQ interaction with other system events.

The trace also tells where the system is spending its time.  We want to
know which cores are handling interrupts and how they are affecting other
processes in the system.  Also, the trace provides information about when
the cores are idle and which interrupts are changing that state.


On the other hand, my usecase is tracing just local timer event and
getting a value of instruction pointer.

I suggested to add an argument local timer event to get instruction pointer before.
But there is another way to get it with external module like systemtap.
So, I don't need to add any argument to irq vector tracepoints now.

[Patch Description]

Vaibhav's patch shared a trace point ,irq_vector_entry/irq_vector_exit, in all events.
But there is an above use case to trace specific irq_vector rather than tracing all events.
In this case, we are concerned about overhead due to unwanted events.

So, add following tracepoints instead of introducing irq_vector_entry/exit.
so that we can enable them independently.
   - local_timer_vector
   - reschedule_vector
   - call_function_vector
   - call_function_single_vector
   - irq_work_entry_vector
   - error_apic_vector
   - thermal_apic_vector
   - threshold_apic_vector
   - spurious_apic_vector
   - x86_platform_ipi_vector

Also, introduce a logic switching IDT at enabling/disabling time so that a time penalty
makes a zero when tracepoints are disabled. Detailed explanations are as follows.
 - Create trace irq handlers with entering_irq()/exiting_irq().
 - Create a new IDT, trace_idt_table, at boot time by adding a logic to
   _set_gate(). It is just a copy of original idt table.
 - Register the new handlers for tracpoints to the new IDT by introducing
   macros to alloc_intr_gate() called at registering time of irq_vector handlers.
 - Add checking, whether irq vector tracing is on/off, into load_current_idt().
   This has to be done below debug checking for these reasons.
   - Switching to debug IDT may be kicked while tracing is enabled.
   - On the other hands, switching to trace IDT is kicked only when debugging
     is disabled.

In addition, the new IDT is created only when CONFIG_TRACING is enabled to avoid being
used for other purposes.

Signed-off-by: Seiji Aguchi 
Link: http://lkml.kernel.org/r/51C323ED.5050708@hds.com
Signed-off-by: H. Peter Anvin 
Cc: Steven Rostedt

xen: drop tracking of IRQ vector

2013-04-16T19:05:45+00:00

For quite a few Xen versions, this wasn't the IRQ vector anymore
anyway, and it is not being used by the kernel for anything. Hence
drop the field from struct irq_info, and respective function
parameters.

Signed-off-by: Jan Beulich 
Acked-by: Stefano Stabellini 
Signed-off-by: Konrad Rzeszutek Wilk

xen/arm: receive Xen events on ARM

2012-09-14T13:37:32+00:00

Compile events.c on ARM.
Parse, map and enable the IRQ to get event notifications from the device
tree (node "/xen").

Signed-off-by: Stefano Stabellini 
Acked-by: Konrad Rzeszutek Wilk

xen: do not map the same GSI twice in PVHVM guests.

2012-05-21T18:11:36+00:00

PV on HVM guests map GSIs into event channels. At restore time the
event channels are resumed by restore_pirqs.

Device drivers might try to register the same GSI again through ACPI at
restore time, but the GSI has already been mapped and bound by
restore_pirqs. This patch detects these situations and avoids
 mapping the same GSI multiple times.

Without this patch we get:
(XEN) irq.c:2235: dom4: pirq 23 or emuirq 28 already mapped
and waste a pirq.

CC: stable@kernel.org
Signed-off-by: Stefano Stabellini 
Signed-off-by: Konrad Rzeszutek Wilk

xen/event: Add reference counting to event channels

2011-11-21T22:14:48+00:00

Event channels exposed to userspace by the evtchn module may be used by
other modules in an asynchronous manner, which requires that reference
counting be used to prevent the event channel from being closed before
the signals are delivered.

The reference count on new event channels defaults to -1 which indicates
the event channel is not referenced outside the kernel; evtchn_get fails
if called on such an event channel. The event channels made visible to
userspace by evtchn have a normal reference count.

Signed-off-by: Daniel De Graaf 
Signed-off-by: Konrad Rzeszutek Wilk