In external time-travel mode, where time is controlled via the
controller application socket, interrupt handling is a little
tricky. For example on virtio, the following happens:
* we receive a message (that requires an ACK) on the vhost-user socket
* we add a time-travel event to handle the interrupt
(this causes communication on the time socket)
* we ACK the original vhost-user message
* we then handle the interrupt once the event is triggered
This protocol ensures that the sender of the interrupt only continues
to run in the simulation when the time-travel event has been added.
So far, this was only done in the virtio driver, but it was actually
wrong, because only virtqueue interrupts were handled this way, and
config change interrupts were handled immediately. Additionally, the
messages were actually handled in the real Linux interrupt handler,
but Linux interrupt handlers are part of the simulation and shouldn't
run while there's no time event.
To really do this properly and only handle all kinds of interrupts in
the time-travel event when we are scheduled to run in the simulation,
rework this to plug in to the lower interrupt layers in UML directly:
Add a um_request_irq_tt() function that let's a time-travel aware
driver request an interrupt with an additional timetravel_handler()
that is called outside of the context of the simulation, to handle
the message only. It then adds an event to the time-travel calendar
if necessary, and no "real" Linux code runs outside of the time
simulation.
This also hooks in with suspend/resume properly now, since this new
timetravel_handler() can run while Linux is suspended and interrupts
are disabled, and decide to wake up (or not) the system based on the
message it received. Importantly in this case, it ACKs the message
before the system even resumes and interrupts are re-enabled, thus
allowing the simulation to progress properly.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
We don't actually use this in um_request_irq(), so it can
never be assigned. It's also not clear what that would be
useful for, so just remove it.
This results in quite a number of cleanups, all the way to
removing the "SIGIO on close" startup check, since the data
it assigns (pty_close_sigio) is not used anymore.
While at it, also make this an enum so we get a minimum of
type checking, and remove the IRQ_NONE hack in virtio since
we now no longer have the name twice.
Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
It's cumbersome and error-prone to keep adding fixed IRQ numbers,
and for proper device wakeup support for the virtio/vhost-user
support we need to have different IRQs for each device. Even if
in theory two IRQs (with and without wake) might be sufficient,
it's much easier to reason about it when we have dynamic number
assignment. It also makes it easier to add new devices that may
dynamically exist or depending on the configuration, etc.
Add support for this, up to 64 IRQs (the same limit as epoll FDs
we have right now). Since it's not easy to port all the existing
places to dynamic allocation (some data is statically initialized)
keep the low numbers are reserved for the existing hard-coded IRQ
numbers.
Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Convert files to use SPDX header. All files are licensed under the GPLv2.
Signed-off-by: Alex Dewar <alex.dewar@gmx.co.uk>
Signed-off-by: Richard Weinberger <richard@nod.at>
Instead of using chip->release() we can achieve the same
using a simple wrapper for free_irq().
We have already um_request_irq(), so um_free_irq() is the perfect
counterpart.
Signed-off-by: Richard Weinberger <richard@nod.at>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
These comments are useless now, remove them.
Signed-off-by: WANG Cong <xiyou.wangcong@gmail.com>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We can't just plop asm/* into it - userland helpers are built with it
in search path and seeing asm/* show up there suddenly would be a bad
idea.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2008-10-22 22:55:19 -07:00
Renamed from arch/um/include/irq_kern.h (Browse further)
