linux-stable.git/drivers/tty/hvc, branch linux-3.4.y

xen/events: don't bind non-percpu VIRQs with percpu chip

2015-09-18T01:20:42+00:00

commit 77bb3dfdc0d554befad58fdefbc41be5bc3ed38a upstream.

A non-percpu VIRQ (e.g., VIRQ_CONSOLE) may be freed on a different
VCPU than it is bound to.  This can result in a race between
handle_percpu_irq() and removing the action in __free_irq() because
handle_percpu_irq() does not take desc->lock.  The interrupt handler
sees a NULL action and oopses.

Only use the percpu chip/handler for per-CPU VIRQs (like VIRQ_TIMER).

  # cat /proc/interrupts | grep virq
   40:      87246          0  xen-percpu-virq      timer0
   44:          0          0  xen-percpu-virq      debug0
   47:          0      20995  xen-percpu-virq      timer1
   51:          0          0  xen-percpu-virq      debug1
   69:          0          0   xen-dyn-virq      xen-pcpu
   74:          0          0   xen-dyn-virq      mce
   75:         29          0   xen-dyn-virq      hvc_console

Signed-off-by: David Vrabel 
[lizf: Backported to 3.4: adjust filename]
Signed-off-by: Zefan Li

xen/console: Update console event channel on resume

2015-09-18T01:20:36+00:00

commit b9d934f27c91b878c4b2e64299d6e419a4022f8d upstream.

After a resume the hypervisor/tools may change console event
channel number. We should re-query it.

Signed-off-by: Boris Ostrovsky 
Signed-off-by: David Vrabel 
Signed-off-by: Zefan Li

drivers/tty/hvc: don't free hvc_console_setup after init

2014-05-13T12:11:29+00:00

commit 501fed45b7e8836ee9373f4d31e2d85e3db6103a upstream.

When 'console=hvc0' is specified to the kernel parameter in x86 KVM guest,
hvc console is setup within a kthread. However, that will cause SEGV
and the boot will fail when the driver is builtin to the kernel,
because currently hvc_console_setup() is annotated with '__init'. This
patch removes '__init' to boot the guest successfully with 'console=hvc0'.

Signed-off-by: Tomoki Sekiyama 
Signed-off-by: Greg Kroah-Hartman

hvc: ensure hvc_init is only ever called once in hvc_console.c

2014-05-06T14:51:45+00:00

commit f76a1cbed18c86e2d192455f0daebb48458965f3 upstream.

Commit 3e6c6f630a5282df8f3393a59f10eb9c56536d23 ("Delay creation of
khcvd thread") moved the call of hvc_init from being a device_initcall
into hvc_alloc, and used a non-null hvc_driver as indication of whether
hvc_init had already been called.

The problem with this is that hvc_driver is only assigned a value
at the bottom of hvc_init, and so there is a window where multiple
hvc_alloc calls can be in progress at the same time and hence try
and call hvc_init multiple times.  Previously the use of device_init
guaranteed that hvc_init was only called once.

This manifests itself as sporadic instances of two hvc_init calls
racing each other, and with the loser of the race getting -EBUSY
from tty_register_driver() and hence that virtual console fails:

    Couldn't register hvc console driver
    virtio-ports vport0p1: error -16 allocating hvc for port

Here we add an atomic_t to guarantee we'll never run hvc_init twice.

Cc: Rusty Russell 
Cc: Greg Kroah-Hartman 
Fixes: 3e6c6f630a52 ("Delay creation of khcvd thread")
Reported-by: Jim Somerville 
Tested-by: Jim Somerville 
Signed-off-by: Paul Gortmaker 
Signed-off-by: Greg Kroah-Hartman

powerpc/hvsi: Increase handshake timeout from 200ms to 400ms.

2013-09-08T04:58:14+00:00

commit d220980b701d838560a70de691b53be007e99e78 upstream.

This solves a problem observed in kexec'ed kernel where 200ms timeout is
too short and bootconsole fails to initialize. Console did eventually
become workable but much later into the boot process.

Observed timeout was around 260ms, but I decided to make it a little bigger
for more reliability.

This has been tested on Power7 machine with Petitboot as a primary
bootloader and PowerNV firmware.

Signed-off-by: Eugene Surovegin 
Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Greg Kroah-Hartman

xen/hvc: Check HVM_PARAM_CONSOLE_[EVTCHN|PFN] for correctness.

2012-06-22T18:36:54+00:00

commit 5842f5768599094758931b74190cdf93641a8e35 upstream.

We need to make sure that those parameters are setup to be correct.
As such the value of 0 is deemed invalid and we find that we
bail out. The hypervisor sets by default all of them to be zero
and when the hypercall is done does a simple:

 a.value = d->arch.hvm_domain.params[a.index];

Which means that if the Xen toolstack forgot to setup the proper
HVM_PARAM_CONSOLE_EVTCHN (or the PFN one), we would get the
default value of 0 and use that.

Fixes-Oracle-Bug: 14091238
Signed-off-by: Konrad Rzeszutek Wilk 
Signed-off-by: Greg Kroah-Hartman

xen/hvc: Fix error cases around HVM_PARAM_CONSOLE_PFN

2012-06-22T18:36:53+00:00

commit a32c88b9386ce3df87f28dd46bdc3776cd6edf75 upstream.

We weren't resetting the parameter to be passed in to a
known default. Nor were we checking the return value of
hvm_get_parameter.

Signed-off-by: Konrad Rzeszutek Wilk 
Signed-off-by: Greg Kroah-Hartman

xen/hvc: Collapse error logic.

2012-06-22T18:36:53+00:00

commit 2e5ad6b9c45d43cc4e7b8ac5ded1c55a7c4a3893 upstream.

All of the error paths are doing the same logic. In which
case we might as well collapse them in one path.

Acked-by: Stefano Stabellini 
Signed-off-by: Konrad Rzeszutek Wilk 
Signed-off-by: Greg Kroah-Hartman

hvc_xen: NULL dereference on allocation failure

2012-06-01T07:18:25+00:00

commit 201a52bea928687b7557728b176ac4f8a37d5cbd upstream.

If kzalloc() returns a NULL here, we pass a NULL to
xencons_disconnect_backend() which will cause an Oops.

Also I removed the __GFP_ZERO while I was at it since kzalloc() implies
__GFP_ZERO.

Acked-by: Stefano Stabellini 
Signed-off-by: Dan Carpenter 
Signed-off-by: Konrad Rzeszutek Wilk 
Signed-off-by: Greg Kroah-Hartman

powerpc+sparc/vio: Modernize driver registration

2012-03-28T00:33:24+00:00

This makes vio_register_driver() get the module owner & name at compile
time like PCI drivers do, and adds a name pointer directly in struct
vio_driver to avoid having to explicitly initialize the embedded
struct device.

Signed-off-by: Benjamin Herrenschmidt 
Acked-by: David S. Miller