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  1. 25 5月, 2012 3 次提交
  3. 21 5月, 2012 1 次提交
  5. 28 3月, 2012 1 次提交
  7. 21 3月, 2012 1 次提交
  9. 16 3月, 2012 1 次提交
  11. 14 3月, 2012 3 次提交
  13. 09 3月, 2012 3 次提交
  15. 27 1月, 2012 1 次提交
    • A
      serial: Kill off NO_IRQ · d4e33fac
      由 Alan Cox 提交于 
      We transform the offenders into a test of irq <= 0 which will be ok while
the ARM people get their platform sorted. Once that is done (or in a while
if they don't do it anyway) then we will change them all to !irq checks.

For arch specific drivers that are already using NO_IRQ = 0 we just test
against zero so we don't need to re-review them later.
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
      d4e33fac
  17. 16 11月, 2011 1 次提交
    • S
      tty: hvc_dcc: Fix duplicate character inputs · c2a3e84f
      由 Stephen Boyd 提交于 
      Reading from the DCC grabs a character from the buffer and
clears the status bit. Since this is a context-changing
operation, instructions following the character read that rely on
the status bit being accurate need to be synchronized with an
ISB.

In this case, the status bit check needs to execute after the
character read otherwise we run the risk of reading the character
and checking the status bit before the read can clear the status
bit in the first place. When this happens, the user will see the
same character they typed twice, instead of once.

Add an ISB after the read and the write, so that the status check
is synchronized with the read/write operations.
Signed-off-by: NStephen Boyd <sboyd@codeaurora.org>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
      c2a3e84f
  19. 07 11月, 2011 2 次提交
  21. 01 11月, 2011 1 次提交
  23. 19 10月, 2011 1 次提交
  25. 23 9月, 2011 1 次提交
  27. 20 9月, 2011 2 次提交
  29. 26 8月, 2011 1 次提交
  31. 20 7月, 2011 1 次提交
  33. 19 7月, 2011 3 次提交
  35. 01 7月, 2011 1 次提交
  37. 29 6月, 2011 4 次提交
    • B
      powerpc/pseries: Move hvsi support into a library · 17bdc6c0
      由 Benjamin Herrenschmidt 提交于 
      This will allow a different backend to share it
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
      17bdc6c0
    • B
      powerpc/pseries: Re-implement HVSI as part of hvc_vio · 4d2bb3f5
      由 Benjamin Herrenschmidt 提交于 
      On pseries machines, consoles are provided by the hypervisor using
a low level get_chars/put_chars type interface. However, this is
really just a transport to the service processor which implements
them either as "raw" console (networked consoles, HMC, ...) or as
"hvsi" serial ports.

The later is a simple packet protocol on top of the raw character
interface that is supposed to convey additional "serial port" style
semantics. In practice however, all it does is provide a way to
read the CD line and set/clear our DTR line, that's it.

We currently implement the "raw" protocol as an hvc console backend
(/dev/hvcN) and the "hvsi" protocol using a separate tty driver
(/dev/hvsi0).

However this is quite impractical. The arbitrary difference between
the two type of devices has been a major source of user (and distro)
confusion. Additionally, there's an additional mini -hvsi implementation
in the pseries platform code for our low level debug console and early
boot kernel messages, which means code duplication, though that low
level variant is impractical as it's incapable of doing the initial
protocol negociation to establish the link to the FSP.

This essentially replaces the dedicated hvsi driver and the platform
udbg code completely by extending the existing hvc_vio backend used
in "raw" mode so that:

 - It now supports HVSI as well
 - We add support for hvc backend providing tiocm{get,set}
 - It also provides a udbg interface for early debug and boot console

This is overall less code, though this will only be obvious once we
remove the old "hvsi" driver, which is still available for now. When
the old driver is enabled, the new code still kicks in for the low
level udbg console, replacing the old mini implementation in the platform
code, it just doesn't provide the higher level "hvc" interface.

In addition to producing generally simler code, this has several benefits
over our current situation:

 - The user/distro only has to deal with /dev/hvcN for the hypervisor
console, avoiding all sort of confusion that has plagued us in the past

 - The tty, kernel and low level debug console all use the same code
base which supports the full protocol establishment process, thus the
console is now available much earlier than it used to be with the
old HVSI driver. The kernel console works much earlier and udbg is
available much earlier too. Hackers can enable a hard coded very-early
debug console as well that works with HVSI (previously that was only
supported for the "raw" mode).

I've tried to keep the same semantics as hvsi relative to how I react
to things like CD changes, with some subtle differences though:

 - I clear DTR on close if HUPCL is set

 - Current hvsi triggers a hangup if it detects a up->down transition
   on CD (you can still open a console with CD down). My new implementation
   triggers a hangup if the link to the FSP is severed, and severs it upon
   detecting a up->down transition on CD.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
      4d2bb3f5
    • B
      powerpc/pseries: Factor HVSI header struct in packet definitions · 048bee77
      由 Benjamin Herrenschmidt 提交于 
      Embed the struct hvsi_header in the various packet definitions
rather than open coding it multiple times. Will help provide
stronger type checking.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
      048bee77
    • B
      powerpc/hvsi: Move HVSI protocol definitions to a header file · 725e789f
      由 Benjamin Herrenschmidt 提交于 
      This moves various HVSI protocol definitions from the hvsi.c
driver to a header file that can be used later on by a udbg
implementation
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
      725e789f
  39. 31 3月, 2011 1 次提交
  41. 29 3月, 2011 1 次提交
  43. 10 3月, 2011 1 次提交
    • K
      xen/hvc: Disable probe_irq_on/off from poking the hvc-console IRQ line. · bbd5a762
      由 Konrad Rzeszutek Wilk 提交于 
      This fixes a particular nasty racing problem found when using
Xen hypervisor with the console (hvc) output being routed to the
serial port and the serial port receiving data when
probe_irq_off(probe_irq_on) is running.

Specifically the bug manifests itself with:

[    4.470693] BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
[    4.470693] IP: [<ffffffff810a8c65>] handle_IRQ_event+0xe/0xc9
..snip..
[    4.470693] Call Trace:
[    4.470693]  <IRQ>
[    4.470693]  [<ffffffff810aa645>] handle_percpu_irq+0x3c/0x69
[    4.470693]  [<ffffffff8123cda7>] __xen_evtchn_do_upcall+0xfd/0x195
[    4.470693]  [<ffffffff810308cf>] ? xen_restore_fl_direct_end+0x0/0x1
[    4.470693]  [<ffffffff8123d873>] xen_evtchn_do_upcall+0x32/0x47
[    4.470693]  [<ffffffff81034dfe>] xen_do_hypervisor_callback+0x1e/0x30
[    4.470693]  <EOI>
[    4.470693]  [<ffffffff8100922a>] ? hypercall_page+0x22a/0x1000
[    4.470693]  [<ffffffff8100922a>] ? hypercall_page+0x22a/0x1000
[    4.470693]  [<ffffffff810301c5>] ? xen_force_evtchn_callback+0xd/0xf
[    4.470693]  [<ffffffff810308e2>] ? check_events+0x12/0x20
[    4.470693]  [<ffffffff81030889>] ? xen_irq_enable_direct_end+0x0/0x7
[    4.470693]  [<ffffffff810ab0a0>] ? probe_irq_on+0x8f/0x1d7
[    4.470693]  [<ffffffff812b105e>] ? serial8250_config_port+0x7b7/0x9e6
[    4.470693]  [<ffffffff812ad66c>] ? uart_add_one_port+0x11b/0x305

The bug is trigged by three actors working together:
 A). serial_8250_config_port calling
	probe_irq_off(probe_irq_on())
     wherein all of the IRQ handlers are being started and shut off.
     The functions utilize the sleep functions so the minimum time
     they are run is 120 msec.
 B). Xen hypervisor receiving on the serial line any character and
     setting the bits in the event channel - during this 120 msec timeframe.
 C). The hvc API makes a call to 'request_irq' (and hence setting desc->action
     to a valid value), much much later - when user space opens
     /dev/console (hvc_open). To make the console usable during bootup,
     the Xen HVC implementation sets the IRQ chip (and correspondingly
     the event channel) much earlier. The IRQ chip handler that is used
     is the handle_percpu_irq (aaca4964)

Back to the issue. When A) is being called it ends up calling the
xen_percpu_chip's chip->startup twice and chip->shutdown once. Those
are set to the default_startup and mask_irq (events.c) respectivly.
If (and this seems to depend on what serial concentrator you use), B)
gets data from the serial port it sets in the event channel a pending bit.
When A) calls chip->startup(), the masking of the pending bit, and
unmasking of the event channel mask, and also setting of the upcall_pending
flag is done (since there is data present on the event channel).
If before the 120 msec has elapsed, any IRQ handler (Xen IRQ has one
IRQ handler, which checks the event channels bitmap to figure which one
to call) is called we end up calling the handle_percpu_irq. The
handle_percpu_irq calls desc->action (which is NULL) and we blow up.

Caveats: I could only reproduce this on 2.6.32 pvops. I am not sure
why this is not showing up on 2.6.38 kernel.

The probe_irq_on/off has code to disable poking specific IRQ lines. This is
done by using the set_irq_noprobe() and then we do not have to
worry about the handle_percpu_irq being called before the IRQ action
handler has been installed.
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      bbd5a762
  45. 02 3月, 2011 1 次提交
    • B
      powerpc/pseries: Reduce HVCS driver insanity · c7704d35
      由 Benjamin Herrenschmidt 提交于 
      The HVCS driver, for those who don't know, is a driver for the "server" side
of the IBM virtual terminal mechanism allowing Linux partitions to act as
terminal servers under IBM PowerVM hypervisor. It's almost never used on
the field at the moment.

However, it's part of our configs, and in its current incarnation, will
allocate the tty driver & major (with 64 minors) and create a kernel thread
whether it's used or not, ie, whether the hypervisor did put a virtual
terminal server device node in the partition or not (or whether running on
a pseries machine or not even).

This in turns causes modern distro's udev's to start trying to open all
those 64 minors at boot, which, since they aren't linked to anything,
causes the driver to spew errors in the kernel log for each of them.

Not nice.

This moves all that initialization to a function which is now only called
the first time a terminal server virtual IO device is actually probed
(that is almost never).

There's still a _LOT_ of cleanup that can be done in this driver, some
simple (almost all printk's statements in there shall either just be
removed or in some case turned into better written & more informative
messages, including using the dev_* variants etc...). This is left as
an exercise for whoever actually cares about that driver.

One could also try to be smart and dispose of all the tty related
resources when the last instance of the VIO server device
is removed (Hotplug anybody ?).
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
      c7704d35
  47. 23 2月, 2011 1 次提交
  49. 18 2月, 2011 3 次提交