This patch eliminates a potential deadlock that is possible when XPC
disconnects a channel to a partition that has gone down. This deadlock will
occur if at least one of the kthreads created by XPC for the purpose of making
callouts to the channel's registerer is detained in the registerer and will
not be returning back to XPC until some registerer request occurs on the now
downed partition. The potential for a deadlock is removed by ensuring that
there always is a kthread available to make the channel disconnecting callout
to the registerer.
Signed-off-by: Dean Nelson <dcn@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Jack Steiner identified a problem where XPC can cause a silent
data corruption. On module load, the placement may cause the
xpc_remote_copy_buffer to span two physical pages. DMA transfers are
done to the start virtual address translated to physical.
This patch changes the buffer from a statically allocated buffer to a
kmalloc'd buffer. Dean Nelson reviewed this before posting. I have
tested it in the configuration that was showing the memory corruption
and verified it works. I also added a BUG_ON statement to help catch
this if a similar situation is encountered.
Signed-off-by: Robin Holt <holt@sgi.com>
Signed-off-by: Dean Nelson <dcn@sgi.com>
Signed-off-by: Jack Steiner <steiner@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Fix some sparse warnings on ia64. Large constants that should be long
instead of int. Use NULL instead of 0. Add some missing __iomem
casts. Replace a non-C99 structure assignment.
Signed-off-by: Keith Owens <kaos@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Take advantage of kzalloc() as well as reduce the size of code generated
for the error returns in xpc_setup_infrastructure().
Signed-off-by: Jes Sorensen <jes@sgi.com>
Acked-by: Dean Nelson <dcn@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Fix XPC so that it does not deliver any messages until the connected
callout has returned, as well as, prevent the disconnected callout to
occur before the disconnecting callout has returned.
Signed-off-by: Dean Nelson <dcn@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
During some testing, we got a warning about trying to allocate
memory while holding a lock. This fixes that problem.
Signed-off-by: Robin Holt <holt@sgi.com>
Acked-by: Dean Nelson <dcn@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Migrate sn2 code to use mutex and completion events rather than
semaphores.
Signed-off-by: Jes Sorensen <jes@sgi.com>
Acked-by: Dean Nelson <dcn@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Cleanup a few items after moving xpc.h from arch/ia64/sn/kernel to
include/asm-ia64/sn.
Signed-off-by: Dean Nelson <dcn@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Move xpc_system_reboot() to be closer to the file it calls for readability
reasons (which are indeed subjective).
Signed-off-by: Dean Nelson <dcn@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Allow for the loss of heartbeat while in kdebug to be ignored by remote
partitions.
Signed-off-by: Dean Nelson <dcn@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Cleanup the XPC disengage related messages that are printed to the log.
Signed-off-by: Dean Nelson <dcn@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
This patch fixes a problem in XPC disengage processing whereby it was not
seeing the request to disengage from a remote partition, so the disengage
wasn't happening. The disengagement is suppose to transpire during the time
a XPC channel is disconnecting, and should be completed before the channel
is declared to be disconnected.
Signed-off-by: Dean Nelson <dcn@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
XPC (as in arch/ia64/sn/kernel/xp*) has a need to notify other partitions
(SGI Altix) whenever a partition is going down in order to get them to
disengage from accessing the halting partition's memory. If this is not
done before the reset of the hardware, the other partitions can find
themselves encountering MCAs that bring them down.
Signed-off-by: Dean Nelson <dcn@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
XPC needs to be changed to support up to 16k nasids on an SGI Altix system.
Signed-off-by: Dean Nelson <dcn@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
This patch addresses a few issues with the open/close protocol that
were revealed by the newly added disengage functionality combined
with more extensive testing.
Signed-off-by: Dean Nelson <dcn@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
These are SN2 only drivers. They should have platform checks to prevent
them from doing evil stuff in GENERIC kernels.
Signed-off-by: Martin Hicks <mort@sgi.com>
Acked-by: Dean Nelson <dcn@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
When XPC is being shutdown (i.e., rmmod, reboot) it doesn't ensure that
other partitions with whom it was connected have completely disengaged
from any attempt at cross-partition memory references. This can lead to
MCAs in any of these other partitions when the partition is reset.
Signed-off-by: Dean Nelson <dcn@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Here's the patch again to fix the code to handle if the values between
MAX_USER_RT_PRIO and MAX_RT_PRIO are different.
Without this patch, an SMP system will crash if the values are
different.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Dean Nelson <dcn@sgi.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Description: Replace schedule_timeout() with msleep_interruptible() to
guarantee the task delays as expected.
Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com>
Acked-by: Dean Nelson <dcn@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
This patch contains the communication module (XPC) for cross partition
communication on a partitioned SGI Altix.
Signed-off-by: Dean Nelson <dcn@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Dean Nelson