linux-toradex.git/arch/s390/kernel, branch tegra

cpu-hotplug: CPUx should be active before it is marked online

2011-12-27T05:28:19+00:00

CPU0		CPUn

_cpu_up()
  __cpu_up()

		boostrap()
		  notify_cpu_starting()
		  set_cpu_online()
		  while (!cpu_active())
		    cpu_relax()



smp_call_function(.wait=1)
  /* we find cpu_online() is true */
  arch_send_call_function_ipi_mask()
  /* wait-forever-more */

		  local_irq_enable()

  cpu_notify(CPU_ONLINE)
    sched_cpu_active()
      set_cpu_active()

Now the purpose of cpu_active is mostly with bringing down a cpu, where
we mark it !active to avoid the load-balancer from moving tasks to it
while we tear down the cpu. This is required because we only update the
sched_domain tree after we brought the cpu-down. And this is needed so
that some tasks can still run while we bring it down, we just don't want
new tasks to appear.

On cpu-up however the sched_domain tree doesn't yet include the new cpu,
so its invisible to the load-balancer, regardless of the active state.
So instead of setting the active state after we boot the new cpu (and
consequently having to wait for it before enabling interrupts) set the
cpu active before we set it online and avoid the whole mess.

Bug 916986

Original Patch: https://lkml.org/lkml/2011/12/15/255

Change-Id: Ia1c07bdc1b3eb07a7cd4d69756fa7bec509c9400
Reported-by: Stepan Moskovchenko 
Signed-off-by: Peter Zijlstra 
Signed-off-by: Varun Wadekar 
Reviewed-on: http://git-master/r/72130
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Mayuresh Kulkarni

add missing .set function for NT_S390_LAST_BREAK regset

2011-12-09T16:55:45+00:00

commit b934069c991355d27a053a932591c77960f4e414 upstream.

The last breaking event address is a read-only value, the regset misses the
.set function. If a PTRACE_SETREGSET is done for NT_S390_LAST_BREAK we
get an oops due to a branch to zero:

Kernel BUG at 0000000000000002 verbose debug info unavailable
illegal operation: 0001 #1 SMP
...
Call Trace:
(<0000000000158294> ptrace_regset+0x184/0x188)
 <00000000001595b6> ptrace_request+0x37a/0x4fc
 <0000000000109a78> arch_ptrace+0x108/0x1fc
 <00000000001590d6> SyS_ptrace+0xaa/0x12c
 <00000000005c7a42> sysc_noemu+0x16/0x1c
 <000003fffd5ec10c> 0x3fffd5ec10c
Last Breaking-Event-Address:
 <0000000000158242> ptrace_regset+0x132/0x188

Add a nop .set function to prevent the branch to zero.

Signed-off-by: Martin Schwidefsky 
Signed-off-by: Greg Kroah-Hartman

user per registers vs. ptrace single stepping

2011-11-11T17:43:22+00:00

commit a45aff5285871bf7be1781d9462d3fdbb6c913f9 upstream.

git commit 5e9a2692 "[S390] ptrace cleanup" introduced a regression
for the case when both a user PER set (e.g. a storage alteration trace) and
PTRACE_SINGLESTEP are active. The new code will overrule the user PER set
with a instruction-fetch PER set over the whole address space for ptrace
single stepping. The inferior process will be stopped after each instruction
with an instruction fetch event. Any other events that may have occurred
concurrently are not reported (e.g. storage alteration event) because the
control bits for them are not set. The solution is to merge the PER control
bits of the user PER set with the PER_EVENT_IFETCH control bit for
PTRACE_SINGLESTEP.

Signed-off-by: Martin Schwidefsky 
Signed-off-by: Greg Kroah-Hartman

[S390] kvm: fix address mode switching

2011-09-20T15:07:34+00:00

598841ca9919d008b520114d8a4378c4ce4e40a1 ([S390] use gmap address
spaces for kvm guest images) changed kvm to use a separate address
space for kvm guests. This address space was switched in __vcpu_run
In some cases (preemption, page fault) there is the possibility that
this address space switch is lost.
The typical symptom was a huge amount of validity intercepts or
random guest addressing exceptions.
Fix this by doing the switch in sie_loop and sie_exit and saving the
address space in the gmap structure itself. Also use the preempt
notifier.

Signed-off-by: Christian Borntraeger 
Acked-by: Avi Kivity 
Signed-off-by: Heiko Carstens

All Arch: remove linkage for sys_nfsservctl system call

2011-08-26T22:09:58+00:00

The nfsservctl system call is now gone, so we should remove all
linkage for it.

Signed-off-by: NeilBrown 
Signed-off-by: J. Bruce Fields 
Signed-off-by: Linus Torvalds

[S390] Change default action from reipl to stop for on_restart

2011-08-24T15:15:24+00:00

The main purpose for PSW restart will be kdump. Therefore customers will
issue "system restart" for creating a dump. If kdump is not enabled,
currently "PSW restart" will reboot the system and then no dump can
be created any more. In order to still allow a manual stand-alone dump in
the case a user issues "PSW restart" on a system that has not enabled
kdump we now stop the system.

Signed-off-by: Michael Holzheu 
Signed-off-by: Martin Schwidefsky

[S390] arch/s390/kernel/ipl.c: correct error detection check

2011-08-24T15:15:24+00:00

reipl_fcp_kset was just initialized, so it appears that it should be tested
instead of reipl_kset.

Signed-off-by: Julia Lawall 
Reported-by: Suman Saha 
Signed-off-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky

[S390] nss,initrd: kernel image and initrd must be in different segments

2011-08-24T15:15:23+00:00

When IPL'ing from a block device and an NSS should be created we must
make sure that the kernel image and the initrd are in different 1MB
segments. Otherwise creating the NSS will fail.
So we make sure the initrd is 4MB behind the end of the kernel image
like we do already when IPL via the VM reader is performed.

Signed-off-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky

[S390] signal: use set_restore_sigmask() helper

2011-08-03T14:44:21+00:00

We should call set_restore_sigmask() instead of directly setting
TIF_RESTORE_SIGMASK. This change should have been done three years
earlier... see 4e4c22 "signals: add set_restore_sigmask".

Signed-off-by: Heiko Carstens

[S390] smp: remove pointless comments in startup_secondary()

2011-08-03T14:44:21+00:00

Remove pointless comments in startup_secondary(). There is not too much
value in having comments like e.g. "call cpu notifiers" just before a
call to notify_cpu*().

Signed-off-by: Heiko Carstens