linux-toradex.git/arch/s390/kernel/smp.c, branch v3.4.2

[S390] Fix build errors (fallout from system.h disintegration)

2012-03-30T07:41:12+00:00

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

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

2012-03-23T01:15:32+00:00

Pull s390 patches from Martin Schwidefsky:
 "The biggest patch is the rework of the smp code, something I wanted to
  do for some time.  There are some patches for our various dump methods
  and one new thing: z/VM LGR detection.  LGR stands for linux-guest-
  relocation and is the guest migration feature of z/VM.  For debugging
  purposes we keep a log of the systems where a specific guest has lived."

Fix up trivial conflict in arch/s390/kernel/smp.c due to the scheduler
cleanup having removed some code next to removed s390 code.

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
  [S390] kernel: Pass correct stack for smp_call_ipl_cpu()
  [S390] Ensure that vmcore_info pointer is never accessed directly
  [S390] dasd: prevent validate server for offline devices
  [S390] Remove monolithic build option for zcrypt driver.
  [S390] stack dump: fix indentation in output
  [S390] kernel: Add OS info memory interface
  [S390] Use block_sigmask()
  [S390] kernel: Add z/VM LGR detection
  [S390] irq: external interrupt code passing
  [S390] irq: set __ARCH_IRQ_EXIT_IRQS_DISABLED
  [S390] zfcpdump: Implement async sdias event processing
  [S390] Use copy_to_absolute_zero() instead of "stura/sturg"
  [S390] rework idle code
  [S390] rework smp code
  [S390] rename lowcore field
  [S390] Fix gcc 4.6.0 compile warning

[S390] kernel: Pass correct stack for smp_call_ipl_cpu()

2012-03-13T15:26:23+00:00

Currently pcpu_devices->panic_stack is passed to pcpu_delegate() in
smp_call_ipl_cpu(). This is wrong because pcpu_delegate() expects
the bottom (high address) of the stack and pcpu_devices->panic_stack
points to the top (low address). We now pass the bottom of the stack
which is pcpu_devices->panic_stack + PAGE_SIZE.

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

sched: Cleanup cpu_active madness

2012-03-12T19:43:15+00:00

Stepan found:

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.

Reported-by: Stepan Moskovchenko 
Signed-off-by: Peter Zijlstra 
Acked-by: Thomas Gleixner 
Link: http://lkml.kernel.org/r/1323965362.18942.71.camel@twins
Signed-off-by: Ingo Molnar

[S390] kernel: Add OS info memory interface

2012-03-11T15:59:29+00:00

In order to allow kdump based stand-alone dump, some information
has to be passed from the old kernel to the new dump kernel. This
is done via a the struct "os_info" that contains the following fields:
 * crashkernel base and size
 * reipl block
 * vmcoreinfo
 * init function
A pointer to os_info is stored at a well known storage location
and the whole structure as well as all fields are secured with
checksums.

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

[S390] kernel: Add z/VM LGR detection

2012-03-11T15:59:29+00:00

Currently the following mechanisms are available to move active
Linux on System z instances between machines:
* z/VM 6.2 SSI (Single System Image)
* Suspend/resume
For moving Linux instances in this patch the term LGR (Linux Guest
Relocation) is used. Because such an operation is critical, it
should be detectable from Linux. With this patch for both, a live
system and a kernel dump, the information about LGRs is accessible.
To identify a guest, stsi and stfle data is used. A new function
lgr_info_log() compares the current data (lgr_info_cur) with the
last recorded one (lgr_info_last). In case the two data sets differ,
lgr_info_cur is logged to the "lgr" s390dbf.

The following trigger points call lgr_info_log():
* panic
* die
* kdump
* LGR timer
* PSW restart
* QDIO recovery
* resume

This patch also changes the s390dbf hex_ascii view. Now only printable ASCII
characters are shown.

Reviewed-by: Heiko Carstens 
Signed-off-by: Michael Holzheu 
Signed-off-by: Martin Schwidefsky

[S390] irq: external interrupt code passing

2012-03-11T15:59:29+00:00

The external interrupt handlers have a parameter called ext_int_code.
Besides the name this paramter does not only contain the ext_int_code
but in addition also the "cpu address" (POP) which caused the external
interrupt.
To make the code a bit more obvious pass a struct instead so the called
function can easily distinguish between external interrupt code and
cpu address. The cpu address field however is named "subcode" since
some external interrupt sources do not pass a cpu address but a
different parameter (or none at all).

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

[S390] rework idle code

2012-03-11T15:59:28+00:00

Whenever the cpu loads an enabled wait PSW it will appear as idle to the
underlying host system. The code in default_idle calls vtime_stop_cpu
which does the necessary voodoo to get the cpu time accounting right.
The udelay code just loads an enabled wait PSW. To correct this rework
the vtime_stop_cpu/vtime_start_cpu logic and move the difficult parts
to entry[64].S, vtime_stop_cpu can now be called from anywhere and
vtime_start_cpu is gone. The correction of the cpu time during wakeup
from an enabled wait PSW is done with a critical section in entry[64].S.
As vtime_start_cpu is gone, s390_idle_check can be removed as well.

Signed-off-by: Martin Schwidefsky

[S390] rework smp code

2012-03-11T15:59:28+00:00

Define struct pcpu and merge some of the NR_CPUS arrays into it, including
__cpu_logical_map, current_set and smp_cpu_state. Split smp related
functions to those operating on physical cpus and the functions operating
on a logical cpu number. Make the functions for physical cpus use a
pointer to a struct pcpu. This hides the knowledge about cpu addresses in
smp.c, entry[64].S and swsusp_asm64.S, thus remove the sigp.h header.

The PSW restart mechanism is used to start secondary cpus, calling a
function on an online cpu, calling a function on the ipl cpu, and for
the nmi signal. Replace the different assembler functions with a
single function restart_int_handler. The new entry point calls a function
whose pointer is stored in the lowcore of the target cpu and it can wait
for the source cpu to stop. This covers all existing use cases.

Overall the code is now simpler and there are ~380 lines less code.

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

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

2012-01-09T16:11:13+00:00

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (31 commits)
  [S390] disassembler: mark exception causing instructions
  [S390] Enable exception traces by default
  [S390] return address of compat signals
  [S390] sysctl: get rid of dead declaration
  [S390] dasd: fix fixpoint divide exception in define_extent
  [S390] dasd: add sanity check to detect path connection error
  [S390] qdio: fix kernel panic for zfcp 31-bit
  [S390] Add s390x description to Documentation/kdump/kdump.txt
  [S390] Add VMCOREINFO_SYMBOL(high_memory) to vmcoreinfo
  [S390] dasd: fix expiration handling for recovery requests
  [S390] outstanding interrupts vs. smp_send_stop
  [S390] ipc: call generic sys_ipc demultiplexer
  [S390] zcrypt: Fix error return codes.
  [S390] zcrypt: Rework length parameter checking.
  [S390] cleanup trap handling
  [S390] Remove Kerntypes leftovers
  [S390] topology: increase poll frequency if change is anticipated
  [S390] entry[64].S improvements
  [S390] make arch/s390 subdirectories depend on config option
  [S390] kvm: move cmf host id constant out of lowcore
  ...

Fix up conflicts in arch/s390/kernel/{smp.c,topology.c} due to the
sysdev removal clashing with "topology: get rid of ifdefs" which moved
some of that code around.