linux-stable.git/arch/s390/kernel/processor.c, branch linux-4.7.y

s390: add missing include statements

2016-05-10T11:24:52+00:00

arch_mmap_rnd, cpu_have_feature, and arch_randomize_brk are all
defined as globally visible variables.
However the files they are defined in do not include the header files
with the declaration. To avoid a possible mismatch add the missing
include statements so we have proper type checking in place.

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

s390/cpuinfo: simplify locking and skip offline cpus early

2016-05-10T11:24:48+00:00

Move the get_online_cpus() and put_online_cpus() to the start and stop
operation of the seqfile ops. This way there is no need to lock cpu
hotplug again and again for each single cpu.

This way we can also skip offline cpus early if we simply use
cpumask_next() within the next operation.

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

s390: show virtualization support in /proc/cpuinfo

2015-11-30T11:47:11+00:00

This patch exposes the SIE capability (aka virtualization support) via
/proc/cpuinfo -> "features" as "sie".

As we don't want to expose this hwcap via elf, let's add a second,
"internal"/non-elf capability list. The content is simply concatenated
to the existing features when printing /proc/cpuinfo.

We also add the defines to elf.h to keep the hwcap stuff at a common
place.

Acked-by: Martin Schwidefsky 
Signed-off-by: David Hildenbrand 
Signed-off-by: Christian Borntraeger

s390/diag: add a statistic for diagnose calls

2015-10-14T12:32:06+00:00

Introduce /sys/debug/kernel/diag_stat with a statistic how many diagnose
calls have been done by each CPU in the system.

Signed-off-by: Martin Schwidefsky

s390/module: enable generic CPU feature modalias using s390 ELF hwcaps

2015-07-22T07:58:02+00:00

Add support for the generic CPU feature modalias implementation that wires
up optional CPU features to udev-based module autoprobing.

The  file provides definitions to map CPU features to
s390 ELF hardware capabilities.

Signed-off-by: Hendrik Brueckner 
Signed-off-by: Martin Schwidefsky

s390/ftrace: fix crashes when switching tracers / add notrace to cpu_relax()

2015-03-02T19:35:53+00:00

With git commit 4d92f50249eb ("s390: reintroduce diag 44 calls for
cpu_relax()") I reintroduced a non-trivial cpu_relax() variant on s390.

The difference to the previous variant however is that the new version is
an out-of-line function, which will be traced if function tracing is enabled.

Switching to different tracers includes instruction patching. Therefore this
is done within stop_machine() "context" to prevent that any function tracing
is going on while instructions are being patched.
With the new out-of-line variant of cpu_relax() this is not true anymore,
since cpu_relax() gets called in a busy loop by all waiting cpus within
stop_machine() until function patching is finished.
Therefore cpu_relax() must be marked notrace.

This fixes kernel crashes when frequently switching between "function" and
"function_graph" tracers.

Moving cpu_relax() to a header file again, doesn't work because of header
include order dependencies.

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

s390: reintroduce diag 44 calls for cpu_relax()

2015-01-29T08:19:16+00:00

Christian Borntraeger reported that the now missing diag 44 calls (voluntary
time slice end) does cause a performance regression for stop_machine() calls
if a machine has more virtual cpus than the host has physical cpus.

This patch mainly reverts 57f2ffe14fd125c2 ("s390: remove diag 44 calls from
cpu_relax()") with the exception that we still do not issue diag 44 calls if
running with smt enabled. Due to group scheduling algorithms when running in
LPAR this would lead to significant latencies.
However, when running in LPAR we do not have more virtual than physical cpus.

Reported-and-tested-by: Christian Borntraeger 
Signed-off-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky

Merge branch 'for-3.18-consistent-ops' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu

2014-10-15T05:48:18+00:00

Pull percpu consistent-ops changes from Tejun Heo:
"Way back, before the current percpu allocator was implemented, static
and dynamic percpu memory areas were allocated and handled separately
and had their own accessors. The distinction has been gone for many
years now; however, the now duplicate two sets of accessors remained
with the pointer based ones - this_cpu_*() - evolving various other
operations over time. During the process, we also accumulated other
inconsistent operations.

This pull request contains Christoph's patches to clean up the
duplicate accessor situation. __get_cpu_var() uses are replaced with
with this_cpu_ptr() and __this_cpu_ptr() with raw_cpu_ptr().

Unfortunately, the former sometimes is tricky thanks to C being a bit
messy with the distinction between lvalues and pointers, which led to
a rather ugly solution for cpumask_var_t involving the introduction of
this_cpu_cpumask_var_ptr().

This converts most of the uses but not all. Christoph will follow up
with the remaining conversions in this merge window and hopefully
remove the obsolete accessors"

* 'for-3.18-consistent-ops' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: (38 commits)
irqchip: Properly fetch the per cpu offset
percpu: Resolve ambiguities in __get_cpu_var/cpumask_var_t -fix
ia64: sn_nodepda cannot be assigned to after this_cpu conversion. Use __this_cpu_write.
percpu: Resolve ambiguities in __get_cpu_var/cpumask_var_t
Revert "powerpc: Replace __get_cpu_var uses"
percpu: Remove __this_cpu_ptr
clocksource: Replace __this_cpu_ptr with raw_cpu_ptr
sparc: Replace __get_cpu_var uses
avr32: Replace __get_cpu_var with __this_cpu_write
blackfin: Replace __get_cpu_var uses
tile: Use this_cpu_ptr() for hardware counters
tile: Replace __get_cpu_var uses
powerpc: Replace __get_cpu_var uses
alpha: Replace __get_cpu_var
ia64: Replace __get_cpu_var uses
s390: cio driver &__get_cpu_var replacements
s390: Replace __get_cpu_var uses
mips: Replace __get_cpu_var uses
MIPS: Replace __get_cpu_var uses in FPU emulator.
arm: Replace __this_cpu_ptr with raw_cpu_ptr
...

s390: add support for vector extension

2014-10-09T07:14:13+00:00

The vector extension introduces 32 128-bit vector registers and a set of
instruction to operate on the vector registers.

The kernel can control the use of vector registers for the problem state
program with a bit in control register 0. Once enabled for a process the
kernel needs to retain the content of the vector registers on context
switch. The signal frame is extended to include the vector registers.
Two new register sets NT_S390_VXRS_LOW and NT_S390_VXRS_HIGH are added
to the regset interface for the debugger and core dumps.

Signed-off-by: Martin Schwidefsky

s390/vtime: do not reset idle data on CPU hotplug

2014-10-09T07:13:58+00:00

The sysfs attributes /sys/devices/system/cpu/cpu0/idle_count and
/sys/devices/system/cpu/cpu0/idle_time_us are reset to zero every
time a CPU is set online. The idle and iowait fields in /proc/stat
corresponding to idle_time_us are not reset. To make things
consistent do not reset the data for the sys attributes.

Signed-off-by: Martin Schwidefsky