linux-stable.git/arch/s390/include/asm/processor.h, branch v4.2

s390: remove 31 bit support

2015-03-25T10:49:33+00:00

Remove the 31 bit support in order to reduce maintenance cost and
effectively remove dead code. Since a couple of years there is no
distribution left that comes with a 31 bit kernel.

The 31 bit kernel also has been broken since more than a year before
anybody noticed. In addition I added a removal warning to the kernel
shown at ipl for 5 minutes: a960062e5826 ("s390: add 31 bit warning
message") which let everybody know about the plan to remove 31 bit
code. We didn't get any response.

Given that the last 31 bit only machine was introduced in 1999 let's
remove the code.
Anybody with 31 bit user space code can still use the compat mode.

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

s390: remove diag 44 calls from cpu_relax()

2014-11-28T08:47:49+00:00

Simplify cpu_relax() to a simple barrier(). Performance wise this doesn't
seem to make any big difference anymore, since nearly all lock variants
have directed yield semantics in the meantime.
Also this makes s390 behave like all other architectures.

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

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/idle: consolidate idle functions and definitions

2014-10-09T07:14:03+00:00

Move the C functions and definitions related to the idle state handling
to arch/s390/include/asm/idle.h and arch/s390/kernel/idle.c. The function
s390_get_idle_time is renamed to arch_cpu_idle_time and vtime_stop_cpu to
enabled_wait.

Signed-off-by: Martin Schwidefsky

s390/nohz: use a per-cpu flag for arch_needs_cpu

2014-10-09T07:14:02+00:00

Move the nohz_delay bit from the s390_idle data structure to the
per-cpu flags. Clear the nohz delay flag in __cpu_disable and
remove the cpu hotplug notifier that used to do this.

Signed-off-by: Martin Schwidefsky

arch, locking: Ciao arch_mutex_cpu_relax()

2014-07-17T10:32:47+00:00

The arch_mutex_cpu_relax() function, introduced by 34b133f, is
hacky and ugly. It was added a few years ago to address the fact
that common cpu_relax() calls include yielding on s390, and thus
impact the optimistic spinning functionality of mutexes. Nowadays
we use this function well beyond mutexes: rwsem, qrwlock, mcs and
lockref. Since the macro that defines the call is in the mutex header,
any users must include mutex.h and the naming is misleading as well.

This patch (i) renames the call to cpu_relax_lowlatency  ("relax, but
only if you can do it with very low latency") and (ii) defines it in
each arch's asm/processor.h local header, just like for regular cpu_relax
functions. On all archs, except s390, cpu_relax_lowlatency is simply cpu_relax,
and thus we can take it out of mutex.h. While this can seem redundant,
I believe it is a good choice as it allows us to move out arch specific
logic from generic locking primitives and enables future(?) archs to
transparently define it, similarly to System Z.

Signed-off-by: Davidlohr Bueso 
Signed-off-by: Peter Zijlstra 
Cc: Andrew Morton 
Cc: Anton Blanchard 
Cc: Aurelien Jacquiot 
Cc: Benjamin Herrenschmidt 
Cc: Bharat Bhushan 
Cc: Catalin Marinas 
Cc: Chen Liqin 
Cc: Chris Metcalf 
Cc: Christian Borntraeger 
Cc: Chris Zankel 
Cc: David Howells 
Cc: David S. Miller 
Cc: Deepthi Dharwar 
Cc: Dominik Dingel 
Cc: Fenghua Yu 
Cc: Geert Uytterhoeven 
Cc: Guan Xuetao 
Cc: Haavard Skinnemoen 
Cc: Hans-Christian Egtvedt 
Cc: Heiko Carstens 
Cc: Helge Deller 
Cc: Hirokazu Takata 
Cc: Ivan Kokshaysky 
Cc: James E.J. Bottomley 
Cc: James Hogan 
Cc: Jason Wang 
Cc: Jesper Nilsson 
Cc: Joe Perches 
Cc: Jonas Bonn 
Cc: Joseph Myers 
Cc: Kees Cook 
Cc: Koichi Yasutake 
Cc: Lennox Wu 
Cc: Linus Torvalds 
Cc: Mark Salter 
Cc: Martin Schwidefsky 
Cc: Matt Turner 
Cc: Max Filippov 
Cc: Michael Neuling 
Cc: Michal Simek 
Cc: Mikael Starvik 
Cc: Nicolas Pitre 
Cc: Paolo Bonzini 
Cc: Paul Burton 
Cc: Paul E. McKenney 
Cc: Paul Gortmaker 
Cc: Paul Mackerras 
Cc: Qais Yousef 
Cc: Qiaowei Ren 
Cc: Rafael Wysocki 
Cc: Ralf Baechle 
Cc: Richard Henderson 
Cc: Richard Kuo 
Cc: Russell King 
Cc: Steven Miao 
Cc: Steven Rostedt 
Cc: Stratos Karafotis 
Cc: Tim Chen 
Cc: Tony Luck 
Cc: Vasily Kulikov 
Cc: Vineet Gupta 
Cc: Vineet Gupta 
Cc: Waiman Long 
Cc: Will Deacon 
Cc: Wolfram Sang 
Cc: adi-buildroot-devel@lists.sourceforge.net
Cc: linux390@de.ibm.com
Cc: linux-alpha@vger.kernel.org
Cc: linux-am33-list@redhat.com
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-c6x-dev@linux-c6x.org
Cc: linux-cris-kernel@axis.com
Cc: linux-hexagon@vger.kernel.org
Cc: linux-ia64@vger.kernel.org
Cc: linux@lists.openrisc.net
Cc: linux-m32r-ja@ml.linux-m32r.org
Cc: linux-m32r@ml.linux-m32r.org
Cc: linux-m68k@lists.linux-m68k.org
Cc: linux-metag@vger.kernel.org
Cc: linux-mips@linux-mips.org
Cc: linux-parisc@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-s390@vger.kernel.org
Cc: linux-sh@vger.kernel.org
Cc: linux-xtensa@linux-xtensa.org
Cc: sparclinux@vger.kernel.org
Link: http://lkml.kernel.org/r/1404079773.2619.4.camel@buesod1.americas.hpqcorp.net
Signed-off-by: Ingo Molnar

s390: split TIF bits into CIF, PIF and TIF bits

2014-05-20T06:58:47+00:00

The oi and ni instructions used in entry[64].S to set and clear bits
in the thread-flags are not guaranteed to be atomic in regard to other
CPUs. Split the TIF bits into CPU, pt_regs and thread-info specific
bits. Updates on the TIF bits are done with atomic instructions,
updates on CPU and pt_regs bits are done with non-atomic instructions.

Signed-off-by: Martin Schwidefsky

KVM: s390: Add FAULT_FLAG_RETRY_NOWAIT for guest fault

2014-01-30T11:50:39+00:00

In the case of a fault, we will retry to exit sie64 but with gmap fault
indication for this thread set. This makes it possible to handle async
page faults.

Based on a patch from Martin Schwidefsky.

Signed-off-by: Dominik Dingel 
Signed-off-by: Christian Borntraeger

s390/mm,tlb: correct tlb flush on page table upgrade

2013-11-04T12:51:47+00:00

The IDTE instruction used to flush TLB entries for a specific address
space uses the address-space-control element (ASCE) to identify
affected TLB entries. The upgrade of a page table adds a new top
level page table which changes the ASCE. The TLB entries associated
with the old ASCE need to be flushed and the ASCE for the address space
needs to be replaced synchronously on all CPUs which currently use it.
The concept of a lazy ASCE update with an exception handler is broken.

Signed-off-by: Martin Schwidefsky