Analog to git commit 0c8c0f03
"x86/fpu, sched: Dynamically allocate 'struct fpu'"
move the struct fpu to the end of the struct thread_struct,
set CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT and add the
setup_task_size() function to calculate the correct size
fo the task struct.

For the performance_defconfig this increases the size of
struct task_struct from 7424 bytes to 7936 bytes (MACHINE_HAS_VX==1)
or 7552 bytes (MACHINE_HAS_VX==0). The dynamic allocation of the
struct fpu is removed. The slab cache uses an 8KB block for the
task struct in all cases, there is enough room for the struct fpu.
For MACHINE_HAS_VX==1 each task now needs 512 bytes less memory.
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

KASAN needs to know whether the allocation happens in an IRQ handler.
This lets us strip everything below the IRQ entry point to reduce the
number of unique stack traces needed to be stored.

Move the definition of __irq_entry to <linux/interrupt.h> so that the
users don't need to pull in <linux/ftrace.h>.  Also introduce the
__softirq_entry macro which is similar to __irq_entry, but puts the
corresponding functions to the .softirqentry.text section.
Signed-off-by: NAlexander Potapenko <glider@google.com>
Acked-by: NSteven Rostedt <rostedt@goodmis.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Andrey Konovalov <adech.fo@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Konstantin Serebryany <kcc@google.com>
Cc: Dmitry Chernenkov <dmitryc@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This changes several users of manual "on"/"off" parsing to use
strtobool.

Some side-effects:
- these uses will now parse y/n/1/0 meaningfully too
- the early_param uses will now bubble up parse errors
Signed-off-by: NKees Cook <keescook@chromium.org>
Acked-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: NMichael Ellerman <mpe@ellerman.id.au>
Cc: Amitkumar Karwar <akarwar@marvell.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Joe Perches <joe@perches.com>
Cc: Kalle Valo <kvalo@codeaurora.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Nishant Sarmukadam <nishants@marvell.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Steve French <sfrench@samba.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The cpumf_pmu_notfier() hotplug callback lacks handling of the
CPU_DOWN_FAILED case. That means, if CPU_DOWN_PREPARE failes, the PMC
of the CPU is not setup again. Furthermore the CPU_ONLINE_FROZEN case
will never be processed because of masking the switch expression with
CPU_TASKS_FROZEN.

Add handling for CPU_DOWN_FAILED transition to setup the PMC of the
CPU. Remove CPU_ONLINE_FROZEN case.
Signed-off-by: NAnna-Maria Gleixner <anna-maria@linutronix.de>
Acked-by: NHendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

The cpumf_pmu_notfier() hotplug callback lacks handling of the
CPU_DOWN_FAILED case. That means, if CPU_DOWN_PREPARE failes, the PMC
of the CPU is not setup again.

Add handling for CPU_DOWN_FAILED transition to setup the PMC of the
CPU.
Signed-off-by: NAnna-Maria Gleixner <anna-maria@linutronix.de>
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

We can use debug_pagealloc_enabled() to check if we can map the identity
mapping with 1MB/2GB pages as well as to print the current setting in
dump_stack.
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Acked-by: NDavid Rientjes <rientjes@google.com>
Cc: Laura Abbott <labbott@fedoraproject.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There is a tricky interaction between the machine check handler
and the critical sections of load_fpu_regs and save_fpu_regs
functions. If the machine check interrupts one of the two
functions the critical section cleanup will complete the function
before the machine check handler s390_do_machine_check is called.
Trouble is that the machine check handler needs to validate the
floating point registers *before* and not *after* the completion
of load_fpu_regs/save_fpu_regs.

The simplest solution is to rewind the PSW to the start of the
load_fpu_regs/save_fpu_regs and retry the function after the
return from the machine check handler.
Tested-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Cc: <stable@vger.kernel.org> # 4.3+
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Add the missing lpp magic initialization for cpu 0. Without this all
samples on cpu 0 do not have the most significant bit set in the
program parameter field, which we use to distinguish between guest and
host samples if the pid is also 0.

We did initialize the lpp magic in the absolute zero lowcore but
forgot that when switching to the allocated lowcore on cpu 0 only.
Reported-by: NShu Juan Zhang <zhshuj@cn.ibm.com>
Acked-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Cc: stable@vger.kernel.org # v4.4+
Fixes: e22cf8ca ("s390/cpumf: rework program parameter setting to detect guest samples")
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Signed-off-by: NAdam Buchbinder <adam.buchbinder@gmail.com>
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

The pgtable.c file is quite big, before it grows any larger split it
into pgtable.c, pgalloc.c and gmap.c. In addition move the gmap related
header definitions into the new gmap.h header and all of the pgste
helpers from pgtable.h to pgtable.c.
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

we have to check bit 40 of the facility list before issuing LPP
and not bit 48. Otherwise a guest running on a system with
"The decimal-floating-point zoned-conversion facility" and without
the "The set-program-parameters facility" might crash on an lpp
instruction.
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Cc: stable@vger.kernel.org # v4.4+
Fixes: e22cf8ca ("s390/cpumf: rework program parameter setting to detect guest samples")
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Convert the uses of pr_warning to pr_warn so there are fewer
uses of the old pr_warning.

Miscellanea:

o Align arguments
o Coalesce formats
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

commit e22cf8ca ("s390/cpumf: rework program parameter setting
to detect guest samples") requires guest changes to get proper
guest/host. We can do better: We can use the primary asn value,
which is set on all Linux variants to compare this with the host
pp value.
We now have the following cases:
1. Guest using PP
host sample:  gpp == 0, asn == hpp --> host
guest sample: gpp != 0 --> guest
2. Guest not using PP
host sample:  gpp == 0, asn == hpp --> host
guest sample: gpp == 0, asn != hpp --> guest

As soon as the host no longer sets CR4, we must back out
this heuristics - let's add a comment in switch_to.
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: NHendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

We have two close to identical report_user_fault functions.
Add a parameter to one and get rid of the other one in order
to reduce code duplication.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

The double escape character sequence introduced with commit
272fa59c ("s390/dis: Fix handling of format specifiers") is not
necessary anymore since commit 561e1030 ("s390/dis: Fix printing
of the register numbers").

Instead this now generates an extra '%' character:

lg      %%r1,160(%%r11)

So fix this and basically revert 272fa59c.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Let the non boot cpus call into idle with the corresponding hotplug state, so
the hotplug core can handle the further bringup. That's a first step to
convert the boot side of the hotplugged cpus to do all the synchronization
with the other side through the state machine. For now it'll only start the
hotplug thread and kick the full bringup of the cpu.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org
Cc: Rik van Riel <riel@redhat.com>
Cc: Rafael Wysocki <rafael.j.wysocki@intel.com>
Cc: "Srivatsa S. Bhat" <srivatsa@mit.edu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Turner <pjt@google.com>
Link: http://lkml.kernel.org/r/20160226182341.614102639@linutronix.deSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

We have four different stack tracers of which three had bugs. So it's
time to merge them to a single stack tracer which allows to specify a
call back function which will be called for each step.

This patch changes behavior a bit:

- the "nosched" and "in_sched_functions" check within
  save_stack_trace_tsk did work only for the last stack frame within a
  context. Now it considers the check for each stack frame like it
  should.

- both the oprofile variant and the perf_events variant did save a
  return address twice if a zero back chain was detected, which
  indicates an interrupt frame. The new dump_trace function will call
  the oprofile and perf_events backends with the psw address that is
  contained within the corresponding pt_regs structure instead.

- the original show_trace and save_context_stack functions did already
  use the psw address of the pt_regs structure if a zero back chain
  was detected. However now we ignore the psw address if it is a user
  space address. After all we trace the kernel stack and not the user
  space stack. This way we also get rid of the garbage user space
  address in case of warnings and / or panic call traces.

So this should make life easier since now there is only one stack
tracer left which we can break.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Implement current_stack_pointer() helper function and use it
everywhere, instead of having several different inline assembly
variants.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Tested-by: NPeter Oberparleiter <oberpar@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Use the inversed "nosched" logic like all other architectures.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Tested-by: NPeter Oberparleiter <oberpar@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

git commit 80703617
"s390: add support for vector extension"
broke 31-bit compat processes in regard to signal handling.

The restore_sigregs_ext32() function is used to restore the additional
elements from the user space signal frame. Among the additional elements
are the upper registers halves for 64-bit register support for 31-bit
processes. The copy_from_user that is used to retrieve the high-gprs
array from the user stack uses an incorrect length, 8 bytes instead of
64 bytes. This causes incorrect upper register halves to get loaded.

Cc: stable@vger.kernel.org # 3.8+
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

The diagnose tracer will indirectly call back into the lockdep code
when lockdep does not expect it (arch_spinlock). This causes lockdep
to disable itself and therefore we don't have a working lock
dependency validator anymore.

This patch effectively disables tracing of diag 0x9c and 0x44 if
lockdep is enabled.  If however lockdep is enabled spinlocks are
mainly implemented using a trylock variant, which will not issue any
diag 0x9c or 0x44. So this change has hardly any effect on tracing
except when arch_spinlock and friends are explicitly used.
Reported-and-Tested-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Acked-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

git commit dc7ee00d ("s390: lowcore stack pointer offsets")
introduced a regression in regard to perf_callchain_kernel(). The
stack pointer for the asynchronous stack in the lowcore now has an
additional offset applied. This offset needs to be taken into account
in the calculation for the low and high address for the stack.

This bug was already partially fixed with 9cc5c206
("s390/dumpstack: fix address ranges for asynchronous and panic
stack"). This patch fixes it also for the perf_event code.

Fixes: dc7ee00d ("s390: lowcore stack pointer offsets")
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Implement save_stack_trace_regs, so that a stack trace of a kprobe
event can be obtained.

Without this we see following warning:
"save_stack_trace_regs() not implemented yet."
when we execute:
echo stacktrace > /sys/kernel/debug/tracing/trace_options
echo "p kfree" >> /sys/kernel/debug/tracing/kprobe_events
echo 1 > /sys/kernel/debug/tracing/events/kprobes/enable
Reported-by: NChunyu Hu <chuhu@redhat.com>
Signed-off-by: NPratyush Anand <panand@redhat.com>
[heiko.carstens@de.ibm.com]: changed patch to use __save_stack_trace()
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Tested-by: NPeter Oberparleiter <oberpar@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

save_stack_trace() only saves the stack trace of the current context
(interrupt or process context). This is different to what other
architectures like x86 do, which save the full stack trace across
different contexts.

Also extract a __save_stack_trace() helper function which will be used
by a follow on patch.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Tested-by: NPeter Oberparleiter <oberpar@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

save_stack_trace() did not write the ULONG_MAX end marker if there is
enough space left. So simply follow x86 and arm64.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Tested-by: NPeter Oberparleiter <oberpar@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

git commit dc7ee00d ("s390: lowcore stack pointer offsets")
introduced a regression in regard to save_stack_trace(). The stack
pointer for the asynchronous and the panic stack in the lowcore now
have an additional offset applied to them. This offset needs to be
taken into account in the calculation for the low and high address for
the stacks.

This bug was already partially fixed with 9cc5c206
("s390/dumpstack: fix address ranges for asynchronous and panic
stack"). This patch fixes it also for the stacktrace code.

Fixes: dc7ee00d ("s390: lowcore stack pointer offsets")
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Tested-by: NPeter Oberparleiter <oberpar@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

The function save_stack_trace_tsk() did not consider that it can be
used for tsk == current, for which the current stack pointer obviously
cannot be found in the thread structure.

Fix this and get the stack pointer with an inline assembly.

This fixes e.g. the output of "cat /proc/self/stack".

Before:
[<0000000000000000>]           (null)
[<ffffffffffffffff>] 0xffffffffffffffff

After:
[<000000000011b3ee>] save_stack_trace_tsk+0x56/0x98
[<0000000000366cde>] proc_pid_stack+0xae/0x108
[<00000000003636f0>] proc_single_show+0x70/0xc0
[<0000000000311fbc>] seq_read+0xcc/0x448
[<00000000002e7716>] __vfs_read+0x36/0x100
[<00000000002e872e>] vfs_read+0x76/0x130
[<00000000002e975e>] SyS_read+0x66/0xd8
[<000000000089490e>] system_call+0xd6/0x264
[<ffffffffffffffff>] 0xffffffffffffffff
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Tested-by: NPeter Oberparleiter <oberpar@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Lockdep is initialized at compile time now.  Get rid of lockdep_init().
Signed-off-by: NAndrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Krinkin <krinkin.m.u@gmail.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Cc: mm-commits@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

Set IORESOURCE_SYSTEM_RAM in flags of resource ranges with
"System RAM", "Kernel code", "Kernel data", and "Kernel bss".

Note that:

 - IORESOURCE_SYSRAM (i.e. modifier bit) is set in flags when
   IORESOURCE_MEM is already set. IORESOURCE_SYSTEM_RAM is defined
   as (IORESOURCE_MEM|IORESOURCE_SYSRAM).

 - Some archs do not set 'flags' for children nodes, such as
   "Kernel code".  This patch does not change 'flags' in this
   case.
Signed-off-by: NToshi Kani <toshi.kani@hpe.com>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: linux-arch@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-mips@linux-mips.org
Cc: linux-mm <linux-mm@kvack.org>
Cc: linux-parisc@vger.kernel.org
Cc: linux-s390@vger.kernel.org
Cc: linux-sh@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: sparclinux@vger.kernel.org
Link: http://lkml.kernel.org/r/1453841853-11383-7-git-send-email-bp@alien8.deSigned-off-by: NIngo Molnar <mingo@kernel.org>

Yet another leftover from the 31 bit era. The usual operation
"y = x & PSW_ADDR_INSN" with the PSW_ADDR_INSN mask is a nop for
CONFIG_64BIT.

Therefore remove all usages and hope the code is a bit less confusing.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>

This is a leftover from the 31 bit area. For CONFIG_64BIT the usual
operation "y = x | PSW_ADDR_AMODE" is a nop. Therefore remove all
usages of PSW_ADDR_AMODE and make the code a bit less confusing.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>

Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

memblock_alloc() and memblock_alloc_base() will panic on their own if
they can't find free memory. Therefore remove some pointless checks.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: NMichael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Add the CPU number to the per-cpu vdso data page and add the
__kernel_getcpu function to the vdso object to retrieve the
CPU number in user space.
Suggested-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

The initial s390 vdso code is heavily influenced by the powerpc version
which does have a smp_wmb in vdso_init right before the vdso_ready=1
assignment. s390 has no need for that.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Message-Id: <1452010645-25380-1-git-send-email-mst@redhat.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Finally get rid of the leading underscore. I tried this already two or
three years ago, however Michael Holzheu objected since this would
break the crash utility (again).

However Michael integrated support for the new name into the crash
utility back then, so it doesn't break if the name will be changed
now.  So finally get rid of the ever confusing leading underscore.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>