32bit and 64bit on x86 are tested and working.  The rest I have looked
at closely and I can't find any problems.

setns is an easy system call to wire up.  It just takes two ints so I
don't expect any weird architecture porting problems.

While doing this I have noticed that we have some architectures that are
very slow to get new system calls.  cris seems to be the slowest where
the last system calls wired up were preadv and pwritev.  avr32 is weird
in that recvmmsg was wired up but never declared in unistd.h.  frv is
behind with perf_event_open being the last syscall wired up.  On h8300
the last system call wired up was epoll_wait.  On m32r the last system
call wired up was fallocate.  mn10300 has recvmmsg as the last system
call wired up.  The rest seem to at least have syncfs wired up which was
new in the 2.6.39.

v2: Most of the architecture support added by Daniel Lezcano <dlezcano@fr.ibm.com>
v3: ported to v2.6.36-rc4 by: Eric W. Biederman <ebiederm@xmission.com>
v4: Moved wiring up of the system call to another patch
v5: ported to v2.6.39-rc6
v6: rebased onto parisc-next and net-next to avoid syscall  conflicts.
v7: ported to Linus's latest post 2.6.39 tree.

>  arch/blackfin/include/asm/unistd.h     |    3 ++-
>  arch/blackfin/mach-common/entry.S      |    1 +
Acked-by: NMike Frysinger <vapier@gentoo.org>

Oh - ia64 wiring looks good.
Acked-by: NTony Luck <tony.luck@intel.com>
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The previous style change enables to use asm-generic/bitops/le.h on s390.
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Greg Ungerer <gerg@uclinux.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The style that we normally use in asm-generic is to test the macro itself
for existence, so in asm-generic, do:

	#ifndef find_next_zero_bit_le
	extern unsigned long find_next_zero_bit_le(const void *addr,
		unsigned long size, unsigned long offset);
	#endif

and in the architectures, write

	static inline unsigned long find_next_zero_bit_le(const void *addr,
		unsigned long size, unsigned long offset)
	#define find_next_zero_bit_le find_next_zero_bit_le

This adds the #define for each of the optimized find bitops in the
architectures.
Suggested-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Acked-by: NHans-Christian Egtvedt <hans-christian.egtvedt@atmel.com>
Acked-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Acked-by: NGreg Ungerer <gerg@uclinux.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add ZONE_DMA to 31-bit config again. The performance gain is minimal
and hardly anybody cares anymore about a 31-bit kernel.
So add ZONE_DMA again to help with SLAB_CACHE_DMA removal for
!CONFIG_ZONE_DMA configurations.
Acked-by: NDavid Rientjes <rientjes@google.com>
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>

s390 arch backend for d065bd81 "mm: retry page fault when blocking on
disk transfer".
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>

If e.g. copy_from_user() generates a page fault and the kernel runs
into an OOM situation the system might lock up.
If the OOM killer sends a SIG_KILL to the current process it can't
handle it since it is stuck in a copy_from_user() - page fault loop.

Fix this by adding the same fix as other architectures have.

E.g. the x86 variant f86268 "x86/mm: Handle mm_fault_error() in kernel
space"
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>

Implement ndelay() on s390 as well.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Both functions take an int instead of an unsigned int. Fixes these
compile warnings:

kernel/sched.c:7167:2: warning: initialization from incompatible pointer type
kernel/sched.c:7170:2: warning: initialization from incompatible pointer type
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

The hardware sample cpu hotplug notifier always returns NOTIFY_BAD.
That will prevent cpu hotplug if the machine is enabled for hardware
sampling even if it is not used. Fix the cpu hotplug notifier and
allow cpu hotplug if hardware sampling is unused.
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>

Turn __access_ok() into a define and add a __chk_user_ptr() call
instead.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Merge irq.c and s390_ext.c into irq.c. That way all external interrupt
related functions are together.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Interrupt sources like pfault, sclp, dasd_diag and virtio all use the
service signal external interrupt subclass mask in control register 0
to enable and disable the corresponding interrupt.
Because no reference counting is implemented each subsystem thinks it
is the only user of subclass and sets and clears the bit like it wants.
This leads to case that unloading the dasd diag module under z/VM
causes both sclp and pfault interrupts to be masked. The result will
be locked up system sooner or later.
Fix this by introducing a new way to set (register) and clear
(unregister) the service signal subclass mask bit in cr0.
Also convert all drivers.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Always enable the service signal subclass mask bit in cr0, if pfault
is available. That way we use the normal cpu hotplug way to propagate
the subclass mask bit in cr0 instead of open coding it.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Fold all the mmu_gather rework patches into one for submission
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Reported-by: NHugh Dickins <hughd@google.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Miller <davem@davemloft.net>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Tony Luck <tony.luck@intel.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Adapt the stand-alone s390 mmu_gather implementation to the new
preemptible mmu_gather interface.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Miller <davem@davemloft.net>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Tony Luck <tony.luck@intel.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

All architectures supporting hibernation define
arch_prepare_suspend() as an empty function, so remove it.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

When disabling a cpu all external interrupt subclass masks in control
register 0 get cleared. However instead of the service signal subclass
mask bit an unused bit got cleared.
Accidently (or luckily) the service subclass mask gets cleared with the
pfault_fini() call that happens just before the rest of the subclass
mask bits get cleared.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>

The external interrupt parameter is passed as function call parameter.
No need to access lowcore.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>

Count CPU measurement external interrupts as well.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>

sendmmsg is reachable via the socket system call. We don't enable a second
way on s390 to reach the same system call.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Use ctl_set_bit instead of the smp_ctl_set_bit (likewise for clear bit)
to prevent the following build error for !CONFIG_SMP:

  CC      arch/s390/oprofile/hwsampler.o
arch/s390/oprofile/hwsampler.c: In function ‘hwsampler_deallocate’:
arch/s390/oprofile/hwsampler.c:1012: error: implicit declaration of function ‘smp_ctl_clear_bit’
arch/s390/oprofile/hwsampler.c: In function ‘hwsampler_start_all’:
arch/s390/oprofile/hwsampler.c:1201: error: implicit declaration of function ‘smp_ctl_set_bit’
  CC      kernel/seccomp.o
make[1]: *** [arch/s390/oprofile/hwsampler.o] Error 1
make: *** [arch/s390/oprofile] Error 2
Signed-off-by: NJan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

The counter for requested interrupts should be incremented if the
program-request-alert bit is set and not the invalid-address-entry
bit.
Signed-off-by: NJan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Remove unsused includes from arch/s390/kernel/process.c.
Signed-off-by: NJan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Rework the architecture page table functions to access the bits in the
page table extension array (pgste). There are a number of changes:
1) Fix missing pgste update if the attach_count for the mm is <= 1.
2) For every operation that affects the invalid bit in the pte or the
   rcp byte in the pgste the pcl lock needs to be acquired. The function
   pgste_get_lock gets the pcl lock and returns the current pgste value
   for a pte pointer. The function pgste_set_unlock stores the pgste
   and releases the lock. Between these two calls the bits in the pgste
   can be shuffled.
3) Define two software bits in the pte _PAGE_SWR and _PAGE_SWC to avoid
   calling SetPageDirty and SetPageReferenced from pgtable.h. If the
   host reference backup bit or the host change backup bit has been
   set the dirty/referenced state is transfered to the pte. The common
   code will pick up the state from the pte.
4) Add ptep_modify_prot_start and ptep_modify_prot_commit for mprotect.
5) Remove pgd_populate_kernel, pud_populate_kernel, pmd_populate_kernel
   pgd_clear_kernel, pud_clear_kernel, pmd_clear_kernel and ptep_invalidate.
6) Rename kvm_s390_test_and_clear_page_dirty to
   ptep_test_and_clear_user_dirty and add ptep_test_and_clear_user_young.
7) Define mm_exclusive() and mm_has_pgste() helper to improve readability.
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

The page_clear_dirty primitive always sets the default storage key
which resets the access control bits and the fetch protection bit.
That will surprise a KVM guest that sets non-zero access control
bits or the fetch protection bit. Merge page_test_dirty and
page_clear_dirty back to a single function and only clear the
dirty bit from the storage key.

In addition move the function page_test_and_clear_dirty and
page_test_and_clear_young to page.h where they belong. This
requires to change the parameter from a struct page * to a page
frame number.
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Adapt new API.
Signed-off-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

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

On cpu hot remove a PFAULT CANCEL command is sent to the hypervisor
which in turn will cancel all outstanding pfault requests that have
been issued on that cpu (the same happens with a SIGP cpu reset).

The result is that we end up with uninterruptible processes where
the interrupt that would wake up these processes never arrives.

In order to solve this all processes which wait for a pfault
completion interrupt get woken up after a cpu hot remove. The worst
case that could happen is that they fault again and in turn need to
wait again.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Add missing __noreturn attribute to cpu_die():

arch/s390/kernel/smp.c:691:6: error: symbol 'cpu_die' redeclared with different type
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Implement arch specific irqsafe_cpu ops. The arch specific ops do not
disable/enable interrupts since that is an expensive operation. Instead
we disable preemption and perform a compare and swap loop.
Since on server distros (the ones we care about) preemption is disabled
the preempt_disable()/preempt_enable() pair is a nop.
In the end this code should be faster than the generic one.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

The concepts of VDSO and gcov-based profiling don't mix: the former
includes kernel-provided code running in userspace, the latter adds
instructions that modify counters in kernel data segments. On s390
this has not been a problem so far due to VDSO code being written in
all-assembler which is exempt from gcov-based profiling. This could
change in the future, so disable profiling excplicitly for VDSO code.
Signed-off-by: NPeter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Get rid of these:

arch/s390/mm/extmem.c: In function 'segment_modify_shared':
arch/s390/mm/extmem.c:622:3: warning: 'end_addr' may be used uninitialized in this function [-Wuninitialized]
arch/s390/mm/extmem.c:627:18: warning: 'start_addr' may be used uninitialized in this function [-Wuninitialized]
arch/s390/mm/extmem.c: In function 'segment_load':
arch/s390/mm/extmem.c:481:11: warning: 'end_addr' may be used uninitialized in this function [-Wuninitialized]
arch/s390/mm/extmem.c:480:18: warning: 'start_addr' may be used uninitialized in this function [-Wuninitialized]
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Remove trivially unused variables as detected with -Wunused-but-set-variable.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

The noexec support on s390 does not rely on a bit in the page table
entry but utilizes the secondary space mode to distinguish between
memory accesses for instructions vs. data. The noexec code relies
on the assumption that the cpu will always use the secondary space
page table for data accesses while it is running in the secondary
space mode. Up to the z9-109 class machines this has been the case.
Unfortunately this is not true anymore with z10 and later machines.
The load-relative-long instructions lrl, lgrl and lgfrl access the
memory operand using the same addressing-space mode that has been
used to fetch the instruction.
This breaks the noexec mode for all user space binaries compiled
with march=z10 or later. The only option is to remove the current
noexec support.
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

While debugging I stumbled over two problems in the code that protects module
pages.

First issue is that disabling the protection before freeing init or unload of
a module is not symmetric with the enablement. For instance, if pages are set
to RO the page range from module_core to module_core + core_ro_size is
protected. If a module is unloaded the page range from module_core to
module_core + core_size is set back to RW.
So pages that were not set to RO are also changed to RW.
This is not critical but IMHO it should be symmetric.

Second issue is that while set_memory_rw & set_memory_ro are used for
RO/RW changes only set_memory_nx is involved for NX/X. One would await that
the inverse function is called when the NX protection should be removed,
which is not the case here, unless I'm missing something.
Signed-off-by: NJan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Do the mcount offset adjustment in the recordmcount.pl/recordmcount.[ch]
at compile time and not in ftrace_call_adjust at run time.
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

Processes started with kernel_execve from a kernel thread will have
current->mm==NULL. Reading current->mm->context.alloc_pgste will
read a more or less random bit from lowcore in this case. If the
bit turns out to be set the whole process tree started this way
will allocate page table extensions although they have no need
for it.
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

oprofile_min_interval and oprofile_max_interval are unsigned, checking
for negative values doesn't work. Change hwsampler_query_min_interval
and hwsampler_query_max_interval to return an unsigned long and
check for a zero value instead.
Reported-by: NNicolas Kaiser <nikai@nikai.net>
Acked-by: NRobert Richter <robert.richter@amd.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Currently the diag10() function can only release one page. For exploiters
that have to call diag10 on a contiguous memory region this is suboptimal.
This patch replaces the diag10() function with diag10_range() that is
able to release multiple pages. In addition to that the new function now
allows to release memory with addresses higher than 2047 MiB. This was
due to a restriction of the diagnose implementation under z/VM prior to
release 5.2.
Signed-off-by: NMichael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/kvm/sie64a.S uses the b280 instruction. Tell the builtin
disassembler to handle that code.
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>