linux-toradex.git/arch/s390/mm, branch v4.2.4

revert "s390/mm: make hugepages_supported a boot time decision"

2015-07-17T23:39:52+00:00

Heiko noticed that the current check for hugepage support on s390 is a
little bit too harsh as systems which do not support will crash.

The reason is that pageblock_order can now get negative when we set
HPAGE_SHIFT to 0.  To avoid all this and to avoid opening another can of
worms with enabling HUGETLB_PAGE_SIZE_VARIABLE I think it would be best
to simply allow architectures to define their own hugepages_supported().

Revert bea41197ead3 ("s390/mm: make hugepages_supported a boot time
decision") in preparation.

Signed-off-by: Dominik Dingel 
Acked-by: Martin Schwidefsky 
Cc: Heiko Carstens 
Cc: Christian Borntraeger 
Cc: Michael Holzheu 
Cc: Gerald Schaefer 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

revert "s390/mm: change HPAGE_SHIFT type to int"

2015-07-17T23:39:52+00:00

Heiko noticed that the current check for hugepage support on s390 is a
little bit too harsh as systems which do not support will crash.

The reason is that pageblock_order can now get negative when we set
HPAGE_SHIFT to 0.  To avoid all this and to avoid opening another can of
worms with enabling HUGETLB_PAGE_SIZE_VARIABLE I think it would be best
to simply allow architectures to define their own hugepages_supported().

This patch (of 4): revert commit cf54e2fce51c ("s390/mm: change
HPAGE_SHIFT type to int") in preparation.

Signed-off-by: Dominik Dingel 
Acked-by: Martin Schwidefsky 
Cc: Heiko Carstens 
Cc: Christian Borntraeger 
Cc: Michael Holzheu 
Cc: Gerald Schaefer 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

s390/mm: change HPAGE_SHIFT type to int

2015-06-26T00:00:35+00:00

With making HPAGE_SHIFT an unsigned integer we also accidentally changed
pageblock_order.  In order to avoid compiler warnings we make
HPAGE_SHFIT an int again.

Signed-off-by: Dominik Dingel 
Suggested-by: Andrew Morton 
Cc: Martin Schwidefsky 
Cc: Heiko Carstens 
Cc: Christian Borntraeger 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

s390/mm: forward check for huge pmds to pmd_large()

2015-06-26T00:00:35+00:00

We already do the check in pmd_large, so we can just forward the call.

Signed-off-by: Dominik Dingel 
Acked-by: Martin Schwidefsky 
Cc: Heiko Carstens 
Cc: Christian Borntraeger 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

s390/hugetlb: remove dead code for sw emulated huge pages

2015-06-26T00:00:35+00:00

We now support only hugepages on hardware with EDAT1 support.  So we
remove the prepare/release_hugepage hooks and simplify set_huge_pte_at
and huge_ptep_get.

Signed-off-by: Dominik Dingel 
Acked-by: Martin Schwidefsky 
Cc: Heiko Carstens 
Cc: Christian Borntraeger 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

s390/mm: make hugepages_supported a boot time decision

2015-06-26T00:00:35+00:00

There is a potential bug with KVM and hugetlbfs if the hardware does not
support hugepages (EDAT1).  We fix this by making EDAT1 a hard requirement
for hugepages and therefore removing and simplifying code.

As s390, with the sw-emulated hugepages, was the only user of
arch_prepare/release_hugepage I also removed theses calls from common and
other architecture code.

This patch (of 5):

By dropping support for hugepages on machines which do not have the
hardware feature EDAT1, we fix a potential s390 KVM bug.

The bug would happen if a guest is backed by hugetlbfs (not supported
currently), but does not get pagetables with PGSTE.  This would lead to
random memory overwrites.

Signed-off-by: Dominik Dingel 
Acked-by: Martin Schwidefsky 
Cc: Heiko Carstens 
Cc: Christian Borntraeger 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/hugetlb: reduce arch dependent code about huge_pmd_unshare

2015-06-25T00:49:41+00:00

Currently we have many duplicates in definitions of huge_pmd_unshare.  In
all architectures this function just returns 0 when
CONFIG_ARCH_WANT_HUGE_PMD_SHARE is N.

This patch puts the default implementation in mm/hugetlb.c and lets these
architectures use the common code.

Signed-off-by: Zhang Zhen 
Cc: Russell King 
Cc: Catalin Marinas 
Cc: Tony Luck 
Cc: James Hogan 
Cc: Ralf Baechle 
Cc: Benjamin Herrenschmidt 
Cc: Martin Schwidefsky 
Cc: Chris Metcalf 
Cc: David Rientjes 
Cc: James Yang 
Cc: Aneesh Kumar 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

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

2015-06-24T15:45:27+00:00

Pull s390 updates from Martin Schwidefsky:
 "Pretty boring for a merge window pull.

  One change in behaviour is the patch for dasd driver, the module which
  provides the diagnose discipline is now loaded automatically.

  The SCLP code got a nice cleanup, a new global structure replaces a
  bunch of accessor functions.

  And a couple of random, small improvements"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
  s390/pci: improve handling of hotplug event 0x301
  s390/setup: fix DMA_API_DEBUG warnings
  s390/zcrypt: remove obsolete __constant
  s390/keyboard: avoid off-by-one when using strnlen_user()
  s390/sclp: pass timeout as HZ independent value
  s390/mm: s/specifiation/specification/, s/an specification/a specification/
  s390/sclp: Use DECLARE_BITMAP
  s390/dasd: Enable automatic loading of dasd_diag_mod
  s390/sclp: move sclp_facilities into "struct sclp"
  s390/sclp: get rid of sclp_get_mtid() and sclp_get_mtid_max()
  s390/sclp: unify basic sclp access by exposing "struct sclp"
  s390/sclp: prepare smp_fill_possible_mask for global "struct sclp"

mm/fault, arch: Use pagefault_disable() to check for disabled pagefaults in the handler

2015-05-19T06:39:15+00:00

Introduce faulthandler_disabled() and use it to check for irq context and
disabled pagefaults (via pagefault_disable()) in the pagefault handlers.

Please note that we keep the in_atomic() checks in place - to detect
whether in irq context (in which case preemption is always properly
disabled).

In contrast, preempt_disable() should never be used to disable pagefaults.
With !CONFIG_PREEMPT_COUNT, preempt_disable() doesn't modify the preempt
counter, and therefore the result of in_atomic() differs.
We validate that condition by using might_fault() checks when calling
might_sleep().

Therefore, add a comment to faulthandler_disabled(), describing why this
is needed.

faulthandler_disabled() and pagefault_disable() are defined in
linux/uaccess.h, so let's properly add that include to all relevant files.

This patch is based on a patch from Thomas Gleixner.

Reviewed-and-tested-by: Thomas Gleixner 
Signed-off-by: David Hildenbrand 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: David.Laight@ACULAB.COM
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: airlied@linux.ie
Cc: akpm@linux-foundation.org
Cc: benh@kernel.crashing.org
Cc: bigeasy@linutronix.de
Cc: borntraeger@de.ibm.com
Cc: daniel.vetter@intel.com
Cc: heiko.carstens@de.ibm.com
Cc: herbert@gondor.apana.org.au
Cc: hocko@suse.cz
Cc: hughd@google.com
Cc: mst@redhat.com
Cc: paulus@samba.org
Cc: ralf@linux-mips.org
Cc: schwidefsky@de.ibm.com
Cc: yang.shi@windriver.com
Link: http://lkml.kernel.org/r/1431359540-32227-7-git-send-email-dahi@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar

s390/sclp: unify basic sclp access by exposing "struct sclp"

2015-05-13T07:58:17+00:00

Let's unify basic access to sclp fields by storing the data in an external
struct in asm/sclp.h.

The values can now directly be accessed by other components, so there is
no need for most accessor functions and external variables anymore.

The mtid, mtid_max and facility part will be cleaned up separately.

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