linux-stable.git/arch/microblaze/mm, branch linux-4.2.y

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

sched/preempt, mm/kmap: Explicitly disable/enable preemption in kmap_atomic_*

2015-05-19T06:39:14+00:00

The existing code relies on pagefault_disable() implicitly disabling
preemption, so that no schedule will happen between kmap_atomic() and
kunmap_atomic().

Let's make this explicit, to prepare for pagefault_disable() not
touching preemption anymore.

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/1431359540-32227-5-git-send-email-dahi@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar

vm: add VM_FAULT_SIGSEGV handling support

2015-01-29T18:51:32+00:00

The core VM already knows about VM_FAULT_SIGBUS, but cannot return a
"you should SIGSEGV" error, because the SIGSEGV case was generally
handled by the caller - usually the architecture fault handler.

That results in lots of duplication - all the architecture fault
handlers end up doing very similar "look up vma, check permissions, do
retries etc" - but it generally works.  However, there are cases where
the VM actually wants to SIGSEGV, and applications _expect_ SIGSEGV.

In particular, when accessing the stack guard page, libsigsegv expects a
SIGSEGV.  And it usually got one, because the stack growth is handled by
that duplicated architecture fault handler.

However, when the generic VM layer started propagating the error return
from the stack expansion in commit fee7e49d4514 ("mm: propagate error
from stack expansion even for guard page"), that now exposed the
existing VM_FAULT_SIGBUS result to user space.  And user space really
expected SIGSEGV, not SIGBUS.

To fix that case, we need to add a VM_FAULT_SIGSEGV, and teach all those
duplicate architecture fault handlers about it.  They all already have
the code to handle SIGSEGV, so it's about just tying that new return
value to the existing code, but it's all a bit annoying.

This is the mindless minimal patch to do this.  A more extensive patch
would be to try to gather up the mostly shared fault handling logic into
one generic helper routine, and long-term we really should do that
cleanup.

Just from this patch, you can generally see that most architectures just
copied (directly or indirectly) the old x86 way of doing things, but in
the meantime that original x86 model has been improved to hold the VM
semaphore for shorter times etc and to handle VM_FAULT_RETRY and other
"newer" things, so it would be a good idea to bring all those
improvements to the generic case and teach other architectures about
them too.

Reported-and-tested-by: Takashi Iwai 
Tested-by: Jan Engelhardt 
Acked-by: Heiko Carstens  # "s390 still compiles and boots"
Cc: linux-arch@vger.kernel.org
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds

microblaze: Fix mmap for cache coherent memory

2014-12-17T11:59:59+00:00

When running in non-cache coherent configuration the memory that was
allocated with dma_alloc_coherent() has a custom mapping and so there is no
1-to-1 relationship between the kernel virtual address and the PFN. This
means that virt_to_pfn() will not work correctly for those addresses and the
default mmap implementation in the form of dma_common_mmap() will map some
random, but not the requested, memory area.

Fix this by providing a custom mmap implementation that looks up the PFN
from the page table rather than using virt_to_pfn.

Signed-off-by: Lars-Peter Clausen 
Signed-off-by: Michal Simek

microblaze: Use asm-generic/io.h

2014-04-07T12:25:53+00:00

Using generic io.h will narrow down code duplication
in architecture io.h.

- define PCI_IOBASE
- remove non existing pci_io_base extern

Signed-off-by: Michal Simek

memblock: make memblock_set_node() support different memblock_type

2014-01-22T00:19:44+00:00

[sfr@canb.auug.org.au: fix powerpc build]
Signed-off-by: Tang Chen 
Reviewed-by: Zhang Yanfei 
Cc: "H. Peter Anvin" 
Cc: "Rafael J . Wysocki" 
Cc: Chen Tang 
Cc: Gong Chen 
Cc: Ingo Molnar 
Cc: Jiang Liu 
Cc: Johannes Weiner 
Cc: Lai Jiangshan 
Cc: Larry Woodman 
Cc: Len Brown 
Cc: Liu Jiang 
Cc: Mel Gorman 
Cc: Michal Nazarewicz 
Cc: Minchan Kim 
Cc: Prarit Bhargava 
Cc: Rik van Riel 
Cc: Taku Izumi 
Cc: Tejun Heo 
Cc: Thomas Gleixner 
Cc: Thomas Renninger 
Cc: Toshi Kani 
Cc: Vasilis Liaskovitis 
Cc: Wanpeng Li 
Cc: Wen Congyang 
Cc: Yasuaki Ishimatsu 
Cc: Yinghai Lu 
Signed-off-by: Stephen Rothwell 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/arch: use __free_reserved_page() to simplify the code

2013-11-13T03:09:03+00:00

Use __free_reserved_page() to simplify the code in arch.

It used split_page() in consistent_alloc()/__dma_alloc_coherent()/dma_alloc_coherent(),
so page->_count == 1, and we can free it safely.

__free_reserved_page()
	ClearPageReserved()
	init_page_count()  // it won't change the value
	__free_page()

Signed-off-by: Xishi Qiu 
Cc: James Hogan 
Cc: Michal Simek 
Cc: Benjamin Herrenschmidt 
Cc: Paul Mackerras 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

arch: mm: pass userspace fault flag to generic fault handler

2013-09-12T22:38:01+00:00

Unlike global OOM handling, memory cgroup code will invoke the OOM killer
in any OOM situation because it has no way of telling faults occuring in
kernel context - which could be handled more gracefully - from
user-triggered faults.

Pass a flag that identifies faults originating in user space from the
architecture-specific fault handlers to generic code so that memcg OOM
handling can be improved.

Signed-off-by: Johannes Weiner 
Reviewed-by: Michal Hocko 
Cc: David Rientjes 
Cc: KAMEZAWA Hiroyuki 
Cc: azurIt 
Cc: KOSAKI Motohiro 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/microblaze: prepare for removing num_physpages and simplify mem_init()

2013-07-03T23:07:36+00:00

Prepare for removing num_physpages and simplify mem_init().

Signed-off-by: Jiang Liu 
Cc: Michal Simek 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: concentrate modification of totalram_pages into the mm core

2013-07-03T23:07:33+00:00

Concentrate code to modify totalram_pages into the mm core, so the arch
memory initialized code doesn't need to take care of it.  With these
changes applied, only following functions from mm core modify global
variable totalram_pages: free_bootmem_late(), free_all_bootmem(),
free_all_bootmem_node(), adjust_managed_page_count().

With this patch applied, it will be much more easier for us to keep
totalram_pages and zone->managed_pages in consistence.

Signed-off-by: Jiang Liu 
Acked-by: David Howells 
Cc: "H. Peter Anvin" 
Cc: "Michael S. Tsirkin" 
Cc: 
Cc: Arnd Bergmann 
Cc: Catalin Marinas 
Cc: Chris Metcalf 
Cc: Geert Uytterhoeven 
Cc: Ingo Molnar 
Cc: Jeremy Fitzhardinge 
Cc: Jianguo Wu 
Cc: Joonsoo Kim 
Cc: Kamezawa Hiroyuki 
Cc: Konrad Rzeszutek Wilk 
Cc: Marek Szyprowski 
Cc: Mel Gorman 
Cc: Michel Lespinasse 
Cc: Minchan Kim 
Cc: Rik van Riel 
Cc: Rusty Russell 
Cc: Tang Chen 
Cc: Tejun Heo 
Cc: Thomas Gleixner 
Cc: Wen Congyang 
Cc: Will Deacon 
Cc: Yasuaki Ishimatsu 
Cc: Yinghai Lu 
Cc: Russell King 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds