Commit Graph

389 Commits

Author SHA1 Message Date
Paul Gortmaker cdd4f4c710 sparc: migrate exception table users off module.h and onto extable.h
These files were only including module.h for exception table
related functions.  We've now separated that content out into its
own file "extable.h" so now move over to that and avoid all the
extra header content in module.h that we don't really need to compile
these files.

Cc: "David S. Miller" <davem@davemloft.net>
Cc: sparclinux@vger.kernel.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-10-06 01:42:30 -04:00
Atish Patra ebb99a4c12 sparc64: Fix irq stack bootmem allocation.
Currently, irq stack bootmem is allocated for all possible cpus
before nr_cpus value changes the list of possible cpus. As a result,
there is unnecessary wastage of bootmemory.

Move the irq stack bootmem allocation so that it happens after
possible cpu list is modified based on nr_cpus value.

Signed-off-by: Atish Patra <atish.patra@oracle.com>
Reviewed-by: Bob Picco <bob.picco@oracle.com>
Reviewed-by: Vijay Kumar <vijay.ac.kumar@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-09-28 08:24:03 -07:00
Mike Kravetz 1e953d846a sparc64 mm: Fix more TSB sizing issues
Commit af1b1a9b36 ("sparc64 mm: Fix base TSB sizing when hugetlb
pages are used") addressed the difference between hugetlb and THP
pages when computing TSB sizes.  The following additional issues
were also discovered while working with the code.

In order to save memory, THP makes use of a huge zero page.  This huge
zero page does not count against a task's RSS, but it does consume TSB
entries.  This is similar to hugetlb pages.  Therefore, count huge
zero page entries in hugetlb_pte_count.

Accounting of THP pages is done in the routine set_pmd_at().
Unfortunately, this does not catch the case where a THP page is split.
To handle this case, decrement the count in pmdp_invalidate().
pmdp_invalidate is only called when splitting a THP.  However, 'sanity
checks' are added in case it is ever called for other purposes.

A more general issue exists with HPAGE_SIZE accounting.
hugetlb_pte_count tracks the number of HPAGE_SIZE (8M) pages.  This
value is used to size the TSB for HPAGE_SIZE pages.  However,
each HPAGE_SIZE page consists of two REAL_HPAGE_SIZE (4M) pages.
The TSB contains an entry for each REAL_HPAGE_SIZE page.  Therefore,
the number of REAL_HPAGE_SIZE pages should be used to size the huge
page TSB.  A new compile time constant REAL_HPAGE_PER_HPAGE is used
to multiply hugetlb_pte_count before sizing the TSB.

Changes from V1
- Fixed build issue if hugetlb or THP not configured

Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-09-28 08:24:02 -07:00
Paul Gortmaker bdf2f59e64 sparc64: fix section mismatch in find_numa_latencies_for_group
To fix:

  WARNING: vmlinux.o(.text.unlikely+0x580): Section mismatch in
  reference from the function find_numa_latencies_for_group() to the
  function .init.text:find_mlgroup()

  The function find_numa_latencies_for_group() references the
  function __init find_mlgroup().  This is often because
  find_numa_latencies_for_group lacks a __init annotation or the
  annotation of find_mlgroup is wrong.

It turns out find_numa_latencies_for_group is only called from:
    static int __init numa_parse_mdesc(void)
and hence we can tag find_numa_latencies_for_group with __init.

In doing so we see that find_best_numa_node_for_mlgroup is only
called from within __init and hence can also be marked with __init.

Cc: "David S. Miller" <davem@davemloft.net>
Cc: Nitin Gupta <nitin.m.gupta@oracle.com>
Cc: Chris Hyser <chris.hyser@oracle.com>
Cc: Santosh Shilimkar <santosh.shilimkar@oracle.com>
Cc: sparclinux@vger.kernel.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-09-28 08:24:02 -07:00
Nitin Gupta 7bc3777ca1 sparc64: Trim page tables for 8M hugepages
For PMD aligned (8M) hugepages, we currently allocate
all four page table levels which is wasteful. We now
allocate till PMD level only which saves memory usage
from page tables.

Also, when freeing page table for 8M hugepage backed region,
make sure we don't try to access non-existent PTE level.

Orabug: 22630259

Signed-off-by: Nitin Gupta <nitin.m.gupta@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-07-29 10:49:16 -07:00
Mike Kravetz af1b1a9b36 sparc64 mm: Fix base TSB sizing when hugetlb pages are used
do_sparc64_fault() calculates both the base and huge page RSS sizes and
uses this information in calls to tsb_grow().  The calculation for base
page TSB size is not correct if the task uses hugetlb pages.  hugetlb
pages are not accounted for in RSS, therefore the call to get_mm_rss(mm)
does not include hugetlb pages.  However, the number of pages based on
huge_pte_count (which does include hugetlb pages) is subtracted from
this value.  This will result in an artificially small and often negative
RSS calculation.  The base TSB size is then often set to max_tsb_size
as the passed RSS is unsigned, so a negative value looks really big.

THP pages are also accounted for in huge_pte_count, and THP pages are
accounted for in RSS so the calculation in do_sparc64_fault() is correct
if a task only uses THP pages.

A single huge_pte_count is not sufficient for TSB sizing if both hugetlb
and THP pages can be used.  Instead of a single counter, use two:  one
for hugetlb and one for THP.

Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-07-28 21:22:12 -07:00
Kirill A. Shutemov dcddffd41d mm: do not pass mm_struct into handle_mm_fault
We always have vma->vm_mm around.

Link: http://lkml.kernel.org/r/1466021202-61880-8-git-send-email-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-26 16:19:19 -07:00
Michal Hocko 32d6bd9059 tree wide: get rid of __GFP_REPEAT for order-0 allocations part I
This is the third version of the patchset previously sent [1].  I have
basically only rebased it on top of 4.7-rc1 tree and dropped "dm: get
rid of superfluous gfp flags" which went through dm tree.  I am sending
it now because it is tree wide and chances for conflicts are reduced
considerably when we want to target rc2.  I plan to send the next step
and rename the flag and move to a better semantic later during this
release cycle so we will have a new semantic ready for 4.8 merge window
hopefully.

Motivation:

While working on something unrelated I've checked the current usage of
__GFP_REPEAT in the tree.  It seems that a majority of the usage is and
always has been bogus because __GFP_REPEAT has always been about costly
high order allocations while we are using it for order-0 or very small
orders very often.  It seems that a big pile of them is just a
copy&paste when a code has been adopted from one arch to another.

I think it makes some sense to get rid of them because they are just
making the semantic more unclear.  Please note that GFP_REPEAT is
documented as

* __GFP_REPEAT: Try hard to allocate the memory, but the allocation attempt

* _might_ fail.  This depends upon the particular VM implementation.
  while !costly requests have basically nofail semantic.  So one could
  reasonably expect that order-0 request with __GFP_REPEAT will not loop
  for ever.  This is not implemented right now though.

I would like to move on with __GFP_REPEAT and define a better semantic
for it.

  $ git grep __GFP_REPEAT origin/master | wc -l
  111
  $ git grep __GFP_REPEAT | wc -l
  36

So we are down to the third after this patch series.  The remaining
places really seem to be relying on __GFP_REPEAT due to large allocation
requests.  This still needs some double checking which I will do later
after all the simple ones are sorted out.

I am touching a lot of arch specific code here and I hope I got it right
but as a matter of fact I even didn't compile test for some archs as I
do not have cross compiler for them.  Patches should be quite trivial to
review for stupid compile mistakes though.  The tricky parts are usually
hidden by macro definitions and thats where I would appreciate help from
arch maintainers.

[1] http://lkml.kernel.org/r/1461849846-27209-1-git-send-email-mhocko@kernel.org

This patch (of 19):

__GFP_REPEAT has a rather weak semantic but since it has been introduced
around 2.6.12 it has been ignored for low order allocations.  Yet we
have the full kernel tree with its usage for apparently order-0
allocations.  This is really confusing because __GFP_REPEAT is
explicitly documented to allow allocation failures which is a weaker
semantic than the current order-0 has (basically nofail).

Let's simply drop __GFP_REPEAT from those places.  This would allow to
identify place which really need allocator to retry harder and formulate
a more specific semantic for what the flag is supposed to do actually.

Link: http://lkml.kernel.org/r/1464599699-30131-2-git-send-email-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chen Liqin <liqin.linux@gmail.com>
Cc: Chris Metcalf <cmetcalf@mellanox.com> [for tile]
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: John Crispin <blogic@openwrt.org>
Cc: Lennox Wu <lennox.wu@gmail.com>
Cc: Ley Foon Tan <lftan@altera.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-06-24 17:23:52 -07:00
David S. Miller 9ea46abe22 sparc64: Take ctx_alloc_lock properly in hugetlb_setup().
On cheetahplus chips we take the ctx_alloc_lock in order to
modify the TLB lookup parameters for the indexed TLBs, which
are stored in the context register.

This is called with interrupts disabled, however ctx_alloc_lock
is an IRQ safe lock, therefore we must take acquire/release it
properly with spin_{lock,unlock}_irq().

Reported-by: Meelis Roos <mroos@linux.ee>
Tested-by: Meelis Roos <mroos@linux.ee>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-05-25 12:51:32 -07:00
Nitin Gupta 24e49ee3d7 sparc64: Reduce TLB flushes during hugepte changes
During hugepage map/unmap, TSB and TLB flushes are currently
issued at every PAGE_SIZE'd boundary which is unnecessary.
We now issue the flush at REAL_HPAGE_SIZE boundaries only.

Without this patch workloads which unmap a large hugepage
backed VMA region get CPU lockups due to excessive TLB
flush calls.

Orabug: 22365539, 22643230, 22995196

Signed-off-by: Nitin Gupta <nitin.m.gupta@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-05-20 18:44:27 -07:00
Sam Ravnborg 6b1cabe899 sparc32: drop superfluous cast in calls to __nocache_pa()
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-05-20 17:55:42 -07:00
Sam Ravnborg 6e6e41879e sparc32: fix build with STRICT_MM_TYPECHECKS
Based on recent thread on linux-arch (some weeks ago) I
decided to check how much work was required to build sparc32
with STRICT_MM_TYPECHECKS enabled.

The resulting binary (checked srmmu.o) was to my suprise smaller with
STRICT_MM_TYPECHECKS defined, than without.

As I have no working gear to test sparc32 bits at for the moment,
I did not enable STRICT_MM_TYPECHECKS - but was tempeted to do so.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-05-20 17:55:42 -07:00
Khalid Aziz c5b8b5beee sparc64: recognize and support Sonoma CPU type
Add code to recognize SPARC-Sonoma cpu correctly and update cpu hardware
caps and cpu distribution map. SPARC-Sonoma is based upon SPARC-M7 core
along with additional PCI functions added on and is reported by firmware
as "SPARC-SN".

Signed-off-by: Khalid Aziz <khalid.aziz@oracle.com>
Acked-by: Allen Pais <allen.pais@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-04-21 16:43:47 -04:00
Linus Torvalds d4dc3b2442 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc
Pull sparc fixes from David Miller:
 "Minor typing cleanup from Joe Perches, and some comment typo fixes
  from Adam Buchbinder"

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc:
  sparc: Convert naked unsigned uses to unsigned int
  sparc: Fix misspellings in comments.
2016-03-28 15:14:11 -05:00
Joe Perches 9ef595d83a sparc: Convert naked unsigned uses to unsigned int
Use the more normal kernel definition/declaration style.

Done via:

$ git ls-files arch/sparc | \
  xargs ./scripts/checkpatch.pl -f --fix-inplace --types=unspecified_int

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-03-20 21:28:58 -07:00
Linus Torvalds 643ad15d47 Merge branch 'mm-pkeys-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 protection key support from Ingo Molnar:
 "This tree adds support for a new memory protection hardware feature
  that is available in upcoming Intel CPUs: 'protection keys' (pkeys).

  There's a background article at LWN.net:

      https://lwn.net/Articles/643797/

  The gist is that protection keys allow the encoding of
  user-controllable permission masks in the pte.  So instead of having a
  fixed protection mask in the pte (which needs a system call to change
  and works on a per page basis), the user can map a (handful of)
  protection mask variants and can change the masks runtime relatively
  cheaply, without having to change every single page in the affected
  virtual memory range.

  This allows the dynamic switching of the protection bits of large
  amounts of virtual memory, via user-space instructions.  It also
  allows more precise control of MMU permission bits: for example the
  executable bit is separate from the read bit (see more about that
  below).

  This tree adds the MM infrastructure and low level x86 glue needed for
  that, plus it adds a high level API to make use of protection keys -
  if a user-space application calls:

        mmap(..., PROT_EXEC);

  or

        mprotect(ptr, sz, PROT_EXEC);

  (note PROT_EXEC-only, without PROT_READ/WRITE), the kernel will notice
  this special case, and will set a special protection key on this
  memory range.  It also sets the appropriate bits in the Protection
  Keys User Rights (PKRU) register so that the memory becomes unreadable
  and unwritable.

  So using protection keys the kernel is able to implement 'true'
  PROT_EXEC on x86 CPUs: without protection keys PROT_EXEC implies
  PROT_READ as well.  Unreadable executable mappings have security
  advantages: they cannot be read via information leaks to figure out
  ASLR details, nor can they be scanned for ROP gadgets - and they
  cannot be used by exploits for data purposes either.

  We know about no user-space code that relies on pure PROT_EXEC
  mappings today, but binary loaders could start making use of this new
  feature to map binaries and libraries in a more secure fashion.

  There is other pending pkeys work that offers more high level system
  call APIs to manage protection keys - but those are not part of this
  pull request.

  Right now there's a Kconfig that controls this feature
  (CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS) that is default enabled
  (like most x86 CPU feature enablement code that has no runtime
  overhead), but it's not user-configurable at the moment.  If there's
  any serious problem with this then we can make it configurable and/or
  flip the default"

* 'mm-pkeys-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (38 commits)
  x86/mm/pkeys: Fix mismerge of protection keys CPUID bits
  mm/pkeys: Fix siginfo ABI breakage caused by new u64 field
  x86/mm/pkeys: Fix access_error() denial of writes to write-only VMA
  mm/core, x86/mm/pkeys: Add execute-only protection keys support
  x86/mm/pkeys: Create an x86 arch_calc_vm_prot_bits() for VMA flags
  x86/mm/pkeys: Allow kernel to modify user pkey rights register
  x86/fpu: Allow setting of XSAVE state
  x86/mm: Factor out LDT init from context init
  mm/core, x86/mm/pkeys: Add arch_validate_pkey()
  mm/core, arch, powerpc: Pass a protection key in to calc_vm_flag_bits()
  x86/mm/pkeys: Actually enable Memory Protection Keys in the CPU
  x86/mm/pkeys: Add Kconfig prompt to existing config option
  x86/mm/pkeys: Dump pkey from VMA in /proc/pid/smaps
  x86/mm/pkeys: Dump PKRU with other kernel registers
  mm/core, x86/mm/pkeys: Differentiate instruction fetches
  x86/mm/pkeys: Optimize fault handling in access_error()
  mm/core: Do not enforce PKEY permissions on remote mm access
  um, pkeys: Add UML arch_*_access_permitted() methods
  mm/gup, x86/mm/pkeys: Check VMAs and PTEs for protection keys
  x86/mm/gup: Simplify get_user_pages() PTE bit handling
  ...
2016-03-20 19:08:56 -07:00
Kirill A. Shutemov 3ed3a4f0dd mm: cleanup *pte_alloc* interfaces
There are few things about *pte_alloc*() helpers worth cleaning up:

 - 'vma' argument is unused, let's drop it;

 - most __pte_alloc() callers do speculative check for pmd_none(),
   before taking ptl: let's introduce pte_alloc() macro which does
   the check.

   The only direct user of __pte_alloc left is userfaultfd, which has
   different expectation about atomicity wrt pmd.

 - pte_alloc_map() and pte_alloc_map_lock() are redefined using
   pte_alloc().

[sudeep.holla@arm.com: fix build for arm64 hugetlbpage]
[sfr@canb.auug.org.au: fix arch/arm/mm/mmu.c some more]
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-17 15:09:34 -07:00
Dave Hansen d4edcf0d56 mm/gup: Switch all callers of get_user_pages() to not pass tsk/mm
We will soon modify the vanilla get_user_pages() so it can no
longer be used on mm/tasks other than 'current/current->mm',
which is by far the most common way it is called.  For now,
we allow the old-style calls, but warn when they are used.
(implemented in previous patch)

This patch switches all callers of:

	get_user_pages()
	get_user_pages_unlocked()
	get_user_pages_locked()

to stop passing tsk/mm so they will no longer see the warnings.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrea Arcangeli <aarcange@redhat.com>
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: Dave Hansen <dave@sr71.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: jack@suse.cz
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20160212210156.113E9407@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-02-16 10:11:12 +01:00
Toshi Kani 35d98e93fe arch: Set IORESOURCE_SYSTEM_RAM flag for System RAM
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: Toshi Kani <toshi.kani@hpe.com>
Signed-off-by: Borislav 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.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-01-30 09:49:57 +01:00
Kirill A. Shutemov 99f1bc0116 sparc, thp: remove infrastructure for handling splitting PMDs
With new refcounting we don't need to mark PMDs splitting.  Let's drop
code to handle this.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-15 17:56:32 -08:00
Kirill A. Shutemov ddc58f27f9 mm: drop tail page refcounting
Tail page refcounting is utterly complicated and painful to support.

It uses ->_mapcount on tail pages to store how many times this page is
pinned.  get_page() bumps ->_mapcount on tail page in addition to
->_count on head.  This information is required by split_huge_page() to
be able to distribute pins from head of compound page to tails during
the split.

We will need ->_mapcount to account PTE mappings of subpages of the
compound page.  We eliminate need in current meaning of ->_mapcount in
tail pages by forbidding split entirely if the page is pinned.

The only user of tail page refcounting is THP which is marked BROKEN for
now.

Let's drop all this mess.  It makes get_page() and put_page() much
simpler.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Tested-by: Sasha Levin <sasha.levin@oracle.com>
Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Jerome Marchand <jmarchan@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-15 17:56:32 -08:00
Nitin Gupta 36beca6571 sparc64: Fix numa node distance initialization
Orabug: 22495713

Currently, NUMA node distance matrix is initialized only
when a machine descriptor (MD) exists. However, sun4u
machines (e.g. Sun Blade 2500) do not have an MD and thus
distance values were left uninitialized. The initialization
is now moved such that it happens on both sun4u and sun4v.

Signed-off-by: Nitin Gupta <nitin.m.gupta@oracle.com>
Tested-by: Mikael Pettersson <mikpelinux@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-01-14 16:58:59 -05:00
Nitin Gupta 52708d690b sparc64: Fix numa distance values
Orabug: 21896119

Use machine descriptor (MD) to get node latency
values instead of just using default values.

Testing:
On an T5-8 system with:
 - total nodes = 8
 - self latencies = 0x26d18
 - latency to other nodes = 0x3a598
   => latency ratio = ~1.5

output of numactl --hardware

 - before fix:

node distances:
node   0   1   2   3   4   5   6   7
  0:  10  20  20  20  20  20  20  20
  1:  20  10  20  20  20  20  20  20
  2:  20  20  10  20  20  20  20  20
  3:  20  20  20  10  20  20  20  20
  4:  20  20  20  20  10  20  20  20
  5:  20  20  20  20  20  10  20  20
  6:  20  20  20  20  20  20  10  20
  7:  20  20  20  20  20  20  20  10

 - after fix:

node distances:
node   0   1   2   3   4   5   6   7
  0:  10  15  15  15  15  15  15  15
  1:  15  10  15  15  15  15  15  15
  2:  15  15  10  15  15  15  15  15
  3:  15  15  15  10  15  15  15  15
  4:  15  15  15  15  10  15  15  15
  5:  15  15  15  15  15  10  15  15
  6:  15  15  15  15  15  15  10  15
  7:  15  15  15  15  15  15  15  10

Signed-off-by: Nitin Gupta <nitin.m.gupta@oracle.com>
Reviewed-by: Chris Hyser <chris.hyser@oracle.com>
Reviewed-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-11-04 12:14:49 -08:00
David Ahern 2bf7c3efc3 sparc64: Convert BUG_ON to warning
Pagefault handling has a BUG_ON path that panics the system. Convert it to
a warning instead. There is no need to bring down the system for this kind
of failure.

The following was hit while running:
    perf sched record -g -- make -j 16

[3609412.782801] kernel BUG at /opt/dahern/linux.git/arch/sparc/mm/fault_64.c:416!
[3609412.782833]               \|/ ____ \|/
[3609412.782833]               "@'/ .. \`@"
[3609412.782833]               /_| \__/ |_\
[3609412.782833]                  \__U_/
[3609412.782870] cat(4516): Kernel bad sw trap 5 [#1]
[3609412.782889] CPU: 0 PID: 4516 Comm: cat Tainted: G            E   4.1.0-rc8+ #6
[3609412.782909] task: fff8000126e31f80 ti: fff8000110d90000 task.ti: fff8000110d90000
[3609412.782931] TSTATE: 0000004411001603 TPC: 000000000096b164 TNPC: 000000000096b168 Y: 0000004e    Tainted: G            E
[3609412.782964] TPC: <do_sparc64_fault+0x5e4/0x6a0>
[3609412.782979] g0: 000000000096abe0 g1: 0000000000d314c4 g2: 0000000000000000 g3: 0000000000000001
[3609412.783009] g4: fff8000126e31f80 g5: fff80001302d2000 g6: fff8000110d90000 g7: 00000000000000ff
[3609412.783045] o0: 0000000000aff6a8 o1: 00000000000001a0 o2: 0000000000000001 o3: 0000000000000054
[3609412.783080] o4: fff8000100026820 o5: 0000000000000001 sp: fff8000110d935f1 ret_pc: 000000000096b15c
[3609412.783117] RPC: <do_sparc64_fault+0x5dc/0x6a0>
[3609412.783137] l0: 000007feff996000 l1: 0000000000030001 l2: 0000000000000004 l3: fff8000127bd0120
[3609412.783174] l4: 0000000000000054 l5: fff8000127bd0188 l6: 0000000000000000 l7: fff8000110d9dba8
[3609412.783210] i0: fff8000110d93f60 i1: fff8000110ca5530 i2: 000000000000003f i3: 0000000000000054
[3609412.783244] i4: fff800010000081a i5: fff8000100000398 i6: fff8000110d936a1 i7: 0000000000407c6c
[3609412.783286] I7: <sparc64_realfault_common+0x10/0x20>
[3609412.783308] Call Trace:
[3609412.783329]  [0000000000407c6c] sparc64_realfault_common+0x10/0x20
[3609412.783353] Disabling lock debugging due to kernel taint
[3609412.783379] Caller[0000000000407c6c]: sparc64_realfault_common+0x10/0x20
[3609412.783449] Caller[fff80001002283e4]: 0xfff80001002283e4
[3609412.783471] Instruction DUMP: 921021a0  7feaff91  901222a8 <91d02005> 82086100  02f87f7b  808a2873  81cfe008  01000000
[3609412.783542] Kernel panic - not syncing: Fatal exception
[3609412.784605] Press Stop-A (L1-A) to return to the boot prom
[3609412.784615] ---[ end Kernel panic - not syncing: Fatal exception

With this patch rather than a panic I occasionally get something like this:
    perf sched record -g -m 1024  -- make -j N

where N is based on number of cpus (128 to 1024 for a T7-4 and 8 for an 8 cpu
VM on a T5-2).

WARNING: CPU: 211 PID: 52565 at /opt/dahern/linux.git/arch/sparc/mm/fault_64.c:417 do_sparc64_fault+0x340/0x70c()
address (7feffcd6000) != regs->tpc (fff80001004873c0)
Modules linked in: ipt_REJECT nf_reject_ipv4 nf_conntrack_ipv4 nf_defrag_ipv4 iptable_filter ip_tables ip6t_REJECT nf_reject_ipv6 xt_tcpudp nf_conntrack_ipv6 nf_defrag_ipv6 xt_state nf_conntrack ip6table_filter ip6_tables x_tables ipv6 cdc_ether usbnet mii ixgbe mdio igb i2c_algo_bit i2c_core ptp crc32c_sparc64 camellia_sparc64 des_sparc64 des_generic md5_sparc64 sha512_sparc64 sha1_sparc64 uio_pdrv_genirq uio usb_storage mpt3sas scsi_transport_sas raid_class aes_sparc64 sunvnet sunvdc sha256_sparc64(E) sha256_generic(E)
CPU: 211 PID: 52565 Comm: ld Tainted: G        W   E   4.1.0-rc8+ #19
Call Trace:
 [000000000045ce30] warn_slowpath_common+0x7c/0xa0
 [000000000045ceec] warn_slowpath_fmt+0x30/0x40
 [000000000098ad64] do_sparc64_fault+0x340/0x70c
 [0000000000407c2c] sparc64_realfault_common+0x10/0x20
---[ end trace 62ee02065a01a049 ]---
ld[52565]: segfault at fff80001004873c0 ip fff80001004873c0 (rpc fff8000100158868) sp 000007feffcd70e1 error 30002 in libc-2.12.so[fff8000100410000+184000]

The segfault is horrible, but better than a system panic.

An 8-cpu VM on a T5-2 also showed the above traces from time to time,
so it is a general problem and not specific to the T7 or baremetal.

Signed-off-by: David Ahern <david.ahern@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-06-25 06:01:02 -07:00
Tony Luck fc6daaf931 mm/memblock: add extra "flags" to memblock to allow selection of memory based on attribute
Some high end Intel Xeon systems report uncorrectable memory errors as a
recoverable machine check.  Linux has included code for some time to
process these and just signal the affected processes (or even recover
completely if the error was in a read only page that can be replaced by
reading from disk).

But we have no recovery path for errors encountered during kernel code
execution.  Except for some very specific cases were are unlikely to ever
be able to recover.

Enter memory mirroring. Actually 3rd generation of memory mirroing.

Gen1: All memory is mirrored
	Pro: No s/w enabling - h/w just gets good data from other side of the
	     mirror
	Con: Halves effective memory capacity available to OS/applications

Gen2: Partial memory mirror - just mirror memory begind some memory controllers
	Pro: Keep more of the capacity
	Con: Nightmare to enable. Have to choose between allocating from
	     mirrored memory for safety vs. NUMA local memory for performance

Gen3: Address range partial memory mirror - some mirror on each memory
      controller
	Pro: Can tune the amount of mirror and keep NUMA performance
	Con: I have to write memory management code to implement

The current plan is just to use mirrored memory for kernel allocations.
This has been broken into two phases:

1) This patch series - find the mirrored memory, use it for boot time
   allocations

2) Wade into mm/page_alloc.c and define a ZONE_MIRROR to pick up the
   unused mirrored memory from mm/memblock.c and only give it out to
   select kernel allocations (this is still being scoped because
   page_alloc.c is scary).

This patch (of 3):

Add extra "flags" to memblock to allow selection of memory based on
attribute.  No functional changes

Signed-off-by: Tony Luck <tony.luck@intel.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Hanjun Guo <guohanjun@huawei.com>
Cc: Xiexiuqi <xiexiuqi@huawei.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24 17:49:44 -07:00
Zhang Zhen e81f2d2237 mm/hugetlb: reduce arch dependent code about huge_pmd_unshare
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 <zhenzhang.zhang@huawei.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: David Rientjes <rientjes@google.com>
Cc: James Yang <James.Yang@freescale.com>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24 17:49:41 -07:00
Ingo Molnar f407a82586 Merge branch 'linus' into sched/core, to resolve conflict
Conflicts:
	arch/sparc/include/asm/topology_64.h

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-06-02 08:05:42 +02:00
Khalid Aziz 494e5b6fae sparc: Resolve conflict between sparc v9 and M7 on usage of bit 9 of TTE
sparc: Resolve conflict between sparc v9 and M7 on usage of bit 9 of TTE

Bit 9 of TTE is CV (Cacheable in V-cache) on sparc v9 processor while
the same bit 9 is MCDE (Memory Corruption Detection Enable) on M7
processor. This creates a conflicting usage of the same bit. Kernel
sets TTE.cv bit on all pages for sun4v architecture which works well
for sparc v9 but enables memory corruption detection on M7 processor
which is not the intent. This patch adds code to determine if kernel
is running on M7 processor and takes steps to not enable memory
corruption detection in TTE erroneously.

Signed-off-by: Khalid Aziz <khalid.aziz@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-05-31 22:15:01 -07:00
David Hildenbrand 70ffdb9393 mm/fault, arch: Use pagefault_disable() to check for disabled pagefaults in the handler
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 <tglx@linutronix.de>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: David.Laight@ACULAB.COM
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
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 <mingo@kernel.org>
2015-05-19 08:39:15 +02:00
David Hildenbrand 2cb7c9cb42 sched/preempt, mm/kmap: Explicitly disable/enable preemption in kmap_atomic_*
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 <tglx@linutronix.de>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: David.Laight@ACULAB.COM
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
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 <mingo@kernel.org>
2015-05-19 08:39:14 +02:00
David S. Miller 3c08158e0e sparc: Fix /proc/kcore
/proc/kcore investigates the "System RAM" elements in /proc/iomem to
initialize it's memory tables.  Therefore we have to register them
before it tries to do so.  kcore uses device_initcall() so let's
use arch_initcall() for the registry.

Also we need ARCH_PROC_KCORE_TEXT to get the virtual addresses of
the kernel image correct.

Reported-by: David Ahern <david.ahern@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-03-18 19:15:28 -07:00
Andrea Arcangeli a7b780750e mm: gup: use get_user_pages_unlocked within get_user_pages_fast
This allows the get_user_pages_fast slow path to release the mmap_sem
before blocking.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andres Lagar-Cavilla <andreslc@google.com>
Cc: Peter Feiner <pfeiner@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-11 17:06:05 -08:00
Naoya Horiguchi 61f77eda9b mm/hugetlb: reduce arch dependent code around follow_huge_*
Currently we have many duplicates in definitions around
follow_huge_addr(), follow_huge_pmd(), and follow_huge_pud(), so this
patch tries to remove the m.  The basic idea is to put the default
implementation for these functions in mm/hugetlb.c as weak symbols
(regardless of CONFIG_ARCH_WANT_GENERAL_HUGETL B), and to implement
arch-specific code only when the arch needs it.

For follow_huge_addr(), only powerpc and ia64 have their own
implementation, and in all other architectures this function just returns
ERR_PTR(-EINVAL).  So this patch sets returning ERR_PTR(-EINVAL) as
default.

As for follow_huge_(pmd|pud)(), if (pmd|pud)_huge() is implemented to
always return 0 in your architecture (like in ia64 or sparc,) it's never
called (the callsite is optimized away) no matter how implemented it is.
So in such architectures, we don't need arch-specific implementation.

In some architecture (like mips, s390 and tile,) their current
arch-specific follow_huge_(pmd|pud)() are effectively identical with the
common code, so this patch lets these architecture use the common code.

One exception is metag, where pmd_huge() could return non-zero but it
expects follow_huge_pmd() to always return NULL.  This means that we need
arch-specific implementation which returns NULL.  This behavior looks
strange to me (because non-zero pmd_huge() implies that the architecture
supports PMD-based hugepage, so follow_huge_pmd() can/should return some
relevant value,) but that's beyond this cleanup patch, so let's keep it.

Justification of non-trivial changes:
- in s390, follow_huge_pmd() checks !MACHINE_HAS_HPAGE at first, and this
  patch removes the check. This is OK because we can assume MACHINE_HAS_HPAGE
  is true when follow_huge_pmd() can be called (note that pmd_huge() has
  the same check and always returns 0 for !MACHINE_HAS_HPAGE.)
- in s390 and mips, we use HPAGE_MASK instead of PMD_MASK as done in common
  code. This patch forces these archs use PMD_MASK, but it's OK because
  they are identical in both archs.
  In s390, both of HPAGE_SHIFT and PMD_SHIFT are 20.
  In mips, HPAGE_SHIFT is defined as (PAGE_SHIFT + PAGE_SHIFT - 3) and
  PMD_SHIFT is define as (PAGE_SHIFT + PAGE_SHIFT + PTE_ORDER - 3), but
  PTE_ORDER is always 0, so these are identical.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Nishanth Aravamudan <nacc@linux.vnet.ibm.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Steve Capper <steve.capper@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-11 17:06:01 -08:00
Linus Torvalds 33692f2759 vm: add VM_FAULT_SIGSEGV handling support
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 fee7e49d45 ("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 <tiwai@suse.de>
Tested-by: Jan Engelhardt <jengelh@inai.de>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> # "s390 still compiles and boots"
Cc: linux-arch@vger.kernel.org
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-01-29 10:51:32 -08:00
Andreas Larsson 66d0f7ec9f sparc32: destroy_context() and switch_mm() needs to disable interrupts.
Load balancing can be triggered in the critical sections protected by
srmmu_context_spinlock in destroy_context() and switch_mm() and can hang
the cpu waiting for the rq lock of another cpu that in turn has called
switch_mm hangning on srmmu_context_spinlock leading to deadlock.

So, disable interrupt while taking srmmu_context_spinlock in
destroy_context() and switch_mm() so we don't deadlock.

See also commit 77b838fa1e ("[SPARC64]: destroy_context() needs to disable
interrupts.")

Signed-off-by: Andreas Larsson <andreas@gaisler.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-12-18 12:47:54 -05:00
Joonsoo Kim 031bc5743f mm/debug-pagealloc: make debug-pagealloc boottime configurable
Now, we have prepared to avoid using debug-pagealloc in boottime.  So
introduce new kernel-parameter to disable debug-pagealloc in boottime, and
makes related functions to be disabled in this case.

Only non-intuitive part is change of guard page functions.  Because guard
page is effective only if debug-pagealloc is enabled, turning off
according to debug-pagealloc is reasonable thing to do.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Dave Hansen <dave@sr71.net>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Jungsoo Son <jungsoo.son@lge.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-12-13 12:42:48 -08:00
David S. Miller 06090e8ed8 sparc64: Implement __get_user_pages_fast().
It is not sufficient to only implement get_user_pages_fast(), you
must also implement the atomic version __get_user_pages_fast()
otherwise you end up using the weak symbol fallback implementation
which simply returns zero.

This is dangerous, because it causes the futex code to loop forever
if transparent hugepages are supported (see get_futex_key()).

Signed-off-by: David S. Miller <davem@davemloft.net>
2014-10-24 09:59:02 -07:00
Linus Torvalds 0429fbc0bd Merge branch 'for-3.18-consistent-ops' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu
Pull percpu consistent-ops changes from Tejun Heo:
 "Way back, before the current percpu allocator was implemented, static
  and dynamic percpu memory areas were allocated and handled separately
  and had their own accessors.  The distinction has been gone for many
  years now; however, the now duplicate two sets of accessors remained
  with the pointer based ones - this_cpu_*() - evolving various other
  operations over time.  During the process, we also accumulated other
  inconsistent operations.

  This pull request contains Christoph's patches to clean up the
  duplicate accessor situation.  __get_cpu_var() uses are replaced with
  with this_cpu_ptr() and __this_cpu_ptr() with raw_cpu_ptr().

  Unfortunately, the former sometimes is tricky thanks to C being a bit
  messy with the distinction between lvalues and pointers, which led to
  a rather ugly solution for cpumask_var_t involving the introduction of
  this_cpu_cpumask_var_ptr().

  This converts most of the uses but not all.  Christoph will follow up
  with the remaining conversions in this merge window and hopefully
  remove the obsolete accessors"

* 'for-3.18-consistent-ops' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: (38 commits)
  irqchip: Properly fetch the per cpu offset
  percpu: Resolve ambiguities in __get_cpu_var/cpumask_var_t -fix
  ia64: sn_nodepda cannot be assigned to after this_cpu conversion. Use __this_cpu_write.
  percpu: Resolve ambiguities in __get_cpu_var/cpumask_var_t
  Revert "powerpc: Replace __get_cpu_var uses"
  percpu: Remove __this_cpu_ptr
  clocksource: Replace __this_cpu_ptr with raw_cpu_ptr
  sparc: Replace __get_cpu_var uses
  avr32: Replace __get_cpu_var with __this_cpu_write
  blackfin: Replace __get_cpu_var uses
  tile: Use this_cpu_ptr() for hardware counters
  tile: Replace __get_cpu_var uses
  powerpc: Replace __get_cpu_var uses
  alpha: Replace __get_cpu_var
  ia64: Replace __get_cpu_var uses
  s390: cio driver &__get_cpu_var replacements
  s390: Replace __get_cpu_var uses
  mips: Replace __get_cpu_var uses
  MIPS: Replace __get_cpu_var uses in FPU emulator.
  arm: Replace __this_cpu_ptr with raw_cpu_ptr
  ...
2014-10-15 07:48:18 +02:00
David S. Miller d195b71bad sparc64: Kill unnecessary tables and increase MAX_BANKS.
swapper_low_pmd_dir and swapper_pud_dir are actually completely
useless and unnecessary.

We just need swapper_pg_dir[].  Naturally the other page table chunks
will be allocated on an as-needed basis.  Since the kernel actually
accesses these tables in the PAGE_OFFSET view, there is not even a TLB
locality advantage of placing them in the kernel image.

Use the hard coded vmlinux.ld.S slot for swapper_pg_dir which is
naturally page aligned.

Increase MAX_BANKS to 1024 in order to handle heavily fragmented
virtual guests.

Even with this MAX_BANKS increase, the kernel is 20K+ smaller.

Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Bob Picco <bob.picco@oracle.com>
2014-10-05 16:53:40 -07:00
David S. Miller bb4e6e85da sparc64: Adjust vmalloc region size based upon available virtual address bits.
In order to accomodate embedded per-cpu allocation with large numbers
of cpus and numa nodes, we have to use as much virtual address space
as possible for the vmalloc region.  Otherwise we can get things like:

PERCPU: max_distance=0x380001c10000 too large for vmalloc space 0xff00000000

So, once we select a value for PAGE_OFFSET, derive the size of the
vmalloc region based upon that.

Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Bob Picco <bob.picco@oracle.com>
2014-10-05 16:53:40 -07:00
David S. Miller 7c0fa0f24b sparc64: Increase MAX_PHYS_ADDRESS_BITS to 53.
Make sure, at compile time, that the kernel can properly support
whatever MAX_PHYS_ADDRESS_BITS is defined to.

On M7 chips, use a max_phys_bits value of 49.

Based upon a patch by Bob Picco.

Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Bob Picco <bob.picco@oracle.com>
2014-10-05 16:53:40 -07:00
David S. Miller c06240c7f5 sparc64: Use kernel page tables for vmemmap.
For sparse memory configurations, the vmemmap array behaves terribly
and it takes up an inordinate amount of space in the BSS section of
the kernel image unconditionally.

Just build huge PMDs and look them up just like we do for TLB misses
in the vmalloc area.

Kernel BSS shrinks by about 2MB.

Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Bob Picco <bob.picco@oracle.com>
2014-10-05 16:53:39 -07:00
David S. Miller 0dd5b7b09e sparc64: Fix physical memory management regressions with large max_phys_bits.
If max_phys_bits needs to be > 43 (f.e. for T4 chips), things like
DEBUG_PAGEALLOC stop working because the 3-level page tables only
can cover up to 43 bits.

Another problem is that when we increased MAX_PHYS_ADDRESS_BITS up to
47, several statically allocated tables became enormous.

Compounding this is that we will need to support up to 49 bits of
physical addressing for M7 chips.

The two tables in question are sparc64_valid_addr_bitmap and
kpte_linear_bitmap.

The first holds a bitmap, with 1 bit for each 4MB chunk of physical
memory, indicating whether that chunk actually exists in the machine
and is valid.

The second table is a set of 2-bit values which tell how large of a
mapping (4MB, 256MB, 2GB, 16GB, respectively) we can use at each 256MB
chunk of ram in the system.

These tables are huge and take up an enormous amount of the BSS
section of the sparc64 kernel image.  Specifically, the
sparc64_valid_addr_bitmap is 4MB, and the kpte_linear_bitmap is 128K.

So let's solve the space wastage and the DEBUG_PAGEALLOC problem
at the same time, by using the kernel page tables (as designed) to
manage this information.

We have to keep using large mappings when DEBUG_PAGEALLOC is disabled,
and we do this by encoding huge PMDs and PUDs.

On a T4-2 with 256GB of ram the kernel page table takes up 16K with
DEBUG_PAGEALLOC disabled and 256MB with it enabled.  Furthermore, this
memory is dynamically allocated at run time rather than coded
statically into the kernel image.

Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Bob Picco <bob.picco@oracle.com>
2014-10-05 16:53:39 -07:00
David S. Miller 8c82dc0e88 sparc64: Adjust KTSB assembler to support larger physical addresses.
As currently coded the KTSB accesses in the kernel only support up to
47 bits of physical addressing.

Adjust the instruction and patching sequence in order to support
arbitrary 64 bits addresses.

Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Bob Picco <bob.picco@oracle.com>
2014-10-05 16:53:39 -07:00
David S. Miller 4397bed080 sparc64: Define VA hole at run time, rather than at compile time.
Now that we use 4-level page tables, we can provide up to 53-bits of
virtual address space to the user.

Adjust the VA hole based upon the capabilities of the cpu type probed.

Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Bob Picco <bob.picco@oracle.com>
2014-10-05 16:53:39 -07:00
David S. Miller ac55c76814 sparc64: Switch to 4-level page tables.
This has become necessary with chips that support more than 43-bits
of physical addressing.

Based almost entirely upon a patch by Bob Picco.

Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Bob Picco <bob.picco@oracle.com>
2014-10-05 16:53:38 -07:00
David S. Miller 473ad7f4fb sparc64: Fix reversed start/end in flush_tlb_kernel_range()
When we have to split up a flush request into multiple pieces
(in order to avoid the firmware range) we don't specify the
arguments in the right order for the second piece.

Fix the order, or else we get hangs as the code tries to
flush "a lot" of entries and we get lockups like this:

[ 4422.981276] NMI watchdog: BUG: soft lockup - CPU#12 stuck for 23s! [expect:117032]
[ 4422.996130] Modules linked in: ipv6 loop usb_storage igb ptp sg sr_mod ehci_pci ehci_hcd pps_core n2_rng rng_core
[ 4423.016617] CPU: 12 PID: 117032 Comm: expect Not tainted 3.17.0-rc4+ #1608
[ 4423.030331] task: fff8003cc730e220 ti: fff8003d99d54000 task.ti: fff8003d99d54000
[ 4423.045282] TSTATE: 0000000011001602 TPC: 00000000004521e8 TNPC: 00000000004521ec Y: 00000000    Not tainted
[ 4423.064905] TPC: <__flush_tlb_kernel_range+0x28/0x40>
[ 4423.074964] g0: 000000000052fd10 g1: 00000001295a8000 g2: ffffff7176ffc000 g3: 0000000000002000
[ 4423.092324] g4: fff8003cc730e220 g5: fff8003dfedcc000 g6: fff8003d99d54000 g7: 0000000000000006
[ 4423.109687] o0: 0000000000000000 o1: 0000000000000000 o2: 0000000000000003 o3: 00000000f0000000
[ 4423.127058] o4: 0000000000000080 o5: 00000001295a8000 sp: fff8003d99d56d01 ret_pc: 000000000052ff54
[ 4423.145121] RPC: <__purge_vmap_area_lazy+0x314/0x3a0>
[ 4423.155185] l0: 0000000000000000 l1: 0000000000000000 l2: 0000000000a38040 l3: 0000000000000000
[ 4423.172559] l4: fff8003dae8965e0 l5: ffffffffffffffff l6: 0000000000000000 l7: 00000000f7e2b138
[ 4423.189913] i0: fff8003d99d576a0 i1: fff8003d99d576a8 i2: fff8003d99d575e8 i3: 0000000000000000
[ 4423.207284] i4: 0000000000008008 i5: fff8003d99d575c8 i6: fff8003d99d56df1 i7: 0000000000530c24
[ 4423.224640] I7: <free_vmap_area_noflush+0x64/0x80>
[ 4423.234193] Call Trace:
[ 4423.239051]  [0000000000530c24] free_vmap_area_noflush+0x64/0x80
[ 4423.251029]  [0000000000531a7c] remove_vm_area+0x5c/0x80
[ 4423.261628]  [0000000000531b80] __vunmap+0x20/0x120
[ 4423.271352]  [000000000071cf18] n_tty_close+0x18/0x40
[ 4423.281423]  [00000000007222b0] tty_ldisc_close+0x30/0x60
[ 4423.292183]  [00000000007225a4] tty_ldisc_reinit+0x24/0xa0
[ 4423.303120]  [0000000000722ab4] tty_ldisc_hangup+0xd4/0x1e0
[ 4423.314232]  [0000000000719aa0] __tty_hangup+0x280/0x3c0
[ 4423.324835]  [0000000000724cb4] pty_close+0x134/0x1a0
[ 4423.334905]  [000000000071aa24] tty_release+0x104/0x500
[ 4423.345316]  [00000000005511d0] __fput+0x90/0x1e0
[ 4423.354701]  [000000000047fa54] task_work_run+0x94/0xe0
[ 4423.365126]  [0000000000404b44] __handle_signal+0xc/0x2c

Fixes: 4ca9a23765 ("sparc64: Guard against flushing openfirmware mappings.")
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-10-04 21:05:14 -07:00
bob picco 7c21d533ab sparc64: mem boot option correction
The "mem" boot option can result in many unexpected consequences. This patch
attempts to prevent boot hangs which have been experienced on T4-4 and T5-8.
Basically the boot loader allocates vmlinuz and initrd higher in available
OBP physical memory. For example, on a 2Tb T5-8 it isn't possible to boot
with mem=20G.

The patch utilizes memblock to avoid reserved regions and trim memory which
is only free. Other improvements are possible for a multi-node machine.

This is a snippet of the boot log with mem=20G on T5-8 with the patch applied:
MEMBLOCK configuration:	<- before memory reduction
 memory size = 0x1ffad6ce000 reserved size = 0xa1adf44
 memory.cnt  = 0xb
 memory[0x0]    [0x00000030400000-0x00003fdde47fff], 0x3fada48000 bytes
 memory[0x1]    [0x00003fdde4e000-0x00003fdde4ffff], 0x2000 bytes
 memory[0x2]    [0x00080000000000-0x00083fffffffff], 0x4000000000 bytes
 memory[0x3]    [0x00100000000000-0x00103fffffffff], 0x4000000000 bytes
 memory[0x4]    [0x00180000000000-0x00183fffffffff], 0x4000000000 bytes
 memory[0x5]    [0x00200000000000-0x00203fffffffff], 0x4000000000 bytes
 memory[0x6]    [0x00280000000000-0x00283fffffffff], 0x4000000000 bytes
 memory[0x7]    [0x00300000000000-0x00303fffffffff], 0x4000000000 bytes
 memory[0x8]    [0x00380000000000-0x00383fffc71fff], 0x3fffc72000 bytes
 memory[0x9]    [0x00383fffc92000-0x00383fffca1fff], 0x10000 bytes
 memory[0xa]    [0x00383fffcb4000-0x00383fffcb5fff], 0x2000 bytes
 reserved.cnt  = 0x2
 reserved[0x0]  [0x00380000000000-0x0038000117e7f8], 0x117e7f9 bytes
 reserved[0x1]  [0x00380004000000-0x0038000d02f74a], 0x902f74b bytes
...
MEMBLOCK configuration:	<- after reduction of memory
 memory size = 0x50a1adf44 reserved size = 0xa1adf44
 memory.cnt  = 0x4
 memory[0x0]    [0x00380000000000-0x0038000117e7f8], 0x117e7f9 bytes
 memory[0x1]    [0x00380004000000-0x0038050d01d74a], 0x50901d74b bytes
 memory[0x2]    [0x00383fffc92000-0x00383fffca1fff], 0x10000 bytes
 memory[0x3]    [0x00383fffcb4000-0x00383fffcb5fff], 0x2000 bytes
 reserved.cnt  = 0x2
 reserved[0x0]  [0x00380000000000-0x0038000117e7f8], 0x117e7f9 bytes
 reserved[0x1]  [0x00380004000000-0x0038000d02f74a], 0x902f74b bytes
...
Early memory node ranges
  node   7: [mem 0x380000000000-0x38000117dfff]
  node   7: [mem 0x380004000000-0x380f0d01bfff]
  node   7: [mem 0x383fffc92000-0x383fffca1fff]
  node   7: [mem 0x383fffcb4000-0x383fffcb5fff]
Could not find start_pfn for node 0
Could not find start_pfn for node 1
Could not find start_pfn for node 2
Could not find start_pfn for node 3
Could not find start_pfn for node 4
Could not find start_pfn for node 5
Could not find start_pfn for node 6
.

The patch was tested on T4-1, T5-8 and Jalap?no.

Cc: sparclinux@vger.kernel.org
Signed-off-by: Bob Picco <bob.picco@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-16 18:23:11 -07:00
bob picco 3dee9df548 sparc64: find_node adjustment
We have seen an issue with guest boot into LDOM that causes early boot failures
because of no matching rules for node identitity of the memory. I analyzed this
on my T4 and concluded there might not be a solution. I saw the issue in
mainline too when booting into the control/primary domain - with guests
configured.  Note, this could be a firmware bug on some older machines.

I'll provide a full explanation of the issues below. Should we not find a
matching BEST latency group for a real address (RA) then we will assume node 0.
On the T4-2 here with the information provided I can't see an alternative.

Technically the LDOM shown below should match the MBLOCK to the
favorable latency group. However other factors must be considered too. Were
the memory controllers configured "fine" grained interleave or "coarse"
grain interleaved -  T4. Also should a "group" MD node be considered a NUMA
node?

There has to be at least one Machine Description (MD) "group" and hence one
NUMA node. The group can have one or more latency groups (lg) - more than one
memory controller. The current code chooses the smallest latency as the most
favorable per group. The latency and lg information is in MLGROUP below.
MBLOCK is the base and size of the RAs for the machine as fetched from OBP
/memory "available" property. My machine has one MBLOCK but more would be
possible - with holes?

For a T4-2 the following information has been gathered:
with LDOM guest
MEMBLOCK configuration:
 memory size = 0x27f870000
 memory.cnt  = 0x3
 memory[0x0]    [0x00000020400000-0x0000029fc67fff], 0x27f868000 bytes
 memory[0x1]    [0x0000029fd8a000-0x0000029fd8bfff], 0x2000 bytes
 memory[0x2]    [0x0000029fd92000-0x0000029fd97fff], 0x6000 bytes
 reserved.cnt  = 0x2
 reserved[0x0]  [0x00000020800000-0x000000216c15c0], 0xec15c1 bytes
 reserved[0x1]  [0x00000024800000-0x0000002c180c1e], 0x7980c1f bytes
MBLOCK[0]: base[20000000] size[280000000] offset[0]
(note: "base" and "size" reported in "MBLOCK" encompass the "memory[X]" values)
(note: (RA + offset) & mask = val is the formula to detect a match for the
memory controller. should there be no match for find_node node, a return
value of -1 resulted for the node - BAD)

There is one group. It has these forward links
MLGROUP[1]: node[545] latency[1f7e8] match[200000000] mask[200000000]
MLGROUP[2]: node[54d] latency[2de60] match[0] mask[200000000]
NUMA NODE[0]: node[545] mask[200000000] val[200000000] (latency[1f7e8])
(note: "val" is the best lg's (smallest latency) "match")

no LDOM guest - bare metal
MEMBLOCK configuration:
 memory size = 0xfdf2d0000
 memory.cnt  = 0x3
 memory[0x0]    [0x00000020400000-0x00000fff6adfff], 0xfdf2ae000 bytes
 memory[0x1]    [0x00000fff6d2000-0x00000fff6e7fff], 0x16000 bytes
 memory[0x2]    [0x00000fff766000-0x00000fff771fff], 0xc000 bytes
 reserved.cnt  = 0x2
 reserved[0x0]  [0x00000020800000-0x00000021a04580], 0x1204581 bytes
 reserved[0x1]  [0x00000024800000-0x0000002c7d29fc], 0x7fd29fd bytes
MBLOCK[0]: base[20000000] size[fe0000000] offset[0]

there are two groups
group node[16d5]
MLGROUP[0]: node[1765] latency[1f7e8] match[0] mask[200000000]
MLGROUP[3]: node[177d] latency[2de60] match[200000000] mask[200000000]
NUMA NODE[0]: node[1765] mask[200000000] val[0] (latency[1f7e8])
group node[171d]
MLGROUP[2]: node[1775] latency[2de60] match[0] mask[200000000]
MLGROUP[1]: node[176d] latency[1f7e8] match[200000000] mask[200000000]
NUMA NODE[1]: node[176d] mask[200000000] val[200000000] (latency[1f7e8])
(note: for this two "group" bare metal machine, 1/2 memory is in group one's
lg and 1/2 memory is in group two's lg).

Cc: sparclinux@vger.kernel.org
Signed-off-by: Bob Picco <bob.picco@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-16 17:55:09 -07:00
bob picco 4ccb927289 sparc64: sun4v TLB error power off events
We've witnessed a few TLB events causing the machine to power off because
of prom_halt. In one case it was some nfs related area during rmmod. Another
was an mmapper of /dev/mem. A more recent one is an ITLB issue with
a bad pagesize which could be a hardware bug. Bugs happen but we should
attempt to not power off the machine and/or hang it when possible.

This is a DTLB error from an mmapper of /dev/mem:
[root@sparcie ~]# SUN4V-DTLB: Error at TPC[fffff80100903e6c], tl 1
SUN4V-DTLB: TPC<0xfffff80100903e6c>
SUN4V-DTLB: O7[fffff801081979d0]
SUN4V-DTLB: O7<0xfffff801081979d0>
SUN4V-DTLB: vaddr[fffff80100000000] ctx[1250] pte[98000000000f0610] error[2]
.

This is recent mainline for ITLB:
[ 3708.179864] SUN4V-ITLB: TPC<0xfffffc010071cefc>
[ 3708.188866] SUN4V-ITLB: O7[fffffc010071cee8]
[ 3708.197377] SUN4V-ITLB: O7<0xfffffc010071cee8>
[ 3708.206539] SUN4V-ITLB: vaddr[e0003] ctx[1a3c] pte[2900000dcc800eeb] error[4]
.

Normally sun4v_itlb_error_report() and sun4v_dtlb_error_report() would call
prom_halt() and drop us to OF command prompt "ok". This isn't the case for
LDOMs and the machine powers off.

For the HV reported error of HV_ENORADDR for HV HV_MMU_MAP_ADDR_TRAP we cause
a SIGBUS error by qualifying it within do_sparc64_fault() for fault code mask
of FAULT_CODE_BAD_RA. This is done when trap level (%tl) is less or equal
one("1"). Otherwise, for %tl > 1,  we proceed eventually to die_if_kernel().

The logic of this patch was partially inspired by David Miller's feedback.

Power off of large sparc64 machines is painful. Plus die_if_kernel provides
more context. A reset sequence isn't a brief period on large sparc64 but
better than power-off/power-on sequence.

Cc: sparclinux@vger.kernel.org
Signed-off-by: Bob Picco <bob.picco@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-16 17:46:44 -07:00