<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux/arch/tile, branch v4.0</title>
<subtitle>Mirror of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/
</subtitle>
<id>https://git.shady.money/linux/atom?h=v4.0</id>
<link rel='self' href='https://git.shady.money/linux/atom?h=v4.0'/>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/'/>
<updated>2015-02-14T05:21:37Z</updated>
<entry>
<title>tile: use %*pb[l] to print bitmaps including cpumasks and nodemasks</title>
<updated>2015-02-14T05:21:37Z</updated>
<author>
<name>Tejun Heo</name>
<email>tj@kernel.org</email>
</author>
<published>2015-02-13T22:37:09Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=839b268033c5d1316b2f8cf49184984e6f335fee'/>
<id>urn:sha1:839b268033c5d1316b2f8cf49184984e6f335fee</id>
<content type='text'>
printk and friends can now format bitmaps using '%*pb[l]'.  cpumask
and nodemask also provide cpumask_pr_args() and nodemask_pr_args()
respectively which can be used to generate the two printf arguments
necessary to format the specified cpu/nodemask.

Signed-off-by: Tejun Heo &lt;tj@kernel.org&gt;
Cc: Chris Metcalf &lt;cmetcalf@tilera.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>Merge git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile</title>
<updated>2015-02-13T18:43:04Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2015-02-13T18:43:04Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=f1252515d901ee2a184a9d49a7f29ae14da823eb'/>
<id>urn:sha1:f1252515d901ee2a184a9d49a7f29ae14da823eb</id>
<content type='text'>
Pull arch/tile changes from Chris Metcalf:
 "Not much in this batch, just some minor cleanups"

* git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile:
  tile: change MAINTAINERS website from tilera.com to ezchip.com
  tile: enable sparse checks for get/put_user
  tile: fix put_user sparse errors
  tile: default to little endian on older toolchains
</content>
</entry>
<entry>
<title>all arches, signal: move restart_block to struct task_struct</title>
<updated>2015-02-13T02:54:12Z</updated>
<author>
<name>Andy Lutomirski</name>
<email>luto@amacapital.net</email>
</author>
<published>2015-02-12T23:01:14Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=f56141e3e2d9aabf7e6b89680ab572c2cdbb2a24'/>
<id>urn:sha1:f56141e3e2d9aabf7e6b89680ab572c2cdbb2a24</id>
<content type='text'>
If an attacker can cause a controlled kernel stack overflow, overwriting
the restart block is a very juicy exploit target.  This is because the
restart_block is held in the same memory allocation as the kernel stack.

Moving the restart block to struct task_struct prevents this exploit by
making the restart_block harder to locate.

Note that there are other fields in thread_info that are also easy
targets, at least on some architectures.

It's also a decent simplification, since the restart code is more or less
identical on all architectures.

[james.hogan@imgtec.com: metag: align thread_info::supervisor_stack]
Signed-off-by: Andy Lutomirski &lt;luto@amacapital.net&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
Cc: "H. Peter Anvin" &lt;hpa@zytor.com&gt;
Cc: Ingo Molnar &lt;mingo@kernel.org&gt;
Cc: Kees Cook &lt;keescook@chromium.org&gt;
Cc: David Miller &lt;davem@davemloft.net&gt;
Acked-by: Richard Weinberger &lt;richard@nod.at&gt;
Cc: Richard Henderson &lt;rth@twiddle.net&gt;
Cc: Ivan Kokshaysky &lt;ink@jurassic.park.msu.ru&gt;
Cc: Matt Turner &lt;mattst88@gmail.com&gt;
Cc: Vineet Gupta &lt;vgupta@synopsys.com&gt;
Cc: Russell King &lt;rmk@arm.linux.org.uk&gt;
Cc: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Cc: Will Deacon &lt;will.deacon@arm.com&gt;
Cc: Haavard Skinnemoen &lt;hskinnemoen@gmail.com&gt;
Cc: Hans-Christian Egtvedt &lt;egtvedt@samfundet.no&gt;
Cc: Steven Miao &lt;realmz6@gmail.com&gt;
Cc: Mark Salter &lt;msalter@redhat.com&gt;
Cc: Aurelien Jacquiot &lt;a-jacquiot@ti.com&gt;
Cc: Mikael Starvik &lt;starvik@axis.com&gt;
Cc: Jesper Nilsson &lt;jesper.nilsson@axis.com&gt;
Cc: David Howells &lt;dhowells@redhat.com&gt;
Cc: Richard Kuo &lt;rkuo@codeaurora.org&gt;
Cc: "Luck, Tony" &lt;tony.luck@intel.com&gt;
Cc: Geert Uytterhoeven &lt;geert@linux-m68k.org&gt;
Cc: Michal Simek &lt;monstr@monstr.eu&gt;
Cc: Ralf Baechle &lt;ralf@linux-mips.org&gt;
Cc: Jonas Bonn &lt;jonas@southpole.se&gt;
Cc: "James E.J. Bottomley" &lt;jejb@parisc-linux.org&gt;
Cc: Helge Deller &lt;deller@gmx.de&gt;
Cc: Benjamin Herrenschmidt &lt;benh@kernel.crashing.org&gt;
Cc: Paul Mackerras &lt;paulus@samba.org&gt;
Acked-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt; (powerpc)
Tested-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt; (powerpc)
Cc: Martin Schwidefsky &lt;schwidefsky@de.ibm.com&gt;
Cc: Heiko Carstens &lt;heiko.carstens@de.ibm.com&gt;
Cc: Chen Liqin &lt;liqin.linux@gmail.com&gt;
Cc: Lennox Wu &lt;lennox.wu@gmail.com&gt;
Cc: Chris Metcalf &lt;cmetcalf@ezchip.com&gt;
Cc: Guan Xuetao &lt;gxt@mprc.pku.edu.cn&gt;
Cc: Chris Zankel &lt;chris@zankel.net&gt;
Cc: Max Filippov &lt;jcmvbkbc@gmail.com&gt;
Cc: Oleg Nesterov &lt;oleg@redhat.com&gt;
Cc: Guenter Roeck &lt;linux@roeck-us.net&gt;
Signed-off-by: James Hogan &lt;james.hogan@imgtec.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>mm: make FIRST_USER_ADDRESS unsigned long on all archs</title>
<updated>2015-02-12T01:06:03Z</updated>
<author>
<name>Kirill A. Shutemov</name>
<email>kirill.shutemov@linux.intel.com</email>
</author>
<published>2015-02-11T23:26:41Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=d016bf7ece53b2b947bfd769e0842fd2feb7556b'/>
<id>urn:sha1:d016bf7ece53b2b947bfd769e0842fd2feb7556b</id>
<content type='text'>
LKP has triggered a compiler warning after my recent patch "mm: account
pmd page tables to the process":

    mm/mmap.c: In function 'exit_mmap':
 &gt;&gt; mm/mmap.c:2857:2: warning: right shift count &gt;= width of type [enabled by default]

The code:

 &gt; 2857                WARN_ON(mm_nr_pmds(mm) &gt;
   2858                                round_up(FIRST_USER_ADDRESS, PUD_SIZE) &gt;&gt; PUD_SHIFT);

In this, on tile, we have FIRST_USER_ADDRESS defined as 0.  round_up() has
the same type -- int.  PUD_SHIFT.

I think the best way to fix it is to define FIRST_USER_ADDRESS as unsigned
long.  On every arch for consistency.

Signed-off-by: Kirill A. Shutemov &lt;kirill.shutemov@linux.intel.com&gt;
Reported-by: Wu Fengguang &lt;fengguang.wu@intel.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>mm/hugetlb: reduce arch dependent code around follow_huge_*</title>
<updated>2015-02-12T01:06:01Z</updated>
<author>
<name>Naoya Horiguchi</name>
<email>n-horiguchi@ah.jp.nec.com</email>
</author>
<published>2015-02-11T23:25:15Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=61f77eda9bbf0d2e922197ed2dcf88638a639ce5'/>
<id>urn:sha1:61f77eda9bbf0d2e922197ed2dcf88638a639ce5</id>
<content type='text'>
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 &lt;n-horiguchi@ah.jp.nec.com&gt;
Acked-by: Hugh Dickins &lt;hughd@google.com&gt;
Cc: James Hogan &lt;james.hogan@imgtec.com&gt;
Cc: David Rientjes &lt;rientjes@google.com&gt;
Cc: Mel Gorman &lt;mel@csn.ul.ie&gt;
Cc: Johannes Weiner &lt;hannes@cmpxchg.org&gt;
Cc: Michal Hocko &lt;mhocko@suse.cz&gt;
Cc: Rik van Riel &lt;riel@redhat.com&gt;
Cc: Andrea Arcangeli &lt;aarcange@redhat.com&gt;
Cc: Luiz Capitulino &lt;lcapitulino@redhat.com&gt;
Cc: Nishanth Aravamudan &lt;nacc@linux.vnet.ibm.com&gt;
Cc: Lee Schermerhorn &lt;lee.schermerhorn@hp.com&gt;
Cc: Steve Capper &lt;steve.capper@linaro.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>Merge branch 'akpm' (patches from Andrew)</title>
<updated>2015-02-11T00:45:56Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2015-02-11T00:45:56Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=992de5a8eca7cbd3215e3eb2c439b2c11582a58b'/>
<id>urn:sha1:992de5a8eca7cbd3215e3eb2c439b2c11582a58b</id>
<content type='text'>
Merge misc updates from Andrew Morton:
 "Bite-sized chunks this time, to avoid the MTA ratelimiting woes.

   - fs/notify updates

   - ocfs2

   - some of MM"

That laconic "some MM" is mainly the removal of remap_file_pages(),
which is a big simplification of the VM, and which gets rid of a *lot*
of random cruft and special cases because we no longer support the
non-linear mappings that it used.

From a user interface perspective, nothing has changed, because the
remap_file_pages() syscall still exists, it's just done by emulating the
old behavior by creating a lot of individual small mappings instead of
one non-linear one.

The emulation is slower than the old "native" non-linear mappings, but
nobody really uses or cares about remap_file_pages(), and simplifying
the VM is a big advantage.

* emailed patches from Andrew Morton &lt;akpm@linux-foundation.org&gt;: (78 commits)
  memcg: zap memcg_slab_caches and memcg_slab_mutex
  memcg: zap memcg_name argument of memcg_create_kmem_cache
  memcg: zap __memcg_{charge,uncharge}_slab
  mm/page_alloc.c: place zone_id check before VM_BUG_ON_PAGE check
  mm: hugetlb: fix type of hugetlb_treat_as_movable variable
  mm, hugetlb: remove unnecessary lower bound on sysctl handlers"?
  mm: memory: merge shared-writable dirtying branches in do_wp_page()
  mm: memory: remove -&gt;vm_file check on shared writable vmas
  xtensa: drop _PAGE_FILE and pte_file()-related helpers
  x86: drop _PAGE_FILE and pte_file()-related helpers
  unicore32: drop pte_file()-related helpers
  um: drop _PAGE_FILE and pte_file()-related helpers
  tile: drop pte_file()-related helpers
  sparc: drop pte_file()-related helpers
  sh: drop _PAGE_FILE and pte_file()-related helpers
  score: drop _PAGE_FILE and pte_file()-related helpers
  s390: drop pte_file()-related helpers
  parisc: drop _PAGE_FILE and pte_file()-related helpers
  openrisc: drop _PAGE_FILE and pte_file()-related helpers
  nios2: drop _PAGE_FILE and pte_file()-related helpers
  ...
</content>
</entry>
<entry>
<title>Merge tag 'pci-v3.20-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci</title>
<updated>2015-02-10T22:31:28Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2015-02-10T22:31:28Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=c08f8467939e7d2eebcba7cf2330242c4f53f2f7'/>
<id>urn:sha1:c08f8467939e7d2eebcba7cf2330242c4f53f2f7</id>
<content type='text'>
Pull PCI changes from Bjorn Helgaas:
 "Enumeration
    - Move domain assignment from arm64 to generic code (Lorenzo Pieralisi)
    - ARM: Remove artificial dependency on pci_sys_data domain (Lorenzo Pieralisi)
    - ARM: Move to generic PCI domains (Lorenzo Pieralisi)
    - Generate uppercase hex for modalias var in uevent (Ricardo Ribalda Delgado)
    - Add and use generic config accessors on ARM, PowerPC (Rob Herring)

  Resource management
    - Free resources on failure in of_pci_get_host_bridge_resources() (Lorenzo Pieralisi)
    - Fix infinite loop with ROM image of size 0 (Michel Dänzer)

  PCI device hotplug
    - Handle surprise add even if surprise removal isn't supported (Bjorn Helgaas)

  Virtualization
    - Mark AMD/ATI VGA devices that don't reset on D3hot-&gt;D0 transition (Alex Williamson)
    - Add DMA alias quirk for Adaptec 3405 (Alex Williamson)
    - Add Wellsburg (X99) to Intel PCH root port ACS quirk (Alex Williamson)
    - Add ACS quirk for Emulex NICs (Vasundhara Volam)

  MSI
    - Fail MSI-X mappings if there's no space assigned to MSI-X BAR (Yijing Wang)

  Freescale Layerscape host bridge driver
    - Fix platform_no_drv_owner.cocci warnings (Julia Lawall)

  NVIDIA Tegra host bridge driver
    - Remove unnecessary tegra_pcie_fixup_bridge() (Lucas Stach)

  Renesas R-Car host bridge driver
    - Fix error handling of irq_of_parse_and_map() (Dmitry Torokhov)

  TI Keystone host bridge driver
    - Fix error handling of irq_of_parse_and_map() (Dmitry Torokhov)
    - Fix misspelling of current function in debug output (Julia Lawall)

  Xilinx AXI host bridge driver
    - Fix harmless format string warning (Arnd Bergmann)

  Miscellaneous
    - Use standard parsing functions for ASPM sysfs setters (Chris J Arges)
    - Add pci_device_to_OF_node() stub for !CONFIG_OF (Kevin Hao)
    - Delete unnecessary NULL pointer checks (Markus Elfring)
    - Add and use defines for PCIe Max_Read_Request_Size (Rafał Miłecki)
    - Include clk.h instead of clk-private.h (Stephen Boyd)"

* tag 'pci-v3.20-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci: (48 commits)
  PCI: Add pci_device_to_OF_node() stub for !CONFIG_OF
  PCI: xilinx: Convert to use generic config accessors
  PCI: xgene: Convert to use generic config accessors
  PCI: tegra: Convert to use generic config accessors
  PCI: rcar: Convert to use generic config accessors
  PCI: generic: Convert to use generic config accessors
  powerpc/powermac: Convert PCI to use generic config accessors
  powerpc/fsl_pci: Convert PCI to use generic config accessors
  ARM: ks8695: Convert PCI to use generic config accessors
  ARM: sa1100: Convert PCI to use generic config accessors
  ARM: integrator: Convert PCI to use generic config accessors
  PCI: versatile: Add DT-based ARM Versatile PB PCIe host driver
  ARM: dts: versatile: add PCI controller binding
  of/pci: Free resources on failure in of_pci_get_host_bridge_resources()
  PCI: versatile: Add DT docs for ARM Versatile PB PCIe driver
  PCI: Fail MSI-X mappings if there's no space assigned to MSI-X BAR
  r8169: use PCI define for Max_Read_Request_Size
  [SCSI] esas2r: use PCI define for Max_Read_Request_Size
  tile: use PCI define for Max_Read_Request_Size
  rapidio/tsi721: use PCI define for Max_Read_Request_Size
  ...
</content>
</entry>
<entry>
<title>tile: drop pte_file()-related helpers</title>
<updated>2015-02-10T22:30:33Z</updated>
<author>
<name>Kirill A. Shutemov</name>
<email>kirill.shutemov@linux.intel.com</email>
</author>
<published>2015-02-10T22:11:14Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=eb12f4872a3845a8803f689646dea5b92a30aff7'/>
<id>urn:sha1:eb12f4872a3845a8803f689646dea5b92a30aff7</id>
<content type='text'>
We've replaced remap_file_pages(2) implementation with emulation.  Nobody
creates non-linear mapping anymore.

Signed-off-by: Kirill A. Shutemov &lt;kirill.shutemov@linux.intel.com&gt;
Acked-by: Chris Metcalf &lt;cmetcalf@ezchip.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip</title>
<updated>2015-02-09T22:28:42Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2015-02-09T22:28:42Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=23e8fe2e16587494268510c1bc9f6952f50f0311'/>
<id>urn:sha1:23e8fe2e16587494268510c1bc9f6952f50f0311</id>
<content type='text'>
Pull RCU updates from Ingo Molnar:
 "The main RCU changes in this cycle are:

   - Documentation updates.

   - Miscellaneous fixes.

   - Preemptible-RCU fixes, including fixing an old bug in the
     interaction of RCU priority boosting and CPU hotplug.

   - SRCU updates.

   - RCU CPU stall-warning updates.

   - RCU torture-test updates"

* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (54 commits)
  rcu: Initialize tiny RCU stall-warning timeouts at boot
  rcu: Fix RCU CPU stall detection in tiny implementation
  rcu: Add GP-kthread-starvation checks to CPU stall warnings
  rcu: Make cond_resched_rcu_qs() apply to normal RCU flavors
  rcu: Optionally run grace-period kthreads at real-time priority
  ksoftirqd: Use new cond_resched_rcu_qs() function
  ksoftirqd: Enable IRQs and call cond_resched() before poking RCU
  rcutorture: Add more diagnostics in rcu_barrier() test failure case
  torture: Flag console.log file to prevent holdovers from earlier runs
  torture: Add "-enable-kvm -soundhw pcspk" to qemu command line
  rcutorture: Handle different mpstat versions
  rcutorture: Check from beginning to end of grace period
  rcu: Remove redundant rcu_batches_completed() declaration
  rcutorture: Drop rcu_torture_completed() and friends
  rcu: Provide rcu_batches_completed_sched() for TINY_RCU
  rcutorture: Use unsigned for Reader Batch computations
  rcutorture: Make build-output parsing correctly flag RCU's warnings
  rcu: Make _batches_completed() functions return unsigned long
  rcutorture: Issue warnings on close calls due to Reader Batch blows
  documentation: Fix smp typo in memory-barriers.txt
  ...
</content>
</entry>
<entry>
<title>vm: add VM_FAULT_SIGSEGV handling support</title>
<updated>2015-01-29T18:51:32Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2015-01-29T18:51:32Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=33692f27597fcab536d7cbbcc8f52905133e4aa7'/>
<id>urn:sha1:33692f27597fcab536d7cbbcc8f52905133e4aa7</id>
<content type='text'>
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 &lt;tiwai@suse.de&gt;
Tested-by: Jan Engelhardt &lt;jengelh@inai.de&gt;
Acked-by: Heiko Carstens &lt;heiko.carstens@de.ibm.com&gt; # "s390 still compiles and boots"
Cc: linux-arch@vger.kernel.org
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
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