linux-stable.git/arch/sh, branch v4.0

Merge tag 'asm-generic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic

2015-02-18T18:02:24+00:00

Pull asm-generic uaccess.h cleanup from Arnd Bergmann:
 "Like in 3.19, I once more have a multi-stage cleanup for one
  asm-generic header file, this time the work was done by Michael
  Tsirkin and cleans up the uaccess.h file in asm-generic, as well as
  all architectures for which the respective maintainers did not pick up
  his patches directly"

* tag 'asm-generic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic: (37 commits)
  sparc32: nocheck uaccess coding style tweaks
  sparc64: nocheck uaccess coding style tweaks
  xtensa: macro whitespace fixes
  sh: macro whitespace fixes
  parisc: macro whitespace fixes
  m68k: macro whitespace fixes
  m32r: macro whitespace fixes
  frv: macro whitespace fixes
  cris: macro whitespace fixes
  avr32: macro whitespace fixes
  arm64: macro whitespace fixes
  arm: macro whitespace fixes
  alpha: macro whitespace fixes
  blackfin: macro whitespace fixes
  sparc64: uaccess_64 macro whitespace fixes
  sparc32: uaccess_32 macro whitespace fixes
  avr32: whitespace fix
  sh: fix put_user sparse errors
  metag: fix put_user sparse errors
  ia64: fix put_user sparse errors
  ...

Merge tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/borntraeger/linux

2015-02-14T18:54:28+00:00

Pull ACCESS_ONCE() rule tightening from Christian Borntraeger:
 "Tighten rules for ACCESS_ONCE

  This series tightens the rules for ACCESS_ONCE to only work on scalar
  types.  It also contains the necessary fixups as indicated by build
  bots of linux-next.  Now everything is in place to prevent new
  non-scalar users of ACCESS_ONCE and we can continue to convert code to
  READ_ONCE/WRITE_ONCE"

* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/borntraeger/linux:
  kernel: Fix sparse warning for ACCESS_ONCE
  next: sh: Fix compile error
  kernel: tighten rules for ACCESS ONCE
  mm/gup: Replace ACCESS_ONCE with READ_ONCE
  x86/spinlock: Leftover conversion ACCESS_ONCE->READ_ONCE
  x86/xen/p2m: Replace ACCESS_ONCE with READ_ONCE
  ppc/hugetlbfs: Replace ACCESS_ONCE with READ_ONCE
  ppc/kvm: Replace ACCESS_ONCE with READ_ONCE

all arches, signal: move restart_block to struct task_struct

2015-02-13T02:54:12+00:00

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 
Cc: Thomas Gleixner 
Cc: Al Viro 
Cc: "H. Peter Anvin" 
Cc: Ingo Molnar 
Cc: Kees Cook 
Cc: David Miller 
Acked-by: Richard Weinberger 
Cc: Richard Henderson 
Cc: Ivan Kokshaysky 
Cc: Matt Turner 
Cc: Vineet Gupta 
Cc: Russell King 
Cc: Catalin Marinas 
Cc: Will Deacon 
Cc: Haavard Skinnemoen 
Cc: Hans-Christian Egtvedt 
Cc: Steven Miao 
Cc: Mark Salter 
Cc: Aurelien Jacquiot 
Cc: Mikael Starvik 
Cc: Jesper Nilsson 
Cc: David Howells 
Cc: Richard Kuo 
Cc: "Luck, Tony" 
Cc: Geert Uytterhoeven 
Cc: Michal Simek 
Cc: Ralf Baechle 
Cc: Jonas Bonn 
Cc: "James E.J. Bottomley" 
Cc: Helge Deller 
Cc: Benjamin Herrenschmidt 
Cc: Paul Mackerras 
Acked-by: Michael Ellerman  (powerpc)
Tested-by: Michael Ellerman  (powerpc)
Cc: Martin Schwidefsky 
Cc: Heiko Carstens 
Cc: Chen Liqin 
Cc: Lennox Wu 
Cc: Chris Metcalf 
Cc: Guan Xuetao 
Cc: Chris Zankel 
Cc: Max Filippov 
Cc: Oleg Nesterov 
Cc: Guenter Roeck 
Signed-off-by: James Hogan 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: gup: use get_user_pages_unlocked within get_user_pages_fast

2015-02-12T01:06:05+00:00

This allows the get_user_pages_fast slow path to release the mmap_sem
before blocking.

Signed-off-by: Andrea Arcangeli 
Reviewed-by: Kirill A. Shutemov 
Cc: Andres Lagar-Cavilla 
Cc: Peter Feiner 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: make FIRST_USER_ADDRESS unsigned long on all archs

2015-02-12T01:06:03+00:00

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':
 >> mm/mmap.c:2857:2: warning: right shift count >= width of type [enabled by default]

The code:

 > 2857                WARN_ON(mm_nr_pmds(mm) >
   2858                                round_up(FIRST_USER_ADDRESS, PUD_SIZE) >> 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 
Reported-by: Wu Fengguang 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/hugetlb: reduce arch dependent code around follow_huge_*

2015-02-12T01:06:01+00:00

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 
Acked-by: Hugh Dickins 
Cc: James Hogan 
Cc: David Rientjes 
Cc: Mel Gorman 
Cc: Johannes Weiner 
Cc: Michal Hocko 
Cc: Rik van Riel 
Cc: Andrea Arcangeli 
Cc: Luiz Capitulino 
Cc: Nishanth Aravamudan 
Cc: Lee Schermerhorn 
Cc: Steve Capper 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

sh: drop _PAGE_FILE and pte_file()-related helpers

2015-02-10T22:30:33+00:00

We've replaced remap_file_pages(2) implementation with emulation.  Nobody
creates non-linear mapping anymore.

Signed-off-by: Kirill A. Shutemov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

sh: eliminate unused irq_reg_{readl,writel} accessors

2015-02-10T22:30:28+00:00

Defining these macros way down in arch/sh/.../irq.c doesn't cause
kernel/irq/generic-chip.c to use them.  As far as I can tell this code has
no effect.

Fixes: 332fd7c4fef5f3b1 ("genirq: Generic chip: Change irq_reg_{readl,writel} arguments")
Signed-off-by: Kevin Cernekee 
Signed-off-by: Geert Uytterhoeven 
Tested-by: Geert Uytterhoeven  (cpp/asm comparison)
Cc: Thomas Gleixner 
Cc: Jason Cooper 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

sh: build superh without CONFIG_EXPERT

2015-02-10T22:30:28+00:00

What sh4 actually wants is HAVE_PATA_PLATFORM, so select that instead.

Signed-off-by: Rob Landley 
Acked-by: Randy Dunlap 
Acked-by: Geert Uytterhoeven 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

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