linux-toradex.git/arch/tile/Kconfig, branch v4.10

atomic64: no need for CONFIG_ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE

2016-10-08T01:46:30+00:00

This came to light when implementing native 64-bit atomics for ARCv2.

The atomic64 self-test code uses CONFIG_ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
to check whether atomic64_dec_if_positive() is available.  It seems it
was needed when not every arch defined it.  However as of current code
the Kconfig option seems needless

 - for CONFIG_GENERIC_ATOMIC64 it is auto-enabled in lib/Kconfig and a
   generic definition of API is present lib/atomic64.c
 - arches with native 64-bit atomics select it in arch/*/Kconfig and
   define the API in their headers

So I see no point in keeping the Kconfig option

Compile tested for:
 - blackfin (CONFIG_GENERIC_ATOMIC64)
 - x86 (!CONFIG_GENERIC_ATOMIC64)
 - ia64

Link: http://lkml.kernel.org/r/1473703083-8625-3-git-send-email-vgupta@synopsys.com
Signed-off-by: Vineet Gupta 
Cc: Richard Henderson 
Cc: Ivan Kokshaysky 
Cc: Matt Turner 
Cc: Russell King 
Cc: Catalin Marinas 
Cc: Will Deacon 
Cc: Ralf Baechle 
Cc: "James E.J. Bottomley" 
Cc: Helge Deller 
Cc: Benjamin Herrenschmidt 
Cc: Paul Mackerras 
Cc: Michael Ellerman 
Cc: Martin Schwidefsky 
Cc: Heiko Carstens 
Cc: "David S. Miller" 
Cc: Chris Metcalf 
Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Cc: "H. Peter Anvin" 
Cc: Vineet Gupta 
Cc: Zhaoxiu Zeng 
Cc: Linus Walleij 
Cc: Alexander Potapenko 
Cc: Andrey Ryabinin 
Cc: Herbert Xu 
Cc: Ming Lin 
Cc: Arnd Bergmann 
Cc: Geert Uytterhoeven 
Cc: Peter Zijlstra 
Cc: Borislav Petkov 
Cc: Andi Kleen 
Cc: Boqun Feng 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/usercopy: get rid of CONFIG_DEBUG_STRICT_USER_COPY_CHECKS

2016-08-30T17:10:21+00:00

There are three usercopy warnings which are currently being silenced for
gcc 4.6 and newer:

1) "copy_from_user() buffer size is too small" compile warning/error

   This is a static warning which happens when object size and copy size
   are both const, and copy size > object size.  I didn't see any false
   positives for this one.  So the function warning attribute seems to
   be working fine here.

   Note this scenario is always a bug and so I think it should be
   changed to *always* be an error, regardless of
   CONFIG_DEBUG_STRICT_USER_COPY_CHECKS.

2) "copy_from_user() buffer size is not provably correct" compile warning

   This is another static warning which happens when I enable
   __compiletime_object_size() for new compilers (and
   CONFIG_DEBUG_STRICT_USER_COPY_CHECKS).  It happens when object size
   is const, but copy size is *not*.  In this case there's no way to
   compare the two at build time, so it gives the warning.  (Note the
   warning is a byproduct of the fact that gcc has no way of knowing
   whether the overflow function will be called, so the call isn't dead
   code and the warning attribute is activated.)

   So this warning seems to only indicate "this is an unusual pattern,
   maybe you should check it out" rather than "this is a bug".

   I get 102(!) of these warnings with allyesconfig and the
   __compiletime_object_size() gcc check removed.  I don't know if there
   are any real bugs hiding in there, but from looking at a small
   sample, I didn't see any.  According to Kees, it does sometimes find
   real bugs.  But the false positive rate seems high.

3) "Buffer overflow detected" runtime warning

   This is a runtime warning where object size is const, and copy size >
   object size.

All three warnings (both static and runtime) were completely disabled
for gcc 4.6 with the following commit:

  2fb0815c9ee6 ("gcc4: disable __compiletime_object_size for GCC 4.6+")

That commit mistakenly assumed that the false positives were caused by a
gcc bug in __compiletime_object_size().  But in fact,
__compiletime_object_size() seems to be working fine.  The false
positives were instead triggered by #2 above.  (Though I don't have an
explanation for why the warnings supposedly only started showing up in
gcc 4.6.)

So remove warning #2 to get rid of all the false positives, and re-enable
warnings #1 and #3 by reverting the above commit.

Furthermore, since #1 is a real bug which is detected at compile time,
upgrade it to always be an error.

Having done all that, CONFIG_DEBUG_STRICT_USER_COPY_CHECKS is no longer
needed.

Signed-off-by: Josh Poimboeuf 
Cc: Kees Cook 
Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Cc: "H . Peter Anvin" 
Cc: Andy Lutomirski 
Cc: Steven Rostedt 
Cc: Brian Gerst 
Cc: Peter Zijlstra 
Cc: Frederic Weisbecker 
Cc: Byungchul Park 
Cc: Nilay Vaish 
Signed-off-by: Linus Torvalds

Merge git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile

2016-05-24T02:05:11+00:00

Pull arch/tile updates from Chris Metcalf:
 "This is an even quieter cycle than usual"

* git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile:
  Fix typo
  Fix typo
  Fix typo
  tile: sort the "select" lines in the TILE/TILEGX configs
  tile: clarify barrier semantics of atomic_add_return
  tile/defconfigs: Remove CONFIG_IPV6_PRIVACY

printk/nmi: generic solution for safe printk in NMI

2016-05-21T00:58:30+00:00

printk() takes some locks and could not be used a safe way in NMI
context.

The chance of a deadlock is real especially when printing stacks from
all CPUs.  This particular problem has been addressed on x86 by the
commit a9edc8809328 ("x86/nmi: Perform a safe NMI stack trace on all
CPUs").

The patchset brings two big advantages.  First, it makes the NMI
backtraces safe on all architectures for free.  Second, it makes all NMI
messages almost safe on all architectures (the temporary buffer is
limited.  We still should keep the number of messages in NMI context at
minimum).

Note that there already are several messages printed in NMI context:
WARN_ON(in_nmi()), BUG_ON(in_nmi()), anything being printed out from MCE
handlers.  These are not easy to avoid.

This patch reuses most of the code and makes it generic.  It is useful
for all messages and architectures that support NMI.

The alternative printk_func is set when entering and is reseted when
leaving NMI context.  It queues IRQ work to copy the messages into the
main ring buffer in a safe context.

__printk_nmi_flush() copies all available messages and reset the buffer.
Then we could use a simple cmpxchg operations to get synchronized with
writers.  There is also used a spinlock to get synchronized with other
flushers.

We do not longer use seq_buf because it depends on external lock.  It
would be hard to make all supported operations safe for a lockless use.
It would be confusing and error prone to make only some operations safe.

The code is put into separate printk/nmi.c as suggested by Steven
Rostedt.  It needs a per-CPU buffer and is compiled only on
architectures that call nmi_enter().  This is achieved by the new
HAVE_NMI Kconfig flag.

The are MN10300 and Xtensa architectures.  We need to clean up NMI
handling there first.  Let's do it separately.

The patch is heavily based on the draft from Peter Zijlstra, see

  https://lkml.org/lkml/2015/6/10/327

[arnd@arndb.de: printk-nmi: use %zu format string for size_t]
[akpm@linux-foundation.org: min_t->min - all types are size_t here]
Signed-off-by: Petr Mladek 
Suggested-by: Peter Zijlstra 
Suggested-by: Steven Rostedt 
Cc: Jan Kara 
Acked-by: Russell King 	[arm part]
Cc: Daniel Thompson 
Cc: Jiri Kosina 
Cc: Ingo Molnar 
Cc: Thomas Gleixner 
Cc: Ralf Baechle 
Cc: Benjamin Herrenschmidt 
Cc: Martin Schwidefsky 
Cc: David Miller 
Cc: Daniel Thompson 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

exit_thread: remove empty bodies

2016-05-21T00:58:30+00:00

Define HAVE_EXIT_THREAD for archs which want to do something in
exit_thread. For others, let's define exit_thread as an empty inline.

This is a cleanup before we change the prototype of exit_thread to
accept a task parameter.

[akpm@linux-foundation.org: fix mips]
Signed-off-by: Jiri Slaby 
Cc: "David S. Miller" 
Cc: "H. Peter Anvin" 
Cc: "James E.J. Bottomley" 
Cc: Aurelien Jacquiot 
Cc: Benjamin Herrenschmidt 
Cc: Catalin Marinas 
Cc: Chen Liqin 
Cc: Chris Metcalf 
Cc: Chris Zankel 
Cc: David Howells 
Cc: Fenghua Yu 
Cc: Geert Uytterhoeven 
Cc: Guan Xuetao 
Cc: Haavard Skinnemoen 
Cc: Hans-Christian Egtvedt 
Cc: Heiko Carstens 
Cc: Helge Deller 
Cc: Ingo Molnar 
Cc: Ivan Kokshaysky 
Cc: James Hogan 
Cc: Jeff Dike 
Cc: Jesper Nilsson 
Cc: Jiri Slaby 
Cc: Jonas Bonn 
Cc: Koichi Yasutake 
Cc: Lennox Wu 
Cc: Ley Foon Tan 
Cc: Mark Salter 
Cc: Martin Schwidefsky 
Cc: Matt Turner 
Cc: Max Filippov 
Cc: Michael Ellerman 
Cc: Michal Simek 
Cc: Mikael Starvik 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Cc: Ralf Baechle 
Cc: Rich Felker 
Cc: Richard Henderson 
Cc: Richard Kuo 
Cc: Richard Weinberger 
Cc: Russell King 
Cc: Steven Miao 
Cc: Thomas Gleixner 
Cc: Tony Luck 
Cc: Vineet Gupta 
Cc: Will Deacon 
Cc: Yoshinori Sato 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

tile: sort the "select" lines in the TILE/TILEGX configs

2016-04-28T14:19:41+00:00

Also remove the stale "FIXME: investigate these options" language.

Signed-off-by: Chris Metcalf

PCI: Include pci/hotplug Kconfig directly from pci/Kconfig

2016-03-08T21:10:48+00:00

Include pci/hotplug/Kconfig directly from pci/Kconfig, so arches don't
have to source both pci/Kconfig and pci/hotplug/Kconfig.

Note that this effectively adds pci/hotplug/Kconfig to the following
arches, because they already sourced drivers/pci/Kconfig but they
previously did not source drivers/pci/hotplug/Kconfig:

  alpha
  arm
  avr32
  frv
  m68k
  microblaze
  mn10300
  sparc
  unicore32

Inspired-by-patch-from: Bogicevic Sasa 
Signed-off-by: Bjorn Helgaas

PCI: Include pci/pcie/Kconfig directly from pci/Kconfig

2016-03-08T20:36:48+00:00

Include pci/pcie/Kconfig directly from pci/Kconfig, so arches don't
have to source both pci/Kconfig and pci/pcie/Kconfig.

Note that this effectively adds pci/pcie/Kconfig to the following
arches, because they already sourced drivers/pci/Kconfig but they
previously did not source drivers/pci/pcie/Kconfig:

  alpha
  avr32
  blackfin
  frv
  m32r
  m68k
  microblaze
  mn10300
  parisc
  sparc
  unicore32
  xtensa

[bhelgaas: changelog, source pci/pcie/Kconfig at top of pci/Kconfig, whitespace]
Signed-off-by: Sasa Bogicevic 
Signed-off-by: Bjorn Helgaas

dma-mapping: always provide the dma_map_ops based implementation

2016-01-21T01:09:18+00:00

Move the generic implementation to  now that all
architectures support it and remove the HAVE_DMA_ATTR Kconfig symbol now
that everyone supports them.

[valentinrothberg@gmail.com: remove leftovers in Kconfig]
Signed-off-by: Christoph Hellwig 
Cc: "David S. Miller" 
Cc: Aurelien Jacquiot 
Cc: Chris Metcalf 
Cc: David Howells 
Cc: Geert Uytterhoeven 
Cc: Haavard Skinnemoen 
Cc: Hans-Christian Egtvedt 
Cc: Helge Deller 
Cc: James Hogan 
Cc: Jesper Nilsson 
Cc: Koichi Yasutake 
Cc: Ley Foon Tan 
Cc: Mark Salter 
Cc: Mikael Starvik 
Cc: Steven Miao 
Cc: Vineet Gupta 
Cc: Christian Borntraeger 
Cc: Joerg Roedel 
Cc: Sebastian Ott 
Signed-off-by: Valentin Rothberg 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile

2016-01-18T20:57:18+00:00

Pull arch/tile updates from Chris Metcalf:
 "This is a grab bag of changes that includes some NOHZ and
  context-tracking related changes, some debugging improvements,
  JUMP_LABEL support, and some fixes for tilepro allmodconfig support.

  We also remove the now-unused node_has_online_mem() definitions both
  for tile's asm/topology.h as well as in linux/topology.h itself"

* git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile:
  numa: remove stale node_has_online_mem() define
  arch/tile: move user_exit() to early kernel entry sequence
  tile: fix bug in setting PT_FLAGS_DISABLE_IRQ on kernel entry
  tile: fix tilepro casts for readl, writel, etc
  tile: fix a -Wframe-larger-than warning
  tile: include the syscall number in the backtrace
  MAINTAINERS: add git URL for tile
  arch/tile: adopt prepare_exit_to_usermode() model from x86
  tile/jump_label: add jump label support for TILE-Gx
  tile: define a macro ktext_writable_addr to get writable kernel text address