commit 33692f27597fcab536d7cbbcc8f52905133e4aa7 upstream.

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 <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
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[bwh: Backported to 3.2:
 - Adjust filenames, context
 - Drop arc, metag, nios2 and lustre changes
 - For sh, patch both 32-bit and 64-bit implementations to use goto bad_area
 - For s390, pass int_code and trans_exc_code as arguments to do_no_context()
   and do_sigsegv()]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit abdf8b5e07884a183938969253770164d60b87cb upstream.

Use of EXPORT_SYMBOL requires inclusion of export.h

Signed-off-by: Jonas Bonn <jonas@southpole.se>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 160d83781a32e94a1e337efd6722939001e62398 upstream.

Prevents build issue with updated toolchain

Reported-by: Jack Thomasson <jkt@moonlitsw.com>
Tested-by: Christian Svensson <blue@cmd.nu>
Signed-off-by: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Signed-off-by: Jonas Bonn <jonas@southpole.se>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

* 'trivial' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild:
  scsi: drop unused Kconfig symbol
  pci: drop unused Kconfig symbol
  stmmac: drop unused Kconfig symbol
  x86: drop unused Kconfig symbol
  powerpc: drop unused Kconfig symbols
  powerpc: 40x: drop unused Kconfig symbol
  mips: drop unused Kconfig symbols
  openrisc: drop unused Kconfig symbols
  arm: at91: drop unused Kconfig symbol
  samples: drop unused Kconfig symbol
  m32r: drop unused Kconfig symbol
  score: drop unused Kconfig symbols
  sh: drop unused Kconfig symbol
  um: drop unused Kconfig symbol
  sparc: drop unused Kconfig symbol
  alpha: drop unused Kconfig symbol

Fix up trivial conflict in drivers/net/ethernet/stmicro/stmmac/Kconfig
as per Michal: the STMMAC_DUAL_MAC config variable is still unused and
should be deleted.

Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Michal Marek <mmarek@suse.cz>

There are numerous broken references to Documentation files (in other
Documentation files, in comments, etc.). These broken references are
caused by typo's in the references, and by renames or removals of the
Documentation files. Some broken references are simply odd.

Fix these broken references, sometimes by dropping the irrelevant text
they were part of.

Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

For the initial architecture submission, not all of the DMA ops were
implemented.  This patch adds the *map_page and *map_sg variants of the
DMA mapping ops.

This patch is currently of interest mainly to some drivers that haven't
been submitted upstream yet.

Signed-off-by: Jonas Bonn <jonas@southpole.se>

As it was decided not to export struct pt_regs to userspace, struct
sigcontext shouldn't be using it either.  The pt_regs struct for OpenRISC
is kernel internal and the layout of the registers may change in the
future.  The struct user_regs_struct is what is guaranteed to remain
stable, so struct sigcontext may use that instead.

This patch removes the usage of struct pt_regs in struct sigcontext and
makes according changes in signal.c to get the register layout right.

The usp field is removed from the sigcontext structure as this information
is already contained in the user_regs_struct.

Signed-off-by: Jonas Bonn <jonas@southpole.se>
Reviewed-by: Emilio Cota <cota@braap.org>

Adds README file, TODO list, and a couple of other pieces that didn't seem
to fit into any other patch.

Signed-off-by: Jonas Bonn <jonas@southpole.se>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>

Signed-off-by: Jonas Bonn <jonas@southpole.se>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>