commit d71f290b4e98a39f49f2595a13be3b4d5ce8e1f1 upstream.

Specify the maximum stack size for arches where the stack grows upward
(parisc and metag) in asm/processor.h rather than hard coding in
fs/exec.c so that metag can specify a smaller value of 256MB rather than
1GB.

This fixes a BUG on metag if the RLIMIT_STACK hard limit is increased
beyond a safe value by root. E.g. when starting a process after running
"ulimit -H -s unlimited" it will then attempt to use a stack size of the
maximum 1GB which is far too big for metag's limited user virtual
address space (stack_top is usually 0x3ffff000):

BUG: failure at fs/exec.c:589/shift_arg_pages()!

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Helge Deller <deller@gmx.de>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: linux-parisc@vger.kernel.org
Cc: linux-metag@vger.kernel.org
Cc: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit c776cd89fc705fc8b5c2e5ad906bf5d791620fed upstream.

The attached change significantly improves the performance of the LWS-CAS code
in syscall.S.
This allows a number of packages to build (e.g., zeromq3, gtest and libxs)
that previously failed because slow LWS-CAS performance under contention. In
particular, interrupts taken while the lock was taken degraded performance
significantly.

The change does the following:

1) Disables interrupts around the CAS operation, and
2) Changes the loads and stores to use the ordered completer, "o", on
PA 2.0. "o" and "ma" with a zero offset are equivalent. The latter is
accepted on both PA 1.X and 2.0.

The use of ordered loads and stores probably makes no difference on all
existing hardware, but it seemed pedantically correct. In particular, the CAS
operation must complete before LDCW lock is released. As written before, a
processor could reorder the operations.

I don't believe the period interrupts are disabled is long enough to
significantly increase interrupt latency. For example, the TLB insert code is
longer. Worst case is a memory fault in the CAS operation.

Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit fef47e2a2e1e75fe50a10f634a80f16808348cc6 upstream.

Ratelimit printing of userspace segfaults and make it runtime
configurable via the /proc/sys/debug/exception-trace variable. This
should resolve syslog from growing way too fast and thus prevents
possible system service attacks.

Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit e0d8898d76a785453bfaf6cd08b830a7d5189f78 upstream.

There are only a couple of architectures that override _STK_LIM_MAX to
a non-infinity value. This changes the stack allocation semantics in
subtle ways. For example, GNU make changes its stack allocation to the
hard maximum defined by _STK_LIM_MAX. As a results, threads executed
by processes running under make are allocated a stack size of
_STK_LIM_MAX rather than a sensible default value. This causes various
thread stress tests to fail when they can't muster more than about 50
threads.

The attached change implements the default behavior used by the
majority of architectures.

Signed-off-by: John David Anglin <dave.anglin@bell.net>
Reviewed-by: Carlos O'Donell <carlos@systemhalted.org>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit ab3e55b119c9653b19ea4edffb86f04db867ac98 upstream.

This bug was detected with the libio-epoll-perl debian package where the
test case IO-Ppoll-compat.t failed.

Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit 0ef36bd2b37815719e31a72d2beecc28ca8ecd26 upstream.

On parisc, SHMLBA was defined to 0x00400000 (4MB) to reflect that we need to
take care of our caches for shared mappings. But actually, we can map a file at
any multiple address of PAGE_SIZE, so let us correct that now with a value of
PAGE_SIZE for SHMLBA.  Instead we now take care of this cache colouring via the
constant SHM_COLOUR while we map shared pages.

Signed-off-by: Helge Deller <deller@gmx.de>
CC: Jeroen Roovers <jer@gentoo.org>
CC: John David Anglin <dave.anglin@bell.net>
CC: Carlos O'Donell <carlos@systemhalted.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Now that the arch_{spin,read,write}_relax macros default to cpu_relax(),
remove the redundant definitions for parisc.

Cc: Helge Deller <deller@gmx.de>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Helge Deller <deller@gmx.de>

We seem to be nearly the only platform which does not provide the
sys_utimes syscall.  Adding it now makes our life much easier with
userspace applications (like dietlibc and e2fsprogs) since we then
behave like all other platforms too and don't need extra patches which
are hard to get upstream anyway because we are not a mainstream
architecture.

Signed-off-by: Helge Deller <deller@gmx.de>
Cc: stable@vger.kernel.org # v3.13

The attached change removes the unused and experimental
CONFIG_PARISC_TMPALIAS code. It doesn't work and I don't believe it will
ever be used.

Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>

This changes 'do_execve()' to get the executable name as a 'struct
filename', and to free it when it is done.  This is what the normal
users want, and it simplifies and streamlines their error handling.

The controlled lifetime of the executable name also fixes a
use-after-free problem with the trace_sched_process_exec tracepoint: the
lifetime of the passed-in string for kernel users was not at all
obvious, and the user-mode helper code used UMH_WAIT_EXEC to serialize
the pathname allocation lifetime with the execve() having finished,
which in turn meant that the trace point that happened after
mm_release() of the old process VM ended up using already free'd memory.

To solve the kernel string lifetime issue, this simply introduces
"getname_kernel()" that works like the normal user-space getname()
function, except with the source coming from kernel memory.

As Oleg points out, this also means that we could drop the tcomm[] array
from 'struct linux_binprm', since the pathname lifetime now covers
setup_new_exec().  That would be a separate cleanup.

Reported-by: Igor Zhbanov <i.zhbanov@samsung.com>
Tested-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>