Pull ARM fixes from Russell King:
 "A number of fixes for the merge window, fixing a number of cases
  missed when testing the uaccess code, particularly cases which only
  show up with certain compiler versions"

* 'fixes' of git://ftp.arm.linux.org.uk/~rmk/linux-arm:
  ARM: 8431/1: fix alignement of __bug_table section entries
  arm/xen: Enable user access to the kernel before issuing a privcmd call
  ARM: domains: add memory dependencies to get_domain/set_domain
  ARM: domains: thread_info.h no longer needs asm/domains.h
  ARM: uaccess: fix undefined instruction on ARMv7M/noMMU
  ARM: uaccess: remove unneeded uaccess_save_and_disable macro
  ARM: swpan: fix nwfpe for uaccess changes
  ARM: 8429/1: disable GCC SRA optimization

This macro is never referenced, remove it.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Provide a software-based implementation of the priviledged no access
support found in ARMv8.1.

Userspace pages are mapped using a different domain number from the
kernel and IO mappings.  If we switch the user domain to "no access"
when we enter the kernel, we can prevent the kernel from touching
userspace.

However, the kernel needs to be able to access userspace via the
various user accessor functions.  With the wrapping in the previous
patch, we can temporarily enable access when the kernel needs user
access, and re-disable it afterwards.

This allows us to trap non-intended accesses to userspace, eg, caused
by an inadvertent dereference of the LIST_POISON* values, which, with
appropriate user mappings setup, can be made to succeed.  This in turn
can allow use-after-free bugs to be further exploited than would
otherwise be possible.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Provide hooks into the kernel entry and exit paths to permit control
of userspace visibility to the kernel.  The intended use is:

- on entry to kernel from user, uaccess_disable will be called to
  disable userspace visibility
- on exit from kernel to user, uaccess_enable will be called to
  enable userspace visibility
- on entry from a kernel exception, uaccess_save_and_disable will be
  called to save the current userspace visibility setting, and disable
  access
- on exit from a kernel exception, uaccess_restore will be called to
  restore the userspace visibility as it was before the exception
  occurred.

These hooks allows us to keep userspace visibility disabled for the
vast majority of the kernel, except for localised regions where we
want to explicitly access userspace.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Make the "fast" syscall return path fast again.  The addition of IRQ
tracing and context tracking has made this path grossly inefficient.
We can do much better if these options are enabled if we save the
syscall return code on the stack - we then don't need to save a bunch
of registers around every single callout to C code.

Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

There's no need for this macro, it can use a default for the
condition argument.

Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

BSYM() was invented to allow us to work around a problem with the
assembler, where local symbols resolved by the assembler for the 'adr'
instruction did not take account of their ISA.

Since we don't want BSYM() used elsewhere, replace BSYM() with a new
macro 'badr', which is like the 'adr' pseudo-op, but with the BSYM()
mechanics integrated into it.  This ensures that the BSYM()-ification
is only used in conjunction with 'adr'.

Acked-by: Dave Martin <Dave.Martin@arm.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Allow ALT_UP() to cope with a 16-bit Thumb instruction by automatically
inserting a following nop instruction.  This allows us to care less
about getting the assembler to emit a 32-bit thumb instruction.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

ARMv6 and greater introduced a new instruction ("bx") which can be used
to return from function calls.  Recent CPUs perform better when the
"bx lr" instruction is used rather than the "mov pc, lr" instruction,
and this sequence is strongly recommended to be used by the ARM
architecture manual (section A.4.1.1).

We provide a new macro "ret" with all its variants for the condition
code which will resolve to the appropriate instruction.

Rather than doing this piecemeal, and miss some instances, change all
the "mov pc" instances to use the new macro, with the exception of
the "movs" instruction and the kprobes code.  This allows us to detect
the "mov pc, lr" case and fix it up - and also gives us the possibility
of deploying this for other registers depending on the CPU selection.

Reported-by: Will Deacon <will.deacon@arm.com>
Tested-by: Stephen Warren <swarren@nvidia.com> # Tegra Jetson TK1
Tested-by: Robert Jarzmik <robert.jarzmik@free.fr> # mioa701_bootresume.S
Tested-by: Andrew Lunn <andrew@lunn.ch> # Kirkwood
Tested-by: Shawn Guo <shawn.guo@freescale.com>
Tested-by: Tony Lindgren <tony@atomide.com> # OMAPs
Tested-by: Gregory CLEMENT <gregory.clement@free-electrons.com> # Armada XP, 375, 385
Acked-by: Sekhar Nori <nsekhar@ti.com> # DaVinci
Acked-by: Christoffer Dall <christoffer.dall@linaro.org> # kvm/hyp
Acked-by: Haojian Zhuang <haojian.zhuang@gmail.com> # PXA3xx
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> # Xen
Tested-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> # ARMv7M
Tested-by: Simon Horman <horms+renesas@verge.net.au> # Shmobile
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>