Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Provide uaccess_save_and_enable() and uaccess_restore() to permit
control of userspace visibility to the kernel, and hook these into
the appropriate places in the kernel where we need to access
userspace.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

The memory copy functions(memcpy, __copy_from_user, __copy_to_user)
never had unwinding annotations added. Currently, when accessing
invalid pointer by these functions occurs the backtrace shown will
stop at these functions or some completely unrelated function.
Add unwinding annotations in hopes of getting a more useful backtrace
in following cases:
1. die on accessing invalid pointer by these functions
2. kprobe trapped at any instruction within these functions
3. interrupted at any instruction within these functions
Signed-off-by: NLin Yongting <linyongting@gmail.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

/tmp/ccJ3ssZW.s: Assembler messages:
/tmp/ccJ3ssZW.s:1952: Error: can't resolve `.text' {.text section} - `.LFB1077'

This is caused because:

	.section .data
	.section .text
	.section .text
	.previous

does not return us to the .text section, but the .data section; this
makes use of .previous dangerous if the ordering of previous sections
is not known.

Fix up the other users of .previous; .pushsection and .popsection are
a safer pairing to use than .section and .previous.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This patch adds the ARM/Thumb-2 unified support for the arch/arm/lib/*
files.
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>

This declaration specifies the "function" type and size for various
assembly functions, mainly needed for generating the correct branch
instructions in Thumb-2.
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Back in the days when we had armo (26-bit) and armv (32-bit) combined,
we had an additional layer to the uaccess macros to ensure correct
typing.  Since we no longer have 26-bit in this tree, we no longer
need this layer, so eliminate it.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Patch from Nicolas Pitre

This patch provides a preemption safe implementation of copy_to_user
and copy_from_user based on the copy template also used for memcpy.
It is enabled unconditionally when CONFIG_PREEMPT=y.  Otherwise if the
configured architecture is not ARMv3 then it is enabled as well as it
gives better performances at least on StrongARM and XScale cores.  If
ARMv3 is not too affected or if it doesn't matter too much then
uaccess.S could be removed altogether.
Signed-off-by: NNicolas Pitre <nico@cam.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>