The flush_cache_user_range macro takes a pair of addresses describing
the start and end of the virtual address range to flush. Due to an
accidental oversight when flush_cache_range_user was introduced, the
address range was rounded up so that the start and end addresses were
page-aligned.

For historical reference, the interesting commits in history.git are:

10eacf1775e1 ("[ARM] Clean up ARM cache handling interfaces (part 1)")
71432e79b76b ("[ARM] Add flush_cache_user_page() for sys_cacheflush()")

This patch removes the alignment code, reducing the amount of flushing
required for ranges that are not an exact multiple of PAGE_SIZE.

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Jonathan Austin <jonathan.austin@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

flush_cache_vmap contains a dsb to ensure that any cacheflushing
operations to flush out newly written ptes have completed.

This patch adds the -ishst option to the dsb, since that is all that is
required for completing cacheflushing in the inner-shareable domain.

Signed-off-by: Will Deacon <will.deacon@arm.com>

Commit f8b63c1 made flush_kernel_dcache_page a no-op assuming that
the pages it needs to handle are kernel mapped only.  However, for
example when doing direct I/O, pages with user space mappings may
occur.

Thus, continue to do lazy flushing if there are no user space
mappings.  Otherwise, flush the kernel cache lines directly.

Signed-off-by: Simon Baatz <gmbnomis@gmail.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: <stable@vger.kernel.org> # 3.2+
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Algorithms used by the MCPM layer rely on state variables which are
accessed while the cache is either active or inactive, depending
on the code path and the active state.

This patch introduces generic cache maintenance helpers to provide the
necessary cache synchronization for such state variables to always hit
main memory in an ordered way.

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

ARM v7 architecture introduced the concept of cache levels and related
control registers. New processors like A7 and A15 embed an L2 unified cache
controller that becomes part of the cache level hierarchy. Some operations in
the kernel like cpu_suspend and __cpu_disable do not require a flush of the
entire cache hierarchy to DRAM but just the cache levels belonging to the
Level of Unification Inner Shareable (LoUIS), which in most of ARM v7 systems
correspond to L1.

The current cache flushing API used in cpu_suspend and __cpu_disable,
flush_cache_all(), ends up flushing the whole cache hierarchy since for
v7 it cleans and invalidates all cache levels up to Level of Coherency
(LoC) which cripples system performance when used in hot paths like hotplug
and cpuidle.

Therefore a new kernel cache maintenance API must be added to cope with
latest ARM system requirements.

This patch adds flush_cache_louis() to the ARM kernel cache maintenance API.

This function cleans and invalidates all data cache levels up to the
Level of Unification Inner Shareable (LoUIS) and invalidates the instruction
cache for processors that support it (> v7).

This patch also creates an alias of the cache LoUIS function to flush_kern_all
for all processor versions prior to v7, so that the current cache flushing
behaviour is unchanged for those processors.

v7 cache maintenance code implements a cache LoUIS function that cleans and
invalidates the D-cache up to LoUIS and invalidates the I-cache, according
to the new API.

Reviewed-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Reviewed-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Tested-by: Shawn Guo <shawn.guo@linaro.org>

The vivt_flush_cache_{range,page} functions check that the mm_struct
of the VMA being flushed has been active on the current CPU before
performing the cache maintenance.

The gate_vma has a NULL mm_struct pointer and, as such, will cause a
kernel fault if we try to flush it with the above operations. This
happens during ELF core dumps, which include the gate_vma as it may be
useful for debugging purposes.

This patch adds checks to the VIVT cache flushing functions so that VMAs
with a NULL mm_struct are flushed unconditionally (the vectors page may
be dirty if we use it to store the current TLS pointer).

Cc: <stable@vger.kernel.org> # 3.4+
Reported-by: Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
Tested-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

The cacheflush syscall can fail for two reasons:

(1) The arguments are invalid (nonsensical address range or no VMA)

(2) The region generates a translation fault on a VIPT or PIPT cache

This patch allows do_cache_op to return an error code to userspace in
the case of the above. The various coherent_user_range implementations
are modified to return 0 in the case of VIVT caches or -EFAULT in the
case of an abort on v6/v7 cores.

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

vma isn't used and flush_cache_user_range isn't a standard macro that
is used on several archs with the same prototype. In fact only unicore32
has a macro with the same name (with an identical implementation and no
in-tree users).

This is a part of a patch proposed by Dima Zavin (with Message-id:
1272439931-12795-1-git-send-email-dima@android.com) that didn't get
accepted.

Cc: Dima Zavin <dima@android.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Conflicts:
	arch/arm/include/asm/cacheflush.h
	arch/arm/include/asm/proc-fns.h
	arch/arm/mm/Kconfig