ARM: move VFP init to an earlier boot stage

In order to use the NEON unit in the kernel, we should
initialize it a bit earlier in the boot process so NEON users
that like to do a quick benchmark at load time (like the
xor_blocks or RAID-6 code) find the NEON/VFP unit already
enabled.

Replaced late_initcall() with core_initcall().

Signed-off-by: Ard Biesheuvel <ard.biesheuvel at linaro.org>
Acked-by: Nicolas Pitre <nico at linaro.org>

Signed-off-by: Paul Reioux <reioux@gmail.com>
ARM: be strict about FP exceptions in kernel mode

The support code in vfp_support_entry does not care whether the
exception that caused it to be invoked occurred in kernel mode or
in user mode. However, neither condition that could trigger this
exception (lazy restore and VFP bounce to support code) is
currently allowable in kernel mode.

In either case, print a message describing the condition before
letting the undefined instruction handler run its course and trigger
an oops.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel at linaro.org>
Acked-by: Nicolas Pitre <nico at linaro.org>
Signed-off-by: Paul Reioux <reioux@gmail.com>
ARM: add support for kernel mode NEON

In order to safely support the use of NEON instructions in
kernel mode, some precautions need to be taken:
- the userland context that may be present in the registers (even
  if the NEON/VFP is currently disabled) must be stored under the
  correct task (which may not be 'current' in the UP case),
- to avoid having to keep track of additional vfpstates for the
  kernel side, disallow the use of NEON in interrupt context
  and run with preemption disabled,
- after use, re-enable preemption and re-enable the lazy restore
  machinery by disabling the NEON/VFP unit.

This patch adds the functions kernel_neon_begin() and
kernel_neon_end() which take care of the above. It also adds
the Kconfig symbol KERNEL_MODE_NEON to enable it.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Nicolas Pitre <nico@linaro.org>

Signed-off-by: Paul Reioux <reioux@gmail.com>
ARM: crypto: add NEON accelerated XOR implementation

Add a source file xor-neon.c (which is really just the reference
C implementation passed through the GCC vectorizer) and hook it
up to the XOR framework.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
ARM: 7835/2: fix modular build of xor_blocks() with NEON enabled

Commit 0195659 introduced a NEON accelerated version of the xor_blocks()
function, but it needs the changes in this patch to allow it to be built
as a module rather than statically into the kernel.

This patch creates a separate module xor-neon.ko which exports the NEON
inner xor_blocks() functions depended upon by the regular xor.ko if it
is built with CONFIG_KERNEL_MODE_NEON=y

Reported-by: Josh Boyer <jwboyer@fedoraproject.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARM: only allow kernel mode neon with AEABI

This prevents the linker erroring with:

arm-linux-ld: error: arch/arm/lib/xor-neon.o uses VFP instructions, whereas arch/arm/lib/built-in.o does not
arm-linux-ld: failed to merge target specific data of file arch/arm/lib/xor-neon.o

This is due to the non-neon files being marked as containing FPA data/
instructions (even though they do not) being mixed with files which
contain VFP, which is an incompatible floating point format.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
arm: vfpmodule: Fix warning procfs vfp_bounce reporting failed

Creation of procfs cpu/vfp_bounce fails because we're initialized too early. Fix
this by creating it on rootfs_initcall as before the NEON patches.

<6>[    0.130770] VFP support v0.3: implementor 51 architecture 64 part 6f varia
nt 2 rev 0
<4>[    0.130795] ------------[ cut here ]------------
<4>[    0.130813] WARNING: at fs/proc/generic.c:323 __xlate_proc_name+0xac/0xcc(
)
<4>[    0.130822] name 'cpu/vfp_bounce'
<4>[    0.130855] [<c010e26c>] (unwind_backtrace+0x0/0x144) from [<c0a20f58>] (d
ump_stack+0x20/0x24)
<4>[    0.130879] [<c0a20f58>] (dump_stack+0x20/0x24) from [<c019b670>] (warn_sl
owpath_common+0x58/0x70)
<4>[    0.130899] [<c019b670>] (warn_slowpath_common+0x58/0x70) from [<c019b704>
] (warn_slowpath_fmt+0x40/0x48)
<4>[    0.130919] [<c019b704>] (warn_slowpath_fmt+0x40/0x48) from [<c02c2ad8>] (
__xlate_proc_name+0xac/0xcc)
<4>[    0.130938] [<c02c2ad8>] (__xlate_proc_name+0xac/0xcc) from [<c02c2b50>] (
__proc_create+0x58/0x100)
<4>[    0.130956] [<c02c2b50>] (__proc_create+0x58/0x100) from [<c02c2ed0>] (pro
c_create_data+0x5c/0xc0)
<4>[    0.130979] [<c02c2ed0>] (proc_create_data+0x5c/0xc0) from [<c0f03484>] (v
fp_init+0x19c/0x200)
<4>[    0.131000] [<c0f03484>] (vfp_init+0x19c/0x200) from [<c0f00c98>] (do_one_
initcall+0x98/0x168)
<4>[    0.131020] [<c0f00c98>] (do_one_initcall+0x98/0x168) from [<c0f00e60>] (k
ernel_init+0xf8/0x1b4)
<4>[    0.131043] [<c0f00e60>] (kernel_init+0xf8/0x1b4) from [<c01081a0>] (kerne
l_thread_exit+0x0/0x8)
<4>[    0.131076] ---[ end trace ea6d9a9b5e947151 ]---
<3>[    0.131086] Failed to create procfs node for VFP bounce reporting

Signed-off-by: Paul Reioux <reioux@gmail.com>
Enable KERNEL_MODE_NEON in defconfig
ARM: mm: implement LoUIS API for cache maintenance ops

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@xxxxxx>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>

Signed-off-by: Paul Reioux <reioux@gmail.com>
ARM: mm: rename jump labels in v7_flush_dcache_all function

This patch renames jump labels in v7_flush_dcache_all in order to define
a specific flush cache levels entry point.

TODO: factor out the level flushing loop if considered worthwhile and
      define the input registers requirements.

Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
Signed-off-by: Paul Reioux <reioux@gmail.com>
ARM: kernel: update cpu_suspend code to use cache LoUIS operations

In processors like A15/A7 L2 cache is unified and integrated within the
processor cache hierarchy, so that it is not considered an outer cache
anymore. For processors like A15/A7 flush_cache_all() ends up cleaning
all cache levels up to Level of Coherency (LoC) that includes
the L2 unified cache.

When a single CPU is suspended (CPU idle) a complete L2 clean is not
required, so generic cpu_suspend code must clean the data cache using the
newly introduced cache LoUIS function.

The context and stack pointer (context pointer) are cleaned to main memory
using cache area functions that operate on MVA and guarantee that the data
is written back to main memory (perform cache cleaning up to the Point of
Coherency - PoC) so that the processor can fetch the context when the MMU
is off in the cpu_resume code path.

outer_cache management remains unchanged.

Reviewed-by: Santosh Shilimkar <santosh.shilimkar@xxxxxx>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
Signed-off-by: Paul Reioux <reioux@gmail.com>
ARM: kernel: update __cpu_disable to use cache LoUIS maintenance API

When a CPU is hotplugged out caches that reside in its power domain
lose their contents and so must be cleaned to the next memory level.

Currently, __cpu_disable calls flush_cache_all() that for new generation
processor like A15/A7 ends up cleaning and invalidating all cache levels
up to Level of Coherency, which includes the unified L2.

This ends up being a waste of cycles since the L2 cache contents are not
lost on power down.

This patch updates __cpu_disable to use the new LoUIS API cache operations.

Reviewed-by: Santosh Shilimkar <santosh.shilimkar@xxxxxx>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
Signed-off-by: Paul Reioux <reioux@gmail.com>
ARM: mm: update __v7_setup() to the new LoUIS cache maintenance API

The ARMv7 processor setup function __v7_setup() cleans and invalidates the
CPU cache before enabling MMU to start the CPU with a clean CPU local cache.

But on ARMv7 architectures like Cortex-[A15/A8], this code will end
up flushing the L2 caches(up to level of Coherency) which is undesirable
and expensive. The setup functions are used in the CPU hotplug scenario too
and hence flushing all cache levels should be avoided.

This patch replaces the cache flushing call with the newly introduced
v7 dcache LoUIS API where only cache levels up to LoUIS are cleaned and
invalidated when a processors executes __v7_setup which is the expected
behavior.

For processors like A9 and A5 where the L2 cache is an outer one the
behavior should be unchanged.

Signed-off-by: Santosh Shilimkar <santosh.shilimkar@xxxxxx>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
Signed-off-by: Paul Reioux <reioux@gmail.com>