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().

Change-Id: I89b7a5a79dddf6083766a87f9d082c7ee61a54e0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
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.

Change-Id: I1a9508f3adfb0264cac1984d6080d117bfcb39f6
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Nicolas Pitre <nico@linaro.org>

Conflicts:
	arch/arm/vfp/vfpmodule.c
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.

Change-Id: Iddde22ad8684e92e5f0aa4999962ad743eff8f7c
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Nicolas Pitre <nico@linaro.org>

Conflicts:
	arch/arm/vfp/vfpmodule.c
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.

Change-Id: If251e5a16d628ddfdd8d6ce40b78014cd2962d7e
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
ARM: 7780/1: add missing linker section markup to head-common.S

Macro __INIT is used to place various code in head-common.S into the init
section. This should be matched by a closing __FINIT. Also, add an
explicit ".text" to ensure subsequent code is placed into the correct
section; __FINIT is simply a closing marker to match __INIT and doesn't
guarantee to revert to .text.

This historically caused no problem, because macro __CPUINIT was used at
the exact location where __FINIT was missing, which then placed following
code into the cpuinit section. However, with commit 22f0a2736 "init.h:
remove __cpuinit sections from the kernel" applied, __CPUINIT becomes a
no-op, thus leaving all this code in the init section, rather than the
regular text section. This caused issues such as secondary CPU boot
failures or crashes.

Change-Id: I2c346b58c4c4d50a162b19e9967d44ec5e97c7d4
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARM: 7015/1: ARM errata: Possible cache data corruption with hit-under-miss enabled

This patch is a workaround for the 364296 ARM1136 r0p2 erratum (possible
cache data corruption with hit-under-miss enabled). It sets the
undocumented bit 31 in the auxiliary control register and the FI bit in
the control register, thus disabling hit-under-miss without putting the
processor into full low interrupt latency mode.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Conflicts:
	arch/arm/Kconfig
ARM: 7782/1: Kconfig: Let ARM_ERRATA_364296 not depend on CONFIG_SMP

imx_v6_v7_defconfig handles both multi-core and single-core SoCs, and it has CONFIG_SMP=y selected by default.

With such config we cannot select ARM_ERRATA_364296, as it depends on !SMP.

Let ARM_ERRATA_364296 be undependent on CONFIG_SMP, so that we can select this erratum for the ARM1136 SoCs, even if CONFIG_SMP=y is enabled.

Change-Id: Ia96ea3d8e9468884962793cc4a6b19f62e1adc59
Reviewed-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
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

Conflicts:
	arch/arm/vfp/vfpmodule.c
Enable NEON mode by default.
Enable the xor-neon routines.

Sidenode/Question: This should do nothing, because it is only used by some
raid systems, which we doesn't support on our little tablet boards.