ARM: nommu: define dummy TLB operations for nommu configurations

nommu platforms do not perform address translation and therefore clearly
don't have TLBs. However, some SMP code assumes the presence of the TLB
flushing routines and will therefore fail to compile for a nommu system.

This patch defines dummy local_* TLB operations and #defines
tlb_ops_need_broadcast() as 0, therefore causing the usual ARM SMP TLB
operations to call the local variants instead.

Signed-off-by: Will Deacon <will.deacon@arm.com>
CC: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
CC: Nicolas Pitre <nico@linaro.org>

Conflicts:
	arch/arm/include/asm/smp_plat.h
	arch/arm/include/asm/tlbflush.h
ARM: nommu: provide dummy cpu_switch_mm implementation

cpu_switch_mm is a logical nop on nommu systems, so define it as such
when !CONFIG_MMU.

Signed-off-by: Will Deacon <will.deacon@arm.com>
ARM: nommu: add stub local_flush_bp_all() for !CONFIG_MMUU

Since the merging of Will's tlb-ops branch, specifically 89c7e4b8bbb3
(ARM: 7661/1: mm: perform explicit branch predictor maintenance when required),
building SMP without CONFIG_MMU has been broken.

The local_flush_bp_all function is only called for operations related to
changing the kernel's view of memory and ASID rollover - both of which are
irrelevant to an !MMU kernel.

This patch adds a stub local_flush_bp_all() function to the other tlb
maintenance stubs and restores the ability to build an SMP !MMU kernel.

Signed-off-by: Jonathan Austin <jonathan.austin@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
ARM: mpu: add PMSA related registers and bitfields to existing headers

This patch adds the following definitions relevant to the PMSA:

Add SCTLR bit 17, (CR_BR - Background Region bit) to the list of CR_*
bitfields. This bit determines whether to use the architecturally defined
memory map

Add the MPUIR to the available registers when using read_cpuid macro. The
MPUIR is the MPU type register.

Signed-off-by: Jonathan Austin <jonathan.austin@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
CC:"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
Signed-off-by: Jake Weinstein <xboxlover360@gmail.com>
ARM: mpu: add header for MPU register layouts and region data

This commit adds definitions relevant to the ARM v7 PMSA compliant MPU.

The register layouts and region configuration data is made accessible to asm
as well as C-code so that it can be used in early bring-up of the MPU.

The mpu region information structs assume that the properties for the I/D side
are the same, though the implementation could be trivially extended for future
platforms where this is no-longer true.

The MPU_*_REGION defines are used for the basic, static MPU region setup.

Signed-off-by: Jonathan Austin <jonathan.austin@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Jake Weinstein <xboxlover360@gmail.com>
ARM: mpu: add early bring-up code for the ARMv7 PMSA-compliant MPU

This patch adds initial support for using the MPU, which is necessary for
SMP operation on PMSAv7 processors because it is the only way to ensure
memory is shared. This is an initial patch and full SMP support is added
later in this series.

The setup of the MPU is performed in a way analagous to that for the MMU:
Very early initialisation before the C environment is brought up, followed
by a sanity check and more complete initialisation in C.

This patch provides the simplest possible memory region configuration:
MPU_PROBE_REGION: Reserved for probing MPU details, not enabled
MPU_BG_REGION: A 'background' region that specifies all memory strongly ordered
MPU_RAM_REGION: A single shared, cacheable, normal region for the valid RAM.

In this early initialisation code we simply map the whole of the address
space with the BG_REGION and (at least) the kernel with the RAM_REGION. The
MPU has region alignment constraints that require us to round past the end
of the kernel.

As region 2 has a higher priority than region 1, it overrides the strongly-
ordered behaviour for RAM only.

Subsequent patches will add more complete initialisation from the C-world
and support for bringing up secondary CPUs.

Signed-off-by: Jonathan Austin <jonathan.austin@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
CC: Hyok S. Choi <hyok.choi@samsung.com>
Signed-off-by: Jake Weinstein <xboxlover360@gmail.com>

Conflicts:
	arch/arm/kernel/head-nommu.S
ARM: mpu: add MPU initialisation for secondary cores

The MPU initialisation on the primary core is performed in two stages, one
minimal stage to ensure the CPU can boot and a second one after
sanity_check_meminfo. As the memory configuration is known by the time we
boot secondary cores only a single step is necessary, provided the values
for DRSR are passed to secondaries.

This patch implements this arrangement. The configuration generated for the
MPU regions is made available to the secondary core, which can then use the
asm MPU intialisation code to program a complete region configuration.

This is necessary for SMP configurations without an MMU, as the MPU
initialisation is the only way to ensure that memory is specified as
'shared'.

Signed-off-by: Jonathan Austin <jonathan.austin@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
CC: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Jake Weinstein <xboxlover360@gmail.com>

Conflicts:
	arch/arm/kernel/head-nommu.S
	arch/arm/kernel/smp.c
ARM: cacheflush: add synchronization helpers for mixed cache state accesses

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>
Signed-off-by: Jake Weinstein <xboxlover360@gmail.com>

Conflicts:
	arch/arm/include/asm/cacheflush.h