Add enable mmu platform porting interfaces ...

Previously, the enable_mmu_elX() functions were implicitly part of
the platform porting layer since they were included by generic
code. These functions have been placed behind 2 new platform
functions, bl31_plat_enable_mmu() and bl32_plat_enable_mmu().
These are weakly defined so that they can be optionally overridden
by platform ports.

Also, the enable_mmu_elX() functions have been moved to
lib/aarch64/xlat_tables.c for optional re-use by platform ports.
These functions are tightly coupled with the translation table
initialization code.

Fixes ARM-software/tf-issues#152

Change-Id: I0a2251ce76acfa3c27541f832a9efaa49135cc1c

Use a vector table for TSP entrypoints ...

The TSP has a number of entrypoints used by the TSP on different
occasions. These were provided to the TSPD as a table of function
pointers, and required the TSPD to read the entry in the table,
which is in TSP memory, in order to program the exception return
address.

Ideally, the TSPD has no access to the TSP memory.

This patch changes the table of function pointers into a vector
table of single instruction entrypoints. This allows the TSPD to
calculate the entrypoint address instead of read it.

Fixes ARM-software/tf-issues#160

Change-Id: Iec6e055d537ade78a45799fbc6f43765a4725ad3

Non-Secure Interrupt support during Standard SMC processing in TSP ...

Implements support for Non Secure Interrupts preempting the
Standard SMC call in EL1. Whenever an IRQ is trapped in the
Secure world we securely handover to the Normal world
to process the interrupt. The normal world then issues
"resume" smc call to resume the previous interrupted SMC call.
Fixes ARM-software/tf-issues#105

Change-Id: I72b760617dee27438754cdfc9fe9bcf4cc024858

Add support for asynchronous FIQ handling in TSP ...

This patch adds support in the TSP to handle FIQ interrupts that are
generated when execution is in the TSP. S-EL1 interrupt are handled
normally and execution resumes at the instruction where the exception
was originally taken. S-EL3 interrupts i.e. any interrupt not
recognized by the TSP are handed to the TSPD. Execution resumes
normally once such an interrupt has been handled at EL3.

Change-Id: Ia3ada9a4fb15670afcc12538a6456f21efe58a8f

Add support for synchronous FIQ handling in TSP ...

This patch adds support in the TSP for handling S-EL1 interrupts
handed over by the TSPD. It includes GIC support in its platform port,
updates various statistics related to FIQ handling, exports an entry
point that the TSPD can use to hand over interrupts and defines the
handover protocol w.r.t what context is the TSP expected to preserve
and the state in which the entry point is invoked by the TSPD.

Change-Id: I93b22e5a8133400e4da366f5fc862f871038df39

Rework memory information passing to BL3-x images ...

The issues addressed in this patch are:

1. Remove meminfo_t from the common interfaces in BL3-x,
expecting that platform code will find a suitable mechanism
to determine the memory extents in these images and provide
it to the BL3-x images.

2. Remove meminfo_t and bl31_plat_params_t from all FVP BL3-x
code as the images use link-time information to determine
memory extents.

meminfo_t is still used by common interface in BL1/BL2 for
loading images

Change-Id: I4e825ebf6f515b59d84dc2bdddf6edbf15e2d60f

fvp: Provide per-EL MMU setup functions ...

Instead of having a single version of the MMU setup functions for all
bootloader images that can execute either in EL3 or in EL1, provide
separate functions for EL1 and EL3. Each bootloader image can then
call the appropriate version of these functions. The aim is to reduce
the amount of code compiled in each BL image by embedding only what's
needed (e.g. BL1 to embed only EL3 variants).

Change-Id: Ib86831d5450cf778ae78c9c1f7553fe91274c2fa

Reduce deep nesting of header files ...

Reduce the number of header files included from other header
files as much as possible without splitting the files. Use forward
declarations where possible. This allows removal of some unnecessary
"#ifndef __ASSEMBLY__" statements.

Also, review the .c and .S files for which header files really need
including and reorder the #include statements alphabetically.

Fixes ARM-software/tf-issues#31

Change-Id: Iec92fb976334c77453e010b60bcf56f3be72bd3e

Place assembler functions in separate sections ...

This extends the --gc-sections behaviour to the many assembler
support functions in the firmware images by placing each function
into its own code section. This is achieved by creating a 'func'
macro used to declare each function label.

Fixes ARM-software/tf-issues#80

Change-Id: I301937b630add292d2dec6d2561a7fcfa6fec690

Rework arithmetic operations in Test Secure Payload ...

This patch reworks the service provided by the TSP to perform common
arithmetic operations on a set of arguments provided by the non-secure
world. For a addition, division, subtraction & multiplication operation
requested on two arguments in x0 and x1 the steps are:

1. TSPD saves the non-secure context and passes the operation and its
   arguments to the TSP.

2. TSP asks the TSPD to return the same arguments once again. This
   exercises an additional SMC path.

3. TSP now has two copies of both x0 and x1. It performs the operation
   on the corresponding copies i.e. in case of addition it returns x0+x0
   and x1+x1.

4. TSPD receives the result, saves the secure context, restores the
   non-secure context and passes the result back to the non-secure
   client.

Change-Id: I6eebfa2ae0a6f28b1d2e11a31f575c7a4b96724b
Co-authored-by: Jeenu Viswambharan <jeenu.viswambharan@arm.com>

Add Test Secure Payload (BL3-2) image ...

This patch adds a simple TSP as the BL3-2 image. The secure payload
executes in S-EL1. It paves the way for the addition of the TSP
dispatcher runtime service to BL3-1. The TSP and the dispatcher service
will serve as an example of the runtime firmware's ability to toggle
execution between the non-secure and secure states in response to SMC
request from the non-secure state.  The TSP will be replaced by a
Trusted OS in a real system.

The TSP also exports a set of handlers which should be called in
response to a PSCI power management event e.g a cpu being suspended or
turned off. For now it runs out of Secure DRAM on the ARM FVP port and
will be moved to Secure SRAM later. The default translation table setup
code assumes that the caller is executing out of secure SRAM. Hence the
TSP exports its own translation table setup function.

The TSP only services Fast SMCs, is non-reentrant and non-interruptible.
It does arithmetic operations on two sets of four operands, one set
supplied by the non-secure client, and the other supplied by the TSP
dispatcher in EL3. It returns the result according to the Secure Monitor
Calling convention standard.

This TSP has two functional entry points:

- An initial, one-time entry point through which the TSP is initialized
  and prepares for receiving further requests from secure
  monitor/dispatcher

- A fast SMC service entry point through which the TSP dispatcher
  requests secure services on behalf of the non-secure client

Change-Id: I24377df53399307e2560a025eb2c82ce98ab3931
Co-authored-by: Jeenu Viswambharan <jeenu.viswambharan@arm.com>