Introduce interrupt registration framework in BL3-1 ...

This patch introduces a framework for registering interrupts routed to
EL3. The interrupt routing model is governed by the SCR_EL3.IRQ and
FIQ bits and the security state an interrupt is generated in. The
framework recognizes three type of interrupts depending upon which
exception level and security state they should be handled in
i.e. Secure EL1 interrupts, Non-secure interrupts and EL3
interrupts. It provides an API and macros that allow a runtime service
to register an handler for a type of interrupt and specify the routing
model. The framework validates the routing model and uses the context
management framework to ensure that it is applied to the SCR_EL3 prior
to entry into the target security state. It saves the handler in
internal data structures. An API is provided to retrieve the handler
when an interrupt of a particular type is asserted. Registration is
expected to be done once by the primary CPU. The same handler and
routing model is used for all CPUs.

Support for EL3 interrupts will be added to the framework in the
future. A makefile flag has been added to allow the FVP port choose
between ARM GIC v2 and v3 support in EL3. The latter version is
currently unsupported.

A framework for handling interrupts in BL3-1 will be introduced in
subsequent patches. The default routing model in the absence of any
handlers expects no interrupts to be routed to EL3.

Change-Id: Idf7c023b34fcd4800a5980f2bef85e4b5c29e649

Add context library API to change a bit in SCR_EL3 ...

This patch adds an API to write to any bit in the SCR_EL3 member of
the 'cpu_context' structure of the current CPU for a specified
security state. This API will be used in subsequent patches which
introduce interrupt management in EL3 to specify the interrupt routing
model when execution is not in EL3.

It also renames the cm_set_el3_elr() function to cm_set_elr_el3()
which is more in line with the system register name being targeted by
the API.

Change-Id: I310fa7d8f827ad3f350325eca2fb28cb350a85ed

Rework BL3-1 unhandled exception handling and reporting ...

This patch implements the register reporting when unhandled exceptions are
taken in BL3-1. Unhandled exceptions will result in a dump of registers
to the console, before halting execution by that CPU. The Crash Stack,
previously called the Exception Stack, is used for this activity.
This stack is used to preserve the CPU context and runtime stack
contents for debugging and analysis.

This also introduces the per_cpu_ptr_cache, referenced by tpidr_el3,
to provide easy access to some of BL3-1 per-cpu data structures.
Initially, this is used to provide a pointer to the Crash stack.

panic() now prints the the error file and line number in Debug mode
and prints the PC value in release mode.

The Exception Stack is renamed to Crash Stack with this patch.
The original intention of exception stack is no longer valid
since we intend to support several valid exceptions like IRQ
and FIQ in the trusted firmware context. This stack is now
utilized for dumping and reporting the system state when a
crash happens and hence the rename.

Fixes ARM-software/tf-issues#79 Improve reporting of unhandled exception

Change-Id: I260791dc05536b78547412d147193cdccae7811a

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

Always use named structs in header files ...

Add tag names to all unnamed structs in header files. This
allows forward declaration of structs, which is necessary to
reduce header file nesting (to be implemented in a subsequent
commit).

Also change the typedef names across the codebase to use the _t
suffix to be more conformant with the Linux coding style. The
coding style actually prefers us not to use typedefs at all but
this is considered a step too far for Trusted Firmware.

Also change the IO framework structs defintions to use typedef'd
structs to be consistent with the rest of the codebase.

Change-Id: I722b2c86fc0d92e4da3b15e5cab20373dd26786f

Add power management support in the SPD ...

This patch implements a set of handlers in the SPD which are called by
the PSCI runtime service upon receiving a power management
operation. These handlers in turn pass control to the Secure Payload
image if required before returning control to PSCI. This ensures that
the Secure Payload has complete visibility of all power transitions in
the system and can prepare accordingly.

Change-Id: I2d1dba5629b7cf2d53999d39fe807dfcf3f62fe2

Add support for handling runtime service requests ...

This patch uses the reworked exception handling support to handle
runtime service requests through SMCs following the SMC calling
convention. This is a giant commit since all the changes are
inter-related. It does the following:

1. Replace the old exception handling mechanism with the new one
2. Enforce that SP_EL0 is used C runtime stacks.
3. Ensures that the cold and warm boot paths use the 'cpu_context'
   structure to program an ERET into the next lower EL.
4. Ensures that SP_EL3 always points to the next 'cpu_context'
   structure prior to an ERET into the next lower EL
5. Introduces a PSCI SMC handler which completes the use of PSCI as a
   runtime service

Change-Id: I661797f834c0803d2c674d20f504df1b04c2b852
Co-authored-by: Achin Gupta <achin.gupta@arm.com>

Add context management library ...

This patch adds support for a cpu context management library. This
library will be used to:

1. Share pointers to secure and non-secure state cpu contexts between
   runtime services e.g. PSCI and Secure Payload Dispatcher services
2. Set SP_EL3 to a context structure which will be used for
   programming an ERET into a lower EL
3. Provide wrapper functions to save and restore EL3 & EL1
   state. These functions will in turn use the helper functions in
   context.S

Change-Id: I655eeef83dcd2a0c6f2eb2ac23efab866ac83ca0