Build system: Add cscope target to the Makefile

Fixes arm-software/tf-issues#15

Signed-off-by: Joakim Bech <joakim.bech@linaro.org>
Allow style checking of tree and local changes

New phony Makefile targets have been added:

 * checkcodebase
 * checkpatch

The checkcodebase target will run a Linux style compliance check over the
entire codebase, and honours the V=1 Makefile verbose setting and so will
show more information when this is enabled.

If the local directory is a git checkout then the output of git ls-files is
used to decide which files to test for compliance.  If the local directory
is not under git control then a 'best attempt' is made, but in this case it
should be noted that it is possible for additional non-codebase files to be
tested, so care should be taken when parsing the output.

The checkpatch target will compare local changes against the git origin/master
to allow issues with the last set of changes to be identified.  To override
the change comparision location, set the BASE_COMMIT variable to your
desired git branch.

Both targets rely on the Linux source tree script checkpatch.pl to do the
syntax checking, and expects that the CHECKPATCH environment variable points
to the location of this file.

Notes on the usage of these targets have been added to the contributing.md
and docs/user-guide.md text files.

Change-Id: I6d73c97af578e24a34226d972afadab9d30f1d8d
Fix memmove and memcpy

memmove needs to allow for overlapping memory regions and, together
with memcpy, should return the input destination pointer, not the
address after the end of the copied data.

fixes ARM-software/tf-issues#18

Signed-off-by: Jon Medhurst <tixy@linaro.org>
Compile assembly files with -DDEBUG flag

Change-Id: Ic6cf19402a0936161baf6b91bf75d64d95269a3c
Fix asserts appearing in release builds

Also fix warnings generated in release builds when assert code
is absent.

Change-Id: I45b9173d3888f9e93e98eb5b4fdc06727ba5cbf4
Add IO abstraction framework

This is intended primarily for use as a storage abstraction.
It allows operations such as image-loading to be implemented
in a platform-independent fashion.  Each platform registers
a set of IO drivers during initialisation.  The platform must
also provide a function that will return a device and a specifier
that can be used to access specified content.

Clients of the API will primarily use device and entity handles.
The term "entity" is deliberately vague, to allow for different
representations of content accessed using different types of
specifier, but will often be interpreted as a "file" where the
specifier will normally be its path.

This commit builds, but is intended to be paired with a sample
implementation of "load_image" using a semi-hosting driver on FVP.

Change-Id: Id3b52f1c0eb9ce76b44b99fc6b6460803668cc86
Implement load_image in terms of IO abstraction

The modified implementation uses the IO abstraction rather than
making direct semi-hosting calls.  The semi-hosting driver is now
registered for the FVP platform during initialisation of each boot
stage where it is used.  Additionally, the FVP platform includes a
straightforward implementation of 'plat_get_image_source' which
provides a generic means for the 'load_image' function to determine
how to access the image data.

Change-Id: Ia34457b471dbee990c7b3c79de7aee4ceea51aa6
Add Firmware Image Package creation tool

This tool can be used to create a Firmware Image Packages (FIP). These
FIPs store a combined set of firmware images with a Table of Contents
(ToC) that can be loaded by the firmware from platform storage.

- Add uuid.h from FreeBSD.
- Use symbolic links to shared headers otherwise unwanted headers and
  definitions are pulled in.
- A FIP is created as part of the default FVP build.
- A BL3-3 image(e.g. UEFI) must be provided.

Change-Id: Ib73feee181df2dba68bf6abec115a83cfa5e26cb
Add Firmware Image Package (FIP) driver

The Firmware Image Package (FIP) driver allows for data to be loaded
from a FIP on platform storage. The FVP supports loading bootloader
images from a FIP located in NOR FLASH.

The implemented FVP policy states that bootloader images will be
loaded from a FIP in NOR FLASH if available and fall back to loading
individual images from semi-hosting.

NOTE:
- BL3-3(e.g. UEFI) is loaded into DRAM and needs to be configured
  to run from the BL33_BASE address. This is currently set to
  DRAM_BASE+128MB for the FVP.

Change-Id: I2e4821748e3376b5f9e467cf3ec09509e43579a0
Add Firmware Image Package (FIP) documentation

This fixes ARM-software/tf-issues#9

Change-Id: Id57037115b8762efc9eaf5ff41887b71d6494c5d
Move translation tables into separate section

This patch moves the translation tables into their own section. This
saves space that would otherwise have been lost in padding due to page
table alignment constraints. The BL31 and BL32 bases have been
consequently adjusted.

Change-Id: Ibd65ae8a5ce4c4ea9a71a794c95bbff40dc63e65
Fix spilled-over BL1 exception vector

The SynchronousExceptionA64 vector has gone beyond the 32-instruction
limit for individual exception vector. This patch splits and relocates
the exception handler so that it fits into the 32-instruction window.

Change-Id: Ic60c4fc3f09a1cb071d63ff0e58353ecaecbb62f
Setup VBAR_EL3 incrementally

This patch ensures that VBAR_EL3 points to the simple stack-less
'early_exceptions' when the C runtime stack is not correctly setup to
use the more complex 'runtime_exceptions'. It is initialised to
'runtime_exceptions' once this is done.

This patch also moves all exception vectors into a '.vectors' section
and modifies linker scripts to place all such sections together. This
will minimize space wastage from alignment restrictions.

Change-Id: I8c3e596ea3412c8bd582af9e8d622bb1cb2e049d
Add helper library for cpu context management

This patch introduces functions for saving and restoring shared system
registers between secure and non-secure EL1 exception levels, VFP
registers and essential EL3 system register and other state. It also
defines the 'cpu_context' data structure which will used for saving and
restoring execution context for a given security state. These functions
will allow runtime services like PSCI and Secure payload dispatcher to
implement logic for switching between the secure and non-secure states.

The save and restore functions follow AArch64 PCS and only use
caller-saved temporary registers.

Change-Id: I8ee3aaa061d3caaedb28ae2c5becb9a206b6fd74
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
psci: Use context library for preserving EL3 state

This patch uses the context library to save and restore EL3 state on
the 'cpu_context' data structures allocated by PSCI for managing
non-secure state context on each cpu.

Change-Id: I19c1f26578204a7cd9e0a6c582ced0d97ee4cf80
Add runtime services framework

This patch introduces the framework to enable registration and
initialisation of runtime services. PSCI is registered and initialised
as a runtime service. Handling of runtime service requests will be
implemented in subsequent patches.

Change-Id: Id21e7ddc5a33d42b7d6e455b41155fc5441a9547
Introduce new exception handling framework

This patch introduces the reworked exception handling logic which lays
the foundation for accessing runtime services in later patches. The
type of an exception has a greater say in the way it is
handled. SP_EL3 is used as the stack pointer for:

1. Determining the type of exception and handling the unexpected ones
   on the exception stack

2. Saving and restoring the essential general purpose and system
   register state after exception entry and prior to exception exit.

SP_EL0 is used as the stack pointer for handling runtime service
requests e.g. SMCs. A new structure for preserving general purpose
register state has been added to the 'cpu_context' structure. All
assembler ensures that it does not use callee saved registers
(x19-x29). The C runtime preserves them across functions calls. Hence
EL3 code does not have to save and restore them explicitly.

Since the exception handling framework has undergone substantial change,
the changes have been kept in separate files to aid readability. These
files will replace the existing ones in subsequent patches.

Change-Id: Ice418686592990ff7a4260771e8d6676e6c8c5ef
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>
Increase coherent stack sizes

This patch increases coherent stack size for both debug and release
builds in order to accommodate stack-heavy printf() and extended EL3
functionality

Change-Id: I30ef30530a01517a97e63d703873374828c09f20