Introduce framework for CPU specific operations ...

This patch introduces a framework which will allow CPUs to perform
implementation defined actions after a CPU reset, during a CPU or cluster power
down, and when a crash occurs. CPU specific reset handlers have been implemented
in this patch. Other handlers will be implemented in subsequent patches.

Also moved cpu_helpers.S to the new directory lib/cpus/aarch64/.

Change-Id: I1ca1bade4d101d11a898fb30fea2669f9b37b956

Unmask SError interrupt and clear SCR_EL3.EA bit ...

This patch disables routing of external aborts from lower exception levels to
EL3 and ensures that a SError interrupt generated as a result of execution in
EL3 is taken locally instead of a lower exception level.

The SError interrupt is enabled in the TSP code only when the operation has not
been directly initiated by the normal world. This is to prevent the possibility
of an asynchronous external abort which originated in normal world from being
taken when execution is in S-EL1.

Fixes ARM-software/tf-issues#153

Change-Id: I157b996c75996d12fd86d27e98bc73dd8bce6cd5

Call platform_is_primary_cpu() only from reset handler ...

The purpose of platform_is_primary_cpu() is to determine after reset
(BL1 or BL3-1 with reset handler) if the current CPU must follow the
cold boot path (primary CPU), or wait in a safe state (secondary CPU)
until the primary CPU has finished the system initialization.

This patch removes redundant calls to platform_is_primary_cpu() in
subsequent bootloader entrypoints since the reset handler already
guarantees that code is executed exclusively on the primary CPU.

Additionally, this patch removes the weak definition of
platform_is_primary_cpu(), so the implementation of this function
becomes mandatory. Removing the weak symbol avoids other
bootloaders accidentally picking up an invalid definition in case the
porting layer makes the real function available only to BL1.

The define PRIMARY_CPU is no longer mandatory in the platform porting
because platform_is_primary_cpu() hides the implementation details
(for instance, there may be platforms that report the primary CPU in
a system register). The primary CPU definition in FVP has been moved
to fvp_def.h.

The porting guide has been updated accordingly.

Fixes ARM-software/tf-issues#219

Change-Id: If675a1de8e8d25122b7fef147cb238d939f90b5e

Merge pull request #172 from soby-mathew/sm/asm_assert ...

Introduce asm assert and optimize crash reporting

Rework the crash reporting in BL3-1 to use less stack ...

This patch reworks the crash reporting mechanism to further
optimise the stack and code size. The reporting makes use
of assembly console functions to avoid calling C Runtime
to report the CPU state. The crash buffer requirement is
reduced to 64 bytes with this implementation. The crash
buffer is now part of per-cpu data which makes retrieving
the crash buffer trivial.

Also now panic() will use crash reporting if
invoked from BL3-1.

Fixes ARM-software/tf-issues#199

Change-Id: I79d27a4524583d723483165dc40801f45e627da5

Simplify management of SCTLR_EL3 and SCTLR_EL1 ...

This patch reworks the manner in which the M,A, C, SA, I, WXN & EE bits of
SCTLR_EL3 & SCTLR_EL1 are managed. The EE bit is cleared immediately after reset
in EL3. The I, A and SA bits are set next in EL3 and immediately upon entry in
S-EL1. These bits are no longer managed in the blX_arch_setup() functions. They
do not have to be saved and restored either. The M, WXN and optionally the C
bit are set in the enable_mmu_elX() function. This is done during both the warm
and cold boot paths.

Fixes ARM-software/tf-issues#226

Change-Id: Ie894d1a07b8697c116960d858cd138c50bc7a069

Remove coherent stack usage from the cold boot path ...

This patch reworks the cold boot path across the BL1, BL2, BL3-1 and BL3-2 boot
loader stages to not use stacks allocated in coherent memory for early platform
setup and enabling the MMU. Stacks allocated in normal memory are used instead.

Attributes for stack memory change from nGnRnE when the MMU is disabled to
Normal WBWA Inner-shareable when the MMU and data cache are enabled. It is
possible for the CPU to read stale stack memory after the MMU is enabled from
another CPUs cache. Hence, it is unsafe to turn on the MMU and data cache while
using normal stacks when multiple CPUs are a part of the same coherency
domain. It is safe to do so in the cold boot path as only the primary cpu
executes it. The secondary cpus are in a quiescent state.

This patch does not remove the allocation of coherent stack memory. That is done
in a subsequent patch.

Change-Id: I12c80b7c7ab23506d425c5b3a8a7de693498f830

Merge pull request #151 from vikramkanigiri/vk/t133-code-readability ...

Simplify entry point information generation code on FVP

Simplify entry point information generation code on FVP ...

This patch reworks FVP specific code responsible for determining
the entry point information for BL3-2 and BL3-3 stages when BL3-1
is configured as the reset handler.

Change-Id: Ia661ff0a6a44c7aabb0b6c1684b2e8d3642d11ec

Remove early_exceptions from BL3-1 ...

The crash reporting support and early initialisation of the
cpu_data allow the runtime_exception vectors to be used from
the start in BL3-1, removing the need for the additional
early_exception vectors and 2KB of code from BL3-1.

Change-Id: I5f8997dabbaafd8935a7455910b7db174a25d871

Per-cpu data cache restructuring ...

This patch prepares the per-cpu pointer cache for wider use by:
* renaming the structure to cpu_data and placing in new header
* providing accessors for this CPU, or other CPUs
* splitting the initialization of the TPIDR pointer from the
  initialization of the cpu_data content
* moving the crash stack initialization to a crash stack function
* setting the TPIDR pointer very early during boot

Change-Id: Icef9004ff88f8eb241d48c14be3158087d7e49a3

Introduce interrupt handling framework in BL3-1 ...

This patch adds a common handler for FIQ and IRQ exceptions in the
BL3-1 runtime exception vector table. This function determines the
interrupt type and calls its handler. A crash is reported if an
inconsistency in the interrupt management framework is detected. In
the event of a spurious interrupt, execution resumes from the
instruction where the interrupt was generated.

This patch also removes 'cm_macros.S' as its contents have been moved
to 'runtime_exceptions.S'

Change-Id: I3c85ecf8eaf43a3fac429b119ed0bd706d2e2093

Add support for BL3-1 as a reset vector ...

This change adds optional reset vector support to BL3-1
which means BL3-1 entry point can detect cold/warm boot,
initialise primary cpu, set up cci and mail box.

When using BL3-1 as a reset vector it is assumed that
the BL3-1 platform code can determine the location of
the BL3-2 images, or load them as there are no parameters
that can be passed to BL3-1 at reset.

It also fixes the incorrect initialisation of mailbox
registers on the FVP platform

This feature can be enabled by building the code with
make variable RESET_TO_BL31 set as 1

Fixes ARM-software/TF-issues#133
Fixes ARM-software/TF-issues#20

Change-Id: I4e23939b1c518614b899f549f1e8d412538ee570

Populate BL31 input parameters as per new spec ...

This patch is based on spec published at
https://github.com/ARM-software/tf-issues/issues/133

It rearranges the bl31_args struct into
bl31_params and bl31_plat_params which provide the
information needed for Trusted firmware and platform
specific data via x0 and x1

On the FVP platform BL3-1 params and BL3-1 plat params
and its constituents are stored at the start of TZDRAM.

The information about memory availability and size for
BL3-1, BL3-2 and BL3-3 is moved into platform specific data.

Change-Id: I8b32057a3d0dd3968ea26c2541a0714177820da9

Rework handover interface between BL stages ...

This patch reworks the handover interface from: BL1 to BL2 and
BL2 to BL3-1. It removes the raise_el(), change_el(), drop_el()
and run_image() functions as they catered for code paths that were
never exercised.
BL1 calls bl1_run_bl2() to jump into BL2 instead of doing the same
by calling run_image(). Similarly, BL2 issues the SMC to transfer
execution to BL3-1 through BL1 directly. Only x0 and x1 are used
to pass arguments to BL31. These arguments and parameters for
running BL3-1 are passed through a reference to a
'el_change_info_t' structure. They were being passed value in
general purpose registers earlier.

Change-Id: Id4fd019a19a9595de063766d4a66295a2c9307e1

Merge pull request #63 from soby-mathew/sm/save_callee_saved_registers_in_cpu_context-1 ...

Preserve x19-x29 across world switch for exception handling

Preserve x19-x29 across world switch for exception handling ...

Previously exception handlers in BL3-1, X19-X29 were not saved
and restored on every SMC/trap into EL3. Instead these registers
were 'saved as needed' as a side effect of the A64 ABI used by the C
compiler.

That approach failed when world switching but was not visible
with the TSP/TSPD code because the TSP is 64-bit, did not
clobber these registers when running and did not support pre-emption
by normal world interrupts. These scenarios showed
that the values in these registers can be passed through a world
switch, which broke the normal and trusted world assumptions
about these registers being preserved.

The Ideal solution saves and restores these registers when a
world switch occurs - but that type of implementation is more complex.
So this patch always saves and restores these registers on entry and
exit of EL3.

Fixes ARM-software/tf-issues#141

Change-Id: I9a727167bbc594454e81cf78a97ca899dfb11c27

Access system registers directly in assembler ...

Instead of using the system register helper functions to read
or write system registers, assembler coded functions should
use MRS/MSR instructions. This results in faster and more
compact code.

This change replaces all usage of the helper functions with
direct register accesses.

Change-Id: I791d5f11f257010bb3e6a72c6c5ab8779f1982b3

Correct usage of data and instruction barriers ...

The current code does not always use data and instruction
barriers as required by the architecture and frequently uses
barriers excessively due to their inclusion in all of the
write_*() helper functions.

Barriers should be used explicitly in assembler or C code
when modifying processor state that requires the barriers in
order to enable review of correctness of the code.

This patch removes the barriers from the helper functions and
introduces them as necessary elsewhere in the code.

PORTING NOTE: check any port of Trusted Firmware for use of
system register helper functions for reliance on the previous
barrier behaviour and add explicit barriers as necessary.

Fixes ARM-software/tf-issues#92

Change-Id: Ie63e187404ff10e0bdcb39292dd9066cb84c53bf

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

Make use of user/system includes more consistent ...

Make codebase consistent in its use of #include "" syntax for
user includes and #include <> syntax for system includes.

Fixes ARM-software/tf-issues#65

Change-Id: If2f7c4885173b1fd05ac2cde5f1c8a07000c7a33

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

Add support for BL3-2 in BL3-1 ...

This patch adds the following support to the BL3-1 stage:

1. BL3-1 allows runtime services to specify and determine the security
   state of the next image after BL3-1. This has been done by adding
   the `bl31_set_next_image_type()` & `bl31_get_next_image_type()`
   apis. The default security state is non-secure. The platform api
   `bl31_get_next_image_info()` has been modified to let the platform
   decide which is the next image in the desired security state.

2. BL3-1 exports the `bl31_prepare_next_image_entry()` function to
   program entry into the target security state. It uses the apis
   introduced in 1. to do so.

3. BL3-1 reads the information populated by BL2 about the BL3-2 image
   into its internal data structures.

4. BL3-1 introduces a weakly defined reference `bl32_init()` to allow
   initialisation of a BL3-2 image. A runtime service like the Secure
   payload dispatcher will define this function if present.

Change-Id: Icc46dcdb9e475ce6575dd3f9a5dc7a48a83d21d1

Rework BL2 to BL3-1 hand over interface ...

This patch reworks BL2 to BL3-1 hand over interface by introducing a
composite structure (bl31_args) that holds the superset of information
that needs to be passed from BL2 to BL3-1.

  - The extents of secure memory available to BL3-1
  - The extents of memory available to BL3-2 (not yet implemented) and
    BL3-3
  - Information to execute BL3-2 (not yet implemented) and BL3-3 images

This patch also introduces a new platform API (bl2_get_bl31_args_ptr)
that needs to be implemented by the platform code to export reference to
bl31_args structure which has been allocated in platform-defined memory.

The platform will initialize the extents of memory available to BL3-3
during early platform setup in bl31_args structure. This obviates the
need for bl2_get_ns_mem_layout platform API.

BL2 calls the bl2_get_bl31_args_ptr function to get a reference to
bl31_args structure. It uses the 'bl33_meminfo' field of this structure
to load the BL3-3 image. It sets the entry point information for the
BL3-3 image in the 'bl33_image_info' field of this structure. The
reference to this structure is passed to the BL3-1 image.

Also fixes issue ARM-software/tf-issues#25

Change-Id: Ic36426196dd5ebf89e60ff42643bed01b3500517

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>

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

Change comments in assembler files to help ctags ...

Ctags seem to have a problem with generating tags for assembler symbols
when a comment immediately follows an assembly label.

This patch inserts a single space character between the label
definition and the following comments to help ctags.

The patch is generated by the command:

  git ls-files -- \*.S | xargs sed -i 's/^\([^:]\+\):;/\1: ;/1'

Change-Id: If7a3c9d0f51207ea033cc8b8e1b34acaa0926475

Do not trap access to floating point registers ...

Traps when accessing architectural features are disabled by clearing bits
in CPTR_EL3 during early boot, including accesses to floating point
registers. The value of this register was previously undetermined, causing
unwanted traps to EL3. Future EL3 code (for example, context save/restore
code) may use floating point registers, although they are not used by current
code.

Also, the '-mgeneral-regs-only' flag is enabled in the GCC settings to
prevent generation of code that uses floating point registers.

Change-Id: I9a03675f6387bbbee81a6f2c9ccf81150db03747

Update year in copyright text to 2014 ...

Change-Id: Ic7fb61aabae1d515b9e6baf3dd003807ff42da60

Make BL31's ns_entry_info a single-cpu area ...

ns_entry_info used to be a per-cpu array.  This is a waste of space
because it is only accessed by the primary CPU on the cold boot path.
This patch reduces ns_entry_info to a single-cpu area.

Change-Id: I647c70c4e76069560f1aaad37a1d5910f56fba4c