Make generic code work in presence of system caches ...

On the ARMv8 architecture, cache maintenance operations by set/way on the last
level of integrated cache do not affect the system cache. This means that such a
flush or clean operation could result in the data being pushed out to the system
cache rather than main memory. Another CPU could access this data before it
enables its data cache or MMU. Such accesses could be serviced from the main
memory instead of the system cache. If the data in the sysem cache has not yet
been flushed or evicted to main memory then there could be a loss of
coherency. The only mechanism to guarantee that the main memory will be updated
is to use cache maintenance operations to the PoC by MVA(See section D3.4.11
(System level caches) of ARMv8-A Reference Manual (Issue A.g/ARM DDI0487A.G).

This patch removes the reliance of Trusted Firmware on the flush by set/way
operation to ensure visibility of data in the main memory. Cache maintenance
operations by MVA are now used instead. The following are the broad category of
changes:

1. The RW areas of BL2/BL31/BL32 are invalidated by MVA before the C runtime is
   initialised. This ensures that any stale cache lines at any level of cache
   are removed.

2. Updates to global data in runtime firmware (BL31) by the primary CPU are made
   visible to secondary CPUs using a cache clean operation by MVA.

3. Cache maintenance by set/way operations are only used prior to power down.

NOTE: NON-UPSTREAM TRUSTED FIRMWARE CODE SHOULD MAKE EQUIVALENT CHANGES IN
ORDER TO FUNCTION CORRECTLY ON PLATFORMS WITH SUPPORT FOR SYSTEM CACHES.

Fixes ARM-software/tf-issues#205

Change-Id: I64f1b398de0432813a0e0881d70f8337681f6e9a

PSCI: Migrate TF to the new platform API and CM helpers ...

This patch migrates the rest of Trusted Firmware excluding Secure Payload and
the dispatchers to the new platform and context management API. The per-cpu
data framework APIs which took MPIDRs as their arguments are deleted and only
the ones which take core index as parameter are retained.

Change-Id: I839d05ad995df34d2163a1cfed6baa768a5a595d

Merge pull request #310 from sandrine-bailleux/sb/tf-issue-304-phase1 ...

Enhance BL3-1 entrypoint handling to support non-TF boot firmware - Phase 1

Introduce PROGRAMMABLE_RESET_ADDRESS build option ...

This patch introduces a new platform build option, called
PROGRAMMABLE_RESET_ADDRESS, which tells whether the platform has
a programmable or fixed reset vector address.

If the reset vector address is fixed then the code relies on the
platform_get_entrypoint() mailbox mechanism to figure out where
it is supposed to jump. On the other hand, if it is programmable
then it is assumed that the platform code will program directly
the right address into the RVBAR register (instead of using the
mailbox redirection) so the mailbox is ignored in this case.

Change-Id: If59c3b11fb1f692976e1d8b96c7e2da0ebfba308

Rationalize reset handling code ...

The attempt to run the CPU reset code as soon as possible after reset
results in highly complex conditional code relating to the
RESET_TO_BL31 option.

This patch relaxes this requirement a little. In the BL1, BL3-1 and
PSCI entrypoints code, the sequence of operations is now as follows:
 1) Detect whether it is a cold or warm boot;
 2) For cold boot, detect whether it is the primary or a secondary
    CPU. This is needed to handle multiple CPUs entering cold reset
    simultaneously;
 3) Run the CPU init code.

This patch also abstracts the EL3 registers initialisation done by
the BL1, BL3-1 and PSCI entrypoints into common code.

This improves code re-use and consolidates the code flows for
different types of systems.

NOTE: THE FUNCTION plat_secondary_cold_boot() IS NOW EXPECTED TO
NEVER RETURN. THIS PATCH FORCES PLATFORM PORTS THAT RELIED ON THE
FORMER RETRY LOOP AT THE CALL SITE TO MODIFY THEIR IMPLEMENTATION.
OTHERWISE, SECONDARY CPUS WILL PANIC.

Change-Id: If5ecd74d75bee700b1bd718d23d7556b8f863546

Fix handling of spurious interrupts in BL3_1 ...

There are couple of issues with how the interrupt routing framework in BL3_1
handles spurious interrupts.

1. In the macro 'handle_interrupt_exception', if a spurious interrupt is
   detected by plat_ic_get_pending_interrupt_type(), then execution jumps to
   'interrupt_exit_\label'. This macro uses the el3_exit() function to return to
   the original exception level. el3_exit() attempts to restore the SPSR_EL3 and
   ELR_EL3 registers with values from the current CPU context. Since these
   registers were not saved in this code path, it programs stale values into
   these registers. This leads to unpredictable behaviour after the execution of
   the ERET instruction.

2. When an interrupt is routed to EL3, it could be de-asserted before the
   GICC_HPPIR is read in plat_ic_get_pending_interrupt_type(). There could be
   another interrupt pending at the same time e.g. a non-secure interrupt. Its
   type will be returned instead of the original interrupt. This would result in
   a call to get_interrupt_type_handler(). The firmware will panic if the
   handler for this type of interrupt has not been registered.

This patch fixes the first problem by saving SPSR_EL3 and ELR_EL3 early in the
'handle_interrupt_exception' macro, instead of only doing so once the validity
of the interrupt has been determined.

The second problem is fixed by returning execution back to the lower exception
level through the 'interrupt_exit_\label' label instead of treating it as an
error condition. The 'interrupt_error_\label' label has been removed since it is
no longer used.

Fixes ARM-software/tf-issues#305

Change-Id: I81c729a206d461084db501bb81b44dff435021e8

Add support to indicate size and end of assembly functions ...

In order for the symbol table in the ELF file to contain the size of
functions written in assembly, it is necessary to report it to the
assembler using the .size directive.

To fulfil the above requirements, this patch introduces an 'endfunc'
macro which contains the .endfunc and .size directives. It also adds
a .func directive to the 'func' assembler macro.

The .func/.endfunc have been used so the assembler can fail if
endfunc is omitted.

Fixes ARM-Software/tf-issues#295

Change-Id: If8cb331b03d7f38fe7e3694d4de26f1075b278fc
Signed-off-by: Kévin Petit <kevin.petit@arm.com>

Initialise cpu ops after enabling data cache ...

The cpu-ops pointer was initialized before enabling the data cache in the cold
and warm boot paths. This required a DCIVAC cache maintenance operation to
invalidate any stale cache lines resident in other cpus.

This patch moves this initialization to the bl31_arch_setup() function
which is always called after the data cache and MMU has been enabled.

This change removes the need:
 1. for the DCIVAC cache maintenance operation.
 2. to initialise the CPU ops upon resumption from a PSCI CPU_SUSPEND
    call since memory contents are always preserved in this case.

Change-Id: Ibb2fa2f7460d1a1f1e721242025e382734c204c6

Call reset handlers upon BL3-1 entry. ...

This patch adds support to call the reset_handler() function in BL3-1 in the
cold and warm boot paths when another Boot ROM reset_handler() has already run.

This means the BL1 and BL3-1 versions of the CPU and platform specific reset
handlers may execute different code to each other. This enables a developer to
perform additional actions or undo actions already performed during the first
call of the reset handlers e.g. apply additional errata workarounds.

Typically, the reset handler will be first called from the BL1 Boot ROM. Any
additional functionality can be added to the reset handler when it is called
from BL3-1 resident in RW memory. The constant FIRST_RESET_HANDLER_CALL is used
to identify whether this is the first version of the reset handler code to be
executed or an overridden version of the code.

The Cortex-A57 errata workarounds are applied only if they have not already been
applied.

Fixes ARM-software/tf-issue#275

Change-Id: Id295f106e4fda23d6736debdade2ac7f2a9a9053

Remove coherent memory from the BL memory maps ...

This patch extends the build option `USE_COHERENT_MEMORY` to
conditionally remove coherent memory from the memory maps of
all boot loader stages. The patch also adds necessary
documentation for coherent memory removal in firmware-design,
porting and user guides.

Fixes ARM-Software/tf-issues#106

Change-Id: I260e8768c6a5c2efc402f5804a80657d8ce38773

Miscellaneous documentation fixes ...

This patch gathers miscellaneous minor fixes to the documentation, and comments
in the source code.

Change-Id: I631e3dda5abafa2d90f464edaee069a1e58b751b
Co-Authored-By: Soby Mathew <soby.mathew@arm.com>
Co-Authored-By: Dan Handley <dan.handley@arm.com>

Add CPU specific crash reporting handlers ...

This patch adds handlers for dumping Cortex-A57 and Cortex-A53 specific register
state to the CPU specific operations framework. The contents of CPUECTLR_EL1 are
dumped currently.

Change-Id: I63d3dbfc4ac52fef5e25a8cf6b937c6f0975c8ab

Add CPU specific power management operations ...

This patch adds CPU core and cluster power down sequences to the CPU specific
operations framework introduced in a earlier patch. Cortex-A53, Cortex-A57 and
generic AEM sequences have been added. The latter is suitable for the
Foundation and Base AEM FVPs. A pointer to each CPU's operations structure is
saved in the per-cpu data so that it can be easily accessed during power down
seqeunces.

An optional platform API has been introduced to allow a platform to disable the
Accelerator Coherency Port (ACP) during a cluster power down sequence. The weak
definition of this function (plat_disable_acp()) does not take any action. It
should be overriden with a strong definition if the ACP is present on a
platform.

Change-Id: I8d09bd40d2f528a28d2d3f19b77101178778685d

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

Merge pull request #179 from jcastillo-arm/jc/tf-issues/219 ...

Call platform_is_primary_cpu() only from reset handler

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

Optimize EL3 register state stored in cpu_context structure ...

This patch further optimizes the EL3 register state stored in
cpu_context. The 2 registers which are removed from cpu_context are:

  * cntfrq_el0 is the system timer register which is writable
    only in EL3 and it can be programmed during cold/warm boot. Hence
    it need not be saved to cpu_context.

  * cptr_el3 controls access to Trace, Floating-point, and Advanced
    SIMD functionality and it is programmed every time during cold
    and warm boot. The current BL3-1 implementation does not need to
    modify the access controls during normal execution and hence
    they are expected to remain static.

Fixes ARM-software/tf-issues#197

Change-Id: I599ceee3b73a7dcfd37069fd41b60e3d397a7b18

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

Introduce asm assert and optimize crash reporting

Add CPUECTLR_EL1 and Snoop Control register to crash reporting ...

This patch adds the CPUECTLR_EL1 register and the CCI Snoop Control
register to the list of registers being reported when an unhandled
exception occurs.

Change-Id: I2d997f2d6ef3d7fa1fad5efe3364dc9058f9f22c

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 warm boot path ...

This patch uses stacks allocated in normal memory to enable the MMU early in the
warm boot path thus removing the dependency on stacks allocated in coherent
memory. Necessary cache and stack maintenance is performed when a cpu is being
powered down and up. This avoids any coherency issues that can arise from
reading speculatively fetched stale stack memory from another CPUs cache. These
changes affect the warm boot path in both BL3-1 and BL3-2.

The EL3 system registers responsible for preserving the MMU state are not saved
and restored any longer. Static values are used to program these system
registers when a cpu is powered on or resumed from suspend.

Change-Id: I8357e2eb5eb6c5f448492c5094b82b8927603784

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

Allow FP register context to be optional at build time ...

CTX_INCLUDE_FPREGS make variable allows us to include or exclude FP
registers from context structure, in case FP is not used by TSPD.

Fixes ARM-software/tf-issues#194

Change-Id: Iee41af382d691340c7ae21830ad1bbf95dad1f4b

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

Initialise CPU contexts from entry_point_info ...

Consolidate all BL3-1 CPU context initialization for cold boot, PSCI
and SPDs into two functions:
*  The first uses entry_point_info to initialize the relevant
   cpu_context for first entry into a lower exception level on a CPU
*  The second populates the EL1 and EL2 system registers as needed
   from the cpu_context to ensure correct entry into the lower EL

This patch alters the way that BL3-1 determines which exception level
is used when first entering EL1 or EL2 during cold boot - this is now
fully determined by the SPSR value in the entry_point_info for BL3-3,
as set up by the platform code in BL2 (or otherwise provided to BL3-1).

In the situation that EL1 (or svc mode) is selected for a processor
that supports EL2, the context management code will now configure all
essential EL2 register state to ensure correct execution of EL1. This
allows the platform code to run non-secure EL1 payloads directly
without requiring a small EL2 stub or OS loader.

Change-Id: If9fbb2417e82d2226e47568203d5a369f39d3b0f

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