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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

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>

This patch adds level specific cache maintenance functions
to cache_helpers.S. The new functions 'dcsw_op_levelx',
where '1 <= x <= 3', allow to perform cache maintenance by
set/way for that particular level of cache.  With this patch,
functions to support cache maintenance upto level 3 have
been implemented since it is the highest cache level for
most ARM SoCs.

These functions are now utilized in CPU specific power down
sequences to implement them as mandated by processor specific
technical reference manual.

Change-Id: Icd90ce6b51cff5a12863bcda01b93601417fd45c

Replace the current out-of-line assembler implementations of
the system register and system instruction operations with
inline assembler.

This enables better compiler optimisation and code generation
when accessing system registers.

Fixes ARM-software/tf-issues#91

Change-Id: I149af3a94e1e5e5140a3e44b9abfc37ba2324476

The data cache clean and invalidate operations dcsw_op_all()
and dcsw_op_loius() were implemented to invoke a DSB and ISB
barrier for every set/way operation. This adds a substantial
performance penalty to an already expensive operation.

These functions have been reworked to provide an optimised
implementation derived from the code in section D3.4 of the
ARMv8 ARM. The helper macro setup_dcsw_op_args has been moved
and reworked alongside the implementation.

Fixes ARM-software/tf-issues#146

Change-Id: Icd5df57816a83f0a842fce935320a369f7465c7f

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 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

Move almost all system include files to a logical sub-directory
under ./include. The only remaining system include directories
not under ./include are specific to the platform. Move the
corresponding source files to match the include directory
structure.

Also remove pm.h as it is no longer used.

Change-Id: Ie5ea6368ec5fad459f3e8a802ad129135527f0b3

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

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

Change-Id: Ic7fb61aabae1d515b9e6baf3dd003807ff42da60

- Add instructions for contributing to ARM Trusted Firmware.

- Update copyright text in all files to acknowledge contributors.

Change-Id: I9311aac81b00c6c167d2f8c889aea403b84450e5