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ge, lt, gt and le condition codes in assembly provide a signed test
whereas hs, lo, hi and ls provide the unsigned counterpart. Signed tests
should only be used when strictly necessary, as using them on logically
unsigned values can lead to inverting the test for high enough values.
All offsets, addresses and usually counters are actually unsigned
values, and should be tested as such.

Replace the occurrences of signed condition codes where it was
unnecessary by an unsigned test as the unsigned tests allow the full
range of unsigned values to be used without inverting the result with
some large operands.

Change-Id: I58b7e98d03e3a4476dfb45230311f296d224980a
Signed-off-by: Douglas Raillard <douglas.raillard@arm.com>

Introduce zeromem_dczva function on AArch64 that can handle unaligned
addresses and make use of DC ZVA instruction to zero a whole block at a
time. This zeroing takes place directly in the cache to speed it up
without doing external memory access.

Remove the zeromem16 function on AArch64 and replace it with an alias to
zeromem. This zeromem16 function is now deprecated.

Remove the 16-bytes alignment constraint on __BSS_START__ in
firmware-design.md as it is now not mandatory anymore (it used to comply
with zeromem16 requirements).

Change the 16-bytes alignment constraints in SP min's linker script to a
8-bytes alignment constraint as the AArch32 zeromem implementation is now
more efficient on 8-bytes aligned addresses.

Introduce zero_normalmem and zeromem helpers in platform agnostic header
that are implemented this way:
* AArch32:
	* zero_normalmem: zero using usual data access
	* zeromem: alias for zero_normalmem
* AArch64:
	* zero_normalmem: zero normal memory  using DC ZVA instruction
	                  (needs MMU enabled)
	* zeromem: zero using usual data access

Usage guidelines: in most cases, zero_normalmem should be preferred.

There are 2 scenarios where zeromem (or memset) must be used instead:
* Code that must run with MMU disabled (which means all memory is
  considered device memory for data accesses).
* Code that fills device memory with null bytes.

Optionally, the following rule can be applied if performance is
important:
* Code zeroing small areas (few bytes) that are not secrets should use
  memset to take advantage of compiler optimizations.

  Note: Code zeroing security-related critical information should use
  zero_normalmem/zeromem instead of memset to avoid removal by
  compilers' optimizations in some cases or misbehaving versions of GCC.

Fixes ARM-software/tf-issues#408

Change-Id: Iafd9663fc1070413c3e1904e54091cf60effaa82
Signed-off-by: Douglas Raillard <douglas.raillard@arm.com>

At present the `el3_entrypoint_common` macro uses `memcpy`
function defined in lib/stdlib/mem.c file, to copy data
from ROM to RAM for BL1. Depending on the compiler being
used the stack could potentially be used, in `memcpy`,
for storing the local variables. Since the stack is
initialized much later in `el3_entrypoint_common` it
may result in unknown behaviour.

This patch adds `memcpy4` function definition in assembly so
that it can be used before the stack is initialized and it
also replaces `memcpy` by `memcpy4` in `el3_entrypoint_common`
macro, to copy data from ROM to RAM for BL1.

Change-Id: I3357a0e8095f05f71bbbf0b185585d9499bfd5e0

This patch adds common changes to support AArch32 state in
BL1 and BL2. Following are the changes:

* Added functions for disabling MMU from Secure state.
* Added AArch32 specific SMC function.
* Added semihosting support.
* Added reporting of unhandled exceptions.
* Added uniprocessor stack support.
* Added `el3_entrypoint_common` macro that can be
  shared by BL1 and BL32 (SP_MIN) BL stages. The
  `el3_entrypoint_common` is similar to the AArch64
  counterpart with the main difference in the assembly
  instructions and the registers that are relevant to
  AArch32 execution state.
* Enabled `LOAD_IMAGE_V2` flag in Makefile for
  `ARCH=aarch32` and added check to make sure that
  platform has not overridden to disable it.

Change-Id: I33c6d8dfefb2e5d142fdfd06a0f4a7332962e1a3

This patch adds various assembly helpers for AArch32 like :

* cache management : Functions to flush, invalidate and clean
cache by MVA. Also helpers to do cache operations by set-way
are also added.

* stack management: Macros to declare stack and get the current
stack corresponding to current CPU.

* Misc: Macros to access co processor registers in AArch32,
macros to define functions in assembly, assert macros, generic
`do_panic()` implementation and function to zero block of memory.

Change-Id: I7b78ca3f922c0eda39beb9786b7150e9193425be