Introduce unified API to zero memory ...

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>

Resolve build errors flagged by GCC 6.2 ...

With GCC 6.2 compiler, more C undefined behaviour is being flagged as
warnings, which result in build errors in ARM TF build.

The specific issue that this patch resolves is the use of (1 << 31),
which is predominantly used in case statements, where 1 is represented
as a signed int. When shifted to msb the behaviour is undefined.

The resolution is to specify 1 as an unsigned int using a convenience
macro ULL(). A duplicate macro MAKE_ULL() is replaced.

Fixes ARM-software/tf-issues#438

Change-Id: I08e3053bbcf4c022ee2be33a75bd0056da4073e1
Signed-off-by: David Cunado <david.cunado@arm.com>

utils: move BIT(n) macro to utils.h ...

We are duplicating this macro define, and it is useful enough
to be placed in the common place.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

Move SIZE_FROM_LOG2_WORDS macro to utils.h ...

This patch moves the macro SIZE_FROM_LOG2_WORDS() defined in
`arch.h` to `utils.h` as it is utility macro.

Change-Id: Ia8171a226978f053a1ee4037f80142c0a4d21430

Ensure addresses in is_mem_free() don't overflow ...

This patch adds some runtime checks to prevent some potential
pointer overflow issues in the is_mem_free() function. The overflow
could happen in the case where the end addresses, computed as the
sum of a base address and a size, results in a value large enough
to wrap around. This, in turn, could lead to unpredictable behaviour.

If such an overflow is detected, the is_mem_free() function will now
declare the memory region as not free. The overflow is detected using
a new macro, called check_uptr_overflow().

This patch also modifies all other places in the 'bl_common.c' file
where an end address was computed as the sum of a base address and a
size and instead keeps the two values separate. This avoids the need
to handle pointer overflows everywhere. The code doesn't actually need
to compute any end address before the is_mem_free() function is called
other than to print information message to the serial output.

This patch also introduces 2 slight changes to the reserve_mem()
function:

 - It fixes the end addresses passed to choose_mem_pos(). It was
   incorrectly passing (base + size) instead of (base + size - 1).

 - When the requested allocation size is 0, the function now exits
   straight away and says so using a warning message.
   Previously, it used to actually reserve some memory. A zero-byte
   allocation was not considered as a special case so the function
   was using the same top/bottom allocation mechanism as for any
   other allocation. As a result, the smallest area of memory starting
   from the requested base address within the free region was
   reserved.

Change-Id: I0e695f961e24e56ffe000718014e0496dc6e1ec6

Introduce round_up/down() macros ...

This patch introduces the round_up() and round_down() macros,
which round up (respectively down) a value to a given boundary.
The boundary must be a power of two.

Change-Id: I589dd1074aeb5ec730dd523b4ebf098d55a7e967

Introduce utils.h header file ...

This patch introduces a new header file: include/lib/utils.h.
Its purpose is to provide generic macros and helper functions that
are independent of any BL image, architecture, platform and even
not specific to Trusted Firmware.

For now, it contains only 2 macros: ARRAY_SIZE() and
IS_POWER_OF_TWO(). These were previously defined in bl_common.h and
xlat_tables.c respectively.

bl_common.h includes utils.h to retain compatibility for platforms
that relied on bl_common.h for the ARRAY_SIZE() macro. Upstream
platform ports that use this macro have been updated to include
utils.h.

Change-Id: I960450f54134f25d1710bfbdc4184f12c049a9a9