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The LDNP/STNP instructions as implemented on Cortex-A53 and
Cortex-A57 do not behave in a way most programmers expect, and will
most probably result in a significant speed degradation to any code
that employs them. The ARMv8-A architecture (see Document ARM DDI
0487A.h, section D3.4.3) allows cores to ignore the non-temporal hint
and treat LDNP/STNP as LDP/STP instead.

This patch introduces 2 new build flags:
A53_DISABLE_NON_TEMPORAL_HINT and A57_DISABLE_NON_TEMPORAL_HINT
to enforce this behaviour on Cortex-A53 and Cortex-A57. They are
enabled by default.

The string printed in debug builds when a specific CPU errata
workaround is compiled in but skipped at runtime has been
generalised, so that it can be reused for the non-temporal hint use
case as well.

Change-Id: I3e354f4797fd5d3959872a678e160322b13867a1

- Apply a53 errata #826319 to revision <= r0p2
- Apply a53 errata #836870 to revision <= r0p3
- Update docs/cpu-specific-build-macros.md for newly added errata build flags

Change-Id: I44918e36b47dca1fa29695b68700ff9bf888865e
Signed-off-by: Jimmy Huang <jimmy.huang@mediatek.com>

Change-Id: Iaf9d6305edc478d39cf1b37c8a70ccdf723e8ef9

Fixes arm-software/tf-issues#276

This patch optimizes the Cortex-A57 cluster power down sequence by not
flushing the Level1 data cache. The L1 data cache and the L2 unified
cache are inclusive. A flush of the L2 by set/way flushes any dirty
lines from the L1 as well. This is a known safe deviation from the
Cortex-A57 TRM defined power down sequence. This optimization can be
enabled by the platform through the 'SKIP_A57_L1_FLUSH_PWR_DWN' build
flag. Each Cortex-A57 based platform must make its own decision on
whether to use the optimization.

This patch also renames the cpu-errata-workarounds.md to
cpu-specific-build-macros.md as this facilitates documentation
of both CPU Specific errata and CPU Specific Optimization
build macros.

Change-Id: I299b9fe79e9a7e08e8a0dffb7d345f9a00a71480

Prior to this patch, the errata workarounds were applied for any version
of the CPU in the release build and in the debug build an assert
failure resulted when the revision did not match. This patch applies
errata workarounds in the Cortex-A57 reset handler only if the 'variant'
and 'revision' fields read from the MIDR_EL1 match. In the debug build,
a warning message is printed for each errata workaround which is not
applied.

The patch modifies the register usage in 'reset_handler` so
as to adhere to ARM procedure calling standards.

Fixes ARM-software/tf-issues#242

Change-Id: I51b1f876474599db885afa03346e38a476f84c29

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>

This patch adds documentation for CPU specific abstraction in the firmware-
design.md and adds a new document cpu-errata-workarounds.md to describe
the cpu errata workaround build flags.

Change-Id: Ia08c2fec0b868a0a107d0264e87a60182797a1bd