Introduce a new feature state CHECK_ASYMMETRIC to cater for the features
which are asymmetric across cores. This state is useful for platforms
which has architectural asymmetric cores (A feature is only present in
one type of core e.g. big).
This state is similar to FEAT_STATE_CHECK (dynamic detection) except
that feature state is also checked on each core during warmboot path and
override the context (just for asymmetric features) which was setup by
core executing CPU_ON call.
Only Non-secure context will be re-checked as secure and realm context
is created on same core.
Signed-off-by: Manish Pandey <manish.pandey2@arm.com>
Change-Id: Ic78a0b6ca996e0d7881c43da1a6a0c422f528ef3
The FEATURE_DETECTION functionality had some definitions in a header
file, although they were only used internally in the .c file.
Move them over there, since there are of no interest to other users.
Also use the opportuntiy to rename the less telling FEAT_STATE_[12]
names, and let the "0" case join the game. We use DISABLED, ALWAYS, and
CHECK now, so that the casual reader has some idea what those numbers
are supposed to mean.
feature_panic() becomes "static inline", since disabling all features
makes it unused, so the compiler complains otherwise.
Finally add a new category "cpufeat" to cover CPU feature related
changes.
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Change-Id: If0c8ba91ad22440260ccff383c33bdd055eefbdc
This patch adds architectural features detection procedure to ensure
features enabled are present in the given hardware implementation.
It verifies whether the architecture build flags passed during
compilation match the respective features by reading their ID
registers. It reads through all the enabled feature specific ID
registers at once and panics in case of mismatch(feature enabled
but not implemented in PE).
Feature flags are used at sections (context_management,
save and restore routines of registers) during context switch.
If the enabled feature flag is not supported by the PE, it causes an
exception while saving or restoring the registers guarded by them.
With this mechanism, the build flags are validated at an early
phase prior to their usage, thereby preventing any undefined action
under their control.
This implementation is based on tristate approach for each feature and
currently FEAT_STATE=0 and FEAT_STATE=1 are covered as part of this
patch. FEAT_STATE=2 is planned for phase-2 implementation and will be
taken care separately.
The patch has been explicitly tested, by adding a new test_config
with build config enabling majority of the features and detected
all of them under FVP launched with parameters enabling v8.7 features.
Note: This is an experimental procedure and the mechanism itself is
guarded by a macro "FEATURE_DETECTION", which is currently being
disabled by default.
The "FEATURE_DETECTION" macro is documented and the platforms are
encouraged to make use of this diagnostic tool by enabling this
"FEATURE_DETECTION" flag explicitly and get used to its behaviour
during booting before the procedure gets mandated.
Signed-off-by: Jayanth Dodderi Chidanand <jayanthdodderi.chidanand@arm.com>
Change-Id: Ia23d95430fe82d417a938b672bfb5edc401b0f43
