refactor(el3-runtime): add arch-features detection mechanism
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
diff --git a/make_helpers/defaults.mk b/make_helpers/defaults.mk
index 910ffdf..99f44a4 100644
--- a/make_helpers/defaults.mk
+++ b/make_helpers/defaults.mk
@@ -133,12 +133,18 @@
# Use BRANCH_PROTECTION to enable PAUTH.
ENABLE_PAUTH := 0
-# Flag to enable access to the HCRX_EL2 register by setting SCR_EL3.HXEn.
-ENABLE_FEAT_HCX := 0
-
# Flag to enable access to the HAFGRTR_EL2 register
ENABLE_FEAT_AMUv1 := 0
+# Flag to enable AMUv1p1 extension.
+ENABLE_FEAT_AMUv1p1 := 0
+
+# Flag to enable CSV2_2 extension.
+ENABLE_FEAT_CSV2_2 := 0
+
+# Flag to enable access to the HCRX_EL2 register by setting SCR_EL3.HXEn.
+ENABLE_FEAT_HCX := 0
+
# Flag to enable access to the HDFGRTR_EL2 register
ENABLE_FEAT_FGT := 0
@@ -148,6 +154,21 @@
# Flag to enable use of the DIT feature.
ENABLE_FEAT_DIT := 0
+# Flag to enable access to Privileged Access Never bit of PSTATE.
+ENABLE_FEAT_PAN := 0
+
+# Flag to enable access to the Random Number Generator registers
+ENABLE_FEAT_RNG := 0
+
+# Flag to enable Speculation Barrier Instruction
+ENABLE_FEAT_SB := 0
+
+# Flag to enable Secure EL-2 feature.
+ENABLE_FEAT_SEL2 := 0
+
+# Flag to enable Virtualization Host Extensions
+ENABLE_FEAT_VHE := 0
+
# By default BL31 encryption disabled
ENCRYPT_BL31 := 0
@@ -166,6 +187,9 @@
# Fault injection support
FAULT_INJECTION_SUPPORT := 0
+# Flag to enable architectural features detection mechanism
+FEATURE_DETECTION := 0
+
# Byte alignment that each component in FIP is aligned to
FIP_ALIGN := 0