refactor(cpufeat): enable FEAT_CSV2_2 for FEAT_STATE_CHECKED
At the moment we only support FEAT_CSV2_2 to be either unconditionally
compiled in, or to be not supported at all.
Add support for runtime detection (ENABLE_FEAT_CSV2_2=2), by splitting
is_armv8_0_feat_csv2_2_present() into an ID register reading function
and a second function to report the support status. That function
considers both build time settings and runtime information (if needed),
and is used before we access the SCXTNUM_EL2 system register.
Also move the context saving code from assembly to C, and use the new
is_feat_csv2_2_supported() function to guard its execution.
Change the FVP platform default to the now supported dynamic option (=2),
so the right decision can be made by the code at runtime.
Change-Id: I89c7bc883e6a65727fdbdd36eb3bfbffb2196da7
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
diff --git a/include/arch/aarch64/arch_features.h b/include/arch/aarch64/arch_features.h
index 029cdd1..0342d2f 100644
--- a/include/arch/aarch64/arch_features.h
+++ b/include/arch/aarch64/arch_features.h
@@ -301,10 +301,22 @@
/*********************************************************************************
* Function to identify the presence of FEAT_CSV2_2 (Cache Speculation Variant 2)
********************************************************************************/
-static inline bool is_armv8_0_feat_csv2_2_present(void)
+static inline unsigned int read_feat_csv2_id_field(void)
+{
+ return ISOLATE_FIELD(read_id_aa64pfr0_el1(), ID_AA64PFR0_CSV2);
+}
+
+static inline bool is_feat_csv2_2_supported(void)
{
- return (((read_id_aa64pfr0_el1() >> ID_AA64PFR0_CSV2_SHIFT) &
- ID_AA64PFR0_CSV2_MASK) == ID_AA64PFR0_CSV2_2_SUPPORTED);
+ if (ENABLE_FEAT_CSV2_2 == FEAT_STATE_DISABLED) {
+ return false;
+ }
+
+ if (ENABLE_FEAT_CSV2_2 == FEAT_STATE_ALWAYS) {
+ return true;
+ }
+
+ return read_feat_csv2_id_field() >= ID_AA64PFR0_CSV2_2_SUPPORTED;
}
/**********************************************************************************