refactor(cpufeat): decouple FGT feature detection and build flags
Split the feature check for FEAT_FGT into two parts:
- A boolean function that just evaluates whether the feature is usable.
This takes build time flags into account, and only evaluates the CPU
feature ID registers when the flexible FEAT_STATE_CHECK method is
used.
- A "raw" function that returns the unfiltered CPU feature ID register.
Change the callers where needed, to give them the version they actually
want.
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Change-Id: I9a041132d280451f5d9f653a62904f603b2a916d
diff --git a/common/feat_detect.c b/common/feat_detect.c
index 21dd35d..cbbee97 100644
--- a/common/feat_detect.c
+++ b/common/feat_detect.c
@@ -346,7 +346,7 @@
/* v8.6 features */
read_feat_amuv1p1();
- check_feature(ENABLE_FEAT_FGT, is_armv8_6_fgt_present(), "FGT");
+ check_feature(ENABLE_FEAT_FGT, read_feat_fgt_id_field(), "FGT");
read_feat_ecv();
read_feat_twed();
diff --git a/include/arch/aarch64/arch_features.h b/include/arch/aarch64/arch_features.h
index 932e885..73dfcef 100644
--- a/include/arch/aarch64/arch_features.h
+++ b/include/arch/aarch64/arch_features.h
@@ -10,6 +10,7 @@
#include <stdbool.h>
#include <arch_helpers.h>
+#include <common/feat_detect.h>
static inline bool is_armv7_gentimer_present(void)
{
@@ -97,10 +98,23 @@
ID_AA64MMFR1_EL1_TWED_MASK) == ID_AA64MMFR1_EL1_TWED_SUPPORTED);
}
-static inline bool is_armv8_6_fgt_present(void)
+static unsigned int read_feat_fgt_id_field(void)
{
- return ((read_id_aa64mmfr0_el1() >> ID_AA64MMFR0_EL1_FGT_SHIFT) &
- ID_AA64MMFR0_EL1_FGT_MASK) != 0U;
+ return (read_id_aa64mmfr0_el1() >> ID_AA64MMFR0_EL1_FGT_SHIFT) &
+ ID_AA64MMFR0_EL1_FGT_MASK;
+}
+
+static inline bool is_feat_fgt_supported(void)
+{
+ if (ENABLE_FEAT_FGT == FEAT_STATE_DISABLED) {
+ return false;
+ }
+
+ if (ENABLE_FEAT_FGT == FEAT_STATE_ALWAYS) {
+ return true;
+ }
+
+ return read_feat_fgt_id_field() != 0U;
}
static inline unsigned long int get_armv8_6_ecv_support(void)
diff --git a/lib/el3_runtime/aarch64/context_mgmt.c b/lib/el3_runtime/aarch64/context_mgmt.c
index 866ac41..93d817f 100644
--- a/lib/el3_runtime/aarch64/context_mgmt.c
+++ b/lib/el3_runtime/aarch64/context_mgmt.c
@@ -359,7 +359,7 @@
&& (GET_M32(ep->spsr) == MODE32_hyp))) {
scr_el3 |= SCR_HCE_BIT;
- if (is_armv8_6_fgt_present()) {
+ if (is_feat_fgt_supported()) {
scr_el3 |= SCR_FGTEN_BIT;
}