Merge changes from topic "feat_state_rework" into integration

* changes:
  feat(fvp): enable FEAT_HCX by default
  refactor(context-mgmt): move FEAT_HCX save/restore into C
  refactor(cpufeat): convert FEAT_HCX to new scheme
  feat(fvp): enable FEAT_FGT by default
  refactor(context-mgmt): move FEAT_FGT save/restore code into C
  refactor(amu): convert FEAT_AMUv1 to new scheme
  refactor(cpufeat): decouple FGT feature detection and build flags
  refactor(cpufeat): check FEAT_FGT in a new way
  refactor(cpufeat): move helpers into .c file, rename FEAT_STATE_
  feat(aarch64): make ID system register reads non-volatile

Author: manish-pandey-arm

bl31/bl31_main.c

@@ -93,15 +93,6 @@ void bl31_setup(u_register_t arg0, u_register_t arg1, u_register_t arg2,
 	/* Perform late platform-specific setup */
 	bl31_plat_arch_setup();
 
-#if ENABLE_FEAT_HCX
-	/*
-	 * Assert that FEAT_HCX is supported on this system, without this check
-	 * an exception would occur during context save/restore if enabled but
-	 * not supported.
-	 */
-	assert(is_feat_hcx_present());
-#endif /* ENABLE_FEAT_HCX */
-
 #if CTX_INCLUDE_PAUTH_REGS
 	/*
 	 * Assert that the ARMv8.3-PAuth registers are present or an access

changelog.yaml

@@ -101,6 +101,9 @@ subsections:
       - title: Extended Cache Index (FEAT_CCIDX)
         scope: ccidx
 
+      - title: CPU feature / ID register handling in general
+        scope: cpufeat
+
       - title: Support for the `HCRX_EL2` register (FEAT_HCX)
         scope: hcx
 

common/feat_detect.c

@@ -4,24 +4,59 @@
  * SPDX-License-Identifier: BSD-3-Clause
  */
 
+#include <arch_features.h>
+#include <common/debug.h>
 #include <common/feat_detect.h>
 
+static bool tainted;
+
 /*******************************************************************************
  * This section lists the wrapper modules for each feature to evaluate the
- * feature states (FEAT_STATE_1 and FEAT_STATE_2) and perform necessary action
- * as below:
+ * feature states (FEAT_STATE_ALWAYS and FEAT_STATE_CHECK) and perform
+ * necessary action as below:
  *
  * It verifies whether the FEAT_XXX (eg: FEAT_SB) is supported by the PE or not.
  * Without this check an exception would occur during context save/restore
  * routines, if the feature is enabled but not supported by PE.
  ******************************************************************************/
 
+#define feat_detect_panic(a, b)		((a) ? (void)0 : feature_panic(b))
+
+/*******************************************************************************
+ * Function : feature_panic
+ * Customised panic function with error logging mechanism to list the feature
+ * not supported by the PE.
+ ******************************************************************************/
+static inline void feature_panic(char *feat_name)
+{
+	ERROR("FEAT_%s not supported by the PE\n", feat_name);
+	panic();
+}
+
+/*******************************************************************************
+ * Function : check_feature
+ * Check for a valid combination of build time flags (ENABLE_FEAT_xxx) and
+ * feature availability on the hardware.
+ * Panics if a feature is forcefully enabled, but not available on the PE.
+ *
+ * We force inlining here to let the compiler optimise away the whole check
+ * if the feature is disabled at build time (FEAT_STATE_DISABLED).
+ ******************************************************************************/
+static inline void __attribute((__always_inline__))
+check_feature(int state, unsigned long field, const char *feat_name)
+{
+	if (state == FEAT_STATE_ALWAYS && field == 0U) {
+		ERROR("FEAT_%s not supported by the PE\n", feat_name);
+		tainted = true;
+	}
+}
+
 /******************************************
  * Feature : FEAT_SB (Speculation Barrier)
  *****************************************/
 static void read_feat_sb(void)
 {
-#if (ENABLE_FEAT_SB == FEAT_STATE_1)
+#if (ENABLE_FEAT_SB == FEAT_STATE_ALWAYS)
 	feat_detect_panic(is_armv8_0_feat_sb_present(), "SB");
 #endif
 }
@@ -31,7 +66,7 @@ static void read_feat_sb(void)
  *****************************************************/
 static void read_feat_csv2_2(void)
 {
-#if (ENABLE_FEAT_CSV2_2 == FEAT_STATE_1)
+#if (ENABLE_FEAT_CSV2_2 == FEAT_STATE_ALWAYS)
 	feat_detect_panic(is_armv8_0_feat_csv2_2_present(), "CSV2_2");
 #endif
 }
@@ -41,7 +76,7 @@ static void read_feat_csv2_2(void)
  **********************************************/
 static void read_feat_pan(void)
 {
-#if (ENABLE_FEAT_PAN == FEAT_STATE_1)
+#if (ENABLE_FEAT_PAN == FEAT_STATE_ALWAYS)
 	feat_detect_panic(is_armv8_1_pan_present(), "PAN");
 #endif
 }
@@ -51,7 +86,7 @@ static void read_feat_pan(void)
  *****************************************************/
 static void read_feat_vhe(void)
 {
-#if (ENABLE_FEAT_VHE == FEAT_STATE_1)
+#if (ENABLE_FEAT_VHE == FEAT_STATE_ALWAYS)
 	feat_detect_panic(is_armv8_1_vhe_present(), "VHE");
 #endif
 }
@@ -61,7 +96,7 @@ static void read_feat_vhe(void)
  ******************************************************************************/
 static void read_feat_ras(void)
 {
-#if (RAS_EXTENSION == FEAT_STATE_1)
+#if (RAS_EXTENSION == FEAT_STATE_ALWAYS)
 	feat_detect_panic(is_armv8_2_feat_ras_present(), "RAS");
 #endif
 }
@@ -71,7 +106,7 @@ static void read_feat_ras(void)
  ***********************************************/
 static void read_feat_pauth(void)
 {
-#if (ENABLE_PAUTH == FEAT_STATE_1) || (CTX_INCLUDE_PAUTH_REGS == FEAT_STATE_1)
+#if (ENABLE_PAUTH == FEAT_STATE_ALWAYS) || (CTX_INCLUDE_PAUTH_REGS == FEAT_STATE_ALWAYS)
 	feat_detect_panic(is_armv8_3_pauth_present(), "PAUTH");
 #endif
 }
@@ -81,27 +116,17 @@ static void read_feat_pauth(void)
  ***********************************************************/
 static void read_feat_dit(void)
 {
-#if (ENABLE_FEAT_DIT == FEAT_STATE_1)
+#if (ENABLE_FEAT_DIT == FEAT_STATE_ALWAYS)
 	feat_detect_panic(is_armv8_4_feat_dit_present(), "DIT");
 #endif
 }
 
-/*********************************************************
- * Feature : FEAT_AMUv1 (Activity Monitors Extensions v1)
- ********************************************************/
-static void read_feat_amuv1(void)
-{
-#if (ENABLE_FEAT_AMUv1 == FEAT_STATE_1)
-	feat_detect_panic(is_armv8_4_feat_amuv1_present(), "AMUv1");
-#endif
-}
-
 /****************************************************************************
  * Feature : FEAT_MPAM (Memory Partitioning and Monitoring (MPAM) Extension)
  ***************************************************************************/
 static void read_feat_mpam(void)
 {
-#if (ENABLE_MPAM_FOR_LOWER_ELS == FEAT_STATE_1)
+#if (ENABLE_MPAM_FOR_LOWER_ELS == FEAT_STATE_ALWAYS)
 	feat_detect_panic(get_mpam_version() != 0U, "MPAM");
 #endif
 }
@@ -111,7 +136,7 @@ static void read_feat_mpam(void)
  *************************************************************/
 static void read_feat_nv2(void)
 {
-#if (CTX_INCLUDE_NEVE_REGS == FEAT_STATE_1)
+#if (CTX_INCLUDE_NEVE_REGS == FEAT_STATE_ALWAYS)
 	unsigned int nv = get_armv8_4_feat_nv_support();
 
 	feat_detect_panic((nv == ID_AA64MMFR2_EL1_NV2_SUPPORTED), "NV2");
@@ -123,7 +148,7 @@ static void read_feat_nv2(void)
  **********************************/
 static void read_feat_sel2(void)
 {
-#if (ENABLE_FEAT_SEL2 == FEAT_STATE_1)
+#if (ENABLE_FEAT_SEL2 == FEAT_STATE_ALWAYS)
 	feat_detect_panic(is_armv8_4_sel2_present(), "SEL2");
 #endif
 }
@@ -133,7 +158,7 @@ static void read_feat_sel2(void)
  ***************************************************/
 static void read_feat_trf(void)
 {
-#if (ENABLE_TRF_FOR_NS == FEAT_STATE_1)
+#if (ENABLE_TRF_FOR_NS == FEAT_STATE_ALWAYS)
 	feat_detect_panic(is_arm8_4_feat_trf_present(), "TRF");
 #endif
 }
@@ -143,7 +168,7 @@ static void read_feat_trf(void)
  ***********************************************/
 static void read_feat_mte(void)
 {
-#if (CTX_INCLUDE_MTE_REGS == FEAT_STATE_1)
+#if (CTX_INCLUDE_MTE_REGS == FEAT_STATE_ALWAYS)
 	unsigned int mte = get_armv8_5_mte_support();
 
 	feat_detect_panic((mte != MTE_UNIMPLEMENTED), "MTE");
@@ -155,7 +180,7 @@ static void read_feat_mte(void)
  **********************************************/
 static void read_feat_rng(void)
 {
-#if (ENABLE_FEAT_RNG == FEAT_STATE_1)
+#if (ENABLE_FEAT_RNG == FEAT_STATE_ALWAYS)
 	feat_detect_panic(is_armv8_5_rng_present(), "RNG");
 #endif
 }
@@ -165,27 +190,17 @@ static void read_feat_rng(void)
  ***************************************************/
 static void read_feat_bti(void)
 {
-#if (ENABLE_BTI == FEAT_STATE_1)
+#if (ENABLE_BTI == FEAT_STATE_ALWAYS)
 	feat_detect_panic(is_armv8_5_bti_present(), "BTI");
 #endif
 }
 
-/****************************************
- * Feature : FEAT_FGT (Fine Grain Traps)
- ***************************************/
-static void read_feat_fgt(void)
-{
-#if (ENABLE_FEAT_FGT == FEAT_STATE_1)
-	feat_detect_panic(is_armv8_6_fgt_present(), "FGT");
-#endif
-}
-
 /***********************************************
  * Feature : FEAT_AMUv1p1 (AMU Extensions v1.1)
  **********************************************/
 static void read_feat_amuv1p1(void)
 {
-#if (ENABLE_FEAT_AMUv1p1 == FEAT_STATE_1)
+#if (ENABLE_FEAT_AMUv1p1 == FEAT_STATE_ALWAYS)
 	feat_detect_panic(is_armv8_6_feat_amuv1p1_present(), "AMUv1p1");
 #endif
 }
@@ -195,7 +210,7 @@ static void read_feat_amuv1p1(void)
  ******************************************************/
 static void read_feat_ecv(void)
 {
-#if (ENABLE_FEAT_ECV == FEAT_STATE_1)
+#if (ENABLE_FEAT_ECV == FEAT_STATE_ALWAYS)
 	unsigned int ecv = get_armv8_6_ecv_support();
 
 	feat_detect_panic(((ecv == ID_AA64MMFR0_EL1_ECV_SUPPORTED) ||
@@ -208,27 +223,17 @@ static void read_feat_ecv(void)
  **********************************************************/
 static void read_feat_twed(void)
 {
-#if (ENABLE_FEAT_TWED == FEAT_STATE_1)
+#if (ENABLE_FEAT_TWED == FEAT_STATE_ALWAYS)
 	feat_detect_panic(is_armv8_6_twed_present(), "TWED");
 #endif
 }
 
-/******************************************************************
- * Feature : FEAT_HCX (Extended Hypervisor Configuration Register)
- *****************************************************************/
-static void read_feat_hcx(void)
-{
-#if (ENABLE_FEAT_HCX == FEAT_STATE_1)
-	feat_detect_panic(is_feat_hcx_present(), "HCX");
-#endif
-}
-
 /**************************************************
  * Feature : FEAT_RME (Realm Management Extension)
  *************************************************/
 static void read_feat_rme(void)
 {
-#if (ENABLE_RME == FEAT_STATE_1)
+#if (ENABLE_RME == FEAT_STATE_ALWAYS)
 	feat_detect_panic((get_armv9_2_feat_rme_support() !=
 			ID_AA64PFR0_FEAT_RME_NOT_SUPPORTED), "RME");
 #endif
@@ -239,7 +244,7 @@ static void read_feat_rme(void)
  *****************************************************/
 static void read_feat_brbe(void)
 {
-#if (ENABLE_BRBE_FOR_NS == FEAT_STATE_1)
+#if (ENABLE_BRBE_FOR_NS == FEAT_STATE_ALWAYS)
 	feat_detect_panic(is_feat_brbe_present(), "BRBE");
 #endif
 }
@@ -249,7 +254,7 @@ static void read_feat_brbe(void)
  *****************************************************/
 static void read_feat_trbe(void)
 {
-#if (ENABLE_TRBE_FOR_NS == FEAT_STATE_1)
+#if (ENABLE_TRBE_FOR_NS == FEAT_STATE_ALWAYS)
 	feat_detect_panic(is_feat_trbe_present(), "TRBE");
 #endif
 }
@@ -259,7 +264,7 @@ static void read_feat_trbe(void)
  *****************************************************************/
 static void read_feat_rng_trap(void)
 {
-#if (ENABLE_FEAT_RNG_TRAP == FEAT_STATE_1)
+#if (ENABLE_FEAT_RNG_TRAP == FEAT_STATE_ALWAYS)
 	feat_detect_panic(is_feat_rng_trap_present(), "RNG_TRAP");
 #endif
 }
@@ -283,11 +288,14 @@ static void read_feat_rng_trap(void)
  * ENABLE_FEAT_xxx = 2 : The feature is enabled but dynamically enabled at runtime
  *                       depending on hardware capability.
  *
- * For better readability, state values are defined with macros namely:
- * { FEAT_STATE_0, FEAT_STATE_1, FEAT_STATE_2 } taking values as their naming.
+ * For better readability, state values are defined with macros, namely:
+ * { FEAT_STATE_DISABLED, FEAT_STATE_ALWAYS, FEAT_STATE_CHECK }, taking values
+ * { 0, 1, 2 }, respectively, as their naming.
  **********************************************************************************/
 void detect_arch_features(void)
 {
+	tainted = false;
+
 	/* v8.0 features */
 	read_feat_sb();
 	read_feat_csv2_2();
@@ -304,7 +312,7 @@ void detect_arch_features(void)
 
 	/* v8.4 features */
 	read_feat_dit();
-	read_feat_amuv1();
+	check_feature(ENABLE_FEAT_AMUv1, read_feat_amu_id_field(), "AMUv1");
 	read_feat_mpam();
 	read_feat_nv2();
 	read_feat_sel2();
@@ -318,17 +326,21 @@ void detect_arch_features(void)
 
 	/* v8.6 features */
 	read_feat_amuv1p1();
-	read_feat_fgt();
+	check_feature(ENABLE_FEAT_FGT, read_feat_fgt_id_field(), "FGT");
 	read_feat_ecv();
 	read_feat_twed();
 
 	/* v8.7 features */
-	read_feat_hcx();
+	check_feature(ENABLE_FEAT_HCX, read_feat_hcx_id_field(), "HCX");
 
 	/* v9.0 features */
 	read_feat_brbe();
 	read_feat_trbe();
 
 	/* v9.2 features */
 	read_feat_rme();
+
+	if (tainted) {
+		panic();
+	}
 }