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/common/feat_detect.c b/common/feat_detect.c
new file mode 100644
index 0000000..ef09b86
--- /dev/null
+++ b/common/feat_detect.c
@@ -0,0 +1,288 @@
+/*
+ * Copyright (c) 2022, Arm Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <common/feat_detect.h>
+
+/*******************************************************************************
+ * 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:
+ *
+ * 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.
+ ******************************************************************************/
+
+/******************************************
+ * Feature : FEAT_SB (Speculation Barrier)
+ *****************************************/
+static void read_feat_sb(void)
+{
+#if (ENABLE_FEAT_SB == FEAT_STATE_1)
+ feat_detect_panic(is_armv8_0_feat_sb_present(), "SB");
+#endif
+}
+
+/******************************************************
+ * Feature : FEAT_CSV2_2 (Cache Speculation Variant 2)
+ *****************************************************/
+static void read_feat_csv2_2(void)
+{
+#if (ENABLE_FEAT_CSV2_2 == FEAT_STATE_1)
+ feat_detect_panic(is_armv8_0_feat_csv2_2_present(), "CSV2_2");
+#endif
+}
+
+/***********************************************
+ * Feature : FEAT_PAN (Privileged Access Never)
+ **********************************************/
+static void read_feat_pan(void)
+{
+#if (ENABLE_FEAT_PAN == FEAT_STATE_1)
+ feat_detect_panic(is_armv8_1_pan_present(), "PAN");
+#endif
+}
+
+/******************************************************
+ * Feature : FEAT_VHE (Virtualization Host Extensions)
+ *****************************************************/
+static void read_feat_vhe(void)
+{
+#if (ENABLE_FEAT_VHE == FEAT_STATE_1)
+ feat_detect_panic(is_armv8_1_vhe_present(), "VHE");
+#endif
+}
+
+/*******************************************************************************
+ * Feature : FEAT_RAS (Reliability, Availability, and Serviceability Extension)
+ ******************************************************************************/
+static void read_feat_ras(void)
+{
+#if (RAS_EXTENSION == FEAT_STATE_1)
+ feat_detect_panic(is_armv8_2_feat_ras_present(), "RAS");
+#endif
+}
+
+/************************************************
+ * Feature : FEAT_PAUTH (Pointer Authentication)
+ ***********************************************/
+static void read_feat_pauth(void)
+{
+#if (ENABLE_PAUTH == FEAT_STATE_1) || (CTX_INCLUDE_PAUTH_REGS == FEAT_STATE_1)
+ feat_detect_panic(is_armv8_3_pauth_present(), "PAUTH");
+#endif
+}
+
+/************************************************************
+ * Feature : FEAT_DIT (Data Independent Timing Instructions)
+ ***********************************************************/
+static void read_feat_dit(void)
+{
+#if (ENABLE_FEAT_DIT == FEAT_STATE_1)
+ 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)
+ feat_detect_panic(get_mpam_version() != 0U, "MPAM");
+#endif
+}
+
+/**************************************************************
+ * Feature : FEAT_NV2 (Enhanced Nested Virtualization Support)
+ *************************************************************/
+static void read_feat_nv2(void)
+{
+#if (CTX_INCLUDE_NEVE_REGS == FEAT_STATE_1)
+ unsigned int nv = get_armv8_4_feat_nv_support();
+
+ feat_detect_panic((nv == ID_AA64MMFR2_EL1_NV2_SUPPORTED), "NV2");
+#endif
+}
+
+/***********************************
+ * Feature : FEAT_SEL2 (Secure EL2)
+ **********************************/
+static void read_feat_sel2(void)
+{
+#if (ENABLE_FEAT_SEL2 == FEAT_STATE_1)
+ feat_detect_panic(is_armv8_4_sel2_present(), "SEL2");
+#endif
+}
+
+/****************************************************
+ * Feature : FEAT_TRF (Self-hosted Trace Extensions)
+ ***************************************************/
+static void read_feat_trf(void)
+{
+#if (ENABLE_TRF_FOR_NS == FEAT_STATE_1)
+ feat_detect_panic(is_arm8_4_feat_trf_present(), "TRF");
+#endif
+}
+
+/************************************************
+ * Feature : FEAT_MTE (Memory Tagging Extension)
+ ***********************************************/
+static void read_feat_mte(void)
+{
+#if (CTX_INCLUDE_MTE_REGS == FEAT_STATE_1)
+ unsigned int mte = get_armv8_5_mte_support();
+
+ feat_detect_panic((mte != MTE_UNIMPLEMENTED), "MTE");
+#endif
+}
+
+/***********************************************
+ * Feature : FEAT_RNG (Random Number Generator)
+ **********************************************/
+static void read_feat_rng(void)
+{
+#if (ENABLE_FEAT_RNG == FEAT_STATE_1)
+ feat_detect_panic(is_armv8_5_rng_present(), "RNG");
+#endif
+}
+
+/****************************************************
+ * Feature : FEAT_BTI (Branch Target Identification)
+ ***************************************************/
+static void read_feat_bti(void)
+{
+#if (ENABLE_BTI == FEAT_STATE_1)
+ 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)
+ feat_detect_panic(is_armv8_6_feat_amuv1p1_present(), "AMUv1p1");
+#endif
+}
+
+/*******************************************************
+ * Feature : FEAT_ECV (Enhanced Counter Virtualization)
+ ******************************************************/
+static void read_feat_ecv(void)
+{
+#if (ENABLE_FEAT_ECV == FEAT_STATE_1)
+ unsigned int ecv = get_armv8_6_ecv_support();
+
+ feat_detect_panic(((ecv == ID_AA64MMFR0_EL1_ECV_SUPPORTED) ||
+ (ecv == ID_AA64MMFR0_EL1_ECV_SELF_SYNCH)), "ECV");
+#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)
+ feat_detect_panic((get_armv9_2_feat_rme_support() !=
+ ID_AA64PFR0_FEAT_RME_NOT_SUPPORTED), "RME");
+#endif
+}
+
+/***********************************************************************************
+ * TF-A supports many Arm architectural features starting from arch version
+ * (8.0 till 8.7+). These features are mostly enabled through build flags. This
+ * mechanism helps in validating these build flags in the early boot phase
+ * either in BL1 or BL31 depending on the platform and assists in identifying
+ * and notifying the features which are enabled but not supported by the PE.
+ *
+ * It reads all the enabled features ID-registers and ensures the features
+ * are supported by the PE.
+ * In case if they aren't it stops booting at an early phase and logs the error
+ * messages, notifying the platforms about the features that are not supported.
+ *
+ * Further the procedure is implemented with a tri-state approach for each feature:
+ * ENABLE_FEAT_xxx = 0 : The feature is disabled statically at compile time
+ * ENABLE_FEAT_xxx = 1 : The feature is enabled and must be present in hardware.
+ * There will be panic if feature is not present at cold boot.
+ * 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.
+ **********************************************************************************/
+void detect_arch_features(void)
+{
+ /* v8.0 features */
+ read_feat_sb();
+ read_feat_csv2_2();
+
+ /* v8.1 features */
+ read_feat_pan();
+ read_feat_vhe();
+
+ /* v8.2 features */
+ read_feat_ras();
+
+ /* v8.3 features */
+ read_feat_pauth();
+
+ /* v8.4 features */
+ read_feat_dit();
+ read_feat_amuv1();
+ read_feat_mpam();
+ read_feat_nv2();
+ read_feat_sel2();
+ read_feat_trf();
+
+ /* v8.5 features */
+ read_feat_mte();
+ read_feat_rng();
+ read_feat_bti();
+
+ /* v8.6 features */
+ read_feat_amuv1p1();
+ read_feat_fgt();
+ read_feat_ecv();
+
+ /* v8.7 features */
+ read_feat_hcx();
+
+ /* v9.2 features */
+ read_feat_rme();
+}