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arm-trusted-firmware/common/feat_detect.c

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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
3 years ago
/*
* 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
}
refactor(twed): improve TWED enablement in EL-3 The current implementation uses plat_arm API under generic code. &#34;plat_arm&#34; API is a convention used with Arm common platform layer and is reserved for that purpose. In addition, the function has a weak definition which is not encouraged in TF-A. Henceforth, removing the weak API with a configurable macro &#34;TWED_DELAY&#34; of numeric data type in generic code and simplifying the implementation. By default &#34;TWED_DELAY&#34; is defined to zero, and the delay value need to be explicitly set by the platforms during buildtime. Signed-off-by: Jayanth Dodderi Chidanand &lt;jayanthdodderi.chidanand@arm.com&gt; Change-Id: I25cd6f628e863dc40415ced3a82d0662fdf2d75a
3 years ago
/***********************************************************
* Feature : FEAT_TWED (Delayed Trapping of WFE Instruction)
**********************************************************/
static void read_feat_twed(void)
{
#if (ENABLE_FEAT_TWED == FEAT_STATE_1)
feat_detect_panic(is_armv8_6_twed_present(), "TWED");
#endif
}
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 &#34;FEATURE_DETECTION&#34;, which is currently being disabled by default. The &#34;FEATURE_DETECTION&#34; macro is documented and the platforms are encouraged to make use of this diagnostic tool by enabling this &#34;FEATURE_DETECTION&#34; flag explicitly and get used to its behaviour during booting before the procedure gets mandated. Signed-off-by: Jayanth Dodderi Chidanand &lt;jayanthdodderi.chidanand@arm.com&gt; Change-Id: Ia23d95430fe82d417a938b672bfb5edc401b0f43
3 years ago
/******************************************************************
* 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
}
feat(brbe): add brbe under feature detection mechanism This change adds &#34;FEAT_BRBE&#34; to be part of feature detection mechanism. Previously feature enablement flags were of boolean type, possessing either 0 or 1. With the introduction of feature detection procedure we now support three states for feature enablement build flags(0 to 2). Accordingly, &#34;ENABLE_BRBE_FOR_NS&#34; flag is now modified from boolean to numeric type to align with the feature detection. Signed-off-by: Jayanth Dodderi Chidanand &lt;jayanthdodderi.chidanand@arm.com&gt; Change-Id: I1eb52863b4afb10b808e2f0b6584a8a210d0f38c
3 years ago
/******************************************************
* Feature : FEAT_BRBE (Branch Record Buffer Extension)
*****************************************************/
static void read_feat_brbe(void)
{
#if (ENABLE_BRBE_FOR_NS == FEAT_STATE_1)
feat_detect_panic(is_feat_brbe_present(), "BRBE");
#endif
}
feat(trbe): add trbe under feature detection mechanism This change adds &#34;FEAT_TRBE&#34; to be part of feature detection mechanism. Previously feature enablement flags were of boolean type, containing either 0 or 1. With the introduction of feature detection procedure we now support three states for feature enablement build flags(0 to 2). Accordingly, &#34;ENABLE_TRBE_FOR_NS&#34; flag is now modified from boolean to numeric type to align with the feature detection. Change-Id: I53d3bc8dc2f6eac63feef22dfd627f3a48480afc Signed-off-by: Jayanth Dodderi Chidanand &lt;jayanthdodderi.chidanand@arm.com&gt;
3 years ago
/******************************************************
* Feature : FEAT_TRBE (Trace Buffer Extension)
*****************************************************/
static void read_feat_trbe(void)
{
#if (ENABLE_TRBE_FOR_NS == FEAT_STATE_1)
feat_detect_panic(is_feat_trbe_present(), "TRBE");
#endif
}
feat(rng-trap): add EL3 support for FEAT_RNG_TRAP FEAT_RNG_TRAP introduces support for EL3 trapping of reads of the RNDR and RNDRRS registers, which is enabled by setting the SCR_EL3.TRNDR bit. This patch adds a new build flag ENABLE_FEAT_RNG_TRAP that enables the feature. This feature is supported only in AArch64 state from Armv8.5 onwards. Signed-off-by: Juan Pablo Conde &lt;juanpablo.conde@arm.com&gt; Change-Id: Ia9f17aef3444d3822bf03809036a1f668c9f2d89
2 years ago
/******************************************************************
* Feature : FEAT_RNG_TRAP (Trapping support for RNDR/RNDRRS)
*****************************************************************/
static void read_feat_rng_trap(void)
{
#if (ENABLE_FEAT_RNG_TRAP == FEAT_STATE_1)
feat_detect_panic(is_feat_rng_trap_present(), "RNG_TRAP");
#endif
}
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 &#34;FEATURE_DETECTION&#34;, which is currently being disabled by default. The &#34;FEATURE_DETECTION&#34; macro is documented and the platforms are encouraged to make use of this diagnostic tool by enabling this &#34;FEATURE_DETECTION&#34; flag explicitly and get used to its behaviour during booting before the procedure gets mandated. Signed-off-by: Jayanth Dodderi Chidanand &lt;jayanthdodderi.chidanand@arm.com&gt; Change-Id: Ia23d95430fe82d417a938b672bfb5edc401b0f43
3 years ago
/***********************************************************************************
* 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();
feat(rng-trap): add EL3 support for FEAT_RNG_TRAP FEAT_RNG_TRAP introduces support for EL3 trapping of reads of the RNDR and RNDRRS registers, which is enabled by setting the SCR_EL3.TRNDR bit. This patch adds a new build flag ENABLE_FEAT_RNG_TRAP that enables the feature. This feature is supported only in AArch64 state from Armv8.5 onwards. Signed-off-by: Juan Pablo Conde &lt;juanpablo.conde@arm.com&gt; Change-Id: Ia9f17aef3444d3822bf03809036a1f668c9f2d89
2 years ago
read_feat_rng_trap();
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 &#34;FEATURE_DETECTION&#34;, which is currently being disabled by default. The &#34;FEATURE_DETECTION&#34; macro is documented and the platforms are encouraged to make use of this diagnostic tool by enabling this &#34;FEATURE_DETECTION&#34; flag explicitly and get used to its behaviour during booting before the procedure gets mandated. Signed-off-by: Jayanth Dodderi Chidanand &lt;jayanthdodderi.chidanand@arm.com&gt; Change-Id: Ia23d95430fe82d417a938b672bfb5edc401b0f43
3 years ago
/* v8.6 features */
read_feat_amuv1p1();
read_feat_fgt();
read_feat_ecv();
refactor(twed): improve TWED enablement in EL-3 The current implementation uses plat_arm API under generic code. &#34;plat_arm&#34; API is a convention used with Arm common platform layer and is reserved for that purpose. In addition, the function has a weak definition which is not encouraged in TF-A. Henceforth, removing the weak API with a configurable macro &#34;TWED_DELAY&#34; of numeric data type in generic code and simplifying the implementation. By default &#34;TWED_DELAY&#34; is defined to zero, and the delay value need to be explicitly set by the platforms during buildtime. Signed-off-by: Jayanth Dodderi Chidanand &lt;jayanthdodderi.chidanand@arm.com&gt; Change-Id: I25cd6f628e863dc40415ced3a82d0662fdf2d75a
3 years ago
read_feat_twed();
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 &#34;FEATURE_DETECTION&#34;, which is currently being disabled by default. The &#34;FEATURE_DETECTION&#34; macro is documented and the platforms are encouraged to make use of this diagnostic tool by enabling this &#34;FEATURE_DETECTION&#34; flag explicitly and get used to its behaviour during booting before the procedure gets mandated. Signed-off-by: Jayanth Dodderi Chidanand &lt;jayanthdodderi.chidanand@arm.com&gt; Change-Id: Ia23d95430fe82d417a938b672bfb5edc401b0f43
3 years ago
/* v8.7 features */
read_feat_hcx();
feat(brbe): add brbe under feature detection mechanism This change adds &#34;FEAT_BRBE&#34; to be part of feature detection mechanism. Previously feature enablement flags were of boolean type, possessing either 0 or 1. With the introduction of feature detection procedure we now support three states for feature enablement build flags(0 to 2). Accordingly, &#34;ENABLE_BRBE_FOR_NS&#34; flag is now modified from boolean to numeric type to align with the feature detection. Signed-off-by: Jayanth Dodderi Chidanand &lt;jayanthdodderi.chidanand@arm.com&gt; Change-Id: I1eb52863b4afb10b808e2f0b6584a8a210d0f38c
3 years ago
/* v9.0 features */
read_feat_brbe();
feat(trbe): add trbe under feature detection mechanism This change adds &#34;FEAT_TRBE&#34; to be part of feature detection mechanism. Previously feature enablement flags were of boolean type, containing either 0 or 1. With the introduction of feature detection procedure we now support three states for feature enablement build flags(0 to 2). Accordingly, &#34;ENABLE_TRBE_FOR_NS&#34; flag is now modified from boolean to numeric type to align with the feature detection. Change-Id: I53d3bc8dc2f6eac63feef22dfd627f3a48480afc Signed-off-by: Jayanth Dodderi Chidanand &lt;jayanthdodderi.chidanand@arm.com&gt;
3 years ago
read_feat_trbe();
feat(brbe): add brbe under feature detection mechanism This change adds &#34;FEAT_BRBE&#34; to be part of feature detection mechanism. Previously feature enablement flags were of boolean type, possessing either 0 or 1. With the introduction of feature detection procedure we now support three states for feature enablement build flags(0 to 2). Accordingly, &#34;ENABLE_BRBE_FOR_NS&#34; flag is now modified from boolean to numeric type to align with the feature detection. Signed-off-by: Jayanth Dodderi Chidanand &lt;jayanthdodderi.chidanand@arm.com&gt; Change-Id: I1eb52863b4afb10b808e2f0b6584a8a210d0f38c
3 years ago
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 &#34;FEATURE_DETECTION&#34;, which is currently being disabled by default. The &#34;FEATURE_DETECTION&#34; macro is documented and the platforms are encouraged to make use of this diagnostic tool by enabling this &#34;FEATURE_DETECTION&#34; flag explicitly and get used to its behaviour during booting before the procedure gets mandated. Signed-off-by: Jayanth Dodderi Chidanand &lt;jayanthdodderi.chidanand@arm.com&gt; Change-Id: Ia23d95430fe82d417a938b672bfb5edc401b0f43
3 years ago
/* v9.2 features */
read_feat_rme();
}