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arm-trusted-firmware/include/common/feat_detect.h

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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
*/
#ifndef FEAT_DETECT_H
#define FEAT_DETECT_H
/* Function Prototypes */
void detect_arch_features(void);
/* Macro Definitions */
feat(cpufeat): add new feature state for asymmetric features Introduce a new feature state CHECK_ASYMMETRIC to cater for the features which are asymmetric across cores. This state is useful for platforms which has architectural asymmetric cores (A feature is only present in one type of core e.g. big). This state is similar to FEAT_STATE_CHECK (dynamic detection) except that feature state is also checked on each core during warmboot path and override the context (just for asymmetric features) which was setup by core executing CPU_ON call. Only Non-secure context will be re-checked as secure and realm context is created on same core. Signed-off-by: Manish Pandey <manish.pandey2@arm.com> Change-Id: Ic78a0b6ca996e0d7881c43da1a6a0c422f528ef3
4 months ago
#define FEAT_STATE_DISABLED 0
#define FEAT_STATE_ALWAYS 1
#define FEAT_STATE_CHECK 2
#define FEAT_STATE_CHECK_ASYMMETRIC 3
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
#endif /* FEAT_DETECT_H */