platform-switcher_cpu_features.inc

// Copyright SCI Semiconductor and CHERIoT Contributors.
// SPDX-License-Identifier: MIT
 
#pragma once
 
#include "platform-switcher_cpu_features.hh"
 
/// A mask of all bits that can be set in cpuFeatures
#   define SWITCHER_CPU_FEATURE_PLATFORM_MASK                                 \
        (IbexCSR_Cpuctrlsts_IcacheEnable |                                     \
         IbexCSR_Cpuctrlsts_DataIndependentTiming)
 
// clang-format off
 
.macro platform_switcher_cpu_features_activate newValue, scratch
    // Mask out bits not available for user control
    andi               \newValue, \newValue, SWITCHER_CPU_FEATURE_PLATFORM_MASK
 
    // OR those in with the other bits in the register and write
    csrr               \scratch, IbexCSR_Cpuctrlsts_index
    andi               \scratch, \scratch, ~SWITCHER_CPU_FEATURE_PLATFORM_MASK
    or                 \scratch, \scratch, \newValue
    csrw               IbexCSR_Cpuctrlsts_index, \scratch
 
    // Read back the bits available for user control
    csrr               \newValue, IbexCSR_Cpuctrlsts_index
    andi               \newValue, \newValue, SWITCHER_CPU_FEATURE_PLATFORM_MASK
.endm
 
.macro platform_switcher_cpu_features_reactivate newValue, scratch
    // newValue is known to be masked, so just RMW the CSR
    csrr               \scratch, IbexCSR_Cpuctrlsts_index
    andi               \scratch, \scratch, ~SWITCHER_CPU_FEATURE_PLATFORM_MASK
    or                 \scratch, \scratch, \newValue
    csrw               IbexCSR_Cpuctrlsts_index, \scratch
.endm
 
// clang-format on