stk_arch_arm-cortex-m.h

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/*
 * SuperTinyKernel(TM) RTOS: Lightweight High-Performance Deterministic C++ RTOS for Embedded Systems.
 *
 * Source: https://github.com/SuperTinyKernel-RTOS
 *
 * Copyright (c) 2022-2026 Neutron Code Limited <stk@neutroncode.com>. All Rights Reserved.
 * License: MIT License, see LICENSE for a full text.
 */
 
#ifndef STK_ARCH_ARM_CORTEX_M_H_
#define STK_ARCH_ARM_CORTEX_M_H_
 
#include "stk_common.h"
#if defined(__ARM_FEATURE_CMSE) && (__ARM_FEATURE_CMSE != 0)
    #include <arm_cmse.h> // for ARM TrustZone
#endif

 
namespace stk {

class PlatformArmCortexM final : public IPlatform
{
public:
    STK_VIRT_DTOR ~PlatformArmCortexM() = default;
 
    void Initialize(IEventHandler *event_handler, IKernelService *service, uint32_t resolution_us, Stack *exit_trap) override;
    void Start() override;
    void Stop() override;
    void InitStack(EStackType stack_type, Stack *stack, IStackMemory *stack_memory, ITask *user_task) override;
    uint32_t GetTickResolution() const override;
    Cycles GetSysTimerCount() const override;
    uint32_t GetSysTimerFrequency() const override;
    void SwitchToNext() override;
    void Sleep(Timeout ticks) override;
    bool SleepUntil(Ticks timestamp) override;
    EWaitResult Wait(ISyncObject *sync_obj, IMutex *mutex, Timeout timeout) override;
    void ProcessTick() override;
    void ProcessHardFault() override;
    void SetEventOverrider(IEventOverrider *overrider) override;
    Word GetCallerSP() const override;
    TId GetTid() const override;
    Timeout Suspend() override;
    void Resume(Timeout elapsed_ticks) override;
};

typedef PlatformArmCortexM PlatformDefault;
 
// Inline TLS via r9. Active when both STK_TLS and STK_TLS_PREFER_REGISTER are
// enabled. Requires -ffixed-r9 on all translation units containing task code
// (see GetTls/SetTls warnings below). If -ffixed-r9 is unavailable or
// undesirable, leave STK_TLS_PREFER_REGISTER disabled; the kernel will fall back
// to a memory-based TLS slot with a small additional load/store per access.
#if STK_TLS && STK_TLS_PREFER_REGISTER

static __stk_forceinline Word GetTls()
{
    Word tp;
    __asm volatile("MOV %0, r9" : "=r"(tp) : /* input: none */ : /* clobbers: none */);
    return tp;
}

static __stk_forceinline void SetTls(Word tp)
{
    __asm volatile("MOV r9, %0" : /* output: none */ : "r"(tp) : /* clobbers: none */);
}
 
// Notify stk_arch.h that we defined inline versions of GetTls/SetTls.
#define STK_INLINE_TLS 1
 
#endif // STK_TLS_PREFER_REGISTER
 
} // namespace stk

static __stk_forceinline void __stk_dmb() { __asm volatile("dmb sy" ::: "memory"); }

#if defined(__ARM_FEATURE_CMSE) && (__ARM_FEATURE_CMSE == 3)
    #define STK_TZ_SECURE (1)
#else
    #define STK_TZ_SECURE (0)
#endif

#if defined(__ARM_FEATURE_CMSE) && (__ARM_FEATURE_CMSE == 1)
    #define STK_TZ_NON_SECURE (1)
#else
    #define STK_TZ_NON_SECURE (0)
#endif

#if defined(__ARM_FEATURE_CMSE) && (__ARM_FEATURE_CMSE == 3)
    #define __stk_tz_nsc_entry __attribute__((cmse_nonsecure_entry))
#else
    #define __stk_tz_nsc_entry
#endif

#if defined(__ARM_FEATURE_CMSE) && (__ARM_FEATURE_CMSE == 3)
    #define __stk_tz_ns_call __attribute__((cmse_nonsecure_call))
#else
    #define __stk_tz_ns_call
#endif

#define STK_TZ_NSC_GATEWAY extern "C" __stk_tz_nsc_entry
 
// ARM TrustZone Non-Secure binary configuration validation.
#ifdef _STK_CORTEX_M_TRUSTZONE_NON_SECURE
#if !STK_TZ_NON_SECURE
    #error "Switch of -cmse compiler flag for Non-Secure binary!"
#endif
#endif
 
#endif /* STK_ARCH_ARM_CORTEX_M_H_ */