mirror of
https://github.com/espressif/esp-idf.git
synced 2024-10-05 20:47:46 -04:00
fe0d4f2834
This commit refactors the pxPortInitialiseStack() function of the riscv
FreeRTOS ports (both IDF and SMP FreeRTOS).
- Each stack area is now separated into their own functions
- Each function will individually
- Push the stack pointer to allocate the stack area
- Initiaze the allocated stack area
- Each stack area's size and usage is now clearly documented in code
475 lines
18 KiB
C
475 lines
18 KiB
C
/*
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* SPDX-FileCopyrightText: 2020 Amazon.com, Inc. or its affiliates
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*
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* SPDX-License-Identifier: MIT
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*
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* SPDX-FileContributor: 2016-2022 Espressif Systems (Shanghai) CO LTD
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*/
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/*
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* FreeRTOS Kernel V10.4.3
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* Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy of
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* this software and associated documentation files (the "Software"), to deal in
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* the Software without restriction, including without limitation the rights to
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* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
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* the Software, and to permit persons to whom the Software is furnished to do so,
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* subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in all
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* copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
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* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
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* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
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* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*
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* https://www.FreeRTOS.org
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* https://github.com/FreeRTOS
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*
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* 1 tab == 4 spaces!
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*/
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/*-----------------------------------------------------------------------
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* Implementation of functions defined in portable.h for the RISC-V port.
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*----------------------------------------------------------------------*/
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#include "sdkconfig.h"
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#include <string.h>
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#include "soc/soc_caps.h"
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#include "soc/periph_defs.h"
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#include "soc/system_reg.h"
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#include "hal/systimer_hal.h"
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#include "hal/systimer_ll.h"
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#include "riscv/rvruntime-frames.h"
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#include "riscv/rv_utils.h"
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#include "riscv/interrupt.h"
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#include "esp_private/crosscore_int.h"
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#include "esp_attr.h"
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#include "esp_system.h"
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#include "esp_intr_alloc.h"
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#include "esp_log.h"
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#include "FreeRTOS.h" /* This pulls in portmacro.h */
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#include "task.h"
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#include "portmacro.h"
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#include "port_systick.h"
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#include "esp_memory_utils.h"
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/* ---------------------------------------------------- Variables ------------------------------------------------------
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*
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* ------------------------------------------------------------------------------------------------------------------ */
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static const char *TAG = "cpu_start"; // [refactor-todo]: might be appropriate to change in the future, but
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/**
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* @brief A variable is used to keep track of the critical section nesting.
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* @note This variable has to be stored as part of the task context and must be initialized to a non zero value
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* to ensure interrupts don't inadvertently become unmasked before the scheduler starts.
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* As it is stored as part of the task context it will automatically be set to 0 when the first task is started.
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*/
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static UBaseType_t uxCriticalNesting = 0;
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static UBaseType_t uxSavedInterruptState = 0;
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BaseType_t uxSchedulerRunning = 0;
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UBaseType_t uxInterruptNesting = 0;
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BaseType_t xPortSwitchFlag = 0;
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__attribute__((aligned(16))) static StackType_t xIsrStack[configISR_STACK_SIZE];
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StackType_t *xIsrStackTop = &xIsrStack[0] + (configISR_STACK_SIZE & (~((portPOINTER_SIZE_TYPE)portBYTE_ALIGNMENT_MASK)));
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/* ------------------------------------------------ FreeRTOS Portable --------------------------------------------------
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* - Provides implementation for functions required by FreeRTOS
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* - Declared in portable.h
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* ------------------------------------------------------------------------------------------------------------------ */
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// ----------------- Scheduler Start/End -------------------
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BaseType_t xPortStartScheduler(void)
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{
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uxInterruptNesting = 0;
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uxCriticalNesting = 0;
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uxSchedulerRunning = 0;
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/* Setup the hardware to generate the tick. */
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vPortSetupTimer();
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esprv_intc_int_set_threshold(1); /* set global INTC masking level */
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rv_utils_intr_global_enable();
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vPortYield();
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/*Should not get here*/
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return pdFALSE;
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}
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void vPortEndScheduler(void)
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{
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/* very unlikely this function will be called, so just trap here */
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abort();
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}
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// ------------------------ Stack --------------------------
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__attribute__((noreturn)) static void _prvTaskExitError(void)
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{
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/* A function that implements a task must not exit or attempt to return to
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its caller as there is nothing to return to. If a task wants to exit it
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should instead call vTaskDelete( NULL ).
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Artificially force an assert() to be triggered if configASSERT() is
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defined, then stop here so application writers can catch the error. */
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configASSERT(uxCriticalNesting == ~0UL);
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portDISABLE_INTERRUPTS();
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abort();
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}
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__attribute__((naked)) static void prvTaskExitError(void)
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{
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asm volatile(".option push\n" \
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".option norvc\n" \
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"nop\n" \
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".option pop");
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/* Task entry's RA will point here. Shifting RA into prvTaskExitError is necessary
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to make GDB backtrace ending inside that function.
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Otherwise backtrace will end in the function laying just before prvTaskExitError in address space. */
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_prvTaskExitError();
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}
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/**
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* @brief Align stack pointer in a downward growing stack
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*
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* This macro is used to round a stack pointer downwards to the nearest n-byte boundary, where n is a power of 2.
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* This macro is generally used when allocating aligned areas on a downward growing stack.
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*/
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#define STACKPTR_ALIGN_DOWN(n, ptr) ((ptr) & (~((n)-1)))
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/**
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* @brief Allocate and initialize GCC TLS area
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*
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* This function allocates and initializes the area on the stack used to store GCC TLS (Thread Local Storage) variables.
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* - The area's size is derived from the TLS section's linker variables, and rounded up to a multiple of 16 bytes
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* - The allocated area is aligned to a 16-byte aligned address
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* - The TLS variables in the area are then initialized
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*
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* Each task access the TLS variables using the THREADPTR register plus an offset to obtain the address of the variable.
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* The value for the THREADPTR register is also calculated by this function, and that value should be use to initialize
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* the THREADPTR register.
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*
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* @param[in] uxStackPointer Current stack pointer address
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* @param[out] ret_threadptr_reg_init Calculated THREADPTR register initialization value
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* @return Stack pointer that points to the TLS area
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*/
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FORCE_INLINE_ATTR UBaseType_t uxInitialiseStackTLS(UBaseType_t uxStackPointer, uint32_t *ret_threadptr_reg_init)
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{
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/*
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TLS layout at link-time, where 0xNNN is the offset that the linker calculates to a particular TLS variable.
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LOW ADDRESS
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|---------------------------| Linker Symbols
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| Section | --------------
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| .flash.rodata |
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0x0|---------------------------| <- _flash_rodata_start
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^ | Other Data |
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| |---------------------------| <- _thread_local_start
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| | .tbss | ^
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V | | |
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0xNNN | int example; | | tls_area_size
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| | |
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| .tdata | V
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|---------------------------| <- _thread_local_end
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| Other data |
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| ... |
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|---------------------------|
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HIGH ADDRESS
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*/
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// Calculate TLS area size and round up to multiple of 16 bytes.
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extern char _thread_local_start, _thread_local_end, _flash_rodata_start;
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const uint32_t tls_area_size = ALIGNUP(16, (uint32_t)&_thread_local_end - (uint32_t)&_thread_local_start);
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// TODO: check that TLS area fits the stack
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// Allocate space for the TLS area on the stack. The area must be aligned to 16-bytes
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uxStackPointer = STACKPTR_ALIGN_DOWN(16, uxStackPointer - (UBaseType_t)tls_area_size);
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// Initialize the TLS area with the initialization values of each TLS variable
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memcpy((void *)uxStackPointer, &_thread_local_start, tls_area_size);
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/*
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Calculate the THREADPTR register's initialization value based on the link-time offset and the TLS area allocated on
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the stack.
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HIGH ADDRESS
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|---------------------------|
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| .tdata (*) |
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^ | int example; |
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| | |
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| | .tbss (*) |
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| |---------------------------| <- uxStackPointer (start of TLS area)
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0xNNN | | | ^
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| | | |
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| ... | _thread_local_start - _rodata_start
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| | | |
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| | | V
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V | | <- threadptr register's value
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LOW ADDRESS
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*/
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*ret_threadptr_reg_init = (uint32_t)uxStackPointer - ((uint32_t)&_thread_local_start - (uint32_t)&_flash_rodata_start);
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return uxStackPointer;
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}
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/**
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* @brief Initialize the task's starting interrupt stack frame
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*
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* This function initializes the task's starting interrupt stack frame. The dispatcher will use this stack frame in a
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* context restore routine. Therefore, the starting stack frame must be initialized as if the task was interrupted right
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* before its first instruction is called.
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*
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* - The stack frame is allocated to a 16-byte aligned address
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*
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* @param[in] uxStackPointer Current stack pointer address
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* @param[in] pxCode Task function
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* @param[in] pvParameters Task function's parameter
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* @param[in] threadptr_reg_init THREADPTR register initialization value
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* @return Stack pointer that points to the stack frame
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*/
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FORCE_INLINE_ATTR UBaseType_t uxInitialiseStackFrame(UBaseType_t uxStackPointer, TaskFunction_t pxCode, void *pvParameters, uint32_t threadptr_reg_init)
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{
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/*
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Allocate space for the task's starting interrupt stack frame.
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- The stack frame must be allocated to a 16-byte aligned address.
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- We use XT_STK_FRMSZ (instead of sizeof(XtExcFrame)) as it rounds up the total size to a multiple of 16.
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*/
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uxStackPointer = STACKPTR_ALIGN_DOWN(16, uxStackPointer - RV_STK_FRMSZ);
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// Clear the entire interrupt stack frame
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RvExcFrame *frame = (RvExcFrame *)uxStackPointer;
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memset(frame, 0, sizeof(RvExcFrame));
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/*
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Initialize the stack frame.
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Note: Shifting RA into prvTaskExitError is necessary to make the GDB backtrace terminate inside that function.
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Otherwise, the backtrace will end in the function located just before prvTaskExitError in the address space.
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*/
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extern uint32_t __global_pointer$;
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frame->ra = (UBaseType_t)prvTaskExitError + 4; // size of the nop instruction at the beginning of prvTaskExitError
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frame->mepc = (UBaseType_t)pxCode;
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frame->a0 = (UBaseType_t)pvParameters;
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frame->gp = (UBaseType_t)&__global_pointer$;
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frame->tp = (UBaseType_t)threadptr_reg_init;
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return uxStackPointer;
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}
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StackType_t *pxPortInitialiseStack(StackType_t *pxTopOfStack, TaskFunction_t pxCode, void *pvParameters)
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{
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/*
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HIGH ADDRESS
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|---------------------------| <- pxTopOfStack on entry
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| TLS Variables |
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| ------------------------- | <- Start of useable stack
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| Starting stack frame |
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| ------------------------- | <- pxTopOfStack on return (which is the tasks current SP)
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| | |
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| V |
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----------------------------- <- Bottom of stack
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LOW ADDRESS
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- All stack areas are aligned to 16 byte boundary
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- We use UBaseType_t for all of stack area initialization functions for more convenient pointer arithmetic
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*/
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UBaseType_t uxStackPointer = (UBaseType_t)pxTopOfStack;
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// Initialize GCC TLS area
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uint32_t threadptr_reg_init;
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uxStackPointer = uxInitialiseStackTLS(uxStackPointer, &threadptr_reg_init);
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// Initialize the starting interrupt stack frame
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uxStackPointer = uxInitialiseStackFrame(uxStackPointer, pxCode, pvParameters, threadptr_reg_init);
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// Return the task's current stack pointer address which should point to the starting interrupt stack frame
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return (StackType_t *)uxStackPointer;
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//TODO: IDF-2393
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}
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/* ---------------------------------------------- Port Implementations -------------------------------------------------
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*
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* ------------------------------------------------------------------------------------------------------------------ */
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// --------------------- Interrupts ------------------------
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BaseType_t xPortInIsrContext(void)
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{
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return uxInterruptNesting;
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}
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BaseType_t IRAM_ATTR xPortInterruptedFromISRContext(void)
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{
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/* For single core, this can be the same as xPortInIsrContext() because reading it is atomic */
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return uxInterruptNesting;
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}
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// ---------------------- Spinlocks ------------------------
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// ------------------ Critical Sections --------------------
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void vPortEnterCritical(void)
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{
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BaseType_t state = portSET_INTERRUPT_MASK_FROM_ISR();
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uxCriticalNesting++;
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if (uxCriticalNesting == 1) {
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uxSavedInterruptState = state;
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}
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}
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void vPortExitCritical(void)
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{
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if (uxCriticalNesting > 0) {
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uxCriticalNesting--;
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if (uxCriticalNesting == 0) {
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portCLEAR_INTERRUPT_MASK_FROM_ISR(uxSavedInterruptState);
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}
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}
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}
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// ---------------------- Yielding -------------------------
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int vPortSetInterruptMask(void)
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{
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int ret;
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unsigned old_mstatus = RV_CLEAR_CSR(mstatus, MSTATUS_MIE);
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ret = REG_READ(INTERRUPT_CORE0_CPU_INT_THRESH_REG);
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REG_WRITE(INTERRUPT_CORE0_CPU_INT_THRESH_REG, RVHAL_EXCM_LEVEL);
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RV_SET_CSR(mstatus, old_mstatus & MSTATUS_MIE);
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/**
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* In theory, this function should not return immediately as there is a
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* delay between the moment we mask the interrupt threshold register and
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* the moment a potential lower-priority interrupt is triggered (as said
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* above), it should have a delay of 2 machine cycles/instructions.
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*
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* However, in practice, this function has an epilogue of one instruction,
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* thus the instruction masking the interrupt threshold register is
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* followed by two instructions: `ret` and `csrrs` (RV_SET_CSR).
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* That's why we don't need any additional nop instructions here.
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*/
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return ret;
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}
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void vPortClearInterruptMask(int mask)
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{
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REG_WRITE(INTERRUPT_CORE0_CPU_INT_THRESH_REG, mask);
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/**
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* The delay between the moment we unmask the interrupt threshold register
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* and the moment the potential requested interrupt is triggered is not
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* null: up to three machine cycles/instructions can be executed.
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*
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* When compilation size optimization is enabled, this function and its
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* callers returning void will have NO epilogue, thus the instruction
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* following these calls will be executed.
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*
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* If the requested interrupt is a context switch to a higher priority
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* task then the one currently running, we MUST NOT execute any instruction
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* before the interrupt effectively happens.
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* In order to prevent this, force this routine to have a 3-instruction
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* delay before exiting.
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*/
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asm volatile ( "nop" );
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asm volatile ( "nop" );
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asm volatile ( "nop" );
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}
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void vPortYield(void)
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{
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if (uxInterruptNesting) {
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vPortYieldFromISR();
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} else {
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esp_crosscore_int_send_yield(0);
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/* There are 3-4 instructions of latency between triggering the software
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interrupt and the CPU interrupt happening. Make sure it happened before
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we return, otherwise vTaskDelay() may return and execute 1-2
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instructions before the delay actually happens.
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(We could use the WFI instruction here, but there is a chance that
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the interrupt will happen while evaluating the other two conditions
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for an instant yield, and if that happens then the WFI would be
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waiting for the next interrupt to occur...)
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*/
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while (uxSchedulerRunning && uxCriticalNesting == 0 && REG_READ(SYSTEM_CPU_INTR_FROM_CPU_0_REG) != 0) {}
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}
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}
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void vPortYieldFromISR( void )
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{
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traceISR_EXIT_TO_SCHEDULER();
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uxSchedulerRunning = 1;
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xPortSwitchFlag = 1;
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}
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void vPortYieldOtherCore(BaseType_t coreid)
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{
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esp_crosscore_int_send_yield(coreid);
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}
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// ------------------- Hook Functions ----------------------
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void __attribute__((weak)) vApplicationStackOverflowHook(TaskHandle_t xTask, char *pcTaskName)
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{
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#define ERR_STR1 "***ERROR*** A stack overflow in task "
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#define ERR_STR2 " has been detected."
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const char *str[] = {ERR_STR1, pcTaskName, ERR_STR2};
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char buf[sizeof(ERR_STR1) + CONFIG_FREERTOS_MAX_TASK_NAME_LEN + sizeof(ERR_STR2) + 1 /* null char */] = {0};
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char *dest = buf;
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for (int i = 0; i < sizeof(str) / sizeof(str[0]); i++) {
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dest = strcat(dest, str[i]);
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}
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esp_system_abort(buf);
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}
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// ----------------------- System --------------------------
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uint32_t xPortGetTickRateHz(void)
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{
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return (uint32_t)configTICK_RATE_HZ;
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}
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#define STACK_WATCH_AREA_SIZE 32
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#define STACK_WATCH_POINT_NUMBER (SOC_CPU_WATCHPOINTS_NUM - 1)
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void vPortSetStackWatchpoint(void *pxStackStart)
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{
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uint32_t addr = (uint32_t)pxStackStart;
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addr = (addr + (STACK_WATCH_AREA_SIZE - 1)) & (~(STACK_WATCH_AREA_SIZE - 1));
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esp_cpu_set_watchpoint(STACK_WATCH_POINT_NUMBER, (char *)addr, STACK_WATCH_AREA_SIZE, ESP_CPU_WATCHPOINT_STORE);
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}
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/* ---------------------------------------------- Misc Implementations -------------------------------------------------
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*
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* ------------------------------------------------------------------------------------------------------------------ */
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// --------------------- App Start-up ----------------------
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/* [refactor-todo]: See if we can include this through a header */
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extern void esp_startup_start_app_common(void);
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void esp_startup_start_app(void)
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{
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esp_startup_start_app_common();
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ESP_LOGI(TAG, "Starting scheduler.");
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vTaskStartScheduler();
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}
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