ICARUS Kernel Core - State and Initialization. More...

#include <stdint.h>
#include <stdbool.h>
#include "bsp/retarget_hal.h"
#include "icarus/config.h"
#include "icarus/types.h"

Functions
void	os_init (void)
	Initialize the ICARUS kernel.

void	os_start (void)
	Start the ICARUS scheduler.

void	os_yield (void)
	Voluntarily yield CPU to scheduler.

uint32_t	task_active_sleep (uint32_t ticks)
	Sleep for specified ticks (cooperative, via SVC)

const char *	os_get_current_task_name (void)
	Get name of currently executing task.

void	enter_critical (void)
	Enter critical section (disable scheduler)

void	exit_critical (void)
	Exit critical section (re-enable scheduler if outermost)

uint32_t *	kernel_get_stack (uint8_t task_idx)
	Get stack pointer for task index (internal use)

uint32_t *	kernel_get_data (uint8_t task_idx)
	Get data pointer for task index (internal use)

void *	kernel_protected_data (uint16_t num_words)
	Allocate protected data words for current task.

bool	bkpram_write (const void *src, uint32_t offset, uint32_t len)
	Copy data into battery-backed RAM (RAM_D3) via SVC.

void	__enter_critical (void)
	Privileged implementation of enter_critical.

void	__exit_critical (void)
	Privileged implementation of exit_critical.

void	__os_init (void)
	Privileged implementation of os_init.

void	__os_start (void)
	Privileged implementation of os_start.

void *	__kernel_protected_data (uint16_t num_words)
	Privileged implementation of kernel_protected_data.

uint32_t *	__kernel_get_stack (uint8_t task_idx)
	Privileged implementation of kernel_get_stack.

uint32_t *	__kernel_get_data (uint8_t task_idx)
	Privileged implementation of kernel_get_data.

Variables
icarus_task_t *	task_list [128]
	Array of pointers to all task control blocks.

icarus_semaphore_t *	semaphore_list [64]
	Array of pointers to all semaphores.

icarus_pipe_t *	message_pipe_list [64]
	Array of pointers to all message pipes.

uint8_t	current_task_index
	Index of currently executing task.

uint8_t	running_task_count
	Count of tasks in active states.

uint8_t	num_created_tasks
	Total number of created tasks.

volatile uint32_t	current_task_ticks_remaining
	Ticks remaining in current task's time slice.

volatile uint32_t	ticks_per_task
	Configured ticks per time slice.

volatile uint32_t	os_tick_count
	System tick counter.

volatile uint8_t	os_running
	Flag indicating OS is running.

volatile bool	scheduler_enabled
	Scheduler enable flag.

int8_t	cleanup_task_idx [128]
	Cleanup task index queue.

int8_t	current_cleanup_task_idx
	Current cleanup queue write index.

Detailed Description

ICARUS Kernel Core - State and Initialization.

Version: 0.1.0

Core kernel state variables, data structures, and initialization. This is the foundation layer that other kernel modules depend on.

Author: Souham Biswas

Date: 2025

Copyright: Copyright 2025-2026 Souham Biswas https://github.com/ironhide23586/icarus-os-core Licensed under the Apache License, Version 2.0

Definition in file kernel.h.

Function Documentation

◆ __enter_critical()

void __enter_critical ( void )

Privileged implementation of enter_critical.

Note: Internal function - use enter_critical() wrapper

Definition at line 114 of file kernel.c.

References critical_stack_depth, and scheduler_enabled.

Referenced by crc16_ccitt(), enter_critical(), and SVC_Handler_C().

◆ __exit_critical()

void __exit_critical ( void )

Privileged implementation of exit_critical.

Note: Internal function - use exit_critical() wrapper

Definition at line 124 of file kernel.c.

References critical_stack_depth, and scheduler_enabled.

Referenced by crc16_ccitt(), exit_critical(), and SVC_Handler_C().

◆ __kernel_get_data()

uint32_t * __kernel_get_data ( uint8_t task_idx )

Privileged implementation of kernel_get_data.

Note: Internal function - use kernel_get_data() wrapper

Definition at line 282 of file kernel.c.

References data_pool.

Referenced by __os_register_task(), kernel_get_data(), and SVC_Handler_C().

◆ __kernel_get_stack()

uint32_t * __kernel_get_stack ( uint8_t task_idx )

Privileged implementation of kernel_get_stack.

Note: Internal function - use kernel_get_stack() wrapper

Definition at line 269 of file kernel.c.

References stack_pool.

Referenced by __os_register_task(), kernel_get_stack(), and SVC_Handler_C().

◆ __kernel_protected_data()

void * __kernel_protected_data ( uint16_t num_words )

Privileged implementation of kernel_protected_data.

Note: Internal function - use kernel_protected_data() wrapper; Runs in SVC handler — already atomic, no critical section needed

Definition at line 295 of file kernel.c.

References current_task_index, data_pool, data_pool_word_offsets, and ICARUS_DATA_WORDS.

Referenced by kernel_protected_data(), and SVC_Handler_C().

◆ __os_init()

void __os_init ( void )

Privileged implementation of os_init.

Note: Internal function - use os_init() wrapper

Definition at line 212 of file kernel.c.

References __init_pipe(), __init_sem(), __os_register_task(), cleanup_task_idx, cpu_vregisters, current_cleanup_task_idx, current_task_index, current_task_ticks_remaining, data_pool_word_offsets, ICARUS_MAX_MESSAGE_QUEUES, ICARUS_MAX_SEMAPHORES, ICARUS_MAX_TASKS, ICARUS_TICKS_PER_TASK, message_pipe_list, message_pipe_pool, os_idle_task(), os_running, running_task_count, scheduler_enabled, semaphore_list, semaphore_pool, task_list, task_pool, and ticks_per_task.

Referenced by os_init().

◆ __os_start()

void __os_start ( void )

Privileged implementation of os_start.

Note: Internal function - use os_start() wrapper

Definition at line 253 of file kernel.c.

References current_task_index, ICARUS_MAX_TASKS, num_created_tasks, start_cold_task(), and task_list.

Referenced by os_start().

◆ bkpram_write()

bool bkpram_write	(	const void *	src,
		uint32_t	offset,
		uint32_t	len
	)

Copy data into battery-backed RAM (RAM_D3) via SVC.

On target this issues an SVC that runs a validated memcpy in privileged mode, allowing unprivileged tasks to persist data into BKPRAM without an MPU region grant. Under HOST_TEST the call is a no-op that returns true.

Parameters

[in]	src	Source buffer (caller-owned, any memory domain).
[in]	offset	Byte offset into BKPRAM (0 .. BSP_RAM_D3_SIZE-1).
[in]	len	Number of bytes to copy (must be > 0).

Return values

true	Write completed successfully.
false	Validation failed (offset+len exceeds BKPRAM, or len==0).

Copy data into battery-backed RAM (RAM_D3) via SVC.

On target this issues an SVC that runs a validated memcpy in privileged mode, allowing unprivileged tasks to persist data into BKPRAM without an MPU region grant. Under HOST_TEST the call is a no-op that returns true.

Parameters

[in]	src	Source buffer (caller-owned, any memory domain).
[in]	offset	Byte offset into BKPRAM (0 .. BSP_RAM_D3_SIZE-1).
[in]	len	Number of bytes to copy (must be > 0).

Return values

true	Write completed successfully.
false	Validation failed (offset+len exceeds BKPRAM, or len==0).

Copy data into battery-backed RAM (RAM_D3) via SVC.

Definition at line 1737 of file svc.c.

References SVC_BKPRAM_WRITE.

◆ enter_critical()

void enter_critical ( void )

Enter critical section (disable scheduler)

Note: Supports nesting

Definition at line 478 of file svc.c.

References __enter_critical(), and SVC_ENTER_CRITICAL.

Referenced by __task_blocking_sleep().

◆ exit_critical()

void exit_critical ( void )

Exit critical section (re-enable scheduler if outermost)

Definition at line 489 of file svc.c.

References __exit_critical(), and SVC_EXIT_CRITICAL.

Referenced by __task_blocking_sleep().

◆ kernel_get_data()

uint32_t * kernel_get_data ( uint8_t task_idx )

Get data pointer for task index (internal use)

Parameters

task_idx Task index

Returns: Pointer to data memory

Get data pointer for task index (internal use)

Definition at line 734 of file svc.c.

References __kernel_get_data(), and SVC_KERNEL_GET_DATA.

◆ kernel_get_stack()

uint32_t * kernel_get_stack ( uint8_t task_idx )

Get stack pointer for task index (internal use)

Parameters

task_idx Task index

Returns: Pointer to stack memory

Get stack pointer for task index (internal use)

Definition at line 714 of file svc.c.

References __kernel_get_stack(), and SVC_KERNEL_GET_STACK.

◆ kernel_protected_data()

void * kernel_protected_data ( uint16_t num_words )

Allocate protected data words for current task.

Definition at line 754 of file svc.c.

References __kernel_protected_data(), and SVC_KERNEL_PROTECTED_DATA.

◆ os_get_current_task_name()

const char * os_get_current_task_name ( void )

Get name of currently executing task.

Definition at line 575 of file svc.c.

References __os_get_current_task_name(), and SVC_OS_GET_CURRENT_TASK_NAME.

Referenced by os_heartbeat_task().

◆ os_init()

void os_init ( void )

Initialize the ICARUS kernel.

Must be called before any other kernel function. Initializes:

Task pool and task list
Semaphore pool
Message pipe pool
System tasks (idle, heartbeat)

Precondition: HAL must be initialized (hal_init() called)

Postcondition: Kernel is ready for task registration

Definition at line 501 of file svc.c.

References __os_init().

Referenced by main().

◆ os_start()

void os_start ( void )

Start the ICARUS scheduler.

Begins task execution. This function does not return.

Precondition: os_init() must have been called; At least one task must be registered

Warning: This function never returns!

Definition at line 502 of file svc.c.

References __os_start().

Referenced by main().

◆ os_yield()

void os_yield ( void )

Voluntarily yield CPU to scheduler.

Definition at line 511 of file svc.c.

References __os_yield(), and SVC_OS_YIELD.

Referenced by os_idle_task().

◆ task_active_sleep()

uint32_t task_active_sleep ( uint32_t ticks )

Sleep for specified ticks (cooperative, via SVC)

Definition at line 522 of file svc.c.

References __task_active_sleep(), and SVC_TASK_ACTIVE_SLEEP.

Referenced by __pipe_dequeue(), __pipe_enqueue(), __semaphore_consume(), __semaphore_consume_timeout(), __semaphore_feed(), CDC_Write(), and os_heartbeat_task().

Variable Documentation

◆ cleanup_task_idx

int8_t cleanup_task_idx[128]

extern

Cleanup task index queue.

Definition at line 57 of file kernel.c.

Referenced by __os_exit_task(), __os_init(), and __os_kill_process().

◆ current_cleanup_task_idx

int8_t current_cleanup_task_idx

extern

Current cleanup queue write index.

Definition at line 73 of file kernel.c.

Referenced by __os_exit_task(), __os_init(), and __os_kill_process().

◆ current_task_index

uint8_t current_task_index

extern

Index of currently executing task.

Definition at line 63 of file kernel.c.

Referenced by __kernel_protected_data(), __os_exit_task(), __os_get_current_task_name(), __os_init(), __os_kill_process(), __os_start(), __os_task_suicide(), and __task_active_sleep().

◆ current_task_ticks_remaining

volatile uint32_t current_task_ticks_remaining

extern

Ticks remaining in current task's time slice.

Definition at line 66 of file kernel.c.

Referenced by __os_get_task_ticks_remaining(), __os_init(), __os_yield(), and SysTick_Handler().

◆ message_pipe_list

icarus_pipe_t* message_pipe_list[64]

extern

Array of pointers to all message pipes.

Definition at line 52 of file kernel.c.

Referenced by __init_pipe(), __os_init(), __pipe_can_dequeue(), __pipe_can_enqueue(), __pipe_dequeue(), __pipe_enqueue(), __pipe_get_count(), __pipe_get_max_count(), __pipe_init(), __pipe_read_bytes(), and __pipe_write_bytes().

◆ num_created_tasks

uint8_t num_created_tasks

extern

Total number of created tasks.

Definition at line 65 of file kernel.c.

Referenced by __os_get_current_task_name(), __os_get_num_created_tasks(), __os_get_stack_watermark(), __os_get_task_dispatch_count(), __os_get_task_name(), __os_get_task_state(), __os_kill_process(), __os_register_task(), __os_restart_task(), __os_start(), __os_update_stack_watermark(), and os_create_task().

◆ os_running

volatile uint8_t os_running

extern

Flag indicating OS is running.

Definition at line 70 of file kernel.c.

Referenced by __os_init(), __os_is_running(), and SysTick_Handler().

◆ os_tick_count

volatile uint32_t os_tick_count

extern

System tick counter.

Definition at line 69 of file kernel.c.

Referenced by __init_pipe(), __init_sem(), __os_get_tick_count(), __pipe_init(), __pipe_read_bytes(), __pipe_write_bytes(), __sem_decrement(), __sem_increment(), __semaphore_init(), __task_active_sleep(), __task_busy_wait(), and SysTick_Handler().

◆ running_task_count

uint8_t running_task_count

extern

Count of tasks in active states.

Definition at line 64 of file kernel.c.

Referenced by __os_exit_task(), __os_get_running_task_count(), __os_init(), __os_kill_process(), __os_restart_task(), and os_create_task().

◆ scheduler_enabled

volatile bool scheduler_enabled

extern

Scheduler enable flag.

Definition at line 72 of file kernel.c.

Referenced by __enter_critical(), __exit_critical(), __os_init(), and SysTick_Handler().

◆ semaphore_list

icarus_semaphore_t* semaphore_list[64]

extern

Array of pointers to all semaphores.

Definition at line 51 of file kernel.c.

Referenced by __init_sem(), __os_init(), __sem_can_consume(), __sem_can_feed(), __sem_decrement(), __sem_increment(), __semaphore_consume(), __semaphore_consume_timeout(), __semaphore_feed(), __semaphore_get_count(), __semaphore_get_max_count(), and __semaphore_init().

◆ task_list

icarus_task_t* task_list[128]

extern

Array of pointers to all task control blocks.

Definition at line 50 of file kernel.c.

Referenced by __os_exit_task(), __os_get_current_task_name(), __os_get_stack_watermark(), __os_get_task_dispatch_count(), __os_get_task_name(), __os_get_task_state(), __os_init(), __os_kill_process(), __os_register_task(), __os_restart_task(), __os_start(), __os_task_suicide(), __os_update_stack_watermark(), and __task_active_sleep().

◆ ticks_per_task

volatile uint32_t ticks_per_task

extern

Configured ticks per time slice.

Definition at line 67 of file kernel.c.

Referenced by __os_init(), and __os_yield().

Functions

Variables

Detailed Description

Function Documentation

◆ __enter_critical()

◆ __exit_critical()

◆ __kernel_get_data()

◆ __kernel_get_stack()

◆ __kernel_protected_data()

◆ __os_init()

◆ __os_start()

◆ bkpram_write()

◆ enter_critical()

◆ exit_critical()

◆ kernel_get_data()

◆ kernel_get_stack()

◆ kernel_protected_data()

◆ os_get_current_task_name()

◆ os_init()

◆ os_start()

◆ os_yield()

◆ task_active_sleep()

Variable Documentation

◆ cleanup_task_idx

◆ current_cleanup_task_idx

◆ current_task_index

◆ current_task_ticks_remaining

◆ message_pipe_list

◆ num_created_tasks

◆ os_running

◆ os_tick_count

◆ running_task_count

◆ scheduler_enabled

◆ semaphore_list

◆ task_list

◆ ticks_per_task