Scheduler implementation

Kernel scheduler internals. More...

Macros
#define	STATIC   static

Functions
uint32_t *	os_thread_populate_stack (int stack_id, unsigned stack_size, entrypoint_t *entrypoint, void *data)
	Populate stack of new thread so it can be executed.
int	os_process_create (Process_t process_id, const struct OS_process_definition_t *definition)
	Create process using process definition.
void	os_boot_thread (Thread_t boot_thread)
	Start executing thread.
void	os_reset_cpu ()
	Reset the CPU.
void	cmrx_shutdown_handler (void)
	Default CMRX shutdown handler for ARM CPUs This is default action after for when the CMRX kernel is shutdown.
void	os_kernel_shutdown ()
	Perform the kernel shutdown.
int	os_set_syscall_return_value (Thread_t thread_id, int32_t retval)
	Set return value of syscall for given thread.

Detailed Description

Kernel scheduler internals.

Macro Definition Documentation

STATIC

#define STATIC   static

Function Documentation

cmrx_shutdown_handler()

void cmrx_shutdown_handler

(

void

)

Default CMRX shutdown handler for ARM CPUs This is default action after for when the CMRX kernel is shutdown.

It will reset the CPU. If you want to perform different action, then provide your function called `cmrx_shutdown_handler. It will override this one.

Note

Your function should not return nor try to restart CMRX kernel. If you want to restart the kernel, then perform CPU reset first.

os_boot_thread()

void os_boot_thread

(

Thread_t

boot_thread

)

Start executing thread.

Used to actually start executing in thread mode just after the kernel has been initialized and is ready to start the first thread. This function has to perform CPU switch from privileged mode in which kernel runs into unprivileged mode in which threads are supposed to run. Thread passed to this function is in state ready to be executed by normal kernel thread switching mechanism on this platform.

Parameters

boot_thread

ID of thread that shall be started

os_kernel_shutdown()

void os_kernel_shutdown

(

)

Perform the kernel shutdown.

Stop running the kernel.

This is platform-specific way of how to shutdown the kernel. In this case an interrupt frame is forged on stack that will resemble a frame returning back to the cmrx_shutdown_handler function. The result of running this function will be that the processor leaves the handler mode, enters privileged thread mode and will be using MSP.

os_process_create()

int os_process_create	(	Process_t	process_id,
		const struct OS_process_definition_t *	definition
	)

Create process using process definition.

Takes process definition and initializes MPU regions for process out of it.

Parameters

process_id	ID of process to be initialized
definition	process definition. This is constructed at compile time using OS_APPLICATION macros

Returns

E_OK if process was contructed properly, E_INVALID if process ID is already used or if process definition contains invalid section boundaries. E_OUT_OF_RANGE is returned if process ID requested is out of limits given by the size of process table.

os_reset_cpu()

void os_reset_cpu

(

)

Reset the CPU.

This is architecture- (and possibly HAL-) specific way to reset the CPU. This function can be used before the kernel has been started or after it has been shut down. If there is no shutdown handler provided by the integrator then the default handler will call this function to reset the CPU automatically.

os_set_syscall_return_value()

int os_set_syscall_return_value	(	Thread_t	thread_id,
		int32_t	retval
	)

Set return value of syscall for given thread.

Parameters

thread_id	Id of the thread whose exception handler is being modified
retval	value to store on the stack

os_thread_populate_stack()

uint32_t * os_thread_populate_stack	(	int	stack_id,
		unsigned	stack_size,
		entrypoint_t *	entrypoint,
		void *	data
	)

Populate stack of new thread so it can be executed.

Populates stack of new thread so that it can be executed with no other actions required. Returns the address where SP shall point to.

Parameters

stack_id	ID of stack to be populated
stack_size	size of stack in 32-bit quantities
entrypoint	address of thread entrypoint function
data	address of data passed to the thread as its 1st argument

Returns

Address to which the SP shall be set.