Threads

Thread of execution. More...

Collaboration diagram for Threads:

Detailed Description

Thread of execution.

Data Structures
struct	thread_t
	Thread of execution structure. More...

Typedefs
typedef void(*	thread_kernel_entry_t) (void *arg)
	Kernel thread entry point function type.

Enumerations
enum	thread_state_t {   THREAD_PARKED = 0 , THREAD_ACTIVE , THREAD_PRE_BLOCK , THREAD_BLOCKED ,   THREAD_UNBLOCKING , THREAD_DYING }
	Thread state enum. More...

Functions
thread_t *	thread_new (process_t *process)
	Creates a new thread structure.
void	thread_free (thread_t *thread)
	Frees a thread structure.
tid_t	thread_kernel_create (thread_kernel_entry_t entry, void *arg)
	Creates a new thread that runs in kernel mode and submits it to the scheduler.
static thread_t *	thread_current (void)
	Retrieves the currently running thread.
static thread_t *	thread_current_unsafe (void)
	Retrieves the currently running thread without disabling interrupts.
static thread_t *	thread_idle (void)
	Retrieves the idle thread for the current CPU.
static thread_t *	thread_idle_unsafe (void)
	Retrieves the idle thread for the current CPU without disabling interrupts.
void	thread_save (thread_t *thread, const interrupt_frame_t *frame)
	Save state to a thread.
void	thread_load (thread_t *thread, interrupt_frame_t *frame)
	Load state from a thread.
bool	thread_is_note_pending (thread_t *thread)
	Check if a thread has a note pending.
uint64_t	thread_send_note (thread_t *thread, const char *string)
	Send a note to a thread.
uint64_t	thread_copy_from_user (thread_t *thread, void *dest, const void *userSrc, uint64_t length)
	Safely copy data from user space.
uint64_t	thread_copy_to_user (thread_t *thread, void *userDest, const void *src, uint64_t length)
	Safely copy data to user space.
uint64_t	thread_copy_from_user_terminated (thread_t *thread, const void *userArray, const void *terminator, uint8_t objectSize, uint64_t maxCount, void **outArray, uint64_t *outCount)
	Safely copy a null-terminated array of objects from user space.
uint64_t	thread_copy_from_user_string (thread_t *thread, char *dest, const char *userSrc, uint64_t size)
	Safely copy a string from user space.
uint64_t	thread_copy_from_user_pathname (thread_t *thread, pathname_t *pathname, const char *userPath)
	Safely copy a string from user space and use it to initialize a pathname.
uint64_t	thread_copy_from_user_string_array (thread_t *thread, const char **user, char ***out, uint64_t *outAmount)
	Safely copy a null-terminated array of strings and their contents from user space into a string vector.
uint64_t	thread_load_atomic_from_user (thread_t *thread, atomic_uint64_t *userObj, uint64_t *outValue)
	Atomically load a 64-bit value from a user-space atomic variable.
_NORETURN void	thread_jump (thread_t *thread)
	Jump to a thread by calling thread_load() and then loading its interrupt frame.

Typedef Documentation

thread_kernel_entry_t

typedef void(* thread_kernel_entry_t) (void *arg)

Kernel thread entry point function type.

Definition at line 110 of file thread.h.

Enumeration Type Documentation

thread_state_t

enum thread_state_t

Thread state enum.

Enumerator
THREAD_PARKED	Is doing nothing, not in a queue, not blocking, think of it as "other".
THREAD_ACTIVE	Is either running or ready to run.
THREAD_PRE_BLOCK	Has started the process of blocking but has not yet been given to a owner cpu.
THREAD_BLOCKED	Is blocking and waiting in one or multiple wait queues.
THREAD_UNBLOCKING	Has started unblocking, used to prevent the same thread being unblocked multiple times.
THREAD_DYING	The thread is currently dying, it will be freed by the scheduler once its invoked.

Definition at line 34 of file thread.h.

Function Documentation

thread_new()

thread_t * thread_new

(

process_t *

process

)

Creates a new thread structure.

Does not push the created thread to the scheduler or similar, merely handling allocation and initialization.

Parameters

process

The parent process that the thread will execute within.

Returns

On success, returns the newly created thread. On failure, returns NULL and errno is set.

Definition at line 50 of file thread.c.

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thread_free()

void thread_free

(

thread_t *

thread

)

Frees a thread structure.

Parameters

thread

The thread to be freed.

Definition at line 111 of file thread.c.

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thread_kernel_create()

tid_t thread_kernel_create	(	thread_kernel_entry_t	entry,
		void *	arg
	)

Creates a new thread that runs in kernel mode and submits it to the scheduler.

Parameters

entry	The entry point function for the thread.
arg	An argument to pass to the entry point function.

Returns

On success, returns the newly created thread ID. On failure, returns ERR and errno is set.

Definition at line 126 of file thread.c.

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thread_current()

static thread_t * thread_current ( void  )

inlinestatic

Retrieves the currently running thread.

Returns

The currently running thread.

Definition at line 126 of file thread.h.

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thread_current_unsafe()

static thread_t * thread_current_unsafe ( void  )

inlinestatic

Retrieves the currently running thread without disabling interrupts.

Returns

The currently running thread.

Definition at line 137 of file thread.h.

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thread_idle()

static thread_t * thread_idle ( void  )

inlinestatic

Retrieves the idle thread for the current CPU.

Returns

The idle thread for the current CPU.

Definition at line 147 of file thread.h.

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thread_idle_unsafe()

static thread_t * thread_idle_unsafe ( void  )

inlinestatic

Retrieves the idle thread for the current CPU without disabling interrupts.

Returns

The idle thread for the current CPU.

Definition at line 158 of file thread.h.

thread_save()

void thread_save	(	thread_t *	thread,
		const interrupt_frame_t *	frame
	)

Save state to a thread.

Parameters

thread	The destination thread where the state will be saved.
frame	The source frame..

Definition at line 153 of file thread.c.

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thread_load()

void thread_load	(	thread_t *	thread,
		interrupt_frame_t *	frame
	)

Load state from a thread.

Will retrieve the interrupt frame and setup the CPU with the threads contexts/data.

Parameters

thread	The source thread to load state from.
frame	The destination interrupt frame.

Definition at line 160 of file thread.c.

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thread_is_note_pending()

bool thread_is_note_pending

(

thread_t *

thread

)

Check if a thread has a note pending.

Parameters

thread

The thread to query.

Returns

True if there is a note pending, false otherwise.

Definition at line 171 of file thread.c.

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thread_send_note()

uint64_t thread_send_note	(	thread_t *	thread,
		const char *	string
	)

Send a note to a thread.

This function should always be used over the note_queue_push() function, as it performs additional checks, like unblocking the thread to notify it of the received note.

Parameters

thread	The destination thread.
string	The note string to send, should be a null-terminated string.

Returns

On success, 0. On failure, ERR and errno is set to:

• See note_send() for possible error codes.

Definition at line 176 of file thread.c.

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thread_copy_from_user()

uint64_t thread_copy_from_user	(	thread_t *	thread,
		void *	dest,
		const void *	userSrc,
		uint64_t	length
	)

Safely copy data from user space.

Will pin the user pages in memory while performing the copy and expand the user stack if necessary.

Parameters

thread	The thread performing the operation.
dest	The destination buffer in kernel space.
userSrc	The source buffer in user space.
length	The number of bytes to copy.

Returns

On success, 0. On failure, ERR and errno is set.

Definition at line 202 of file thread.c.

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thread_copy_to_user()

uint64_t thread_copy_to_user	(	thread_t *	thread,
		void *	userDest,
		const void *	src,
		uint64_t	length
	)

Safely copy data to user space.

Will pin the user pages in memory while performing the copy and expand the user stack if necessary.

Parameters

thread	The thread performing the operation.
userDest	The destination buffer in user space.
src	The source buffer in kernel space.
length	The number of bytes to copy.

Returns

On success, 0. On failure, ERR and errno is set.

Definition at line 220 of file thread.c.

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thread_copy_from_user_terminated()

uint64_t thread_copy_from_user_terminated	(	thread_t *	thread,
		const void *	userArray,
		const void *	terminator,
		uint8_t	objectSize,
		uint64_t	maxCount,
		void **	outArray,
		uint64_t *	outCount
	)

Safely copy a null-terminated array of objects from user space.

Parameters

thread	The thread performing the operation.
userArray	The source array in user space.
terminator	A pointer to the terminator object.
objectSize	The size of each object in the array.
maxCount	The maximum number of objects to copy.
outArray	Output pointer to store the allocated array in kernel space, must be freed by the caller.
outCount	Output pointer to store the number of objects copied, can be NULL.

Returns

On success, 0. On failure, ERR and errno is set.

Definition at line 238 of file thread.c.

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thread_copy_from_user_string()

uint64_t thread_copy_from_user_string	(	thread_t *	thread,
		char *	dest,
		const char *	userSrc,
		uint64_t	size
	)

Safely copy a string from user space.

Parameters

thread	The thread performing the operation.
dest	The destination buffer in kernel space.
userSrc	The source buffer in user space.
size	The size of the destination buffer.

Returns

On success, 0. On failure, ERR and errno is set.

Definition at line 278 of file thread.c.

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thread_copy_from_user_pathname()

uint64_t thread_copy_from_user_pathname	(	thread_t *	thread,
		pathname_t *	pathname,
		const char *	userPath
	)

Safely copy a string from user space and use it to initialize a pathname.

Parameters

thread	The thread performing the operation.
pathname	A pointer to the pathname to initialize.
userPath	The string in user space.

Returns

On success, 0. On failure, ERR and errno is set.

Definition at line 300 of file thread.c.

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thread_copy_from_user_string_array()

uint64_t thread_copy_from_user_string_array	(	thread_t *	thread,
		const char **	user,
		char ***	out,
		uint64_t *	outAmount
	)

Safely copy a null-terminated array of strings and their contents from user space into a string vector.

Parameters

thread	The thread performing the operation.
user	The source array of strings in user space.
out	Output pointer to store the allocated array of strings in kernel space, must be freed by the caller.
outAmount	Output pointer to store the number of strings copied, can be NULL.

Returns

On success, 0. On failure, ERR and errno is set.

Definition at line 328 of file thread.c.

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thread_load_atomic_from_user()

uint64_t thread_load_atomic_from_user	(	thread_t *	thread,
		atomic_uint64_t *	userObj,
		uint64_t *	outValue
	)

Atomically load a 64-bit value from a user-space atomic variable.

Will pin the user pages in memory while performing the load and expand the user stack if necessary.

Parameters

thread	The thread performing the operation.
userObj	The user-space atomic variable to load from.
outValue	Output pointer to store the loaded value.

Returns

On success, 0. On failure, ERR and errno is set.

Definition at line 373 of file thread.c.

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thread_jump()

_NORETURN void thread_jump ( thread_t *  thread )

extern

Jump to a thread by calling thread_load() and then loading its interrupt frame.

Must be done in assembly as it requires directly modifying registers.

Will never return instead it ends up at thread->frame.rip.

Parameters

thread

The thread to jump to.

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