API related to the message tag data type. More...

Collaboration diagram for Message Tag:

Data Structures
struct	l4_msgtag_t
	Message tag data structure. More...

Typedefs
typedef struct l4_msgtag_t	l4_msgtag_t
	Message tag data structure. More...

Enumerations
enum	L4_platform_ctl_proto { L4_PROTO_PLATFORM_CTL = 0 }
	Predefined protocol type for messages to platform-control objects. More...

enum	l4_msgtag_protocol { L4_PROTO_NONE = 0, L4_PROTO_ALLOW_SYSCALL = 1, L4_PROTO_PF_EXCEPTION = 1, L4_PROTO_IRQ = -1L, L4_PROTO_PAGE_FAULT = -2L, L4_PROTO_PREEMPTION = -3L, L4_PROTO_SYS_EXCEPTION = -4L, L4_PROTO_EXCEPTION = -5L, L4_PROTO_SIGMA0 = -6L, L4_PROTO_IO_PAGE_FAULT = -8L, L4_PROTO_KOBJECT = -10L, L4_PROTO_TASK = -11L, L4_PROTO_THREAD = -12L, L4_PROTO_LOG = -13L, L4_PROTO_SCHEDULER = -14L, L4_PROTO_FACTORY = -15L, L4_PROTO_VM = -16L, L4_PROTO_DMA_SPACE = -17L, L4_PROTO_IRQ_SENDER = -18L, L4_PROTO_IRQ_MUX = -19L, L4_PROTO_SEMAPHORE = -20L, L4_PROTO_META = -21L, L4_PROTO_IOMMU = -22L, L4_PROTO_DEBUGGER = -23L, L4_PROTO_SMCCC = -24L }
	Message tag for IPC operations. More...

enum	l4_msgtag_flags { L4_MSGTAG_ERROR, L4_MSGTAG_TRANSFER_FPU, L4_MSGTAG_SCHEDULE, L4_MSGTAG_PROPAGATE, L4_MSGTAG_FLAGS }
	Flags for message tags. More...

Functions
l4_msgtag_t	l4_msgtag (long label, unsigned words, unsigned items, unsigned flags) L4_NOTHROW
	Create a message tag from the specified values. More...

long	l4_msgtag_label (l4_msgtag_t t) L4_NOTHROW
	Get the protocol of tag. More...

unsigned	l4_msgtag_words (l4_msgtag_t t) L4_NOTHROW
	Get the number of untyped words. More...

unsigned	l4_msgtag_items (l4_msgtag_t t) L4_NOTHROW
	Get the number of typed items. More...

unsigned	l4_msgtag_flags (l4_msgtag_t t) L4_NOTHROW
	Get the flags. More...

unsigned	l4_msgtag_has_error (l4_msgtag_t t) L4_NOTHROW
	Test for error indicator flag. More...

unsigned	l4_msgtag_is_page_fault (l4_msgtag_t t) L4_NOTHROW
	Test for page-fault protocol. More...

unsigned	l4_msgtag_is_preemption (l4_msgtag_t t) L4_NOTHROW
	Test for preemption protocol. More...

unsigned	l4_msgtag_is_sys_exception (l4_msgtag_t t) L4_NOTHROW
	Test for system-exception protocol. More...

unsigned	l4_msgtag_is_exception (l4_msgtag_t t) L4_NOTHROW
	Test for exception protocol. More...

unsigned	l4_msgtag_is_sigma0 (l4_msgtag_t t) L4_NOTHROW
	Test for sigma0 protocol. More...

unsigned	l4_msgtag_is_io_page_fault (l4_msgtag_t t) L4_NOTHROW
	Test for IO-page-fault protocol. More...

Detailed Description

API related to the message tag data type.

Include File: #include <l4/sys/types.h>

Typedef Documentation

◆ l4_msgtag_t

typedef struct l4_msgtag_t l4_msgtag_t

Message tag data structure.

Include File: #include <l4/sys/types.h>

Describes the details of an IPC operation, in particular which parts of the UTCB have to be transmitted, and also flags to enable real-time and FPU extensions.

The message tag also contains a user-defined label that could be used to specify a protocol ID. Some negative values are reserved for kernel protocols such as page faults and exceptions.

The type must be treated completely opaque.

Enumeration Type Documentation

◆ l4_msgtag_flags

enum l4_msgtag_flags

Flags for message tags.

Enumerator
L4_MSGTAG_ERROR	Error indicator flag.
L4_MSGTAG_TRANSFER_FPU	Enable FPU transfer flag for IPC. By enabling this flag when sending IPC, the sender indicates that the contents of the FPU shall be transferred to the receiving thread. However, the receiver has to indicate its willingness to receive FPU context in its buffer descriptor register (BDR).
L4_MSGTAG_SCHEDULE	Enable schedule in IPC flag. Usually IPC operations donate the remaining time slice of a thread to the called thread. Enabling this flag when sending IPC does a real scheduling decision. However, this flag decreases IPC performance.
L4_MSGTAG_PROPAGATE	Enable IPC propagation. This flag enables IPC propagation, which means an IPC reply-connection from the current caller will be propagated to the new IPC receiver. This makes it possible to propagate an IPC call to a third thread, which may then directly answer to the caller.
L4_MSGTAG_FLAGS	Mask for all flags.

Definition at line 95 of file types.h.

◆ l4_msgtag_protocol

enum l4_msgtag_protocol

Message tag for IPC operations.

All predefined protocols used by the kernel.

Enumerator
L4_PROTO_NONE	Default protocol tag to reply to kernel.
L4_PROTO_ALLOW_SYSCALL	Allow an alien the system call.
L4_PROTO_PF_EXCEPTION	Make an exception out of a page fault.
L4_PROTO_IRQ	IRQ message.
L4_PROTO_PAGE_FAULT	Page fault message.
L4_PROTO_PREEMPTION	Preemption message.
L4_PROTO_SYS_EXCEPTION	System exception.
L4_PROTO_EXCEPTION	Exception.
L4_PROTO_SIGMA0	Sigma0 protocol.
L4_PROTO_IO_PAGE_FAULT	I/O page fault message.
L4_PROTO_KOBJECT	Protocol for messages to a generic kobject.
L4_PROTO_TASK	Protocol for messages to a task object.
L4_PROTO_THREAD	Protocol for messages to a thread object.
L4_PROTO_LOG	Protocol for messages to a log object.
L4_PROTO_SCHEDULER	Protocol for messages to a scheduler object.
L4_PROTO_FACTORY	Protocol for messages to a factory object.
L4_PROTO_VM	Protocol for messages to a virtual machine object.
L4_PROTO_DMA_SPACE	Protocol for (creating) kernel DMA space objects.
L4_PROTO_IRQ_SENDER	Protocol for IRQ senders (IRQ -> IPC)
L4_PROTO_IRQ_MUX	Protocol for IRQ mux (IRQ -> n x IRQ)
L4_PROTO_SEMAPHORE	Protocol for semaphore objects.
L4_PROTO_META	Meta information protocol.
L4_PROTO_IOMMU	Protocol ID for IO-MMUs.
L4_PROTO_DEBUGGER	Protocol ID for the debugger.
L4_PROTO_SMCCC	Protocol ID for ARM SMCCC calls.

Definition at line 49 of file types.h.

◆ L4_platform_ctl_proto

enum L4_platform_ctl_proto

Predefined protocol type for messages to platform-control objects.

Enumerator

L4_PROTO_PLATFORM_CTL

Protocol messages to a platform control object.

See L4_platform_ctl_ops for allowed operations.

Definition at line 147 of file platform_control.h.

Function Documentation

◆ l4_msgtag()

l4_msgtag_t l4_msgtag	(	long	label,
		unsigned	words,
		unsigned	items,
		unsigned	flags
	)

inline

Create a message tag from the specified values.

Message tag functions.

Parameters

label	The user-defined label
words	The number of untyped words within the UTCB
items	The number of typed items (e.g., flex pages) within the UTCB
flags	The IPC flags for realtime and FPU extensions

Returns: Message tag

Examples: examples/sys/aliens/main.c, examples/sys/ipc/ipc_example.c, examples/sys/singlestep/main.c, examples/sys/start-with-exc/main.c, and examples/sys/utcb-ipc/main.c.

Definition at line 408 of file types.h.

Referenced by L4::Irqep_t< Irq_object >::dispatch(), L4::Server< LOOP_HOOKS >::internal_loop(), l4_irq_trigger_u(), l4util_ioport_map(), L4::Thread::modify_senders(), and L4::Ipc_svr::Exc_dispatch< R, Exc >::operator()().

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◆ l4_msgtag_flags()

unsigned l4_msgtag_flags ( l4_msgtag_t t )

inline

Get the flags.

The flag are defined by l4_msgtag_flags.

Parameters

t The tag

Returns: Flags

Definition at line 432 of file types.h.

◆ l4_msgtag_has_error()

unsigned l4_msgtag_has_error ( l4_msgtag_t t )

inline

Test for error indicator flag.

Parameters

t The tag

Returns: >0 for yes, 0 for no

Return whether the kernel operation caused a communication error, e.g. with IPC. if true: utcb->error is valid, otherwise utcb->error is not valid

Examples: examples/sys/aliens/main.c, examples/sys/singlestep/main.c, and examples/sys/utcb-ipc/main.c.

Definition at line 437 of file types.h.

References L4_MSGTAG_ERROR.

Referenced by l4_ipc_error(), and l4_vcon_write_u().

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◆ l4_msgtag_is_exception()

unsigned l4_msgtag_is_exception ( l4_msgtag_t t )

inline

Test for exception protocol.

Parameters

t The tag

Returns: Boolean value

Examples: examples/sys/aliens/main.c, examples/sys/singlestep/main.c, and examples/sys/start-with-exc/main.c.

Definition at line 451 of file types.h.

References l4_msgtag_label(), and L4_PROTO_EXCEPTION.

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◆ l4_msgtag_is_io_page_fault()

unsigned l4_msgtag_is_io_page_fault ( l4_msgtag_t t )

inline

Test for IO-page-fault protocol.

Parameters

t The tag

Returns: Boolean value

Definition at line 457 of file types.h.

References l4_msgtag_label(), and L4_PROTO_IO_PAGE_FAULT.

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◆ l4_msgtag_is_page_fault()

unsigned l4_msgtag_is_page_fault ( l4_msgtag_t t )

inline

Test for page-fault protocol.

Parameters

t The tag

Returns: Boolean value

Definition at line 442 of file types.h.

References l4_msgtag_label(), and L4_PROTO_PAGE_FAULT.

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◆ l4_msgtag_is_preemption()

unsigned l4_msgtag_is_preemption ( l4_msgtag_t t )

inline

Test for preemption protocol.

Parameters

t The tag

Returns: Boolean value

Definition at line 445 of file types.h.

References l4_msgtag_label(), and L4_PROTO_PREEMPTION.

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◆ l4_msgtag_is_sigma0()

unsigned l4_msgtag_is_sigma0 ( l4_msgtag_t t )

inline

Test for sigma0 protocol.

Parameters

t The tag

Returns: Boolean value

Definition at line 454 of file types.h.

References l4_msgtag_label(), and L4_PROTO_SIGMA0.

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◆ l4_msgtag_is_sys_exception()

unsigned l4_msgtag_is_sys_exception ( l4_msgtag_t t )

inline

Test for system-exception protocol.

Parameters

t The tag

Returns: Boolean value

Definition at line 448 of file types.h.

References l4_msgtag_label(), and L4_PROTO_SYS_EXCEPTION.

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◆ l4_msgtag_items()

unsigned l4_msgtag_items ( l4_msgtag_t t )

inline

Get the number of typed items.

Parameters

t The tag

Returns: Number of items.

Definition at line 428 of file types.h.

Referenced by l4util_ioport_map().

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◆ l4_msgtag_label()

long l4_msgtag_label ( l4_msgtag_t t )

inline

Get the protocol of tag.

Parameters

t The tag

Returns: Label

Examples: examples/sys/singlestep/main.c, and examples/sys/start-with-exc/main.c.

Definition at line 420 of file types.h.

Referenced by l4_msgtag_is_exception(), l4_msgtag_is_io_page_fault(), l4_msgtag_is_page_fault(), l4_msgtag_is_preemption(), l4_msgtag_is_sigma0(), and l4_msgtag_is_sys_exception().

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◆ l4_msgtag_words()

unsigned l4_msgtag_words ( l4_msgtag_t t )

inline

Get the number of untyped words.

Parameters

t The tag

Returns: Number of words

Examples: examples/sys/utcb-ipc/main.c.

Definition at line 424 of file types.h.

Data Structures

Typedefs

Enumerations

Functions

Detailed Description

Typedef Documentation

◆ l4_msgtag_t

Enumeration Type Documentation

◆ l4_msgtag_flags

◆ l4_msgtag_protocol

◆ L4_platform_ctl_proto

Function Documentation

◆ l4_msgtag()

◆ l4_msgtag_flags()

◆ l4_msgtag_has_error()

◆ l4_msgtag_is_exception()

◆ l4_msgtag_is_io_page_fault()

◆ l4_msgtag_is_page_fault()

◆ l4_msgtag_is_preemption()

◆ l4_msgtag_is_sigma0()

◆ l4_msgtag_is_sys_exception()

◆ l4_msgtag_items()

◆ l4_msgtag_label()

◆ l4_msgtag_words()