Capabilities

C interface for capabilities. More...

Collaboration diagram for Capabilities:

Typedefs
typedef unsigned long	l4_cap_idx_t
	Capability selector type.

Enumerations
enum	l4_cap_consts_t {   L4_CAP_SHIFT , L4_CAP_SIZE = 1UL << L4_CAP_SHIFT , L4_CAP_OFFSET , L4_CAP_MASK ,   L4_INVALID_CAP , L4_INVALID_CAP_BIT = 1UL << (L4_CAP_SHIFT - 1) }
	Constants related to capability selectors. More...
enum	l4_default_caps_t {   L4_BASE_TASK_CAP , L4_BASE_FACTORY_CAP , L4_BASE_THREAD_CAP , L4_BASE_PAGER_CAP ,   L4_BASE_LOG_CAP , L4_BASE_ICU_CAP , L4_BASE_SCHEDULER_CAP , L4_BASE_IOMMU_CAP ,   L4_BASE_DEBUGGER_CAP , L4_BASE_ARM_SMCCC_CAP , L4_BASE_CAPS_LAST_P1 , L4_BASE_CAPS_LAST = L4_BASE_CAPS_LAST_P1 - 1 }
	Default capabilities setup for the initial tasks. More...

Functions
unsigned	l4_is_invalid_cap (l4_cap_idx_t c) L4_NOTHROW
	Test if a capability selector is the invalid capability.
unsigned	l4_is_valid_cap (l4_cap_idx_t c) L4_NOTHROW
	Test if a capability selector is a valid selector.
unsigned	l4_capability_equal (l4_cap_idx_t c1, l4_cap_idx_t c2) L4_NOTHROW
	Test if the capability indices of two capability selectors are equal.

Detailed Description

C interface for capabilities.

Add

#include <l4/sys/types.h>
#include <l4/sys/consts.h>

to your code to use the functions and definitions explained here.

Typedef Documentation

l4_cap_idx_t

typedef unsigned long l4_cap_idx_t

Capability selector type.

A capability selector is either a (shifted) capability index or the invalid capability selector L4_INVALID_CAP.

Usage of the invalid capability selector is defined only for invoking IPC (see Object Invocation): When IPC is invoked on L4_INVALID_CAP, then it is resolved to a capability for the current thread with full permissions.

Otherwise, the API assumes that each argument of type l4_cap_idx_t is a capability index, i.e., idx << L4_CAP_SHIFT for arbitrary idx. The behavior for other arguments is then undefined.

Examples

examples/libs/shmc/prodcons.c, examples/sys/aliens/main.c, examples/sys/isr/main.c, examples/sys/singlestep/main.c, examples/sys/start-with-exc/main.c, and examples/sys/utcb-ipc/main.c.

Definition at line 336 of file types.h.

Enumeration Type Documentation

l4_cap_consts_t

enum l4_cap_consts_t

Constants related to capability selectors.

Enumerator
L4_CAP_SHIFT	Capability index shift.
L4_CAP_SIZE	Deprecated Superseded by L4_CAP_OFFSET.
L4_CAP_OFFSET	Offset of two consecutive capability selectors.
L4_CAP_MASK	Mask to get only the relevant bits of an l4_cap_idx_t.
L4_INVALID_CAP	Invalid capability selector.

Definition at line 139 of file consts.h.

l4_default_caps_t

enum l4_default_caps_t

Default capabilities setup for the initial tasks.

These capability selectors are setup per default by the micro kernel for the two initial tasks, the Root-Pager (Sigma0) and the Root-Task (Moe).

Attention

These constants do not have any particular meaning for applications started by Moe, see Initial Environment for this kind of information.

See also

Initial Environment for information useful for normal user applications.

Enumerator
L4_BASE_TASK_CAP	Capability selector for the current task.
L4_BASE_FACTORY_CAP	Capability selector for the factory.
L4_BASE_THREAD_CAP	Capability selector for the first thread.
L4_BASE_PAGER_CAP	Capability selector for the pager gate. For Sigma0, the pager is not present since it never raises page faults. For Moe, the pager is set to Sigma0.
L4_BASE_LOG_CAP	Capability selector for the log object. Present if the corresponding feature is turned on in the microkernel configuration.
L4_BASE_ICU_CAP	Capability selector for the base icu object.
L4_BASE_SCHEDULER_CAP	Capability selector for the scheduler cap.
L4_BASE_IOMMU_CAP	Capability selector for the IO-MMU cap. Present if the microkernel detected an IO-MMU.
L4_BASE_DEBUGGER_CAP	Capability selector for the debugger cap. Present if the corresponding feature is turned on in the microkernel configuration.
L4_BASE_ARM_SMCCC_CAP	Capability selector for the ARM SMCCC cap. Present if the microkernel detected an ARM SMC capable trusted execution environment.
L4_BASE_CAPS_LAST	Last capability index used for base capabilities.

Definition at line 324 of file consts.h.

Function Documentation

l4_capability_equal()

unsigned l4_capability_equal ( l4_cap_idx_t c1, l4_cap_idx_t c2 )

inline

Test if the capability indices of two capability selectors are equal.

Parameters

c1	Capability selector.
c2	Capability selector.

Return values

0	The index parts of the capability selectors differ.
1	The index parts of the capability selectors are equal.

Precondition

Both capability selectors must be valid (cf. l4_is_valid_cap()) otherwise the return value is undefined.

Definition at line 397 of file types.h.

References L4_CAP_SHIFT, and L4_NOTHROW.

l4_is_invalid_cap()

unsigned l4_is_invalid_cap ( l4_cap_idx_t c )

inline

Test if a capability selector is the invalid capability.

Parameters

c	Capability selector

Return values

0	The capability selector is not the invalid capability.
>0	The capability selector is the invalid capability.

Examples

examples/libs/l4re/c/ma+rm.c, examples/sys/aliens/main.c, examples/sys/isr/main.c, examples/sys/singlestep/main.c, examples/sys/start-with-exc/main.c, and examples/sys/utcb-ipc/main.c.

Definition at line 389 of file types.h.

References L4_NOTHROW.

l4_is_valid_cap()

unsigned l4_is_valid_cap ( l4_cap_idx_t c )

inline

Test if a capability selector is a valid selector.

Parameters

c	Capability selector

Return values

0	The capability selector is not valid.
>0	The capability selector is valid.

Definition at line 393 of file types.h.

References L4_NOTHROW.

Referenced by L4Re::Util::Cap_alloc_base::free(), and L4Re::Util::Counting_cap_alloc< COUNTERTYPE, Dbg >::free().

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