Locking services

The Xenomai core deals with concurrent activities from two distinct kernels running side-by-side. More...

Collaboration diagram for Locking services:

Macros
#define	splhigh(x)   ((x) = ipipe_test_and_stall_head() & 1)
	Hard disable interrupts on the local processor, saving previous state. More...
#define	splexit(x)   ipipe_restore_head(x & 1)
	Restore the saved hard interrupt state on the local processor. More...
#define	splmax()   ipipe_stall_head()
	Hard disable interrupts on the local processor.
#define	splnone()   ipipe_unstall_head()
	Hard enable interrupts on the local processor.
#define	spltest()   ipipe_test_head()
	Test hard interrupt state on the local processor. More...

Detailed Description

The Xenomai core deals with concurrent activities from two distinct kernels running side-by-side.

When interrupts are involved, the services from this section control the hard interrupt state exclusively, for protecting against processor-local or SMP concurrency.

Note

In a dual kernel configuration, hard interrupts are gated by the CPU. When enabled, hard interrupts are immediately delivered to the Xenomai core if they belong to a real-time source, or deferred until enabled by a second-stage virtual interrupt mask, if they belong to regular Linux devices/sources.

Macro Definition Documentation

splexit

#define splexit

(

x

)

ipipe_restore_head(x & 1)

Restore the saved hard interrupt state on the local processor.

Parameters

[in]

x

The context variable previously updated by splhigh()

splhigh

#define splhigh

(

x

)

((x) = ipipe_test_and_stall_head() & 1)

Hard disable interrupts on the local processor, saving previous state.

Parameters

[out]

x

An unsigned long integer context variable

spltest

#define spltest

(

)

ipipe_test_head()

Test hard interrupt state on the local processor.

Returns

Zero if the local processor currently accepts interrupts, non-zero otherwise.

Referenced by rtdm_fd_select(), and rtdm_lock_get().