splraise(9) - NetBSD Manual Pages

SPLRAISE(9)            NetBSD Kernel Developer's Manual            SPLRAISE(9)


NAME

     spllower, splraise -- modify system interrupt priority level


SYNOPSIS

     #include <machine/intr.h>

     void
     spllower(int s);

     int
     splraise(int s);


DESCRIPTION

     These functions raise and lower the interrupt priority level on i386.
     They are used by machine-dependent kernel code to implement the machine-
     independent spl(9) interface.

     In a multi-CPU system, these functions change the interrupt priority
     level on the local CPU only.  In general, device drivers should not make
     use of these functions.

     The spllower() function sets the system priority level to the one encoded
     in s, if s is lower than the current level.  Otherwise, it does not
     change the level.  Use splx() instead of spllower(), except in extraordi-
     nary circumstances.

     The splraise() function sets the system priority level to the one encoded
     in s, if s is greater than the current level, and returns the previous
     level.  Otherwise, it does not change the level, and it returns the cur-
     rent level.  Except in extraordinary circumstances, do not use
     splraise().  Use one of the priority-raising functions defined in spl(9),
     instead.


SEE ALSO

     condvar(9), mutex(9), rwlock(9), spl(9)

NetBSD 8.1                     February 5, 2010                     NetBSD 8.1