2.11BSD#431 - /usr/man/cat2/ucall.0

UCALL(2)	    UNIX Programmer's Manual		 UCALL(2)


NAME
     ucall - call a kernel subroutine from user mode (2BSD)

SYNOPSIS
     #include <pdp/psl.h>
     #include <sys/types.h>

     ucall(priority, function, arg0, arg1)
     int priority, arg0, arg1;
     caddr_t function;

DESCRIPTION
     Ucall causes the processor priority to be set to priority
     and the specified kernel function to be called with argu-
     ments arg0 and arg1.  Priority is one of PSL_BR0, ...,
     PSL_BR7.  Processor priority is reset to PSL_BR0 when func-
     tion returns.

     Ucall is allowed only if the user is the superuser.  It is
     obviously extremely dangerous if misused.	It's only current
     use is at system boot time to configure system devices by
     calling device drivers ...

ERRORS
     [EPERM]	    The caller is not the super-user.

SEE ALSO
     autoconfig(8)

BUGS
     No address validations are attempted.

     Ucall is unique to the PDP-11 and 2BSD; its use is
     discouraged.


Printed 11/26/99	January 22, 1987			1