NAME
x86_64_iopl —
change the x86_64 I/O
privilege level
LIBRARY
x86_64 Architecture Library (libx86_64, -lx86_64)
SYNOPSIS
#include <sys/types.h>
#include <machine/sysarch.h>
int
x86_64_iopl(
int
iopl);
DESCRIPTION
x86_64_iopl() sets the x86_64 I/O privilege level to the value
specified by
iopl. This call is restricted to the
super-user.
RETURN VALUES
Upon successful completion,
x86_64_iopl() returns 0.
Otherwise, a value of -1 is returned and the global variable
errno is set to indicate the error.
ERRORS
x86_64_iopl() will fail if:
-
-
- [
EPERM
]
- The caller was not the super-user, or the operation was not
permitted at the current security level.
WARNING
You can really hose your machine if you enable user-level I/O and write to
hardware ports without care.