cachectl.2

来自「<B>Digital的Unix操作系统VAX 4.2源码</B>」· 2 代码 · 共 75 行

.TH cachectl 2 RISC
.UC 4
.SH Name
cachectl \- mark pages cacheable or uncacheable
.SH Syntax
.ft B
.nf
#include <mips/cachectl.h>
.sp
cachectl(addr, nbytes, op)
char *addr;
int nbytes, op;
.fi
.ft R
.SH Description
The
.PN cachectl
system call allows a process to make
ranges of its address space cacheable or uncacheable.
Initially, a process's entire address space is cacheable.
.PP
The 
.I op
parameter is one of the following:
.TP 20
CACHEABLE
Make the indicated pages cacheable.
.TP 20
UNCACHEABLE
Make the indicated pages uncacheable.
.PP
The arguments CACHEABLE and UNCACHEABLE affect the address range
indicated by the
.I addr
and
.IR nbytes
parameters.
The
.I addr
must be page aligned, and
.I nbytes
must be a multiple of the page size.
.PP
Changing a page from UNCACHEABLE state to CACHEABLE
state causes both the instruction and data caches to be flushed. 
.SH Return Values
The
.PN cachectl
system call returns 0 on success. If errors are 
detected, the
.PN cachectl
system call returns \-1 with the error cause indicated in
.IR errno.
.SH Diagnostics
.TP 15
[EFAULT]
Some or all of the address range
.I addr
to
.RI ( addr + nbytes \-1)
are not accessible.
.TP 15
[EINVAL]
The
.I op
parameter is not CACHEABLE or UNCACHEABLE. 
.TP 15
[EINVAL]
The 
.I addr
parameter is not page aligned,
or the
.I nbytes
parameter is not a multiple of pagesize.