copyinstr.c revision 1.6 
1/*	$NetBSD: copyinstr.c,v 1.6 2004/09/02 08:22:58 scw Exp $	*/
2
3/*
4 * Copyright 2001 Wasabi Systems, Inc.
5 * All rights reserved.
6 *
7 * Written by Eduardo Horvath and Simon Burge for Wasabi Systems, Inc.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 *    notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 *    notice, this list of conditions and the following disclaimer in the
16 *    documentation and/or other materials provided with the distribution.
17 * 3. All advertising materials mentioning features or use of this software
18 *    must display the following acknowledgement:
19 *      This product includes software developed for the NetBSD Project by
20 *      Wasabi Systems, Inc.
21 * 4. The name of Wasabi Systems, Inc. may not be used to endorse
22 *    or promote products derived from this software without specific prior
23 *    written permission.
24 *
25 * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND
26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
27 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
28 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL WASABI SYSTEMS, INC
29 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
30 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
31 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
32 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
33 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
34 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
35 * POSSIBILITY OF SUCH DAMAGE.
36 */
37
38#include <sys/cdefs.h>
39__KERNEL_RCSID(0, "$NetBSD: copyinstr.c,v 1.6 2004/09/02 08:22:58 scw Exp $");
40
41#include <sys/param.h>
42#include <uvm/uvm_extern.h>
43#include <machine/pcb.h>
44
45int
46copyinstr(const void *udaddr, void *kaddr, size_t len, size_t *done)
47{
48	struct pmap *pm = curproc->p_vmspace->vm_map.pmap;
49	int msr, pid, tmp, ctx;
50	struct faultbuf env;
51
52	if (setfault(&env)) {
53		curpcb->pcb_onfault = 0;
54		/* XXXX -- len may be lost on a fault */
55		if (done)
56			*done = len;
57		return EFAULT;
58	}
59
60	if (!(ctx = pm->pm_ctx)) {
61		/* No context -- assign it one */
62		ctx_alloc(pm);
63		ctx = pm->pm_ctx;
64	}
65
66	if (len) {
67		asm volatile("mtctr %3;"		/* Set up counter */
68			"mfmsr %0;"			/* Save MSR */
69			"li %1,0x20; "
70			"andc %1,%0,%1; mtmsr %1;"	/* Disable IMMU */
71			"mfpid %1;"			/* Save old PID */
72			"sync; isync;"
73
74			"li %3,0;"			/* Clear len */
75
76			"1: "
77			"mtpid %4; sync;"		/* Load user ctx */
78			"lbz %2,0(%5); addi %5,%5,1;"	/* Load byte */
79			"sync; isync;"
80			"mtpid %1;sync;"
81			"stb %2,0(%6);  dcbf 0,%6; addi %6,%6,1;"	/* Store kernel byte */
82			"sync; isync;"
83			"addi %3,%3,1;"			/* Inc len */
84			"or. %2,%2,%2;"
85			"bdnzf 2,1b;"			/*
86							 * while(ctr-- && !zero)
87							 */
88
89			"mtpid %1; mtmsr %0;"		/* Restore PID, MSR */
90			"sync; isync;"
91			: "=&r" (msr), "=&r" (pid), "=&r" (tmp), "+b" (len)
92			: "r" (ctx), "b" (udaddr), "b" (kaddr));
93	}
94	curpcb->pcb_onfault = 0;
95	if (done)
96		*done = len;
97	return 0;
98}
99