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copyinstr.c revision 1.2 
      1 /*	$NetBSD: copyinstr.c,v 1.2 2002/07/11 01:38:48 simonb 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/param.h>
     39 #include <uvm/uvm_extern.h>
     40 #include <machine/pcb.h>
     41 
     42 int setfault(faultbuf);		/* defined in locore.S */
     43 
     44 int
     45 copyinstr(const void *udaddr, void *kaddr, size_t len, size_t *done)
     46 {
     47 	struct pmap *pm = curproc->p_vmspace->vm_map.pmap;
     48 	int msr, pid, tmp, ctx;
     49 	faultbuf env;
     50 
     51 	if (setfault(env)) {
     52 		curpcb->pcb_onfault = 0;
     53 		/* XXXX -- len may be lost on a fault */
     54 		if (done)
     55 			*done = len;
     56 		return EFAULT;
     57 	}
     58 
     59 	if (!(ctx = pm->pm_ctx)) {
     60 		/* No context -- assign it one */
     61 		ctx_alloc(pm);
     62 		ctx = pm->pm_ctx;
     63 	}
     64 
     65 	if (len) {
     66 		asm volatile("mtctr %3;"		/* Set up counter */
     67 			"mfmsr %0;"			/* Save MSR */
     68 			"li %1,0x20; "
     69 			"andc %1,%0,%1; mtmsr %1;"	/* Disable IMMU */
     70 			"mfpid %1;"			/* Save old PID */
     71 			"sync; isync;"
     72 
     73 			"li %3,0;"			/* Clear len */
     74 
     75 			"1: "
     76 			"mtpid %4; sync;"		/* Load user ctx */
     77 			"lbz %2,0(%5); addi %5,%5,1;"	/* Load byte */
     78 			"sync; isync;"
     79 			"mtpid %1;sync;"
     80 			"stb %2,0(%6);  dcbf 0,%6; addi %6,%6,1;"	/* Store kernel byte */
     81 			"sync; isync;"
     82 			"addi %3,%3,1;"			/* Inc len */
     83 			"or. %2,%2,%2;"
     84 			"bdnzf 2,1b;"			/*
     85 							 * while(ctr-- && !zero)
     86 							 */
     87 
     88 			"2: mtpid %1; mtmsr %0;"	/* Restore PID, MSR */
     89 			"sync; isync;"
     90 			: "=&r" (msr), "=&r" (pid), "=&r" (tmp), "+r" (len)
     91 			: "r" (ctx), "r" (udaddr), "r" (kaddr));
     92 	}
     93 	curpcb->pcb_onfault = 0;
     94 	if (done)
     95 		*done = len;
     96 	return 0;
     97 }
     98