copyinstr.c revision 1.17
1/* $NetBSD: copyinstr.c,v 1.17 2022/10/03 23:35:41 rin 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 1.17 2022/10/03 23:35:41 rin Exp $"); 40 41#include <sys/param.h> 42#include <uvm/uvm_extern.h> 43#include <powerpc/ibm4xx/spr.h> 44#include <machine/pcb.h> 45 46int 47copyinstr(const void *uaddr, void *kaddr, size_t len, size_t *done) 48{ 49 struct pmap *pm = curproc->p_vmspace->vm_map.pmap; 50 size_t resid; 51 int rv, msr, pid, data, ctx; 52 struct faultbuf env; 53 54 if (__predict_false(len == 0)) { 55 if (done) 56 *done = 0; 57 return 0; 58 } 59 60 if ((rv = setfault(&env))) { 61 curpcb->pcb_onfault = NULL; 62 if (done) 63 *done = 0; 64 return rv; 65 } 66 67 if (!(ctx = pm->pm_ctx)) { 68 /* No context -- assign it one */ 69 ctx_alloc(pm); 70 ctx = pm->pm_ctx; 71 } 72 73 resid = len; 74 __asm volatile( 75 "mtctr %[resid];" /* Set up counter */ 76 77 "mfmsr %[msr];" /* Save MSR */ 78 79 "li %[pid],0x20;" /* Disable IMMU */ 80 "andc %[pid],%[msr],%[pid];" 81 "mtmsr %[pid];" 82 "isync;" 83 84 MFPID(%[pid]) /* Save old PID */ 85 86 "1:" MTPID(%[ctx]) /* Load user ctx */ 87 "isync;" 88 "lbz %[data],0(%[uaddr]);" /* Load byte */ 89 "addi %[uaddr],%[uaddr],1;" 90 "sync;" 91 92 MTPID(%[pid]) 93 "isync;" 94 "stb %[data],0(%[kaddr]);" /* Store kernel byte */ 95 "dcbst 0,%[kaddr];" 96 "addi %[kaddr],%[kaddr],1;" 97 "or. %[data],%[data],%[data];" 98 "sync;" 99 100 "bdnzf eq,1b;" /* while(ctr-- && !zero) */ 101 102 MTPID(%[pid]) /* Restore PID, MSR */ 103 "mtmsr %[msr];" 104 "isync;" 105 106 "mfctr %[resid];" /* Restore resid */ 107 108 : [msr] "=&r" (msr), [pid] "=&r" (pid), [data] "=&r" (data), 109 [resid] "+r" (resid) 110 : [ctx] "r" (ctx), [uaddr] "b" (uaddr), [kaddr] "b" (kaddr)); 111 112 curpcb->pcb_onfault = NULL; 113 if (done) 114 *done = len - resid; 115 if (resid == 0 && (char)data != '\0') 116 return ENAMETOOLONG; 117 else 118 return 0; 119} 120