1 /* $NetBSD: copyoutstr.c,v 1.11 2020/03/05 01:10:57 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: copyoutstr.c,v 1.11 2020/03/05 01:10:57 rin Exp $"); 40 41 #include <sys/param.h> 42 #include <uvm/uvm_extern.h> 43 #include <machine/pcb.h> 44 45 int 46 copyoutstr(const void *kaddr, void *udaddr, size_t len, size_t *done) 47 { 48 struct pmap *pm = curproc->p_vmspace->vm_map.pmap; 49 size_t resid; 50 int rv, msr, pid, data, ctx; 51 struct faultbuf env; 52 53 if (__predict_false(len == 0)) { 54 if (done) 55 *done = 0; 56 return 0; 57 } 58 59 if ((rv = setfault(&env))) { 60 curpcb->pcb_onfault = NULL; 61 if (done) 62 *done = 0; 63 return rv; 64 } 65 66 if (!(ctx = pm->pm_ctx)) { 67 /* No context -- assign it one */ 68 ctx_alloc(pm); 69 ctx = pm->pm_ctx; 70 } 71 72 resid = len; 73 __asm volatile( 74 "mtctr %3;" /* Set up counter */ 75 "mfmsr %0;" /* Save MSR */ 76 "li %1,0x20;" 77 "andc %1,%0,%1; mtmsr %1;" /* Disable IMMU */ 78 "mfpid %1;" /* Save old PID */ 79 "sync; isync;" 80 81 "1:" 82 "mtpid %1;sync;" 83 "lbz %2,0(%6); addi %6,%6,1;" /* Store kernel byte */ 84 "sync; isync;" 85 "mtpid %4; sync;" /* Load user ctx */ 86 "stb %2,0(%5); dcbf 0,%5; addi %5,%5,1;" 87 /* Load byte */ 88 "sync; isync;" 89 "or. %2,%2,%2;" 90 "bdnzf 2,1b;" /* while(ctr-- && !zero) */ 91 92 "mtpid %1; mtmsr %0;" /* Restore PID, MSR */ 93 "sync; isync;" 94 "mfctr %3;" /* Restore resid */ 95 : "=&r" (msr), "=&r" (pid), "=&r" (data), "+r" (resid) 96 : "r" (ctx), "b" (udaddr), "b" (kaddr)); 97 98 curpcb->pcb_onfault = NULL; 99 if (done) 100 *done = len - resid; 101 if (resid == 0 && (char)data != '\0') 102 return ENAMETOOLONG; 103 else 104 return 0; 105 } 106