1/*- 2 * Copyright (c) 2015-2018 Ruslan Bukin <br@bsdpad.com> 3 * Copyright (c) 2019 Mitchell Horne 4 * All rights reserved. 5 * 6 * Portions of this software were developed by SRI International and the 7 * University of Cambridge Computer Laboratory under DARPA/AFRL contract 8 * FA8750-10-C-0237 ("CTSRD"), as part of the DARPA CRASH research programme. 9 * 10 * Portions of this software were developed by the University of Cambridge 11 * Computer Laboratory as part of the CTSRD Project, with support from the 12 * UK Higher Education Innovation Fund (HEIF). 13 * 14 * Redistribution and use in source and binary forms, with or without 15 * modification, are permitted provided that the following conditions 16 * are met: 17 * 1. Redistributions of source code must retain the above copyright 18 * notice, this list of conditions and the following disclaimer. 19 * 2. Redistributions in binary form must reproduce the above copyright 20 * notice, this list of conditions and the following disclaimer in the 21 * documentation and/or other materials provided with the distribution. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36#include <machine/asm.h> 37#include <machine/riscvreg.h> 38#include <sys/errno.h> 39 40#include "assym.inc" 41 42/* 43 * Fault handler for the copy{in,out} functions below. 44 */ 45ENTRY(copyio_fault) 46 SET_FAULT_HANDLER(x0, a1) /* Clear the handler */ 47 EXIT_USER_ACCESS(a1) 48copyio_fault_nopcb: 49 li a0, EFAULT 50 ret 51END(copyio_fault) 52 53/* 54 * copycommon - common copy routine 55 * 56 * a0 - Source address 57 * a1 - Destination address 58 * a2 - Size of copy 59 */ 60 .macro copycommon 61 la a6, copyio_fault /* Get the handler address */ 62 SET_FAULT_HANDLER(a6, a7) /* Set the handler */ 63 ENTER_USER_ACCESS(a7) 64 65 li t2, XLEN_BYTES 66 blt a2, t2, 4f /* Byte-copy if len < XLEN_BYTES */ 67 68 /* 69 * Compare lower bits of src and dest. 70 * If they are aligned with each other, we can do word copy. 71 */ 72 andi t0, a0, (XLEN_BYTES-1) /* Low bits of src */ 73 andi t1, a1, (XLEN_BYTES-1) /* Low bits of dest */ 74 bne t0, t1, 4f /* Misaligned. Go to byte copy */ 75 beqz t0, 2f /* Already word-aligned, skip ahead */ 76 77 /* Byte copy until the first word-aligned address */ 781: lb a4, 0(a0) /* Load byte from src */ 79 addi a0, a0, 1 80 sb a4, 0(a1) /* Store byte in dest */ 81 addi a1, a1, 1 82 addi a2, a2, -1 /* len-- */ 83 andi t0, a0, (XLEN_BYTES-1) 84 bnez t0, 1b 85 j 3f 86 87 /* Copy words */ 882: ld a4, 0(a0) /* Load word from src */ 89 addi a0, a0, XLEN_BYTES 90 sd a4, 0(a1) /* Store word in dest */ 91 addi a1, a1, XLEN_BYTES 92 addi a2, a2, -XLEN_BYTES /* len -= XLEN_BYTES */ 933: bgeu a2, t2, 2b /* Again if len >= XLEN_BYTES */ 94 95 /* Check if we're finished */ 96 beqz a2, 5f 97 98 /* Copy any remaining bytes */ 994: lb a4, 0(a0) /* Load byte from src */ 100 addi a0, a0, 1 101 sb a4, 0(a1) /* Store byte in dest */ 102 addi a1, a1, 1 103 addi a2, a2, -1 /* len-- */ 104 bnez a2, 4b 105 1065: EXIT_USER_ACCESS(a7) 107 SET_FAULT_HANDLER(x0, a7) /* Clear the handler */ 108 .endm 109 110/* 111 * Copies from a kernel to user address 112 * 113 * int copyout(const void *kaddr, void *udaddr, size_t len) 114 */ 115ENTRY(copyout) 116 beqz a2, copyout_end /* If len == 0 then skip loop */ 117 add a3, a1, a2 118 li a4, VM_MAXUSER_ADDRESS 119 bgeu a3, a4, copyio_fault_nopcb 120 121 copycommon 122 123copyout_end: 124 li a0, 0 /* return 0 */ 125 ret 126END(copyout) 127 128/* 129 * Copies from a user to kernel address 130 * 131 * int copyin(const void *uaddr, void *kaddr, size_t len) 132 */ 133ENTRY(copyin) 134 beqz a2, copyin_end /* If len == 0 then skip loop */ 135 add a3, a0, a2 136 li a4, VM_MAXUSER_ADDRESS 137 bgeu a3, a4, copyio_fault_nopcb 138 139 copycommon 140 141copyin_end: 142 li a0, 0 /* return 0 */ 143 ret 144END(copyin) 145 146/* 147 * Copies a string from a user to kernel address 148 * 149 * int copyinstr(const void *udaddr, void *kaddr, size_t len, size_t *done) 150 */ 151ENTRY(copyinstr) 152 mv a5, x0 /* count = 0 */ 153 beqz a2, 3f /* If len == 0 then skip loop */ 154 155 la a6, copyio_fault /* Get the handler address */ 156 SET_FAULT_HANDLER(a6, a7) /* Set the handler */ 157 ENTER_USER_ACCESS(a7) 158 159 li a7, VM_MAXUSER_ADDRESS 1601: bgeu a0, a7, copyio_fault 161 lb a4, 0(a0) /* Load from uaddr */ 162 addi a0, a0, 1 163 sb a4, 0(a1) /* Store in kaddr */ 164 addi a1, a1, 1 165 beqz a4, 2f 166 addi a2, a2, -1 /* len-- */ 167 addi a5, a5, 1 /* count++ */ 168 bnez a2, 1b 169 1702: EXIT_USER_ACCESS(a7) 171 SET_FAULT_HANDLER(x0, a7) /* Clear the handler */ 172 1733: beqz a3, 4f /* Check if done != NULL */ 174 addi a5, a5, 1 /* count++ */ 175 sd a5, 0(a3) /* done = count */ 176 1774: mv a0, x0 /* return 0 */ 178 beqz a4, 5f 179 li a0, ENAMETOOLONG 1805: 181 ret 182END(copyinstr) 183