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__FBSDID("$FreeBSD$"); 38 39#include <machine/riscvreg.h> 40#include <sys/errno.h> 41 42#include "assym.inc" 43 44/* 45 * Fault handler for the copy{in,out} functions below. 46 */ 47ENTRY(copyio_fault) 48 SET_FAULT_HANDLER(x0, a1) /* Clear the handler */ 49 EXIT_USER_ACCESS(a1) 50copyio_fault_nopcb: 51 li a0, EFAULT 52 ret 53END(copyio_fault) 54 55/* 56 * copycommon - common copy routine 57 * 58 * a0 - Source address 59 * a1 - Destination address 60 * a2 - Size of copy 61 */ 62 .macro copycommon 63 la a6, copyio_fault /* Get the handler address */ 64 SET_FAULT_HANDLER(a6, a7) /* Set the handler */ 65 ENTER_USER_ACCESS(a7) 66 67 li t2, XLEN_BYTES 68 blt a2, t2, 4f /* Byte-copy if len < XLEN_BYTES */ 69 70 /* 71 * Compare lower bits of src and dest. 72 * If they are aligned with each other, we can do word copy. 73 */ 74 andi t0, a0, (XLEN_BYTES-1) /* Low bits of src */ 75 andi t1, a1, (XLEN_BYTES-1) /* Low bits of dest */ 76 bne t0, t1, 4f /* Misaligned. Go to byte copy */ 77 beqz t0, 2f /* Already word-aligned, skip ahead */ 78 79 /* Byte copy until the first word-aligned address */ 801: lb a4, 0(a0) /* Load byte from src */ 81 addi a0, a0, 1 82 sb a4, 0(a1) /* Store byte in dest */ 83 addi a1, a1, 1 84 addi a2, a2, -1 /* len-- */ 85 andi t0, a0, (XLEN_BYTES-1) 86 bnez t0, 1b 87 j 3f 88 89 /* Copy words */ 902: ld a4, 0(a0) /* Load word from src */ 91 addi a0, a0, XLEN_BYTES 92 sd a4, 0(a1) /* Store word in dest */ 93 addi a1, a1, XLEN_BYTES 94 addi a2, a2, -XLEN_BYTES /* len -= XLEN_BYTES */ 953: bgeu a2, t2, 2b /* Again if len >= XLEN_BYTES */ 96 97 /* Check if we're finished */ 98 beqz a2, 5f 99 100 /* Copy any remaining bytes */ 1014: lb a4, 0(a0) /* Load byte from src */ 102 addi a0, a0, 1 103 sb a4, 0(a1) /* Store byte in dest */ 104 addi a1, a1, 1 105 addi a2, a2, -1 /* len-- */ 106 bnez a2, 4b 107 1085: EXIT_USER_ACCESS(a7) 109 SET_FAULT_HANDLER(x0, a7) /* Clear the handler */ 110 .endm 111 112/* 113 * Copies from a kernel to user address 114 * 115 * int copyout(const void *kaddr, void *udaddr, size_t len) 116 */ 117ENTRY(copyout) 118 beqz a2, copyout_end /* If len == 0 then skip loop */ 119 add a3, a1, a2 120 li a4, VM_MAXUSER_ADDRESS 121 bgeu a3, a4, copyio_fault_nopcb 122 123 copycommon 124 125copyout_end: 126 li a0, 0 /* return 0 */ 127 ret 128END(copyout) 129 130/* 131 * Copies from a user to kernel address 132 * 133 * int copyin(const void *uaddr, void *kaddr, size_t len) 134 */ 135ENTRY(copyin) 136 beqz a2, copyin_end /* If len == 0 then skip loop */ 137 add a3, a0, a2 138 li a4, VM_MAXUSER_ADDRESS 139 bgeu a3, a4, copyio_fault_nopcb 140 141 copycommon 142 143copyin_end: 144 li a0, 0 /* return 0 */ 145 ret 146END(copyin) 147 148/* 149 * Copies a string from a user to kernel address 150 * 151 * int copyinstr(const void *udaddr, void *kaddr, size_t len, size_t *done) 152 */ 153ENTRY(copyinstr) 154 mv a5, x0 /* count = 0 */ 155 beqz a2, 3f /* If len == 0 then skip loop */ 156 157 la a6, copyio_fault /* Get the handler address */ 158 SET_FAULT_HANDLER(a6, a7) /* Set the handler */ 159 ENTER_USER_ACCESS(a7) 160 161 li a7, VM_MAXUSER_ADDRESS 1621: bgeu a0, a7, copyio_fault 163 lb a4, 0(a0) /* Load from uaddr */ 164 addi a0, a0, 1 165 sb a4, 0(a1) /* Store in kaddr */ 166 addi a1, a1, 1 167 beqz a4, 2f 168 addi a2, a2, -1 /* len-- */ 169 addi a5, a5, 1 /* count++ */ 170 bnez a2, 1b 171 1722: EXIT_USER_ACCESS(a7) 173 SET_FAULT_HANDLER(x0, a7) /* Clear the handler */ 174 1753: beqz a3, 4f /* Check if done != NULL */ 176 addi a5, a5, 1 /* count++ */ 177 sd a5, 0(a3) /* done = count */ 178 1794: mv a0, x0 /* return 0 */ 180 beqz a4, 5f 181 li a0, ENAMETOOLONG 1825: 183 ret 184END(copyinstr) 185