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, 3f /* 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, 3f /* 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 88 /* Copy words */ 892: ld a4, 0(a0) /* Load word from src */ 90 addi a0, a0, XLEN_BYTES 91 sd a4, 0(a1) /* Store word in dest */ 92 addi a1, a1, XLEN_BYTES 93 addi a2, a2, -XLEN_BYTES /* len -= XLEN_BYTES */ 94 bgeu a2, t2, 2b /* Again if len >= XLEN_BYTES */ 95 96 /* Check if we're finished */ 97 beqz a2, 4f 98 99 /* Copy any remaining bytes */ 1003: lb a4, 0(a0) /* Load byte from src */ 101 addi a0, a0, 1 102 sb a4, 0(a1) /* Store byte in dest */ 103 addi a1, a1, 1 104 addi a2, a2, -1 /* len-- */ 105 bnez a2, 3b 106 1074: EXIT_USER_ACCESS(a7) 108 SET_FAULT_HANDLER(x0, a7) /* Clear the handler */ 109 .endm 110 111/* 112 * Copies from a kernel to user address 113 * 114 * int copyout(const void *kaddr, void *udaddr, size_t len) 115 */ 116ENTRY(copyout) 117 beqz a2, copyout_end /* If len == 0 then skip loop */ 118 add a3, a1, a2 119 li a4, VM_MAXUSER_ADDRESS 120 bgt a3, a4, copyio_fault_nopcb 121 122 copycommon 123 124copyout_end: 125 li a0, 0 /* return 0 */ 126 ret 127END(copyout) 128 129/* 130 * Copies from a user to kernel address 131 * 132 * int copyin(const void *uaddr, void *kaddr, size_t len) 133 */ 134ENTRY(copyin) 135 beqz a2, copyin_end /* If len == 0 then skip loop */ 136 add a3, a0, a2 137 li a4, VM_MAXUSER_ADDRESS 138 bgt a3, a4, copyio_fault_nopcb 139 140 copycommon 141 142copyin_end: 143 li a0, 0 /* return 0 */ 144 ret 145END(copyin) 146 147/* 148 * Copies a string from a user to kernel address 149 * 150 * int copyinstr(const void *udaddr, void *kaddr, size_t len, size_t *done) 151 */ 152ENTRY(copyinstr) 153 mv a5, x0 /* count = 0 */ 154 beqz a2, 3f /* If len == 0 then skip loop */ 155 156 la a6, copyio_fault /* Get the handler address */ 157 SET_FAULT_HANDLER(a6, a7) /* Set the handler */ 158 ENTER_USER_ACCESS(a7) 159 160 li a7, VM_MAXUSER_ADDRESS 1611: bgt a0, a7, copyio_fault 162 lb a4, 0(a0) /* Load from uaddr */ 163 addi a0, a0, 1 164 sb a4, 0(a1) /* Store in kaddr */ 165 addi a1, a1, 1 166 beqz a4, 2f 167 addi a2, a2, -1 /* len-- */ 168 addi a5, a5, 1 /* count++ */ 169 bnez a2, 1b 170 1712: EXIT_USER_ACCESS(a7) 172 SET_FAULT_HANDLER(x0, a7) /* Clear the handler */ 173 1743: beqz a3, 4f /* Check if done != NULL */ 175 addi a5, a5, 1 /* count++ */ 176 sd a5, 0(a3) /* done = count */ 177 1784: mv a0, x0 /* return 0 */ 179 beqz a4, 5f 180 li a0, ENAMETOOLONG 1815: 182 ret 183END(copyinstr) 184