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/*-
* Copyright (c) 2015-2018 Ruslan Bukin <br@bsdpad.com>
* Copyright (c) 2019 Mitchell Horne
* All rights reserved.
*
* Portions of this software were developed by SRI International and the
* University of Cambridge Computer Laboratory under DARPA/AFRL contract
* FA8750-10-C-0237 ("CTSRD"), as part of the DARPA CRASH research programme.
*
* Portions of this software were developed by the University of Cambridge
* Computer Laboratory as part of the CTSRD Project, with support from the
* UK Higher Education Innovation Fund (HEIF).
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <machine/asm.h>
__FBSDID("$FreeBSD$");
#include <machine/riscvreg.h>
#include <sys/errno.h>
#include "assym.inc"
/*
* Fault handler for the copy{in,out} functions below.
*/
ENTRY(copyio_fault)
SET_FAULT_HANDLER(x0, a1) /* Clear the handler */
EXIT_USER_ACCESS(a1)
copyio_fault_nopcb:
li a0, EFAULT
ret
END(copyio_fault)
/*
* copycommon - common copy routine
*
* a0 - Source address
* a1 - Destination address
* a2 - Size of copy
*/
.macro copycommon
la a6, copyio_fault /* Get the handler address */
SET_FAULT_HANDLER(a6, a7) /* Set the handler */
ENTER_USER_ACCESS(a7)
li t2, XLEN_BYTES
blt a2, t2, 4f /* Byte-copy if len < XLEN_BYTES */
/*
* Compare lower bits of src and dest.
* If they are aligned with each other, we can do word copy.
*/
andi t0, a0, (XLEN_BYTES-1) /* Low bits of src */
andi t1, a1, (XLEN_BYTES-1) /* Low bits of dest */
bne t0, t1, 4f /* Misaligned. Go to byte copy */
beqz t0, 2f /* Already word-aligned, skip ahead */
/* Byte copy until the first word-aligned address */
1: lb a4, 0(a0) /* Load byte from src */
addi a0, a0, 1
sb a4, 0(a1) /* Store byte in dest */
addi a1, a1, 1
addi a2, a2, -1 /* len-- */
andi t0, a0, (XLEN_BYTES-1)
bnez t0, 1b
j 3f
/* Copy words */
2: ld a4, 0(a0) /* Load word from src */
addi a0, a0, XLEN_BYTES
sd a4, 0(a1) /* Store word in dest */
addi a1, a1, XLEN_BYTES
addi a2, a2, -XLEN_BYTES /* len -= XLEN_BYTES */
3: bgeu a2, t2, 2b /* Again if len >= XLEN_BYTES */
/* Check if we're finished */
beqz a2, 5f
/* Copy any remaining bytes */
4: lb a4, 0(a0) /* Load byte from src */
addi a0, a0, 1
sb a4, 0(a1) /* Store byte in dest */
addi a1, a1, 1
addi a2, a2, -1 /* len-- */
bnez a2, 4b
5: EXIT_USER_ACCESS(a7)
SET_FAULT_HANDLER(x0, a7) /* Clear the handler */
.endm
/*
* Copies from a kernel to user address
*
* int copyout(const void *kaddr, void *udaddr, size_t len)
*/
ENTRY(copyout)
beqz a2, copyout_end /* If len == 0 then skip loop */
add a3, a1, a2
li a4, VM_MAXUSER_ADDRESS
bgeu a3, a4, copyio_fault_nopcb
copycommon
copyout_end:
li a0, 0 /* return 0 */
ret
END(copyout)
/*
* Copies from a user to kernel address
*
* int copyin(const void *uaddr, void *kaddr, size_t len)
*/
ENTRY(copyin)
beqz a2, copyin_end /* If len == 0 then skip loop */
add a3, a0, a2
li a4, VM_MAXUSER_ADDRESS
bgeu a3, a4, copyio_fault_nopcb
copycommon
copyin_end:
li a0, 0 /* return 0 */
ret
END(copyin)
/*
* Copies a string from a user to kernel address
*
* int copyinstr(const void *udaddr, void *kaddr, size_t len, size_t *done)
*/
ENTRY(copyinstr)
mv a5, x0 /* count = 0 */
beqz a2, 3f /* If len == 0 then skip loop */
la a6, copyio_fault /* Get the handler address */
SET_FAULT_HANDLER(a6, a7) /* Set the handler */
ENTER_USER_ACCESS(a7)
li a7, VM_MAXUSER_ADDRESS
1: bgeu a0, a7, copyio_fault
lb a4, 0(a0) /* Load from uaddr */
addi a0, a0, 1
sb a4, 0(a1) /* Store in kaddr */
addi a1, a1, 1
beqz a4, 2f
addi a2, a2, -1 /* len-- */
addi a5, a5, 1 /* count++ */
bnez a2, 1b
2: EXIT_USER_ACCESS(a7)
SET_FAULT_HANDLER(x0, a7) /* Clear the handler */
3: beqz a3, 4f /* Check if done != NULL */
addi a5, a5, 1 /* count++ */
sd a5, 0(a3) /* done = count */
4: mv a0, x0 /* return 0 */
beqz a4, 5f
li a0, ENAMETOOLONG
5:
ret
END(copyinstr)
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