1/* 2 * Copyright (C) 2012 ARM Ltd. 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License version 2 as 6 * published by the Free Software Foundation. 7 * 8 * This program is distributed in the hope that it will be useful, 9 * but WITHOUT ANY WARRANTY; without even the implied warranty of 10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 11 * GNU General Public License for more details. 12 * 13 * You should have received a copy of the GNU General Public License 14 * along with this program. If not, see <http://www.gnu.org/licenses/>. 15 */ 16 17#include <linux/linkage.h> 18#include <asm/assembler.h> 19 20/* 21 * Copy to user space from a kernel buffer (alignment handled by the hardware) 22 * 23 * Parameters: 24 * x0 - to 25 * x1 - from 26 * x2 - n 27 * Returns: 28 * x0 - bytes not copied 29 */ 30ENTRY(__copy_to_user) 31 add x5, x0, x2 // upper user buffer boundary 32 subs x2, x2, #16 33 b.mi 1f 340: 35 ldp x3, x4, [x1], #16 36 subs x2, x2, #16 37USER(9f, stp x3, x4, [x0], #16) 38 b.pl 0b 391: adds x2, x2, #8 40 b.mi 2f 41 ldr x3, [x1], #8 42 sub x2, x2, #8 43USER(9f, str x3, [x0], #8 ) 442: adds x2, x2, #4 45 b.mi 3f 46 ldr w3, [x1], #4 47 sub x2, x2, #4 48USER(9f, str w3, [x0], #4 ) 493: adds x2, x2, #2 50 b.mi 4f 51 ldrh w3, [x1], #2 52 sub x2, x2, #2 53USER(9f, strh w3, [x0], #2 ) 544: adds x2, x2, #1 55 b.mi 5f 56 ldrb w3, [x1] 57USER(9f, strb w3, [x0] ) 585: mov x0, #0 59 ret 60ENDPROC(__copy_to_user) 61 62 .section .fixup,"ax" 63 .align 2 649: sub x0, x5, x0 // bytes not copied 65 ret 66 .previous 67