Quelle  uaccess.c   Sprache: C

/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 2009, Wind River Systems Inc
 * Implemented by fredrik.markstrom@gmail.com and ivarholmqvist@gmail.com
 */

#include <linux/export.h>
#include <linux/uaccess.h>

asm(".global raw_copy_from_user\n"
 " .type raw_copy_from_user, @function\n"
 "raw_copy_from_user:\n"
 " movi r2,7\n"
 " mov r3,r4\n"
 " bge r2,r6,1f\n"
 " xor r2,r4,r5\n"
 " andi r2,r2,3\n"
 " movi r7,3\n"
 " beq r2,zero,4f\n"
 "1: addi r6,r6,-1\n"
 " movi r2,-1\n"
 " beq r6,r2,3f\n"
 " mov r7,r2\n"
 "2: ldbu r2,0(r5)\n"
 " addi r6,r6,-1\n"
 " addi r5,r5,1\n"
 " stb r2,0(r3)\n"
 " addi r3,r3,1\n"
 " bne r6,r7,2b\n"
 "3:\n"
 " addi r2,r6,1\n"
 " ret\n"
 "13:mov r2,r6\n"
 " ret\n"
 "4: andi r2,r4,1\n"
 " cmpeq r2,r2,zero\n"
 " beq r2,zero,7f\n"
 "5: andi r2,r3,2\n"
 " beq r2,zero,6f\n"
 "9: ldhu r2,0(r5)\n"
 " addi r6,r6,-2\n"
 " addi r5,r5,2\n"
 " sth r2,0(r3)\n"
 " addi r3,r3,2\n"
 "6: bge r7,r6,1b\n"
 "10:ldw r2,0(r5)\n"
 " addi r6,r6,-4\n"
 " addi r5,r5,4\n"
 " stw r2,0(r3)\n"
 " addi r3,r3,4\n"
 " br 6b\n"
 "7: ldbu r2,0(r5)\n"
 " addi r6,r6,-1\n"
 " addi r5,r5,1\n"
 " addi r3,r4,1\n"
 " stb r2,0(r4)\n"
 " br 5b\n"
 ".section __ex_table,\"a\"\n"
 ".word 2b,3b\n"
 ".word 9b,13b\n"
 ".word 10b,13b\n"
 ".word 7b,13b\n"
 ".previous\n"
 );
EXPORT_SYMBOL(raw_copy_from_user);

asm(
 " .global raw_copy_to_user\n"
 " .type raw_copy_to_user, @function\n"
 "raw_copy_to_user:\n"
 " movi r2,7\n"
 " mov r3,r4\n"
 " bge r2,r6,1f\n"
 " xor r2,r4,r5\n"
 " andi r2,r2,3\n"
 " movi r7,3\n"
 " beq r2,zero,4f\n"
 /* Bail if we try to copy zero bytes  */
 "1: addi r6,r6,-1\n"
 " movi r2,-1\n"
 " beq r6,r2,3f\n"
 /* Copy byte by byte for small copies and if src^dst != 0 */
 " mov r7,r2\n"
 "2: ldbu r2,0(r5)\n"
 " addi r5,r5,1\n"
 "9: stb r2,0(r3)\n"
 " addi r6,r6,-1\n"
 " addi r3,r3,1\n"
 " bne r6,r7,2b\n"
 "3: addi r2,r6,1\n"
 " ret\n"
 "13:mov r2,r6\n"
 " ret\n"
 /*  If 'to' is an odd address byte copy */
 "4: andi r2,r4,1\n"
 " cmpeq r2,r2,zero\n"
 " beq r2,zero,7f\n"
 /* If 'to' is not divideable by four copy halfwords */
 "5: andi r2,r3,2\n"
 " beq r2,zero,6f\n"
 " ldhu r2,0(r5)\n"
 " addi r5,r5,2\n"
 "10:sth r2,0(r3)\n"
 " addi r6,r6,-2\n"
 " addi r3,r3,2\n"
 /* Copy words */
 "6: bge r7,r6,1b\n"
 " ldw r2,0(r5)\n"
 " addi r5,r5,4\n"
 "11:stw r2,0(r3)\n"
 " addi r6,r6,-4\n"
 " addi r3,r3,4\n"
 " br 6b\n"
 /* Copy remaining bytes */
 "7: ldbu r2,0(r5)\n"
 " addi r5,r5,1\n"
 " addi r3,r4,1\n"
 "12: stb r2,0(r4)\n"
 " addi r6,r6,-1\n"
 " br 5b\n"
 ".section __ex_table,\"a\"\n"
 ".word 9b,3b\n"
 ".word 10b,13b\n"
 ".word 11b,13b\n"
 ".word 12b,13b\n"
 ".previous\n");
EXPORT_SYMBOL(raw_copy_to_user);