| Greentime Hu | ace02e2 | 2017-10-25 14:27:22 +0800 | [diff] [blame] | 1 | // SPDX-License-Identifier: GPL-2.0 |
| 2 | // Copyright (C) 2005-2017 Andes Technology Corporation |
| 3 | |
| 4 | #include <linux/linkage.h> |
| 5 | #include <asm/assembler.h> |
| 6 | #include <asm/errno.h> |
| 7 | |
| 8 | /* Prototype: int __arch_clear_user(void *addr, size_t sz) |
| 9 | * Purpose : clear some user memory |
| 10 | * Params : addr - user memory address to clear |
| 11 | * : sz - number of bytes to clear |
| 12 | * Returns : number of bytes NOT cleared |
| 13 | */ |
| 14 | .text |
| 15 | .align 5 |
| 16 | ENTRY(__arch_clear_user) |
| 17 | add $r5, $r0, $r1 |
| 18 | beqz $r1, clear_exit |
| 19 | xor $p1, $p1, $p1 ! Use $p1=0 to clear mem |
| 20 | srli $p0, $r1, #2 ! $p0 = number of word to clear |
| 21 | andi $r1, $r1, #3 ! Bytes less than a word to copy |
| 22 | beqz $p0, byte_clear ! Only less than a word to clear |
| 23 | word_clear: |
| 24 | USER( smw.bim,$p1, [$r0], $p1) ! Clear the word |
| 25 | addi $p0, $p0, #-1 ! Decrease word count |
| 26 | bnez $p0, word_clear ! Continue looping to clear all words |
| 27 | beqz $r1, clear_exit ! No left bytes to copy |
| 28 | byte_clear: |
| 29 | USER( sbi.bi, $p1, [$r0], #1) ! Clear the byte |
| 30 | addi $r1, $r1, #-1 ! Decrease byte count |
| 31 | bnez $r1, byte_clear ! Continue looping to clear all left bytes |
| 32 | clear_exit: |
| 33 | move $r0, $r1 ! Set return value |
| 34 | ret |
| 35 | |
| 36 | .section .fixup,"ax" |
| 37 | .align 0 |
| 38 | 9001: |
| 39 | sub $r0, $r5, $r0 ! Bytes left to copy |
| 40 | ret |
| 41 | .previous |
| 42 | ENDPROC(__arch_clear_user) |