1/* SPDX-License-Identifier: GPL-2.0-only */ 2/* 3 * linux/arch/unicore32/lib/clear_user.S 4 * 5 * Code specific to PKUnity SoC and UniCore ISA 6 * 7 * Copyright (C) 2001-2010 GUAN Xue-tao 8 */ 9#include <linux/linkage.h> 10#include <asm/assembler.h> 11 12 .text 13 14/* Prototype: int __clear_user(void *addr, size_t sz) 15 * Purpose : clear some user memory 16 * Params : addr - user memory address to clear 17 * : sz - number of bytes to clear 18 * Returns : number of bytes NOT cleared 19 */ 20WEAK(__clear_user) 21 stm.w (lr), [sp-] 22 stm.w (r1), [sp-] 23 mov r2, #0 24 csub.a r1, #4 25 bsl 2f 26 and.a ip, r0, #3 27 beq 1f 28 csub.a ip, #2 29 strusr r2, r0, 1 30 strusr r2, r0, 1, el 31 strusr r2, r0, 1, sl 32 rsub ip, ip, #4 33 sub r1, r1, ip @ 7 6 5 4 3 2 1 341: sub.a r1, r1, #8 @ -1 -2 -3 -4 -5 -6 -7 35 strusr r2, r0, 4, ns, rept=2 36 bns 1b 37 add.a r1, r1, #4 @ 3 2 1 0 -1 -2 -3 38 strusr r2, r0, 4, ns 392: cand.a r1, #2 @ 1x 1x 0x 0x 1x 1x 0x 40 strusr r2, r0, 1, ne, rept=2 41 cand.a r1, #1 @ x1 x0 x1 x0 x1 x0 x1 42 beq 3f 43USER( stb.u r2, [r0]) 443: mov r0, #0 45 ldm.w (r1), [sp]+ 46 ldm.w (pc), [sp]+ 47ENDPROC(__clear_user) 48 49 .pushsection .fixup,"ax" 50 .align 0 519001: ldm.w (r0), [sp]+ 52 ldm.w (pc), [sp]+ 53 .popsection 54 55