1/* SPDX-License-Identifier: GPL-2.0 */ 2/* 3 * Copyright (C) 2020-2022 Loongson Technology Corporation Limited 4 */ 5 6#include <linux/export.h> 7#include <asm/alternative-asm.h> 8#include <asm/asm.h> 9#include <asm/asmmacro.h> 10#include <asm/asm-extable.h> 11#include <asm/cpu.h> 12#include <asm/regdef.h> 13#include <asm/unwind_hints.h> 14 15SYM_FUNC_START(__clear_user) 16 /* 17 * Some CPUs support hardware unaligned access 18 */ 19 ALTERNATIVE "b __clear_user_generic", \ 20 "b __clear_user_fast", CPU_FEATURE_UAL 21SYM_FUNC_END(__clear_user) 22 23EXPORT_SYMBOL(__clear_user) 24 25/* 26 * unsigned long __clear_user_generic(void *addr, size_t size) 27 * 28 * a0: addr 29 * a1: size 30 */ 31SYM_FUNC_START(__clear_user_generic) 32 beqz a1, 2f 33 341: st.b zero, a0, 0 35 addi.d a0, a0, 1 36 addi.d a1, a1, -1 37 bgtz a1, 1b 38 392: move a0, a1 40 jr ra 41 42 _asm_extable 1b, 2b 43SYM_FUNC_END(__clear_user_generic) 44 45/* 46 * unsigned long __clear_user_fast(void *addr, unsigned long size) 47 * 48 * a0: addr 49 * a1: size 50 */ 51SYM_FUNC_START(__clear_user_fast) 52 sltui t0, a1, 9 53 bnez t0, .Lsmall 54 55 add.d a2, a0, a1 560: st.d zero, a0, 0 57 58 /* align up address */ 59 addi.d a0, a0, 8 60 bstrins.d a0, zero, 2, 0 61 62 addi.d a3, a2, -64 63 bgeu a0, a3, .Llt64 64 65 /* set 64 bytes at a time */ 66.Lloop64: 671: st.d zero, a0, 0 682: st.d zero, a0, 8 693: st.d zero, a0, 16 704: st.d zero, a0, 24 715: st.d zero, a0, 32 726: st.d zero, a0, 40 737: st.d zero, a0, 48 748: st.d zero, a0, 56 75 addi.d a0, a0, 64 76 bltu a0, a3, .Lloop64 77 78 /* set the remaining bytes */ 79.Llt64: 80 addi.d a3, a2, -32 81 bgeu a0, a3, .Llt32 829: st.d zero, a0, 0 8310: st.d zero, a0, 8 8411: st.d zero, a0, 16 8512: st.d zero, a0, 24 86 addi.d a0, a0, 32 87 88.Llt32: 89 addi.d a3, a2, -16 90 bgeu a0, a3, .Llt16 9113: st.d zero, a0, 0 9214: st.d zero, a0, 8 93 addi.d a0, a0, 16 94 95.Llt16: 96 addi.d a3, a2, -8 97 bgeu a0, a3, .Llt8 9815: st.d zero, a0, 0 99 addi.d a0, a0, 8 100 101.Llt8: 10216: st.d zero, a2, -8 103 104 /* return */ 105 move a0, zero 106 jr ra 107 108 .align 4 109.Lsmall: 110 pcaddi t0, 4 111 slli.d a2, a1, 4 112 add.d t0, t0, a2 113 jr t0 114 115 .align 4 116 move a0, zero 117 jr ra 118 119 .align 4 12017: st.b zero, a0, 0 121 move a0, zero 122 jr ra 123 124 .align 4 12518: st.h zero, a0, 0 126 move a0, zero 127 jr ra 128 129 .align 4 13019: st.h zero, a0, 0 13120: st.b zero, a0, 2 132 move a0, zero 133 jr ra 134 135 .align 4 13621: st.w zero, a0, 0 137 move a0, zero 138 jr ra 139 140 .align 4 14122: st.w zero, a0, 0 14223: st.b zero, a0, 4 143 move a0, zero 144 jr ra 145 146 .align 4 14724: st.w zero, a0, 0 14825: st.h zero, a0, 4 149 move a0, zero 150 jr ra 151 152 .align 4 15326: st.w zero, a0, 0 15427: st.w zero, a0, 3 155 move a0, zero 156 jr ra 157 158 .align 4 15928: st.d zero, a0, 0 160 move a0, zero 161 jr ra 162 163 /* fixup and ex_table */ 164.Llarge_fixup: 165 sub.d a1, a2, a0 166 167.Lsmall_fixup: 16829: st.b zero, a0, 0 169 addi.d a0, a0, 1 170 addi.d a1, a1, -1 171 bgt a1, zero, 29b 172 173.Lexit: 174 move a0, a1 175 jr ra 176 177 _asm_extable 0b, .Lsmall_fixup 178 _asm_extable 1b, .Llarge_fixup 179 _asm_extable 2b, .Llarge_fixup 180 _asm_extable 3b, .Llarge_fixup 181 _asm_extable 4b, .Llarge_fixup 182 _asm_extable 5b, .Llarge_fixup 183 _asm_extable 6b, .Llarge_fixup 184 _asm_extable 7b, .Llarge_fixup 185 _asm_extable 8b, .Llarge_fixup 186 _asm_extable 9b, .Llarge_fixup 187 _asm_extable 10b, .Llarge_fixup 188 _asm_extable 11b, .Llarge_fixup 189 _asm_extable 12b, .Llarge_fixup 190 _asm_extable 13b, .Llarge_fixup 191 _asm_extable 14b, .Llarge_fixup 192 _asm_extable 15b, .Llarge_fixup 193 _asm_extable 16b, .Llarge_fixup 194 _asm_extable 17b, .Lexit 195 _asm_extable 18b, .Lsmall_fixup 196 _asm_extable 19b, .Lsmall_fixup 197 _asm_extable 20b, .Lsmall_fixup 198 _asm_extable 21b, .Lsmall_fixup 199 _asm_extable 22b, .Lsmall_fixup 200 _asm_extable 23b, .Lsmall_fixup 201 _asm_extable 24b, .Lsmall_fixup 202 _asm_extable 25b, .Lsmall_fixup 203 _asm_extable 26b, .Lsmall_fixup 204 _asm_extable 27b, .Lsmall_fixup 205 _asm_extable 28b, .Lsmall_fixup 206 _asm_extable 29b, .Lexit 207SYM_FUNC_END(__clear_user_fast) 208 209STACK_FRAME_NON_STANDARD __clear_user_fast 210