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#ifdef CONFIG_32BIT 17 b __clear_user_generic 18#else 19 /* 20 * Some CPUs support hardware unaligned access 21 */ 22 ALTERNATIVE "b __clear_user_generic", \ 23 "b __clear_user_fast", CPU_FEATURE_UAL 24#endif 25SYM_FUNC_END(__clear_user) 26 27EXPORT_SYMBOL(__clear_user) 28 29/* 30 * unsigned long __clear_user_generic(void *addr, size_t size) 31 * 32 * a0: addr 33 * a1: size 34 */ 35SYM_FUNC_START(__clear_user_generic) 36 beqz a1, 2f 37 381: st.b zero, a0, 0 39 PTR_ADDI a0, a0, 1 40 PTR_ADDI a1, a1, -1 41 bgtz a1, 1b 42 432: move a0, a1 44 jr ra 45 46 _asm_extable 1b, 2b 47SYM_FUNC_END(__clear_user_generic) 48 49#ifdef CONFIG_64BIT 50/* 51 * unsigned long __clear_user_fast(void *addr, unsigned long size) 52 * 53 * a0: addr 54 * a1: size 55 */ 56SYM_FUNC_START(__clear_user_fast) 57 sltui t0, a1, 9 58 bnez t0, .Lsmall 59 60 add.d a2, a0, a1 610: st.d zero, a0, 0 62 63 /* align up address */ 64 addi.d a0, a0, 8 65 bstrins.d a0, zero, 2, 0 66 67 addi.d a3, a2, -64 68 bgeu a0, a3, .Llt64 69 70 /* set 64 bytes at a time */ 71.Lloop64: 721: st.d zero, a0, 0 732: st.d zero, a0, 8 743: st.d zero, a0, 16 754: st.d zero, a0, 24 765: st.d zero, a0, 32 776: st.d zero, a0, 40 787: st.d zero, a0, 48 798: st.d zero, a0, 56 80 addi.d a0, a0, 64 81 bltu a0, a3, .Lloop64 82 83 /* set the remaining bytes */ 84.Llt64: 85 addi.d a3, a2, -32 86 bgeu a0, a3, .Llt32 879: st.d zero, a0, 0 8810: st.d zero, a0, 8 8911: st.d zero, a0, 16 9012: st.d zero, a0, 24 91 addi.d a0, a0, 32 92 93.Llt32: 94 addi.d a3, a2, -16 95 bgeu a0, a3, .Llt16 9613: st.d zero, a0, 0 9714: st.d zero, a0, 8 98 addi.d a0, a0, 16 99 100.Llt16: 101 addi.d a3, a2, -8 102 bgeu a0, a3, .Llt8 10315: st.d zero, a0, 0 104 addi.d a0, a0, 8 105 106.Llt8: 10716: st.d zero, a2, -8 108 109 /* return */ 110 move a0, zero 111 jr ra 112 113 .align 4 114.Lsmall: 115 pcaddi t0, 4 116 slli.d a2, a1, 4 117 add.d t0, t0, a2 118 jr t0 119 120 .align 4 121 move a0, zero 122 jr ra 123 124 .align 4 12517: st.b zero, a0, 0 126 move a0, zero 127 jr ra 128 129 .align 4 13018: st.h zero, a0, 0 131 move a0, zero 132 jr ra 133 134 .align 4 13519: st.h zero, a0, 0 13620: st.b zero, a0, 2 137 move a0, zero 138 jr ra 139 140 .align 4 14121: st.w zero, a0, 0 142 move a0, zero 143 jr ra 144 145 .align 4 14622: st.w zero, a0, 0 14723: st.b zero, a0, 4 148 move a0, zero 149 jr ra 150 151 .align 4 15224: st.w zero, a0, 0 15325: st.h zero, a0, 4 154 move a0, zero 155 jr ra 156 157 .align 4 15826: st.w zero, a0, 0 15927: st.w zero, a0, 3 160 move a0, zero 161 jr ra 162 163 .align 4 16428: st.d zero, a0, 0 165 move a0, zero 166 jr ra 167 168 /* fixup and ex_table */ 169.Llarge_fixup: 170 sub.d a1, a2, a0 171 172.Lsmall_fixup: 17329: st.b zero, a0, 0 174 addi.d a0, a0, 1 175 addi.d a1, a1, -1 176 bgt a1, zero, 29b 177 178.Lexit: 179 move a0, a1 180 jr ra 181 182 _asm_extable 0b, .Lsmall_fixup 183 _asm_extable 1b, .Llarge_fixup 184 _asm_extable 2b, .Llarge_fixup 185 _asm_extable 3b, .Llarge_fixup 186 _asm_extable 4b, .Llarge_fixup 187 _asm_extable 5b, .Llarge_fixup 188 _asm_extable 6b, .Llarge_fixup 189 _asm_extable 7b, .Llarge_fixup 190 _asm_extable 8b, .Llarge_fixup 191 _asm_extable 9b, .Llarge_fixup 192 _asm_extable 10b, .Llarge_fixup 193 _asm_extable 11b, .Llarge_fixup 194 _asm_extable 12b, .Llarge_fixup 195 _asm_extable 13b, .Llarge_fixup 196 _asm_extable 14b, .Llarge_fixup 197 _asm_extable 15b, .Llarge_fixup 198 _asm_extable 16b, .Llarge_fixup 199 _asm_extable 17b, .Lexit 200 _asm_extable 18b, .Lsmall_fixup 201 _asm_extable 19b, .Lsmall_fixup 202 _asm_extable 20b, .Lsmall_fixup 203 _asm_extable 21b, .Lsmall_fixup 204 _asm_extable 22b, .Lsmall_fixup 205 _asm_extable 23b, .Lsmall_fixup 206 _asm_extable 24b, .Lsmall_fixup 207 _asm_extable 25b, .Lsmall_fixup 208 _asm_extable 26b, .Lsmall_fixup 209 _asm_extable 27b, .Lsmall_fixup 210 _asm_extable 28b, .Lsmall_fixup 211 _asm_extable 29b, .Lexit 212SYM_FUNC_END(__clear_user_fast) 213 214STACK_FRAME_NON_STANDARD __clear_user_fast 215#endif 216