1#include <linux/linkage.h> 2#include <linux/export.h> 3#include <asm/asm.h> 4#include <asm/asm-extable.h> 5#include <asm/csr.h> 6#include <asm/hwcap.h> 7#include <asm/alternative-macros.h> 8 9 .macro fixup op reg addr lbl 10100: 11 \op \reg, \addr 12 _asm_extable 100b, \lbl 13 .endm 14 15SYM_FUNC_START(__asm_copy_to_user) 16#ifdef CONFIG_RISCV_ISA_V 17 ALTERNATIVE("j fallback_scalar_usercopy", "nop", 0, RISCV_ISA_EXT_v, CONFIG_RISCV_ISA_V) 18 REG_L t0, riscv_v_usercopy_threshold 19 bltu a2, t0, fallback_scalar_usercopy 20 tail enter_vector_usercopy 21#endif 22SYM_FUNC_START(fallback_scalar_usercopy) 23 24 /* Enable access to user memory */ 25 li t6, SR_SUM 26 csrs CSR_STATUS, t6 27 28 /* 29 * Save the terminal address which will be used to compute the number 30 * of bytes copied in case of a fixup exception. 31 */ 32 add t5, a0, a2 33 34 /* 35 * Register allocation for code below: 36 * a0 - start of uncopied dst 37 * a1 - start of uncopied src 38 * a2 - size 39 * t0 - end of uncopied dst 40 */ 41 add t0, a0, a2 42 43 /* 44 * Use byte copy only if too small. 45 * SZREG holds 4 for RV32 and 8 for RV64 46 */ 47 li a3, 9*SZREG /* size must be larger than size in word_copy */ 48 bltu a2, a3, .Lbyte_copy_tail 49 50 /* 51 * Copy first bytes until dst is aligned to word boundary. 52 * a0 - start of dst 53 * t1 - start of aligned dst 54 */ 55 addi t1, a0, SZREG-1 56 andi t1, t1, ~(SZREG-1) 57 /* dst is already aligned, skip */ 58 beq a0, t1, .Lskip_align_dst 591: 60 /* a5 - one byte for copying data */ 61 fixup lb a5, 0(a1), 10f 62 addi a1, a1, 1 /* src */ 63 fixup sb a5, 0(a0), 10f 64 addi a0, a0, 1 /* dst */ 65 bltu a0, t1, 1b /* t1 - start of aligned dst */ 66 67.Lskip_align_dst: 68 /* 69 * Now dst is aligned. 70 * Use shift-copy if src is misaligned. 71 * Use word-copy if both src and dst are aligned because 72 * can not use shift-copy which do not require shifting 73 */ 74 /* a1 - start of src */ 75 andi a3, a1, SZREG-1 76 bnez a3, .Lshift_copy 77 78.Lword_copy: 79 /* 80 * Both src and dst are aligned, unrolled word copy 81 * 82 * a0 - start of aligned dst 83 * a1 - start of aligned src 84 * t0 - end of aligned dst 85 */ 86 addi t0, t0, -(8*SZREG) /* not to over run */ 872: 88 fixup REG_L a4, 0(a1), 10f 89 fixup REG_L a5, SZREG(a1), 10f 90 fixup REG_L a6, 2*SZREG(a1), 10f 91 fixup REG_L a7, 3*SZREG(a1), 10f 92 fixup REG_L t1, 4*SZREG(a1), 10f 93 fixup REG_L t2, 5*SZREG(a1), 10f 94 fixup REG_L t3, 6*SZREG(a1), 10f 95 fixup REG_L t4, 7*SZREG(a1), 10f 96 fixup REG_S a4, 0(a0), 10f 97 fixup REG_S a5, SZREG(a0), 10f 98 fixup REG_S a6, 2*SZREG(a0), 10f 99 fixup REG_S a7, 3*SZREG(a0), 10f 100 fixup REG_S t1, 4*SZREG(a0), 10f 101 fixup REG_S t2, 5*SZREG(a0), 10f 102 fixup REG_S t3, 6*SZREG(a0), 10f 103 fixup REG_S t4, 7*SZREG(a0), 10f 104 addi a0, a0, 8*SZREG 105 addi a1, a1, 8*SZREG 106 bltu a0, t0, 2b 107 108 addi t0, t0, 8*SZREG /* revert to original value */ 109 j .Lbyte_copy_tail 110 111.Lshift_copy: 112 113 /* 114 * Word copy with shifting. 115 * For misaligned copy we still perform aligned word copy, but 116 * we need to use the value fetched from the previous iteration and 117 * do some shifts. 118 * This is safe because reading is less than a word size. 119 * 120 * a0 - start of aligned dst 121 * a1 - start of src 122 * a3 - a1 & mask:(SZREG-1) 123 * t0 - end of uncopied dst 124 * t1 - end of aligned dst 125 */ 126 /* calculating aligned word boundary for dst */ 127 andi t1, t0, ~(SZREG-1) 128 /* Converting unaligned src to aligned src */ 129 andi a1, a1, ~(SZREG-1) 130 131 /* 132 * Calculate shifts 133 * t3 - prev shift 134 * t4 - current shift 135 */ 136 slli t3, a3, 3 /* converting bytes in a3 to bits */ 137 li a5, SZREG*8 138 sub t4, a5, t3 139 140 /* Load the first word to combine with second word */ 141 fixup REG_L a5, 0(a1), 10f 142 1433: 144 /* Main shifting copy 145 * 146 * a0 - start of aligned dst 147 * a1 - start of aligned src 148 * t1 - end of aligned dst 149 */ 150 151 /* At least one iteration will be executed */ 152 srl a4, a5, t3 153 fixup REG_L a5, SZREG(a1), 10f 154 addi a1, a1, SZREG 155 sll a2, a5, t4 156 or a2, a2, a4 157 fixup REG_S a2, 0(a0), 10f 158 addi a0, a0, SZREG 159 bltu a0, t1, 3b 160 161 /* Revert src to original unaligned value */ 162 add a1, a1, a3 163 164.Lbyte_copy_tail: 165 /* 166 * Byte copy anything left. 167 * 168 * a0 - start of remaining dst 169 * a1 - start of remaining src 170 * t0 - end of remaining dst 171 */ 172 bgeu a0, t0, .Lout_copy_user /* check if end of copy */ 1734: 174 fixup lb a5, 0(a1), 10f 175 addi a1, a1, 1 /* src */ 176 fixup sb a5, 0(a0), 10f 177 addi a0, a0, 1 /* dst */ 178 bltu a0, t0, 4b /* t0 - end of dst */ 179 180.Lout_copy_user: 181 /* Disable access to user memory */ 182 csrc CSR_STATUS, t6 183 li a0, 0 184 ret 185 186 /* Exception fixup code */ 18710: 188 /* Disable access to user memory */ 189 csrc CSR_STATUS, t6 190 sub a0, t5, a0 191 ret 192SYM_FUNC_END(__asm_copy_to_user) 193SYM_FUNC_END(fallback_scalar_usercopy) 194EXPORT_SYMBOL(__asm_copy_to_user) 195SYM_FUNC_ALIAS(__asm_copy_from_user, __asm_copy_to_user) 196EXPORT_SYMBOL(__asm_copy_from_user) 197 198 199SYM_FUNC_START(__clear_user) 200 201 /* Enable access to user memory */ 202 li t6, SR_SUM 203 csrs CSR_STATUS, t6 204 205 add a3, a0, a1 206 addi t0, a0, SZREG-1 207 andi t1, a3, ~(SZREG-1) 208 andi t0, t0, ~(SZREG-1) 209 /* 210 * a3: terminal address of target region 211 * t0: lowest doubleword-aligned address in target region 212 * t1: highest doubleword-aligned address in target region 213 */ 214 bgeu t0, t1, 2f 215 bltu a0, t0, 4f 2161: 217 fixup REG_S, zero, (a0), 11f 218 addi a0, a0, SZREG 219 bltu a0, t1, 1b 2202: 221 bltu a0, a3, 5f 222 2233: 224 /* Disable access to user memory */ 225 csrc CSR_STATUS, t6 226 li a0, 0 227 ret 2284: /* Edge case: unalignment */ 229 fixup sb, zero, (a0), 11f 230 addi a0, a0, 1 231 bltu a0, t0, 4b 232 j 1b 2335: /* Edge case: remainder */ 234 fixup sb, zero, (a0), 11f 235 addi a0, a0, 1 236 bltu a0, a3, 5b 237 j 3b 238 239 /* Exception fixup code */ 24011: 241 /* Disable access to user memory */ 242 csrc CSR_STATUS, t6 243 sub a0, a3, a0 244 ret 245SYM_FUNC_END(__clear_user) 246EXPORT_SYMBOL(__clear_user) 247