1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Standard user space access functions based on mvcp/mvcs and doing 4 * interesting things in the secondary space mode. 5 * 6 * Copyright IBM Corp. 2006,2014 7 * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com), 8 * Gerald Schaefer (gerald.schaefer@de.ibm.com) 9 */ 10 11 #include <linux/jump_label.h> 12 #include <linux/uaccess.h> 13 #include <linux/export.h> 14 #include <linux/errno.h> 15 #include <linux/mm.h> 16 #include <asm/mmu_context.h> 17 #include <asm/facility.h> 18 19 #ifdef CONFIG_DEBUG_ENTRY 20 void debug_user_asce(int exit) 21 { 22 unsigned long cr1, cr7; 23 24 __ctl_store(cr1, 1, 1); 25 __ctl_store(cr7, 7, 7); 26 if (cr1 == S390_lowcore.kernel_asce && cr7 == S390_lowcore.user_asce) 27 return; 28 panic("incorrect ASCE on kernel %s\n" 29 "cr1: %016lx cr7: %016lx\n" 30 "kernel: %016llx user: %016llx\n", 31 exit ? "exit" : "entry", cr1, cr7, 32 S390_lowcore.kernel_asce, S390_lowcore.user_asce); 33 34 } 35 #endif /*CONFIG_DEBUG_ENTRY */ 36 37 #ifndef CONFIG_HAVE_MARCH_Z10_FEATURES 38 static DEFINE_STATIC_KEY_FALSE(have_mvcos); 39 40 static int __init uaccess_init(void) 41 { 42 if (test_facility(27)) 43 static_branch_enable(&have_mvcos); 44 return 0; 45 } 46 early_initcall(uaccess_init); 47 48 static inline int copy_with_mvcos(void) 49 { 50 if (static_branch_likely(&have_mvcos)) 51 return 1; 52 return 0; 53 } 54 #else 55 static inline int copy_with_mvcos(void) 56 { 57 return 1; 58 } 59 #endif 60 61 static inline unsigned long copy_from_user_mvcos(void *x, const void __user *ptr, 62 unsigned long size) 63 { 64 unsigned long tmp1, tmp2; 65 66 tmp1 = -4096UL; 67 asm volatile( 68 " lghi 0,%[spec]\n" 69 "0: .insn ss,0xc80000000000,0(%0,%2),0(%1),0\n" 70 "6: jz 4f\n" 71 "1: algr %0,%3\n" 72 " slgr %1,%3\n" 73 " slgr %2,%3\n" 74 " j 0b\n" 75 "2: la %4,4095(%1)\n"/* %4 = ptr + 4095 */ 76 " nr %4,%3\n" /* %4 = (ptr + 4095) & -4096 */ 77 " slgr %4,%1\n" 78 " clgr %0,%4\n" /* copy crosses next page boundary? */ 79 " jnh 5f\n" 80 "3: .insn ss,0xc80000000000,0(%4,%2),0(%1),0\n" 81 "7: slgr %0,%4\n" 82 " j 5f\n" 83 "4: slgr %0,%0\n" 84 "5:\n" 85 EX_TABLE(0b,2b) EX_TABLE(3b,5b) EX_TABLE(6b,2b) EX_TABLE(7b,5b) 86 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2) 87 : [spec] "K" (0x81UL) 88 : "cc", "memory", "0"); 89 return size; 90 } 91 92 static inline unsigned long copy_from_user_mvcp(void *x, const void __user *ptr, 93 unsigned long size) 94 { 95 unsigned long tmp1, tmp2; 96 97 tmp1 = -256UL; 98 asm volatile( 99 " sacf 0\n" 100 "0: mvcp 0(%0,%2),0(%1),%3\n" 101 "7: jz 5f\n" 102 "1: algr %0,%3\n" 103 " la %1,256(%1)\n" 104 " la %2,256(%2)\n" 105 "2: mvcp 0(%0,%2),0(%1),%3\n" 106 "8: jnz 1b\n" 107 " j 5f\n" 108 "3: la %4,255(%1)\n" /* %4 = ptr + 255 */ 109 " lghi %3,-4096\n" 110 " nr %4,%3\n" /* %4 = (ptr + 255) & -4096 */ 111 " slgr %4,%1\n" 112 " clgr %0,%4\n" /* copy crosses next page boundary? */ 113 " jnh 6f\n" 114 "4: mvcp 0(%4,%2),0(%1),%3\n" 115 "9: slgr %0,%4\n" 116 " j 6f\n" 117 "5: slgr %0,%0\n" 118 "6: sacf 768\n" 119 EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,6b) 120 EX_TABLE(7b,3b) EX_TABLE(8b,3b) EX_TABLE(9b,6b) 121 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2) 122 : : "cc", "memory"); 123 return size; 124 } 125 126 unsigned long raw_copy_from_user(void *to, const void __user *from, unsigned long n) 127 { 128 if (copy_with_mvcos()) 129 return copy_from_user_mvcos(to, from, n); 130 return copy_from_user_mvcp(to, from, n); 131 } 132 EXPORT_SYMBOL(raw_copy_from_user); 133 134 static inline unsigned long copy_to_user_mvcos(void __user *ptr, const void *x, 135 unsigned long size) 136 { 137 unsigned long tmp1, tmp2; 138 139 tmp1 = -4096UL; 140 asm volatile( 141 " llilh 0,%[spec]\n" 142 "0: .insn ss,0xc80000000000,0(%0,%1),0(%2),0\n" 143 "6: jz 4f\n" 144 "1: algr %0,%3\n" 145 " slgr %1,%3\n" 146 " slgr %2,%3\n" 147 " j 0b\n" 148 "2: la %4,4095(%1)\n"/* %4 = ptr + 4095 */ 149 " nr %4,%3\n" /* %4 = (ptr + 4095) & -4096 */ 150 " slgr %4,%1\n" 151 " clgr %0,%4\n" /* copy crosses next page boundary? */ 152 " jnh 5f\n" 153 "3: .insn ss,0xc80000000000,0(%4,%1),0(%2),0\n" 154 "7: slgr %0,%4\n" 155 " j 5f\n" 156 "4: slgr %0,%0\n" 157 "5:\n" 158 EX_TABLE(0b,2b) EX_TABLE(3b,5b) EX_TABLE(6b,2b) EX_TABLE(7b,5b) 159 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2) 160 : [spec] "K" (0x81UL) 161 : "cc", "memory", "0"); 162 return size; 163 } 164 165 static inline unsigned long copy_to_user_mvcs(void __user *ptr, const void *x, 166 unsigned long size) 167 { 168 unsigned long tmp1, tmp2; 169 170 tmp1 = -256UL; 171 asm volatile( 172 " sacf 0\n" 173 "0: mvcs 0(%0,%1),0(%2),%3\n" 174 "7: jz 5f\n" 175 "1: algr %0,%3\n" 176 " la %1,256(%1)\n" 177 " la %2,256(%2)\n" 178 "2: mvcs 0(%0,%1),0(%2),%3\n" 179 "8: jnz 1b\n" 180 " j 5f\n" 181 "3: la %4,255(%1)\n" /* %4 = ptr + 255 */ 182 " lghi %3,-4096\n" 183 " nr %4,%3\n" /* %4 = (ptr + 255) & -4096 */ 184 " slgr %4,%1\n" 185 " clgr %0,%4\n" /* copy crosses next page boundary? */ 186 " jnh 6f\n" 187 "4: mvcs 0(%4,%1),0(%2),%3\n" 188 "9: slgr %0,%4\n" 189 " j 6f\n" 190 "5: slgr %0,%0\n" 191 "6: sacf 768\n" 192 EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,6b) 193 EX_TABLE(7b,3b) EX_TABLE(8b,3b) EX_TABLE(9b,6b) 194 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2) 195 : : "cc", "memory"); 196 return size; 197 } 198 199 unsigned long raw_copy_to_user(void __user *to, const void *from, unsigned long n) 200 { 201 if (copy_with_mvcos()) 202 return copy_to_user_mvcos(to, from, n); 203 return copy_to_user_mvcs(to, from, n); 204 } 205 EXPORT_SYMBOL(raw_copy_to_user); 206 207 static inline unsigned long copy_in_user_mvcos(void __user *to, const void __user *from, 208 unsigned long size) 209 { 210 unsigned long tmp1, tmp2; 211 212 tmp1 = -4096UL; 213 /* FIXME: copy with reduced length. */ 214 asm volatile( 215 " lgr 0,%[spec]\n" 216 "0: .insn ss,0xc80000000000,0(%0,%1),0(%2),0\n" 217 " jz 2f\n" 218 "1: algr %0,%3\n" 219 " slgr %1,%3\n" 220 " slgr %2,%3\n" 221 " j 0b\n" 222 "2:slgr %0,%0\n" 223 "3: \n" 224 EX_TABLE(0b,3b) 225 : "+a" (size), "+a" (to), "+a" (from), "+a" (tmp1), "=a" (tmp2) 226 : [spec] "d" (0x810081UL) 227 : "cc", "memory", "0"); 228 return size; 229 } 230 231 static inline unsigned long copy_in_user_mvc(void __user *to, const void __user *from, 232 unsigned long size) 233 { 234 unsigned long tmp1; 235 236 asm volatile( 237 " sacf 256\n" 238 " aghi %0,-1\n" 239 " jo 5f\n" 240 " bras %3,3f\n" 241 "0: aghi %0,257\n" 242 "1: mvc 0(1,%1),0(%2)\n" 243 " la %1,1(%1)\n" 244 " la %2,1(%2)\n" 245 " aghi %0,-1\n" 246 " jnz 1b\n" 247 " j 5f\n" 248 "2: mvc 0(256,%1),0(%2)\n" 249 " la %1,256(%1)\n" 250 " la %2,256(%2)\n" 251 "3: aghi %0,-256\n" 252 " jnm 2b\n" 253 "4: ex %0,1b-0b(%3)\n" 254 "5: slgr %0,%0\n" 255 "6: sacf 768\n" 256 EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b) 257 : "+a" (size), "+a" (to), "+a" (from), "=a" (tmp1) 258 : : "cc", "memory"); 259 return size; 260 } 261 262 unsigned long raw_copy_in_user(void __user *to, const void __user *from, unsigned long n) 263 { 264 if (copy_with_mvcos()) 265 return copy_in_user_mvcos(to, from, n); 266 return copy_in_user_mvc(to, from, n); 267 } 268 EXPORT_SYMBOL(raw_copy_in_user); 269 270 static inline unsigned long clear_user_mvcos(void __user *to, unsigned long size) 271 { 272 unsigned long tmp1, tmp2; 273 274 tmp1 = -4096UL; 275 asm volatile( 276 " llilh 0,%[spec]\n" 277 "0: .insn ss,0xc80000000000,0(%0,%1),0(%4),0\n" 278 " jz 4f\n" 279 "1: algr %0,%2\n" 280 " slgr %1,%2\n" 281 " j 0b\n" 282 "2: la %3,4095(%1)\n"/* %4 = to + 4095 */ 283 " nr %3,%2\n" /* %4 = (to + 4095) & -4096 */ 284 " slgr %3,%1\n" 285 " clgr %0,%3\n" /* copy crosses next page boundary? */ 286 " jnh 5f\n" 287 "3: .insn ss,0xc80000000000,0(%3,%1),0(%4),0\n" 288 " slgr %0,%3\n" 289 " j 5f\n" 290 "4: slgr %0,%0\n" 291 "5:\n" 292 EX_TABLE(0b,2b) EX_TABLE(3b,5b) 293 : "+a" (size), "+a" (to), "+a" (tmp1), "=a" (tmp2) 294 : "a" (empty_zero_page), [spec] "K" (0x81UL) 295 : "cc", "memory", "0"); 296 return size; 297 } 298 299 static inline unsigned long clear_user_xc(void __user *to, unsigned long size) 300 { 301 unsigned long tmp1, tmp2; 302 303 asm volatile( 304 " sacf 256\n" 305 " aghi %0,-1\n" 306 " jo 5f\n" 307 " bras %3,3f\n" 308 " xc 0(1,%1),0(%1)\n" 309 "0: aghi %0,257\n" 310 " la %2,255(%1)\n" /* %2 = ptr + 255 */ 311 " srl %2,12\n" 312 " sll %2,12\n" /* %2 = (ptr + 255) & -4096 */ 313 " slgr %2,%1\n" 314 " clgr %0,%2\n" /* clear crosses next page boundary? */ 315 " jnh 5f\n" 316 " aghi %2,-1\n" 317 "1: ex %2,0(%3)\n" 318 " aghi %2,1\n" 319 " slgr %0,%2\n" 320 " j 5f\n" 321 "2: xc 0(256,%1),0(%1)\n" 322 " la %1,256(%1)\n" 323 "3: aghi %0,-256\n" 324 " jnm 2b\n" 325 "4: ex %0,0(%3)\n" 326 "5: slgr %0,%0\n" 327 "6: sacf 768\n" 328 EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b) 329 : "+a" (size), "+a" (to), "=a" (tmp1), "=a" (tmp2) 330 : : "cc", "memory"); 331 return size; 332 } 333 334 unsigned long __clear_user(void __user *to, unsigned long size) 335 { 336 if (copy_with_mvcos()) 337 return clear_user_mvcos(to, size); 338 return clear_user_xc(to, size); 339 } 340 EXPORT_SYMBOL(__clear_user); 341 342 static inline unsigned long strnlen_user_srst(const char __user *src, 343 unsigned long size) 344 { 345 unsigned long tmp1, tmp2; 346 347 asm volatile( 348 " lghi 0,0\n" 349 " la %2,0(%1)\n" 350 " la %3,0(%0,%1)\n" 351 " slgr %0,%0\n" 352 " sacf 256\n" 353 "0: srst %3,%2\n" 354 " jo 0b\n" 355 " la %0,1(%3)\n" /* strnlen_user results includes \0 */ 356 " slgr %0,%1\n" 357 "1: sacf 768\n" 358 EX_TABLE(0b,1b) 359 : "+a" (size), "+a" (src), "=a" (tmp1), "=a" (tmp2) 360 : 361 : "cc", "memory", "0"); 362 return size; 363 } 364 365 unsigned long __strnlen_user(const char __user *src, unsigned long size) 366 { 367 if (unlikely(!size)) 368 return 0; 369 return strnlen_user_srst(src, size); 370 } 371 EXPORT_SYMBOL(__strnlen_user); 372 373 long __strncpy_from_user(char *dst, const char __user *src, long size) 374 { 375 size_t done, len, offset, len_str; 376 377 if (unlikely(size <= 0)) 378 return 0; 379 done = 0; 380 do { 381 offset = (size_t)src & (L1_CACHE_BYTES - 1); 382 len = min(size - done, L1_CACHE_BYTES - offset); 383 if (copy_from_user(dst, src, len)) 384 return -EFAULT; 385 len_str = strnlen(dst, len); 386 done += len_str; 387 src += len_str; 388 dst += len_str; 389 } while ((len_str == len) && (done < size)); 390 return done; 391 } 392 EXPORT_SYMBOL(__strncpy_from_user); 393