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 register unsigned long reg0 asm("0") = 0x81UL; 65 unsigned long tmp1, tmp2; 66 67 tmp1 = -4096UL; 68 asm volatile( 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 : "d" (reg0) : "cc", "memory"); 88 return size; 89 } 90 91 static inline unsigned long copy_from_user_mvcp(void *x, const void __user *ptr, 92 unsigned long size) 93 { 94 unsigned long tmp1, tmp2; 95 96 tmp1 = -256UL; 97 asm volatile( 98 " sacf 0\n" 99 "0: mvcp 0(%0,%2),0(%1),%3\n" 100 "7: jz 5f\n" 101 "1: algr %0,%3\n" 102 " la %1,256(%1)\n" 103 " la %2,256(%2)\n" 104 "2: mvcp 0(%0,%2),0(%1),%3\n" 105 "8: jnz 1b\n" 106 " j 5f\n" 107 "3: la %4,255(%1)\n" /* %4 = ptr + 255 */ 108 " lghi %3,-4096\n" 109 " nr %4,%3\n" /* %4 = (ptr + 255) & -4096 */ 110 " slgr %4,%1\n" 111 " clgr %0,%4\n" /* copy crosses next page boundary? */ 112 " jnh 6f\n" 113 "4: mvcp 0(%4,%2),0(%1),%3\n" 114 "9: slgr %0,%4\n" 115 " j 6f\n" 116 "5: slgr %0,%0\n" 117 "6: sacf 768\n" 118 EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,6b) 119 EX_TABLE(7b,3b) EX_TABLE(8b,3b) EX_TABLE(9b,6b) 120 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2) 121 : : "cc", "memory"); 122 return size; 123 } 124 125 unsigned long raw_copy_from_user(void *to, const void __user *from, unsigned long n) 126 { 127 if (copy_with_mvcos()) 128 return copy_from_user_mvcos(to, from, n); 129 return copy_from_user_mvcp(to, from, n); 130 } 131 EXPORT_SYMBOL(raw_copy_from_user); 132 133 static inline unsigned long copy_to_user_mvcos(void __user *ptr, const void *x, 134 unsigned long size) 135 { 136 register unsigned long reg0 asm("0") = 0x810000UL; 137 unsigned long tmp1, tmp2; 138 139 tmp1 = -4096UL; 140 asm volatile( 141 "0: .insn ss,0xc80000000000,0(%0,%1),0(%2),0\n" 142 "6: jz 4f\n" 143 "1: algr %0,%3\n" 144 " slgr %1,%3\n" 145 " slgr %2,%3\n" 146 " j 0b\n" 147 "2: la %4,4095(%1)\n"/* %4 = ptr + 4095 */ 148 " nr %4,%3\n" /* %4 = (ptr + 4095) & -4096 */ 149 " slgr %4,%1\n" 150 " clgr %0,%4\n" /* copy crosses next page boundary? */ 151 " jnh 5f\n" 152 "3: .insn ss,0xc80000000000,0(%4,%1),0(%2),0\n" 153 "7: slgr %0,%4\n" 154 " j 5f\n" 155 "4: slgr %0,%0\n" 156 "5:\n" 157 EX_TABLE(0b,2b) EX_TABLE(3b,5b) EX_TABLE(6b,2b) EX_TABLE(7b,5b) 158 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2) 159 : "d" (reg0) : "cc", "memory"); 160 return size; 161 } 162 163 static inline unsigned long copy_to_user_mvcs(void __user *ptr, const void *x, 164 unsigned long size) 165 { 166 unsigned long tmp1, tmp2; 167 168 tmp1 = -256UL; 169 asm volatile( 170 " sacf 0\n" 171 "0: mvcs 0(%0,%1),0(%2),%3\n" 172 "7: jz 5f\n" 173 "1: algr %0,%3\n" 174 " la %1,256(%1)\n" 175 " la %2,256(%2)\n" 176 "2: mvcs 0(%0,%1),0(%2),%3\n" 177 "8: jnz 1b\n" 178 " j 5f\n" 179 "3: la %4,255(%1)\n" /* %4 = ptr + 255 */ 180 " lghi %3,-4096\n" 181 " nr %4,%3\n" /* %4 = (ptr + 255) & -4096 */ 182 " slgr %4,%1\n" 183 " clgr %0,%4\n" /* copy crosses next page boundary? */ 184 " jnh 6f\n" 185 "4: mvcs 0(%4,%1),0(%2),%3\n" 186 "9: slgr %0,%4\n" 187 " j 6f\n" 188 "5: slgr %0,%0\n" 189 "6: sacf 768\n" 190 EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,6b) 191 EX_TABLE(7b,3b) EX_TABLE(8b,3b) EX_TABLE(9b,6b) 192 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2) 193 : : "cc", "memory"); 194 return size; 195 } 196 197 unsigned long raw_copy_to_user(void __user *to, const void *from, unsigned long n) 198 { 199 if (copy_with_mvcos()) 200 return copy_to_user_mvcos(to, from, n); 201 return copy_to_user_mvcs(to, from, n); 202 } 203 EXPORT_SYMBOL(raw_copy_to_user); 204 205 static inline unsigned long copy_in_user_mvcos(void __user *to, const void __user *from, 206 unsigned long size) 207 { 208 register unsigned long reg0 asm("0") = 0x810081UL; 209 unsigned long tmp1, tmp2; 210 211 tmp1 = -4096UL; 212 /* FIXME: copy with reduced length. */ 213 asm volatile( 214 "0: .insn ss,0xc80000000000,0(%0,%1),0(%2),0\n" 215 " jz 2f\n" 216 "1: algr %0,%3\n" 217 " slgr %1,%3\n" 218 " slgr %2,%3\n" 219 " j 0b\n" 220 "2:slgr %0,%0\n" 221 "3: \n" 222 EX_TABLE(0b,3b) 223 : "+a" (size), "+a" (to), "+a" (from), "+a" (tmp1), "=a" (tmp2) 224 : "d" (reg0) : "cc", "memory"); 225 return size; 226 } 227 228 static inline unsigned long copy_in_user_mvc(void __user *to, const void __user *from, 229 unsigned long size) 230 { 231 unsigned long tmp1; 232 233 asm volatile( 234 " sacf 256\n" 235 " aghi %0,-1\n" 236 " jo 5f\n" 237 " bras %3,3f\n" 238 "0: aghi %0,257\n" 239 "1: mvc 0(1,%1),0(%2)\n" 240 " la %1,1(%1)\n" 241 " la %2,1(%2)\n" 242 " aghi %0,-1\n" 243 " jnz 1b\n" 244 " j 5f\n" 245 "2: mvc 0(256,%1),0(%2)\n" 246 " la %1,256(%1)\n" 247 " la %2,256(%2)\n" 248 "3: aghi %0,-256\n" 249 " jnm 2b\n" 250 "4: ex %0,1b-0b(%3)\n" 251 "5: slgr %0,%0\n" 252 "6: sacf 768\n" 253 EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b) 254 : "+a" (size), "+a" (to), "+a" (from), "=a" (tmp1) 255 : : "cc", "memory"); 256 return size; 257 } 258 259 unsigned long raw_copy_in_user(void __user *to, const void __user *from, unsigned long n) 260 { 261 if (copy_with_mvcos()) 262 return copy_in_user_mvcos(to, from, n); 263 return copy_in_user_mvc(to, from, n); 264 } 265 EXPORT_SYMBOL(raw_copy_in_user); 266 267 static inline unsigned long clear_user_mvcos(void __user *to, unsigned long size) 268 { 269 register unsigned long reg0 asm("0") = 0x810000UL; 270 unsigned long tmp1, tmp2; 271 272 tmp1 = -4096UL; 273 asm volatile( 274 "0: .insn ss,0xc80000000000,0(%0,%1),0(%4),0\n" 275 " jz 4f\n" 276 "1: algr %0,%2\n" 277 " slgr %1,%2\n" 278 " j 0b\n" 279 "2: la %3,4095(%1)\n"/* %4 = to + 4095 */ 280 " nr %3,%2\n" /* %4 = (to + 4095) & -4096 */ 281 " slgr %3,%1\n" 282 " clgr %0,%3\n" /* copy crosses next page boundary? */ 283 " jnh 5f\n" 284 "3: .insn ss,0xc80000000000,0(%3,%1),0(%4),0\n" 285 " slgr %0,%3\n" 286 " j 5f\n" 287 "4: slgr %0,%0\n" 288 "5:\n" 289 EX_TABLE(0b,2b) EX_TABLE(3b,5b) 290 : "+a" (size), "+a" (to), "+a" (tmp1), "=a" (tmp2) 291 : "a" (empty_zero_page), "d" (reg0) : "cc", "memory"); 292 return size; 293 } 294 295 static inline unsigned long clear_user_xc(void __user *to, unsigned long size) 296 { 297 unsigned long tmp1, tmp2; 298 299 asm volatile( 300 " sacf 256\n" 301 " aghi %0,-1\n" 302 " jo 5f\n" 303 " bras %3,3f\n" 304 " xc 0(1,%1),0(%1)\n" 305 "0: aghi %0,257\n" 306 " la %2,255(%1)\n" /* %2 = ptr + 255 */ 307 " srl %2,12\n" 308 " sll %2,12\n" /* %2 = (ptr + 255) & -4096 */ 309 " slgr %2,%1\n" 310 " clgr %0,%2\n" /* clear crosses next page boundary? */ 311 " jnh 5f\n" 312 " aghi %2,-1\n" 313 "1: ex %2,0(%3)\n" 314 " aghi %2,1\n" 315 " slgr %0,%2\n" 316 " j 5f\n" 317 "2: xc 0(256,%1),0(%1)\n" 318 " la %1,256(%1)\n" 319 "3: aghi %0,-256\n" 320 " jnm 2b\n" 321 "4: ex %0,0(%3)\n" 322 "5: slgr %0,%0\n" 323 "6: sacf 768\n" 324 EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b) 325 : "+a" (size), "+a" (to), "=a" (tmp1), "=a" (tmp2) 326 : : "cc", "memory"); 327 return size; 328 } 329 330 unsigned long __clear_user(void __user *to, unsigned long size) 331 { 332 if (copy_with_mvcos()) 333 return clear_user_mvcos(to, size); 334 return clear_user_xc(to, size); 335 } 336 EXPORT_SYMBOL(__clear_user); 337 338 static inline unsigned long strnlen_user_srst(const char __user *src, 339 unsigned long size) 340 { 341 register unsigned long reg0 asm("0") = 0; 342 unsigned long tmp1, tmp2; 343 344 asm volatile( 345 " la %2,0(%1)\n" 346 " la %3,0(%0,%1)\n" 347 " slgr %0,%0\n" 348 " sacf 256\n" 349 "0: srst %3,%2\n" 350 " jo 0b\n" 351 " la %0,1(%3)\n" /* strnlen_user results includes \0 */ 352 " slgr %0,%1\n" 353 "1: sacf 768\n" 354 EX_TABLE(0b,1b) 355 : "+a" (size), "+a" (src), "=a" (tmp1), "=a" (tmp2) 356 : "d" (reg0) : "cc", "memory"); 357 return size; 358 } 359 360 unsigned long __strnlen_user(const char __user *src, unsigned long size) 361 { 362 if (unlikely(!size)) 363 return 0; 364 return strnlen_user_srst(src, size); 365 } 366 EXPORT_SYMBOL(__strnlen_user); 367 368 long __strncpy_from_user(char *dst, const char __user *src, long size) 369 { 370 size_t done, len, offset, len_str; 371 372 if (unlikely(size <= 0)) 373 return 0; 374 done = 0; 375 do { 376 offset = (size_t)src & (L1_CACHE_BYTES - 1); 377 len = min(size - done, L1_CACHE_BYTES - offset); 378 if (copy_from_user(dst, src, len)) 379 return -EFAULT; 380 len_str = strnlen(dst, len); 381 done += len_str; 382 src += len_str; 383 dst += len_str; 384 } while ((len_str == len) && (done < size)); 385 return done; 386 } 387 EXPORT_SYMBOL(__strncpy_from_user); 388