1 /* 2 * Standard user space access functions based on mvcp/mvcs and doing 3 * interesting things in the secondary space mode. 4 * 5 * Copyright IBM Corp. 2006,2014 6 * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com), 7 * Gerald Schaefer (gerald.schaefer@de.ibm.com) 8 */ 9 10 #include <linux/jump_label.h> 11 #include <linux/uaccess.h> 12 #include <linux/export.h> 13 #include <linux/errno.h> 14 #include <linux/mm.h> 15 #include <asm/mmu_context.h> 16 #include <asm/facility.h> 17 18 static struct static_key have_mvcos = STATIC_KEY_INIT_FALSE; 19 20 static inline unsigned long copy_from_user_mvcos(void *x, const void __user *ptr, 21 unsigned long size) 22 { 23 register unsigned long reg0 asm("0") = 0x81UL; 24 unsigned long tmp1, tmp2; 25 26 tmp1 = -4096UL; 27 asm volatile( 28 "0: .insn ss,0xc80000000000,0(%0,%2),0(%1),0\n" 29 "9: jz 7f\n" 30 "1: algr %0,%3\n" 31 " slgr %1,%3\n" 32 " slgr %2,%3\n" 33 " j 0b\n" 34 "2: la %4,4095(%1)\n"/* %4 = ptr + 4095 */ 35 " nr %4,%3\n" /* %4 = (ptr + 4095) & -4096 */ 36 " slgr %4,%1\n" 37 " clgr %0,%4\n" /* copy crosses next page boundary? */ 38 " jnh 4f\n" 39 "3: .insn ss,0xc80000000000,0(%4,%2),0(%1),0\n" 40 "10:slgr %0,%4\n" 41 " algr %2,%4\n" 42 "4: lghi %4,-1\n" 43 " algr %4,%0\n" /* copy remaining size, subtract 1 */ 44 " bras %3,6f\n" /* memset loop */ 45 " xc 0(1,%2),0(%2)\n" 46 "5: xc 0(256,%2),0(%2)\n" 47 " la %2,256(%2)\n" 48 "6: aghi %4,-256\n" 49 " jnm 5b\n" 50 " ex %4,0(%3)\n" 51 " j 8f\n" 52 "7:slgr %0,%0\n" 53 "8:\n" 54 EX_TABLE(0b,2b) EX_TABLE(3b,4b) EX_TABLE(9b,2b) EX_TABLE(10b,4b) 55 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2) 56 : "d" (reg0) : "cc", "memory"); 57 return size; 58 } 59 60 static inline unsigned long copy_from_user_mvcp(void *x, const void __user *ptr, 61 unsigned long size) 62 { 63 unsigned long tmp1, tmp2; 64 65 load_kernel_asce(); 66 tmp1 = -256UL; 67 asm volatile( 68 " sacf 0\n" 69 "0: mvcp 0(%0,%2),0(%1),%3\n" 70 "10:jz 8f\n" 71 "1: algr %0,%3\n" 72 " la %1,256(%1)\n" 73 " la %2,256(%2)\n" 74 "2: mvcp 0(%0,%2),0(%1),%3\n" 75 "11:jnz 1b\n" 76 " j 8f\n" 77 "3: la %4,255(%1)\n" /* %4 = ptr + 255 */ 78 " lghi %3,-4096\n" 79 " nr %4,%3\n" /* %4 = (ptr + 255) & -4096 */ 80 " slgr %4,%1\n" 81 " clgr %0,%4\n" /* copy crosses next page boundary? */ 82 " jnh 5f\n" 83 "4: mvcp 0(%4,%2),0(%1),%3\n" 84 "12:slgr %0,%4\n" 85 " algr %2,%4\n" 86 "5: lghi %4,-1\n" 87 " algr %4,%0\n" /* copy remaining size, subtract 1 */ 88 " bras %3,7f\n" /* memset loop */ 89 " xc 0(1,%2),0(%2)\n" 90 "6: xc 0(256,%2),0(%2)\n" 91 " la %2,256(%2)\n" 92 "7: aghi %4,-256\n" 93 " jnm 6b\n" 94 " ex %4,0(%3)\n" 95 " j 9f\n" 96 "8:slgr %0,%0\n" 97 "9: sacf 768\n" 98 EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,5b) 99 EX_TABLE(10b,3b) EX_TABLE(11b,3b) EX_TABLE(12b,5b) 100 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2) 101 : : "cc", "memory"); 102 return size; 103 } 104 105 unsigned long __copy_from_user(void *to, const void __user *from, unsigned long n) 106 { 107 if (static_key_false(&have_mvcos)) 108 return copy_from_user_mvcos(to, from, n); 109 return copy_from_user_mvcp(to, from, n); 110 } 111 EXPORT_SYMBOL(__copy_from_user); 112 113 static inline unsigned long copy_to_user_mvcos(void __user *ptr, const void *x, 114 unsigned long size) 115 { 116 register unsigned long reg0 asm("0") = 0x810000UL; 117 unsigned long tmp1, tmp2; 118 119 tmp1 = -4096UL; 120 asm volatile( 121 "0: .insn ss,0xc80000000000,0(%0,%1),0(%2),0\n" 122 "6: jz 4f\n" 123 "1: algr %0,%3\n" 124 " slgr %1,%3\n" 125 " slgr %2,%3\n" 126 " j 0b\n" 127 "2: la %4,4095(%1)\n"/* %4 = ptr + 4095 */ 128 " nr %4,%3\n" /* %4 = (ptr + 4095) & -4096 */ 129 " slgr %4,%1\n" 130 " clgr %0,%4\n" /* copy crosses next page boundary? */ 131 " jnh 5f\n" 132 "3: .insn ss,0xc80000000000,0(%4,%1),0(%2),0\n" 133 "7: slgr %0,%4\n" 134 " j 5f\n" 135 "4: slgr %0,%0\n" 136 "5:\n" 137 EX_TABLE(0b,2b) EX_TABLE(3b,5b) EX_TABLE(6b,2b) EX_TABLE(7b,5b) 138 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2) 139 : "d" (reg0) : "cc", "memory"); 140 return size; 141 } 142 143 static inline unsigned long copy_to_user_mvcs(void __user *ptr, const void *x, 144 unsigned long size) 145 { 146 unsigned long tmp1, tmp2; 147 148 load_kernel_asce(); 149 tmp1 = -256UL; 150 asm volatile( 151 " sacf 0\n" 152 "0: mvcs 0(%0,%1),0(%2),%3\n" 153 "7: jz 5f\n" 154 "1: algr %0,%3\n" 155 " la %1,256(%1)\n" 156 " la %2,256(%2)\n" 157 "2: mvcs 0(%0,%1),0(%2),%3\n" 158 "8: jnz 1b\n" 159 " j 5f\n" 160 "3: la %4,255(%1)\n" /* %4 = ptr + 255 */ 161 " lghi %3,-4096\n" 162 " nr %4,%3\n" /* %4 = (ptr + 255) & -4096 */ 163 " slgr %4,%1\n" 164 " clgr %0,%4\n" /* copy crosses next page boundary? */ 165 " jnh 6f\n" 166 "4: mvcs 0(%4,%1),0(%2),%3\n" 167 "9: slgr %0,%4\n" 168 " j 6f\n" 169 "5: slgr %0,%0\n" 170 "6: sacf 768\n" 171 EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,6b) 172 EX_TABLE(7b,3b) EX_TABLE(8b,3b) EX_TABLE(9b,6b) 173 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2) 174 : : "cc", "memory"); 175 return size; 176 } 177 178 unsigned long __copy_to_user(void __user *to, const void *from, unsigned long n) 179 { 180 if (static_key_false(&have_mvcos)) 181 return copy_to_user_mvcos(to, from, n); 182 return copy_to_user_mvcs(to, from, n); 183 } 184 EXPORT_SYMBOL(__copy_to_user); 185 186 static inline unsigned long copy_in_user_mvcos(void __user *to, const void __user *from, 187 unsigned long size) 188 { 189 register unsigned long reg0 asm("0") = 0x810081UL; 190 unsigned long tmp1, tmp2; 191 192 tmp1 = -4096UL; 193 /* FIXME: copy with reduced length. */ 194 asm volatile( 195 "0: .insn ss,0xc80000000000,0(%0,%1),0(%2),0\n" 196 " jz 2f\n" 197 "1: algr %0,%3\n" 198 " slgr %1,%3\n" 199 " slgr %2,%3\n" 200 " j 0b\n" 201 "2:slgr %0,%0\n" 202 "3: \n" 203 EX_TABLE(0b,3b) 204 : "+a" (size), "+a" (to), "+a" (from), "+a" (tmp1), "=a" (tmp2) 205 : "d" (reg0) : "cc", "memory"); 206 return size; 207 } 208 209 static inline unsigned long copy_in_user_mvc(void __user *to, const void __user *from, 210 unsigned long size) 211 { 212 unsigned long tmp1; 213 214 load_kernel_asce(); 215 asm volatile( 216 " sacf 256\n" 217 " aghi %0,-1\n" 218 " jo 5f\n" 219 " bras %3,3f\n" 220 "0: aghi %0,257\n" 221 "1: mvc 0(1,%1),0(%2)\n" 222 " la %1,1(%1)\n" 223 " la %2,1(%2)\n" 224 " aghi %0,-1\n" 225 " jnz 1b\n" 226 " j 5f\n" 227 "2: mvc 0(256,%1),0(%2)\n" 228 " la %1,256(%1)\n" 229 " la %2,256(%2)\n" 230 "3: aghi %0,-256\n" 231 " jnm 2b\n" 232 "4: ex %0,1b-0b(%3)\n" 233 "5: slgr %0,%0\n" 234 "6: sacf 768\n" 235 EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b) 236 : "+a" (size), "+a" (to), "+a" (from), "=a" (tmp1) 237 : : "cc", "memory"); 238 return size; 239 } 240 241 unsigned long __copy_in_user(void __user *to, const void __user *from, unsigned long n) 242 { 243 if (static_key_false(&have_mvcos)) 244 return copy_in_user_mvcos(to, from, n); 245 return copy_in_user_mvc(to, from, n); 246 } 247 EXPORT_SYMBOL(__copy_in_user); 248 249 static inline unsigned long clear_user_mvcos(void __user *to, unsigned long size) 250 { 251 register unsigned long reg0 asm("0") = 0x810000UL; 252 unsigned long tmp1, tmp2; 253 254 tmp1 = -4096UL; 255 asm volatile( 256 "0: .insn ss,0xc80000000000,0(%0,%1),0(%4),0\n" 257 " jz 4f\n" 258 "1: algr %0,%2\n" 259 " slgr %1,%2\n" 260 " j 0b\n" 261 "2: la %3,4095(%1)\n"/* %4 = to + 4095 */ 262 " nr %3,%2\n" /* %4 = (to + 4095) & -4096 */ 263 " slgr %3,%1\n" 264 " clgr %0,%3\n" /* copy crosses next page boundary? */ 265 " jnh 5f\n" 266 "3: .insn ss,0xc80000000000,0(%3,%1),0(%4),0\n" 267 " slgr %0,%3\n" 268 " j 5f\n" 269 "4:slgr %0,%0\n" 270 "5:\n" 271 EX_TABLE(0b,2b) EX_TABLE(3b,5b) 272 : "+a" (size), "+a" (to), "+a" (tmp1), "=a" (tmp2) 273 : "a" (empty_zero_page), "d" (reg0) : "cc", "memory"); 274 return size; 275 } 276 277 static inline unsigned long clear_user_xc(void __user *to, unsigned long size) 278 { 279 unsigned long tmp1, tmp2; 280 281 load_kernel_asce(); 282 asm volatile( 283 " sacf 256\n" 284 " aghi %0,-1\n" 285 " jo 5f\n" 286 " bras %3,3f\n" 287 " xc 0(1,%1),0(%1)\n" 288 "0: aghi %0,257\n" 289 " la %2,255(%1)\n" /* %2 = ptr + 255 */ 290 " srl %2,12\n" 291 " sll %2,12\n" /* %2 = (ptr + 255) & -4096 */ 292 " slgr %2,%1\n" 293 " clgr %0,%2\n" /* clear crosses next page boundary? */ 294 " jnh 5f\n" 295 " aghi %2,-1\n" 296 "1: ex %2,0(%3)\n" 297 " aghi %2,1\n" 298 " slgr %0,%2\n" 299 " j 5f\n" 300 "2: xc 0(256,%1),0(%1)\n" 301 " la %1,256(%1)\n" 302 "3: aghi %0,-256\n" 303 " jnm 2b\n" 304 "4: ex %0,0(%3)\n" 305 "5: slgr %0,%0\n" 306 "6: sacf 768\n" 307 EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b) 308 : "+a" (size), "+a" (to), "=a" (tmp1), "=a" (tmp2) 309 : : "cc", "memory"); 310 return size; 311 } 312 313 unsigned long __clear_user(void __user *to, unsigned long size) 314 { 315 if (static_key_false(&have_mvcos)) 316 return clear_user_mvcos(to, size); 317 return clear_user_xc(to, size); 318 } 319 EXPORT_SYMBOL(__clear_user); 320 321 static inline unsigned long strnlen_user_srst(const char __user *src, 322 unsigned long size) 323 { 324 register unsigned long reg0 asm("0") = 0; 325 unsigned long tmp1, tmp2; 326 327 asm volatile( 328 " la %2,0(%1)\n" 329 " la %3,0(%0,%1)\n" 330 " slgr %0,%0\n" 331 " sacf 256\n" 332 "0: srst %3,%2\n" 333 " jo 0b\n" 334 " la %0,1(%3)\n" /* strnlen_user results includes \0 */ 335 " slgr %0,%1\n" 336 "1: sacf 768\n" 337 EX_TABLE(0b,1b) 338 : "+a" (size), "+a" (src), "=a" (tmp1), "=a" (tmp2) 339 : "d" (reg0) : "cc", "memory"); 340 return size; 341 } 342 343 unsigned long __strnlen_user(const char __user *src, unsigned long size) 344 { 345 if (unlikely(!size)) 346 return 0; 347 load_kernel_asce(); 348 return strnlen_user_srst(src, size); 349 } 350 EXPORT_SYMBOL(__strnlen_user); 351 352 long __strncpy_from_user(char *dst, const char __user *src, long size) 353 { 354 size_t done, len, offset, len_str; 355 356 if (unlikely(size <= 0)) 357 return 0; 358 done = 0; 359 do { 360 offset = (size_t)src & ~PAGE_MASK; 361 len = min(size - done, PAGE_SIZE - offset); 362 if (copy_from_user(dst, src, len)) 363 return -EFAULT; 364 len_str = strnlen(dst, len); 365 done += len_str; 366 src += len_str; 367 dst += len_str; 368 } while ((len_str == len) && (done < size)); 369 return done; 370 } 371 EXPORT_SYMBOL(__strncpy_from_user); 372 373 /* 374 * The "old" uaccess variant without mvcos can be enforced with the 375 * uaccess_primary kernel parameter. This is mainly for debugging purposes. 376 */ 377 static int uaccess_primary __initdata; 378 379 static int __init parse_uaccess_pt(char *__unused) 380 { 381 uaccess_primary = 1; 382 return 0; 383 } 384 early_param("uaccess_primary", parse_uaccess_pt); 385 386 static int __init uaccess_init(void) 387 { 388 if (!uaccess_primary && test_facility(27)) 389 static_key_slow_inc(&have_mvcos); 390 return 0; 391 } 392 early_initcall(uaccess_init); 393