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 DEFINE_STATIC_KEY_FALSE(have_mvcos); 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 check_object_size(to, n, false); 108 if (static_branch_likely(&have_mvcos)) 109 return copy_from_user_mvcos(to, from, n); 110 return copy_from_user_mvcp(to, from, n); 111 } 112 EXPORT_SYMBOL(__copy_from_user); 113 114 static inline unsigned long copy_to_user_mvcos(void __user *ptr, const void *x, 115 unsigned long size) 116 { 117 register unsigned long reg0 asm("0") = 0x810000UL; 118 unsigned long tmp1, tmp2; 119 120 tmp1 = -4096UL; 121 asm volatile( 122 "0: .insn ss,0xc80000000000,0(%0,%1),0(%2),0\n" 123 "6: jz 4f\n" 124 "1: algr %0,%3\n" 125 " slgr %1,%3\n" 126 " slgr %2,%3\n" 127 " j 0b\n" 128 "2: la %4,4095(%1)\n"/* %4 = ptr + 4095 */ 129 " nr %4,%3\n" /* %4 = (ptr + 4095) & -4096 */ 130 " slgr %4,%1\n" 131 " clgr %0,%4\n" /* copy crosses next page boundary? */ 132 " jnh 5f\n" 133 "3: .insn ss,0xc80000000000,0(%4,%1),0(%2),0\n" 134 "7: slgr %0,%4\n" 135 " j 5f\n" 136 "4: slgr %0,%0\n" 137 "5:\n" 138 EX_TABLE(0b,2b) EX_TABLE(3b,5b) EX_TABLE(6b,2b) EX_TABLE(7b,5b) 139 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2) 140 : "d" (reg0) : "cc", "memory"); 141 return size; 142 } 143 144 static inline unsigned long copy_to_user_mvcs(void __user *ptr, const void *x, 145 unsigned long size) 146 { 147 unsigned long tmp1, tmp2; 148 149 load_kernel_asce(); 150 tmp1 = -256UL; 151 asm volatile( 152 " sacf 0\n" 153 "0: mvcs 0(%0,%1),0(%2),%3\n" 154 "7: jz 5f\n" 155 "1: algr %0,%3\n" 156 " la %1,256(%1)\n" 157 " la %2,256(%2)\n" 158 "2: mvcs 0(%0,%1),0(%2),%3\n" 159 "8: jnz 1b\n" 160 " j 5f\n" 161 "3: la %4,255(%1)\n" /* %4 = ptr + 255 */ 162 " lghi %3,-4096\n" 163 " nr %4,%3\n" /* %4 = (ptr + 255) & -4096 */ 164 " slgr %4,%1\n" 165 " clgr %0,%4\n" /* copy crosses next page boundary? */ 166 " jnh 6f\n" 167 "4: mvcs 0(%4,%1),0(%2),%3\n" 168 "9: slgr %0,%4\n" 169 " j 6f\n" 170 "5: slgr %0,%0\n" 171 "6: sacf 768\n" 172 EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,6b) 173 EX_TABLE(7b,3b) EX_TABLE(8b,3b) EX_TABLE(9b,6b) 174 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2) 175 : : "cc", "memory"); 176 return size; 177 } 178 179 unsigned long __copy_to_user(void __user *to, const void *from, unsigned long n) 180 { 181 check_object_size(from, n, true); 182 if (static_branch_likely(&have_mvcos)) 183 return copy_to_user_mvcos(to, from, n); 184 return copy_to_user_mvcs(to, from, n); 185 } 186 EXPORT_SYMBOL(__copy_to_user); 187 188 static inline unsigned long copy_in_user_mvcos(void __user *to, const void __user *from, 189 unsigned long size) 190 { 191 register unsigned long reg0 asm("0") = 0x810081UL; 192 unsigned long tmp1, tmp2; 193 194 tmp1 = -4096UL; 195 /* FIXME: copy with reduced length. */ 196 asm volatile( 197 "0: .insn ss,0xc80000000000,0(%0,%1),0(%2),0\n" 198 " jz 2f\n" 199 "1: algr %0,%3\n" 200 " slgr %1,%3\n" 201 " slgr %2,%3\n" 202 " j 0b\n" 203 "2:slgr %0,%0\n" 204 "3: \n" 205 EX_TABLE(0b,3b) 206 : "+a" (size), "+a" (to), "+a" (from), "+a" (tmp1), "=a" (tmp2) 207 : "d" (reg0) : "cc", "memory"); 208 return size; 209 } 210 211 static inline unsigned long copy_in_user_mvc(void __user *to, const void __user *from, 212 unsigned long size) 213 { 214 unsigned long tmp1; 215 216 load_kernel_asce(); 217 asm volatile( 218 " sacf 256\n" 219 " aghi %0,-1\n" 220 " jo 5f\n" 221 " bras %3,3f\n" 222 "0: aghi %0,257\n" 223 "1: mvc 0(1,%1),0(%2)\n" 224 " la %1,1(%1)\n" 225 " la %2,1(%2)\n" 226 " aghi %0,-1\n" 227 " jnz 1b\n" 228 " j 5f\n" 229 "2: mvc 0(256,%1),0(%2)\n" 230 " la %1,256(%1)\n" 231 " la %2,256(%2)\n" 232 "3: aghi %0,-256\n" 233 " jnm 2b\n" 234 "4: ex %0,1b-0b(%3)\n" 235 "5: slgr %0,%0\n" 236 "6: sacf 768\n" 237 EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b) 238 : "+a" (size), "+a" (to), "+a" (from), "=a" (tmp1) 239 : : "cc", "memory"); 240 return size; 241 } 242 243 unsigned long __copy_in_user(void __user *to, const void __user *from, unsigned long n) 244 { 245 if (static_branch_likely(&have_mvcos)) 246 return copy_in_user_mvcos(to, from, n); 247 return copy_in_user_mvc(to, from, n); 248 } 249 EXPORT_SYMBOL(__copy_in_user); 250 251 static inline unsigned long clear_user_mvcos(void __user *to, unsigned long size) 252 { 253 register unsigned long reg0 asm("0") = 0x810000UL; 254 unsigned long tmp1, tmp2; 255 256 tmp1 = -4096UL; 257 asm volatile( 258 "0: .insn ss,0xc80000000000,0(%0,%1),0(%4),0\n" 259 " jz 4f\n" 260 "1: algr %0,%2\n" 261 " slgr %1,%2\n" 262 " j 0b\n" 263 "2: la %3,4095(%1)\n"/* %4 = to + 4095 */ 264 " nr %3,%2\n" /* %4 = (to + 4095) & -4096 */ 265 " slgr %3,%1\n" 266 " clgr %0,%3\n" /* copy crosses next page boundary? */ 267 " jnh 5f\n" 268 "3: .insn ss,0xc80000000000,0(%3,%1),0(%4),0\n" 269 " slgr %0,%3\n" 270 " j 5f\n" 271 "4: slgr %0,%0\n" 272 "5:\n" 273 EX_TABLE(0b,2b) EX_TABLE(3b,5b) 274 : "+a" (size), "+a" (to), "+a" (tmp1), "=a" (tmp2) 275 : "a" (empty_zero_page), "d" (reg0) : "cc", "memory"); 276 return size; 277 } 278 279 static inline unsigned long clear_user_xc(void __user *to, unsigned long size) 280 { 281 unsigned long tmp1, tmp2; 282 283 load_kernel_asce(); 284 asm volatile( 285 " sacf 256\n" 286 " aghi %0,-1\n" 287 " jo 5f\n" 288 " bras %3,3f\n" 289 " xc 0(1,%1),0(%1)\n" 290 "0: aghi %0,257\n" 291 " la %2,255(%1)\n" /* %2 = ptr + 255 */ 292 " srl %2,12\n" 293 " sll %2,12\n" /* %2 = (ptr + 255) & -4096 */ 294 " slgr %2,%1\n" 295 " clgr %0,%2\n" /* clear crosses next page boundary? */ 296 " jnh 5f\n" 297 " aghi %2,-1\n" 298 "1: ex %2,0(%3)\n" 299 " aghi %2,1\n" 300 " slgr %0,%2\n" 301 " j 5f\n" 302 "2: xc 0(256,%1),0(%1)\n" 303 " la %1,256(%1)\n" 304 "3: aghi %0,-256\n" 305 " jnm 2b\n" 306 "4: ex %0,0(%3)\n" 307 "5: slgr %0,%0\n" 308 "6: sacf 768\n" 309 EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b) 310 : "+a" (size), "+a" (to), "=a" (tmp1), "=a" (tmp2) 311 : : "cc", "memory"); 312 return size; 313 } 314 315 unsigned long __clear_user(void __user *to, unsigned long size) 316 { 317 if (static_branch_likely(&have_mvcos)) 318 return clear_user_mvcos(to, size); 319 return clear_user_xc(to, size); 320 } 321 EXPORT_SYMBOL(__clear_user); 322 323 static inline unsigned long strnlen_user_srst(const char __user *src, 324 unsigned long size) 325 { 326 register unsigned long reg0 asm("0") = 0; 327 unsigned long tmp1, tmp2; 328 329 asm volatile( 330 " la %2,0(%1)\n" 331 " la %3,0(%0,%1)\n" 332 " slgr %0,%0\n" 333 " sacf 256\n" 334 "0: srst %3,%2\n" 335 " jo 0b\n" 336 " la %0,1(%3)\n" /* strnlen_user results includes \0 */ 337 " slgr %0,%1\n" 338 "1: sacf 768\n" 339 EX_TABLE(0b,1b) 340 : "+a" (size), "+a" (src), "=a" (tmp1), "=a" (tmp2) 341 : "d" (reg0) : "cc", "memory"); 342 return size; 343 } 344 345 unsigned long __strnlen_user(const char __user *src, unsigned long size) 346 { 347 if (unlikely(!size)) 348 return 0; 349 load_kernel_asce(); 350 return strnlen_user_srst(src, size); 351 } 352 EXPORT_SYMBOL(__strnlen_user); 353 354 long __strncpy_from_user(char *dst, const char __user *src, long size) 355 { 356 size_t done, len, offset, len_str; 357 358 if (unlikely(size <= 0)) 359 return 0; 360 done = 0; 361 do { 362 offset = (size_t)src & ~PAGE_MASK; 363 len = min(size - done, PAGE_SIZE - offset); 364 if (copy_from_user(dst, src, len)) 365 return -EFAULT; 366 len_str = strnlen(dst, len); 367 done += len_str; 368 src += len_str; 369 dst += len_str; 370 } while ((len_str == len) && (done < size)); 371 return done; 372 } 373 EXPORT_SYMBOL(__strncpy_from_user); 374 375 static int __init uaccess_init(void) 376 { 377 if (test_facility(27)) 378 static_branch_enable(&have_mvcos); 379 return 0; 380 } 381 early_initcall(uaccess_init); 382