linux/arch/s390/lib/uaccess.c
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   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
  20void 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
  38static DEFINE_STATIC_KEY_FALSE(have_mvcos);
  39
  40static int __init uaccess_init(void)
  41{
  42        if (test_facility(27))
  43                static_branch_enable(&have_mvcos);
  44        return 0;
  45}
  46early_initcall(uaccess_init);
  47
  48static inline int copy_with_mvcos(void)
  49{
  50        if (static_branch_likely(&have_mvcos))
  51                return 1;
  52        return 0;
  53}
  54#else
  55static inline int copy_with_mvcos(void)
  56{
  57        return 1;
  58}
  59#endif
  60
  61static 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
  92static 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
 126unsigned 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}
 132EXPORT_SYMBOL(raw_copy_from_user);
 133
 134static 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
 165static 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
 199unsigned 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}
 205EXPORT_SYMBOL(raw_copy_to_user);
 206
 207static 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
 231static 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
 262unsigned 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}
 268EXPORT_SYMBOL(raw_copy_in_user);
 269
 270static 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
 299static 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
 334unsigned 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}
 340EXPORT_SYMBOL(__clear_user);
 341
 342static 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
 365unsigned 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}
 371EXPORT_SYMBOL(__strnlen_user);
 372
 373long __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}
 392EXPORT_SYMBOL(__strncpy_from_user);
 393
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