linux/arch/x86/lib/usercopy_32.c
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   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * User address space access functions.
   4 * The non inlined parts of asm-i386/uaccess.h are here.
   5 *
   6 * Copyright 1997 Andi Kleen <ak@muc.de>
   7 * Copyright 1997 Linus Torvalds
   8 */
   9#include <linux/export.h>
  10#include <linux/uaccess.h>
  11#include <asm/mmx.h>
  12#include <asm/asm.h>
  13
  14#ifdef CONFIG_X86_INTEL_USERCOPY
  15/*
  16 * Alignment at which movsl is preferred for bulk memory copies.
  17 */
  18struct movsl_mask movsl_mask __read_mostly;
  19#endif
  20
  21static inline int __movsl_is_ok(unsigned long a1, unsigned long a2, unsigned long n)
  22{
  23#ifdef CONFIG_X86_INTEL_USERCOPY
  24        if (n >= 64 && ((a1 ^ a2) & movsl_mask.mask))
  25                return 0;
  26#endif
  27        return 1;
  28}
  29#define movsl_is_ok(a1, a2, n) \
  30        __movsl_is_ok((unsigned long)(a1), (unsigned long)(a2), (n))
  31
  32/*
  33 * Zero Userspace
  34 */
  35
  36#define __do_clear_user(addr,size)                                      \
  37do {                                                                    \
  38        int __d0;                                                       \
  39        might_fault();                                                  \
  40        __asm__ __volatile__(                                           \
  41                ASM_STAC "\n"                                           \
  42                "0:     rep; stosl\n"                                   \
  43                "       movl %2,%0\n"                                   \
  44                "1:     rep; stosb\n"                                   \
  45                "2: " ASM_CLAC "\n"                                     \
  46                ".section .fixup,\"ax\"\n"                              \
  47                "3:     lea 0(%2,%0,4),%0\n"                            \
  48                "       jmp 2b\n"                                       \
  49                ".previous\n"                                           \
  50                _ASM_EXTABLE_UA(0b, 3b)                                 \
  51                _ASM_EXTABLE_UA(1b, 2b)                                 \
  52                : "=&c"(size), "=&D" (__d0)                             \
  53                : "r"(size & 3), "0"(size / 4), "1"(addr), "a"(0));     \
  54} while (0)
  55
  56/**
  57 * clear_user: - Zero a block of memory in user space.
  58 * @to:   Destination address, in user space.
  59 * @n:    Number of bytes to zero.
  60 *
  61 * Zero a block of memory in user space.
  62 *
  63 * Returns number of bytes that could not be cleared.
  64 * On success, this will be zero.
  65 */
  66unsigned long
  67clear_user(void __user *to, unsigned long n)
  68{
  69        might_fault();
  70        if (access_ok(VERIFY_WRITE, to, n))
  71                __do_clear_user(to, n);
  72        return n;
  73}
  74EXPORT_SYMBOL(clear_user);
  75
  76/**
  77 * __clear_user: - Zero a block of memory in user space, with less checking.
  78 * @to:   Destination address, in user space.
  79 * @n:    Number of bytes to zero.
  80 *
  81 * Zero a block of memory in user space.  Caller must check
  82 * the specified block with access_ok() before calling this function.
  83 *
  84 * Returns number of bytes that could not be cleared.
  85 * On success, this will be zero.
  86 */
  87unsigned long
  88__clear_user(void __user *to, unsigned long n)
  89{
  90        __do_clear_user(to, n);
  91        return n;
  92}
  93EXPORT_SYMBOL(__clear_user);
  94
  95#ifdef CONFIG_X86_INTEL_USERCOPY
  96static unsigned long
  97__copy_user_intel(void __user *to, const void *from, unsigned long size)
  98{
  99        int d0, d1;
 100        __asm__ __volatile__(
 101                       "       .align 2,0x90\n"
 102                       "1:     movl 32(%4), %%eax\n"
 103                       "       cmpl $67, %0\n"
 104                       "       jbe 3f\n"
 105                       "2:     movl 64(%4), %%eax\n"
 106                       "       .align 2,0x90\n"
 107                       "3:     movl 0(%4), %%eax\n"
 108                       "4:     movl 4(%4), %%edx\n"
 109                       "5:     movl %%eax, 0(%3)\n"
 110                       "6:     movl %%edx, 4(%3)\n"
 111                       "7:     movl 8(%4), %%eax\n"
 112                       "8:     movl 12(%4),%%edx\n"
 113                       "9:     movl %%eax, 8(%3)\n"
 114                       "10:    movl %%edx, 12(%3)\n"
 115                       "11:    movl 16(%4), %%eax\n"
 116                       "12:    movl 20(%4), %%edx\n"
 117                       "13:    movl %%eax, 16(%3)\n"
 118                       "14:    movl %%edx, 20(%3)\n"
 119                       "15:    movl 24(%4), %%eax\n"
 120                       "16:    movl 28(%4), %%edx\n"
 121                       "17:    movl %%eax, 24(%3)\n"
 122                       "18:    movl %%edx, 28(%3)\n"
 123                       "19:    movl 32(%4), %%eax\n"
 124                       "20:    movl 36(%4), %%edx\n"
 125                       "21:    movl %%eax, 32(%3)\n"
 126                       "22:    movl %%edx, 36(%3)\n"
 127                       "23:    movl 40(%4), %%eax\n"
 128                       "24:    movl 44(%4), %%edx\n"
 129                       "25:    movl %%eax, 40(%3)\n"
 130                       "26:    movl %%edx, 44(%3)\n"
 131                       "27:    movl 48(%4), %%eax\n"
 132                       "28:    movl 52(%4), %%edx\n"
 133                       "29:    movl %%eax, 48(%3)\n"
 134                       "30:    movl %%edx, 52(%3)\n"
 135                       "31:    movl 56(%4), %%eax\n"
 136                       "32:    movl 60(%4), %%edx\n"
 137                       "33:    movl %%eax, 56(%3)\n"
 138                       "34:    movl %%edx, 60(%3)\n"
 139                       "       addl $-64, %0\n"
 140                       "       addl $64, %4\n"
 141                       "       addl $64, %3\n"
 142                       "       cmpl $63, %0\n"
 143                       "       ja  1b\n"
 144                       "35:    movl  %0, %%eax\n"
 145                       "       shrl  $2, %0\n"
 146                       "       andl  $3, %%eax\n"
 147                       "       cld\n"
 148                       "99:    rep; movsl\n"
 149                       "36:    movl %%eax, %0\n"
 150                       "37:    rep; movsb\n"
 151                       "100:\n"
 152                       ".section .fixup,\"ax\"\n"
 153                       "101:   lea 0(%%eax,%0,4),%0\n"
 154                       "       jmp 100b\n"
 155                       ".previous\n"
 156                       _ASM_EXTABLE_UA(1b, 100b)
 157                       _ASM_EXTABLE_UA(2b, 100b)
 158                       _ASM_EXTABLE_UA(3b, 100b)
 159                       _ASM_EXTABLE_UA(4b, 100b)
 160                       _ASM_EXTABLE_UA(5b, 100b)
 161                       _ASM_EXTABLE_UA(6b, 100b)
 162                       _ASM_EXTABLE_UA(7b, 100b)
 163                       _ASM_EXTABLE_UA(8b, 100b)
 164                       _ASM_EXTABLE_UA(9b, 100b)
 165                       _ASM_EXTABLE_UA(10b, 100b)
 166                       _ASM_EXTABLE_UA(11b, 100b)
 167                       _ASM_EXTABLE_UA(12b, 100b)
 168                       _ASM_EXTABLE_UA(13b, 100b)
 169                       _ASM_EXTABLE_UA(14b, 100b)
 170                       _ASM_EXTABLE_UA(15b, 100b)
 171                       _ASM_EXTABLE_UA(16b, 100b)
 172                       _ASM_EXTABLE_UA(17b, 100b)
 173                       _ASM_EXTABLE_UA(18b, 100b)
 174                       _ASM_EXTABLE_UA(19b, 100b)
 175                       _ASM_EXTABLE_UA(20b, 100b)
 176                       _ASM_EXTABLE_UA(21b, 100b)
 177                       _ASM_EXTABLE_UA(22b, 100b)
 178                       _ASM_EXTABLE_UA(23b, 100b)
 179                       _ASM_EXTABLE_UA(24b, 100b)
 180                       _ASM_EXTABLE_UA(25b, 100b)
 181                       _ASM_EXTABLE_UA(26b, 100b)
 182                       _ASM_EXTABLE_UA(27b, 100b)
 183                       _ASM_EXTABLE_UA(28b, 100b)
 184                       _ASM_EXTABLE_UA(29b, 100b)
 185                       _ASM_EXTABLE_UA(30b, 100b)
 186                       _ASM_EXTABLE_UA(31b, 100b)
 187                       _ASM_EXTABLE_UA(32b, 100b)
 188                       _ASM_EXTABLE_UA(33b, 100b)
 189                       _ASM_EXTABLE_UA(34b, 100b)
 190                       _ASM_EXTABLE_UA(35b, 100b)
 191                       _ASM_EXTABLE_UA(36b, 100b)
 192                       _ASM_EXTABLE_UA(37b, 100b)
 193                       _ASM_EXTABLE_UA(99b, 101b)
 194                       : "=&c"(size), "=&D" (d0), "=&S" (d1)
 195                       :  "1"(to), "2"(from), "0"(size)
 196                       : "eax", "edx", "memory");
 197        return size;
 198}
 199
 200static unsigned long __copy_user_intel_nocache(void *to,
 201                                const void __user *from, unsigned long size)
 202{
 203        int d0, d1;
 204
 205        __asm__ __volatile__(
 206               "        .align 2,0x90\n"
 207               "0:      movl 32(%4), %%eax\n"
 208               "        cmpl $67, %0\n"
 209               "        jbe 2f\n"
 210               "1:      movl 64(%4), %%eax\n"
 211               "        .align 2,0x90\n"
 212               "2:      movl 0(%4), %%eax\n"
 213               "21:     movl 4(%4), %%edx\n"
 214               "        movnti %%eax, 0(%3)\n"
 215               "        movnti %%edx, 4(%3)\n"
 216               "3:      movl 8(%4), %%eax\n"
 217               "31:     movl 12(%4),%%edx\n"
 218               "        movnti %%eax, 8(%3)\n"
 219               "        movnti %%edx, 12(%3)\n"
 220               "4:      movl 16(%4), %%eax\n"
 221               "41:     movl 20(%4), %%edx\n"
 222               "        movnti %%eax, 16(%3)\n"
 223               "        movnti %%edx, 20(%3)\n"
 224               "10:     movl 24(%4), %%eax\n"
 225               "51:     movl 28(%4), %%edx\n"
 226               "        movnti %%eax, 24(%3)\n"
 227               "        movnti %%edx, 28(%3)\n"
 228               "11:     movl 32(%4), %%eax\n"
 229               "61:     movl 36(%4), %%edx\n"
 230               "        movnti %%eax, 32(%3)\n"
 231               "        movnti %%edx, 36(%3)\n"
 232               "12:     movl 40(%4), %%eax\n"
 233               "71:     movl 44(%4), %%edx\n"
 234               "        movnti %%eax, 40(%3)\n"
 235               "        movnti %%edx, 44(%3)\n"
 236               "13:     movl 48(%4), %%eax\n"
 237               "81:     movl 52(%4), %%edx\n"
 238               "        movnti %%eax, 48(%3)\n"
 239               "        movnti %%edx, 52(%3)\n"
 240               "14:     movl 56(%4), %%eax\n"
 241               "91:     movl 60(%4), %%edx\n"
 242               "        movnti %%eax, 56(%3)\n"
 243               "        movnti %%edx, 60(%3)\n"
 244               "        addl $-64, %0\n"
 245               "        addl $64, %4\n"
 246               "        addl $64, %3\n"
 247               "        cmpl $63, %0\n"
 248               "        ja  0b\n"
 249               "        sfence \n"
 250               "5:      movl  %0, %%eax\n"
 251               "        shrl  $2, %0\n"
 252               "        andl $3, %%eax\n"
 253               "        cld\n"
 254               "6:      rep; movsl\n"
 255               "        movl %%eax,%0\n"
 256               "7:      rep; movsb\n"
 257               "8:\n"
 258               ".section .fixup,\"ax\"\n"
 259               "9:      lea 0(%%eax,%0,4),%0\n"
 260               "16:     jmp 8b\n"
 261               ".previous\n"
 262               _ASM_EXTABLE_UA(0b, 16b)
 263               _ASM_EXTABLE_UA(1b, 16b)
 264               _ASM_EXTABLE_UA(2b, 16b)
 265               _ASM_EXTABLE_UA(21b, 16b)
 266               _ASM_EXTABLE_UA(3b, 16b)
 267               _ASM_EXTABLE_UA(31b, 16b)
 268               _ASM_EXTABLE_UA(4b, 16b)
 269               _ASM_EXTABLE_UA(41b, 16b)
 270               _ASM_EXTABLE_UA(10b, 16b)
 271               _ASM_EXTABLE_UA(51b, 16b)
 272               _ASM_EXTABLE_UA(11b, 16b)
 273               _ASM_EXTABLE_UA(61b, 16b)
 274               _ASM_EXTABLE_UA(12b, 16b)
 275               _ASM_EXTABLE_UA(71b, 16b)
 276               _ASM_EXTABLE_UA(13b, 16b)
 277               _ASM_EXTABLE_UA(81b, 16b)
 278               _ASM_EXTABLE_UA(14b, 16b)
 279               _ASM_EXTABLE_UA(91b, 16b)
 280               _ASM_EXTABLE_UA(6b, 9b)
 281               _ASM_EXTABLE_UA(7b, 16b)
 282               : "=&c"(size), "=&D" (d0), "=&S" (d1)
 283               :  "1"(to), "2"(from), "0"(size)
 284               : "eax", "edx", "memory");
 285        return size;
 286}
 287
 288#else
 289
 290/*
 291 * Leave these declared but undefined.  They should not be any references to
 292 * them
 293 */
 294unsigned long __copy_user_intel(void __user *to, const void *from,
 295                                        unsigned long size);
 296#endif /* CONFIG_X86_INTEL_USERCOPY */
 297
 298/* Generic arbitrary sized copy.  */
 299#define __copy_user(to, from, size)                                     \
 300do {                                                                    \
 301        int __d0, __d1, __d2;                                           \
 302        __asm__ __volatile__(                                           \
 303                "       cmp  $7,%0\n"                                   \
 304                "       jbe  1f\n"                                      \
 305                "       movl %1,%0\n"                                   \
 306                "       negl %0\n"                                      \
 307                "       andl $7,%0\n"                                   \
 308                "       subl %0,%3\n"                                   \
 309                "4:     rep; movsb\n"                                   \
 310                "       movl %3,%0\n"                                   \
 311                "       shrl $2,%0\n"                                   \
 312                "       andl $3,%3\n"                                   \
 313                "       .align 2,0x90\n"                                \
 314                "0:     rep; movsl\n"                                   \
 315                "       movl %3,%0\n"                                   \
 316                "1:     rep; movsb\n"                                   \
 317                "2:\n"                                                  \
 318                ".section .fixup,\"ax\"\n"                              \
 319                "5:     addl %3,%0\n"                                   \
 320                "       jmp 2b\n"                                       \
 321                "3:     lea 0(%3,%0,4),%0\n"                            \
 322                "       jmp 2b\n"                                       \
 323                ".previous\n"                                           \
 324                _ASM_EXTABLE_UA(4b, 5b)                                 \
 325                _ASM_EXTABLE_UA(0b, 3b)                                 \
 326                _ASM_EXTABLE_UA(1b, 2b)                                 \
 327                : "=&c"(size), "=&D" (__d0), "=&S" (__d1), "=r"(__d2)   \
 328                : "3"(size), "0"(size), "1"(to), "2"(from)              \
 329                : "memory");                                            \
 330} while (0)
 331
 332unsigned long __copy_user_ll(void *to, const void *from, unsigned long n)
 333{
 334        __uaccess_begin_nospec();
 335        if (movsl_is_ok(to, from, n))
 336                __copy_user(to, from, n);
 337        else
 338                n = __copy_user_intel(to, from, n);
 339        __uaccess_end();
 340        return n;
 341}
 342EXPORT_SYMBOL(__copy_user_ll);
 343
 344unsigned long __copy_from_user_ll_nocache_nozero(void *to, const void __user *from,
 345                                        unsigned long n)
 346{
 347        __uaccess_begin_nospec();
 348#ifdef CONFIG_X86_INTEL_USERCOPY
 349        if (n > 64 && static_cpu_has(X86_FEATURE_XMM2))
 350                n = __copy_user_intel_nocache(to, from, n);
 351        else
 352                __copy_user(to, from, n);
 353#else
 354        __copy_user(to, from, n);
 355#endif
 356        __uaccess_end();
 357        return n;
 358}
 359EXPORT_SYMBOL(__copy_from_user_ll_nocache_nozero);
 360