LXR linux/tools/testing/selftests/rseq/rseq-arm.h

   1/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
   2/*
   3 * rseq-arm.h
   4 *
   5 * (C) Copyright 2016-2018 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   6 */
   7
   8/*
   9 * - ARM little endian
  10 *
  11 * RSEQ_SIG uses the udf A32 instruction with an uncommon immediate operand
  12 * value 0x5de3. This traps if user-space reaches this instruction by mistake,
  13 * and the uncommon operand ensures the kernel does not move the instruction
  14 * pointer to attacker-controlled code on rseq abort.
  15 *
  16 * The instruction pattern in the A32 instruction set is:
  17 *
  18 * e7f5def3    udf    #24035    ; 0x5de3
  19 *
  20 * This translates to the following instruction pattern in the T16 instruction
  21 * set:
  22 *
  23 * little endian:
  24 * def3        udf    #243      ; 0xf3
  25 * e7f5        b.n    <7f5>
  26 *
  27 * - ARMv6+ big endian (BE8):
  28 *
  29 * ARMv6+ -mbig-endian generates mixed endianness code vs data: little-endian
  30 * code and big-endian data. The data value of the signature needs to have its
  31 * byte order reversed to generate the trap instruction:
  32 *
  33 * Data: 0xf3def5e7
  34 *
  35 * Translates to this A32 instruction pattern:
  36 *
  37 * e7f5def3    udf    #24035    ; 0x5de3
  38 *
  39 * Translates to this T16 instruction pattern:
  40 *
  41 * def3        udf    #243      ; 0xf3
  42 * e7f5        b.n    <7f5>
  43 *
  44 * - Prior to ARMv6 big endian (BE32):
  45 *
  46 * Prior to ARMv6, -mbig-endian generates big-endian code and data
  47 * (which match), so the endianness of the data representation of the
  48 * signature should not be reversed. However, the choice between BE32
  49 * and BE8 is done by the linker, so we cannot know whether code and
  50 * data endianness will be mixed before the linker is invoked. So rather
  51 * than try to play tricks with the linker, the rseq signature is simply
  52 * data (not a trap instruction) prior to ARMv6 on big endian. This is
  53 * why the signature is expressed as data (.word) rather than as
  54 * instruction (.inst) in assembler.
  55 */
  56
  57#ifdef __ARMEB__
  58#define RSEQ_SIG    0xf3def5e7      /* udf    #24035    ; 0x5de3 (ARMv6+) */
  59#else
  60#define RSEQ_SIG    0xe7f5def3      /* udf    #24035    ; 0x5de3 */
  61#endif
  62
  63#define rseq_smp_mb()   __asm__ __volatile__ ("dmb" ::: "memory", "cc")
  64#define rseq_smp_rmb()  __asm__ __volatile__ ("dmb" ::: "memory", "cc")
  65#define rseq_smp_wmb()  __asm__ __volatile__ ("dmb" ::: "memory", "cc")
  66
  67#define rseq_smp_load_acquire(p)                                        \
  68__extension__ ({                                                        \
  69        __typeof(*p) ____p1 = RSEQ_READ_ONCE(*p);                       \
  70        rseq_smp_mb();                                                  \
  71        ____p1;                                                         \
  72})
  73
  74#define rseq_smp_acquire__after_ctrl_dep()      rseq_smp_rmb()
  75
  76#define rseq_smp_store_release(p, v)                                    \
  77do {                                                                    \
  78        rseq_smp_mb();                                                  \
  79        RSEQ_WRITE_ONCE(*p, v);                                         \
  80} while (0)
  81
  82#ifdef RSEQ_SKIP_FASTPATH
  83#include "rseq-skip.h"
  84#else /* !RSEQ_SKIP_FASTPATH */
  85
  86#define __RSEQ_ASM_DEFINE_TABLE(label, version, flags, start_ip,        \
  87                                post_commit_offset, abort_ip)           \
  88                ".pushsection __rseq_cs, \"aw\"\n\t"                    \
  89                ".balign 32\n\t"                                        \
  90                __rseq_str(label) ":\n\t"                                       \
  91                ".word " __rseq_str(version) ", " __rseq_str(flags) "\n\t" \
  92                ".word " __rseq_str(start_ip) ", 0x0, " __rseq_str(post_commit_offset) ", 0x0, " __rseq_str(abort_ip) ", 0x0\n\t" \
  93                ".popsection\n\t"                                       \
  94                ".pushsection __rseq_cs_ptr_array, \"aw\"\n\t"          \
  95                ".word " __rseq_str(label) "b, 0x0\n\t"                 \
  96                ".popsection\n\t"
  97
  98#define RSEQ_ASM_DEFINE_TABLE(label, start_ip, post_commit_ip, abort_ip) \
  99        __RSEQ_ASM_DEFINE_TABLE(label, 0x0, 0x0, start_ip,              \
 100                                (post_commit_ip - start_ip), abort_ip)
 101
 102/*
 103 * Exit points of a rseq critical section consist of all instructions outside
 104 * of the critical section where a critical section can either branch to or
 105 * reach through the normal course of its execution. The abort IP and the
 106 * post-commit IP are already part of the __rseq_cs section and should not be
 107 * explicitly defined as additional exit points. Knowing all exit points is
 108 * useful to assist debuggers stepping over the critical section.
 109 */
 110#define RSEQ_ASM_DEFINE_EXIT_POINT(start_ip, exit_ip)                   \
 111                ".pushsection __rseq_exit_point_array, \"aw\"\n\t"      \
 112                ".word " __rseq_str(start_ip) ", 0x0, " __rseq_str(exit_ip) ", 0x0\n\t" \
 113                ".popsection\n\t"
 114
 115#define RSEQ_ASM_STORE_RSEQ_CS(label, cs_label, rseq_cs)                \
 116                RSEQ_INJECT_ASM(1)                                      \
 117                "adr r0, " __rseq_str(cs_label) "\n\t"                  \
 118                "str r0, %[" __rseq_str(rseq_cs) "]\n\t"                \
 119                __rseq_str(label) ":\n\t"
 120
 121#define RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, label)              \
 122                RSEQ_INJECT_ASM(2)                                      \
 123                "ldr r0, %[" __rseq_str(current_cpu_id) "]\n\t" \
 124                "cmp %[" __rseq_str(cpu_id) "], r0\n\t"         \
 125                "bne " __rseq_str(label) "\n\t"
 126
 127#define __RSEQ_ASM_DEFINE_ABORT(table_label, label, teardown,           \
 128                                abort_label, version, flags,            \
 129                                start_ip, post_commit_offset, abort_ip) \
 130                ".balign 32\n\t"                                        \
 131                __rseq_str(table_label) ":\n\t"                         \
 132                ".word " __rseq_str(version) ", " __rseq_str(flags) "\n\t" \
 133                ".word " __rseq_str(start_ip) ", 0x0, " __rseq_str(post_commit_offset) ", 0x0, " __rseq_str(abort_ip) ", 0x0\n\t" \
 134                ".word " __rseq_str(RSEQ_SIG) "\n\t"                    \
 135                __rseq_str(label) ":\n\t"                               \
 136                teardown                                                \
 137                "b %l[" __rseq_str(abort_label) "]\n\t"
 138
 139#define RSEQ_ASM_DEFINE_ABORT(table_label, label, teardown, abort_label, \
 140                              start_ip, post_commit_ip, abort_ip)       \
 141        __RSEQ_ASM_DEFINE_ABORT(table_label, label, teardown,           \
 142                                abort_label, 0x0, 0x0, start_ip,        \
 143                                (post_commit_ip - start_ip), abort_ip)
 144
 145#define RSEQ_ASM_DEFINE_CMPFAIL(label, teardown, cmpfail_label)         \
 146                __rseq_str(label) ":\n\t"                               \
 147                teardown                                                \
 148                "b %l[" __rseq_str(cmpfail_label) "]\n\t"
 149
 150#define rseq_workaround_gcc_asm_size_guess()    __asm__ __volatile__("")
 151
 152static inline __attribute__((always_inline))
 153int rseq_cmpeqv_storev(intptr_t *v, intptr_t expect, intptr_t newv, int cpu)
 154{
 155        RSEQ_INJECT_C(9)
 156
 157        rseq_workaround_gcc_asm_size_guess();
 158        __asm__ __volatile__ goto (
 159                RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */
 160                RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
 161#ifdef RSEQ_COMPARE_TWICE
 162                RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
 163                RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
 164#endif
 165                /* Start rseq by storing table entry pointer into rseq_cs. */
 166                RSEQ_ASM_STORE_RSEQ_CS(1, 3f, rseq_cs)
 167                RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
 168                RSEQ_INJECT_ASM(3)
 169                "ldr r0, %[v]\n\t"
 170                "cmp %[expect], r0\n\t"
 171                "bne %l[cmpfail]\n\t"
 172                RSEQ_INJECT_ASM(4)
 173#ifdef RSEQ_COMPARE_TWICE
 174                RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
 175                "ldr r0, %[v]\n\t"
 176                "cmp %[expect], r0\n\t"
 177                "bne %l[error2]\n\t"
 178#endif
 179                /* final store */
 180                "str %[newv], %[v]\n\t"
 181                "2:\n\t"
 182                RSEQ_INJECT_ASM(5)
 183                "b 5f\n\t"
 184                RSEQ_ASM_DEFINE_ABORT(3, 4, "", abort, 1b, 2b, 4f)
 185                "5:\n\t"
 186                : /* gcc asm goto does not allow outputs */
 187                : [cpu_id]              "r" (cpu),
 188                  [current_cpu_id]      "m" (__rseq_abi.cpu_id),
 189                  [rseq_cs]             "m" (__rseq_abi.rseq_cs),
 190                  [v]                   "m" (*v),
 191                  [expect]              "r" (expect),
 192                  [newv]                "r" (newv)
 193                  RSEQ_INJECT_INPUT
 194                : "r0", "memory", "cc"
 195                  RSEQ_INJECT_CLOBBER
 196                : abort, cmpfail
 197#ifdef RSEQ_COMPARE_TWICE
 198                  , error1, error2
 199#endif
 200        );
 201        rseq_workaround_gcc_asm_size_guess();
 202        return 0;
 203abort:
 204        rseq_workaround_gcc_asm_size_guess();
 205        RSEQ_INJECT_FAILED
 206        return -1;
 207cmpfail:
 208        rseq_workaround_gcc_asm_size_guess();
 209        return 1;
 210#ifdef RSEQ_COMPARE_TWICE
 211error1:
 212        rseq_bug("cpu_id comparison failed");
 213error2:
 214        rseq_bug("expected value comparison failed");
 215#endif
 216}
 217
 218static inline __attribute__((always_inline))
 219int rseq_cmpnev_storeoffp_load(intptr_t *v, intptr_t expectnot,
 220                               off_t voffp, intptr_t *load, int cpu)
 221{
 222        RSEQ_INJECT_C(9)
 223
 224        rseq_workaround_gcc_asm_size_guess();
 225        __asm__ __volatile__ goto (
 226                RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */
 227                RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
 228#ifdef RSEQ_COMPARE_TWICE
 229                RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
 230                RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
 231#endif
 232                /* Start rseq by storing table entry pointer into rseq_cs. */
 233                RSEQ_ASM_STORE_RSEQ_CS(1, 3f, rseq_cs)
 234                RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
 235                RSEQ_INJECT_ASM(3)
 236                "ldr r0, %[v]\n\t"
 237                "cmp %[expectnot], r0\n\t"
 238                "beq %l[cmpfail]\n\t"
 239                RSEQ_INJECT_ASM(4)
 240#ifdef RSEQ_COMPARE_TWICE
 241                RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
 242                "ldr r0, %[v]\n\t"
 243                "cmp %[expectnot], r0\n\t"
 244                "beq %l[error2]\n\t"
 245#endif
 246                "str r0, %[load]\n\t"
 247                "add r0, %[voffp]\n\t"
 248                "ldr r0, [r0]\n\t"
 249                /* final store */
 250                "str r0, %[v]\n\t"
 251                "2:\n\t"
 252                RSEQ_INJECT_ASM(5)
 253                "b 5f\n\t"
 254                RSEQ_ASM_DEFINE_ABORT(3, 4, "", abort, 1b, 2b, 4f)
 255                "5:\n\t"
 256                : /* gcc asm goto does not allow outputs */
 257                : [cpu_id]              "r" (cpu),
 258                  [current_cpu_id]      "m" (__rseq_abi.cpu_id),
 259                  [rseq_cs]             "m" (__rseq_abi.rseq_cs),
 260                  /* final store input */
 261                  [v]                   "m" (*v),
 262                  [expectnot]           "r" (expectnot),
 263                  [voffp]               "Ir" (voffp),
 264                  [load]                "m" (*load)
 265                  RSEQ_INJECT_INPUT
 266                : "r0", "memory", "cc"
 267                  RSEQ_INJECT_CLOBBER
 268                : abort, cmpfail
 269#ifdef RSEQ_COMPARE_TWICE
 270                  , error1, error2
 271#endif
 272        );
 273        rseq_workaround_gcc_asm_size_guess();
 274        return 0;
 275abort:
 276        rseq_workaround_gcc_asm_size_guess();
 277        RSEQ_INJECT_FAILED
 278        return -1;
 279cmpfail:
 280        rseq_workaround_gcc_asm_size_guess();
 281        return 1;
 282#ifdef RSEQ_COMPARE_TWICE
 283error1:
 284        rseq_bug("cpu_id comparison failed");
 285error2:
 286        rseq_bug("expected value comparison failed");
 287#endif
 288}
 289
 290static inline __attribute__((always_inline))
 291int rseq_addv(intptr_t *v, intptr_t count, int cpu)
 292{
 293        RSEQ_INJECT_C(9)
 294
 295        rseq_workaround_gcc_asm_size_guess();
 296        __asm__ __volatile__ goto (
 297                RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */
 298#ifdef RSEQ_COMPARE_TWICE
 299                RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
 300#endif
 301                /* Start rseq by storing table entry pointer into rseq_cs. */
 302                RSEQ_ASM_STORE_RSEQ_CS(1, 3f, rseq_cs)
 303                RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
 304                RSEQ_INJECT_ASM(3)
 305#ifdef RSEQ_COMPARE_TWICE
 306                RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
 307#endif
 308                "ldr r0, %[v]\n\t"
 309                "add r0, %[count]\n\t"
 310                /* final store */
 311                "str r0, %[v]\n\t"
 312                "2:\n\t"
 313                RSEQ_INJECT_ASM(4)
 314                "b 5f\n\t"
 315                RSEQ_ASM_DEFINE_ABORT(3, 4, "", abort, 1b, 2b, 4f)
 316                "5:\n\t"
 317                : /* gcc asm goto does not allow outputs */
 318                : [cpu_id]              "r" (cpu),
 319                  [current_cpu_id]      "m" (__rseq_abi.cpu_id),
 320                  [rseq_cs]             "m" (__rseq_abi.rseq_cs),
 321                  [v]                   "m" (*v),
 322                  [count]               "Ir" (count)
 323                  RSEQ_INJECT_INPUT
 324                : "r0", "memory", "cc"
 325                  RSEQ_INJECT_CLOBBER
 326                : abort
 327#ifdef RSEQ_COMPARE_TWICE
 328                  , error1
 329#endif
 330        );
 331        rseq_workaround_gcc_asm_size_guess();
 332        return 0;
 333abort:
 334        rseq_workaround_gcc_asm_size_guess();
 335        RSEQ_INJECT_FAILED
 336        return -1;
 337#ifdef RSEQ_COMPARE_TWICE
 338error1:
 339        rseq_bug("cpu_id comparison failed");
 340#endif
 341}
 342
 343static inline __attribute__((always_inline))
 344int rseq_cmpeqv_trystorev_storev(intptr_t *v, intptr_t expect,
 345                                 intptr_t *v2, intptr_t newv2,
 346                                 intptr_t newv, int cpu)
 347{
 348        RSEQ_INJECT_C(9)
 349
 350        rseq_workaround_gcc_asm_size_guess();
 351        __asm__ __volatile__ goto (
 352                RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */
 353                RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
 354#ifdef RSEQ_COMPARE_TWICE
 355                RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
 356                RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
 357#endif
 358                /* Start rseq by storing table entry pointer into rseq_cs. */
 359                RSEQ_ASM_STORE_RSEQ_CS(1, 3f, rseq_cs)
 360                RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
 361                RSEQ_INJECT_ASM(3)
 362                "ldr r0, %[v]\n\t"
 363                "cmp %[expect], r0\n\t"
 364                "bne %l[cmpfail]\n\t"
 365                RSEQ_INJECT_ASM(4)
 366#ifdef RSEQ_COMPARE_TWICE
 367                RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
 368                "ldr r0, %[v]\n\t"
 369                "cmp %[expect], r0\n\t"
 370                "bne %l[error2]\n\t"
 371#endif
 372                /* try store */
 373                "str %[newv2], %[v2]\n\t"
 374                RSEQ_INJECT_ASM(5)
 375                /* final store */
 376                "str %[newv], %[v]\n\t"
 377                "2:\n\t"
 378                RSEQ_INJECT_ASM(6)
 379                "b 5f\n\t"
 380                RSEQ_ASM_DEFINE_ABORT(3, 4, "", abort, 1b, 2b, 4f)
 381                "5:\n\t"
 382                : /* gcc asm goto does not allow outputs */
 383                : [cpu_id]              "r" (cpu),
 384                  [current_cpu_id]      "m" (__rseq_abi.cpu_id),
 385                  [rseq_cs]             "m" (__rseq_abi.rseq_cs),
 386                  /* try store input */
 387                  [v2]                  "m" (*v2),
 388                  [newv2]               "r" (newv2),
 389                  /* final store input */
 390                  [v]                   "m" (*v),
 391                  [expect]              "r" (expect),
 392                  [newv]                "r" (newv)
 393                  RSEQ_INJECT_INPUT
 394                : "r0", "memory", "cc"
 395                  RSEQ_INJECT_CLOBBER
 396                : abort, cmpfail
 397#ifdef RSEQ_COMPARE_TWICE
 398                  , error1, error2
 399#endif
 400        );
 401        rseq_workaround_gcc_asm_size_guess();
 402        return 0;
 403abort:
 404        rseq_workaround_gcc_asm_size_guess();
 405        RSEQ_INJECT_FAILED
 406        return -1;
 407cmpfail:
 408        rseq_workaround_gcc_asm_size_guess();
 409        return 1;
 410#ifdef RSEQ_COMPARE_TWICE
 411error1:
 412        rseq_bug("cpu_id comparison failed");
 413error2:
 414        rseq_bug("expected value comparison failed");
 415#endif
 416}
 417
 418static inline __attribute__((always_inline))
 419int rseq_cmpeqv_trystorev_storev_release(intptr_t *v, intptr_t expect,
 420                                         intptr_t *v2, intptr_t newv2,
 421                                         intptr_t newv, int cpu)
 422{
 423        RSEQ_INJECT_C(9)
 424
 425        rseq_workaround_gcc_asm_size_guess();
 426        __asm__ __volatile__ goto (
 427                RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */
 428                RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
 429#ifdef RSEQ_COMPARE_TWICE
 430                RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
 431                RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
 432#endif
 433                /* Start rseq by storing table entry pointer into rseq_cs. */
 434                RSEQ_ASM_STORE_RSEQ_CS(1, 3f, rseq_cs)
 435                RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
 436                RSEQ_INJECT_ASM(3)
 437                "ldr r0, %[v]\n\t"
 438                "cmp %[expect], r0\n\t"
 439                "bne %l[cmpfail]\n\t"
 440                RSEQ_INJECT_ASM(4)
 441#ifdef RSEQ_COMPARE_TWICE
 442                RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
 443                "ldr r0, %[v]\n\t"
 444                "cmp %[expect], r0\n\t"
 445                "bne %l[error2]\n\t"
 446#endif
 447                /* try store */
 448                "str %[newv2], %[v2]\n\t"
 449                RSEQ_INJECT_ASM(5)
 450                "dmb\n\t"       /* full mb provides store-release */
 451                /* final store */
 452                "str %[newv], %[v]\n\t"
 453                "2:\n\t"
 454                RSEQ_INJECT_ASM(6)
 455                "b 5f\n\t"
 456                RSEQ_ASM_DEFINE_ABORT(3, 4, "", abort, 1b, 2b, 4f)
 457                "5:\n\t"
 458                : /* gcc asm goto does not allow outputs */
 459                : [cpu_id]              "r" (cpu),
 460                  [current_cpu_id]      "m" (__rseq_abi.cpu_id),
 461                  [rseq_cs]             "m" (__rseq_abi.rseq_cs),
 462                  /* try store input */
 463                  [v2]                  "m" (*v2),
 464                  [newv2]               "r" (newv2),
 465                  /* final store input */
 466                  [v]                   "m" (*v),
 467                  [expect]              "r" (expect),
 468                  [newv]                "r" (newv)
 469                  RSEQ_INJECT_INPUT
 470                : "r0", "memory", "cc"
 471                  RSEQ_INJECT_CLOBBER
 472                : abort, cmpfail
 473#ifdef RSEQ_COMPARE_TWICE
 474                  , error1, error2
 475#endif
 476        );
 477        rseq_workaround_gcc_asm_size_guess();
 478        return 0;
 479abort:
 480        rseq_workaround_gcc_asm_size_guess();
 481        RSEQ_INJECT_FAILED
 482        return -1;
 483cmpfail:
 484        rseq_workaround_gcc_asm_size_guess();
 485        return 1;
 486#ifdef RSEQ_COMPARE_TWICE
 487error1:
 488        rseq_bug("cpu_id comparison failed");
 489error2:
 490        rseq_bug("expected value comparison failed");
 491#endif
 492}
 493
 494static inline __attribute__((always_inline))
 495int rseq_cmpeqv_cmpeqv_storev(intptr_t *v, intptr_t expect,
 496                              intptr_t *v2, intptr_t expect2,
 497                              intptr_t newv, int cpu)
 498{
 499        RSEQ_INJECT_C(9)
 500
 501        rseq_workaround_gcc_asm_size_guess();
 502        __asm__ __volatile__ goto (
 503                RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */
 504                RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
 505#ifdef RSEQ_COMPARE_TWICE
 506                RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
 507                RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
 508                RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error3])
 509#endif
 510                /* Start rseq by storing table entry pointer into rseq_cs. */
 511                RSEQ_ASM_STORE_RSEQ_CS(1, 3f, rseq_cs)
 512                RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
 513                RSEQ_INJECT_ASM(3)
 514                "ldr r0, %[v]\n\t"
 515                "cmp %[expect], r0\n\t"
 516                "bne %l[cmpfail]\n\t"
 517                RSEQ_INJECT_ASM(4)
 518                "ldr r0, %[v2]\n\t"
 519                "cmp %[expect2], r0\n\t"
 520                "bne %l[cmpfail]\n\t"
 521                RSEQ_INJECT_ASM(5)
 522#ifdef RSEQ_COMPARE_TWICE
 523                RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
 524                "ldr r0, %[v]\n\t"
 525                "cmp %[expect], r0\n\t"
 526                "bne %l[error2]\n\t"
 527                "ldr r0, %[v2]\n\t"
 528                "cmp %[expect2], r0\n\t"
 529                "bne %l[error3]\n\t"
 530#endif
 531                /* final store */
 532                "str %[newv], %[v]\n\t"
 533                "2:\n\t"
 534                RSEQ_INJECT_ASM(6)
 535                "b 5f\n\t"
 536                RSEQ_ASM_DEFINE_ABORT(3, 4, "", abort, 1b, 2b, 4f)
 537                "5:\n\t"
 538                : /* gcc asm goto does not allow outputs */
 539                : [cpu_id]              "r" (cpu),
 540                  [current_cpu_id]      "m" (__rseq_abi.cpu_id),
 541                  [rseq_cs]             "m" (__rseq_abi.rseq_cs),
 542                  /* cmp2 input */
 543                  [v2]                  "m" (*v2),
 544                  [expect2]             "r" (expect2),
 545                  /* final store input */
 546                  [v]                   "m" (*v),
 547                  [expect]              "r" (expect),
 548                  [newv]                "r" (newv)
 549                  RSEQ_INJECT_INPUT
 550                : "r0", "memory", "cc"
 551                  RSEQ_INJECT_CLOBBER
 552                : abort, cmpfail
 553#ifdef RSEQ_COMPARE_TWICE
 554                  , error1, error2, error3
 555#endif
 556        );
 557        rseq_workaround_gcc_asm_size_guess();
 558        return 0;
 559abort:
 560        rseq_workaround_gcc_asm_size_guess();
 561        RSEQ_INJECT_FAILED
 562        return -1;
 563cmpfail:
 564        rseq_workaround_gcc_asm_size_guess();
 565        return 1;
 566#ifdef RSEQ_COMPARE_TWICE
 567error1:
 568        rseq_bug("cpu_id comparison failed");
 569error2:
 570        rseq_bug("1st expected value comparison failed");
 571error3:
 572        rseq_bug("2nd expected value comparison failed");
 573#endif
 574}
 575
 576static inline __attribute__((always_inline))
 577int rseq_cmpeqv_trymemcpy_storev(intptr_t *v, intptr_t expect,
 578                                 void *dst, void *src, size_t len,
 579                                 intptr_t newv, int cpu)
 580{
 581        uint32_t rseq_scratch[3];
 582
 583        RSEQ_INJECT_C(9)
 584
 585        rseq_workaround_gcc_asm_size_guess();
 586        __asm__ __volatile__ goto (
 587                RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */
 588                RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
 589#ifdef RSEQ_COMPARE_TWICE
 590                RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
 591                RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
 592#endif
 593                "str %[src], %[rseq_scratch0]\n\t"
 594                "str %[dst], %[rseq_scratch1]\n\t"
 595                "str %[len], %[rseq_scratch2]\n\t"
 596                /* Start rseq by storing table entry pointer into rseq_cs. */
 597                RSEQ_ASM_STORE_RSEQ_CS(1, 3f, rseq_cs)
 598                RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
 599                RSEQ_INJECT_ASM(3)
 600                "ldr r0, %[v]\n\t"
 601                "cmp %[expect], r0\n\t"
 602                "bne 5f\n\t"
 603                RSEQ_INJECT_ASM(4)
 604#ifdef RSEQ_COMPARE_TWICE
 605                RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 6f)
 606                "ldr r0, %[v]\n\t"
 607                "cmp %[expect], r0\n\t"
 608                "bne 7f\n\t"
 609#endif
 610                /* try memcpy */
 611                "cmp %[len], #0\n\t" \
 612                "beq 333f\n\t" \
 613                "222:\n\t" \
 614                "ldrb %%r0, [%[src]]\n\t" \
 615                "strb %%r0, [%[dst]]\n\t" \
 616                "adds %[src], #1\n\t" \
 617                "adds %[dst], #1\n\t" \
 618                "subs %[len], #1\n\t" \
 619                "bne 222b\n\t" \
 620                "333:\n\t" \
 621                RSEQ_INJECT_ASM(5)
 622                /* final store */
 623                "str %[newv], %[v]\n\t"
 624                "2:\n\t"
 625                RSEQ_INJECT_ASM(6)
 626                /* teardown */
 627                "ldr %[len], %[rseq_scratch2]\n\t"
 628                "ldr %[dst], %[rseq_scratch1]\n\t"
 629                "ldr %[src], %[rseq_scratch0]\n\t"
 630                "b 8f\n\t"
 631                RSEQ_ASM_DEFINE_ABORT(3, 4,
 632                                      /* teardown */
 633                                      "ldr %[len], %[rseq_scratch2]\n\t"
 634                                      "ldr %[dst], %[rseq_scratch1]\n\t"
 635                                      "ldr %[src], %[rseq_scratch0]\n\t",
 636                                      abort, 1b, 2b, 4f)
 637                RSEQ_ASM_DEFINE_CMPFAIL(5,
 638                                        /* teardown */
 639                                        "ldr %[len], %[rseq_scratch2]\n\t"
 640                                        "ldr %[dst], %[rseq_scratch1]\n\t"
 641                                        "ldr %[src], %[rseq_scratch0]\n\t",
 642                                        cmpfail)
 643#ifdef RSEQ_COMPARE_TWICE
 644                RSEQ_ASM_DEFINE_CMPFAIL(6,
 645                                        /* teardown */
 646                                        "ldr %[len], %[rseq_scratch2]\n\t"
 647                                        "ldr %[dst], %[rseq_scratch1]\n\t"
 648                                        "ldr %[src], %[rseq_scratch0]\n\t",
 649                                        error1)
 650                RSEQ_ASM_DEFINE_CMPFAIL(7,
 651                                        /* teardown */
 652                                        "ldr %[len], %[rseq_scratch2]\n\t"
 653                                        "ldr %[dst], %[rseq_scratch1]\n\t"
 654                                        "ldr %[src], %[rseq_scratch0]\n\t",
 655                                        error2)
 656#endif
 657                "8:\n\t"
 658                : /* gcc asm goto does not allow outputs */
 659                : [cpu_id]              "r" (cpu),
 660                  [current_cpu_id]      "m" (__rseq_abi.cpu_id),
 661                  [rseq_cs]             "m" (__rseq_abi.rseq_cs),
 662                  /* final store input */
 663                  [v]                   "m" (*v),
 664                  [expect]              "r" (expect),
 665                  [newv]                "r" (newv),
 666                  /* try memcpy input */
 667                  [dst]                 "r" (dst),
 668                  [src]                 "r" (src),
 669                  [len]                 "r" (len),
 670                  [rseq_scratch0]       "m" (rseq_scratch[0]),
 671                  [rseq_scratch1]       "m" (rseq_scratch[1]),
 672                  [rseq_scratch2]       "m" (rseq_scratch[2])
 673                  RSEQ_INJECT_INPUT
 674                : "r0", "memory", "cc"
 675                  RSEQ_INJECT_CLOBBER
 676                : abort, cmpfail
 677#ifdef RSEQ_COMPARE_TWICE
 678                  , error1, error2
 679#endif
 680        );
 681        rseq_workaround_gcc_asm_size_guess();
 682        return 0;
 683abort:
 684        rseq_workaround_gcc_asm_size_guess();
 685        RSEQ_INJECT_FAILED
 686        return -1;
 687cmpfail:
 688        rseq_workaround_gcc_asm_size_guess();
 689        return 1;
 690#ifdef RSEQ_COMPARE_TWICE
 691error1:
 692        rseq_workaround_gcc_asm_size_guess();
 693        rseq_bug("cpu_id comparison failed");
 694error2:
 695        rseq_workaround_gcc_asm_size_guess();
 696        rseq_bug("expected value comparison failed");
 697#endif
 698}
 699
 700static inline __attribute__((always_inline))
 701int rseq_cmpeqv_trymemcpy_storev_release(intptr_t *v, intptr_t expect,
 702                                         void *dst, void *src, size_t len,
 703                                         intptr_t newv, int cpu)
 704{
 705        uint32_t rseq_scratch[3];
 706
 707        RSEQ_INJECT_C(9)
 708
 709        rseq_workaround_gcc_asm_size_guess();
 710        __asm__ __volatile__ goto (
 711                RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */
 712                RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
 713#ifdef RSEQ_COMPARE_TWICE
 714                RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
 715                RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
 716#endif
 717                "str %[src], %[rseq_scratch0]\n\t"
 718                "str %[dst], %[rseq_scratch1]\n\t"
 719                "str %[len], %[rseq_scratch2]\n\t"
 720                /* Start rseq by storing table entry pointer into rseq_cs. */
 721                RSEQ_ASM_STORE_RSEQ_CS(1, 3f, rseq_cs)
 722                RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
 723                RSEQ_INJECT_ASM(3)
 724                "ldr r0, %[v]\n\t"
 725                "cmp %[expect], r0\n\t"
 726                "bne 5f\n\t"
 727                RSEQ_INJECT_ASM(4)
 728#ifdef RSEQ_COMPARE_TWICE
 729                RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 6f)
 730                "ldr r0, %[v]\n\t"
 731                "cmp %[expect], r0\n\t"
 732                "bne 7f\n\t"
 733#endif
 734                /* try memcpy */
 735                "cmp %[len], #0\n\t" \
 736                "beq 333f\n\t" \
 737                "222:\n\t" \
 738                "ldrb %%r0, [%[src]]\n\t" \
 739                "strb %%r0, [%[dst]]\n\t" \
 740                "adds %[src], #1\n\t" \
 741                "adds %[dst], #1\n\t" \
 742                "subs %[len], #1\n\t" \
 743                "bne 222b\n\t" \
 744                "333:\n\t" \
 745                RSEQ_INJECT_ASM(5)
 746                "dmb\n\t"       /* full mb provides store-release */
 747                /* final store */
 748                "str %[newv], %[v]\n\t"
 749                "2:\n\t"
 750                RSEQ_INJECT_ASM(6)
 751                /* teardown */
 752                "ldr %[len], %[rseq_scratch2]\n\t"
 753                "ldr %[dst], %[rseq_scratch1]\n\t"
 754                "ldr %[src], %[rseq_scratch0]\n\t"
 755                "b 8f\n\t"
 756                RSEQ_ASM_DEFINE_ABORT(3, 4,
 757                                      /* teardown */
 758                                      "ldr %[len], %[rseq_scratch2]\n\t"
 759                                      "ldr %[dst], %[rseq_scratch1]\n\t"
 760                                      "ldr %[src], %[rseq_scratch0]\n\t",
 761                                      abort, 1b, 2b, 4f)
 762                RSEQ_ASM_DEFINE_CMPFAIL(5,
 763                                        /* teardown */
 764                                        "ldr %[len], %[rseq_scratch2]\n\t"
 765                                        "ldr %[dst], %[rseq_scratch1]\n\t"
 766                                        "ldr %[src], %[rseq_scratch0]\n\t",
 767                                        cmpfail)
 768#ifdef RSEQ_COMPARE_TWICE
 769                RSEQ_ASM_DEFINE_CMPFAIL(6,
 770                                        /* teardown */
 771                                        "ldr %[len], %[rseq_scratch2]\n\t"
 772                                        "ldr %[dst], %[rseq_scratch1]\n\t"
 773                                        "ldr %[src], %[rseq_scratch0]\n\t",
 774                                        error1)
 775                RSEQ_ASM_DEFINE_CMPFAIL(7,
 776                                        /* teardown */
 777                                        "ldr %[len], %[rseq_scratch2]\n\t"
 778                                        "ldr %[dst], %[rseq_scratch1]\n\t"
 779                                        "ldr %[src], %[rseq_scratch0]\n\t",
 780                                        error2)
 781#endif
 782                "8:\n\t"
 783                : /* gcc asm goto does not allow outputs */
 784                : [cpu_id]              "r" (cpu),
 785                  [current_cpu_id]      "m" (__rseq_abi.cpu_id),
 786                  [rseq_cs]             "m" (__rseq_abi.rseq_cs),
 787                  /* final store input */
 788                  [v]                   "m" (*v),
 789                  [expect]              "r" (expect),
 790                  [newv]                "r" (newv),
 791                  /* try memcpy input */
 792                  [dst]                 "r" (dst),
 793                  [src]                 "r" (src),
 794                  [len]                 "r" (len),
 795                  [rseq_scratch0]       "m" (rseq_scratch[0]),
 796                  [rseq_scratch1]       "m" (rseq_scratch[1]),
 797                  [rseq_scratch2]       "m" (rseq_scratch[2])
 798                  RSEQ_INJECT_INPUT
 799                : "r0", "memory", "cc"
 800                  RSEQ_INJECT_CLOBBER
 801                : abort, cmpfail
 802#ifdef RSEQ_COMPARE_TWICE
 803                  , error1, error2
 804#endif
 805        );
 806        rseq_workaround_gcc_asm_size_guess();
 807        return 0;
 808abort:
 809        rseq_workaround_gcc_asm_size_guess();
 810        RSEQ_INJECT_FAILED
 811        return -1;
 812cmpfail:
 813        rseq_workaround_gcc_asm_size_guess();
 814        return 1;
 815#ifdef RSEQ_COMPARE_TWICE
 816error1:
 817        rseq_workaround_gcc_asm_size_guess();
 818        rseq_bug("cpu_id comparison failed");
 819error2:
 820        rseq_workaround_gcc_asm_size_guess();
 821        rseq_bug("expected value comparison failed");
 822#endif
 823}
 824
 825#endif /* !RSEQ_SKIP_FASTPATH */
 826