sysdeps/unix/sysv/linux/tst-rseq.h

   1 /* Restartable Sequences tests header.
   2    Copyright (C) 2021-2023 Free Software Foundation, Inc.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <https://www.gnu.org/licenses/>.  */
  17
  18 #include <errno.h>
  19 #include <error.h>
  20 #include <stdbool.h>
  21 #include <stdint.h>
  22 #include <support/check.h>
  23 #include <syscall.h>
  24 #include <sys/rseq.h>
  25 #include <tls.h>
  26
  27 static inline bool
  28 rseq_thread_registered (void)
  29 {
  30   return THREAD_GETMEM_VOLATILE (THREAD_SELF, rseq_area.cpu_id) >= 0;
  31 }
  32
  33 static inline int
  34 sys_rseq (struct rseq *rseq_abi, uint32_t rseq_len, int flags, uint32_t sig)
  35 {
  36   return syscall (__NR_rseq, rseq_abi, rseq_len, flags, sig);
  37 }
  38
  39 static inline bool
  40 rseq_available (void)
  41 {
  42   int rc;
  43
  44   rc = sys_rseq (NULL, 0, 0, 0);
  45   if (rc != -1)
  46     FAIL_EXIT1 ("Unexpected rseq return value %d", rc);
  47   switch (errno)
  48     {
  49     case ENOSYS:
  50       return false;
  51     case EINVAL:
  52       /* rseq is implemented, but detected an invalid rseq_len parameter.  */
  53       return true;
  54     default:
  55       FAIL_EXIT1 ("Unexpected rseq error %s", strerror (errno));
  56     }
  57 }