include/lttng/ust-sigbus.h

   1 /*
   2  * Copyright (C) 2020 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; version 2 of the License only.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along
  14  * with this program; if not, write to the Free Software Foundation, Inc.,
  15  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  16  */
  17
  18 #ifndef _LTTNG_UST_SIGBUS_H
  19 #define _LTTNG_UST_SIGBUS_H
  20
  21 #include <urcu/list.h>
  22 #include <setjmp.h>
  23
  24 struct lttng_ust_sigbus_range {
  25         void *start;    /* inclusive */
  26         void *end;      /* exclusive */
  27         struct cds_list_head node;
  28 };
  29
  30 struct lttng_ust_sigbus_state {
  31         int jmp_ready;
  32         struct cds_list_head head;      /* struct lttng_ust_sigbus_range */
  33         sigjmp_buf sj_env;
  34 };
  35
  36 /*
  37  * Define the lttng_ust_sigbus_state TLS variable as initial-exec model
  38  * to allow using it from the SIGBUS signal handler. This variable must
  39  * be defined by the executable using DEFINE_LTTNG_UST_SIGBUS_STATE()
  40  * rather than internally within liblttng-ust-ctl.so to ensure we don't
  41  * contribute to reach glibc limits of pre-allocated TLS IE model space
  42  * for shared objects.
  43  */
  44 #define DEFINE_LTTNG_UST_SIGBUS_STATE() \
  45         __thread __attribute__((tls_model("initial-exec"))) struct lttng_ust_sigbus_state lttng_ust_sigbus_state
  46
  47 extern __thread __attribute__((tls_model("initial-exec"))) struct lttng_ust_sigbus_state lttng_ust_sigbus_state;
  48
  49 #endif /* _LTTNG_UST_SIGBUS_H */