include/lttng/ust-sigbus.h

   1 // SPDX-FileCopyrightText: 2020 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   2 //
   3 // SPDX-License-Identifier: GPL-2.0-only
   4
   5 #ifndef _LTTNG_UST_SIGBUS_H
   6 #define _LTTNG_UST_SIGBUS_H
   7
   8 #include <urcu/list.h>
   9 #include <setjmp.h>
  10
  11 struct lttng_ust_sigbus_range {
  12         void *start;    /* inclusive */
  13         void *end;      /* exclusive */
  14         struct cds_list_head node;
  15 };
  16
  17 struct lttng_ust_sigbus_state {
  18         int jmp_ready;
  19         struct cds_list_head head;      /* struct lttng_ust_sigbus_range */
  20         sigjmp_buf sj_env;
  21 };
  22
  23 /*
  24  * Define the lttng_ust_sigbus_state TLS variable as initial-exec model
  25  * to allow using it from the SIGBUS signal handler. This variable must
  26  * be defined by the executable using DEFINE_LTTNG_UST_SIGBUS_STATE()
  27  * rather than internally within liblttng-ust-ctl.so to ensure we don't
  28  * contribute to reach glibc limits of pre-allocated TLS IE model space
  29  * for shared objects.
  30  */
  31 #define DEFINE_LTTNG_UST_SIGBUS_STATE() \
  32         __thread __attribute__((tls_model("initial-exec"))) struct lttng_ust_sigbus_state lttng_ust_sigbus_state
  33
  34 extern __thread __attribute__((tls_model("initial-exec"))) struct lttng_ust_sigbus_state lttng_ust_sigbus_state;
  35
  36 #endif /* _LTTNG_UST_SIGBUS_H */