@c @c COPYRIGHT (c) 1996. @c On-Line Applications Research Corporation (OAR). @c All rights reserved. @c @c $Id$ @c @ifinfo @node Fatal Error Manager, Fatal Error Manager Introduction, IO_CONTROL - Special device services, Top @end ifinfo @chapter Fatal Error Manager @ifinfo @menu * Fatal Error Manager Introduction:: * Fatal Error Manager Background:: * Fatal Error Manager Operations:: * Fatal Error Manager Directives:: @end menu @end ifinfo @ifinfo @node Fatal Error Manager Introduction, Fatal Error Manager Background, Fatal Error Manager, Fatal Error Manager @end ifinfo @section Introduction The fatal error manager processes all fatal or irrecoverable errors. The directive provided by the fatal error manager is: @itemize @bullet @item @code{fatal_error_occurred} - Invoke the fatal error handler @end itemize @ifinfo @node Fatal Error Manager Background, Fatal Error Manager Operations, Fatal Error Manager Introduction, Fatal Error Manager @end ifinfo @section Background The fatal error manager is called upon detection of an irrecoverable error condition by either RTEMS or the application software. Fatal errors can be detected from three sources: @itemize @bullet @item the executive (RTEMS) @item user system code @item user application code @end itemize RTEMS automatically invokes the fatal error manager upon detection of an error it considers to be fatal. Similarly, the user should invoke the fatal error manager upon detection of a fatal error. Each status or dynamic user extension set may include a fatal error handler. The fatal error handler in the static extension set can be used to provide access to debuggers and monitors which may be present on the target hardware. If any user-supplied fatal error handlers are installed, the fatal error manager will invoke them. If no user handlers are configured or if all the user handler return control to the fatal error manager, then the RTEMS default fatal error handler is invoked. If the default fatal error handler is invoked, then the system state is marked as failed. Although the precise behavior of the default fatal error handler is processor specific, in general, it will disable all maskable interrupts, place the error code in a known processor dependent place (generally either on the stack or in a register), and halt the processor. The precise actions of the RTEMS fatal error are discussed in the Default Fatal Error Processing chapter of the Applications Supplement document for a specific target processor. @ifinfo @node Fatal Error Manager Operations, Announcing a Fatal Error, Fatal Error Manager Background, Fatal Error Manager @end ifinfo @section Operations @ifinfo @menu * Announcing a Fatal Error:: @end menu @end ifinfo @ifinfo @node Announcing a Fatal Error, Fatal Error Manager Directives, Fatal Error Manager Operations, Fatal Error Manager Operations @end ifinfo @subsection Announcing a Fatal Error The fatal_error_occurred directive is invoked when a fatal error is detected. Before invoking any user-supplied fatal error handlers or the RTEMS fatal error handler, the fatal_error_occurred directive stores useful information in the variable @code{_Internal_errors_What_happened}. This @value{STRUCTURE} contains three pieces of information: @itemize @bullet @item the source of the error (API or executive core), @item whether the error was generated internally by the executive, and a @item a numeric code to indicate the error type. @end itemize The error type indicator is dependent on the source of the error and whether or not the error was internally generated by the executive. The fatal_error_directive directive is responsible for invoking an optional user-supplied fatal error handler and/or the RTEMS fatal error handler. All fatal error handlers are passed an error code to describe the error detected. Occasionally, an application requires more sophisticated fatal error processing such as passing control to a debugger. For these cases, a user-supplied fatal error handler can be specified in the RTEMS configuration table. The User Extension Table field fatal contains the address of the fatal error handler to be executed when the fatal_error_occurred directive is called. If the field is set to NULL or if the configured fatal error handler returns to the executive, then the default handler provided by RTEMS is executed. This default handler will halt execution on the processor where the error occurred. @ifinfo @node Fatal Error Manager Directives, FATAL_ERROR_OCCURRED - Invoke the fatal error handler, Announcing a Fatal Error, Fatal Error Manager @end ifinfo @section Directives @ifinfo @menu * FATAL_ERROR_OCCURRED - Invoke the fatal error handler:: @end menu @end ifinfo This section details the fatal error manager's directives. A subsection is dedicated to each of this manager's directives and describes the calling sequence, related constants, usage, and status codes. @page @ifinfo @node FATAL_ERROR_OCCURRED - Invoke the fatal error handler, Scheduling Concepts, Fatal Error Manager Directives, Fatal Error Manager Directives @end ifinfo @subsection FATAL_ERROR_OCCURRED - Invoke the fatal error handler @subheading CALLING SEQUENCE: @ifset is-C @example void volatile rtems_fatal_error_occurred( rtems_unsigned32 the_error ); @end example @end ifset @ifset is-Ada @example procedure Fatal_Error_Occurred ( The_Error : in RTEMS.Unsigned32 ); @end example @end ifset @subheading DIRECTIVE STATUS CODES NONE @subheading DESCRIPTION: This directive processes fatal errors. If the FATAL error extension is defined in the configuration table, then the user-defined error extension is called. If configured and the provided FATAL error extension returns, then the RTEMS default error handler is invoked. This directive can be invoked by RTEMS or by the user's application code including initialization tasks, other tasks, and ISRs. @subheading NOTES: This directive supports local operations only. Unless the user-defined error extension takes special actions such as restarting the calling task, this directive WILL NOT RETURN to the caller. The user-defined extension for this directive may wish to initiate a global shutdown.