source: rtems/cpukit/libmisc/stackchk/check.c @ 8bb9d41

/**
 * @file
 *
 * @brief Stack Overflow Check User Extension Set
 * @ingroup libmisc_stackchk Stack Checker Mechanism
 *
 * NOTE:  This extension set automatically determines at
 *         initialization time whether the stack for this
 *         CPU grows up or down and installs the correct
 *         extension routines for that direction.
 */

/*
 *  COPYRIGHT (c) 1989-2010.
 *  On-Line Applications Research Corporation (OAR).
 *
 *  The license and distribution terms for this file may be
 *  found in the file LICENSE in this distribution or at
 *  http://www.rtems.org/license/LICENSE.
 *
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <rtems.h>
#include <inttypes.h>

/*
 * The stack dump information may be printed by a "fatal" extension.
 * Fatal extensions only get called via rtems_fatal_error_occurred()
 * and not when rtems_shutdown_executive() is called.
 * When that happens, this #define should be deleted and all the code
 * it marks.
 */
#define DONT_USE_FATAL_EXTENSION

#include <string.h>
#include <stdlib.h>

#include <rtems/bspIo.h>
#include <rtems/printer.h>
#include <rtems/stackchk.h>
#include <rtems/score/percpu.h>

/*
 *  This structure is used to fill in and compare the "end of stack"
 *  marker pattern.
 *  pattern area must be a multiple of 4 words.
 */

#if !defined(CPU_STACK_CHECK_PATTERN_INITIALIZER)
#define CPU_STACK_CHECK_PATTERN_INITIALIZER \
  { \
    0xFEEDF00D, 0x0BAD0D06, /* FEED FOOD to  BAD DOG */ \
    0xDEADF00D, 0x600D0D06  /* DEAD FOOD but GOOD DOG */ \
  }
#endif

/*
 *  The pattern used to fill the entire stack.
 */

#define BYTE_PATTERN 0xA5
#define U32_PATTERN 0xA5A5A5A5

/*
 *  Variable to indicate when the stack checker has been initialized.
 */
static int   Stack_check_Initialized = 0;

/*
 *  The "magic pattern" used to mark the end of the stack.
 */
static const uint32_t Stack_check_Pattern[] =
  CPU_STACK_CHECK_PATTERN_INITIALIZER;

#define PATTERN_SIZE_BYTES sizeof(Stack_check_Pattern)

#define PATTERN_SIZE_WORDS RTEMS_ARRAY_SIZE(Stack_check_Pattern)

/*
 * Helper function to report if the actual stack pointer is in range.
 *
 * NOTE: This uses a GCC specific method.
 */
static inline bool Stack_check_Frame_pointer_in_range(
  const Thread_Control *the_thread
)
{
  #if defined(__GNUC__)
    void *sp = __builtin_frame_address(0);
    const Stack_Control *the_stack = &the_thread->Start.Initial_stack;

    if ( sp < the_stack->area ) {
      return false;
    }
    if ( sp > (the_stack->area + the_stack->size) ) {
      return false;
    }
  #else
    #error "How do I check stack bounds on a non-GNU compiler?"
  #endif
  return true;
}

/*
 *  Where the pattern goes in the stack area is dependent upon
 *  whether the stack grow to the high or low area of the memory.
 */
#if (CPU_STACK_GROWS_UP == TRUE)
  #define Stack_check_Get_pattern( _the_stack ) \
    ((char *)(_the_stack)->area + \
         (_the_stack)->size - PATTERN_SIZE_BYTES )

  #define Stack_check_Calculate_used( _low, _size, _high_water ) \
      ((char *)(_high_water) - (char *)(_low))

  #define Stack_check_usable_stack_start(_the_stack) \
    ((_the_stack)->area)

#else
  /*
   * We need this magic offset because during a task delete the task stack will
   * be freed before we enter the task switch extension which checks the stack.
   * The task stack free operation will write the next and previous pointers
   * for the free list into this area.
   */
  #define Stack_check_Get_pattern( _the_stack ) \
    ((char *)(_the_stack)->area + sizeof(Heap_Block) - HEAP_BLOCK_HEADER_SIZE)

  #define Stack_check_Calculate_used( _low, _size, _high_water) \
      ( ((char *)(_low) + (_size)) - (char *)(_high_water) )

  #define Stack_check_usable_stack_start(_the_stack) \
      ((char *)(_the_stack)->area + PATTERN_SIZE_BYTES)

#endif

/*
 *  The assumption is that if the pattern gets overwritten, the task
 *  is too close.  This defines the usable stack memory.
 */
#define Stack_check_usable_stack_size(_the_stack) \
    ((_the_stack)->size - PATTERN_SIZE_BYTES)

#if (CPU_ALLOCATE_INTERRUPT_STACK == TRUE)
  /*
   *  Did RTEMS allocate the interrupt stack? If so, put it in
   *  Stack_Control format.
   */
  Stack_Control Stack_check_Interrupt_stack;
#endif

/*
 *  Fill an entire stack area with BYTE_PATTERN.  This will be used
 *  to check for amount of actual stack used.
 */
#define Stack_check_Dope_stack(_stack) \
  memset((_stack)->area, BYTE_PATTERN, (_stack)->size)

/*
 *  Stack_check_Initialize
 */
static void Stack_check_Initialize( void )
{
  if ( Stack_check_Initialized )
    return;

  /*
   * If appropriate, setup the interrupt stack for high water testing
   * also.
   */
  #if (CPU_ALLOCATE_INTERRUPT_STACK == TRUE)
    if (_CPU_Interrupt_stack_low && _CPU_Interrupt_stack_high) {
      Stack_check_Interrupt_stack.area = _CPU_Interrupt_stack_low;
      Stack_check_Interrupt_stack.size = (char *) _CPU_Interrupt_stack_high -
                                  (char *) _CPU_Interrupt_stack_low;
      Stack_check_Dope_stack(&Stack_check_Interrupt_stack);
   }
  #endif

  Stack_check_Initialized = 1;
}

static bool Stack_check_Is_pattern_valid(const Thread_Control *the_thread)
{
  return memcmp(
    Stack_check_Get_pattern(&the_thread->Start.Initial_stack),
    Stack_check_Pattern,
    PATTERN_SIZE_BYTES
  ) == 0;
}

/*
 *  rtems_stack_checker_create_extension
 */
bool rtems_stack_checker_create_extension(
  Thread_Control *running RTEMS_UNUSED,
  Thread_Control *the_thread
)
{
  Stack_check_Initialize();

  if (the_thread)
    Stack_check_Dope_stack(&the_thread->Start.Initial_stack);

  return true;
}

/*
 *  rtems_stack_checker_Begin_extension
 */
void rtems_stack_checker_begin_extension(
  Thread_Control *the_thread
)
{
  if ( the_thread->Object.id == 0 )        /* skip system tasks */
    return;

  memcpy(
    Stack_check_Get_pattern(&the_thread->Start.Initial_stack),
    Stack_check_Pattern,
    PATTERN_SIZE_BYTES
  );
}

/*
 *  Stack_check_report_blown_task
 *
 *  Report a blown stack.  Needs to be a separate routine
 *  so that interrupt handlers can use this too.
 *
 *  NOTE: The system is in a questionable state... we may not get
 *        the following message out.
 */
static void Stack_check_report_blown_task(
  const Thread_Control *running,
  bool pattern_ok
)
{
  const Stack_Control *stack = &running->Start.Initial_stack;
  void                *pattern_area = Stack_check_Get_pattern(stack);
  char                 name[32];

  printk("BLOWN STACK!!!\n");
  printk("task control block: 0x%08" PRIxPTR "\n", (intptr_t) running);
  printk("task ID: 0x%08lx\n", (unsigned long) running->Object.id);
  printk(
    "task name: 0x%08" PRIx32 "\n",
    running->Object.name.name_u32
  );
  printk(
    "task name string: %s\n",
    rtems_object_get_name(running->Object.id, sizeof(name), name)
  );
  printk(
    "task stack area (%lu Bytes): 0x%08" PRIxPTR " .. 0x%08" PRIxPTR "\n",
    (unsigned long) stack->size,
    (intptr_t) stack->area,
    (intptr_t) ((char *) stack->area + stack->size)
  );
  if (!pattern_ok) {
    printk(
      "damaged pattern area (%lu Bytes): 0x%08" PRIxPTR " .. 0x%08" PRIxPTR "\n",
      (unsigned long) PATTERN_SIZE_BYTES,
      (intptr_t) pattern_area,
      (intptr_t) (pattern_area + PATTERN_SIZE_BYTES)
    );
  }

  #if defined(RTEMS_MULTIPROCESSING)
    if (rtems_configuration_get_user_multiprocessing_table()) {
      printk(
        "node: 0x%08" PRIxPTR "\n",
          (intptr_t) rtems_configuration_get_user_multiprocessing_table()->node
      );
    }
  #endif

  rtems_fatal(
    RTEMS_FATAL_SOURCE_STACK_CHECKER,
    running->Object.name.name_u32
  );
}

/*
 *  rtems_stack_checker_switch_extension
 */
void rtems_stack_checker_switch_extension(
  Thread_Control *running RTEMS_UNUSED,
  Thread_Control *heir RTEMS_UNUSED
)
{
  bool sp_ok;
  bool pattern_ok;

  /*
   *  Check for an out of bounds stack pointer or an overwrite
   */
  sp_ok = Stack_check_Frame_pointer_in_range( running );

  pattern_ok = Stack_check_Is_pattern_valid( running );

  if ( !sp_ok || !pattern_ok ) {
    Stack_check_report_blown_task( running, pattern_ok );
  }
}

/*
 *  Check if blown
 */
bool rtems_stack_checker_is_blown( void )
{
  rtems_stack_checker_switch_extension( _Thread_Get_executing(), NULL );

  /*
   * The Stack Pointer and the Pattern Area are OK so return false.
   */
  return false;
}

/*
 * Stack_check_find_high_water_mark
 */
static inline void *Stack_check_find_high_water_mark(
  const void *s,
  size_t      n
)
{
  const uint32_t   *base, *ebase;
  uint32_t   length;

  base = s;
  length = n/4;

  #if ( CPU_STACK_GROWS_UP == TRUE )
    /*
     * start at higher memory and find first word that does not
     * match pattern
     */

    base += length - 1;
    for (ebase = s; base > ebase; base--)
      if (*base != U32_PATTERN)
        return (void *) base;
  #else
    /*
     * start at lower memory and find first word that does not
     * match pattern
     */

    base += PATTERN_SIZE_WORDS;
    for (ebase = base + length; base < ebase; base++)
      if (*base != U32_PATTERN)
        return (void *) base;
  #endif

  return (void *)0;
}

/*
 *  Stack_check_Dump_threads_usage
 *
 *  Try to print out how much stack was actually used by the task.
 */
static const rtems_printer* printer;

static void Stack_check_Dump_threads_usage(
  Thread_Control *the_thread
)
{
  uint32_t        size, used;
  void           *low;
  void           *high_water_mark;
  void           *current;
  Stack_Control  *stack;
  char            name[5];

  /*
   *  The pointer passed in for the_thread is guaranteed to be non-NULL from
   *  rtems_iterate_over_all_threads() so no need to check it here.
   */

  /*
   *  Obtain interrupt stack information
   */
  #if (CPU_ALLOCATE_INTERRUPT_STACK == TRUE)
    if (the_thread == (Thread_Control *) -1) {
      if (!Stack_check_Interrupt_stack.area)
        return;
      stack = &Stack_check_Interrupt_stack;
      the_thread = 0;
      current = 0;
    } else
  #endif
    {
      stack  = &the_thread->Start.Initial_stack;
      current = (void *)_CPU_Context_Get_SP( &the_thread->Registers );
    }

  low  = Stack_check_usable_stack_start(stack);
  size = Stack_check_usable_stack_size(stack);

  high_water_mark = Stack_check_find_high_water_mark(low, size);

  if ( high_water_mark )
    used = Stack_check_Calculate_used( low, size, high_water_mark );
  else
    used = 0;


  #if (CPU_ALLOCATE_INTERRUPT_STACK == TRUE)
    if ( the_thread )
  #endif
    {
      rtems_printf(
        printer,
        "0x%08" PRIx32 "  %4s",
        the_thread->Object.id,
        rtems_object_get_name( the_thread->Object.id, sizeof(name), name )
      );
    }
    #if (CPU_ALLOCATE_INTERRUPT_STACK == TRUE)
      else {
        rtems_printf( printer, "0x%08x  INTR", ~0 );
      }
    #endif

  rtems_printf(
    printer,
    " %p - %p %p  %8" PRId32 "   ",
    stack->area,
    stack->area + stack->size - 1,
    current,
    size
  );

  if (Stack_check_Initialized == 0) {
    rtems_printf( printer, "Unavailable\n" );
  } else {
    rtems_printf( printer, "%8" PRId32 "\n", used );
  }


}

/*
 *  rtems_stack_checker_fatal_extension
 */
#ifndef DONT_USE_FATAL_EXTENSION
  void rtems_stack_checker_fatal_extension(
    Internal_errors_Source  source,
    bool                    is_internal,
    uint32_t                status
  )
  {
    if (status == 0)
      rtems_stack_checker_report_usage();
  }
#endif

/*
 *  rtems_stack_checker_report_usage
 */

void rtems_stack_checker_report_usage_with_plugin(
  const rtems_printer* printer_
)
{
  if ( printer != NULL || ! rtems_print_printer_valid ( printer_ ) )
    return;

  printer = printer_;

  rtems_printf( printer, "Stack usage by thread\n");
  rtems_printf( printer,
"    ID      NAME    LOW          HIGH     CURRENT     AVAILABLE     USED\n"
  );

  /* iterate over all threads and dump the usage */
  rtems_iterate_over_all_threads( Stack_check_Dump_threads_usage );

  #if (CPU_ALLOCATE_INTERRUPT_STACK == TRUE)
    /* dump interrupt stack info if any */
    Stack_check_Dump_threads_usage((Thread_Control *) -1);
  #endif

  printer = NULL;
}

void rtems_stack_checker_report_usage( void )
{
  rtems_printer printer;
  rtems_print_printer_printk(&printer);
  rtems_stack_checker_report_usage_with_plugin( &printer );
}