src/main/drivers/stack_check.c

   1 /*
   2  * This file is part of Cleanflight and Betaflight.
   3  *
   4  * Cleanflight and Betaflight are free software. You can redistribute
   5  * this software and/or modify this software under the terms of the
   6  * GNU General Public License as published by the Free Software
   7  * Foundation, either version 3 of the License, or (at your option)
   8  * any later version.
   9  *
  10  * Cleanflight and Betaflight are distributed in the hope that they
  11  * will be useful, but WITHOUT ANY WARRANTY; without even the implied
  12  * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  13  * See the GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this software.
  17  *
  18  * If not, see <http://www.gnu.org/licenses/>.
  19  */
  20
  21 #include <stdbool.h>
  22 #include <stdint.h>
  23 #include <string.h>
  24
  25 #include "platform.h"
  26
  27 #include "build/debug.h"
  28
  29 #include "common/utils.h"
  30
  31 #include "drivers/stack_check.h"
  32
  33 #define STACK_FILL_CHAR 0xa5
  34
  35 extern char _estack; // end of stack, declared in .LD file
  36 extern char _Min_Stack_Size; // declared in .LD file
  37
  38 /*
  39  * The ARM processor uses a full descending stack. This means the stack pointer holds the address
  40  * of the last stacked item in memory. When the processor pushes a new item onto the stack,
  41  * it decrements the stack pointer and then writes the item to the new memory location.
  42  *
  43  *
  44  * RAM layout is generally as below, although some targets vary
  45  *
  46  * F1 Boards
  47  * RAM is origin 0x20000000 length 20K that is:
  48  * 0x20000000 to 0x20005000
  49  *
  50  * F3 Boards
  51  * RAM is origin 0x20000000 length 40K that is:
  52  * 0x20000000 to 0x2000a000
  53  *
  54  * F4 Boards
  55  * RAM is origin 0x20000000 length 128K that is:
  56  * 0x20000000 to 0x20020000
  57  *
  58  * See the linker scripts for actual stack configuration.
  59  */
  60
  61 #ifdef USE_STACK_CHECK
  62
  63 static uint32_t usedStackSize;
  64
  65 void taskStackCheck(timeUs_t currentTimeUs)
  66 {
  67     UNUSED(currentTimeUs);
  68
  69     char * const stackHighMem = &_estack;
  70     const uint32_t stackSize = (uint32_t)&_Min_Stack_Size;
  71     char * const stackLowMem = stackHighMem - stackSize;
  72     const char * const stackCurrent = (char *)&stackLowMem;
  73
  74     char *p;
  75     for (p = stackLowMem; p < stackCurrent; ++p) {
  76         if (*p != STACK_FILL_CHAR) {
  77             break;
  78         }
  79     }
  80
  81     usedStackSize = (uint32_t)stackHighMem - (uint32_t)p;
  82
  83     DEBUG_SET(DEBUG_STACK, 0, (uint32_t)stackHighMem & 0xffff);
  84     DEBUG_SET(DEBUG_STACK, 1, (uint32_t)stackLowMem & 0xffff);
  85     DEBUG_SET(DEBUG_STACK, 2, (uint32_t)stackCurrent & 0xffff);
  86     DEBUG_SET(DEBUG_STACK, 3, (uint32_t)p & 0xffff);
  87 }
  88
  89 uint32_t stackUsedSize(void)
  90 {
  91     return usedStackSize;
  92 }
  93 #endif
  94
  95 uint32_t stackTotalSize(void)
  96 {
  97     return (uint32_t)(intptr_t)&_Min_Stack_Size;
  98 }
  99
 100 uint32_t stackHighMem(void)
 101 {
 102     return (uint32_t)(intptr_t)&_estack;
 103 }