src/main/drivers/stack_check.c

   1 /*
   2  * stack_check.c
   3  *
   4  *  Created on: 23 Aug 2016
   5  *      Author: martinbudden
   6  */
   7
   8 #include <stdbool.h>
   9 #include <stdint.h>
  10 #include <string.h>
  11
  12 #include "platform.h"
  13
  14 #include "build/build_config.h"
  15 #include "build/debug.h"
  16
  17 #define STACK_FILL_CHAR 0xa5
  18
  19 extern char _estack; // end of stack, declared in .LD file
  20 extern char _Min_Stack_Size; // declared in .LD file
  21
  22 /*
  23  * The ARM processor uses a full descending stack. This means the stack pointer holds the address
  24  * of the last stacked item in memory. When the processor pushes a new item onto the stack,
  25  * it decrements the stack pointer and then writes the item to the new memory location.
  26  *
  27  *
  28  * RAM layout is generally as below, although some targets vary
  29  *
  30  * F1 Boards
  31  * RAM is origin 0x20000000 length 20K that is:
  32  * 0x20000000 to 0x20005000
  33  *
  34  * F3 Boards
  35  * RAM is origin 0x20000000 length 40K that is:
  36  * 0x20000000 to 0x2000a000
  37  *
  38  * F4 Boards
  39  * RAM is origin 0x20000000 length 128K that is:
  40  * 0x20000000 to 0x20020000
  41  *
  42  */
  43
  44 #ifdef STACK_CHECK
  45
  46 static uint32_t usedStackSize;
  47
  48 void taskStackCheck(timeUs_t currentTimeUs)
  49 {
  50     (void)currentTimeUs;
  51
  52     char * const stackHighMem = &_estack;
  53     const uint32_t stackSize = (uint32_t)&_Min_Stack_Size;
  54     char * const stackLowMem = stackHighMem - stackSize;
  55     const char * const stackCurrent = (char *)&stackLowMem;
  56
  57     char *p;
  58     for (p = stackLowMem; p < stackCurrent; ++p) {
  59         if (*p != STACK_FILL_CHAR) {
  60             break;
  61         }
  62     }
  63
  64     usedStackSize = (uint32_t)stackHighMem - (uint32_t)p;
  65
  66 #ifdef DEBUG_STACK
  67     debug[0] = (uint32_t)stackHighMem & 0xffff;
  68     debug[1] = (uint32_t)stackLowMem & 0xffff;
  69     debug[2] = (uint32_t)stackCurrent & 0xffff;
  70     debug[3] = (uint32_t)p & 0xffff;
  71 #endif
  72 }
  73
  74 uint32_t stackUsedSize(void)
  75 {
  76     return usedStackSize;
  77 }
  78 #endif
  79
  80 #if !defined(SITL_BUILD)
  81
  82 uint32_t stackTotalSize(void)
  83 {
  84     return (uint32_t)&_Min_Stack_Size;
  85 }
  86
  87 uint32_t stackHighMem(void)
  88 {
  89     return (uint32_t)&_estack;
  90 }
  91
  92 #endif