sta/arm-test.c

/*
 * In order to access the breakpoint/watchpoint control registers,
 * we must be running in debug monitor mode.
 */
#define ARM_DSCR_HDBGEN (1 << 14) /* DSCR halting bits. */
#define ARM_DSCR_MDBGEN (1 << 15) /* DSCR monitor bits. */

/* Accessor macros for the debug registers. */
#define ARM_DBG_READ(N, M, OP2, VAL)                                      \
    do                                                                    \
    {                                                                     \
        asm volatile("mrc p14, 0, %0, " #N "," #M ", " #OP2 : "=r"(VAL)); \
    } while (0)

#define ARM_DBG_WRITE(N, M, OP2, VAL)                                      \
    do                                                                     \
    {                                                                      \
        asm volatile("mcr p14, 0, %0, " #N "," #M ", " #OP2 : : "r"(VAL)); \
    } while (0)

static int monitor_mode_enabled(void)
{
    unsigned int dscr;
    ARM_DBG_READ(c0, c1, 0, dscr);

    if (dscr & ARM_DSCR_MDBGEN)
        return 1;
    return 0;
}

#include <stdio.h>


int main()
{
    printf("%u\n", monitor_mode_enabled());
}