assembler programming in user space

Question

Is it possible to have a piece of code like this in user space? I mean is it possible to read/write co-processor register in user space in Netbsd / Linux?

XYZ]# cat pmc.c 

static inline int
arm11_pmc_ctrl_read(void)
{
    unsigned int val;

    __asm volatile ("mrc p15, 0, %0, c15, c12, 0" : "=r" (val));

    return val;
}
int main(){
    unsigned int ctrl;
        ctrl = arm11_pmc_ctrl_read();
}

Answer 1

User space does not have access to privileged instructions or registers. Look in your assembler manual to find out if the instructions and registers you are using are privileged.