cpu.h

void
switch_to_process(process_t *proc)
{
	/* Set the entry point in MEPC */
	asm volatile("csrw mepc, %0" ::"r"(proc->entrypoint));

	asm volatile("mv ra, %0" ::"r"(proc->regf->ra));
	asm volatile("mv sp, %0" ::"r"(proc->regf->sp));
	asm volatile("mv a0, %0" ::"r"(proc));

	asm volatile("mret");
}

supervisor.c

.....	
  if (!(kcontext->user_context = malloc(sizeof(uctxt_t *)))) {
		log_fatal("Error allocating memory for user context");
	}

	kcontext->user_context->regf = create_regf(1000);
	kcontext->user_context->total_procs = 0;

	_init_timer_intrp(kcontext);

	log_info("Droping to user-mode");
	drop_to_mode(
	    PRIVILEGE_USER, kcontext->user_context, user_mode_entrypoint);
}

timer.c

void
kexcep_timer_handler(int id, void *data)
{
	kctxt_t *kcontext = (kctxt_t *)data;

	disable_timer(kcontext->timer_intrid);

	sched(kcontext, kcontext->user_context->total_procs);

	metal_cpu_set_mtimecmp(
	    kcontext->cpu, metal_cpu_get_mtime(kcontext->cpu) + RTC_FREQ);

	log_warn(
	    "[kexcep_timer_handler] | Exception | Timer interrupt %p | id %d | mtime %ld | timebase %ld",
	    kcontext->timer_intr, id, metal_cpu_get_mtime(kcontext->cpu),
	    metal_cpu_get_timebase(kcontext->cpu));

	enable_timer(kcontext->timer_intrid);
	// return_from_excp(kctxt->cpu, id);
}

user.c

void
process_a(void *data)
{
	for (;;) {
		printf("Hello, from Process A");
	}
}