To trigger something on other CPU's, platforms use IPI's.
The logic to do this on arm is defined in, smp_send_all_cpu_backtrace()
-> file - kernel/arch/arm/kernel/smp.c
This sends IPI to all the cpu's to dump the stack. If you want to use it in your code, use the platform independent wrapper arch_trigger_all_cpu_backtrace() by including asm/irq.h
#include <asm/irq.h>
void dump_all_cpu_stack(void)
{
arch_trigger_all_cpu_backtrace();
}