void __attribute__((naked)) sys_schedule()
{
need_resched = 0;
__asm__ __volatile__("b schedule_core");
/* it never comes back here */
schedule_finish();
__ret_from_exc(0);
}
void __attribute__((naked, optimize("O0"))) irq_handler()
{
__asm__ __volatile__("sub lr, lr, #4");
schedule_prepare();
__asm__ __volatile__("bl irq_handler_c");
/* schedule if sched_req is set */
__asm__ __volatile__(
"cmp %0, #0 \n\t"
"ldrne r12, =sys_schedule \n\t"
"blxne r12 \n\t"
:: "r"(need_resched)
: "r12", "memory");
schedule_finish();
__ret_from_exc(0);
}
int __init main()
{
/* keep the calling order below because of dependencies */
sys_init();
mm_init();
fs_init();
device_init();
systick_init();
scheduler_init();
console_init();
make_init_task();
load_user_task(); /* that are registered statically */
softirq_init();
#ifdef CONFIG_TIMER
timer_init();
#endif
#ifndef DEFSTR
#define DEFMKSTR(x) #x
#define DEFSTR(x) DEFMKSTR(x)
#endif
/* a banner */
printk("yaos %s %s\n", DEFSTR(VERSION), DEFSTR(MACHINE));
/* switch from boot stack memory to new one */
set_user_sp(init.mm.sp);
set_kernel_sp(init.mm.kernel.sp);
/* everything ready now */
#ifndef ARMv7A
sei();
#endif
resched();
/* it doesn't really reach up to this point. init task becomes idle as
* its context is already set to idle */
__context_restore(current);
__ret_from_exc(0);
freeze();
return 0;
}
void __attribute__((naked, optimize("O0"))) svc_handler()
{
schedule_prepare();
/* branch to interrupt service routine */
__asm__ __volatile__(
"mov r4, %0 \n\t"
:: "r"(current->mm.sp) : "memory");
__asm__ __volatile__(
"ldr r0, [r4, #4] \n\t"
/* if nr >= SYSCALL_NR */
"cmp r0, %0 \n\t"
/* then nr = 0 */
"movge r0, #0 \n\t"
/* get the syscall address */
"ldr r12, =syscall_table \n\t"
"ldr r12, [r12, r0, lsl #2] \n\t"
/* arguments in place */
"ldr r0, [r4, #12] \n\t"
"ldr r1, [r4, #16] \n\t"
"ldr r2, [r4, #20] \n\t"
"blx r12 \n\t"
/* r0 now holds the return value */
"str r0, [r4, #4] \n\t"
:: "I"(SYSCALL_NR) : "memory");
/* schedule if sched_req is set */
__asm__ __volatile__(
"cmp %0, #0 \n\t"
"ldrne r12, =sys_schedule \n\t"
"blxne r12 \n\t"
:: "r"(need_resched)
: "r12", "memory");
schedule_finish();
__ret_from_exc(0);
}
