/* kernel entry point called at the end of the boot sequence */
void __boot() {
if (current_cpu_id() == 0) {
bootparams = physical_to_virtual(0x00000000);
console_init();
mem_init();
trap_init();
keyboard_init();
set_cpu_enable(0xFFFFFFFF);
network_init_pipeline();
network_start_receive();
set_cpu_enable(0xFFFFFFFF);
}
core_start(current_cpu_id());
while (1) ;
shutdown();
}
void trap_init()
{
int id = current_cpu_id();
/* trap should use the same $gp as the current code */
trap_gp[id] = current_cpu_gp();
/* trap should use a fresh stack */
void *bottom = alloc_pages(4);
trap_stack_top[id] = bottom + 4*PAGE_SIZE - 4;
/* put the trap save-state at the top of the corresponding trap stack */
trap_stack_top[id] -= sizeof(struct mips_core_data);
trap_save_state[id] = trap_stack_top[id];
/* it is now safe to take interrupts on this core */
intr_restore(1);
}
void trap_handler(struct mips_core_data *state, unsigned int status, unsigned int cause)
{
if (debug) printf("trap_handler: status=0x%08x cause=0x%08x on core %d\n", status, cause, current_cpu_id());
// diagnose the cause of the trap
int ecode = (cause & 0x7c) >> 2;
switch (ecode) {
case ECODE_INT: /* external interrupt */
interrupt_handler(cause);
return; /* this is the only exception we currently handle; all others cause a shutdown() */
case ECODE_MOD: /* attempt to write to a non-writable page */
printf("trap_handler: some code is trying to write to a non-writable page!\n");
break;
case ECODE_TLBL: /* page fault during load or instruction fetch */
case ECODE_TLBS: /* page fault during store */
printf("trap_handler: some code is trying to access a bad virtual address!\n");
break;
case ECODE_ADDRL: /* unaligned address during load or instruction fetch */
case ECODE_ADDRS: /* unaligned address during store */
printf("trap_handler: some code is trying to access a mis-aligned address!\n");
break;
case ECODE_IBUS: /* instruction fetch bus error */
printf("trap_handler: some code is trying to execute non-RAM physical addresses!\n");
break;
case ECODE_DBUS: /* data load/store bus error */
printf("trap_handler: some code is read or write physical address that can't be!\n");
break;
case ECODE_SYSCALL: /* system call */
printf("trap_handler: who is doing a syscall? not in this project...\n");
break;
case ECODE_BKPT: /* breakpoint */
printf("trap_handler: reached breakpoint, or maybe did a divide by zero!\n");
break;
case ECODE_RI: /* reserved opcode */
printf("trap_handler: trying to execute something that isn't a valid instruction!\n");
break;
case ECODE_OVF: /* arithmetic overflow */
printf("trap_handler: some code had an arithmetic overflow!\n");
break;
case ECODE_NOEX: /* attempt to execute to a non-executable page */
printf("trap_handler: some code attempted to execute a non-executable virtual address!\n");
break;
default:
printf("trap_handler: unknown error code 0x%x\n", ecode);
break;
}
shutdown();
}
/* kernel entry point called at the end of the boot sequence */
void __boot() {
if (current_cpu_id() == 0) {
/* core 0 boots first, and does all of the initialization */
// boot parameters are on physical page 0
bootparams = physical_to_virtual(0x00000000);
// initialize console early, so output works
console_init();
// output should now work
printf("Welcome to my kernel!\n");
printf("Running on a %d-way multi-core machine\n", current_cpu_exists());
// initialize memory allocators
mem_init();
// prepare to handle interrupts, exceptions, etc.
trap_init();
// initialize keyboard late, since it isn't really used by anything else
keyboard_init();
// see which cores are already on
for (int i = 0; i < 32; i++)
printf("CPU[%d] is %s\n", i, (current_cpu_enable() & (1<<i)) ? "on" : "off");
// turn on all other cores
set_cpu_enable(0xFFFFFFFF);
// see which cores got turned on
busy_wait(0.1);
for (int i = 0; i < 32; i++)
printf("CPU[%d] is %s\n", i, (current_cpu_enable() & (1<<i)) ? "on" : "off");
} else {
/* remaining cores boot after core 0 turns them on */
// nothing to initialize here...
}
printf("Core %d of %d is alive!\n", current_cpu_id(), current_cpu_exists());
busy_wait(current_cpu_id() * 0.1); // wait a while so messages from different cores don't get so mixed up
int size = 64 * 1024 * 4;
printf("about to do calloc(%d, 1)\n", size);
unsigned int t0 = current_cpu_cycles();
calloc(size, 1);
unsigned int t1 = current_cpu_cycles();
printf("DONE (%u cycles)!\n", t1 - t0);
while (1) ;
for (int i = 1; i < 30; i++) {
int size = 1 << i;
printf("about to do calloc(%d, 1)\n", size);
calloc(size, 1);
}
while (1) {
printf("Core %d is still running...\n", current_cpu_id());
busy_wait(4.0); // wait 4 seconds
}
shutdown();
}
