void isr_exn_ud_bottom(struct x86_exregs *regs)
{
/* see if it's a LOCK NOP. (this is why the "syscall" is so slow.) */
/* NOTE: could extend the kernel data segment to the full address space,
* and wrap the user-space pointer. that'd remove the farting around with
* the mapping database, page tables, and supervisor space.
*/
struct thread *current = get_current_thread();
uint8_t buf[2];
size_t n = space_memcpy_from(current->space, buf, regs->eip, 2);
if(n < 2) {
panic("can't read from #UD eip? what.");
}
if(buf[0] == 0xf0 && buf[1] == 0x90) {
/* it is L4_KernelInterface().
* TODO: proper values
*/
regs->eip += 2;
regs->eax = L4_Address(current->space->kip_area);
/* TODO: replace these with proper KIP accessors */
regs->ecx = *(L4_Word_t *)(kip_mem + 0x04); /* API VERSION */
regs->edx = *(L4_Word_t *)(kip_mem + 0x08); /* API FLAGS */
/* id = 23 (because 2 + 3 = 5); subid = 17
* TODO: get proper values at some point.
*/
regs->esi = (23 << 24) | (17 << 16); /* KERNEL ID */
} else {
printf("#UD at eip 0x%lx, esp 0x%lx\n", regs->eip, regs->esp);
/* TODO: pop an "invalid opcode" exception. */
thread_halt(current);
assert(current->status == TS_STOPPED);
return_to_scheduler();
}
}
static void
thread_entry(void) {
cur_tc->tc_entry(cur_tc->tc_arg);
thread_halt();
}