lunaix-os/arch/i386/hart.c

   1 #include <lunaix/process.h>
   2 #include <lunaix/hart_state.h>
   3 #include <lunaix/mm/vmm.h>
   4 #include <klibc/string.h>
   5
   6 #include <sys/mm/mempart.h>
   7 #include <sys/abi.h>
   8
   9 volatile struct x86_tss _tss = { .link = 0,
  10                                  .esp0 = 0,
  11                                  .ss0 = KDATA_SEG };
  12
  13 bool
  14 install_hart_transition(ptr_t vm_mnt, struct hart_transition* ht)
  15 {
  16     pte_t pte;
  17     if (!vmm_lookupat(vm_mnt, ht->inject, &pte)) {
  18         return false;
  19     }
  20
  21     mount_page(PG_MOUNT_4, pte_paddr(pte));
  22
  23     ptr_t mount_inject = PG_MOUNT_4 + va_offset(ht->inject);
  24     memcpy((void*)mount_inject, &ht->transfer, sizeof(ht->transfer));
  25
  26     unmount_page(PG_MOUNT_4);
  27     return true;
  28 }
  29
  30 void
  31 hart_prepare_transition(struct hart_transition* ht,
  32                       ptr_t kstack_tp, ptr_t ustack_pt,
  33                       ptr_t entry, bool to_user)
  34 {
  35     ptr_t offset = (ptr_t)&ht->transfer.eret - (ptr_t)&ht->transfer;
  36     ht->inject = align_stack(kstack_tp - sizeof(ht->transfer));
  37
  38     ht->transfer.state = (struct hart_state){
  39                             .registers = {
  40                                 .ds = KDATA_SEG,
  41                                 .es = KDATA_SEG,
  42                                 .fs = KDATA_SEG,
  43                                 .gs = KDATA_SEG
  44                             },
  45                             .execp = (struct exec_param*)(ht->inject + offset)
  46                         };
  47
  48     int code_seg = KCODE_SEG, data_seg = KDATA_SEG;
  49     int mstate = cpu_ldstate();
  50     if (to_user) {
  51         code_seg = UCODE_SEG, data_seg = UDATA_SEG;
  52         mstate |= 0x200;   // enable interrupt
  53     }
  54
  55     ht->transfer.eret = (struct exec_param) {
  56                             .cs = code_seg, .eip = entry,
  57                             .ss = data_seg, .esp = align_stack(ustack_pt),
  58                             .eflags = mstate
  59                         };
  60 }