Exemplo n.º 1
0
BX_CPU_C::return_protected(bxInstruction_c *i, Bit16u pop_bytes)
{
  Bit16u raw_cs_selector, raw_ss_selector;
  bx_selector_t cs_selector, ss_selector;
  bx_descriptor_t cs_descriptor, ss_descriptor;
  Bit32u stack_param_offset;
  bx_address return_RIP, return_RSP, temp_RSP;
  Bit32u dword1, dword2;

  /* + 6+N*2: SS      | +12+N*4:     SS | +24+N*8      SS */
  /* + 4+N*2: SP      | + 8+N*4:    ESP | +16+N*8     RSP */
  /*          parm N  | +        parm N | +        parm N */
  /*          parm 3  | +        parm 3 | +        parm 3 */
  /*          parm 2  | +        parm 2 | +        parm 2 */
  /* + 4:     parm 1  | + 8:     parm 1 | +16:     parm 1 */
  /* + 2:     CS      | + 4:         CS | + 8:         CS */
  /* + 0:     IP      | + 0:        EIP | + 0:        RIP */

#if BX_SUPPORT_X86_64
  if (StackAddrSize64()) temp_RSP = RSP;
  else
#endif
  {
    if (BX_CPU_THIS_PTR sregs[BX_SEG_REG_SS].cache.u.segment.d_b) temp_RSP = ESP;
    else temp_RSP = SP;
  }

#if BX_SUPPORT_X86_64
  if (i->os64L()) {
    raw_cs_selector = (Bit16u) read_virtual_qword_64(BX_SEG_REG_SS, temp_RSP + 8);
    return_RIP      =          read_virtual_qword_64(BX_SEG_REG_SS, temp_RSP);
    stack_param_offset = 16;
  }
  else
#endif
  if (i->os32L()) {
    raw_cs_selector = (Bit16u) read_virtual_dword(BX_SEG_REG_SS, temp_RSP + 4);
    return_RIP      =          read_virtual_dword(BX_SEG_REG_SS, temp_RSP);
    stack_param_offset = 8;
  }
  else {
    raw_cs_selector = read_virtual_word(BX_SEG_REG_SS, temp_RSP + 2);
    return_RIP      = read_virtual_word(BX_SEG_REG_SS, temp_RSP);
    stack_param_offset = 4;
  }

  // selector must be non-null else #GP(0)
  if ((raw_cs_selector & 0xfffc) == 0) {
    BX_ERROR(("return_protected: CS selector null"));
    exception(BX_GP_EXCEPTION, 0, 0);
  }

  parse_selector(raw_cs_selector, &cs_selector);

  // selector index must be within its descriptor table limits,
  // else #GP(selector)
  fetch_raw_descriptor(&cs_selector, &dword1, &dword2, BX_GP_EXCEPTION);

  // descriptor AR byte must indicate code segment, else #GP(selector)
  parse_descriptor(dword1, dword2, &cs_descriptor);

  // return selector RPL must be >= CPL, else #GP(return selector)
  if (cs_selector.rpl < CPL) {
    BX_ERROR(("return_protected: CS.rpl < CPL"));
    exception(BX_GP_EXCEPTION, raw_cs_selector & 0xfffc, 0);
  }

  // check code-segment descriptor
  check_cs(&cs_descriptor, raw_cs_selector, 0, cs_selector.rpl);

  // if return selector RPL == CPL then
  // RETURN TO SAME PRIVILEGE LEVEL
  if (cs_selector.rpl == CPL)
  {
    BX_DEBUG(("return_protected: return to SAME PRIVILEGE LEVEL"));

    branch_far64(&cs_selector, &cs_descriptor, return_RIP, CPL);

#if BX_SUPPORT_X86_64
    if (StackAddrSize64())
      RSP += stack_param_offset + pop_bytes;
    else
#endif
    {
      if (BX_CPU_THIS_PTR sregs[BX_SEG_REG_SS].cache.u.segment.d_b)
        RSP = ESP + stack_param_offset + pop_bytes;
      else
         SP += stack_param_offset + pop_bytes;
    }
    return;
  }
  /* RETURN TO OUTER PRIVILEGE LEVEL */
  else {
    /* + 6+N*2: SS      | +12+N*4:     SS | +24+N*8      SS */
    /* + 4+N*2: SP      | + 8+N*4:    ESP | +16+N*8     RSP */
    /*          parm N  | +        parm N | +        parm N */
    /*          parm 3  | +        parm 3 | +        parm 3 */
    /*          parm 2  | +        parm 2 | +        parm 2 */
    /* + 4:     parm 1  | + 8:     parm 1 | +16:     parm 1 */
    /* + 2:     CS      | + 4:         CS | + 8:         CS */
    /* + 0:     IP      | + 0:        EIP | + 0:        RIP */

    BX_DEBUG(("return_protected: return to OUTER PRIVILEGE LEVEL"));

#if BX_SUPPORT_X86_64
    if (i->os64L()) {
      raw_ss_selector = read_virtual_word_64 (BX_SEG_REG_SS, temp_RSP + 24 + pop_bytes);
      return_RSP      = read_virtual_qword_64(BX_SEG_REG_SS, temp_RSP + 16 + pop_bytes);
    }
    else
#endif
    if (i->os32L()) {
      raw_ss_selector = read_virtual_word (BX_SEG_REG_SS, temp_RSP + 12 + pop_bytes);
      return_RSP      = read_virtual_dword(BX_SEG_REG_SS, temp_RSP +  8 + pop_bytes);
    }
    else {
      raw_ss_selector = read_virtual_word(BX_SEG_REG_SS, temp_RSP + 6 + pop_bytes);
      return_RSP      = read_virtual_word(BX_SEG_REG_SS, temp_RSP + 4 + pop_bytes);
    }

    /* selector index must be within its descriptor table limits,
     * else #GP(selector) */
    parse_selector(raw_ss_selector, &ss_selector);

    if ((raw_ss_selector & 0xfffc) == 0) {
      if (long_mode()) {
        if (! IS_LONG64_SEGMENT(cs_descriptor) || (cs_selector.rpl == 3)) {
          BX_ERROR(("return_protected: SS selector null"));
          exception(BX_GP_EXCEPTION, 0, 0);
        }
      }
      else // not in long or compatibility mode
      {
        BX_ERROR(("return_protected: SS selector null"));
        exception(BX_GP_EXCEPTION, 0, 0);
      }
    }

    fetch_raw_descriptor(&ss_selector, &dword1, &dword2, BX_GP_EXCEPTION);
    parse_descriptor(dword1, dword2, &ss_descriptor);

    /* selector RPL must = RPL of the return CS selector,
     * else #GP(selector) */
    if (ss_selector.rpl != cs_selector.rpl) {
      BX_ERROR(("return_protected: ss.rpl != cs.rpl"));
      exception(BX_GP_EXCEPTION, raw_ss_selector & 0xfffc, 0);
    }

    /* descriptor AR byte must indicate a writable data segment,
     * else #GP(selector) */
    if (ss_descriptor.valid==0 || ss_descriptor.segment==0 ||
         IS_CODE_SEGMENT(ss_descriptor.type) ||
        !IS_DATA_SEGMENT_WRITEABLE(ss_descriptor.type))
    {
      BX_ERROR(("return_protected: SS.AR byte not writable data"));
      exception(BX_GP_EXCEPTION, raw_ss_selector & 0xfffc, 0);
    }

    /* descriptor dpl must = RPL of the return CS selector,
     * else #GP(selector) */
    if (ss_descriptor.dpl != cs_selector.rpl) {
      BX_ERROR(("return_protected: SS.dpl != cs.rpl"));
      exception(BX_GP_EXCEPTION, raw_ss_selector & 0xfffc, 0);
    }

    /* segment must be present else #SS(selector) */
    if (! IS_PRESENT(ss_descriptor)) {
      BX_ERROR(("return_protected: ss.present == 0"));
      exception(BX_SS_EXCEPTION, raw_ss_selector & 0xfffc, 0);
    }

    branch_far64(&cs_selector, &cs_descriptor, return_RIP, cs_selector.rpl);

    /* load SS:SP from stack */
    /* load SS-cache with return SS descriptor */
    load_ss(&ss_selector, &ss_descriptor, cs_selector.rpl);

#if BX_SUPPORT_X86_64
    if (StackAddrSize64())
      RSP = return_RSP + pop_bytes;
    else
#endif
    if (ss_descriptor.u.segment.d_b)
      RSP = (Bit32u) return_RSP + pop_bytes;
    else
      SP  = (Bit16u) return_RSP + pop_bytes;

    /* check ES, DS, FS, GS for validity */
    validate_seg_regs();
  }
}
Exemplo n.º 2
0
void BX_CPU_C::long_mode_int(Bit8u vector, unsigned soft_int, bx_bool push_error, Bit16u error_code)
{
  bx_descriptor_t gate_descriptor, cs_descriptor;
  bx_selector_t cs_selector;

  // interrupt vector must be within IDT table limits,
  // else #GP(vector*8 + 2 + EXT)
  if ((vector*16 + 15) > BX_CPU_THIS_PTR idtr.limit) {
    BX_ERROR(("interrupt(long mode): vector must be within IDT table limits, IDT.limit = 0x%x", BX_CPU_THIS_PTR idtr.limit));
    exception(BX_GP_EXCEPTION, vector*8 + 2);
  }

  Bit64u desctmp1 = system_read_qword(BX_CPU_THIS_PTR idtr.base + vector*16);
  Bit64u desctmp2 = system_read_qword(BX_CPU_THIS_PTR idtr.base + vector*16 + 8);

  if (desctmp2 & BX_CONST64(0x00001F0000000000)) {
    BX_ERROR(("interrupt(long mode): IDT entry extended attributes DWORD4 TYPE != 0"));
    exception(BX_GP_EXCEPTION, vector*8 + 2);
  }

  Bit32u dword1 = GET32L(desctmp1);
  Bit32u dword2 = GET32H(desctmp1);
  Bit32u dword3 = GET32L(desctmp2);

  parse_descriptor(dword1, dword2, &gate_descriptor);

  if ((gate_descriptor.valid==0) || gate_descriptor.segment)
  {
    BX_ERROR(("interrupt(long mode): gate descriptor is not valid sys seg"));
    exception(BX_GP_EXCEPTION, vector*8 + 2);
  }

  // descriptor AR byte must indicate interrupt gate, trap gate,
  // or task gate, else #GP(vector*8 + 2 + EXT)
  if (gate_descriptor.type != BX_386_INTERRUPT_GATE &&
      gate_descriptor.type != BX_386_TRAP_GATE)
  {
    BX_ERROR(("interrupt(long mode): unsupported gate type %u",
        (unsigned) gate_descriptor.type));
    exception(BX_GP_EXCEPTION, vector*8 + 2);
  }

  // if software interrupt, then gate descripor DPL must be >= CPL,
  // else #GP(vector * 8 + 2 + EXT)
  if (soft_int && gate_descriptor.dpl < CPL)
  {
    BX_ERROR(("interrupt(long mode): soft_int && gate.dpl < CPL"));
    exception(BX_GP_EXCEPTION, vector*8 + 2);
  }

  // Gate must be present, else #NP(vector * 8 + 2 + EXT)
  if (! IS_PRESENT(gate_descriptor)) {
    BX_ERROR(("interrupt(long mode): gate.p == 0"));
    exception(BX_NP_EXCEPTION, vector*8 + 2);
  }

  Bit16u gate_dest_selector = gate_descriptor.u.gate.dest_selector;
  Bit64u gate_dest_offset   = ((Bit64u)dword3 << 32) |
                       gate_descriptor.u.gate.dest_offset;

  unsigned ist = gate_descriptor.u.gate.param_count & 0x7;

  // examine CS selector and descriptor given in gate descriptor
  // selector must be non-null else #GP(EXT)
  if ((gate_dest_selector & 0xfffc) == 0) {
    BX_ERROR(("int_trap_gate(long mode): selector null"));
    exception(BX_GP_EXCEPTION, 0);
  }

  parse_selector(gate_dest_selector, &cs_selector);

  // selector must be within its descriptor table limits
  // else #GP(selector+EXT)
  fetch_raw_descriptor(&cs_selector, &dword1, &dword2, BX_GP_EXCEPTION);
  parse_descriptor(dword1, dword2, &cs_descriptor);

  // descriptor AR byte must indicate code seg
  // and code segment descriptor DPL<=CPL, else #GP(selector+EXT)
  if (cs_descriptor.valid==0 || cs_descriptor.segment==0 ||
      IS_DATA_SEGMENT(cs_descriptor.type) ||
      cs_descriptor.dpl > CPL)
  {
    BX_ERROR(("interrupt(long mode): not accessible or not code segment"));
    exception(BX_GP_EXCEPTION, cs_selector.value & 0xfffc);
  }

  // check that it's a 64 bit segment
  if (! IS_LONG64_SEGMENT(cs_descriptor) || cs_descriptor.u.segment.d_b)
  {
    BX_ERROR(("interrupt(long mode): must be 64 bit segment"));
    exception(BX_GP_EXCEPTION, cs_selector.value & 0xfffc);
  }

  // segment must be present, else #NP(selector + EXT)
  if (! IS_PRESENT(cs_descriptor)) {
    BX_ERROR(("interrupt(long mode): segment not present"));
    exception(BX_NP_EXCEPTION, cs_selector.value & 0xfffc);
  }
 
  Bit64u RSP_for_cpl_x;

  Bit64u old_CS  = BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].selector.value;
  Bit64u old_RIP = RIP;
  Bit64u old_SS  = BX_CPU_THIS_PTR sregs[BX_SEG_REG_SS].selector.value;
  Bit64u old_RSP = RSP;

  // if code segment is non-conforming and DPL < CPL then
  // INTERRUPT TO INNER PRIVILEGE:
  if (IS_CODE_SEGMENT_NON_CONFORMING(cs_descriptor.type) && cs_descriptor.dpl < CPL)
  {
    BX_DEBUG(("interrupt(long mode): INTERRUPT TO INNER PRIVILEGE"));

    // check selector and descriptor for new stack in current TSS
    if (ist > 0) {
      BX_DEBUG(("interrupt(long mode): trap to IST, vector = %d", ist));
      RSP_for_cpl_x = get_RSP_from_TSS(ist+3);
    }
    else {
      RSP_for_cpl_x = get_RSP_from_TSS(cs_descriptor.dpl);
    }

    // align stack
    RSP_for_cpl_x &= BX_CONST64(0xfffffffffffffff0);

    // push old stack long pointer onto new stack
    write_new_stack_qword_64(RSP_for_cpl_x -  8, cs_descriptor.dpl, old_SS);
    write_new_stack_qword_64(RSP_for_cpl_x - 16, cs_descriptor.dpl, old_RSP);
    write_new_stack_qword_64(RSP_for_cpl_x - 24, cs_descriptor.dpl, read_eflags());
    // push long pointer to return address onto new stack
    write_new_stack_qword_64(RSP_for_cpl_x - 32, cs_descriptor.dpl, old_CS);
    write_new_stack_qword_64(RSP_for_cpl_x - 40, cs_descriptor.dpl, old_RIP);
    RSP_for_cpl_x -= 40;

    if (push_error) {
      RSP_for_cpl_x -= 8;
      write_new_stack_qword_64(RSP_for_cpl_x, cs_descriptor.dpl, error_code);
    }

    // load CS:RIP (guaranteed to be in 64 bit mode)
    branch_far64(&cs_selector, &cs_descriptor, gate_dest_offset, cs_descriptor.dpl);

    // set up null SS descriptor
    load_null_selector(&BX_CPU_THIS_PTR sregs[BX_SEG_REG_SS], cs_descriptor.dpl);
  }
  else if(IS_CODE_SEGMENT_CONFORMING(cs_descriptor.type) || cs_descriptor.dpl==CPL) 
  {
    // if code segment is conforming OR code segment DPL = CPL then
    // INTERRUPT TO SAME PRIVILEGE LEVEL:

    BX_DEBUG(("interrupt(long mode): INTERRUPT TO SAME PRIVILEGE"));

    // check selector and descriptor for new stack in current TSS
    if (ist > 0) {
      BX_DEBUG(("interrupt(long mode): trap to IST, vector = %d", ist));
      RSP_for_cpl_x = get_RSP_from_TSS(ist+3);
    }
    else {
      RSP_for_cpl_x = RSP;
    }

    // align stack
    RSP_for_cpl_x &= BX_CONST64(0xfffffffffffffff0);

    // push flags onto stack
    // push current CS selector onto stack
    // push return offset onto stack
    write_new_stack_qword_64(RSP_for_cpl_x - 8,  cs_descriptor.dpl, old_SS);
    write_new_stack_qword_64(RSP_for_cpl_x - 16, cs_descriptor.dpl, old_RSP);
    write_new_stack_qword_64(RSP_for_cpl_x - 24, cs_descriptor.dpl, read_eflags());
    // push long pointer to return address onto new stack
    write_new_stack_qword_64(RSP_for_cpl_x - 32, cs_descriptor.dpl, old_CS);
    write_new_stack_qword_64(RSP_for_cpl_x - 40, cs_descriptor.dpl, old_RIP);
    RSP_for_cpl_x -= 40;

    if (push_error) {
      RSP_for_cpl_x -= 8;
      write_new_stack_qword_64(RSP_for_cpl_x, cs_descriptor.dpl, error_code);
    }

    // set the RPL field of CS to CPL
    branch_far64(&cs_selector, &cs_descriptor, gate_dest_offset, CPL);
  }
  else {
    BX_ERROR(("interrupt(long mode): bad descriptor type %u (CS.DPL=%u CPL=%u)",
      (unsigned) cs_descriptor.type, (unsigned) cs_descriptor.dpl, (unsigned) CPL));
    exception(BX_GP_EXCEPTION, cs_selector.value & 0xfffc);
  }

  RSP = RSP_for_cpl_x;

  // if interrupt gate then set IF to 0
  if (!(gate_descriptor.type & 1)) // even is int-gate
    BX_CPU_THIS_PTR clear_IF();
  BX_CPU_THIS_PTR clear_TF();
//BX_CPU_THIS_PTR clear_VM(); // VM is clear in long mode
  BX_CPU_THIS_PTR clear_RF();
  BX_CPU_THIS_PTR clear_NT();
}
Exemplo n.º 3
0
BX_CPU_C::call_gate64(bx_selector_t *gate_selector)
{
  bx_selector_t cs_selector;
  Bit32u dword1, dword2, dword3;
  bx_descriptor_t cs_descriptor;
  bx_descriptor_t gate_descriptor;

  // examine code segment selector in call gate descriptor
  BX_DEBUG(("call_gate64: CALL 64bit call gate"));

  fetch_raw_descriptor_64(gate_selector, &dword1, &dword2, &dword3, BX_GP_EXCEPTION);
  parse_descriptor(dword1, dword2, &gate_descriptor);

  Bit16u dest_selector = gate_descriptor.u.gate.dest_selector;
  // selector must not be null else #GP(0)
  if ((dest_selector & 0xfffc) == 0) {
    BX_ERROR(("call_gate64: selector in gate null"));
    exception(BX_GP_EXCEPTION, 0, 0);
  }

  parse_selector(dest_selector, &cs_selector);
  // selector must be within its descriptor table limits,
  //   else #GP(code segment selector)
  fetch_raw_descriptor(&cs_selector, &dword1, &dword2, BX_GP_EXCEPTION);
  parse_descriptor(dword1, dword2, &cs_descriptor);

  // find the RIP in the gate_descriptor
  Bit64u new_RIP = gate_descriptor.u.gate.dest_offset;
  new_RIP |= ((Bit64u)dword3 << 32);

  // AR byte of selected descriptor must indicate code segment,
  //   else #GP(code segment selector)
  // DPL of selected descriptor must be <= CPL,
  // else #GP(code segment selector)
  if (cs_descriptor.valid==0 || cs_descriptor.segment==0 ||
      IS_DATA_SEGMENT(cs_descriptor.type) ||
      cs_descriptor.dpl > CPL)
  {
    BX_ERROR(("call_gate64: selected descriptor is not code"));
    exception(BX_GP_EXCEPTION, dest_selector & 0xfffc, 0);
  }

  // In long mode, only 64-bit call gates are allowed, and they must point
  // to 64-bit code segments, else #GP(selector)
  if (! IS_LONG64_SEGMENT(cs_descriptor) || cs_descriptor.u.segment.d_b)
  {
    BX_ERROR(("call_gate64: not 64-bit code segment in call gate 64"));
    exception(BX_GP_EXCEPTION, dest_selector & 0xfffc, 0);
  }

  // code segment must be present else #NP(selector)
  if (! IS_PRESENT(cs_descriptor)) {
    BX_ERROR(("call_gate64: code segment not present !"));
    exception(BX_NP_EXCEPTION, dest_selector & 0xfffc, 0);
  }

  Bit64u old_CS  = BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].selector.value;
  Bit64u old_RIP = RIP;

  // CALL GATE TO MORE PRIVILEGE
  // if non-conforming code segment and DPL < CPL then
  if (IS_CODE_SEGMENT_NON_CONFORMING(cs_descriptor.type) && (cs_descriptor.dpl < CPL))
  {
    Bit64u RSP_for_cpl_x;

    BX_DEBUG(("CALL GATE TO MORE PRIVILEGE LEVEL"));

    // get new RSP for new privilege level from TSS
    get_RSP_from_TSS(cs_descriptor.dpl, &RSP_for_cpl_x);

    Bit64u old_SS  = BX_CPU_THIS_PTR sregs[BX_SEG_REG_SS].selector.value;
    Bit64u old_RSP = RSP;

    if (! IsCanonical(RSP_for_cpl_x)) {
      // #SS(selector) when changing priviledge level
      BX_ERROR(("call_gate64: canonical address failure %08x%08x",
         GET32H(RSP_for_cpl_x), GET32L(RSP_for_cpl_x)));
      exception(BX_SS_EXCEPTION, old_SS & 0xfffc, 0);
    }

    // push old stack long pointer onto new stack
    write_new_stack_qword_64(RSP_for_cpl_x -  8, cs_descriptor.dpl, old_SS);
    write_new_stack_qword_64(RSP_for_cpl_x - 16, cs_descriptor.dpl, old_RSP);
    // push long pointer to return address onto new stack
    write_new_stack_qword_64(RSP_for_cpl_x - 24, cs_descriptor.dpl, old_CS);
    write_new_stack_qword_64(RSP_for_cpl_x - 32, cs_descriptor.dpl, old_RIP);
    RSP_for_cpl_x -= 32;

    // prepare new stack null SS selector
    bx_selector_t ss_selector;
    bx_descriptor_t ss_descriptor;

    // set up a null descriptor
    parse_selector(0, &ss_selector);
    parse_descriptor(0, 0, &ss_descriptor);

    // load CS:RIP (guaranteed to be in 64 bit mode)
    branch_far64(&cs_selector, &cs_descriptor, new_RIP, cs_descriptor.dpl);

    // set up null SS descriptor
    load_ss(&ss_selector, &ss_descriptor, cs_descriptor.dpl);
    RSP = RSP_for_cpl_x;
  }
  else
  {
    BX_DEBUG(("CALL GATE TO SAME PRIVILEGE"));

    // push to 64-bit stack, switch to long64 guaranteed
    write_new_stack_qword_64(RSP -  8, CPL, old_CS);
    write_new_stack_qword_64(RSP - 16, CPL, old_RIP);
    RSP -= 16;

    // load CS:RIP (guaranteed to be in 64 bit mode)
    branch_far64(&cs_selector, &cs_descriptor, new_RIP, CPL);
  }
}