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();
}
}
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();
}
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);
}
}
