void gcomm::AsioUdpSocket::read_handler(const asio::error_code& ec,
size_t bytes_transferred)
{
if (ec)
{
//
return;
}
if (bytes_transferred >= NetHeader::serial_size_)
{
Critical<AsioProtonet> crit(net_);
NetHeader hdr;
try
{
unserialize(&recv_buf_[0], NetHeader::serial_size_, 0, hdr);
}
catch (gu::Exception& e)
{
log_warn << "hdr unserialize failed: " << e.get_errno();
return;
}
if (NetHeader::serial_size_ + hdr.len() != bytes_transferred)
{
log_warn << "len " << hdr.len()
<< " does not match to bytes transferred"
<< bytes_transferred;
}
else
{
Datagram dg(
gu::SharedBuffer(
new gu::Buffer(&recv_buf_[0] + NetHeader::serial_size_,
&recv_buf_[0] + NetHeader::serial_size_
+ hdr.len())));
if (net_.checksum_ == true && check_cs(hdr, dg))
{
log_warn << "checksum failed, hdr: len=" << hdr.len()
<< " has_crc32=" << hdr.has_crc32()
<< " has_crc32c=" << hdr.has_crc32c()
<< " crc32=" << hdr.crc32();
}
else
{
net_.dispatch(id(), dg, ProtoUpMeta());
}
}
}
else
{
log_warn << "short read of " << bytes_transferred;
}
async_receive();
}
BX_CPU_C::call_protected(bxInstruction_c *i, Bit16u cs_raw, bx_address disp)
{
bx_selector_t cs_selector;
Bit32u dword1, dword2;
bx_descriptor_t cs_descriptor;
/* new cs selector must not be null, else #GP(0) */
if ((cs_raw & 0xfffc) == 0) {
BX_ERROR(("call_protected: CS selector null"));
exception(BX_GP_EXCEPTION, 0, 0);
}
parse_selector(cs_raw, &cs_selector);
// check new CS selector index within its descriptor limits,
// else #GP(new CS selector)
fetch_raw_descriptor(&cs_selector, &dword1, &dword2, BX_GP_EXCEPTION);
parse_descriptor(dword1, dword2, &cs_descriptor);
// examine AR byte of selected descriptor for various legal values
if (cs_descriptor.valid==0) {
BX_ERROR(("call_protected: invalid CS descriptor"));
exception(BX_GP_EXCEPTION, cs_raw & 0xfffc, 0);
}
if (cs_descriptor.segment) // normal segment
{
check_cs(&cs_descriptor, cs_raw, BX_SELECTOR_RPL(cs_raw), CPL);
#if BX_SUPPORT_X86_64
if (i->os64L()) {
// push return address onto stack (CS padded to 64bits)
push_64((Bit64u) BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].selector.value);
push_64(RIP);
}
else
#endif
if (i->os32L()) {
// push return address onto stack (CS padded to 32bits)
push_32((Bit32u) BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].selector.value);
push_32(EIP);
}
else {
// push return address onto stack
push_16(BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].selector.value);
push_16(IP);
}
// load code segment descriptor into CS cache
// load CS with new code segment selector
// set RPL of CS to CPL
branch_far64(&cs_selector, &cs_descriptor, disp, CPL);
return;
}
else { // gate & special segment
bx_descriptor_t gate_descriptor = cs_descriptor;
bx_selector_t gate_selector = cs_selector;
Bit32u new_EIP;
Bit16u dest_selector;
Bit16u raw_tss_selector;
bx_selector_t tss_selector;
bx_descriptor_t tss_descriptor;
Bit32u temp_eIP;
// descriptor DPL must be >= CPL else #GP(gate selector)
if (gate_descriptor.dpl < CPL) {
BX_ERROR(("call_protected: descriptor.dpl < CPL"));
exception(BX_GP_EXCEPTION, cs_raw & 0xfffc, 0);
}
// descriptor DPL must be >= gate selector RPL else #GP(gate selector)
if (gate_descriptor.dpl < gate_selector.rpl) {
BX_ERROR(("call_protected: descriptor.dpl < selector.rpl"));
exception(BX_GP_EXCEPTION, cs_raw & 0xfffc, 0);
}
#if BX_SUPPORT_X86_64
if (long_mode()) {
// call gate type is higher priority than non-present bit check
if (gate_descriptor.type != BX_386_CALL_GATE) {
BX_ERROR(("call_protected: gate type %u unsupported in long mode", (unsigned) gate_descriptor.type));
exception(BX_GP_EXCEPTION, cs_raw & 0xfffc, 0);
}
}
else
#endif
{
switch (gate_descriptor.type) {
case BX_SYS_SEGMENT_AVAIL_286_TSS:
case BX_SYS_SEGMENT_AVAIL_386_TSS:
case BX_TASK_GATE:
case BX_286_CALL_GATE:
case BX_386_CALL_GATE:
break;
default:
BX_ERROR(("call_protected(): gate.type(%u) unsupported", (unsigned) gate_descriptor.type));
exception(BX_GP_EXCEPTION, cs_raw & 0xfffc, 0);
}
}
// gate descriptor must be present else #NP(gate selector)
if (! IS_PRESENT(gate_descriptor)) {
BX_ERROR(("call_protected: gate not present"));
exception(BX_NP_EXCEPTION, cs_raw & 0xfffc, 0);
}
#if BX_SUPPORT_X86_64
if (long_mode()) {
call_gate64(&gate_selector);
return;
}
#endif
switch (gate_descriptor.type) {
case BX_SYS_SEGMENT_AVAIL_286_TSS:
case BX_SYS_SEGMENT_AVAIL_386_TSS:
if (gate_descriptor.type==BX_SYS_SEGMENT_AVAIL_286_TSS)
BX_DEBUG(("call_protected: 16bit available TSS"));
else
BX_DEBUG(("call_protected: 32bit available TSS"));
// SWITCH_TASKS _without_ nesting to TSS
task_switch(&gate_selector, &gate_descriptor,
BX_TASK_FROM_CALL_OR_INT, dword1, dword2);
// EIP must be in code seg limit, else #GP(0)
if (EIP > BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].cache.u.segment.limit_scaled) {
BX_ERROR(("call_protected: EIP not within CS limits"));
exception(BX_GP_EXCEPTION, 0, 0);
}
return;
case BX_TASK_GATE:
// examine selector to TSS, given in Task Gate descriptor
// must specify global in the local/global bit else #TS(TSS selector)
raw_tss_selector = gate_descriptor.u.taskgate.tss_selector;
parse_selector(raw_tss_selector, &tss_selector);
if (tss_selector.ti) {
BX_ERROR(("call_protected: tss_selector.ti=1"));
exception(BX_GP_EXCEPTION, raw_tss_selector & 0xfffc, 0);
}
// index must be within GDT limits else #TS(TSS selector)
fetch_raw_descriptor(&tss_selector, &dword1, &dword2, BX_GP_EXCEPTION);
parse_descriptor(dword1, dword2, &tss_descriptor);
// descriptor AR byte must specify available TSS
// else #GP(TSS selector)
if (tss_descriptor.valid==0 || tss_descriptor.segment) {
BX_ERROR(("call_protected: TSS selector points to bad TSS"));
exception(BX_GP_EXCEPTION, raw_tss_selector & 0xfffc, 0);
}
if (tss_descriptor.type!=BX_SYS_SEGMENT_AVAIL_286_TSS &&
tss_descriptor.type!=BX_SYS_SEGMENT_AVAIL_386_TSS)
{
BX_ERROR(("call_protected: TSS selector points to bad TSS"));
exception(BX_GP_EXCEPTION, raw_tss_selector & 0xfffc, 0);
}
// task state segment must be present, else #NP(tss selector)
if (! IS_PRESENT(tss_descriptor)) {
BX_ERROR(("call_protected: task descriptor.p == 0"));
exception(BX_NP_EXCEPTION, raw_tss_selector & 0xfffc, 0);
}
// SWITCH_TASKS without nesting to TSS
task_switch(&tss_selector, &tss_descriptor,
BX_TASK_FROM_CALL_OR_INT, dword1, dword2);
// EIP must be within code segment limit, else #TS(0)
if (BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].cache.u.segment.d_b)
temp_eIP = EIP;
else
temp_eIP = IP;
if (temp_eIP > BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].cache.u.segment.limit_scaled)
{
BX_ERROR(("call_protected: EIP > CS.limit"));
exception(BX_GP_EXCEPTION, 0, 0);
}
return;
case BX_286_CALL_GATE:
case BX_386_CALL_GATE:
// examine code segment selector in call gate descriptor
BX_DEBUG(("call_protected: call gate"));
dest_selector = gate_descriptor.u.gate.dest_selector;
new_EIP = gate_descriptor.u.gate.dest_offset;
// selector must not be null else #GP(0)
if ((dest_selector & 0xfffc) == 0) {
BX_ERROR(("call_protected: 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);
// 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_protected: selected descriptor is not code"));
exception(BX_GP_EXCEPTION, dest_selector & 0xfffc, 0);
}
// code segment must be present else #NP(selector)
if (! IS_PRESENT(cs_descriptor)) {
BX_ERROR(("call_protected: code segment not present !"));
exception(BX_NP_EXCEPTION, dest_selector & 0xfffc, 0);
}
// 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))
{
Bit16u SS_for_cpl_x;
Bit32u ESP_for_cpl_x;
bx_selector_t ss_selector;
bx_descriptor_t ss_descriptor;
Bit16u return_SS, return_CS;
Bit32u return_ESP, return_EIP;
Bit16u parameter_word[32];
Bit32u parameter_dword[32];
BX_DEBUG(("CALL GATE TO MORE PRIVILEGE LEVEL"));
// get new SS selector for new privilege level from TSS
get_SS_ESP_from_TSS(cs_descriptor.dpl, &SS_for_cpl_x, &ESP_for_cpl_x);
// check selector & descriptor for new SS:
// selector must not be null, else #TS(0)
if ((SS_for_cpl_x & 0xfffc) == 0) {
BX_ERROR(("call_protected: new SS null"));
exception(BX_TS_EXCEPTION, 0, 0);
}
// selector index must be within its descriptor table limits,
// else #TS(SS selector)
parse_selector(SS_for_cpl_x, &ss_selector);
fetch_raw_descriptor(&ss_selector, &dword1, &dword2, BX_TS_EXCEPTION);
parse_descriptor(dword1, dword2, &ss_descriptor);
// selector's RPL must equal DPL of code segment,
// else #TS(SS selector)
if (ss_selector.rpl != cs_descriptor.dpl) {
BX_ERROR(("call_protected: SS selector.rpl != CS descr.dpl"));
exception(BX_TS_EXCEPTION, SS_for_cpl_x & 0xfffc, 0);
}
// stack segment DPL must equal DPL of code segment,
// else #TS(SS selector)
if (ss_descriptor.dpl != cs_descriptor.dpl) {
BX_ERROR(("call_protected: SS descr.rpl != CS descr.dpl"));
exception(BX_TS_EXCEPTION, SS_for_cpl_x & 0xfffc, 0);
}
// descriptor must indicate writable data segment,
// else #TS(SS 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(("call_protected: ss descriptor is not writable data seg"));
exception(BX_TS_EXCEPTION, SS_for_cpl_x & 0xfffc, 0);
}
// segment must be present, else #SS(SS selector)
if (! IS_PRESENT(ss_descriptor)) {
BX_ERROR(("call_protected: ss descriptor not present"));
exception(BX_SS_EXCEPTION, SS_for_cpl_x & 0xfffc, 0);
}
// get word count from call gate, mask to 5 bits
unsigned param_count = gate_descriptor.u.gate.param_count & 0x1f;
// save return SS:eSP to be pushed on new stack
return_SS = BX_CPU_THIS_PTR sregs[BX_SEG_REG_SS].selector.value;
if (BX_CPU_THIS_PTR sregs[BX_SEG_REG_SS].cache.u.segment.d_b)
return_ESP = ESP;
else
return_ESP = SP;
// save return CS:eIP to be pushed on new stack
return_CS = BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].selector.value;
if (cs_descriptor.u.segment.d_b)
return_EIP = EIP;
else
return_EIP = IP;
if (gate_descriptor.type==BX_286_CALL_GATE) {
for (unsigned i=0; i<param_count; i++) {
parameter_word[i] = read_virtual_word(BX_SEG_REG_SS, return_ESP + i*2);
}
}
else {
for (unsigned i=0; i<param_count; i++) {
parameter_dword[i] = read_virtual_dword(BX_SEG_REG_SS, return_ESP + i*4);
}
}
// Prepare new stack segment
bx_segment_reg_t new_stack;
new_stack.selector = ss_selector;
new_stack.cache = ss_descriptor;
new_stack.selector.rpl = cs_descriptor.dpl;
// add cpl to the selector value
new_stack.selector.value = (0xfffc & new_stack.selector.value) |
new_stack.selector.rpl;
/* load new SS:SP value from TSS */
if (ss_descriptor.u.segment.d_b) {
Bit32u temp_ESP = ESP_for_cpl_x;
// push pointer of old stack onto new stack
if (gate_descriptor.type==BX_386_CALL_GATE) {
write_new_stack_dword_32(&new_stack, temp_ESP-4, cs_descriptor.dpl, return_SS);
write_new_stack_dword_32(&new_stack, temp_ESP-8, cs_descriptor.dpl, return_ESP);
temp_ESP -= 8;
for (unsigned i=param_count; i>0; i--) {
temp_ESP -= 4;
write_new_stack_dword_32(&new_stack, temp_ESP, cs_descriptor.dpl, parameter_dword[i-1]);
}
// push return address onto new stack
write_new_stack_dword_32(&new_stack, temp_ESP-4, cs_descriptor.dpl, return_CS);
write_new_stack_dword_32(&new_stack, temp_ESP-8, cs_descriptor.dpl, return_EIP);
temp_ESP -= 8;
}
else {
write_new_stack_word_32(&new_stack, temp_ESP-2, cs_descriptor.dpl, return_SS);
write_new_stack_word_32(&new_stack, temp_ESP-4, cs_descriptor.dpl, (Bit16u) return_ESP);
temp_ESP -= 4;
for (unsigned i=param_count; i>0; i--) {
temp_ESP -= 2;
write_new_stack_word_32(&new_stack, temp_ESP, cs_descriptor.dpl, parameter_word[i-1]);
}
// push return address onto new stack
write_new_stack_word_32(&new_stack, temp_ESP-2, cs_descriptor.dpl, return_CS);
write_new_stack_word_32(&new_stack, temp_ESP-4, cs_descriptor.dpl, (Bit16u) return_EIP);
temp_ESP -= 4;
}
ESP = temp_ESP;
}
else {
Bit16u temp_SP = (Bit16u) ESP_for_cpl_x;
// push pointer of old stack onto new stack
if (gate_descriptor.type==BX_386_CALL_GATE) {
write_new_stack_dword_32(&new_stack, (Bit16u)(temp_SP-4), cs_descriptor.dpl, return_SS);
write_new_stack_dword_32(&new_stack, (Bit16u)(temp_SP-8), cs_descriptor.dpl, return_ESP);
temp_SP -= 8;
for (unsigned i=param_count; i>0; i--) {
temp_SP -= 4;
write_new_stack_dword_32(&new_stack, temp_SP, cs_descriptor.dpl, parameter_dword[i-1]);
}
// push return address onto new stack
write_new_stack_dword_32(&new_stack, (Bit16u)(temp_SP-4), cs_descriptor.dpl, return_CS);
write_new_stack_dword_32(&new_stack, (Bit16u)(temp_SP-8), cs_descriptor.dpl, return_EIP);
temp_SP -= 8;
}
else {
write_new_stack_word_32(&new_stack, (Bit16u)(temp_SP-2), cs_descriptor.dpl, return_SS);
write_new_stack_word_32(&new_stack, (Bit16u)(temp_SP-4), cs_descriptor.dpl, (Bit16u) return_ESP);
temp_SP -= 4;
for (unsigned i=param_count; i>0; i--) {
temp_SP -= 2;
write_new_stack_word_32(&new_stack, temp_SP, cs_descriptor.dpl, parameter_word[i-1]);
}
// push return address onto new stack
write_new_stack_word_32(&new_stack, (Bit16u)(temp_SP-2), cs_descriptor.dpl, return_CS);
write_new_stack_word_32(&new_stack, (Bit16u)(temp_SP-4), cs_descriptor.dpl, (Bit16u) return_EIP);
temp_SP -= 4;
}
SP = temp_SP;
}
// new eIP must be in code segment limit else #GP(0)
if (new_EIP > cs_descriptor.u.segment.limit_scaled) {
BX_ERROR(("call_protected: EIP not within CS limits"));
exception(BX_GP_EXCEPTION, 0, 0);
}
/* load SS descriptor */
load_ss(&ss_selector, &ss_descriptor, cs_descriptor.dpl);
/* load new CS:IP value from gate */
/* load CS descriptor */
/* set CPL to stack segment DPL */
/* set RPL of CS to CPL */
load_cs(&cs_selector, &cs_descriptor, cs_descriptor.dpl);
EIP = new_EIP;
}
else // CALL GATE TO SAME PRIVILEGE
{
BX_DEBUG(("CALL GATE TO SAME PRIVILEGE"));
if (gate_descriptor.type == BX_386_CALL_GATE) {
// call gate 32bit, push return address onto stack
push_32(BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].selector.value);
push_32(EIP);
}
else {
// call gate 16bit, push return address onto stack
push_16(BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].selector.value);
push_16(IP);
}
// load CS:EIP from gate
// load code segment descriptor into CS register
// set RPL of CS to CPL
branch_far32(&cs_selector, &cs_descriptor, new_EIP, CPL);
}
return;
default: // can't get here
BX_PANIC(("call_protected: gate type %u unsupported", (unsigned) cs_descriptor.type));
exception(BX_GP_EXCEPTION, cs_raw & 0xfffc, 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();
}
}
BX_CPU_C::call_protected(bxInstruction_c *i, Bit16u cs_raw, bx_address disp)
{
bx_selector_t cs_selector;
Bit32u dword1, dword2;
bx_descriptor_t cs_descriptor;
/* new cs selector must not be null, else #GP(0) */
if ((cs_raw & 0xfffc) == 0) {
BX_ERROR(("call_protected: CS selector null"));
exception(BX_GP_EXCEPTION, 0);
}
parse_selector(cs_raw, &cs_selector);
// check new CS selector index within its descriptor limits,
// else #GP(new CS selector)
fetch_raw_descriptor(&cs_selector, &dword1, &dword2, BX_GP_EXCEPTION);
parse_descriptor(dword1, dword2, &cs_descriptor);
// examine AR byte of selected descriptor for various legal values
if (cs_descriptor.valid==0) {
BX_ERROR(("call_protected: invalid CS descriptor"));
exception(BX_GP_EXCEPTION, cs_raw & 0xfffc);
}
if (cs_descriptor.segment) // normal segment
{
check_cs(&cs_descriptor, cs_raw, BX_SELECTOR_RPL(cs_raw), CPL);
#if BX_SUPPORT_X86_64
if (long_mode() && cs_descriptor.u.segment.l) {
Bit64u temp_rsp = RSP;
// moving to long mode, push return address onto 64-bit stack
if (i->os64L()) {
write_new_stack_qword_64(temp_rsp - 8, cs_descriptor.dpl,
BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].selector.value);
write_new_stack_qword_64(temp_rsp - 16, cs_descriptor.dpl, RIP);
temp_rsp -= 16;
}
else if (i->os32L()) {
write_new_stack_dword_64(temp_rsp - 4, cs_descriptor.dpl,
BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].selector.value);
write_new_stack_dword_64(temp_rsp - 8, cs_descriptor.dpl, EIP);
temp_rsp -= 8;
}
else {
write_new_stack_word_64(temp_rsp - 2, cs_descriptor.dpl,
BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].selector.value);
write_new_stack_word_64(temp_rsp - 4, cs_descriptor.dpl, IP);
temp_rsp -= 4;
}
// load code segment descriptor into CS cache
// load CS with new code segment selector
// set RPL of CS to CPL
branch_far64(&cs_selector, &cs_descriptor, disp, CPL);
RSP = temp_rsp;
}
else
#endif
{
Bit32u temp_RSP;
// moving to legacy mode, push return address onto 32-bit stack
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()) {
write_new_stack_qword_32(&BX_CPU_THIS_PTR sregs[BX_SEG_REG_SS],
temp_RSP - 8, cs_descriptor.dpl,
BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].selector.value);
write_new_stack_qword_32(&BX_CPU_THIS_PTR sregs[BX_SEG_REG_SS],
temp_RSP - 16, cs_descriptor.dpl, RIP);
temp_RSP -= 16;
}
else
#endif
if (i->os32L()) {
write_new_stack_dword_32(&BX_CPU_THIS_PTR sregs[BX_SEG_REG_SS],
temp_RSP - 4, cs_descriptor.dpl,
BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].selector.value);
write_new_stack_dword_32(&BX_CPU_THIS_PTR sregs[BX_SEG_REG_SS],
temp_RSP - 8, cs_descriptor.dpl, EIP);
temp_RSP -= 8;
}
else {
write_new_stack_word_32(&BX_CPU_THIS_PTR sregs[BX_SEG_REG_SS],
temp_RSP - 2, cs_descriptor.dpl,
BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].selector.value);
write_new_stack_word_32(&BX_CPU_THIS_PTR sregs[BX_SEG_REG_SS],
temp_RSP - 4, cs_descriptor.dpl, IP);
temp_RSP -= 4;
}
// load code segment descriptor into CS cache
// load CS with new code segment selector
// set RPL of CS to CPL
branch_far64(&cs_selector, &cs_descriptor, disp, CPL);
if (BX_CPU_THIS_PTR sregs[BX_SEG_REG_SS].cache.u.segment.d_b)
ESP = (Bit32u) temp_RSP;
else
SP = (Bit16u) temp_RSP;
}
return;
}
else { // gate & special segment
bx_descriptor_t gate_descriptor = cs_descriptor;
bx_selector_t gate_selector = cs_selector;
// descriptor DPL must be >= CPL else #GP(gate selector)
if (gate_descriptor.dpl < CPL) {
BX_ERROR(("call_protected: descriptor.dpl < CPL"));
exception(BX_GP_EXCEPTION, cs_raw & 0xfffc);
}
// descriptor DPL must be >= gate selector RPL else #GP(gate selector)
if (gate_descriptor.dpl < gate_selector.rpl) {
BX_ERROR(("call_protected: descriptor.dpl < selector.rpl"));
exception(BX_GP_EXCEPTION, cs_raw & 0xfffc);
}
#if BX_SUPPORT_X86_64
if (long_mode()) {
// call gate type is higher priority than non-present bit check
if (gate_descriptor.type != BX_386_CALL_GATE) {
BX_ERROR(("call_protected: gate type %u unsupported in long mode", (unsigned) gate_descriptor.type));
exception(BX_GP_EXCEPTION, cs_raw & 0xfffc);
}
// gate descriptor must be present else #NP(gate selector)
if (! IS_PRESENT(gate_descriptor)) {
BX_ERROR(("call_protected: call gate not present"));
exception(BX_NP_EXCEPTION, cs_raw & 0xfffc);
}
call_gate64(&gate_selector);
return;
}
#endif
switch (gate_descriptor.type) {
case BX_SYS_SEGMENT_AVAIL_286_TSS:
case BX_SYS_SEGMENT_AVAIL_386_TSS:
if (gate_descriptor.type==BX_SYS_SEGMENT_AVAIL_286_TSS)
BX_DEBUG(("call_protected: 16bit available TSS"));
else
BX_DEBUG(("call_protected: 32bit available TSS"));
if (gate_descriptor.valid==0 || gate_selector.ti) {
BX_ERROR(("call_protected: call bad TSS selector !"));
exception(BX_GP_EXCEPTION, cs_raw & 0xfffc);
}
// TSS must be present, else #NP(TSS selector)
if (! IS_PRESENT(gate_descriptor)) {
BX_ERROR(("call_protected: call not present TSS !"));
exception(BX_NP_EXCEPTION, cs_raw & 0xfffc);
}
// SWITCH_TASKS _without_ nesting to TSS
task_switch(i, &gate_selector, &gate_descriptor,
BX_TASK_FROM_CALL, dword1, dword2);
// EIP must be in code seg limit, else #GP(0)
if (EIP > BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].cache.u.segment.limit_scaled) {
BX_ERROR(("call_protected: EIP not within CS limits"));
exception(BX_GP_EXCEPTION, 0);
}
return;
case BX_TASK_GATE:
task_gate(i, &gate_selector, &gate_descriptor, BX_TASK_FROM_CALL);
return;
case BX_286_CALL_GATE:
case BX_386_CALL_GATE:
// gate descriptor must be present else #NP(gate selector)
if (! IS_PRESENT(gate_descriptor)) {
BX_ERROR(("call_protected: gate not present"));
exception(BX_NP_EXCEPTION, cs_raw & 0xfffc);
}
call_gate(&gate_descriptor);
return;
default: // can't get here
BX_ERROR(("call_protected(): gate.type(%u) unsupported", (unsigned) gate_descriptor.type));
exception(BX_GP_EXCEPTION, cs_raw & 0xfffc);
}
}
}
