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::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, 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::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); } }
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); } } }