///////////////////////////////////////////////////////////////////////// // $Id: paging.cc,v 1.42 2003-03-02 23:59:09 cbothamy Exp $ ///////////////////////////////////////////////////////////////////////// // // Copyright (C) 2001 MandrakeSoft S.A. // // MandrakeSoft S.A. // 43, rue d'Aboukir // 75002 Paris - France // http://www.linux-mandrake.com/ // http://www.mandrakesoft.com/ // // This library is free software; you can redistribute it and/or // modify it under the terms of the GNU Lesser General Public // License as published by the Free Software Foundation; either // version 2 of the License, or (at your option) any later version. // // This library is distributed in the hope that it will be useful, // but WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU // Lesser General Public License for more details. // // You should have received a copy of the GNU Lesser General Public // License along with this library; if not, write to the Free Software // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA // Notes from merge of x86-64 enhancements: (KPL) // Looks like for x86-64/PAE=1/PTE with PSE=1, the // CR4.PSE field is not consulted by the processor? // Fix the PAE case to not update the page table tree entries // until the final protection check? This is how it is on // P6 for non-PAE anyways... #define NEED_CPU_REG_SHORTCUTS 1 #include "bochs.h" #define LOG_THIS BX_CPU_THIS_PTR #if BX_USE_CPU_SMF #define this (BX_CPU(0)) #endif #if 0 // X86 Registers Which Affect Paging: // ================================== // // CR0: // bit 31: PG, Paging (386+) // bit 16: WP, Write Protect (486+) // 0: allow supervisor level writes into user level RO pages // 1: inhibit supervisor level writes into user level RO pages // // CR3: // bit 31..12: PDBR, Page Directory Base Register (386+) // bit 4: PCD, Page level Cache Disable (486+) // Controls caching of current page directory. Affects only the processor's // internal caches (L1 and L2). // This flag ignored if paging disabled (PG=0) or cache disabled (CD=1). // Values: // 0: Page Directory can be cached // 1: Page Directory not cached // bit 3: PWT, Page level Writes Transparent (486+) // Controls write-through or write-back caching policy of current page // directory. Affects only the processor's internal caches (L1 and L2). // This flag ignored if paging disabled (PG=0) or cache disabled (CD=1). // Values: // 0: write-back caching enabled // 1: write-through caching enabled // // CR4: // bit 4: PSE, Page Size Extension (Pentium+) // 0: 4KByte pages (typical) // 1: 4MByte or 2MByte pages // bit 5: PAE, Physical Address Extension (Pentium Pro+) // 0: 32bit physical addresses // 1: 36bit physical addresses // bit 7: PGE, Page Global Enable (Pentium Pro+) // The global page feature allows frequently used or shared pages // to be marked as global (PDE or PTE bit 8). Global pages are // not flushed from TLB on a task switch or write to CR3. // Values: // 0: disables global page feature // 1: enables global page feature // // Page size extention and physical address size extention matrix // ==================================================================== // CR0.PG CR4.PAE CR4.PSE PDE.PS | page size physical address size // ==================================================================== // 0 X X X | - paging disabled // 1 0 0 X | 4K 32bits // 1 0 1 0 | 4K 32bits // 1 0 1 1 | 4M 32bits // 1 1 X 0 | 4K 36bits // 1 1 X 1 | 2M 36bits // Page Directory/Table Entry format when P=0: // =========================================== // // 31.. 1: available // 0: P=0 // Page Directory Entry format when P=1 (4-Kbyte Page Table): // ========================================================== // // 31..12: page table base address // 11.. 9: available // 8: G (Pentium Pro+), 0=reserved otherwise // 7: PS (Pentium+), 0=reserved otherwise // 6: 0=reserved // 5: A (386+) // 4: PCD (486+), 0=reserved otherwise // 3: PWT (486+), 0=reserved otherwise // 2: U/S (386+) // 1: R/W (386+) // 0: P=1 (386+) // Page Table Entry format when P=1 (4-Kbyte Page): // ================================================ // // 31..12: page base address // 11.. 9: available // 8: G (Pentium Pro+), 0=reserved otherwise // 7: 0=reserved // 6: D (386+) // 5: A (386+) // 4: PCD (486+), 0=reserved otherwise // 3: PWT (486+), 0=reserved otherwise // 2: U/S (386+) // 1: R/W (386+) // 0: P=1 (386+) // Page Directory/Table Entry Fields Defined: // ========================================== // G: Global flag // Indiciates a global page when set. When a page is marked // global and the PGE flag in CR4 is set, the page table or // directory entry for the page is not invalidated in the TLB // when CR3 is loaded or a task switch occurs. Only software // clears and sets this flag. For page directory entries that // point to page tables, this flag is ignored and the global // characteristics of a page are set in the page table entries. // // PS: Page Size flag // Only used in page directory entries. When PS=0, the page // size is 4KBytes and the page directory entry points to a // page table. When PS=1, the page size is 4MBytes for // normal 32-bit addressing and 2MBytes if extended physical // addressing // // D: Dirty bit: // Processor sets the Dirty bit in the 2nd-level page table before a // write operation to an address mapped by that page table entry. // Dirty bit in directory entries is undefined. // // A: Accessed bit: // Processor sets the Accessed bits in both levels of page tables before // a read/write operation to a page. // // PCD: Page level Cache Disable // Controls caching of individual pages or page tables. // This allows a per-page based mechanism to disable caching, for // those pages which contained memory mapped IO, or otherwise // should not be cached. Processor ignores this flag if paging // is not used (CR0.PG=0) or the cache disable bit is set (CR0.CD=1). // Values: // 0: page or page table can be cached // 1: page or page table is not cached (prevented) // // PWT: Page level Write Through // Controls the write-through or write-back caching policy of individual // pages or page tables. Processor ignores this flag if paging // is not used (CR0.PG=0) or the cache disable bit is set (CR0.CD=1). // Values: // 0: write-back caching // 1: write-through caching // // U/S: User/Supervisor level // 0: Supervisor level - for the OS, drivers, etc. // 1: User level - application code and data // // R/W: Read/Write access // 0: read-only access // 1: read/write access // // P: Present // 0: Not present // 1: Present // ========================================== // Combined page directory/page table protection: // ============================================== // There is one column for the combined effect on a 386 // and one column for the combined effect on a 486+ CPU. // // +----------------+-----------------+----------------+----------------+ // | Page Directory| Page Table | Combined 386 | Combined 486+ | // |Privilege Type | Privilege Type | Privilege Type| Privilege Type| // |----------------+-----------------+----------------+----------------| // |User R | User R | User R | User R | // |User R | User RW | User R | User R | // |User RW | User R | User R | User R | // |User RW | User RW | User RW | User RW | // |User R | Supervisor R | User R | Supervisor RW | // |User R | Supervisor RW | User R | Supervisor RW | // |User RW | Supervisor R | User R | Supervisor RW | // |User RW | Supervisor RW | User RW | Supervisor RW | // |Supervisor R | User R | User R | Supervisor RW | // |Supervisor R | User RW | User R | Supervisor RW | // |Supervisor RW | User R | User R | Supervisor RW | // |Supervisor RW | User RW | User RW | Supervisor RW | // |Supervisor R | Supervisor R | Supervisor RW | Supervisor RW | // |Supervisor R | Supervisor RW | Supervisor RW | Supervisor RW | // |Supervisor RW | Supervisor R | Supervisor RW | Supervisor RW | // |Supervisor RW | Supervisor RW | Supervisor RW | Supervisor RW | // +----------------+-----------------+----------------+----------------+ // Page Fault Error Code Format: // ============================= // // bits 31..4: Reserved // bit 3: RSVD (Pentium Pro+) // 0: fault caused by reserved bits set to 1 in a page directory // when the PSE or PAE flags in CR4 are set to 1 // 1: fault was not caused by reserved bit violation // bit 2: U/S (386+) // 0: fault originated when in supervior mode // 1: fault originated when in user mode // bit 1: R/W (386+) // 0: access causing the fault was a read // 1: access causing the fault was a write // bit 0: P (386+) // 0: fault caused by a nonpresent page // 1: fault caused by a page level protection violation // Some paging related notes: // ========================== // // - When the processor is running in supervisor level, all pages are both // readable and writable (write-protect ignored). When running at user // level, only pages which belong to the user level are accessible; // read/write & read-only are readable, read/write are writable. // // - If the Present bit is 0 in either level of page table, an // access which uses these entries will generate a page fault. // // - (A)ccess bit is used to report read or write access to a page // or 2nd level page table. // // - (D)irty bit is used to report write access to a page. // // - Processor running at CPL=0,1,2 maps to U/S=0 // Processor running at CPL=3 maps to U/S=1 // // - Pentium+ processors have separate TLB's for data and instruction caches // - Pentium Pro+ processors maintain separate 4K and 4M TLBs. #endif #if BX_SUPPORT_PAGING #define BX_INVALID_TLB_ENTRY 0xffffffff #if BX_USE_QUICK_TLB_INVALIDATE #define BX_MAX_TLB_INVALIDATE 0xffe #endif #define BX_USE_TLB_GENERATION 1 #if BX_CPU_LEVEL >= 4 # define BX_PRIV_CHECK_SIZE 32 #else # define BX_PRIV_CHECK_SIZE 16 #endif // The 'priv_check' array is used to decide if the current access // has the proper paging permissions. An index is formed, based // on parameters such as the access type and level, the write protect // flag and values cached in the TLB. The format of the index into this // array is: // // |4 |3 |2 |1 |0 | // |wp|us|us|rw|rw| // | | | | | // | | | | +---> r/w of current access // | | +--+------> u/s,r/w combined of page dir & table (cached) // | +------------> u/s of current access // +---------------> Current CR0.wp value // Each entry in the TLB cache has 3 entries: // lpf: Linear Page Frame (page aligned linear address of page) // bits 32..12 Linear page frame. // bits 11..0 Invalidate index. // ppf: Physical Page Frame (page aligned phy address of page) // accessBits: // bits 32..11: Host Page Frame address used for direct access to // the mem.vector[] space allocated for the guest physical // memory. If this is zero, it means that a pointer // to the host space could not be generated, likely because // that page of memory is not standard memory (it might // be memory mapped IO, ROM, etc). // bits 10..4: (currently unused) // // The following 4 bits are used for a very efficient permissions // check. The goal is to be able, using only the current privilege // level and access type, to determine if the page tables allow the // access to occur or at least should rewalk the page tables. On // the first read access, permissions are set to only read, so a // rewalk is necessary when a subsequent write fails the tests. // This allows for the dirty bit to be set properly, but for the // test to be efficient. Note that the CR0.WP flag is not present. // The values in the following flags is based on the current CR0.WP // value, necessitating a TLB flush when CR0.WP changes. // // The test is: // OK = 1 << ( (W<<1) | U ) [W:1=write, 0=read, U:1=CPL3,0=CPL0-2] // // Thus for reads, it's simply: // OK = 1 << ( U ) // // bit 8: Page is a global page. // bit 3: a Write from User privilege is OK // bit 2: a Write from System privilege is OK // bit 1: a Read from User privilege is OK // bit 0: a Read from System privilege is OK #define WriteUserOK 0x08 #define WriteSysOK 0x04 #define ReadUserOK 0x02 #define ReadSysOK 0x01 #ifdef __GNUC__ #warning "Move priv_check to CPU fields, or init.cc" #endif static unsigned priv_check[BX_PRIV_CHECK_SIZE]; // === TLB Instrumentation section ============================== // Note: this is an approximation of what Peter Tattam had. #define InstrumentTLB 0 #if InstrumentTLB static unsigned tlbLookups=0; static unsigned tlbMisses=0; static unsigned tlbGlobalFlushes=0; static unsigned tlbNonGlobalFlushes=0; static unsigned tlbEntryFlushes=0; static unsigned tlbEntryInvlpg=0; #define InstrTLB_StatsMask 0xfffff #define InstrTLB_Stats() {\ if ((tlbLookups & InstrTLB_StatsMask) == 0) { \ BX_INFO(("TLB lookup:%8d miss:%8d %6.2f%% flush:%8d %6.2f%%", \ tlbLookups, \ tlbMisses, \ tlbMisses * 100.0 / tlbLookups, \ (tlbGlobalFlushes+tlbNonGlobalFlushes), \ (tlbGlobalFlushes+tlbNonGlobalFlushes) * 100.0 / tlbLookups \ )); \ tlbLookups = tlbMisses = tlbGlobalFlushes = tlbNonGlobalFlushes = 0; \ } \ } #define InstrTLB_Increment(v) (v)++ #else #define InstrTLB_Stats() #define InstrTLB_Increment(v) #endif // ============================================================== void BX_CPP_AttrRegparmN(2) BX_CPU_C::pagingCR0Changed(Bit32u oldCR0, Bit32u newCR0) { // Modification of PG,PE flushes TLB cache according to docs. // Additionally, the TLB strategy is based on the current value of // WP, so if that changes we must also flush the TLB. if ( (oldCR0 & 0x80010001) != (newCR0 & 0x80010001) ) TLB_flush(1); // 1 = Flush Global entries also. if (bx_dbg.paging) BX_INFO(("pagingCR0Changed(0x%x -> 0x%x):", oldCR0, newCR0)); } void BX_CPP_AttrRegparmN(2) BX_CPU_C::pagingCR4Changed(Bit32u oldCR4, Bit32u newCR4) { // Modification of PGE,PAE,PSE flushes TLB cache according to docs. if ( (oldCR4 & 0x000000b0) != (newCR4 & 0x000000b0) ) TLB_flush(1); // 1 = Flush Global entries also. if (bx_dbg.paging) BX_INFO(("pagingCR4Changed(0x%x -> 0x%x):", oldCR4, newCR4)); } void BX_CPP_AttrRegparmN(1) BX_CPU_C::CR3_change(bx_address value) { if (bx_dbg.paging) { BX_INFO(("CR3_change(): flush TLB cache")); BX_INFO(("Page Directory Base %08x", (unsigned) value)); } // flush TLB even if value does not change TLB_flush(0); // 0 = Don't flush Global entries. BX_CPU_THIS_PTR cr3 = value; } void BX_CPU_C::pagingA20Changed(void) { TLB_flush(1); // 1 = Flush Global entries too. } void BX_CPU_C::TLB_init(void) { // Called to initialize the TLB upon startup. // Unconditional initialization of all TLB entries. #if BX_USE_TLB unsigned i; unsigned wp, us_combined, rw_combined, us_current, rw_current; for (i=0; i> 4; us_current = (i & 0x08) >> 3; us_combined = (i & 0x04) >> 2; rw_combined = (i & 0x02) >> 1; rw_current = (i & 0x01) >> 0; if (wp) { // when write protect on if (us_current > us_combined) // user access, supervisor page priv_check[i] = 0; else if (rw_current > rw_combined) // RW access, RO page priv_check[i] = 0; else priv_check[i] = 1; } else { // when write protect off if (us_current == 0) // Supervisor mode access, anything goes priv_check[i] = 1; else { // user mode access if (us_combined == 0) // user access, supervisor Page priv_check[i] = 0; else if (rw_current > rw_combined) // RW access, RO page priv_check[i] = 0; else priv_check[i] = 1; } } } #if BX_USE_QUICK_TLB_INVALIDATE BX_CPU_THIS_PTR TLB.tlb_invalidate = BX_MAX_TLB_INVALIDATE; #endif #endif // #if BX_USE_TLB } void BX_CPU_C::TLB_flush(bx_bool invalidateGlobal) { #if InstrumentTLB if (invalidateGlobal) InstrTLB_Increment(tlbGlobalFlushes); else InstrTLB_Increment(tlbNonGlobalFlushes); #endif #if BX_USE_TLB for (unsigned i=0; i= 4 Bit32u TLB_index; bx_address laddr; invalidate_prefetch_q(); // Operand must not be a register if (i->modC0()) { #if BX_SUPPORT_X86_64 if (BX_CPU_THIS_PTR cpu_mode == BX_MODE_LONG_64) { #ifdef __GNUC__ #warning PRT: check this is right. instruction is "0F 01 F8" see AMD manual. #endif if ((i->rm() == 0) && (i->nnn() == 7)) { BX_CPU_THIS_PTR SWAPGS(i); return; } } #endif BX_INFO(("INVLPG: op is a register")); UndefinedOpcode(i); } // Can not be executed in v8086 mode if (v8086_mode()) exception(BX_GP_EXCEPTION, 0, 0); // Protected instruction: CPL0 only if (BX_CPU_THIS_PTR cr0.pe) { if (CPL!=0) { BX_INFO(("INVLPG: CPL!=0")); exception(BX_GP_EXCEPTION, 0, 0); } } #if BX_USE_TLB laddr = BX_CPU_THIS_PTR sregs[i->seg()].cache.u.segment.base + RMAddr(i); TLB_index = BX_TLB_INDEX_OF(laddr); BX_CPU_THIS_PTR TLB.entry[TLB_index].lpf = BX_INVALID_TLB_ENTRY; InstrTLB_Increment(tlbEntryInvlpg); #endif // BX_USE_TLB BX_INSTR_TLB_CNTRL(BX_CPU_ID, BX_INSTR_INVLPG, 0); #else // not supported on < 486 UndefinedOpcode(i); #endif } // Translate a linear address to a physical address, for // a data access (D) Bit32u BX_CPP_AttrRegparmN(3) BX_CPU_C::dtranslate_linear(bx_address laddr, unsigned pl, unsigned rw) { bx_address lpf; Bit32u ppf, poffset, TLB_index, error_code, paddress; Bit32u pde, pde_addr; bx_bool isWrite; Bit32u accessBits, combined_access; unsigned priv_index; InstrTLB_Increment(tlbLookups); InstrTLB_Stats(); #if BX_SupportPAE if (BX_CPU_THIS_PTR cr4.get_PAE()) { Bit32u pdp, pdp_addr; lpf = laddr & BX_CONST64(0xfffffffffffff000); // linear page frame poffset = laddr & 0x00000fff; // physical offset TLB_index = BX_TLB_INDEX_OF(lpf); isWrite = (rw>=BX_WRITE); // write or r-m-w //BX_DEBUG (("poffset: %-8x laddr: %-8x lpf: %-8x",poffset,laddr,lpf)); if (BX_CPU_THIS_PTR TLB.entry[TLB_index].lpf == BX_TLB_LPF_VALUE(lpf)) { paddress = BX_CPU_THIS_PTR TLB.entry[TLB_index].ppf | poffset; accessBits = BX_CPU_THIS_PTR TLB.entry[TLB_index].accessBits; if (accessBits & (1 << ((isWrite<<1) | pl)) ) { return(paddress); } // The current access does not have permission according to the info // in our TLB cache entry. Re-walk the page tables, in case there is // updated information in the memory image, and let the long path code // generate an exception if one is warranted. } InstrTLB_Increment(tlbMisses); // note - we assume physical memory < 4gig so for brevity & speed, we'll use // 32 bit entries although cr3 is expanded to 64 bits. #if BX_SUPPORT_X86_64 if (BX_CPU_THIS_PTR msr.lma) { Bit32u pml4, pml4_addr; // Get PML4 entry pml4_addr = (BX_CPU_THIS_PTR cr3 & 0xfffff000) | ((laddr & BX_CONST64(0x0000ff8000000000)) >> 36); BX_CPU_THIS_PTR mem->readPhysicalPage(this, pml4_addr, 4, &pml4); if ( !(pml4 & 0x01) ) { // PML4 Entry NOT present error_code = 0x00000000; // RSVD=0, P=0 goto page_fault_not_present; } if ( !(pml4 & 0x20) ) { pml4 |= 0x20; BX_CPU_THIS_PTR mem->writePhysicalPage(this, pml4_addr, 4, &pml4); } // Get PDP entry pdp_addr = (pml4 & 0xfffff000) | ((laddr & BX_CONST64(0x0000007fc0000000)) >> 27); } else #endif { pdp_addr = (BX_CPU_THIS_PTR cr3 & 0xfffff000) | ((laddr & 0xc0000000) >> 27); } BX_CPU_THIS_PTR mem->readPhysicalPage(this, pdp_addr, 4, &pdp); if ( !(pdp & 0x01) ) { // PDP Entry NOT present error_code = 0x00000000; // RSVD=0, P=0 goto page_fault_not_present; } if ( !(pdp & 0x20) ) { pdp |= 0x20; BX_CPU_THIS_PTR mem->writePhysicalPage(this, pdp_addr, 4, &pdp); } // Get page dir entry pde_addr = (pdp & 0xfffff000) | ((laddr & 0x3fe00000) >> 18); BX_CPU_THIS_PTR mem->readPhysicalPage(this, pde_addr, 4, &pde); if ( !(pde & 0x01) ) { // Page Directory Entry NOT present error_code = 0x00000000; // RSVD=0, P=0 goto page_fault_not_present; } #if BX_SUPPORT_4MEG_PAGES // (KPL) Weird. I would think the processor would consult CR.PSE? // if ((pde & 0x80) && (BX_CPU_THIS_PTR cr4.get_PSE())) {} if (pde & 0x80) { // 4M pages are enabled, and this is a 4Meg page. // Combined access is just access from the pde (no pte involved). combined_access = pde & 0x06; // U/S and R/W // Make up the physical page frame address. ppf = (pde & 0xffe00000) | (laddr & 0x001ff000); #if BX_SupportGlobalPages if (BX_CPU_THIS_PTR cr4.get_PGE()) // PGE==1 combined_access |= (pde & 0x100); // G #endif priv_index = #if BX_CPU_LEVEL >= 4 (BX_CPU_THIS_PTR cr0.wp<<4) | // bit 4 #endif (pl<<3) | // bit 3 (combined_access & 0x06) | // bit 2,1 isWrite; // bit 0 if (!priv_check[priv_index]) { error_code = 0x00000001; // RSVD=0, P=1 goto page_fault_access; } // Update PDE if A/D bits if needed. if ( ((pde & 0x20)==0) || (isWrite && ((pde&0x40)==0)) ) { pde |= (0x20 | (isWrite<<6)); // Update A and possibly D bits BX_CPU_THIS_PTR mem->writePhysicalPage(this, pde_addr, 4, &pde); } } else #endif { // 4k pages. Bit32u pte, pte_addr; // Get page table entry pte_addr = (pde & 0xfffff000) | ((laddr & 0x001ff000) >> 9); BX_CPU_THIS_PTR mem->readPhysicalPage(this, pte_addr, 4, &pte); combined_access = (pde & pte) & 0x06; // U/S and R/W // Make up the physical page frame address. ppf = pte & 0xfffff000; #if BX_SupportGlobalPages if (BX_CPU_THIS_PTR cr4.get_PGE()) // PGE==1 combined_access |= (pte & 0x100); // G #endif if ( !(pte & 0x01) ) { // Page Table Entry NOT present error_code = 0x00000000; // RSVD=0, P=0 goto page_fault_not_present; } priv_index = #if BX_CPU_LEVEL >= 4 (BX_CPU_THIS_PTR cr0.wp<<4) | // bit 4 #endif (pl<<3) | // bit 3 (combined_access & 0x06) | // bit 2,1 isWrite; // bit 0 if (!priv_check[priv_index]) { error_code = 0x00000001; // RSVD=0, P=1 goto page_fault_access; } // Update PDE A bit if needed. if ( (pde & 0x20)==0 ) { pde |= 0x20; // Update A bit. BX_CPU_THIS_PTR mem->writePhysicalPage(this, pde_addr, 4, &pde); } // Update PTE A/D bits if needed. if ( ((pte & 0x20)==0) || (isWrite && ((pte&0x40)==0)) ) { pte |= (0x20 | (isWrite<<6)); // Update A and possibly D bits BX_CPU_THIS_PTR mem->writePhysicalPage(this, pte_addr, 4, &pte); } } // Calculate physical memory address and fill in TLB cache entry paddress = ppf | poffset; BX_CPU_THIS_PTR TLB.entry[TLB_index].lpf = lpf; BX_CPU_THIS_PTR TLB.entry[TLB_index].ppf = ppf; if ( combined_access & 4 ) { // User accessBits = 0x3; // User priv; read from {user,sys} OK. if ( isWrite ) { // Current operation is a write (Dirty bit updated) accessBits |= 0xc; // write from {user,sys} OK. } } else { // System accessBits = 0x1; // System priv; read from {sys} OK. if ( isWrite ) { // Current operation is a write (Dirty bit updated) accessBits |= 4; // write from {sys} OK. } } #if BX_SupportGlobalPages accessBits |= combined_access & 0x100; // Global bit #endif BX_CPU_THIS_PTR TLB.entry[TLB_index].accessBits = accessBits; #if BX_SupportGuest2HostTLB // Attempt to get a host pointer to this physical page. Put that // pointer in the TLB cache. Note if the request is vetoed, NULL // will be returned, and it's OK to OR zero in anyways. BX_CPU_THIS_PTR TLB.entry[TLB_index].hostPageAddr = (bx_hostpageaddr_t) BX_CPU_THIS_PTR mem->getHostMemAddr(this, A20ADDR(ppf), rw); #endif return(paddress); } #endif // #if BX_SupportPAE // CR4.PAE==0 (and MSR.LMA==0) lpf = laddr & 0xfffff000; // linear page frame poffset = laddr & 0x00000fff; // physical offset TLB_index = BX_TLB_INDEX_OF(lpf); isWrite = (rw>=BX_WRITE); // write or r-m-w if (BX_CPU_THIS_PTR TLB.entry[TLB_index].lpf == BX_TLB_LPF_VALUE(lpf)) { paddress = BX_CPU_THIS_PTR TLB.entry[TLB_index].ppf | poffset; accessBits = BX_CPU_THIS_PTR TLB.entry[TLB_index].accessBits; if (accessBits & (1 << ((isWrite<<1) | pl)) ) { return(paddress); } // The current access does not have permission according to the info // in our TLB cache entry. Re-walk the page tables, in case there is // updated information in the memory image, and let the long path code // generate an exception if one is warranted. } InstrTLB_Increment(tlbMisses); // Get page dir entry pde_addr = (BX_CPU_THIS_PTR cr3 & 0xfffff000) | ((laddr & 0xffc00000) >> 20); BX_CPU_THIS_PTR mem->readPhysicalPage(this, pde_addr, 4, &pde); if ( !(pde & 0x01) ) { // Page Directory Entry NOT present error_code = 0x00000000; // RSVD=0, P=0 goto page_fault_not_present; } #if BX_SUPPORT_4MEG_PAGES if ((pde & 0x80) && (BX_CPU_THIS_PTR cr4.get_PSE())) { // 4M pages are enabled, and this is a 4Meg page. // Note: when the PSE and PAE flags in CR4 are set, // the processor generates a PF if the reserved bits are not // set to 0. (We don't handle PAE yet, just a note for // the future). // Combined access is just access from the pde (no pte involved). combined_access = pde & 0x006; // {US,RW} // make up the physical frame number ppf = (pde & 0xFFC00000) | (laddr & 0x003FF000); #if BX_SupportGlobalPages if (BX_CPU_THIS_PTR cr4.get_PGE()) // PGE==1 combined_access |= pde & 0x100; // {G} #endif priv_index = #if BX_CPU_LEVEL >= 4 (BX_CPU_THIS_PTR cr0.wp<<4) | // bit 4 #endif (pl<<3) | // bit 3 (combined_access & 0x06) | // bit 2,1 isWrite; // bit 0 if (!priv_check[priv_index]) { error_code = 0x00000001; // RSVD=0, P=1 goto page_fault_access; } // Update PDE if A/D bits if needed. if ( ((pde & 0x20)==0) || (isWrite && ((pde&0x40)==0)) ) { pde |= (0x20 | (isWrite<<6)); // Update A and possibly D bits BX_CPU_THIS_PTR mem->writePhysicalPage(this, pde_addr, 4, &pde); } } // Else normal 4Kbyte page... else #endif { Bit32u pte, pte_addr; #if (BX_CPU_LEVEL < 6) // update PDE if A bit was not set before if ( !(pde & 0x20) ) { pde |= 0x20; BX_CPU_THIS_PTR mem->writePhysicalPage(this, pde_addr, 4, &pde); } #endif // Get page table entry pte_addr = (pde & 0xfffff000) | ((laddr & 0x003ff000) >> 10); BX_CPU_THIS_PTR mem->readPhysicalPage(this, pte_addr, 4, &pte); // 386 and 486+ have different bahaviour for combining // privilege from PDE and PTE. #if BX_CPU_LEVEL == 3 combined_access = (pde | pte) & 0x04; // U/S combined_access |= (pde & pte) & 0x02; // R/W #else // 486+ combined_access = (pde & pte) & 0x06; // U/S and R/W #if BX_SupportGlobalPages if (BX_CPU_THIS_PTR cr4.get_PGE()) combined_access |= (pte & 0x100); // G #endif #endif // Make up the physical page frame address. ppf = pte & 0xfffff000; if ( !(pte & 0x01) ) { // Page Table Entry NOT present error_code = 0x00000000; // RSVD=0, P=0 goto page_fault_not_present; } priv_index = #if BX_CPU_LEVEL >= 4 (BX_CPU_THIS_PTR cr0.wp<<4) | // bit 4 #endif (pl<<3) | // bit 3 (combined_access & 0x06) | // bit 2,1 isWrite; // bit 0 if (!priv_check[priv_index]) { error_code = 0x00000001; // RSVD=0, P=1 goto page_fault_access; } #if (BX_CPU_LEVEL >= 6) // update PDE if A bit was not set before if ( !(pde & 0x20) ) { pde |= 0x20; BX_CPU_THIS_PTR mem->writePhysicalPage(this, pde_addr, 4, &pde); } #endif // Update PTE if A/D bits if needed. if ( ((pte & 0x20)==0) || (isWrite && ((pte&0x40)==0)) ) { pte |= (0x20 | (isWrite<<6)); // Update A and possibly D bits BX_CPU_THIS_PTR mem->writePhysicalPage(this, pte_addr, 4, &pte); } } // Calculate physical memory address and fill in TLB cache entry paddress = ppf | poffset; BX_CPU_THIS_PTR TLB.entry[TLB_index].lpf = BX_TLB_LPF_VALUE(lpf); BX_CPU_THIS_PTR TLB.entry[TLB_index].ppf = ppf; // 1 << ((W<<1) | U) // b0: Read Sys OK // b1: Read User OK // b2: Write Sys OK // b3: Write User OK if ( combined_access & 4 ) { // User accessBits = 0x3; // User priv; read from {user,sys} OK. if ( isWrite ) { // Current operation is a write (Dirty bit updated) accessBits |= 0xc; // write from {user,sys} OK. } } else { // System accessBits = 0x1; // System priv; read from {sys} OK. if ( isWrite ) { // Current operation is a write (Dirty bit updated) accessBits |= 4; // write from {sys} OK. } } #if BX_SupportGlobalPages accessBits |= combined_access & 0x100; // Global bit #endif BX_CPU_THIS_PTR TLB.entry[TLB_index].accessBits = accessBits; #if BX_SupportGuest2HostTLB // Attempt to get a host pointer to this physical page. Put that // pointer in the TLB cache. Note if the request is vetoed, NULL // will be returned, and it's OK to OR zero in anyways. BX_CPU_THIS_PTR TLB.entry[TLB_index].hostPageAddr = (bx_hostpageaddr_t) BX_CPU_THIS_PTR mem->getHostMemAddr(this, A20ADDR(ppf), rw); #endif return(paddress); page_fault_access: page_fault_not_present: error_code |= (pl << 2) | (isWrite << 1); BX_CPU_THIS_PTR cr2 = laddr; // Invalidate TLB entry. BX_CPU_THIS_PTR TLB.entry[TLB_index].lpf = BX_INVALID_TLB_ENTRY; #if BX_EXTERNAL_DEBUGGER #if BX_SUPPORT_X86_64 printf("page fault for address %08x%08x @ %08x%08x\n", (Bit32u)(laddr >> 32),(Bit32u)(laddr & 0xffffffff), (Bit32u)(RIP >> 32),(Bit32u)(RIP & 0xffffffff)); #else //printf("page fault for address %08x\n",laddr); #endif #endif exception(BX_PF_EXCEPTION, error_code, 0); return(0); // keep compiler happy } // Translate a linear address to a physical address, for // an instruction fetch access (I) Bit32u BX_CPP_AttrRegparmN(2) BX_CPU_C::itranslate_linear(bx_address laddr, unsigned pl) { return dtranslate_linear(laddr, pl, BX_READ); } #if BX_DEBUGGER || BX_DISASM || BX_INSTRUMENTATION || BX_GDBSTUB #if BX_SUPPORT_X86_64 #ifdef __GNUC__ #warning "Fix dbg_xlate_linear2phy for 64-bit and new features." #endif #endif void BX_CPU_C::dbg_xlate_linear2phy(Bit32u laddr, Bit32u *phy, bx_bool *valid) { Bit32u lpf, ppf, poffset, TLB_index, paddress; Bit32u pde, pde_addr; Bit32u pte, pte_addr; if (BX_CPU_THIS_PTR cr0.pg == 0) { *phy = laddr; *valid = 1; return; } lpf = laddr & 0xfffff000; // linear page frame poffset = laddr & 0x00000fff; // physical offset TLB_index = BX_TLB_INDEX_OF(lpf); // see if page is in the TLB first if (BX_CPU_THIS_PTR TLB.entry[TLB_index].lpf == BX_TLB_LPF_VALUE(lpf)) { paddress = BX_CPU_THIS_PTR TLB.entry[TLB_index].ppf | poffset; *phy = paddress; *valid = 1; return; } // Get page dir entry pde_addr = (BX_CPU_THIS_PTR cr3 & 0xfffff000) | ((laddr & 0xffc00000) >> 20); BX_CPU_THIS_PTR mem->readPhysicalPage(this, pde_addr, 4, &pde); if ( !(pde & 0x01) ) { // Page Directory Entry NOT present goto page_fault; } // Get page table entry pte_addr = (pde & 0xfffff000) | ((laddr & 0x003ff000) >> 10); BX_CPU_THIS_PTR mem->readPhysicalPage(this, pte_addr, 4, &pte); if ( !(pte & 0x01) ) { // Page Table Entry NOT present goto page_fault; } ppf = pte & 0xfffff000; paddress = ppf | poffset; *phy = paddress; *valid = 1; return; page_fault: *phy = 0; *valid = 0; return; } #endif void BX_CPP_AttrRegparmN(3) BX_CPU_C::access_linear(bx_address laddr, unsigned length, unsigned pl, unsigned rw, void *data) { Bit32u pageOffset; unsigned xlate_rw; #if BX_X86_DEBUGGER if ( BX_CPU_THIS_PTR dr7 & 0x000000ff ) { // Only compare debug registers if any breakpoints are enabled Bit32u dr6_bits; unsigned opa, opb; opa = BX_HWDebugMemRW; // Read or Write always compares vs 11b if (rw==BX_READ) // only compares vs 11b opb = opa; else // BX_WRITE or BX_RW; also compare vs 01b opb = BX_HWDebugMemW; dr6_bits = hwdebug_compare(laddr, length, opa, opb); if (dr6_bits) { BX_CPU_THIS_PTR debug_trap |= dr6_bits; BX_CPU_THIS_PTR async_event = 1; } } #endif if (rw==BX_RW) { xlate_rw = BX_RW; rw = BX_READ; } else { xlate_rw = rw; } pageOffset = laddr & 0x00000fff; if (BX_CPU_THIS_PTR cr0.pg) { /* check for reference across multiple pages */ if ( (pageOffset + length) <= 4096 ) { // Access within single page. BX_CPU_THIS_PTR address_xlation.paddress1 = dtranslate_linear(laddr, pl, xlate_rw); BX_CPU_THIS_PTR address_xlation.pages = 1; if (rw == BX_READ) { BX_INSTR_LIN_READ(BX_CPU_ID, laddr, BX_CPU_THIS_PTR address_xlation.paddress1, length); BX_CPU_THIS_PTR mem->readPhysicalPage(this, BX_CPU_THIS_PTR address_xlation.paddress1, length, data); } else { BX_INSTR_LIN_WRITE(BX_CPU_ID, laddr, BX_CPU_THIS_PTR address_xlation.paddress1, length); BX_CPU_THIS_PTR mem->writePhysicalPage(this, BX_CPU_THIS_PTR address_xlation.paddress1, length, data); } return; } else { // access across 2 pages BX_CPU_THIS_PTR address_xlation.paddress1 = dtranslate_linear(laddr, pl, xlate_rw); BX_CPU_THIS_PTR address_xlation.len1 = 4096 - pageOffset; BX_CPU_THIS_PTR address_xlation.len2 = length - BX_CPU_THIS_PTR address_xlation.len1; BX_CPU_THIS_PTR address_xlation.pages = 2; BX_CPU_THIS_PTR address_xlation.paddress2 = dtranslate_linear(laddr + BX_CPU_THIS_PTR address_xlation.len1, pl, xlate_rw); #ifdef BX_LITTLE_ENDIAN if (rw == BX_READ) { BX_INSTR_LIN_READ(BX_CPU_ID, laddr, BX_CPU_THIS_PTR address_xlation.paddress1, BX_CPU_THIS_PTR address_xlation.len1); BX_CPU_THIS_PTR mem->readPhysicalPage(this, BX_CPU_THIS_PTR address_xlation.paddress1, BX_CPU_THIS_PTR address_xlation.len1, data); BX_INSTR_LIN_READ(BX_CPU_ID, laddr + BX_CPU_THIS_PTR address_xlation.len1, BX_CPU_THIS_PTR address_xlation.paddress2, BX_CPU_THIS_PTR address_xlation.len2); BX_CPU_THIS_PTR mem->readPhysicalPage(this, BX_CPU_THIS_PTR address_xlation.paddress2, BX_CPU_THIS_PTR address_xlation.len2, ((Bit8u*)data) + BX_CPU_THIS_PTR address_xlation.len1); } else { BX_INSTR_LIN_WRITE(BX_CPU_ID, laddr, BX_CPU_THIS_PTR address_xlation.paddress1, BX_CPU_THIS_PTR address_xlation.len1); BX_CPU_THIS_PTR mem->writePhysicalPage(this, BX_CPU_THIS_PTR address_xlation.paddress1, BX_CPU_THIS_PTR address_xlation.len1, data); BX_INSTR_LIN_WRITE(BX_CPU_ID, laddr + BX_CPU_THIS_PTR address_xlation.len1, BX_CPU_THIS_PTR address_xlation.paddress2, BX_CPU_THIS_PTR address_xlation.len2); BX_CPU_THIS_PTR mem->writePhysicalPage(this, BX_CPU_THIS_PTR address_xlation.paddress2, BX_CPU_THIS_PTR address_xlation.len2, ((Bit8u*)data) + BX_CPU_THIS_PTR address_xlation.len1); } #else // BX_BIG_ENDIAN if (rw == BX_READ) { BX_INSTR_LIN_READ(BX_CPU_ID, laddr, BX_CPU_THIS_PTR address_xlation.paddress1, BX_CPU_THIS_PTR address_xlation.len1); BX_CPU_THIS_PTR mem->readPhysicalPage(this, BX_CPU_THIS_PTR address_xlation.paddress1, BX_CPU_THIS_PTR address_xlation.len1, ((Bit8u*)data) + (length - BX_CPU_THIS_PTR address_xlation.len1)); BX_INSTR_LIN_READ(BX_CPU_ID, laddr + BX_CPU_THIS_PTR address_xlation.len1, BX_CPU_THIS_PTR address_xlation.paddress2, BX_CPU_THIS_PTR address_xlation.len2); BX_CPU_THIS_PTR mem->readPhysicalPage(this, BX_CPU_THIS_PTR address_xlation.paddress2, BX_CPU_THIS_PTR address_xlation.len2, data); } else { BX_INSTR_LIN_WRITE(BX_CPU_ID, laddr, BX_CPU_THIS_PTR address_xlation.paddress1, BX_CPU_THIS_PTR address_xlation.len1); BX_CPU_THIS_PTR mem->writePhysicalPage(this, BX_CPU_THIS_PTR address_xlation.paddress1, BX_CPU_THIS_PTR address_xlation.len1, ((Bit8u*)data) + (length - BX_CPU_THIS_PTR address_xlation.len1)); BX_INSTR_LIN_WRITE(BX_CPU_ID, laddr + BX_CPU_THIS_PTR address_xlation.len1, BX_CPU_THIS_PTR address_xlation.paddress2, BX_CPU_THIS_PTR address_xlation.len2); BX_CPU_THIS_PTR mem->writePhysicalPage(this, BX_CPU_THIS_PTR address_xlation.paddress2, BX_CPU_THIS_PTR address_xlation.len2, data); } #endif return; } } else { // Paging off. if ( (pageOffset + length) <= 4096 ) { // Access within single page. BX_CPU_THIS_PTR address_xlation.paddress1 = laddr; BX_CPU_THIS_PTR address_xlation.pages = 1; if (rw == BX_READ) { #if BX_SupportGuest2HostTLB Bit32u lpf, tlbIndex; #endif BX_INSTR_LIN_READ(BX_CPU_ID, laddr, laddr, length); #if BX_SupportGuest2HostTLB tlbIndex = BX_TLB_INDEX_OF(laddr); lpf = laddr & 0xfffff000; if (BX_CPU_THIS_PTR TLB.entry[tlbIndex].lpf == BX_TLB_LPF_VALUE(lpf)) { BX_CPU_THIS_PTR mem->readPhysicalPage(this, laddr, length, data); return; } // We haven't seen this page, or it's been bumped before. BX_CPU_THIS_PTR TLB.entry[tlbIndex].lpf = BX_TLB_LPF_VALUE(lpf); BX_CPU_THIS_PTR TLB.entry[tlbIndex].ppf = lpf; // Request a direct write pointer so we can do either R or W. BX_CPU_THIS_PTR TLB.entry[tlbIndex].hostPageAddr = (bx_hostpageaddr_t) BX_CPU_THIS_PTR mem->getHostMemAddr(this, A20ADDR(lpf), BX_WRITE); if (!BX_CPU_THIS_PTR TLB.entry[tlbIndex].hostPageAddr) { // Direct write vetoed. Try requesting only direct reads. BX_CPU_THIS_PTR TLB.entry[tlbIndex].hostPageAddr = (bx_hostpageaddr_t) BX_CPU_THIS_PTR mem->getHostMemAddr(this, A20ADDR(lpf), BX_READ); if (BX_CPU_THIS_PTR TLB.entry[tlbIndex].hostPageAddr) { // Got direct read pointer OK. BX_CPU_THIS_PTR TLB.entry[tlbIndex].accessBits = (ReadSysOK | ReadUserOK); } else BX_CPU_THIS_PTR TLB.entry[tlbIndex].accessBits = 0; } else { // Got direct write pointer OK. Mark for any operation to succeed. BX_CPU_THIS_PTR TLB.entry[tlbIndex].accessBits = (ReadSysOK | ReadUserOK | WriteSysOK | WriteUserOK); } #endif // BX_SupportGuest2HostTLB // Let access fall through to the following for this iteration. BX_CPU_THIS_PTR mem->readPhysicalPage(this, laddr, length, data); } else { // Write #if BX_SupportGuest2HostTLB Bit32u lpf, tlbIndex; #endif BX_INSTR_LIN_WRITE(BX_CPU_ID, laddr, laddr, length); #if BX_SupportGuest2HostTLB tlbIndex = BX_TLB_INDEX_OF(laddr); lpf = laddr & 0xfffff000; if (BX_CPU_THIS_PTR TLB.entry[tlbIndex].lpf == BX_TLB_LPF_VALUE(lpf)) { BX_CPU_THIS_PTR mem->writePhysicalPage(this, laddr, length, data); return; } // We haven't seen this page, or it's been bumped before. BX_CPU_THIS_PTR TLB.entry[tlbIndex].lpf = BX_TLB_LPF_VALUE(lpf); BX_CPU_THIS_PTR TLB.entry[tlbIndex].ppf = lpf; // TLB.entry[tlbIndex].ppf field not used for PG==0. // Request a direct write pointer so we can do either R or W. BX_CPU_THIS_PTR TLB.entry[tlbIndex].hostPageAddr = (bx_hostpageaddr_t) BX_CPU_THIS_PTR mem->getHostMemAddr(this, A20ADDR(lpf), BX_WRITE); if (BX_CPU_THIS_PTR TLB.entry[tlbIndex].hostPageAddr) { // Got direct write pointer OK. Mark for any operation to succeed. BX_CPU_THIS_PTR TLB.entry[tlbIndex].accessBits = (ReadSysOK | ReadUserOK | WriteSysOK | WriteUserOK); } else BX_CPU_THIS_PTR TLB.entry[tlbIndex].accessBits = 0; #endif // BX_SupportGuest2HostTLB BX_CPU_THIS_PTR mem->writePhysicalPage(this, laddr, length, data); } } else { // Access spans two pages. BX_CPU_THIS_PTR address_xlation.paddress1 = laddr; BX_CPU_THIS_PTR address_xlation.len1 = 4096 - pageOffset; BX_CPU_THIS_PTR address_xlation.len2 = length - BX_CPU_THIS_PTR address_xlation.len1; BX_CPU_THIS_PTR address_xlation.pages = 2; BX_CPU_THIS_PTR address_xlation.paddress2 = laddr + BX_CPU_THIS_PTR address_xlation.len1; #ifdef BX_LITTLE_ENDIAN if (rw == BX_READ) { BX_INSTR_LIN_READ(BX_CPU_ID, laddr, BX_CPU_THIS_PTR address_xlation.paddress1, BX_CPU_THIS_PTR address_xlation.len1); BX_CPU_THIS_PTR mem->readPhysicalPage(this, BX_CPU_THIS_PTR address_xlation.paddress1, BX_CPU_THIS_PTR address_xlation.len1, data); BX_INSTR_LIN_READ(BX_CPU_ID, laddr + BX_CPU_THIS_PTR address_xlation.len1, BX_CPU_THIS_PTR address_xlation.paddress2, BX_CPU_THIS_PTR address_xlation.len2); BX_CPU_THIS_PTR mem->readPhysicalPage(this, BX_CPU_THIS_PTR address_xlation.paddress2, BX_CPU_THIS_PTR address_xlation.len2, ((Bit8u*)data) + BX_CPU_THIS_PTR address_xlation.len1); } else { BX_INSTR_LIN_WRITE(BX_CPU_ID, laddr, BX_CPU_THIS_PTR address_xlation.paddress1, BX_CPU_THIS_PTR address_xlation.len1); BX_CPU_THIS_PTR mem->writePhysicalPage(this, BX_CPU_THIS_PTR address_xlation.paddress1, BX_CPU_THIS_PTR address_xlation.len1, data); BX_INSTR_LIN_WRITE(BX_CPU_ID, laddr + BX_CPU_THIS_PTR address_xlation.len1, BX_CPU_THIS_PTR address_xlation.paddress2, BX_CPU_THIS_PTR address_xlation.len2); BX_CPU_THIS_PTR mem->writePhysicalPage(this, BX_CPU_THIS_PTR address_xlation.paddress2, BX_CPU_THIS_PTR address_xlation.len2, ((Bit8u*)data) + BX_CPU_THIS_PTR address_xlation.len1); } #else // BX_BIG_ENDIAN if (rw == BX_READ) { BX_INSTR_LIN_READ(BX_CPU_ID, laddr, BX_CPU_THIS_PTR address_xlation.paddress1, BX_CPU_THIS_PTR address_xlation.len1); BX_CPU_THIS_PTR mem->readPhysicalPage(this, BX_CPU_THIS_PTR address_xlation.paddress1, BX_CPU_THIS_PTR address_xlation.len1, ((Bit8u*)data) + (length - BX_CPU_THIS_PTR address_xlation.len1)); BX_INSTR_LIN_READ(BX_CPU_ID, laddr + BX_CPU_THIS_PTR address_xlation.len1, BX_CPU_THIS_PTR address_xlation.paddress2, BX_CPU_THIS_PTR address_xlation.len2); BX_CPU_THIS_PTR mem->readPhysicalPage(this, BX_CPU_THIS_PTR address_xlation.paddress2, BX_CPU_THIS_PTR address_xlation.len2, data); } else { BX_INSTR_LIN_WRITE(BX_CPU_ID, laddr, BX_CPU_THIS_PTR address_xlation.paddress1, BX_CPU_THIS_PTR address_xlation.len1); BX_CPU_THIS_PTR mem->writePhysicalPage(this, BX_CPU_THIS_PTR address_xlation.paddress1, BX_CPU_THIS_PTR address_xlation.len1, ((Bit8u*)data) + (length - BX_CPU_THIS_PTR address_xlation.len1)); BX_INSTR_LIN_WRITE(BX_CPU_ID, laddr + BX_CPU_THIS_PTR address_xlation.len1, BX_CPU_THIS_PTR address_xlation.paddress2, BX_CPU_THIS_PTR address_xlation.len2); BX_CPU_THIS_PTR mem->writePhysicalPage(this, BX_CPU_THIS_PTR address_xlation.paddress2, BX_CPU_THIS_PTR address_xlation.len2, data); } #endif } return; } } #else // BX_SUPPORT_PAGING // stub functions for non-support of paging void BX_CPU_C::enable_paging(void) { BX_PANIC(("enable_paging(): not implemented")); } void BX_CPU_C::disable_paging(void) { BX_PANIC(("disable_paging() called")); } void BX_CPU_C::CR3_change(Bit32u value32) { BX_INFO(("CR3_change(): flush TLB cache")); BX_INFO(("Page Directory Base %08x", (unsigned) value32)); } void BX_CPU_C::access_linear(Bit32u laddr, unsigned length, unsigned pl, unsigned rw, void *data) { /* perhaps put this check before all code which calls this function, * so we don't have to here */ if (BX_CPU_THIS_PTR cr0.pg == 0) { if (rw == BX_READ) BX_CPU_THIS_PTR mem->readPhysicalPage(this, laddr, length, data); else BX_CPU_THIS_PTR mem->writePhysicalPage(this, laddr, length, data); return; } BX_PANIC(("access_linear: paging not supported")); } void BX_CPU_C::INVLPG(bxInstruction_c* i) {} #endif // BX_SUPPORT_PAGING