///////////////////////////////////////////////////////////////////////// // $Id: paging.cc,v 1.13 2002-09-05 02:31:24 kevinlawton 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 #if 0 // - what should the reserved bits in the error code be ? #endif #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_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 // // The TLB cache holds the following info, from which the above // fields can efficiently be extracted to facilitate a privilege check: // // |4 |3 |2 |1 |0 | // | | |us|rw|D | // | | | // | | +---> Dirty bit from PTE (not used for privilege check) // +--+------> u/s,r/w combined of page dir & table // // // The rest of the fields are taken from current access parameters // and the write-protect field: // // |4 |3 |2 |1 |0 | // |wp|us| | |rw| // | | | // | | +---> r/w of current access // | | // | +------------> u/s of current access // +---------------> Current CR0.wp value #define ReadSysOK 0x01 #define ReadUserOK 0x02 #define WriteSysOK 0x04 #define WriteUserOK 0x08 #define AccessBitsRVetoed 0x10 #define AccessBitsWVetoed 0x20 #ifndef _MSC_VER // MSC++ doesn't understand a #warning #warning "Move priv_check to CPU fields, or init.cc" #endif static unsigned priv_check[BX_PRIV_CHECK_SIZE]; void BX_CPU_C::enable_paging(void) { TLB_flush(); if (bx_dbg.paging) BX_INFO(("enable_paging():")); //BX_DEBUG(( "enable_paging():-------------------------" )); } void BX_CPU_C::disable_paging(void) { TLB_flush(); if (bx_dbg.paging) BX_INFO(("disable_paging():")); } void BX_CPU_C::CR3_change(Bit32u value32) { if (bx_dbg.paging) { BX_INFO(("CR3_change(): flush TLB cache")); BX_INFO(("Page Directory Base %08x", (unsigned) value32)); } // flush TLB even if value does not change TLB_flush(); BX_CPU_THIS_PTR cr3 = value32; } void BX_CPU_C::pagingWPChanged(void) { // Since our TLB contains markings dependent on the previous value // of CR0.WP, clear the cache and start over. TLB_clear(); #ifndef _MSC_VER #warning "duplicate with disable_paging etc?" // maybe just do pagingCR0Changed() #endif } void BX_CPU_C::pagingA20Changed(void) { TLB_clear(); } 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; } } } #endif // #if BX_USE_TLB } void BX_CPU_C::TLB_flush(void) { #if BX_USE_TLB for (unsigned i=0; i= 4 invalidate_prefetch_q(); // Operand must not be a register if (i->mod == 0xc0) { 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 // Just clear the entire TLB, ugh! TLB_clear(); #endif // BX_USE_TLB BX_INSTR_TLB_CNTRL(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_CPU_C::dtranslate_linear(Bit32u laddr, unsigned pl, unsigned rw) { Bit32u lpf, ppf, poffset, TLB_index, error_code, paddress; Bit32u pde, pde_addr; Boolean isWrite; Bit32u accessBits, combined_access; unsigned priv_index; 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 == 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. goto pageTableWalk; // for clarity and in case of future mods } pageTableWalk: // 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 4M pages are enabled, and this is a 4Meg page if ((pde & 0x80) && (BX_CPU_THIS_PTR cr4 & 0x10)) { // 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 & 0x06; 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; } // make up the physical frame number ppf = (pde & 0xFFC00000) | (laddr & 0x003FF000); // 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); if ( !(pte & 0x01) ) { // Page Table Entry NOT present error_code = 0x00000000; // RSVD=0, P=0 goto page_fault_not_present; } // 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 #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; } ppf = pte & 0xfffff000; #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 = 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. } } 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].accessBits |= (Bit32u) BX_CPU_THIS_PTR mem->getHostMemAddr(A20ADDR(ppf), rw); #endif // BX_SupportGuest2HostTLB 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; 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_CPU_C::itranslate_linear(Bit32u laddr, unsigned pl) { Bit32u lpf, ppf, poffset, TLB_index, error_code, paddress; Bit32u pde, pde_addr; Bit32u accessBits, combined_access; unsigned priv_index; lpf = laddr & 0xfffff000; // linear page frame poffset = laddr & 0x00000fff; // physical offset TLB_index = BX_TLB_INDEX_OF(lpf); if (BX_CPU_THIS_PTR TLB.entry[TLB_index].lpf == 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 << 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. goto pageTableWalk; // for clarity and in case of future mods } pageTableWalk: // 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 4M pages are enabled, and this is a 4Meg page if ((pde & 0x80) && (BX_CPU_THIS_PTR cr4 & 0x10)) { // combined access is just access from the pde (no pte involved). combined_access = pde & 0x06; 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 // bit 0 always 0 (fetch==read) if (!priv_check[priv_index]) { error_code = 0x00000001; // RSVD=0, P=1 goto page_fault_access; } // make up the physical frame number ppf = (pde & 0xFFC00000) | (laddr & 0x003FF000); // Update PDE if A/D bits if needed. if ( (pde & 0x20)==0 ) { pde |= 0x20; // 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); if ( !(pte & 0x01) ) { // Page Table Entry NOT present error_code = 0x00000000; // RSVD=0, P=0 goto page_fault_not_present; } // 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 #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 // bit 0 always 0 (fetch==read) if (!priv_check[priv_index]) { error_code = 0x00000001; // RSVD=0, P=1 goto page_fault_access; } ppf = pte & 0xfffff000; #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 ) { pte |= 0x20; // 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; // 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. } else { // System accessBits = 0x1; // System priv; read from {sys} OK. } BX_CPU_THIS_PTR TLB.entry[TLB_index].accessBits = accessBits; #if BX_SupportGuest2HostTLB BX_CPU_THIS_PTR TLB.entry[TLB_index].accessBits |= (Bit32u) BX_CPU_THIS_PTR mem->getHostMemAddr(A20ADDR(ppf), BX_READ); #endif // BX_SupportGuest2HostTLB return(paddress); page_fault_access: page_fault_not_present: error_code |= (pl << 2); BX_CPU_THIS_PTR cr2 = laddr; // Invalidate TLB entry. BX_CPU_THIS_PTR TLB.entry[TLB_index].lpf = BX_INVALID_TLB_ENTRY; exception(BX_PF_EXCEPTION, error_code, 0); return(0); // keep compiler happy } #if BX_DEBUGGER || BX_DISASM || BX_INSTRUMENTATION void BX_CPU_C::dbg_xlate_linear2phy(Bit32u laddr, Bit32u *phy, Boolean *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 == 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_CPU_C::access_linear(Bit32u 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(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(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(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(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(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(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(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(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(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(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) { Bit32u lpf, tlbIndex; BX_INSTR_LIN_READ(laddr, laddr, length); #if BX_SupportGuest2HostTLB tlbIndex = BX_TLB_INDEX_OF(laddr); lpf = laddr & 0xfffff000; if (BX_CPU_THIS_PTR TLB.entry[tlbIndex].lpf == 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 = 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].accessBits = (Bit32u) BX_CPU_THIS_PTR mem->getHostMemAddr(A20ADDR(lpf), BX_WRITE); if (!BX_CPU_THIS_PTR TLB.entry[tlbIndex].accessBits) { // Direct write vetoed. Try requesting only direct reads. BX_CPU_THIS_PTR TLB.entry[tlbIndex].accessBits = (Bit32u) BX_CPU_THIS_PTR mem->getHostMemAddr(A20ADDR(lpf), BX_READ); if (!BX_CPU_THIS_PTR TLB.entry[tlbIndex].accessBits) { // No permissions, both R & W direct accesses vetoed. Accesses // will fall through to this function always. BX_CPU_THIS_PTR TLB.entry[tlbIndex].accessBits = (AccessBitsWVetoed | AccessBitsRVetoed); } else { // Got direct read pointer OK. BX_CPU_THIS_PTR TLB.entry[tlbIndex].accessBits |= (ReadSysOK | ReadUserOK); } } 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 Bit32u lpf, tlbIndex; BX_INSTR_LIN_WRITE(laddr, laddr, length); #if BX_SupportGuest2HostTLB tlbIndex = BX_TLB_INDEX_OF(laddr); lpf = laddr & 0xfffff000; if (BX_CPU_THIS_PTR TLB.entry[tlbIndex].lpf == 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 = 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].accessBits = (Bit32u) BX_CPU_THIS_PTR mem->getHostMemAddr(A20ADDR(lpf), BX_WRITE); if (!BX_CPU_THIS_PTR TLB.entry[tlbIndex].accessBits) { // Direct write vetoed. Try requesting only direct reads. BX_CPU_THIS_PTR TLB.entry[tlbIndex].accessBits = (AccessBitsWVetoed | AccessBitsRVetoed); } 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 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(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(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(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(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(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(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(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(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_t* i) {} #endif // BX_SUPPORT_PAGING