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Add 4MB page handling to InitPage and FOIL (dirty bit) handling
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@joncampbell123
joncampbell123 committed Dec 15, 2024
1 parent 887d29a commit 0bc5b7d
Showing 1 changed file with 131 additions and 86 deletions.
217 changes: 131 additions & 86 deletions src/cpu/paging.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -229,6 +229,7 @@ static inline PhysPt GetPageDirectoryEntryAddr(PhysPt lin_addr) {
static inline PhysPt GetPageTableEntryAddr(PhysPt lin_addr, const X86PageEntry& dir_entry) {
return ((PhysPt)dir_entry.dirblock.base << (PhysPt)12U) | ((lin_addr >> 10U) & 0xffcu);
}

/*
void PrintPageInfo(const char* string, PhysPt lin_addr, bool writing, bool prepare_only) {
Expand Down Expand Up @@ -350,38 +351,47 @@ class PageFoilHandler : public PageHandler {
X86PageEntry dir_entry, table_entry;

PhysPt dirEntryAddr = GetPageDirectoryEntryAddr(addr);
dir_entry.load=phys_readd(dirEntryAddr);
dir_entry.load = phys_readd(dirEntryAddr);
if (!dir_entry.dirblock.p) E_Exit("Undesired situation 1 in page foiler.");

PhysPt tableEntryAddr = GetPageTableEntryAddr(addr, dir_entry);
table_entry.load=phys_readd(tableEntryAddr);
if (!table_entry.block.p) E_Exit("Undesired situation 2 in page foiler.");
if (do_pse && dir_entry.dirblock.ps) {
// for debugging...
if (((dir_entry.dirblock4mb.base22<<10u)|(lin_page&0x3FFu)) != phys_page)
E_Exit("Undesired situation 3 PSE in page foiler.");

// for debugging...
if (table_entry.block.base != phys_page)
E_Exit("Undesired situation 3 in page foiler.");
// set the dirty bit
dir_entry.block.d=1;
phys_writed(dirEntryAddr,dir_entry.load);
}
else {
PhysPt tableEntryAddr = GetPageTableEntryAddr(addr, dir_entry);
table_entry.load=phys_readd(tableEntryAddr);
if (!table_entry.block.p) E_Exit("Undesired situation 2 in page foiler.");

// for debugging...
if (table_entry.block.base != phys_page)
E_Exit("Undesired situation 3 in page foiler.");

// debug
// LOG_MSG("FOIL LIN% 8x PHYS% 8x [%x/%x/%x] WRP % 8x", addr, phys_page,
// dirEntryAddr, tableEntryAddr, table_entry.load, wtest);

// this can happen when the same page table is used at two different
// page directory entries / linear locations (WfW311)
// if (table_entry.block.d) E_Exit("% 8x Already dirty!!",table_entry.load);

// set the dirty bit
table_entry.block.d=1;
phys_writed(tableEntryAddr,table_entry.load);
}

// map the real write handler in our place
PageHandler* handler = MEM_GetPageHandler(phys_page);

// debug
// LOG_MSG("FOIL LIN% 8x PHYS% 8x [%x/%x/%x] WRP % 8x", addr, phys_page,
// dirEntryAddr, tableEntryAddr, table_entry.load, wtest);

// this can happen when the same page table is used at two different
// page directory entries / linear locations (WfW311)
// if (table_entry.block.d) E_Exit("% 8x Already dirty!!",table_entry.load);


// set the dirty bit
table_entry.block.d=1;
phys_writed(tableEntryAddr,table_entry.load);

// replace this handler with the real thing
if (handler->getFlags() & PFLAG_WRITEABLE)
paging.tlb.write[lin_page] = handler->GetHostWritePt(phys_page) - (lin_page << 12);
else
paging.tlb.write[lin_page]=nullptr;
paging.tlb.write[lin_page] = nullptr;

paging.tlb.writehandler[lin_page]=handler;
return;
Expand Down Expand Up @@ -484,7 +494,9 @@ class ExceptionPageHandler : public PageHandler {
X86PageEntry dir_entry;
dir_entry.load = phys_readd(GetPageDirectoryEntryAddr(addr));
if (!dir_entry.dirblock.p) E_Exit("Undesired situation 1 in exception handler.");


if (do_pse && dir_entry.dirblock.ps) E_Exit("PSE and Exception not yet supported");//TODO

// page table entry
tableaddr = GetPageTableEntryAddr(addr, dir_entry);
//Bitu d_index=(addr >> 12) >> 10;
Expand Down Expand Up @@ -801,78 +813,109 @@ class NewInitPageHandler : public PageHandler {
else goto initpage_retry; // TODO maybe E_Exit after a few loops
}

PhysPt tableEntryAddr = GetPageTableEntryAddr(lin_addr, dir_entry);
// Range check to avoid emulator segfault: phys_readd() reads from MemBase+addr and does NOT range check.
if ((tableEntryAddr+4) <= (MEM_TotalPages()<<12u)) {
table_entry.load=phys_readd(tableEntryAddr);
if (do_pse && dir_entry.dirblock.ps) { // 4MB PSE page
Bitu result =
translate_array[((dir_entry.load<<1)&0xc) | ((dir_entry.load>>1)&0x3)];

// save load to see if it changed later
uint32_t dir_load = dir_entry.load;

// if we are writing we can set it right here to save some CPU
if (writing) dir_entry.dirblock4mb.d = 1;

// set page accessed
dir_entry.dirblock4mb.a = 1;

// update if needed
if (dir_load != dir_entry.load)
phys_writed(dirEntryAddr, dir_entry.load);

// if the page isn't dirty and we are reading we need to map the foiler
// (dirty = false)
bool dirty = dir_entry.dirblock4mb.d? true:false;

/* LOG_MSG("INITPSE lin=0x%x phys=0x%lx base22=0x%x base32=0x%x",
(unsigned int)lin_addr,
(unsigned long)(((dir_entry.dirblock4mb.base22<<10ul)|(lin_page&0x3FFul))<<12ul),
(unsigned int)dir_entry.dirblock4mb.base22,
(unsigned int)dir_entry.dirblock4mb.base32); */
// finally install the new page
PAGING_LinkPageNew(lin_page, (dir_entry.dirblock4mb.base22<<10u)|(lin_page&0x3FFu), result, dirty);
}
else {
LOG(LOG_CPU,LOG_WARN)("Page table entry access beyond end of memory, page %08x >= %08x",
(unsigned int)(tableEntryAddr>>12u),(unsigned int)MEM_TotalPages());
table_entry.load=0xFFFFFFFF;
}
PhysPt tableEntryAddr = GetPageTableEntryAddr(lin_addr, dir_entry);
// Range check to avoid emulator segfault: phys_readd() reads from MemBase+addr and does NOT range check.
if ((tableEntryAddr+4) <= (MEM_TotalPages()<<12u)) {
table_entry.load=phys_readd(tableEntryAddr);
}
else {
LOG(LOG_CPU,LOG_WARN)("Page table entry access beyond end of memory, page %08x >= %08x",
(unsigned int)(tableEntryAddr>>12u),(unsigned int)MEM_TotalPages());
table_entry.load=0xFFFFFFFF;
}

// set page table accessed (IA manual: A is set whenever the entry is
// used in a page translation)
if (!dir_entry.dirblock.a) {
dir_entry.dirblock.a = 1;
phys_writed(dirEntryAddr, dir_entry.load);
}
// set page table accessed (IA manual: A is set whenever the entry is
// used in a page translation)
if (!dir_entry.dirblock.a) {
dir_entry.dirblock.a = 1;
phys_writed(dirEntryAddr, dir_entry.load);
}

if (!table_entry.block.p) {
// physpage pointer is not present, do a page fault
PAGING_NewPageFault(lin_addr, tableEntryAddr, prepare_only,
(writing ? 2u : 0u) | (isUser ? 4u : 0u));
if (!table_entry.block.p) {
// physpage pointer is not present, do a page fault
PAGING_NewPageFault(lin_addr, tableEntryAddr, prepare_only,
(writing ? 2u : 0u) | (isUser ? 4u : 0u));

if (prepare_only) return true;
else goto initpage_retry;
}
//PrintPageInfo("INI",lin_addr,writing,prepare_only);
if (prepare_only) return true;
else goto initpage_retry;
}
//PrintPageInfo("INI",lin_addr,writing,prepare_only);

Bitu result =
translate_array[((dir_entry.load<<1)&0xc) | ((table_entry.load>>1)&0x3)];
Bitu result =
translate_array[((dir_entry.load<<1)&0xc) | ((table_entry.load>>1)&0x3)];

// If a page access right exception occurs we shouldn't change a or d
// I'd prefer running into the prepared exception handler but we'd need
// an additional handler that sets the 'a' bit - idea - foiler read?
Bitu ft_index = result | (writing ? 8u : 0u) | (isUser ? 4u : 0u) |
(paging.wp ? 16u : 0u);
// If a page access right exception occurs we shouldn't change a or d
// I'd prefer running into the prepared exception handler but we'd need
// an additional handler that sets the 'a' bit - idea - foiler read?
Bitu ft_index = result | (writing ? 8u : 0u) | (isUser ? 4u : 0u) |
(paging.wp ? 16u : 0u);

if (GCC_UNLIKELY(fault_table[ft_index])) {
// exception error code format:
// bit0 - protection violation, bit1 - writing, bit2 - user mode
PAGING_NewPageFault(lin_addr, tableEntryAddr, prepare_only,
1u | (writing ? 2u : 0u) | (isUser ? 4u : 0u));
if (GCC_UNLIKELY(fault_table[ft_index])) {
// exception error code format:
// bit0 - protection violation, bit1 - writing, bit2 - user mode
PAGING_NewPageFault(lin_addr, tableEntryAddr, prepare_only,
1u | (writing ? 2u : 0u) | (isUser ? 4u : 0u));

if (prepare_only) return true;
else goto initpage_retry; // unlikely to happen?
if (prepare_only) return true;
else goto initpage_retry; // unlikely to happen?
}
// save load to see if it changed later
uint32_t table_load = table_entry.load;

// if we are writing we can set it right here to save some CPU
if (writing) table_entry.block.d = 1;

// set page accessed
table_entry.block.a = 1;

// update if needed
if (table_load != table_entry.load)
phys_writed(tableEntryAddr, table_entry.load);

// if the page isn't dirty and we are reading we need to map the foiler
// (dirty = false)
bool dirty = table_entry.block.d? true:false;
/*
LOG_MSG("INIT %s LIN% 8x PHYS% 5x wr%x ch%x wp%x d%x c%x m%x a%x [%x/%x/%x]",
mtr[result], lin_addr, table_entry.block.base,
writing, prepare_only, paging.wp,
dirty, cpu.cpl, cpu.mpl,
((dir_entry.load<<1)&0xc) | ((table_entry.load>>1)&0x3),
dirEntryAddr, tableEntryAddr, table_entry.load);
*/
// finally install the new page
PAGING_LinkPageNew(lin_page, table_entry.block.base, result, dirty);
}
// save load to see if it changed later
uint32_t table_load = table_entry.load;

// if we are writing we can set it right here to save some CPU
if (writing) table_entry.block.d = 1;

// set page accessed
table_entry.block.a = 1;

// update if needed
if (table_load != table_entry.load)
phys_writed(tableEntryAddr, table_entry.load);

// if the page isn't dirty and we are reading we need to map the foiler
// (dirty = false)
bool dirty = table_entry.block.d? true:false;
/*
LOG_MSG("INIT %s LIN% 8x PHYS% 5x wr%x ch%x wp%x d%x c%x m%x a%x [%x/%x/%x]",
mtr[result], lin_addr, table_entry.block.base,
writing, prepare_only, paging.wp,
dirty, cpu.cpl, cpu.mpl,
((dir_entry.load<<1)&0xc) | ((table_entry.load>>1)&0x3),
dirEntryAddr, tableEntryAddr, table_entry.load);
*/
// finally install the new page
PAGING_LinkPageNew(lin_page, table_entry.block.base, result, dirty);

} else { // paging off
if (lin_page<LINK_START) phys_page=paging.firstmb[lin_page];
Expand Down Expand Up @@ -914,7 +957,9 @@ bool PAGING_MakePhysPage(Bitu & page) {
X86PageEntry dir_entry;
dir_entry.load = phys_readd(GetPageDirectoryEntryAddr((PhysPt)(page<<12)));
if (!dir_entry.dirblock.p) return false;


if (do_pse && dir_entry.dirblock.ps) E_Exit("PSE and MakePhysPage not yet supported");//TODO

// check the page table entry
X86PageEntry tbl_entry;
tbl_entry.load = phys_readd(GetPageTableEntryAddr((PhysPt)(page<<12), dir_entry));
Expand Down

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