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Added function to map single page to specific frame

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This commit is contained in:
Nathan Giddings
2020-12-09 06:24:27 -06:00
parent 2bff533ec1
commit b3b4154979
2 changed files with 33 additions and 24 deletions
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2
src/mmap.hpp
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@@ -14,6 +14,8 @@ int mmap(void* start, size_t length, int flags);
int mmap(void* start, physaddr_t p_start, size_t length, int flags);
int mapPage(void* start, physaddr_t p_start, int flags);
int munmap(void* start, size_t length);
bool isMapped(void* addr);

55
src/x86/mmap.cpp
View File

@@ -178,7 +178,6 @@ int kernel::mmap(void* start, size_t length, int flags)
pageTables[tableIndex].setUsermode(false);
if(flags & MMAP_RW)
pageTables[tableIndex].setRw(true);
}
tableIndex++;
}
@@ -186,6 +185,20 @@ int kernel::mmap(void* start, size_t length, int flags)
}
int kernel::mmap(void* start, physaddr_t p_start, size_t length, int flags)
{
if((size_t) start % 4096 != 0 || p_start % 4096 != 0)
return -1;
physaddr_t page = p_start;
for(int i = (int) length; i > 0; i -= 4096)
{
if(mapPage(start, page, flags) != 0)
return -1;
page += 4096;
}
return 0;
}
int kernel::mapPage(void* start, physaddr_t p_start, int flags)
{
if((size_t) start % 4096 != 0 || p_start % 4096 != 0)
return -1;
@@ -193,30 +206,24 @@ int kernel::mmap(void* start, physaddr_t p_start, size_t length, int flags)
PageTableEntry* pageDirectory = (PageTableEntry*) 0xFFFFF000;
size_t tableIndex = (size_t) start / 4096;
physaddr_t page = p_start;
for(int i = (int) length; i > 0; i -= 4096)
size_t directoryIndex = tableIndex / 1024;
if(!pageDirectory[directoryIndex].getPresent())
{
size_t directoryIndex = tableIndex / 1024;
if(!pageDirectory[directoryIndex].getPresent())
{
physaddr_t newPT = State::pageAllocator.allocate(4096);
if(newPT == 0)
return -1;
pageDirectory[directoryIndex] = newPT;
pageDirectory[directoryIndex].setPresent(true);
pageDirectory[directoryIndex].setUsermode(false);
pageDirectory[directoryIndex].setRw(true);
}
if(!pageTables[tableIndex].getPresent())
{
pageTables[tableIndex] = page;
pageTables[tableIndex].setPresent(true);
pageTables[tableIndex].setUsermode(false);
if(flags & MMAP_RW)
pageTables[tableIndex].setRw(true);
}
tableIndex++;
page += 4096;
physaddr_t newPT = State::pageAllocator.allocate(4096);
if(newPT == 0)
return -1;
pageDirectory[directoryIndex] = newPT;
pageDirectory[directoryIndex].setPresent(true);
pageDirectory[directoryIndex].setUsermode(false);
pageDirectory[directoryIndex].setRw(true);
}
if(!pageTables[tableIndex].getPresent())
{
pageTables[tableIndex] = page;
pageTables[tableIndex].setPresent(true);
pageTables[tableIndex].setUsermode(false);
if(flags & MMAP_RW)
pageTables[tableIndex].setRw(true);
}
return 0;
}