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Updated virtual memory manager

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Added page flags
Added function current_address_space()
Fixed create_address_space()
Renamed some fields in page_table_entry_t to fit naming scheme
This commit is contained in:
ngiddings
2021-04-17 00:52:16 -05:00
parent 6c047c6343
commit fdcdb9acab
2 changed files with 37 additions and 23 deletions
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40
src/x86/mmgr.c
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@@ -11,28 +11,17 @@ const size_t page_bits = 12;
struct page_table_entry_t
{
uint32_t present : 1;
uint32_t rw : 1;
uint32_t usermode : 1;
uint32_t writeThrough : 1;
uint32_t cacheDisable : 1;
uint32_t write_through : 1;
uint32_t cache_disable : 1;
uint32_t accessed : 1;
uint32_t dirty : 1;
uint32_t pat : 1;
uint32_t global : 1;
uint32_t shared : 1;
uint32_t ignored : 2;
uint32_t physicalAddress : 20;
uint32_t physical_address : 20;
};
struct page_table_entry_t *page_tables = (struct page_table_entry_t *)0xFFC00000;
@@ -47,12 +36,14 @@ physaddr_t create_address_space(struct page_stack_t *page_stack)
return S_OUT_OF_MEMORY;
}
struct page_table_entry_t buffer = page_directory[0];
page_directory[0].physicalAddress = table >> page_bits;
page_directory[0].physical_address = table >> page_bits;
asm volatile("invlpg 0xFFC00000" ::
: "memory");
memset((void *)page_tables, 0, 1022 * 4);
page_tables[1022] = page_directory[1022];
page_tables[1023] = page_directory[1023];
page_tables[1023].physical_address = table >> page_bits;
page_tables[1023].present = 1;
page_tables[1023].rw = 1;
page_directory[0] = buffer;
asm volatile("invlpg 0xFFC00000" ::
: "memory");
@@ -67,6 +58,11 @@ void load_address_space(physaddr_t table)
: "memory");
}
physaddr_t current_address_space()
{
return page_directory[1023].physical_address << 12;
}
int map_page(struct page_stack_t *page_stack, void *page, physaddr_t frame, int flags)
{
if ((size_t)page % page_size != 0 || frame % page_size != 0)
@@ -82,15 +78,15 @@ int map_page(struct page_stack_t *page_stack, void *page, physaddr_t frame, int
{
return S_OUT_OF_MEMORY;
}
page_directory[directory_index].physicalAddress = new_table >> page_bits;
page_directory[directory_index].physical_address = new_table >> page_bits;
page_directory[directory_index].present = 1;
page_directory[directory_index].usermode = 0;
page_directory[directory_index].usermode = (directory_index < 1022) ? 1 : 0;
page_directory[directory_index].rw = 1;
}
page_tables[table_index].physicalAddress = frame >> 12;
page_tables[table_index].physical_address = frame >> 12;
page_tables[table_index].present = 1;
page_tables[table_index].usermode = 1;
page_tables[table_index].rw = 1;
page_tables[table_index].usermode = (flags & PAGE_USERMODE) ? 1 : 0;
page_tables[table_index].rw = (flags & PAGE_RW) ? 1 : 0;
asm volatile("invlpg (%0)"
:
: "r"(page)
@@ -112,7 +108,7 @@ physaddr_t unmap_page(void *page)
}
else
{
physaddr_t frame = page_tables[table_index].physicalAddress << page_bits;
physaddr_t frame = page_tables[table_index].physical_address << page_bits;
memset(&page_tables[table_index], 0, sizeof(struct page_table_entry_t));
asm volatile("invlpg (%0)"
: