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Use recursive paging instead of the smap

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This commit is contained in:
pjht 2020-07-24 08:24:47 -05:00
parent 611e4e1ac2
commit b89ccf600e
1 changed files with 18 additions and 42 deletions
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60
kernel/cpu/i386/paging.c
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@ -12,16 +12,15 @@ static uint32_t page_directory[1024] __attribute__((aligned(4096)));
static uint32_t kern_page_tables[NUM_KERN_FRAMES] __attribute__((aligned(4096)));
static uint32_t kstack_page_tables[218*1024] __attribute__((aligned(4096)));
static uint32_t kmalloc_page_tables[4*1024] __attribute__((aligned(4096)));
static uint32_t smap_page_tables[2048] __attribute__((aligned(4096)));
static uint32_t* smap=(uint32_t*)0xFF800000;
static uint32_t* pagdirmap=(uint32_t*)0xFFFFF000;
static uint32_t* pagtblmap=(uint32_t*)0xFFC00000;
static char is_page_present(size_t page) {
int table=page>>10;
page=page&0x3FF;
if ((smap[table]&0x1)==0) {
if ((pagdirmap[table]&0x1)==0) {
return 0;
}
smap_page_tables[table+1]=(smap[table]&0xFFFFFC00)|0x3;
return smap[(1024+(1024*table))+page]&0x1;
return pagtblmap[page+1024*table]&0x1;
}
void map_pages(void* virt_addr_ptr,void* phys_addr_ptr,int num_pages,char usr,char wr) {
@ -29,18 +28,17 @@ void map_pages(void* virt_addr_ptr,void* phys_addr_ptr,int num_pages,char usr,ch
uint32_t phys_addr=(uint32_t)phys_addr_ptr;
int dir_entry=(virt_addr&0xFFC00000)>>22;
int table_entry=(virt_addr&0x3FF000)>>12;
for (int i=0;i<=num_pages;i++) {
if (!(smap[dir_entry]&0x1)) {
for (int i=0;i<num_pages;i++) {
if (!(pagdirmap[dir_entry]&0x1)) {
int flags=1;
flags=flags|((wr&1)<<1);
flags=flags|((usr&1)<<2);
smap[dir_entry]=(uint32_t)pmem_alloc(1)|flags;
pagdirmap[dir_entry]=(uint32_t)pmem_alloc(1)|flags;
}
smap_page_tables[dir_entry+1]=(smap[dir_entry]&0xFFFFFC00)|0x3;
int flags=1;
flags=flags|((wr&1)<<1);
flags=flags|((usr&1)<<2);
smap[(1024+(1024*dir_entry))+table_entry]=phys_addr|flags;
pagtblmap[table_entry+1024*dir_entry]=phys_addr|flags;
table_entry++;
if (table_entry==1024) {
table_entry=0;
@ -109,11 +107,10 @@ void* virt_to_phys(void* virt_addr_arg) {
if (!is_page_present(virt_addr>>12)) return NULL;
int dir_idx=(virt_addr&0xFFC00000)>>22;
int tbl_idx=(virt_addr&0x3FFC00)>>12;
if ((smap[dir_idx]&0x1)==0) {
if ((pagdirmap[dir_idx]&0x1)==0) {
return 0;
}
smap_page_tables[dir_idx+1]=(smap[dir_idx]&0xFFFFFC00)|0x3;
return (void*)((smap[(1024+(1024*dir_idx))+tbl_idx]&0xFFFFFC00)+offset);
return (void*)((pagtblmap[tbl_idx+1024*dir_idx]&0xFFFFFC00)+offset);
}
@ -127,30 +124,18 @@ void invl_page(void* addr) {
}
void* paging_new_address_space() {
uint32_t cr3=(uint32_t)get_cr3();
void* dir=pmem_alloc(1);
smap_page_tables[0]=((uint32_t)dir)|0x3;
invl_page(smap);
uint32_t* freepg=find_free_pages(1);
map_pages(freepg,dir,1,0,1);
for (size_t i=0;i<1024;i++) {
smap[i]=page_directory[i];
freepg[i]=page_directory[i];
}
smap_page_tables[0]=cr3|0x3;
invl_page(smap);
freepg[1023]=((uint32_t)dir)|0x3;
unmap_pages(freepg,1);
return dir;
}
void load_smap(void* cr3) {
smap_page_tables[0]=(uint32_t)cr3|0x3;
invl_page(&smap[0]);
for (size_t i=1;i<2048;i++) {
invl_page(&smap[i*1024]);
smap_page_tables[i]=0;
}
}
void load_address_space(void* cr3) {
load_smap(cr3);
load_page_directory((uint32_t*)cr3);
}
@ -159,9 +144,8 @@ void unmap_pages(void* start_virt,int num_pages) {
int dir_entry=(virt_addr&0xFFC00000)>>22;
int table_entry=(virt_addr&0x3FF000)>>12;
for (int i=0;i<=num_pages;i++) {
if (smap[dir_entry]&0x1) {
smap_page_tables[dir_entry+1]=(smap[dir_entry]&0xFFFFFC00)|0x3;
smap[(1024+(1024*dir_entry))+table_entry]=0;
if (pagtblmap[dir_entry]&0x1) {
pagtblmap[table_entry+1024*dir_entry]=0;
invl_page(start_virt+(i*1024));
table_entry++;
if (table_entry==1024) {
@ -182,10 +166,6 @@ void paging_init() {
for (size_t i=0;i<4*1024;i++) {
kmalloc_page_tables[i]=(uint32_t)pmem_alloc(1)|0x3;
}
smap_page_tables[0]=(((uint32_t)&(page_directory))-0xC0000000)|0x3;
for (size_t i=1;i<2048;i++) {
smap_page_tables[i]=0;
}
for (size_t i=0;i<NUM_KERN_FRAMES/1024;i++) {
uint32_t entry_virt=(uint32_t)&(kern_page_tables[i*1024]);
page_directory[i+768]=(entry_virt-0xC0000000)|0x3;
@ -195,11 +175,7 @@ void paging_init() {
uint32_t entry_virt=(uint32_t)&(kmalloc_page_tables[i*1024]);
page_directory[i+1018]=(entry_virt-0xC0000000)|0x3;
}
// page_directory[1018,1021]=(((uint32_t)kmalloc_page_tables)-0xC0000000)|0x3;
for (size_t i=0;i<2;i++) {
uint32_t entry_virt=(uint32_t)&(smap_page_tables[i*1024]);
page_directory[i+1022]=(entry_virt-0xC0000000)|0x3;
}
page_directory[1023]=((uint32_t)page_directory-0xC0000000)|0x3;
load_page_directory((uint32_t*)((uint32_t)page_directory-0xC0000000));
}