aboutsummaryrefslogtreecommitdiff
path: root/src/core/paging.c
diff options
context:
space:
mode:
Diffstat (limited to 'src/core/paging.c')
-rw-r--r--src/core/paging.c26
1 files changed, 10 insertions, 16 deletions
diff --git a/src/core/paging.c b/src/core/paging.c
index 0ab5498..cf5b951 100644
--- a/src/core/paging.c
+++ b/src/core/paging.c
@@ -89,42 +89,36 @@ char* paging_allocate_next_page(){
asm("hlt");
}
-// TODO: Take p into account
int *paging_allocate(int p){
- // ----- Allow kernel access during interruption
+ // ----- Populate kernel adresses (to be able to execute interrupts codes)
int *page_dir=(int*)paging_allocate_next_page();
int *k_page_table=(int*)paging_allocate_next_page();
- // Init page directory
+ // Kernel is located in the first 4Mb (page dir entry 0)
page_dir[0]=(int)k_page_table|3;
- // Init page table 0
int addr_offset=0;
for(int i=0;i<1024;i++){
k_page_table[i]=addr_offset;
- k_page_table[i]|=3; // Permission
+ k_page_table[i]|=3; // Permissions
addr_offset+=PAGING_PAGE_SIZE; // 4Ko pages
}
- // ----- Task table
- int *u_page_table=(int*)paging_allocate_next_page();
+ // ----- Populate task adresses
+ int *u_page_table=(int)paging_allocate_next_page();
page_dir[1]=(int)u_page_table|7;
- u_page_table[0]=(int)page_dir|7; // Virtual address is 1024*4096/4
- u_page_table[1]=(int)k_page_table|7;
- u_page_table[2]=(int)u_page_table|7;
-
- int dir_entry=1;
- int pt_entry=3;
+ int dir_entry=1; // Entry point is at 1024*4096=4194304 (page dir entry 1 and page table entry 0)
+ int pt_entry=0;
int p_current=max(1,p); // Allocate at least 1 page
while(p_current!=0){
+ u_page_table[pt_entry]=(int)paging_allocate_next_page()|7;
+ p_current--;
+ pt_entry++;
if(pt_entry%1024==0){
dir_entry++;
pt_entry=0;
u_page_table=(int*)paging_allocate_next_page();
page_dir[dir_entry]=(int)u_page_table|7;
}
- u_page_table[pt_entry]=(int)paging_allocate_next_page()|7;
- p_current--;
}
-
return page_dir;
}