diff options
Diffstat (limited to 'kernel/src/boot.asm')
| -rw-r--r-- | kernel/src/boot.asm | 33 |
1 files changed, 23 insertions, 10 deletions
diff --git a/kernel/src/boot.asm b/kernel/src/boot.asm index 95b699a..1c0b3da 100644 --- a/kernel/src/boot.asm +++ b/kernel/src/boot.asm @@ -5,14 +5,16 @@ section .text bits 32 start: mov esp, stack_top - + call check_multiboot call check_cpuid call check_long_mode call setup_page_tables call enable_paging - ; load the 64-bit GDT + + + ; load the 64-bit GDT lgdt [gdt64.pointer] jmp gdt64.code:long_mode_start @@ -96,21 +98,27 @@ setup_page_tables: .map_p2_table: ; map ecx-th P2 entry to a huge page that starts at address 2MiB*ecx + mov ebx, eax + cmp eax, stack_bottom + 0b10000011 - 0x400000 + jne .hit_stack + and ebx, ~1 mov [p2_table + ecx ], eax ; map ecx-th entry - add eax, 0x200000 ; 2MiB - mov [p2_table + ecx + 8 ], eax ; map ecx-th entry - add eax, 0x200000 ; 2MiB - mov [p2_table + ecx + 16], eax ; map ecx-th entry - add eax, 0x200000 ; 2MiB - mov [p2_table + ecx + 24], eax ; map ecx-th entry + add ecx, 8 + +.hit_stack: + mov [p2_table + ecx ], ebx ; map ecx-th entry add eax, 0x200000 ; 2MiB - add ecx, 32 + add ecx, 8 + ;add ecx, 32 cmp ecx, 4096 ; if counter == 512, the whole P2 table is mapped jne .map_p2_table ; else map the next entry ret + + + enable_paging: mov eax, p4_table mov cr3, eax @@ -131,6 +139,10 @@ enable_paging: or eax, 1 << 31 mov cr0, eax + ; move stack pointer to accommodate for the guard page + add esp, 0x200000 + + ret section .rodata @@ -159,6 +171,7 @@ p3_table: resb 4096 p2_table: resb 4096 +alignb 4096 * 512 stack_bottom: - resb 4096 * 8 + resb 4096 * 4 stack_top: |