feat: setup bitmap for physical allocator

.gitignore

@@ -3,6 +3,7 @@
 *.bin
 *.iso
 *~
+\#*\#
 
 *.elf
 *.a
@@ -11,3 +12,5 @@ vmstupid
 
 
 /sysroot
+
+log.txt

README.md

@@ -5,7 +5,7 @@
 [Website](https://stupidos.d0p1.eu)
 ![GitHub](https://img.shields.io/github/license/d0p1s4m4/stupidos?logoColor=white&style=flat-square)
 ![GitHub issues](https://img.shields.io/github/issues/d0p1s4m4/stupidos?style=flat-square)
-[![GitHub Sponsors](https://img.shields.io/github/sponsors/d0p1s4m4)](https://github.com/sponsors/d0p1s4m4?style=flat-square)
+[![GitHub Sponsors](https://img.shields.io/github/sponsors/d0p1s4m4?style=flat-square)](https://github.com/sponsors/d0p1s4m4)
 
 </div>
 

kernel/head.s

@@ -68,6 +68,7 @@ entry:
 	jmp hang
 
 .mem_ok:
+	LOG msg_pmm_initialized
 
 	extern setup_paging
 	call setup_paging
@@ -81,6 +82,7 @@ section .rodata
 
 msg_hello_world db "StupidOS v", STUPID_VERSION, " (built with ", NASM_VERSION, " on ", BUILD_DATE, ")", 0
 msg_boot_info db "Bootloader: %s", 0
+msg_pmm_initialized db "PMM initialized", 0
 err_invalid_boot_magic db "[ERROR] Invalid boot magic (got: %x, expected: 0x2BADB002)", 0
 err_cannot_map_memory db "[ERROR] Can't map memory", 0
 

kernel/idt.s

@@ -4,6 +4,7 @@ global setup_idt
 setup_idt:
 %assign i 0
 %rep 32
+	;; TODO: refactor
 extern isr %+ i
 	mov eax, isr %+ i
 	; offset (low)

kernel/linker.ld

@@ -26,3 +26,5 @@ SECTIONS
 
 	kernel_end = .;
 }
+
+kernel_size = kernel_end - kernel_start;

kernel/pmm.s

@@ -1,9 +1,280 @@
 [BITS 32]
+	;; XXX: align address to page
 
 %include "base.inc"
 %include "multiboot.inc"
 
+extern kernel_size
+extern kernel_end
+	
+struc bitmap
+	.length: resd 1
+	.addr: resd 1
+endstruc
+
 section .text
+
+bitmap_count_free_page:
+	push ebp
+	mov ebp, esp
+	push edi
+	push esi
+	push ebx
+
+	mov edi, [bitmap_info + bitmap.addr]
+	xor ebx, ebx
+
+.loop:
+
+	inc edi
+	inc ebx
+	cmp ebx, [bitmap_info]
+	jb .loop
+.end:	
+	pop ebx
+	pop esi
+	pop edi
+	leave
+	ret
+
+bitmap_mark:
+	push ebp
+	mov ebp, esp
+	push edi
+	push esi
+
+	mov edi, 1
+	mov eax, [ebp + 8]
+	and eax, 0x7				; eax % 8
+	mov ecx, eax
+	shl edi, cl
+
+	mov eax, [ebp + 8]
+	shr eax, 0x3				; eax / 8
+	mov esi, [bitmap_info + bitmap.addr]
+	add esi, eax
+	mov dl, byte [esi]
+
+	mov ecx, [ebp + 12]
+	test ecx, ecx
+	jz .clear
+
+	or edx, edi					; set bit
+	jmp .end
+
+.clear:
+	not edi
+	and edx, edi				; clear bit
+
+.end:
+	mov byte [esi], dl
+
+	pop esi
+	pop edi
+	leave
+	ret
+	
+init_bitmap:
+	push ebp
+	mov ebp, esp
+	push edi
+
+	mov ecx, [bitmap_info]
+	mov al, 0xFF
+	mov edi, [bitmap_info + bitmap.addr]
+	rep stosb
+
+	pop edi
+	leave
+	ret
+
+bitmap_mark_range_free:
+	push ebp
+	mov ebp, esp
+	push edi
+	push esi
+	push ebx
+
+	mov edi, [ebp + 8]			; start address
+	mov esi, [ebp + 12]			; length
+	xor ebx, ebx				; counter (I know I SHOUD use 'ecx' as counter
+								; but since the ABI state it's not preserved
+								; accross function call) 
+	push dword 0				; bitmap_mark(addr, 0) == clear
+.loop:
+	cmp ebx, esi
+	jnb .end_loop
+	add edi, ebx
+	jc .end_loop				; exit on overflow
+	push edi
+	call bitmap_mark
+	add esp, 4
+
+	add ebx, 0x1000				; add page size
+	jmp .loop
+.end_loop:
+	add esp, 4
+	pop ebx
+	pop esi
+	pop edi
+	leave
+	ret
+	
+setup_pmm_mmap:
+	push ebp
+	mov ebp, esp
+	sub esp, 4
+	push edi
+	push esi
+	push ebx
+
+	mov edi, [ebp + 8]			; mb_mmap struct addr
+	mov esi, [ebp + 12]			; mmap length
+	xor ebx, ebx				; pass
+	mov [ebp - 4], ebx			; set max addr to 0
+.loop:
+	;; TODO: PAE stuff
+	;; skip address > 32bit
+	mov eax, [edi + mb_mmap.addr + 4]
+	and eax, eax
+	jnz .next
+	mov eax, [edi + mb_mmap.length + 4]
+	and eax, eax
+	jnz .next
+
+	;; check if first pass
+	and ebx, ebx
+	jz .first_pass
+	mov eax, [edi + mb_mmap.type]
+	and eax, 0x1 				; check if free
+	jz .next
+	;;
+	mov eax, [bitmap_info]
+	mov ecx, [mb_mmap.length]
+	cmp eax, ecx
+	ja .next
+
+	cmp ebx, 0x1
+	jne .third_pass
+	mov eax, [edi + mb_mmap.addr]
+	mov [bitmap_info + bitmap.addr], eax
+	LOG msg_bitmap_stored_at, eax
+	call init_bitmap			; mark all memory as used
+	jmp .bitmap_size_already_set
+	
+	;; TODO: mark as free in bitmap
+.third_pass:
+	push dword [edi + mb_mmap.addr]
+	push dword [edi + mb_mmap.length]
+	call bitmap_mark_range_free
+	add esp, 8
+	jmp .next
+
+	;; first pass then calculate higher address
+.first_pass:
+	LOG msg_mmap_entry, dword [edi + mb_mmap.addr + 4], \
+		dword [edi + mb_mmap.addr], \
+		dword [edi + mb_mmap.length + 4], \
+		dword [edi + mb_mmap.length], \
+		dword [edi + mb_mmap.type]  
+	mov eax, [edi + mb_mmap.length]
+	add eax, [edi + mb_mmap.addr]
+	jnc .no_overflow
+	mov eax, -1					; if overflow set eax to (uint32_t)-1
+.no_overflow:
+	mov edx, [ebp - 4]
+	cmp edx, eax
+	ja .next
+	mov [ebp - 4], eax
+	
+.next:
+	mov eax, [edi + mb_mmap.size]
+	add eax, 0x4
+	add edi, eax				; jump to next entry
+	sub esi, eax
+	jnz .loop
+
+	and ebx, ebx
+	jnz .bitmap_size_already_set
+	LOG msg_max_mem, dword [ebp - 4]
+
+	mov eax, [ebp - 4]
+	shr eax, 15					; eax / (4096*8)
+	mov [bitmap_info], eax
+
+.bitmap_size_already_set:
+	
+	inc ebx
+	cmp ebx, 2
+	jbe .loop
+	
+	pop ebx
+	pop esi
+	pop edi
+	leave
+	ret
+
+setup_pmm_legacy:
+	push ebp
+	mov ebp, esp
+	push edi
+	push esi
+	push ebx
+	xor eax, eax
+	mov ecx, [ebp + 8]
+	shl ecx, 0xA				; ecx * 1KiB
+	mov esi, ecx
+	LOG msg_mem_block, eax, ecx
+	
+	mov eax, 0x100000 
+	mov ecx, [ebp + 12]
+	shl ecx, 0xA				; ecx * 1KiB
+	mov ebx, ecx
+	mov edi, eax
+	add edi, ecx
+	LOG msg_mem_block, eax, ecx
+
+	LOG msg_max_mem, edi
+
+	shr edi, 15					; (edi / (4046*8))
+	mov dword [bitmap_info], edi
+
+	cmp edi, esi
+	ja .try_high
+	mov dword [bitmap_info + bitmap.addr], 0
+	jmp .initialize_bitmap
+
+.try_high:
+	mov eax, ebx
+	sub ebx, kernel_size
+	cmp edi, ebx
+	ja .err_no_mem
+	mov dword [bitmap_info + bitmap.addr], kernel_end
+
+.initialize_bitmap:
+	call init_bitmap
+
+	push esi
+	push dword 0
+	call bitmap_mark_range_free
+
+	push ebx
+	push dword 0x100000
+	call bitmap_mark_range_free
+
+	xor eax, eax
+	jmp .end
+	
+.err_no_mem:
+	mov eax, 1
+
+.end:
+	pop ebx
+	pop esi
+	pop edi
+	leave
+	ret
+
 global setup_pmm
 setup_pmm:
 	push ebp
@@ -15,22 +286,13 @@ setup_pmm:
 	mov edi, [ebp + 8]
 
 	mov eax, [edi]
-	and eax, 0x40 ; (1 << 6)
+	and eax, 0x40				; (1 << 6)
 	jz .no_mmap
-	mov esi, [edi + mb_info.mmap_length]
+
-	mov ebx, [edi + mb_info.mmap_addr]
+	push dword [edi + mb_info.mmap_length]
-.loop:
+	push dword [edi + mb_info.mmap_addr]
-	mov eax, ebx
+	call setup_pmm_mmap
-	LOG msg_mmap_entry, dword [eax + mb_mmap.addr + 4], \
+	add esp, 8
-						dword [eax + mb_mmap.addr], \
-						dword [eax + mb_mmap.length + 4], \
-						dword [eax + mb_mmap.length], \
-						dword [eax + mb_mmap.type]
-	mov eax, [ebx + mb_mmap.size]
-	add eax, 0x4
-	add ebx, eax
-	sub esi, eax
-	jnz .loop
 
 	jmp .end_mem_detection
 
@@ -40,16 +302,30 @@ setup_pmm:
 	and eax, 0x1
 	jz .err
 
-	xor eax, eax
+	push dword [edi + mb_info.mem_upper]
-	mov ecx, [edi + mb_info.mem_lower]
+	push dword [edi + mb_info.mem_lower]
-	shl ecx, 0xA ; ecx * 1KiB
+	call setup_pmm_legacy
-	LOG msg_mem_block, eax, ecx
+	add esp, 8
-	mov eax, 0x100000
-	mov ecx, [edi + mb_info.mem_upper]
-	shl ecx, 0xA
-	LOG msg_mem_block, eax, ecx
 
 .end_mem_detection:
+	;; mark bitmap as used
+	xor ebx, ebx
+	mov edi, [bitmap_info + bitmap.addr]
+	mov esi, [bitmap_info]
+	push dword 1				; bitmap_mark(addr, 1) == set
+
+.loop:
+	cmp ebx, edi
+	jnb .end_loop
+	add edi, ebx
+	push edi
+	call bitmap_mark
+	add esp, 4
+
+	add ebx, 0x1000
+	jmp .loop
+.end_loop:
+	add esp, 4					; previous "push dword 0"
 
 	xor eax, eax
 	jmp .end
@@ -62,6 +338,27 @@ setup_pmm:
 	leave
 	ret
 
+global alloc_frame
+alloc_frame:
+	push esp
+	mov ebp, esp
+	
+	leave
+	ret
+
+global free_frame
+free_frame:
+	push esp
+	mov ebp, esp
+
+	leave
+	ret
+	
+section .data
+bitmap_info:
+	dd 0 ; size
+	dd 0 ; ptr
+
 section .rodata
 warn_no_mmap db "[WARN] mmap flag not set", 0
 msg_mmap_entry db "Memory Map Entry:", 0xA
@@ -71,4 +368,6 @@ msg_mmap_entry db "Memory Map Entry:", 0xA
 msg_mem_block db "Free Memory:", 0xA
 	db 0x9, "Address: %x", 0xA
 	db 0x9, "Length: %x", 0
+msg_max_mem db "Max memory: %x", 0
+msg_bitmap_stored_at db "Bitmap stored at: %x", 0
 file db __FILE__, 0

kernel/syscall.s

@@ -0,0 +1,11 @@
+[BITS 32]
+
+global syscall_table
+syscall_table:
+	dd 0						; sys_exit
+	dd 0						; sys_fork
+	dd 0						; sys_read
+	dd 0						; sys_write
+	dd 0						; sys_open
+	dd 0						; sys_close
+.end: