if ~defined mem_inc
mem_inc_fix:
mem_inc fix mem_inc_fix
;include "memmanag.inc"
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;High-level memory management in MenuetOS.
;;It uses memory manager in memmanager.inc
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
second_base_address=0xC0000000
std_application_base_address=0x10000000
general_page_table_ dd 0
general_page_table=general_page_table_+second_base_address
;-----------------------------------------------------------------------------
create_general_page_table:
;input
; none
;output
; none
;Procedure create general page directory and write
;it address to [general_page_table].
pushad
mov eax,1 ;alloc 1 page
mov ebx,general_page_table ;write address to [general_page_table]
call MEM_Alloc_Pages ;allocate page directory
mov eax,[general_page_table]
call MEM_Get_Linear_Address ;eax - linear address of page directory
mov edi,eax
mov ebx,eax ;copy address of page directory to safe place
xor eax,eax
mov ecx,4096/4
cld
rep stosd ;clear page directory
mov eax,4
mov edx,eax
call MEM_Alloc_Pages ;alloc page tables for 0x0-0x1000000 region
cmp eax,edx
jnz $ ;hang if not enough memory
;fill page tables
xor esi,esi
mov ebp,7
.loop:
;esi - number of page in page directory
;ebp - current page address
;ebx - linear address of page directory
mov eax,[ebx+4*esi]
add dword [ebx+4*esi],7 ;add flags to address of page table
call MEM_Get_Linear_Address
;eax - linear address of page table
mov ecx,4096/4
;ecx (counter) - number of pages in page table
;current address=4Mb*esi
.loop1:
mov [eax],ebp ;write page address (with flags) in page table
add eax,4
add ebp,4096 ;size of page=4096 bytes
loop .loop1
inc esi ;next page directory entry
cmp esi,edx
jnz .loop
;map region 0x80000000-0x807fffff to LFB
mov eax,2 ;size of the region is 4Mb so only 1 page table needed
mov edx,ebx ;ebx still contains linear address of the page directory
add ebx,0x800
call MEM_Alloc_Pages ;alloc page table for the region
mov eax,[ebx]
add dword [ebx],7 ;add flags
call MEM_Get_Linear_Address ;get linear address of the page table
mov ecx,4096/4 ;number of pages in page table
mov edi,[0xfe80]
add edi,7
.loop3:
;eax - linear address of page table
;edi - current linear address with flags
mov [eax],edi
add eax,4
add edi,4096
loop .loop3
mov eax,[ebx+4]
call MEM_Get_Linear_Address
add dword [ebx+4],7
mov ecx,4096/4
.loop31:
mov [eax],edi
add eax,4
add edi,4096
loop .loop31
;map region 0xC0000000-* to 0x0-*
mov esi,edx ;esi=linear address of the page directory
lea edi,[esi+(second_base_address shr 20)];add offset of entry (0xC00)
mov ecx,4
rep movsd ;first 16Mb of the region mapped as 0x0-0x1000000 block
mov eax,[0xfe8c] ;eax=memory size
add eax,0x3fffff
shr eax,22
mov esi,eax ;calculate number of entries in page directory
sub esi,4 ;subtract entries for first 16Mb.
mov ebp,0x1000000+7 ;start physical address with flags
;mapping memory higher than 16Mb
.loop4:
;esi (counter) - number of entries in page directory
;edi - address of entry
test esi,esi
jle .loop4end
call MEM_Alloc_Page ;alloc page table for entry in page directory
mov [edi],eax
add dword [edi],7 ;write physical address of page table in page directory
add edi,4 ;move entry pointer
call MEM_Get_Linear_Address
mov ecx,eax
xor edx,edx
.loop5:
;ecx - linear address of page table
;edx - index of page in page table
;ebp - current mapped physical address with flags
mov [ecx+4*edx],ebp ;write address of page in page table
add ebp,0x1000 ;move to next page
inc edx
cmp edx,4096/4
jl .loop5
dec esi
jmp .loop4
.loop4end:
.set_cr3:
;set value of cr3 register to the address of page directory
mov eax,[general_page_table]
add eax,8+16 ;add flags
mov cr3,eax ;now we have full access paging
popad
ret
;-----------------------------------------------------------------------------
simple_clone_cr3_table:
;Parameters:
; eax - physical address of cr3 table (page directory)
;result:
; eax - physical address of clone of cr3 table.
;Function copy only page directory.
push ecx
push edx
push esi
push edi
call MEM_Get_Linear_Address
;eax - linear address of cr3 table
mov esi,eax
call MEM_Alloc_Page
test eax,eax
jz .failed
;eax - physical address of new page diretory
mov edx,eax
call MEM_Get_Linear_Address
mov edi,eax
mov ecx,4096/4
cld
;esi - address of old page directory
;edi - address of new page directory
rep movsd ;copy page directory
mov eax,edx
.failed:
pop edi
pop esi
pop edx
pop ecx
ret
;-----------------------------------------------------------------------------
create_app_cr3_table:
;Parameters:
; eax - slot of process (index in 0x3000 table)
;result:
; eax - physical address of table.
;This function create page directory for new process and
;write it physical address to offset 0xB8 of extended
;process information.
push ebx
mov ebx,eax
mov eax,[general_page_table]
call simple_clone_cr3_table ;clone general page table
shl ebx,8
mov [second_base_address+0x80000+ebx+APPDATA.dir_table],eax ;save address of page directory
pop ebx
ret
;-----------------------------------------------------------------------------
get_cr3_table:
;Input:
; eax - slot of process
;result:
; eax - physical address of page directory
shl eax,8 ;size of process extended information=256 bytes
mov eax,[second_base_address+0x80000+eax+APPDATA.dir_table]
ret
;-----------------------------------------------------------------------------
dispose_app_cr3_table:
;Input:
; eax - slot of process
;result:
; none
;This procedure frees page directory,
;page tables and all memory of process.
pushad
mov ebp,eax
;ebp = process slot in the procedure.
shl eax,8
mov eax,[second_base_address+0x80000+eax+APPDATA.dir_table]
mov ebx,eax
;ebx = physical address of page directory
call MEM_Get_Linear_Address
mov edi,eax
;edi = linear address of page directory
mov eax,[edi+(std_application_base_address shr 20)]
and eax,not (4096-1)
call MEM_Get_Linear_Address
mov esi,eax
;esi = linear address of first page table
;search threads
; mov ecx,0x200
xor edx,edx
mov eax,0x2
.loop:
;eax = current slot of process
mov ecx,eax
shl ecx,5
cmp byte [second_base_address+0x3000+ecx+TASKDATA.state],9 ;if process running?
jz .next ;skip empty slots
shl ecx,3
cmp [second_base_address+0x80000+ecx+APPDATA.dir_table],ebx ;compare page directory addresses
jnz .next
inc edx ;thread found
.next:
inc eax
cmp eax,[0x3004] ;exit loop if we look through all processes
jle .loop
;edx = number of threads
;our process is zombi so it isn't counted
cmp edx,1
jg .threadsexists
;if there isn't threads then clear memory.
add edi,std_application_base_address shr 20
.loop1:
;edi = linear address of current directory entry
;esi = linear address of current page table
test esi,esi
jz .loop1end
xor ecx,ecx
.loop2:
;ecx = index of page
mov eax,[esi+4*ecx]
test eax,eax
jz .loopend ;skip empty entries
and eax,not (4096-1) ;clear flags
push ecx
call MEM_Free_Page ;free page
pop ecx
.loopend:
inc ecx
cmp ecx,1024 ;there are 1024 pages in page table
jl .loop2
mov eax,esi
call MEM_Free_Page_Linear ;free page table
.loop1end:
add edi,4 ;move to next directory entry
mov eax,[edi]
and eax,not (4096-1)
call MEM_Get_Linear_Address
mov esi,eax ;calculate linear address of new page table
test edi,0x800
jz .loop1 ;test if we at 0x80000000 address?
and edi,not (4096-1) ;clear offset of page directory entry
mov eax,edi
call MEM_Free_Page_Linear ;free page directory
popad
ret
.threadsexists: ;do nothing
popad ;last thread will free memory
ret
;-----------------------------------------------------------------------------
mem_alloc_specified_region:
;eax - linear directory address
;ebx - start address (aligned to 4096 bytes)
;ecx - size in pages
;result:
; eax=1 - ok
; eax=0 - failed
;Try to alloc and map ecx pages to [ebx;ebx+4096*ecx) interval.
pushad
mov ebp,ebx ;save start address for recoil
mov esi,eax
.gen_loop:
;esi = linear directory address
;ebx = current address
;ecx = remaining size in pages
mov edx,ebx
shr edx,22
mov edi,[esi+4*edx] ;find directory entry for current address
test edi,edi
jnz .table_exists ;check if page table allocated
call MEM_Alloc_Page ;alloc page table
test eax,eax
jz .failed
mov [esi+4*edx],eax
add dword [esi+4*edx],7 ;write it address with flags
call MEM_Get_Linear_Address
call mem_fill_page ;clear page table
jmp .table_linear
.table_exists:
;calculate linear address of page table
mov eax,edi
and eax,not (4096-1) ;clear flags
call MEM_Get_Linear_Address
.table_linear:
;eax = linear address of page table
mov edx,ebx
shr edx,12
and edx,(1024-1) ;calculate index in page table
mov edi,eax
.loop:
;edi = linear address of page table
;edx = current page table index
;ecx = remaining size in pages
;ebx = current address
test ecx,ecx
jle .endloop1 ;all requested pages allocated
call MEM_Alloc_Page ;alloc new page
test eax,eax
jz .failed
mov [edi+4*edx],eax
add dword [edi+4*edx],7 ;write it address with flags
call MEM_Get_Linear_Address
call mem_fill_page ;clear new page
;go to next page table entry
dec ecx
add ebx,4096
inc edx
test edx,(1024-1)
jnz .loop
jmp .gen_loop
.endloop1:
popad
mov eax,1 ;ok
ret
.failed:
;calculate data for recoil
sub ebx,ebp
shr ebx,12
mov ecx,ebx ;calculate number of allocated pages
mov eax,esi ;restore linear address of page directory
mov ebx,ebp ;restore initial address
call mem_free_specified_region ;free all allocated pages
popad
xor eax,eax ;fail
ret
;-----------------------------------------------------------------------------
mem_fill_page:
;Input:
; eax - address
;result:
; none
;set to zero 4096 bytes at eax address.
push ecx
push edi
mov edi,eax
mov ecx,4096/4
xor eax,eax
rep stosd
lea eax,[edi-4096]
pop edi
pop ecx
ret
;-----------------------------------------------------------------------------
mem_free_specified_region:
;eax - linear page directory address
;ebx - start address (aligned to 4096 bytes)
;ecx - size in pages
;result - none
;Free pages in [ebx;ebx+4096*ecx) region.
pushad
mov esi,eax
xor ebp,ebp
.gen_loop:
;esi = linear page directory address
;ebx = current address
;ecx = remaining pages
;ebp = 0 for first page table
; 1 otherwise
mov edx,ebx
shr edx,22
mov eax,[esi+4*edx] ;find directory entry for current address
and eax,not (4096-1)
test eax,eax
jnz .table_exists
;skip absent page tables
mov edx,ebx
shr edx,12
and edx,(1024-1) ;edx - index of current page
add ebx,1 shl 22
add ecx,edx
and ebx,not ((1 shl 22)-1)
mov ebp,1 ;set flag
sub ecx,1024 ;ecx=ecx-(1024-edx)
jg .gen_loop
popad
ret
.table_exists:
call MEM_Get_Linear_Address
;eax - linear address of table
mov edx,ebx
shr edx,12
and edx,(1024-1) ;edx - index of current page
mov edi,eax
.loop:
;edi = linear address of page table entry
;edx = index of page table entry
;ecx = remaining pages
test ecx,ecx
jle .endloop1
mov eax,[edi+4*edx]
and eax,not (4096-1)
call MEM_Free_Page ;free page
mov dword [edi+4*edx],0 ;and clear page table entry
dec ecx
inc edx
cmp edx,1024
jl .loop
test ebp,ebp
jz .first_page
mov eax,edi
call MEM_Free_Page_Linear ;free page table
mov edx,ebx
shr edx,22
mov dword [esi+4*edx],0 ;and clear page directory entry
.first_page:
add ebx,1 shl 22
and ebx,not ((1 shl 22)-1) ;calculate new current address
mov ebp,1 ;set flag
jmp .gen_loop
.endloop1:
popad
ret
end if