kolibrios-fun/kernel/trunk/core/sys32.inc
Jurgen 5eb750c289 1. Edit procedure check exception 12 (overflow stack)
2. Edit func 68,24
3. Add proc "control exception"
4. Add subfuncs func 51 (GetPriorityThread, SetPriorityThread,GetCurrentThreadId)
5. Add info in ReferenceFunc(rus)

git-svn-id: svn://kolibrios.org@10002 a494cfbc-eb01-0410-851d-a64ba20cac60
2024-03-23 19:19:24 +00:00

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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; ;;
;; Copyright (C) KolibriOS team 2004-2022. All rights reserved. ;;
;; Distributed under terms of the GNU General Public License. ;;
;; ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
$Revision$
struct EXCEPT_STACK
RegEIP dd ?
ExcCode dd ? ; only exception 12 overflow stack
OldESP dd ?
RegCR2 dd ?
LockAccess dd ?
ends
align 4 ;3A08
build_interrupt_table:
mov edi, idts
mov esi, sys_int
mov ecx, 0x40
mov eax, (10001110b shl 24) + os_code
@@:
movsw ; low word of code-entry
stosd ; interrupt gate type : os_code selector
movsw ; high word of code-entry
loop @b
movsd ; copy low dword of trap gate for int 0x40
movsd ; copy high dword of trap gate for int 0x40
mov ecx, 23
mov eax, (10001110b shl 24) + os_code
@@:
movsw ; low word of code-entry
stosd ; interrupt gate type : os_code selector
movsw ; high word of code-entry
loop @b
lidt [esi]
ret
iglobal
align 4
sys_int:
; exception handlers addresses (for interrupt gate construction)
dd e0,e1,e2,e3,e4,e5,e6,except_7 ; SEE: core/fpu.inc
dd e8,e9,e10,e11,e12,e13,page_fault_exc,e15
dd e16, e17,e18, e19
times 12 dd unknown_interrupt ;int_20..int_31
; interrupt handlers addresses (for interrupt gate construction)
; 0x20+ are IRQ handlers
dd irq0
rept 12 irqn:1 \{dd irq_serv.irq_\#irqn\}
dd irqD
rept 18 irqn:14 \{dd irq_serv.irq_\#irqn\}
; int_0x40 gate trap (for directly copied)
dw i40 and 0xFFFF, os_code, 11101111b shl 8, i40 shr 16
rept 23 irqn:33 \{dd irq_serv.irq_\#irqn\}
idtreg: ; data for LIDT instruction (!!! must be immediately below sys_int data)
dw 2*($-sys_int-4)-1
dd idts ; 0x8000B100
dw 0 ; alignment
msg_fault_sel dd msg_exc_8,msg_exc_u,msg_exc_a,msg_exc_b
dd msg_exc_c,msg_exc_d,msg_exc_e,msg_exc_u
dd msg_exc_u,msg_exc_11
msg_exc_8 db "Double fault", 0
msg_exc_u db "Undefined Exception", 0
msg_exc_a db "Invalid TSS", 0
msg_exc_b db "Segment not present", 0
msg_exc_c db "Stack fault", 0
msg_exc_d db "General protection fault", 0
msg_exc_e db "Page fault", 0
msg_exc_11 db "Alignment Check", 0
if lang eq sp
include 'core/sys32-sp.inc'
else
msg_sel_ker db "kernel", 0
msg_sel_app db "application", 0
end if
endg
macro save_ring3_context {
pushad
}
macro restore_ring3_context {
popad
}
macro exc_wo_code [num] {
e#num :
save_ring3_context
mov bl, num
jmp exc_c
} exc_wo_code 0,1,2,3,4,5,6,15,16,19
macro exc_w_code [num] {
e#num :
add esp, 4
save_ring3_context
mov bl, num
jmp exc_c
} exc_w_code 8,9,10,11,12,13,17,18
uglobal
pf_err_code dd ?
endg
page_fault_exc: ; foolproof: selectors are clobbered ...
pop [ss:pf_err_code] ; actually, until the next #PF
cmp edi, CONTROL_EXCEPTION ; equ 'EXPT'
jne .no_ctrl_exc
bt dword [esp], 31
jc .setret
test esi, esi
jl .no_ctrl_exc
.setret:
mov [esp], esi
iret
.no_ctrl_exc:
save_ring3_context
mov bl, 14
exc_c: ; exceptions (all but 7th - #NM)
; stack frame when exception/interrupt from ring3 + pushad (i.e right here)
reg_ss equ esp+0x30
reg_esp3 equ esp+0x2C
reg_eflags equ esp+0x28
reg_cs3 equ esp+0x24
reg_eip equ esp+0x20
; this if frame from pushad
reg_eax equ esp+0x1C
reg_ecx equ esp+0x18
reg_edx equ esp+0x14
reg_ebx equ esp+0x10
reg_esp0 equ esp+0x0C
reg_ebp equ esp+0x08
reg_esi equ esp+0x04
reg_edi equ esp+0x00
mov ax, app_data ; exception
mov ds, ax ; load proper values
mov es, ax ; to registers
cld ; clear the direction flag
movzx ebx, bl
; redirect to V86 manager? (EFLAGS & 0x20000) != 0?
test byte[reg_eflags+2], 2
jnz v86_exc_c
cmp bl, 14 ; #PF
jne @f
call page_fault_handler ; SEE: core/memory.inc
@@:
mov esi, [current_slot]
btr [esi + APPDATA.except_mask], ebx
jnc @f
mov eax, [esi + APPDATA.exc_handler]
test eax, eax
jnz IRetToUserHook
@@:
cli
mov eax, [esi + APPDATA.debugger_slot]
test eax, eax
jnz .debug
; not debuggee => say error and terminate
call show_error_parameters ; this function output in edx = current_slot
sti
mov [edx + APPDATA.state], TSTATE_TERMINATING
call wakeup_osloop
call change_task
; If we're here, then the main OS thread has crashed before initializing IDLE thread.
; Or they both have crashed. Anyway, things are hopelessly broken.
hlt
jmp $-1
.debug:
; we are debugged process, notify debugger and suspend ourself
; eax=debugger PID
mov ecx, 1 ; debug_message code=other_exception
cmp bl, 1 ; #DB
jne .notify ; notify debugger and suspend ourself
mov ebx, dr6 ; debug_message data=DR6_image
xor edx, edx
mov dr6, edx
mov edx, dr7
mov cl, not 8
.l1:
shl dl, 2
jc @f
and bl, cl
@@:
sar cl, 1
jc .l1
mov cl, 3 ; debug_message code=debug_exception
.notify:
push ebx ; debug_message data
mov ebx, [current_slot]
push [ebx + APPDATA.tid] ; PID
push ecx ; debug_message code ((here: ecx==1/3))
mov cl, 12 ; debug_message size
call debugger_notify ;; only ONE using, inline ??? SEE: core/debug.inc
add esp, 12
mov edx, [current_slot]
mov [edx + APPDATA.state], TSTATE_RUN_SUSPENDED
call change_task ; SEE: core/shed.inc
restore_ring3_context
iretd
IRetToUserHook:
cmp ebx, 12
je .ex_stack
cmp ebx, 14
jne .nostack
mov ecx, cr2
sub ecx, [reg_esp3]
jg .nostack
add ecx, 1000h
jl .nostack
.ex_stack:
mov ecx, [esi+APPDATA.exc_reserve_stack]
test ecx, ecx
jle .nostack
xchg edi, eax
sub ecx, sizeof.EXCEPT_STACK
push ebx
push 1
pop ebx
.lock:
lock bts [ecx+EXCEPT_STACK.LockAccess], 0
jnc .lock1
call delay_hs_unprotected
jmp .lock
.lock1:
pop ebx
cmp ebx, 14
jne .ex12
btr [esi+APPDATA.except_mask], 12
jc .ex_stack1
xchg eax, edi
jmp .nostack
.ex_stack1:
bts [esi+APPDATA.except_mask], ebx
dec ebx
dec ebx
.ex12:
mov [ecx+EXCEPT_STACK.ExcCode], ebx
mov eax, ecx
xchg [reg_esp3], eax
mov [ecx+EXCEPT_STACK.OldESP], eax
mov eax, cr2
mov [ecx+EXCEPT_STACK.RegCR2], eax
xchg edi, [reg_eip]
mov [ecx+EXCEPT_STACK.RegEIP], edi
jmp .end
.nostack:
xchg eax, [reg_eip]
sub dword[reg_esp3], 8
mov edi, [reg_esp3]
stosd
mov [edi], ebx
.end:
restore_ring3_context
; simply return control to interrupted process
unknown_interrupt:
iretd
;-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
; bl - error vector
show_error_parameters:
cmp bl, 0x06
jnz .no_ud
push ebx
mov ebx, ud_user_message
mov ebp, notifyapp
call fs_execute_from_sysdir_param
pop ebx
.no_ud:
mov edx, [current_slot];not scratched below
if lang eq sp
DEBUGF 1, "K : Proceso - terminado forzado PID: %x [%s]\n", [edx + APPDATA.tid], [current_slot]
else
DEBUGF 1, "K : Process - forced terminate PID: %x [%s]\n", [edx + APPDATA.tid], [current_slot]
end if
cmp bl, 0x08
jb .l0
cmp bl, 0x11
jbe .l1
.l0:
mov bl, 0x09
.l1:
mov eax, [msg_fault_sel+ebx*4 - 0x08*4]
DEBUGF 1, "K : %s\n", eax
mov eax, [reg_cs3+4]
mov edi, msg_sel_app
mov ebx, [reg_esp3+4]
cmp eax, app_code
je @f
mov edi, msg_sel_ker
mov ebx, [reg_esp0+4]
@@:
DEBUGF 1, "K : EAX : %x EBX : %x ECX : %x\n", [reg_eax+4], [reg_ebx+4], [reg_ecx+4]
DEBUGF 1, "K : EDX : %x ESI : %x EDI : %x\n", [reg_edx+4], [reg_esi+4], [reg_edi+4]
DEBUGF 1, "K : EBP : %x EIP : %x ESP : %x\n", [reg_ebp+4], [reg_eip+4], ebx
DEBUGF 1, "K : Flags : %x CS : %x (%s)\n", [reg_eflags+4], eax, edi
DEBUGF 1, "K : Stack dump:\n"
push eax ebx ecx edx
call .check_ESP
test eax, eax
jnz .error_ESP
DEBUGF 1, "K : [ESP+00]: %x",[ebx]
add ebx, 4
call .check_ESP
test eax, eax
jnz .error_ESP
DEBUGF 1, " [ESP+04]: %x",[ebx]
add ebx, 4
call .check_ESP
test eax, eax
jnz .error_ESP
DEBUGF 1, " [ESP+08]: %x\n",[ebx]
add ebx, 4
call .check_ESP
test eax, eax
jnz .error_ESP
DEBUGF 1, "K : [ESP+12]: %x",[ebx]
add ebx, 4
call .check_ESP
test eax, eax
jnz .error_ESP
DEBUGF 1, " [ESP+16]: %x",[ebx]
add ebx, 4
call .check_ESP
test eax, eax
jnz .error_ESP
DEBUGF 1, " [ESP+20]: %x\n",[ebx]
add ebx, 4
call .check_ESP
test eax, eax
jnz .error_ESP
DEBUGF 1, "K : [ESP+24]: %x",[ebx]
add ebx, 4
call .check_ESP
test eax, eax
jnz .error_ESP
DEBUGF 1, " [ESP+28]: %x",[ebx]
add ebx, 4
call .check_ESP
test eax, eax
jnz .error_ESP
DEBUGF 1, " [ESP+32]: %x\n",[ebx]
pop edx ecx ebx eax
ret
.error_ESP:
pop edx ecx ebx eax
DEBUGF 1, "\n"
DEBUGF 1, "K : Unexpected end of the stack\n"
ret
;--------------------------------------
.check_ESP:
push ebx
shr ebx, 12
mov ecx, ebx
shr ecx, 10
mov edx, [master_tab + ecx*4]
test edx, PG_READ
jz .fail ; page table is not created
; incorrect address in the program
mov eax, [page_tabs + ebx*4]
test eax, 2
jz .fail ; address not reserved for use. error
pop ebx
xor eax, eax
ret
.fail:
pop ebx
xor eax, eax
dec eax
ret
;-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
restore reg_ss
restore reg_esp3
restore reg_eflags
restore reg_cs
restore reg_eip
restore reg_eax
restore reg_ecx
restore reg_edx
restore reg_ebx
restore reg_esp0
restore reg_ebp
restore reg_esi
restore reg_edi
align 4
lock_application_table:
push eax ecx edx
mov ecx, application_table_mutex
call mutex_lock
mov eax, [current_slot]
mov eax, [eax + APPDATA.tid]
mov [application_table_owner], eax
pop edx ecx eax
ret
align 4
unlock_application_table:
push eax ecx edx
mov [application_table_owner], 0
mov ecx, application_table_mutex
call mutex_unlock
pop edx ecx eax
ret
; sysfn 64 implementation
align 4
sys_resize_app_memory:
; in: eax = 64 - function number
; ebx = 1 - number of its only subfunction
; ecx = new amount of memory
; out:
; eax = 0 - success
; eax = 1 - out of memory
; cmp eax,1
dec ebx
jnz .no_application_mem_resize
mov eax, [pg_data.pages_free]
shl eax, 12
cmp eax, ecx
jae @f
xor eax, eax
inc eax
jmp .store_result
@@:
stdcall new_mem_resize, ecx
.store_result:
mov [esp + SYSCALL_STACK.eax], eax
.no_application_mem_resize:
ret
iglobal
; process_terminating db 'K : Process - terminating',13,10,0
; process_terminated db 'K : Process - done',13,10,0
msg_obj_destroy db 'K : destroy app object',13,10,0
endg
; param
; esi= slot
align 4
terminate: ; terminate application
destroy_thread:
.slot equ esp+4 ;locals
.process equ esp ;ptr to parent process
push esi ;save .slot
shl esi, BSF sizeof.APPDATA
mov edx, [SLOT_BASE + esi + APPDATA.process]
test edx, edx
jnz @F
mov [SLOT_BASE + esi + APPDATA.state], TSTATE_FREE
pop esi
ret
@@:
push edx ;save .process
lea edx, [SLOT_BASE + esi]
call scheduler_remove_thread
call lock_application_table
; if the process is in V86 mode...
mov eax, [.slot]
shl eax, BSF sizeof.APPDATA
mov esi, [SLOT_BASE + eax + APPDATA.pl0_stack]
add esi, RING0_STACK_SIZE
cmp [SLOT_BASE + eax + APPDATA.saved_esp0], esi
jz .nov86
; ...it has page directory for V86 mode
mov esi, [SLOT_BASE + eax + APPDATA.saved_esp0]
mov ecx, [esi+4]
mov [SLOT_BASE + eax + APPDATA.process], ecx
; ...and I/O permission map for V86 mode
mov ecx, [esi+12]
mov [SLOT_BASE + eax + APPDATA.io_map], ecx
mov ecx, [esi+8]
mov [SLOT_BASE + eax + APPDATA.io_map+4], ecx
.nov86:
; destroy per-thread kernel objects
mov esi, [.slot]
shl esi, BSF sizeof.APPDATA
add esi, SLOT_BASE + APP_OBJ_OFFSET
@@:
mov eax, [esi + APPOBJ.fd]
test eax, eax
jz @F
cmp eax, esi
je @F
push esi
call [eax + APPOBJ.destroy]
DEBUGF 1,"%s",msg_obj_destroy
pop esi
jmp @B
@@:
mov esi, [.slot]
cmp [fpu_owner], esi ; if user fpu last -> fpu user = 2
jne @F
mov [fpu_owner], 2
mov eax, [SLOT_BASE + sizeof.APPDATA*2 + APPDATA.fpu_state]
clts
bt [cpu_caps], CAPS_SSE
jnc .no_SSE
fxrstor [eax]
jmp @F
.no_SSE:
fnclex
frstor [eax]
@@:
mov [KEY_COUNT], byte 0 ; empty keyboard buffer
mov [BTN_COUNT], byte 0 ; empty button buffer
; remove defined hotkeys
mov eax, hotkey_list
.loop:
cmp [eax+8], esi
jnz .cont
mov ecx, [eax]
jecxz @f
push dword [eax+12]
pop dword [ecx+12]
@@:
mov ecx, [eax+12]
push dword [eax]
pop dword [ecx]
xor ecx, ecx
mov [eax], ecx
mov [eax+4], ecx
mov [eax+8], ecx
mov [eax+12], ecx
.cont:
add eax, 16
cmp eax, hotkey_list+256*16
jb .loop
; get process PID
mov eax, esi
shl eax, BSF sizeof.APPDATA
mov eax, [eax + SLOT_BASE + APPDATA.tid]
; compare current lock input with process PID
cmp eax, [PID_lock_input]
jne @f
xor eax, eax
mov [PID_lock_input], eax
@@:
; remove hotkeys in buffer
mov eax, hotkey_buffer
.loop2:
cmp [eax], esi
jnz .cont2
and dword [eax+4], 0
and dword [eax], 0
.cont2:
add eax, 8
cmp eax, hotkey_buffer+120*8
jb .loop2
mov ecx, esi ; remove buttons
.bnewba2:
mov edi, [BTN_ADDR]
mov eax, edi
cld
movzx ebx, word [edi]
inc bx
.bnewba:
dec bx
jz .bnmba
add eax, 0x10
cmp cx, [eax]
jnz .bnewba
pusha
mov ecx, ebx
inc ecx
shl ecx, 4
mov ebx, eax
add eax, 0x10
call memmove
dec dword [edi]
popa
jmp .bnewba2
.bnmba:
pusha ; save window coordinates for window restoring
cld
shl esi, BSF sizeof.WDATA
add esi, window_data
mov eax, [esi + WDATA.box.left]
mov [draw_limits.left], eax
add eax, [esi + WDATA.box.width]
mov [draw_limits.right], eax
mov eax, [esi + WDATA.box.top]
mov [draw_limits.top], eax
add eax, [esi + WDATA.box.height]
mov [draw_limits.bottom], eax
xor eax, eax
mov edi, esi
mov ecx, sizeof.WDATA/4
rep stosd
popa
; debuggee test
pushad
mov edi, esi
shl edi, BSF sizeof.APPDATA
mov eax, [SLOT_BASE + edi + APPDATA.debugger_slot]
test eax, eax
jz .nodebug
movi ecx, 8
push dword [SLOT_BASE + edi + APPDATA.tid]; PID
push 2
call debugger_notify
pop ecx
pop ecx
.nodebug:
popad
mov ebx, [.slot]
shl ebx, BSF sizeof.APPDATA
push ebx
mov ebx, [SLOT_BASE + ebx + APPDATA.pl0_stack]
stdcall kernel_free, ebx
pop ebx
mov ebx, [SLOT_BASE + ebx + APPDATA.cur_dir]
stdcall kernel_free, ebx
mov edi, [.slot]
shl edi, BSF sizeof.APPDATA
add edi, SLOT_BASE
mov eax, [edi + APPDATA.io_map]
cmp eax, [SLOT_BASE + sizeof.APPDATA+APPDATA.io_map]
je @F
call free_page
@@:
mov eax, [edi+APPDATA.io_map+4]
cmp eax, [SLOT_BASE+sizeof.APPDATA+APPDATA.io_map+4]
je @F
call free_page
@@:
lea ebx, [edi + APPDATA.list]
list_del ebx ;destroys edx, ecx
; activate window
movzx eax, word [WIN_STACK + esi*2]
cmp eax, [thread_count]
jne .dont_activate
pushad
.check_next_window:
dec eax
cmp eax, 1
jbe .nothing_to_activate
lea esi, [WIN_POS + eax*2]
movzx edi, word [esi] ; edi = process
shl edi, BSF sizeof.APPDATA
cmp [SLOT_BASE + edi + APPDATA.state], TSTATE_FREE ; skip free slots
je .check_next_window
shr edi, (BSF sizeof.APPDATA - BSF sizeof.WDATA)
add edi, window_data
; \begin{diamond}[19.09.2006]
; skip minimized windows
test [edi + WDATA.fl_wstate], WSTATE_MINIMIZED
jnz .check_next_window
; \end{diamond}
call waredraw
.nothing_to_activate:
popad
.dont_activate:
push esi ; remove hd1 & cd & flp reservation
shl esi, BSF sizeof.APPDATA
mov esi, [SLOT_BASE + esi + APPDATA.tid]
cmp [cd_status], esi
jnz @f
call free_cd_channel
and [cd_status], 0
@@:
pop esi
cmp [bgrlockpid], esi
jnz @f
and [bgrlockpid], 0
and [bgrlock], 0
@@:
pusha ; remove all port reservations
mov edx, esi
shl edx, BSF sizeof.APPDATA
mov edx, [SLOT_BASE + edx + APPDATA.tid]
.rmpr0:
mov esi, [RESERVED_PORTS]
test esi, esi
jz .rmpr9
.rmpr3:
mov edi, esi
shl edi, 4
add edi, RESERVED_PORTS
cmp edx, [edi]
je .rmpr4
dec esi
jnz .rmpr3
jmp .rmpr9
.rmpr4:
mov ecx, 256
sub ecx, esi
shl ecx, 4
mov esi, edi
add esi, 16
cld
rep movsb
dec dword [RESERVED_PORTS]
jmp .rmpr0
.rmpr9:
popa
; clearing APPDATA structure this thread
pushad
mov edi, esi
shl edi, BSF sizeof.APPDATA
add edi, SLOT_BASE
mov eax, 0x20202020
stosd
stosd
stosd
mov ecx, 244/4
xor eax, eax
rep stosd
popad
mov edi, esi ; do not run this process slot
shl edi, BSF sizeof.APPDATA
mov [SLOT_BASE + edi + APPDATA.state], TSTATE_FREE
; debugger test - terminate all debuggees
mov eax, 2
mov ecx, SLOT_BASE + 2*sizeof.APPDATA + APPDATA.debugger_slot
.xd0:
cmp eax, [thread_count]
ja .xd1
cmp dword [ecx], esi
jnz @f
and dword [ecx], 0
pushad
xchg eax, ecx
mov ebx, 2
call sys_system
popad
@@:
inc eax
add ecx, sizeof.APPDATA
jmp .xd0
.xd1:
;release slot
bts [thr_slot_map], esi
mov ecx, [.process]
lea eax, [ecx + PROC.thr_list]
cmp eax, [eax + LHEAD.next]
jne @F
call destroy_process.internal
@@:
sti ; .. and life goes on
mov eax, [draw_limits.left]
mov ebx, [draw_limits.top]
mov ecx, [draw_limits.right]
mov edx, [draw_limits.bottom]
call calculatescreen
xor eax, eax
xor esi, esi
call redrawscreen
call unlock_application_table
;mov esi,process_terminated
;call sys_msg_board_str
add esp, 8
ret
restore .slot
restore .process
; Three following procedures are used to guarantee that
; some part of kernel code will not be terminated from outside
; while it is running.
; Note: they do not protect a thread from terminating due to errors inside
; the thread; accessing a nonexisting memory would still terminate it.
; First two procedures must be used in pair by thread-to-be-protected
; to signal the beginning and the end of an important part.
; It is OK to have nested areas.
; The last procedure must be used by outside wanna-be-terminators;
; if it is safe to terminate the given thread immediately, it returns eax=1;
; otherwise, it returns eax=0 and notifies the target thread that it should
; terminate itself when leaving a critical area (the last critical area if
; they are nested).
; Implementation. Those procedures use one dword in APPDATA for the thread,
; APPDATA.terminate_protection.
; * The upper bit is 1 during normal operations and 0 when terminate is requested.
; * Other bits form a number = depth of critical regions,
; plus 1 if the upper bit is 1.
; * When this dword goes to zero, the thread should be destructed,
; and the procedure in which it happened becomes responsible for destruction.
; Enter critical area. Called by thread which wants to be protected.
proc protect_from_terminate
mov edx, [current_slot]
; Atomically increment depth of critical areas and get the old value.
mov eax, 1
lock xadd [edx + APPDATA.terminate_protection], eax
; If the old value was zero, somebody has started to terminate us,
; so we are destructing and cannot do anything protected.
; Otherwise, return to the caller.
test eax, eax
jz @f
ret
@@:
; Wait for somebody to finish us.
call change_task
jmp @b
endp
; Leave critical area. Called by thread which wants to be protected.
proc unprotect_from_terminate
mov edx, [current_slot]
; Atomically decrement depth of critical areas.
lock dec [edx + APPDATA.terminate_protection]
; If the result of decrement is zero, somebody has requested termination,
; but at that moment we were inside a critical area; terminate now.
jz sys_end
; Otherwise, return to the caller.
ret
endp
; Request termination of thread identified by edx = SLOT_BASE + slot*sizeof.APPDATA.
; Called by anyone.
proc request_terminate
xor eax, eax ; set return value
; Atomically clear the upper bit. If it was already zero, then
; somebody has requested termination before us, so just exit.
lock btr [edx + APPDATA.terminate_protection], 31
jnc .unsafe
; Atomically decrement depth of critical areas.
lock dec [edx + APPDATA.terminate_protection]
; If the result of decrement is nonzero, the target thread is inside a
; critical area; leave termination to leaving that area.
jnz .unsafe
; Otherwise, it is safe to kill the target now and the caller is responsible
; for this. Return eax=1.
inc eax
.unsafe:
ret
endp