Files
TempleOS-Rijn/Kernel/Scheduler.CPP
T
2018-09-08 21:46:02 +02:00

389 lines
8.6 KiB
C++

/*
See $LK,"TempleOS MultiTasking",A="FI:::/Doc/MultiTasking.TXT"$.
Tasks are ordered in a circular queue
by front-to-back window stack order with
the window mgr as the head (paints
the wallpaper). The scheduler is
round-robin. It checking if a task
is ready and runs it or skips it.
Swapping tasks just involves storing and
restoring regs (no disk I/O for virtual
memory and no addr map changes). It is
always fully identity-mapped on all cores.
Tasks can be switched in half a microsecond.
The scheduler checks if a task is
waiting for a certain time or waiting
on a message and skips if not ready.
A task runs until it voluntarily yields
ctrl with a call to $LK,"Yield",A="MN:Yield"$() or gets
preempted by the fixed 1kHz $LK,"JIFFY_FREQ",A="MN:JIFFY_FREQ"$
timer interrupt. See $LK,"SYS_TIMER_HANDLER",A="MN:SYS_TIMER_HANDLER"$.
Tasks can ask not to be preempted with
$LK,"Preempt",A="MN:Preempt"$(ON/OFF). Tasks waiting on I/O
often loop, checking for a status and
$LK,"Yield",A="MN:Yield"$ing. This does not really degrade
performance, but pegs the CPU Load.
The scheduler checks for a few critical
key-strokes such as <CTRL-ALT-X>, which
kills a task; <CTRL-ALT-DEL>, which reboots;
<CTRL-ALT-T>, which changes focus and
<CTRL-ALT-C>, which breaks execution
of a program.
Each core has its own circular task queue.
For AP processors, they have a "Seth" task
which stays in a loop waiting for jobs or
requests to spawn tasks. See $LK,"MPSethServerTask",A="MN:MPSethServerTask"$().
$HL,1$*/
asm {
USE64
// ************************************
TASK_CONTEXT_SAVE::
//OUT: RSI=FS
PUSH RSI
PUSHFD
XOR RSI,RSI
MOV RSI,FS:CTask.addr[RSI]
POP U64 CTask.rflags[RSI]
POP U64 CTask.rsi[RSI]
MOV U64 CTask.rax[RSI],RAX
/*
We divert the stk to the Task memory
and push onto it and divert it back.
It's a little faster.
*/
MOV RAX,RSP
LEA RSP,U64 CTask.r15+8[RSI]
PUSH R15
PUSH R14
PUSH R13
PUSH R12
PUSH R11
PUSH R10
PUSH R9
PUSH R8
PUSH RDI
PUSH RBP
PUSH RBX
PUSH RDX
PUSH RCX
MOV RSP,RAX
RDTSC
SHL RDX,32
ADD RAX,RDX
SUB RAX,U64 CTask.time_slice_start[RSI]
ADD U64 CTask.total_time[RSI],RAX
MOV RAX,U64 CTask.fpu_mmx[RSI]
FXSAVE U64 [RAX]
MOV RDX,U64 CTask.bpt_lst[RSI]
@@05: TEST RDX,RDX
JZ @@10
MOV RDI,U64 CBpt.addr[RDX]
MOV AL,U8 CBpt.val[RDX]
MOV U8 [RDI],AL
MOV RDX,U64 CBpt.next[RDX]
JMP @@05
@@10: RET
// ************************************
_TASK_CONTEXT_RESTORE::
XOR RAX,RAX
INC U64 GS:CCPU.swap_cnter[RAX]
MOV RSI,FS:CTask.addr[RAX]
BT U32 CTask.rflags[RSI],RFLAGf_INT
JNC @@05
BTS U32 GS:CCPU.cpu_flags[RAX],CPUf_RAN_A_TASK
@@05: BT U64 CTask.task_flags[RSI],TASKf_DISABLE_BPTS
JC @@15
MOV RDX,U64 CTask.bpt_lst[RSI]
@@10: TEST RDX,RDX
JZ @@15
MOV RDI,U64 CBpt.addr[RDX]
MOV U8 [RDI],OC_BPT
MOV RDX,U64 CBpt.next[RDX]
JMP @@10
@@15: INC U64 CTask.swap_cnter[RSI]
MOV RAX,U64 CTask.fpu_mmx[RSI]
FXRSTOR U64 [RAX]
RDTSC
SHL RDX,32
ADD RAX,RDX
MOV U64 CTask.time_slice_start[RSI],RAX
MOV RAX,RSP
LEA RSP,U64 CTask.rcx[RSI]
POP RCX
POP RDX
POP RBX
POP RBP
POP RDI
POP R8
POP R9
POP R10
POP R11
POP R12
POP R13
POP R14
POP R15
MOV RSP,RAX
MOV RAX,U64 CTask.rax[RSI]
PUSH CGDT.ds
PUSH U64 CTask.rsp[RSI]
PUSH U64 CTask.rflags[RSI]
PUSH CGDT.cs64
PUSH U64 CTask.rip[RSI]
MOV RSI,U64 CTask.rsi[RSI]
IRET
// ************************************
END_RSI_TASK:
MOV RAX,RSI
CALL SET_FS_BASE
_TASK_END_NOW::
CALL &TaskEnd
MOV RSI,RAX
CALL SET_FS_BASE
JMP I8 RESTORE_RSI_TASK_WITH_KEY_CHECK
RESTORE_RSI_NO_PREEMPT_TASK:
BT U32 [SYS_CTRL_ALT_FLAGS],SYSf_CTRL_ALT_DEL
JC I32 HANDLE_SWAP_KEY_EVENT
XOR RAX,RAX
CMP U64 GS:CCPU.idle_task[RAX],RSI //IDLE TASK HAS PREEMPT-OFF
JNE RESTORE_RSI_TASK_NO_KEY_CHECK
JMP I32 SWAP_IN_SETH_TASK_IF_READY
_YIELD::
PUSHFD
TEST U8 [SYS_SEMAS+SYS_SEMA_SINGLE_USER*SEMA_STRUCT_SIZE],1
JNZ @@05 //If single user, don't change task.
CLI
PUSH RSI
XOR RSI,RSI
MOV RSI,FS:CTask.addr[RSI]
CMP U64 CTask.next_task[RSI],RSI
JNE @@15 //Jmp if not just one task on core.
PUSH RAX
MOV RAX,U64 [SYS_JIFFIES]
CMP U64 CTask.wake_jiffy[RSI],RAX
JG @@10 //If needs to sleep, jmp and swap-out.
POP RAX
POP RSI
@@05: POPFD
RET
@@10: POP RAX
@@15: POP RSI
CALL TASK_CONTEXT_SAVE
MOV EBX,U32 _RET
MOV U64 CTask.rip[RSI],RBX
POP U64 CTask.rflags[RSI]
MOV U64 CTask.rsp[RSI],RSP
RESTORE_NEXT_RSI_TASK:
MOV RSI,U64 CTask.next_task[RSI]
RESTORE_RSI_TASK_WITH_KEY_CHECK:
TEST U64 [SYS_CTRL_ALT_FLAGS],1<<SYSf_CTRL_ALT_DEL|
1<<SYSf_CTRL_ALT_TAB|1<<SYSf_CTRL_ALT_X|1<<SYSf_CTRL_ALT_C
JNZ HANDLE_SWAP_KEY_EVENT
RESTORE_RSI_TASK_NO_KEY_CHECK:
@@20: BT U64 CTask.task_flags[RSI],TASKf_KILL_TASK
JC I32 END_RSI_TASK
TEST U64 CTask.task_flags[RSI],1<<TASKf_AWAITING_MSG|1<<TASKf_SUSPENDED
JNZ @@25
MOV RAX,U64 [SYS_JIFFIES]
CMP U64 CTask.wake_jiffy[RSI],RAX
JG @@25 //Jmp if not ready, yet.
CMP U32 CTask.task_in_que_signature[RSI],TASK_IN_QUE_SIGNATURE_VAL
JNE SWAP_IN_SETH_TASK_IF_READY
MOV RAX,RSI
CALL SET_FS_BASE
JMP I32 _TASK_CONTEXT_RESTORE
@@25: MOV RSI,U64 CTask.next_task[RSI]
XOR RAX,RAX
CMP U64 GS:CCPU.seth_task[RAX],RSI
JNE @@20 //Jmp if not Seth
BTR U32 GS:CCPU.cpu_flags[RAX],CPUf_RAN_A_TASK
JC @@20 //Jmp if had chance for IRQ already
MOV RAX,U64 GS:CCPU.idle_task[RAX]
MOV RSP,U64 CTask.stk[RAX]
ADD RSP,DFT_STK+CTaskStk.stk_base //Rst to top
CALL SET_FS_BASE
STI //Swap-in idle task so we can unmask IRQs.
HLT
SYS_IDLE_PT::
CLI
SWAP_IN_SETH_TASK_IF_READY:
XOR RAX,RAX
MOV RSI,GS:CCPU.seth_task[RAX]
JMP I32 RESTORE_RSI_TASK_WITH_KEY_CHECK
HANDLE_SWAP_KEY_EVENT:
MOV RAX,RSI
CALL SET_FS_BASE
XOR RAX,RAX
MOV RAX,GS:CCPU.num[RAX]
TEST RAX,RAX
JNZ I32 RESTORE_RSI_TASK_NO_KEY_CHECK
MOV EAX,U32 SYS_CTRL_ALT_FLAGS
LOCK
BTR U32 [RAX],SYSf_CTRL_ALT_DEL
JC I32 &Reboot
LOCK
BTR U32 [RAX],SYSf_CTRL_ALT_TAB
JNC @@05
PUSH RSI
MOV RSI,U64 [SYS_FOCUS_TASK]
MOV U64 [SYS_FOCUS_TASK],0
CALL FOCUS_RSI_NEXT_USER
POP RSI
JMP I32 RESTORE_FS_TASK_WITH_KEY_CHECK
@@05: LOCK
BTR U32 [RAX],SYSf_CTRL_ALT_X
JC END_FOCUS_USER
LOCK
BTR U32 [RAX],SYSf_CTRL_ALT_C
JNC I32 RESTORE_RSI_TASK_WITH_KEY_CHECK
BREAK_FOCUS_USER:
MOV RSI,U64 [SYS_FOCUS_TASK]
TEST RSI,RSI
JZ SWAP_IN_SETH_TASK_IF_READY
BT U64 CTask.win_inhibit[RSI],WIf_FOCUS
JC I32 RESTORE_RSI_TASK_NO_KEY_CHECK
LOCK
BTR U64 CTask.task_flags[RSI],TASKf_BREAK_LOCKED
JNC @@10
LOCK
BTS U64 CTask.task_flags[RSI],TASKf_PENDING_BREAK
JMP I32 RESTORE_RSI_TASK_NO_KEY_CHECK
@@10: MOV RAX,&SysThrowBreak
MOV U64 CTask.rip[RSI],RAX
BT U64 CTask.task_flags[RSI],TASKf_BREAK_TO_SHIFT_ESC
JC @@15
//We do these two now, in case interrupt happens
MOV U64 CTask.wake_jiffy[RSI],0
PUSH RSI
CALL &TaskRstAwaitingMsg
@@15: JMP I32 RESTORE_RSI_TASK_NO_KEY_CHECK
END_FOCUS_USER:
MOV RSI,U64 [SYS_FOCUS_TASK]
MOV U64 [SYS_FOCUS_TASK],0
PUSH RSI
CALL FOCUS_RSI_NEXT_USER
POP RSI
TEST RSI,RSI
JZ I32 SWAP_IN_SETH_TASK_IF_READY
MOV RAX,RSI
CALL SET_FS_BASE
BT U64 CTask.win_inhibit[RSI],WIf_FOCUS
JC I32 RESTORE_RSI_TASK_WITH_KEY_CHECK
LOCK
BTS U64 CTask.task_flags[RSI],TASKf_KILL_TASK
JMP I32 END_RSI_TASK
RESTORE_FS_TASK_WITH_KEY_CHECK:
XOR RSI,RSI
MOV RSI,FS:CTask.addr[RSI]
JMP I32 RESTORE_RSI_TASK_WITH_KEY_CHECK
FOCUS_RSI_NEXT_USER:
TEST RSI,RSI
JNZ @@20
MOV ESI,U32 SYS_FIXED_AREA+CSysFixedArea.adam
@@20: MOV RDI,RSI
MOV RSI,U64 CTask.next_task[RSI]
@@25: BT U64 CTask.win_inhibit[RSI],WIf_FOCUS
JC @@30
CMP U64 [SYS_FOCUS_TASK],RSI
JE @@30
MOV U64 [SYS_FOCUS_TASK],RSI
MOV RAX,U64 [SYS_EXTERN_TABLE]
MOV RAX,U64 EXT_WIN_TO_TOP*8[RAX]
TEST RAX,RAX
JZ @@35
PUSH TRUE
PUSH RSI
CALL RAX
JMP @@35
@@30: MOV RSI,U64 CTask.next_task[RSI]
CMP RSI,RDI
JNE @@25
MOV U64 [SYS_FOCUS_TASK],0
@@35: RET
}
_extern _TASK_CONTEXT_RESTORE U0 TaskContextRestore();
_extern _YIELD U0 Yield();
_extern _TASK_END_NOW U0 TaskEndNow();
U0 TaskQueIns(CTask *task,CTask *pred=NULL)
{//Insert a task in the scheduler running task queue.
//You have no business with this, probably.
CTask *last;
PUSHFD
CLI
if (!pred) pred=Fs;
last=pred->last_task;
last->next_task=pred->last_task=task;
task->last_task=last;
task->next_task=pred;
task->task_in_que_signature=TASK_IN_QUE_SIGNATURE_VAL;
POPFD
}
U0 TaskQueRem(CTask *task)
{//Remove a task from the scheduler running task queue.
//Use $LK,"Suspend",A="MN:Suspend"$().
CTask *next,*last;
PUSHFD
CLI
task->task_in_que_signature=0;
next=task->next_task;
last=task->last_task;
last->next_task=next;
next->last_task=last;
POPFD
}
U0 TaskQueInsChild(CTask *task)
{
CTask *last,*pred;
PUSHFD
CLI
pred=task->parent_task->last_child_task;
last=pred->last_sibling_task;
last->next_sibling_task=pred->last_sibling_task=task;
task->last_sibling_task=last;
task->next_sibling_task=pred;
POPFD
}