AMProcessBasicImpl.mesa
Copyright © 1984 by Xerox Corporation. All rights reserved.
Russ Atkinson, July 19, 1984 5:32:00 pm PDT
Andrew Birrell, September 16, 1983 11:29 am
Paul Rovner, August 10, 1983 12:04 pm
DIRECTORY
AMProcessBasic USING[ Faulted, GFTable, GFTableObject, State ],
Basics USING[ LongNumber],
BootFileChanges USING[ IsVacant],
DebuggerSwap USING[ Frozen, freezeesTable, freezer],
Loader USING[ MakeProcedureResident ],
PrincOps --USING just about everything--,
PrincOpsUtils USING[
Alloc, DisableInterrupts, EnableAndRequeue, EnableInterrupts, Free, GetReturnFrame, LongCOPY, MyGlobalFrame, MyLocalFrame, PsbHandleToIndex, PsbIndexToHandle, ReadPSB, Requeue],
Process USING[ Pause ],
TrapSupport USING[ opTrapTable ],
VM USING[ PageNumberForAddress, PageNumber, Pin, Unpin],
WorldVM USING[
Address, AddressFault, CopyRead, CopyWrite, LocalWorld, Lock, Long, LongRead, Read, Unlock, World, Write],
WVMPrivate USING[ Patch ];
AMProcessBasicImpl: MONITOR
IMPORTS
BootFileChanges, DebuggerSwap, Loader, PrincOpsUtils, Process, VM, WorldVM, WVMPrivate
EXPORTS AMProcessBasic
SHARES DebuggerSwap =
BEGIN
Innocent reader beware! This module contains very delicate code. Much of it is
executed with interrupts disabled. When disabled, the following constraints are
obeyed: all code is resident, all data is resident, no procedure calls (except to INLINEs).
Consider very carefully before modifying any of this module.
PSBI: TYPE = PrincOps.PsbIndex;
******** Part 1: Aborting ********
zTrapME: PrincOps.op = 176B;
zTrapMRE: PrincOps.op = 177B;
--AMProcessBasic.--Abort: PUBLIC PROC[world: WorldVM.World, psbi: PSBI] =
BEGIN
state: AMProcessBasic.State;
frozen: BOOL;
processFrame: PrincOps.FrameHandle;
trapFrame: POINTER TO local PrincOps.Frame = AbortFrame[];
-- lock out anyone else from modifying victim process --
Set[psbi];
[frozen: frozen, state: state, processFrame: processFrame] ←
InfoFromPSB[world, psbi, FALSE ! UNWIND => PrincOpsUtils.Free[trapFrame]];
IF state = dead THEN { PrincOpsUtils.Free[trapFrame]; RETURN };
-- now, world and psbi are locked --
[] ← GetPSB[psbi, world, TRUE];
IF frozen OR world # local
THEN { Unlock[world]; PrincOpsUtils.Free[trapFrame] }
ELSE BEGIN
ENABLE UNWIND => Clear[psbi];
SetPsbFrame[world, psbi, trapFrame];
trapFrame.returnlink.frame ← processFrame;
disable process's timeout so it doesn't change queues during Dequeue.
PrincOps.PDA[PrincOps.PDA.timeout][psbi] ← PrincOps.NoTimeout;
TEMP until microcode uses timeout vector:
PrincOps.PDA.block[psbi].--timeout--mds ← PrincOps.NoTimeout;
Unlock[world];
IF (state = waitingCV OR state = waitingML) AND NOT frozen
THEN Dequeue[world, psbi, processFrame];
END;
-- world is unlocked and process has been requeued from any CV or ML queue --
Clear[psbi];
END--DoAbort--;
Dequeue: PROC[world: WorldVM.World, psbi: PSBI, frame: PrincOps.FrameHandle] =
BEGIN
-- Only implemented for world = local --
This procedure will remove a process from a CV or ML queue and requeue it onto ready list.
The process must already have bee forced into a trap so it will not return from the
frame where it was waiting.
World is not frozen at entry, nor at exit.
style: { ME, MRE };
wordAddr: LONG POINTER;
offset: [0..1];
op, trap: PrincOps.op;
queue: LONG POINTER TO PrincOps.Queue;
set the tangle-trap
DO code: LONG POINTER = frame.accesslink.code.longbase;
pc: PrincOps.BytePC ← [frame.pc-1];
Fetch: PROC =
BEGIN
word: PrincOps.InstWord;
wordAddr ← code + pc / 2;
offset ← pc MOD 2;
word ← wordAddr^;
op ← IF offset = 0 THEN word.evenbyte ELSE word.oddbyte;
END;
Fetch[];
SELECT op FROM
PrincOps.zME => { style ← ME; trap ← zTrapME };
PrincOps.zMRE => { style ← MRE; trap ← zTrapMRE };
PrincOps.zMXW =>
BEGIN
style ← MRE;
trap ← zTrapMRE;
THROUGH [1..1000]
DO pc ← [pc + OpcodeLengths[op]]; Fetch[]; IF op = PrincOps.zMRE THEN EXIT;
REPEAT FINISHED => ERROR
ENDLOOP;
END;
zTrapME, zTrapMRE =>
{ Process.Pause[1]; LOOP --obscure: some other process being patched at same place--};
ENDCASE => { Clear[psbi]; RETURN }; -- process will become ready by itself --
IF WVMPrivate.Patch[world: world, addr: LOOPHOLE[wordAddr, WorldVM.Address],
offset: offset, byte: trap] = op
THEN EXIT;
-- otherwise, someone else is patching, so look again! --
ENDLOOP;
-- call copy of victim's frame, to evaluate queue pointers --
BEGIN
newFrame: PrincOps.FrameHandle;
state: PrincOps.StateVector;
fsi: CARDINALLOOPHOLE[frame-1, POINTER TO CARDINAL]^;
size: CARDINAL;
IF fsi >= PrincOps.LargeReturnSlot
THEN BEGIN
size ← LOOPHOLE[frame-2, POINTER TO CARDINAL]^;
FOR i: PrincOps.FrameSizeIndex IN PrincOps.FrameSizeIndex
DO IF size <= PrincOps.FrameVec[i] THEN { newFrame ← PrincOpsUtils.Alloc[fsi ← i]; EXIT };
REPEAT FINISHED => ERROR
ENDLOOP;
END
ELSE { size ← PrincOps.FrameVec[fsi]; newFrame ← PrincOpsUtils.Alloc[fsi] };
PrincOpsUtils.LongCOPY[from: frame, to: newFrame, nwords: PrincOps.FrameVec[fsi]];
newFrame.returnlink.frame ← PrincOpsUtils.MyLocalFrame[];
IF style = ME
THEN LOOPHOLE[newFrame, PROC[BOOL]][FALSE]
ELSE LOOPHOLE[newFrame, PROC][];
state ← STATE;
SELECT TRUE FROM
(style = ME AND state.stkptr = 1) =>
queue ← LOOPHOLE[state.stk[0],POINTER];
(style = MRE AND state.stkptr = 2) =>
queue ← LOOPHOLE[state.stk[1],POINTER];
(style = ME AND state.stkptr = 2) =>
queue
LOOPHOLE[Basics.LongNumber[num[lowbits: state.stk[0], highbits: state.stk[1]]]];
(style = MRE AND state.stkptr = 4) =>
queue
LOOPHOLE[Basics.LongNumber[num[lowbits: state.stk[2], highbits: state.stk[3]]]];
ENDCASE => ERROR;
-- Beware if the queue should be in the victim's local frame! --
BEGIN
queueCard: LONG CARDINAL = LOOPHOLE[queue];
frameBase: LONG CARDINAL = LOOPHOLE[LONG[newFrame]];
IF queueCard > frameBase AND queueCard <= frameBase + size
THEN queue ← queue - frameBase + LOOPHOLE[LONG[frame],LONG CARDINAL];
END;
END;
-- remove the tangle trap --
IF WVMPrivate.Patch[world: world, addr: LOOPHOLE[wordAddr, WorldVM.Address],
offset: offset, byte: op] # trap
THEN ERROR;
-- Transfer the process to the ready list if it's still on the queue --
BEGIN
handle: PrincOps.PsbHandle = PrincOpsUtils.PsbIndexToHandle[psbi];
queuePage: PrincOps.PageNumber =
LOOPHOLE[queue, LONG CARDINAL] / PrincOps.wordsPerPage;
THROUGH [1..50] -- garbage check --
DO [] ← queue^; -- queue may be non-resident --
PrincOpsUtils.DisableInterrupts[];
IF BootFileChanges.IsVacant[queuePage] THEN EXIT;
PrincOpsUtils.EnableInterrupts[];
REPEAT FINISHED => ERROR
ENDLOOP;
-- now disabled, with queue swapped in --
IF OnQueue[world, psbi, queue]
THEN PrincOpsUtils.EnableAndRequeue[queue, @PrincOps.PDA.ready, handle]
ELSE PrincOpsUtils.EnableInterrupts[];
END;
END--Dequeue--;
AbortFrame: PROC RETURNS[ POINTER TO local PrincOps.Frame ] =
BEGIN
state: RECORD[a, b: UNSPECIFIED, v: PrincOps.StateVector];
psbi: PSBI;
Caller: PROC[PrincOps.FrameHandle] = LOOPHOLE[PrincOpsUtils.GetReturnFrame[]];
Caller[PrincOpsUtils.MyLocalFrame[]];
-- execution resumes in the victim process --
state.v ← STATE;
psbi ← PrincOpsUtils.PsbHandleToIndex[PrincOpsUtils.ReadPSB[]];
Wait[psbi];
-- now the initiating process has finished with the victim's frames --
IF PrincOps.PDA.block[psbi].flags.abort
THEN BEGIN
-- now read trapee's op-code, to distinguish ME from MRE --
caller: PrincOps.FrameHandle = PrincOpsUtils.GetReturnFrame[];
code: LONG POINTER = caller.accesslink.code.longbase;
pc: PrincOps.BytePC = [caller.pc-1];
wordAddr: LONG POINTER = code + pc / 2;
offset: [0..1] = pc MOD 2;
word: PrincOps.InstWord = wordAddr^;
op: PrincOps.op = IF offset = 0 THEN word.evenbyte ELSE word.oddbyte;
-- In the ME case, we handle aborted; otherwise MRE handles it --
IF op = PrincOps.zME OR op = zTrapME
THEN { PrincOps.PDA.block[psbi].flags.abort ← FALSE; ERROR ABORTED };
END;
state.v.dest.frame ← PrincOpsUtils.GetReturnFrame[];
state.v.source ← PrincOps.NullLink;
RETURN WITH state.v;
END;
TrapME: PROC =
BEGIN
state: RECORD[a, b: UNSPECIFIED, v: PrincOps.StateVector];
state.v ← STATE;
state.v.instbyte ← PrincOps.zME;
Trap[@state.v];
RETURN WITH state.v;
END;
TrapMRE: PROC =
BEGIN
state: RECORD[a, b: UNSPECIFIED, v: PrincOps.StateVector];
state.v ← STATE;
state.v.instbyte ← PrincOps.zMRE;
Trap[@state.v];
RETURN WITH state.v
END;
Trap: PROC[v: PrincOps.SVPointer] = INLINE
-- MUST be INLINE, since it assumes it's in the trap handler's local frame --
BEGIN
trapee: PrincOps.FrameHandle = PrincOpsUtils.GetReturnFrame[];
IF trapee.returnlink.frame.accesslink = PrincOpsUtils.MyGlobalFrame[]
THEN BEGIN
v.instbyte ← 0;
v.dest ← trapee.returnlink;
PrincOpsUtils.Free[trapee];
END
ELSE v.dest.frame ← trapee;
END;
OpcodeLengths: PACKED ARRAY [0..255] OF [0..3] = [ -- copied from Traps.mesa
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1,
2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1,
1, 1, 1, 1, 2, 3, 2, 2, 2, 3, 0, 0, 0, 1, 1, 1, 1, 1, 2, 1, 1, 1, 2, 3, 3,
2, 1, 2, 1, 2, 2, 2, 2, 2, 2, 2, 1, 1, 2, 3, 2, 3, 1, 1, 2, 2, 2, 2, 2, 2,
2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 1, 1, 1, 2, 2, 1, 1, 1, 2, 1, 1, 1, 1, 0, 0,
0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 2, 3, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1,
1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2,
1, 1, 2, 1, 1, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 1, 1, 1, 2, 2, 2,
0, 2, 2, 1, 0];
******** Part 2: Freezing and process information ********
qFreeze: PrincOps.FaultIndex = 3;
freezeQueue: LONG POINTER TO PrincOps.Queue = @PrincOps.PDA.fault[qFreeze].queue;
GFTable: TYPE = AMProcessBasic.GFTable;
--AMProcessBasic.--Info: PUBLIC PROC[world: WorldVM.World,
psbi: PSBI,
freeze: BOOL, -- freeze at boundary of filter
thaw: BOOL, -- unfreeze if not in filter
fullStatus: BOOL, -- whether to distinguish fault and ready queues --
filter: GFTable, -- interesting global frames --
wantedStates: PACKED ARRAY AMProcessBasic.State OF BOOL -- interesting states --]
RETURNS[
state: AMProcessBasic.State ← dead,
faultData: LONG CARDINAL ← 0,
priority: PrincOps.Priority ← 0,
frame: PrincOps.FrameHandle ← NIL,
frozenFrame: PrincOps.FrameHandle ← NIL,
topFrame: PrincOps.FrameHandle ← NIL -- current frame of process --] =
BEGIN
Delicate!
If process is dead, returns [dead, 0, NIL]
Returns state, but if not "fullStatus" treats fault and ready queues as "unknown".
If "fullStatus", returns "faultData" from fault state vector, if any.
Returns "frame" as first frame in stack scan that's inside the filter (or first, if filter=NIL);
If no such frame, then frame ← NIL.
If "freeze", freezes process at "frame", unless earlier frame in stack scan is already frozen;
If "freeze" and "thaw", freezes process at "frame", then thaws any earlier frozen frame.
frozen: BOOL;
processFrame, prevFrame, freezeTrap: PrincOps.FrameHandle;
restOfStack: PrincOps.ControlLink;
LockFilter[filter];
-- lock out anyone else from modifying victim process --
Set[psbi];
restOfStack ← GetFreezee[world, psbi];
freezeTrap ← Freezer[world];
[priority, frozen, state, processFrame, faultData] ← InfoFromPSB[world, psbi, fullStatus];
IF state = dead THEN RETURN;
-- now, world and psbi are locked --
IF NOT wantedStates[state] THEN { Unlock[world]; Clear[psbi]; UnlockFilter[filter]; RETURN};
[frame, prevFrame] ← ApplyFilter[world, [frame[processFrame]], filter, [frame[freezeTrap]] !
UNWIND => { Unlock[world]; Clear[psbi]; UnlockFilter[filter] } ];
frozenFrame ← IF restOfStack = PrincOps.NullLink
THEN NIL
ELSE IF frozen
THEN GetLink[world, restOfStack.frame].frame
ELSE restOfStack.frame;
topFrame ← SELECT TRUE FROM
frozen, freezeTrap=processFrame => frozenFrame,
ENDCASE => processFrame;
SELECT TRUE FROM
frame # freezeTrap AND frame # NIL =>
BEGIN
A victim frame was found, and it's in unfrozen territory.
IF freeze
THEN BEGIN
-- freeze here --
IF frame = processFrame
THEN SetPsbFrame[world, psbi, freezeTrap]
ELSE SetLink[world, prevFrame, [frame[freezeTrap]]];
Unlock[world];
IF restOfStack # PrincOps.NullLink
THEN BEGIN
tail: PrincOps.FrameHandle ← frame;
DO next: PrincOps.FrameHandle = GetLink[world, tail].frame;
IF next = freezeTrap THEN EXIT;
tail ← next;
ENDLOOP;
SetLink[world, tail, restOfStack];
END;
SetFreezee[world, psbi, [frame[frame]]];
frozenFrame ← frame;
END
ELSE Unlock[world];
END;
frame = freezeTrap =>
BEGIN
If there is a victim, it must be inside the frozen territory.
[frame, prevFrame] ← ApplyFilter[world, restOfStack, filter, PrincOps.NullLink !
UNWIND => { Unlock[world]; Clear[psbi]; UnlockFilter[filter] } ];
IF frame # NIL
AND frame # restOfStack.frame
AND (NOT frozen OR frame # frozenFrame)
AND freeze AND thaw
THEN BEGIN
A victim was found, and we must contract the frozen territory.
SetLink[world, prevFrame, [frame[freezeTrap]]];
Unfreeze[world, psbi, processFrame, restOfStack];
SetFreezee[world, psbi, [frame[frame]]];
frozenFrame ← frame;
END
ELSE Unlock[world];
END;
ENDCASE => Unlock[world];
-- clean up --
Clear[psbi];
UnlockFilter[filter]
END--Info--;
Thaw: PUBLIC PROC[world: WorldVM.World, psbi: PrincOps.PsbIndex] =
BEGIN
processFrame: PrincOps.FrameHandle;
restOfStack: PrincOps.ControlLink;
Set[psbi];
restOfStack ← GetFreezee[world, psbi];
IF restOfStack # PrincOps.NullLink
THEN BEGIN
processFrame ← InfoFromPSB[world, psbi, FALSE].processFrame; -- locks world --
Unfreeze[world, psbi, processFrame, restOfStack]; -- unlocks world --
END;
Clear[psbi];
END;
Unfreeze: PROC[world: WorldVM.World, psbi: PrincOps.PsbIndex,
processFrame: PrincOps.FrameHandle,
restOfStack: PrincOps.ControlLink] =
BEGIN
-- On entry process and world are locked. On exit, only process is locked. --
freezeTrap: PrincOps.FrameHandle = Freezer[world];
IF processFrame = freezeTrap
THEN BEGIN
SetPsbFrame[world, psbi, restOfStack.frame];
[] ← OnQueue[world, psbi, freezeQueue, TRUE];
END
ELSE BEGIN
tail: PrincOps.FrameHandle ← processFrame;
DO next: PrincOps.FrameHandle = GetLink[world, tail].frame;
IF next = freezeTrap THEN EXIT;
tail ← next;
ENDLOOP;
SetLink[world, tail, restOfStack];
END;
Unlock[world];
SetFreezee[world, psbi, PrincOps.NullLink];
END;
LockFilter: PROC[filter: GFTable] =
BEGIN
IF filter # NIL
THEN BEGIN
base: VM.PageNumber = VM.PageNumberForAddress[LOOPHOLE[filter]];
top: VM.PageNumber = VM.PageNumberForAddress[
LOOPHOLE[filter,LONG POINTER] + SIZE[AMProcessBasic.GFTableObject[filter.length]]-1
];
VM.Pin[[page: base, count: top-base+1]];
END;
END;
UnlockFilter: PROC[filter: GFTable] =
BEGIN
IF filter # NIL
THEN BEGIN
base: VM.PageNumber = VM.PageNumberForAddress[LOOPHOLE[filter]];
top: VM.PageNumber = VM.PageNumberForAddress[
LOOPHOLE[filter,LONG POINTER] + SIZE[AMProcessBasic.GFTableObject[filter.length]]-1
];
VM.Unpin[[page: base, count: top-base+1]];
END;
END;
ApplyFilter: PROC[world: WorldVM.World,
link: PrincOps.ControlLink,
filter: GFTable,
stopAt: PrincOps.ControlLink ]
RETURNS[ frame, prevFrame: PrincOps.FrameHandle] = INLINE
BEGIN
-- "filter" is resident; world is locked. --
"frame" ← the first frame whose global frame inside the filter (or NIL if no such frame).
If "frame" is not NIL and not "processFrame", prevFrame ← frame with returnlink "frame".
frame ← link.frame;
IF filter = NIL THEN RETURN;
IF world = local
THEN DO
IF stopAt = [frame[frame]] THEN EXIT;
IF AddrBad[frame] OR AddrBad[frame.accesslink] THEN { frame ← NIL; EXIT };
FOR i: CARDINAL IN [0..filter.count)
DO IF frame.accesslink = filter[i] THEN GOTO found ENDLOOP;
IF frame.returnlink = PrincOps.NullLink OR frame.returnlink.proc
THEN { frame ← NIL; EXIT };
prevFrame ← frame; frame ← frame.returnlink.frame;
REPEAT
found => NULL
ENDLOOP
ELSE [frame, prevFrame] ← ApplyRemoteFilter[world, link, filter, stopAt]
END;
ApplyRemoteFilter: PROC[world: WorldVM.World,
link: PrincOps.ControlLink,
filter: GFTable,
stopAt: PrincOps.ControlLink ]
RETURNS[ frame, prevFrame: PrincOps.FrameHandle] =
BEGIN
frame ← link.frame;
DO ENABLE WorldVM.AddressFault => { frame ← NIL; EXIT };
fHeader: PrincOps.Frame;
IF stopAt = [frame[frame]] THEN EXIT;
WorldVM.CopyRead[world: world,
from: WorldVM.Long[world, LOOPHOLE[frame] ],
to: @fHeader, nwords: SIZE[PrincOps.Frame] ];
FOR i: CARDINAL IN [0..filter.count)
DO IF fHeader.accesslink = filter[i] THEN GOTO found ENDLOOP;
IF fHeader.returnlink = PrincOps.NullLink OR fHeader.returnlink.proc
THEN { frame ← NIL; EXIT };
prevFrame ← frame; frame ← fHeader.returnlink.frame;
REPEAT
found => NULL
ENDLOOP;
END;
ReturnLink: PUBLIC PROC[world: WorldVM.World, frame: PrincOps.FrameHandle,
psbi: PrincOps.PsbIndex ← PrincOps.PsbNull]
RETURNS[link: PrincOps.ControlLink] =
-- This returns the "virtual" return link: the one that would be there if the process was not frozen. --
BEGIN
freezer: POINTER TO local PrincOps.Frame = Freezer[world];
link ← GetLink[world, frame];
IF link # [frame[freezer]] THEN RETURN;
IF psbi # PrincOps.PsbNull
THEN { Set[psbi]; link ← GetFreezee[world, psbi] }
ELSE FOR psbi IN PrincOps.PsbIndex
DO Set[psbi];
IF (link ← GetFreezee[world, psbi]) # PrincOps.NullLink
THEN BEGIN
state: AMProcessBasic.State;
processFrame: PrincOps.FrameHandle;
[state: state, processFrame: processFrame] ← InfoFromPSB[world, psbi, FALSE];
IF state # dead
THEN BEGIN
ENABLE UNWIND => Clear[psbi];
other: PrincOps.ControlLink ← [frame[processFrame]];
Unlock[world];
UNTIL other = [frame[freezer]] OR other.indirect OR other.proc
DO IF other.frame = frame THEN GOTO found;
other ← GetLink[world, frame];
ENDLOOP;
END;
END;
Clear[psbi];
REPEAT
found => NULL;
FINISHED => ERROR
ENDLOOP;
Clear[psbi];
END;
freezerAddr: POINTER TO POINTER TO local PrincOps.Frame =
LOOPHOLE[@(PrincOps.SD[205B])];
freezeesAddr: POINTER TO LONG POINTER TO DebuggerSwap.Frozen =
LOOPHOLE[@(PrincOps.SD[206B])];
GetFreezee: PROC[world: WorldVM.World, psbi: PSBI] RETURNS[PrincOps.ControlLink] =
{ RETURN[ IF world = local
THEN DebuggerSwap.freezeesTable[psbi]
ELSE LOOPHOLE[WorldVM.Read[world, Freezees[world] + psbi]] ] };
SetFreezee: PROC[world: WorldVM.World, psbi: PSBI, freezee: PrincOps.ControlLink] =
{ WorldVM.Write[world, Freezees[world] + psbi, LOOPHOLE[freezee] ] };
Freezees: PROC[world: WorldVM.World] RETURNS[ WorldVM.Address ] =
{ RETURN[ LOOPHOLE[WorldVM.LongRead[world,
WorldVM.Long[world, LOOPHOLE[freezeesAddr]]]] ] };
Freezer: PROC[world: WorldVM.World] RETURNS[POINTER TO local PrincOps.Frame] =
{ RETURN[ IF world = local
THEN DebuggerSwap.freezer
ELSE LOOPHOLE[WorldVM.Read[world, WorldVM.Long[world, LOOPHOLE[freezerAddr]]]] ] };
******** Part 3: common subroutines ********
GetLink: PROC[world: WorldVM.World, frame: PrincOps.FrameHandle]
RETURNS[PrincOps.ControlLink] = INLINE
{ RETURN[IF world = local THEN frame.returnlink ELSE GetRemoteLink[world, frame] ] };
GetRemoteLink: PROC[world: WorldVM.World, frame: PrincOps.FrameHandle]
RETURNS[PrincOps.ControlLink] =
BEGIN
fHeader: PrincOps.Frame;
WorldVM.CopyRead[world: world,
from: WorldVM.Long[world, LOOPHOLE[frame] ],
to: @fHeader,
nwords: SIZE[PrincOps.Frame] ];
RETURN[fHeader.returnlink]
END;
SetLink: PROC[world: WorldVM.World, frame: PrincOps.FrameHandle,
link: PrincOps.ControlLink] = INLINE
{ IF world = local THEN frame.returnlink ← link ELSE SetRemoteLink[world, frame, link] };
SetRemoteLink: PROC[world: WorldVM.World, frame: PrincOps.FrameHandle,
link: PrincOps.ControlLink] =
BEGIN
fHeader: PrincOps.Frame;
WorldVM.CopyRead[world: world,
from: WorldVM.Long[world, LOOPHOLE[frame] ],
to: @fHeader,
nwords: SIZE[PrincOps.Frame] ];
fHeader.returnlink ← link;
WorldVM.CopyWrite[world: world,
from: @fHeader,
to: WorldVM.Long[world, LOOPHOLE[frame] ],
nwords: SIZE[PrincOps.Frame] ];
END;
SetPsbFrame: PROC[world: WorldVM.World, psbi: PSBI,
trapFrame: PrincOps.FrameHandle] = INLINE
BEGIN
on entry and exit, world and psbi are locked.
IF world = local
THEN BEGIN
IF PrincOps.PDA.block[psbi].link.vector
THEN PrincOps.PDA[PrincOps.PDA.block[psbi].context.state].frame ← LOOPHOLE[trapFrame]
ELSE PrincOps.PDA.block[psbi].context.frame ← trapFrame;
END
ELSE SetRemotePsbFrame[world, psbi, trapFrame];
END;
SetRemotePsbFrame: PROC[world: WorldVM.World, psbi: PSBI,
trapFrame: PrincOps.FrameHandle] =
BEGIN
on entry and exit, world and psbi are locked.
psb: PrincOps.ProcessStateBlock ← GetPSB[psbi, world];
IF psb.link.vector
THEN BEGIN
stateAddr: WorldVM.Address =
LOOPHOLE[PrincOps.PDA, WorldVM.Address] + LOOPHOLE[psb.context.state, CARDINAL];
state: PrincOps.StateVector;
WorldVM.CopyRead[world: world, from: stateAddr, to: @state,
nwords: SIZE[PrincOps.StateVector] ];
state.frame ← LOOPHOLE[trapFrame];
WorldVM.CopyWrite[world: world, from: @state, to: stateAddr,
nwords: SIZE[PrincOps.StateVector] ];
END
ELSE BEGIN
psb.context.frame ← trapFrame;
WorldVM.CopyWrite[world: world, from: @psb, to: PsbAddr[world, psbi],
nwords: SIZE[PrincOps.ProcessStateBlock] ];
END;
END;
InfoFromPSB: PROC[world: WorldVM.World, psbi: PSBI, fullStatus: BOOL] RETURNS[
priority: PrincOps.Priority,
frozen: BOOL,
state: AMProcessBasic.State,
processFrame: PrincOps.FrameHandle,
faultData: LONG CARDINAL ← 0 ] =
BEGIN
psb: PrincOps.ProcessStateBlock;
-- prevent victim from proceeding --
Lock[world]; -- Also disables interrupts and stops processor timeout scan if world = local --
BEGIN
ENABLE UNWIND => { Unlock[world]; Clear[psbi] };
psb ← GetPSB[psbi, world];
priority ← psb.link.priority;
-- get status --
IF psb.flags.processState.state = dead
THEN { Unlock[world]; Clear[psbi]; state ← dead; RETURN };
frozen ← OnQueue[world, psbi, freezeQueue];
SELECT TRUE FROM
psb.flags.waiting => state ← waitingCV;
fullStatus => state ← GetQueueState[psbi, world, psb.link.failed];
ENDCASE => state ← unknown;
-- get context --
IF psb.link.vector
THEN BEGIN
sv: PrincOps.StateVector;
stateAddr: WorldVM.Address =
LOOPHOLE[PrincOps.PDA, WorldVM.Address] + LOOPHOLE[psb.context.state, CARDINAL];
IF world = local -- avoid making a procedure call to non-resident code! --
THEN PrincOpsUtils.LongCOPY[from: LOOPHOLE[stateAddr],
to: @sv,
nwords: SIZE[PrincOps.StateVector] ]
ELSE WorldVM.CopyRead[world: world,
from: stateAddr,
to: @sv,
nwords: SIZE[PrincOps.StateVector] ];
processFrame ← sv.frame;
faultData ← SELECT state FROM
frameFault => sv.fsi,
pageFault, writeProtectFault => LOOPHOLE[sv.memPointer],
IN AMProcessBasic.Faulted =>
LOOPHOLE[@sv.dataArray, POINTER TO LONG CARDINAL]^
ENDCASE => 0;
END
ELSE processFrame ← psb.context.frame;
END--UNWIND catch--;
END;
GetQueueState: PROC[psbi: CARDINAL, world: WorldVM.World, enterFailed: BOOL]
RETURNS[state: AMProcessBasic.State] = INLINE
BEGIN
IF OnQueue[world, psbi, @PrincOps.PDA.ready] THEN RETURN[ready];
FOR q: PrincOps.FaultIndex IN PrincOps.FaultIndex
DO IF OnQueue[world, psbi, @(PrincOps.PDA.fault[q].queue)]
THEN SELECT q FROM
PrincOps.qFrameFault => RETURN[frameFault];
PrincOps.qPageFault,
PrincOps.qPageFault+4 => RETURN[pageFault]; -- "+4" for software queues
PrincOps.qWriteProtectFault,
PrincOps.qWriteProtectFault+4 => RETURN[writeProtectFault];
qFreeze => RETURN[ready];
ENDCASE => RETURN[unknownFault];
ENDLOOP;
RETURN[IF enterFailed THEN waitingML ELSE unknown]
END;
OnQueue: PROC[world: WorldVM.World, psbi: PSBI, queueHandle: PrincOps.QueueHandle,
remove: BOOLFALSE]
RETURNS[BOOL] = INLINE
BEGIN
IF world = local
THEN BEGIN
tail, prev: PSBI;
IF queueHandle^ = PrincOps.QueueEmpty THEN RETURN[FALSE];
prev ← tail ← queueHandle.tail;
THROUGH [FIRST[PSBI]..LAST[PSBI]+1] -- garbage protection --
DO next: PSBI = PrincOps.PDA.block[prev].link.next;
IF next = psbi
THEN BEGIN
IF remove
THEN PrincOpsUtils.Requeue[queueHandle, @PrincOps.PDA.ready,
PrincOpsUtils.PsbIndexToHandle[psbi]];
RETURN[TRUE]
END;
prev ← next;
IF prev = tail THEN RETURN[FALSE];
ENDLOOP;
RETURN[FALSE] -- actually, the queue is thoroughly mangled! --
END
ELSE RETURN[ OnRemoteQueue[world, psbi, LOOPHOLE[queueHandle], remove] ];
END;
OnRemoteQueue: PROC[world: WorldVM.World, psbi: PSBI, queueHandle: WorldVM.Address,
remove: BOOL]
RETURNS[BOOL] =
BEGIN
dest: LONG POINTER TO PrincOps.Queue = IF remove THEN @PrincOps.PDA.ready ELSE NIL;
queue: PrincOps.Queue;
tail, prev: PSBI;
WorldVM.CopyRead[world: world, from: LOOPHOLE[queueHandle, WorldVM.Address],
to: @queue, nwords: SIZE[PrincOps.Queue]];
IF queue = PrincOps.QueueEmpty THEN RETURN[FALSE];
prev ← tail ← queue.tail;
THROUGH [FIRST[PSBI]..LAST[PSBI]+1] -- garbage protection --
DO psb: PrincOps.ProcessStateBlock ← GetPSB[prev, world];
IF psb.link.next = psbi
THEN BEGIN
IF dest # NIL
THEN BEGIN
this: PrincOps.ProcessStateBlock ← GetPSB[psbi, world];
newQueue: PrincOps.Queue;
WorldVM.CopyRead[world: world,
from: LOOPHOLE[dest, WorldVM.Address],
to: @newQueue, nwords: SIZE[PrincOps.Queue]];
-- dequeue --
psb.link.next ← this.link.next;
IF queue.tail = psbi
THEN queue.tail ← IF prev = psbi THEN PrincOps.PsbNull ELSE prev;
-- enqueue --
IF newQueue.tail = PrincOps.PsbNull
THEN this.link.next ← newQueue.tail ← psbi
ELSE BEGIN
-- scan queue for correct priority position --
tempPSBI: PSBI ← newQueue.tail;
temp: PrincOps.ProcessStateBlock ← GetPSB[tempPSBI, world];
IF temp.link.priority >= this.link.priority
THEN newQueue.tail ← psbi
ELSE -- search until we find the correct priority --
DO next: PrincOps.ProcessStateBlock ← GetPSB[temp.link.next, world];
IF this.link.priority > next.link.priority THEN EXIT;
tempPSBI ← temp.link.next; temp ← next;
ENDLOOP;
this.link.next ← temp.link.next;
temp.link.next ← psbi;
WorldVM.CopyWrite[world: world, from: @temp, to: PsbAddr[world, tempPSBI],
nwords: SIZE[PrincOps.ProcessStateBlock]];
END;
-- copy back --
WorldVM.CopyWrite[world: world, from: @psb, to: PsbAddr[world, prev],
nwords: SIZE[PrincOps.ProcessStateBlock]];
WorldVM.CopyWrite[world: world, from: @this, to: PsbAddr[world, psbi],
nwords: SIZE[PrincOps.ProcessStateBlock]];
WorldVM.CopyWrite[world: world, from: @queue,
to: LOOPHOLE[queueHandle, WorldVM.Address],
nwords: SIZE[PrincOps.Queue]];
WorldVM.CopyWrite[world: world, from: @newQueue,
to: LOOPHOLE[dest, WorldVM.Address],
nwords: SIZE[PrincOps.Queue]];
END;
RETURN[TRUE]
END;
prev ← psb.link.next;
IF prev = tail THEN RETURN[FALSE];
ENDLOOP;
RETURN[FALSE] -- actually, the queue is thoroughly mangled! --
END;
GetPSB: PROC[psbi: PSBI, world: WorldVM.World, abort: BOOLFALSE]
RETURNS[PrincOps.ProcessStateBlock] = INLINE
BEGIN
IF world = local
THEN BEGIN
IF abort THEN PrincOps.PDA.block[psbi].flags.abort ← TRUE;
RETURN[ PrincOps.PDA.block[psbi] ]
END
ELSE RETURN[ GetRemotePSB[psbi, world, abort] ]
END;
GetRemotePSB: PROC[psbi: PSBI, world: WorldVM.World, abort: BOOL]
RETURNS[psb: PrincOps.ProcessStateBlock] =
BEGIN
psbAddr: WorldVM.Address = PsbAddr[world, psbi];
WorldVM.CopyRead[world: world,
from: psbAddr,
to: @psb,
nwords: SIZE[PrincOps.ProcessStateBlock]];
IF abort
THEN BEGIN
psb.flags.abort ← TRUE;
WorldVM.CopyWrite[world: world,
from: @psb,
to: psbAddr,
nwords: SIZE[PrincOps.ProcessStateBlock]];
END;
END;
PsbAddr: PROC[world: WorldVM.World, psbi: PSBI] RETURNS[ WorldVM.Address ] =
{ RETURN[ LOOPHOLE[PrincOps.PDA, WorldVM.Address] + psbi*SIZE[PrincOps.ProcessStateBlock] ] };
-- Synchronisation --
untangling: REF PACKED ARRAY PSBI OF BOOL =
NEW[PACKED ARRAY PSBI OF BOOLALL[FALSE] ];
finishedUntangling: CONDITION ← [timeout:0];
Set: ENTRY PROC[psbi: PSBI] =
{ WHILE untangling[psbi] DO WAIT finishedUntangling ENDLOOP; untangling[psbi] ← TRUE };
Wait: ENTRY PROC[psbi: PSBI] = INLINE
{ WHILE untangling[psbi] DO WAIT finishedUntangling ENDLOOP };
Clear: ENTRY PROC[psbi: PSBI] =
{ untangling[psbi] ← FALSE; BROADCAST finishedUntangling };
-- Access to client memory with client stopped --
local: WorldVM.World = WorldVM.LocalWorld[];
Lock: PROC[world: WorldVM.World] =
{ IF world = local
THEN PrincOpsUtils.DisableInterrupts[]
ELSE WorldVM.Lock[world] };
Unlock: PROC[world: WorldVM.World] = INLINE
{ IF world = local
THEN PrincOpsUtils.EnableInterrupts[]
ELSE WorldVM.Unlock[world] };
AddrBad: PROC[addr: LONG POINTER] RETURNS[BOOL] = INLINE
{ OPEN a: LOOPHOLE[addr, num Basics.LongNumber];
IF a.highbits >= 256 THEN RETURN[TRUE];
RETURN[ BootFileChanges.IsVacant[a.highbits*256 + a.lowbits/256]] };
Loader.MakeProcedureResident[Info];
Loader.MakeProcedureResident[Dequeue];
TrapSupport.opTrapTable.main[zTrapME] ← LOOPHOLE[TrapME];
TrapSupport.opTrapTable.main[zTrapMRE] ← LOOPHOLE[TrapMRE];
END.