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Some cleanup involving invalid addresses

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This commit is contained in:
Jeff Parsons 2014-12-01 13:31:23 -08:00 • committed by jeffpar
commit c85398db6b
7 changed files with 124 additions and 82 deletions
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112
modules/pcjs/lib/x86seg.js
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@ -57,7 +57,7 @@ function X86Seg(cpu, id, sName, fProt)
this.base = 0;
this.limit = 0xffff;
this.acc = 0;
this.addrDesc = null;
this.addrDesc = X86.ADDR_INVALID;
this.cpl = 0;
this.dpl = 0;
/*
@ -76,11 +76,12 @@ function X86Seg(cpu, id, sName, fProt)
* to a numerically lower privilege, and fCall == false allows a stack switch (restore) and a privilege
* transition to a numerically greater privilege.
*
* As long as setCSIP() is used for all CS changes, the foregoing is automatically taken care of.
* As long as setCSIP() or opHelpINT() are used for all CS changes, the foregoing is automatically
* taken care of.
*
* TODO: Consider making fCall a parameter to load(), instead of a property that must be set prior to
* calling load(); the downside (and why I didn't do that in the first place) is that such a parameter
* to load() would be meaningless for segments other than segCS.
* is meaningless for segments other than segCS.
*/
this.awScratch = (this.id == X86Seg.ID.CODE? new Array(32) : []);
this.fCall = null;
@ -111,7 +112,7 @@ X86Seg.ID = {
* @this {X86Seg}
* @param {number} sel
* @param {boolean} [fSuppress] is true to suppress any errors
* @return {number|null} base address of selected segment, or null if error
* @return {number} base address of selected segment, or ADDR_INVALID if error (TODO: No error conditions exist yet)
*/
X86Seg.loadReal = function loadReal(sel, fSuppress)
{
@ -140,7 +141,7 @@ X86Seg.loadReal = function loadReal(sel, fSuppress)
* @this {X86Seg}
* @param {number} sel
* @param {boolean} [fSuppress] is true to suppress any errors, cycle assessment, etc
* @return {number|null} base address of selected segment, or null if error
* @return {number} base address of selected segment, or ADDR_INVALID if error
*/
X86Seg.loadProt = function loadProt(sel, fSuppress)
{
@ -180,7 +181,7 @@ X86Seg.loadProt = function loadProt(sel, fSuppress)
X86Help.opHelpFault.call(cpu, X86.EXCEPTION.GP_FAULT, sel);
}
}
return null;
return X86.ADDR_INVALID;
};
/**
@ -188,7 +189,7 @@ X86Seg.loadProt = function loadProt(sel, fSuppress)
*
* @this {X86Seg}
* @param {number} nIDT
* @return {number|null} base address of selected segment, or null if error
* @return {number} base address of selected segment, or ADDR_INVALID if error (TODO: No error conditions exist yet)
*/
X86Seg.loadRealIDT = function loadRealIDT(nIDT)
{
@ -213,7 +214,7 @@ X86Seg.loadRealIDT = function loadRealIDT(nIDT)
*
* @this {X86Seg}
* @param {number} nIDT
* @return {number|null} base address of selected segment, or null if error
* @return {number} base address of selected segment, or ADDR_INVALID if error (TODO: No error conditions exist yet)
*/
X86Seg.loadProtIDT = function loadProtIDT(nIDT)
{
@ -226,7 +227,7 @@ X86Seg.loadProtIDT = function loadProtIDT(nIDT)
return this.loadDesc8(addrDesc, nIDT);
}
X86Help.opHelpFault.call(cpu, X86.EXCEPTION.GP_FAULT, nIDT | X86.ERRCODE.IDT | X86.ERRCODE.EXT, true);
return null;
return X86.ADDR_INVALID;
};
/**
@ -239,7 +240,7 @@ X86Seg.loadProtIDT = function loadProtIDT(nIDT)
* @param {number} off is a segment-relative offset
* @param {number} cb is number of extra bytes to check (0 or 1)
* @param {boolean} [fSuppress] is true to suppress any errors
* @return {number|null} corresponding physical address if valid, null if not
* @return {number} corresponding physical address if valid, or ADDR_INVALID if error (TODO: No error conditions exist yet)
*/
X86Seg.checkReadReal = function checkReadReal(off, cb, fSuppress)
{
@ -256,7 +257,7 @@ X86Seg.checkReadReal = function checkReadReal(off, cb, fSuppress)
* @param {number} off is a segment-relative offset
* @param {number} cb is number of extra bytes to check (0 or 1)
* @param {boolean} [fSuppress] is true to suppress any errors
* @return {number|null} corresponding physical address if valid, null if not
* @return {number} corresponding physical address if valid, or ADDR_INVALID if error (TODO: No error conditions exist yet)
*/
X86Seg.checkWriteReal = function checkWriteReal(off, cb, fSuppress)
{
@ -270,7 +271,7 @@ X86Seg.checkWriteReal = function checkWriteReal(off, cb, fSuppress)
* @param {number} off is a segment-relative offset
* @param {number} cb is number of extra bytes to check (0 or 1)
* @param {boolean} [fSuppress] is true to suppress any errors
* @return {number|null} corresponding physical address if valid, null if not
* @return {number} corresponding physical address if valid, or ADDR_INVALID if not
*/
X86Seg.checkReadProt = function checkReadProt(off, cb, fSuppress)
{
@ -287,7 +288,7 @@ X86Seg.checkReadProt = function checkReadProt(off, cb, fSuppress)
* @param {number} off is a segment-relative offset
* @param {number} cb is number of extra bytes to check (0 or 1)
* @param {boolean} [fSuppress] is true to suppress any errors
* @return {number|null} corresponding physical address if valid, null if not
* @return {number} corresponding physical address if valid, ADDR_INVALID if not
*/
X86Seg.checkReadProtDown = function checkReadProtDown(off, cb, fSuppress)
{
@ -304,14 +305,14 @@ X86Seg.checkReadProtDown = function checkReadProtDown(off, cb, fSuppress)
* @param {number} off is a segment-relative offset
* @param {number} cb is number of extra bytes to check (0 or 1)
* @param {boolean} [fSuppress] is true to suppress any errors
* @return {number|null} corresponding physical address if valid, null if not
* @return {number} corresponding physical address if valid, ADDR_INVALID if not
*/
X86Seg.checkReadProtDisallowed = function checkReadProtDisallowed(off, cb, fSuppress)
{
if (!fSuppress) {
X86Help.opHelpFault.call(this.cpu, X86.EXCEPTION.GP_FAULT, 0);
}
return null;
return X86.ADDR_INVALID;
};
/**
@ -321,7 +322,7 @@ X86Seg.checkReadProtDisallowed = function checkReadProtDisallowed(off, cb, fSupp
* @param {number} off is a segment-relative offset
* @param {number} cb is number of extra bytes to check (0 or 1)
* @param {boolean} [fSuppress] is true to suppress any errors
* @return {number|null} corresponding physical address if valid, null if not
* @return {number} corresponding physical address if valid, ADDR_INVALID if not
*/
X86Seg.checkWriteProt = function checkWriteProt(off, cb, fSuppress)
{
@ -338,7 +339,7 @@ X86Seg.checkWriteProt = function checkWriteProt(off, cb, fSuppress)
* @param {number} off is a segment-relative offset
* @param {number} cb is number of extra bytes to check (0 or 1)
* @param {boolean} [fSuppress] is true to suppress any errors
* @return {number|null} corresponding physical address if valid, null if not
* @return {number} corresponding physical address if valid, ADDR_INVALID if not
*/
X86Seg.checkWriteProtDown = function checkWriteProtDown(off, cb, fSuppress)
{
@ -355,14 +356,14 @@ X86Seg.checkWriteProtDown = function checkWriteProtDown(off, cb, fSuppress)
* @param {number} off is a segment-relative offset
* @param {number} cb is number of extra bytes to check (0 or 1)
* @param {boolean} [fSuppress] is true to suppress any errors
* @return {number|null} corresponding physical address if valid, null if not
* @return {number} corresponding physical address if valid, ADDR_INVALID if not
*/
X86Seg.checkWriteProtDisallowed = function checkWriteProtDisallowed(off, cb, fSuppress)
{
if (!fSuppress) {
X86Help.opHelpFault.call(this.cpu, X86.EXCEPTION.GP_FAULT, 0);
}
return null;
return X86.ADDR_INVALID;
};
/**
@ -370,6 +371,20 @@ X86Seg.checkWriteProtDisallowed = function checkWriteProtDisallowed(off, cb, fSu
*
* Implements TSS (Task State Segment) task switching.
*
* NOTES: This typically occurs during double-fault processing, because the IDT entry for DF_FAULT normally
* contains a task gate. Interestingly, if we force a GP_FAULT to occur at a sufficiently early point in the
* OS/2 1.0 initialization code, OS/2 does a nice job of displaying the GP fault and then shutting down:
*
* 0090:067B FB STI
* 0090:067C EBFD JMP 067B
*
* but it may not have yet reprogrammed the master PIC to re-vector hardware interrupts to IDT entries 0x50-0x57,
* so when the next timer interrupt (IRQ 0) occurs, it vectors through IDT entry 0x08, which is the double-fault
* vector. A spurious double-fault is generated, and a clean shutdown turns into a messy crash.
*
* Of course, that all could have been avoided if IBM had heeded Intel's advice and not used Intel-reserved IDT
* entries for PC interrupts.
*
* @this {X86Seg}
* @param {number} selNew
* @param {boolean} fNest is true if nesting, false if un-nesting
@ -390,7 +405,7 @@ X86Seg.switchTSS = function switchTSS(selNew, fNest)
}
cpu.setWord(cpu.segTSS.addrDesc + X86.DESC.ACC.OFFSET, (cpu.segTSS.acc & ~X86.DESC.ACC.TYPE.TSS_BUSY) | X86.DESC.ACC.TYPE.TSS);
}
if (cpu.segTSS.load(selNew) == null) {
if (cpu.segTSS.load(selNew) == X86.ADDR_INVALID) {
return false;
}
var addrNew = cpu.segTSS.base;
@ -455,7 +470,7 @@ X86Seg.switchTSS = function switchTSS(selNew, fNest)
* @this {X86Seg}
* @param {number} sel (protected-mode only)
* @param {boolean} [fGDT] is true if sel must be in the GDT
* @return {number|null} acc field from descriptor, or null if error
* @return {number} acc field from descriptor, or X86.DESC.ACC.INVALID if error
*/
X86Seg.prototype.loadAcc = function(sel, fGDT)
{
@ -477,7 +492,7 @@ X86Seg.prototype.loadAcc = function(sel, fGDT)
}
}
X86Help.opHelpFault.call(cpu, X86.EXCEPTION.GP_FAULT, sel);
return null;
return X86.DESC.ACC.INVALID;
};
/**
@ -508,7 +523,7 @@ X86Seg.prototype.loadDesc6 = function(addrDesc, sel)
this.addrDesc = addrDesc;
this.updateMode();
this.messageDebugger(sel, base, limit, acc);
this.messageSeg(sel, base, limit, acc);
return base;
};
@ -529,7 +544,7 @@ X86Seg.prototype.loadDesc6 = function(addrDesc, sel)
* @param {number} addrDesc is the descriptor address
* @param {number} sel is the associated selector
* @param {boolean} [fSuppress] is true to suppress any errors, cycle assessment, etc
* @return {number|null} base address of selected segment, or null if error
* @return {number} base address of selected segment, or ADDR_INVALID if error
*/
X86Seg.prototype.loadDesc8 = function(addrDesc, sel, fSuppress)
{
@ -555,7 +570,7 @@ X86Seg.prototype.loadDesc8 = function(addrDesc, sel, fSuppress)
rpl = sel & X86.SEL.RPL;
if (rpl > this.cpl) {
if (fCall !== false) {
base = null;
base = X86.ADDR_INVALID;
break;
}
regSP = cpu.popWord();
@ -572,22 +587,22 @@ X86Seg.prototype.loadDesc8 = function(addrDesc, sel, fSuppress)
if (rpl < this.cpl) rpl = this.cpl;
if (rpl > dpl) {
accCode = this.loadAcc(selCode, true);
if (accCode != null && (accCode & X86.DESC.ACC.TYPE.CODE_CONFORMING) == X86.DESC.ACC.TYPE.CODE_CONFORMING) {
if (accCode != X86.DESC.ACC.INVALID && (accCode & X86.DESC.ACC.TYPE.CODE_CONFORMING) == X86.DESC.ACC.TYPE.CODE_CONFORMING) {
rpl = dpl;
}
}
if (rpl <= dpl) {
cplPrev = this.cpl;
if (this.load(selCode, true) == null) {
if (this.load(selCode, true) == X86.ADDR_INVALID) {
cpu.assert(false);
base = null;
base = X86.ADDR_INVALID;
break;
}
cpu.regIP = limit;
if (this.cpl < cplPrev) {
if (fCall !== true) {
cpu.assert(false);
base = null;
base = X86.ADDR_INVALID;
break;
}
regSP = cpu.regSP;
@ -612,28 +627,28 @@ X86Seg.prototype.loadDesc8 = function(addrDesc, sel, fSuppress)
}
cpu.assert(false);
if (!fSuppress) X86Help.opHelpFault.call(cpu, X86.EXCEPTION.GP_FAULT, sel, true);
base = null;
base = X86.ADDR_INVALID;
break;
}
else if (type == X86.DESC.ACC.TYPE.GATE_INT || type == X86.DESC.ACC.TYPE.GATE_TRAP) {
selCode = base & 0xffff;
if (dpl > this.cpl) {
accCode = this.loadAcc(selCode, true);
if (accCode != null && (accCode & X86.DESC.ACC.TYPE.CODE_CONFORMING) == X86.DESC.ACC.TYPE.CODE_CONFORMING) {
if (accCode != X86.DESC.ACC.INVALID && (accCode & X86.DESC.ACC.TYPE.CODE_CONFORMING) == X86.DESC.ACC.TYPE.CODE_CONFORMING) {
dpl = this.cpl;
}
}
if (dpl <= this.cpl) {
cplPrev = this.cpl;
if (this.load(selCode, true) == null) {
if (this.load(selCode, true) == X86.ADDR_INVALID) {
cpu.assert(false);
base = null;
base = X86.ADDR_INVALID;
break;
}
cpu.regIP = limit;
if (this.cpl < cplPrev) {
if (fCall !== true) {
base = null;
base = X86.ADDR_INVALID;
break;
}
regSP = cpu.regSP;
@ -657,22 +672,22 @@ X86Seg.prototype.loadDesc8 = function(addrDesc, sel, fSuppress)
}
cpu.assert(false);
if (!fSuppress) X86Help.opHelpFault.call(cpu, X86.EXCEPTION.GP_FAULT, sel | X86.ERRCODE.EXT, true);
base = null;
base = X86.ADDR_INVALID;
break;
}
else if (type == X86.DESC.ACC.TYPE.GATE_TASK) {
if (!X86Seg.switchTSS.call(this, base & 0xffff, true)) {
base = null;
base = X86.ADDR_INVALID;
break;
}
return this.base;
}
else {
if (!fSuppress) X86Help.opHelpFault.call(cpu, X86.EXCEPTION.GP_FAULT, sel, true);
base = null;
base = X86.ADDR_INVALID;
break;
}
cpu.assert(!!selMasked); // a null CS selector should be caught by the final preceding check
cpu.assert(!!selMasked); // a zero CS selector should be caught by the final preceding check
}
else if (this.id == X86Seg.ID.DATA) {
if (selMasked) {
@ -700,7 +715,7 @@ X86Seg.prototype.loadDesc8 = function(addrDesc, sel, fSuppress)
* So, if acc is zero, we won't set fHalt on the following call.
*/
if (!fSuppress) X86Help.opHelpFault.call(cpu, X86.EXCEPTION.GP_FAULT, sel, acc != 0);
base = null;
base = X86.ADDR_INVALID;
break;
}
}
@ -708,14 +723,14 @@ X86Seg.prototype.loadDesc8 = function(addrDesc, sel, fSuppress)
else if (this.id == X86Seg.ID.STACK) {
if (!selMasked || type < X86.DESC.ACC.TYPE.DATA_READONLY || (type & (X86.DESC.ACC.TYPE.CODE | X86.DESC.ACC.TYPE.READABLE)) == X86.DESC.ACC.TYPE.CODE) {
if (!fSuppress) X86Help.opHelpFault.call(cpu, X86.EXCEPTION.GP_FAULT, sel, true);
base = null;
base = X86.ADDR_INVALID;
break;
}
}
else if (this.id == X86Seg.ID.TSS) {
if (!selMasked || type != X86.DESC.ACC.TYPE.TSS && type != X86.DESC.ACC.TYPE.TSS_BUSY) {
if (!fSuppress) X86Help.opHelpFault.call(cpu, X86.EXCEPTION.TS_FAULT, sel, true);
base = null;
base = X86.ADDR_INVALID;
break;
}
}
@ -724,7 +739,7 @@ X86Seg.prototype.loadDesc8 = function(addrDesc, sel, fSuppress)
* For LSL, we must support any descriptor marked X86.DESC.ACC.TYPE.SEG, as well as TSS and LDT descriptors.
*/
if (!(acc & X86.DESC.ACC.TYPE.SEG) && type > X86.DESC.ACC.TYPE.TSS_BUSY) {
base = null;
base = X86.ADDR_INVALID;
break;
}
}
@ -737,7 +752,7 @@ X86Seg.prototype.loadDesc8 = function(addrDesc, sel, fSuppress)
this.updateMode();
break;
}
if (!fSuppress) this.messageDebugger(sel, base, limit, acc, ext);
if (!fSuppress) this.messageSeg(sel, base, limit, acc, ext);
return base;
};
@ -847,21 +862,22 @@ X86Seg.prototype.updateMode = function(fProt)
this.checkWrite = X86Seg.checkWriteReal;
this.limit = 0xffff;
this.cpl = this.dpl = 0;
this.addrDesc = null;
this.addrDesc = X86.ADDR_INVALID;
}
return fProt;
};
/**
* messageDebugger(sel base, limit, acc, ext)
* messageSeg(sel, base, limit, acc, ext)
*
* @this {X86Seg}
* @param {number} sel
* @param {number|null} base
* @param {number} base
* @param {number} limit
* @param {number} acc
* @param {number} [ext]
*/
X86Seg.prototype.messageDebugger = function(sel, base, limit, acc, ext)
X86Seg.prototype.messageSeg = function(sel, base, limit, acc, ext)
{
if (DEBUG) {
if (DEBUGGER && this.dbg && this.dbg.messageEnabled(Debugger.MESSAGE.SEG)) {
@ -870,7 +886,7 @@ X86Seg.prototype.messageDebugger = function(sel, base, limit, acc, ext)
if (this.id == X86Seg.ID.CODE) sDPL += " cpl=" + this.cpl;
this.dbg.message("loadSeg(" + this.sName + "):" + ch + "sel=" + str.toHexWord(sel) + " base=" + str.toHex(base) + " limit=" + str.toHexWord(limit) + " acc=" + str.toHexWord(acc) + sDPL);
}
this.cpu.assert(/* base != null && */ (!ext || ext == X86.DESC.EXT.AVAIL));
this.cpu.assert(/* base != X86.ADDR_INVALID && */ (!ext || ext == X86.DESC.EXT.AVAIL));
}
};