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More protected-mode improvements

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This commit is contained in:
Jeff Parsons 2014-11-25 17:21:20 -08:00 • committed by jeffpar
commit 9523de773d
7 changed files with 197 additions and 115 deletions
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239
modules/pcjs/lib/x86seg.js
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@ -60,7 +60,7 @@ function X86Seg(cpu, id, sName, fProt)
this.cpl = 0;
this.dpl = 0;
this.awScratch = (this.id == X86Seg.ID.CODE? new Array(32) : []);
this.updateAccess(fProt || false);
this.updateAccess(fProt);
}
X86Seg.ID = {
@ -138,6 +138,9 @@ X86Seg.loadProt = function loadProt(sel, fSuppress)
if (!fSuppress) this.cpu.nStepCycles -= 15;
return this.loadDesc8(sel, addrDesc);
}
if (!fSuppress) {
X86Help.opHelpFault.call(this.cpu, X86.EXCEPTION.GP_FAULT, sel);
}
return null;
};
@ -176,7 +179,7 @@ X86Seg.checkWriteReal = function checkWriteReal(off, cb, fSuppress)
};
/**
* checkReadProtEnabled(off, cb, fSuppress)
* checkReadProt(off, cb, fSuppress)
*
* @this {X86Seg}
* @param {number} off is a segment-relative offset
@ -184,16 +187,16 @@ X86Seg.checkWriteReal = function checkWriteReal(off, cb, fSuppress)
* @param {boolean} [fSuppress] is true to suppress any errors
* @return {number|null} corresponding physical address if valid, null if not
*/
X86Seg.checkReadProtEnabled = function checkReadProtEnabled(off, cb, fSuppress)
X86Seg.checkReadProt = function checkReadProt(off, cb, fSuppress)
{
if (off + cb <= this.limit) {
return this.base + off;
}
return X86Seg.checkReadProtDisabled.call(this, off, cb, fSuppress);
return X86Seg.checkReadProtDisallowed.call(this, off, cb, fSuppress);
};
/**
* checkReadProtDisabled(off, cb, fSuppress)
* checkReadProtDown(off, cb, fSuppress)
*
* @this {X86Seg}
* @param {number} off is a segment-relative offset
@ -201,7 +204,24 @@ X86Seg.checkReadProtEnabled = function checkReadProtEnabled(off, cb, fSuppress)
* @param {boolean} [fSuppress] is true to suppress any errors
* @return {number|null} corresponding physical address if valid, null if not
*/
X86Seg.checkReadProtDisabled = function checkReadProtDisabled(off, cb, fSuppress)
X86Seg.checkReadProtDown = function checkReadProtDown(off, cb, fSuppress)
{
if (off + cb > this.limit) {
return this.base + off;
}
return X86Seg.checkReadProtDisallowed.call(this, off, cb, fSuppress);
};
/**
* checkReadProtDisallowed(off, cb, fSuppress)
*
* @this {X86Seg}
* @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
*/
X86Seg.checkReadProtDisallowed = function checkReadProtDisallowed(off, cb, fSuppress)
{
if (!fSuppress) {
X86Help.opHelpFault.call(this.cpu, X86.EXCEPTION.GP_FAULT, 0);
@ -210,7 +230,7 @@ X86Seg.checkReadProtDisabled = function checkReadProtDisabled(off, cb, fSuppress
};
/**
* checkWriteProtEnabled(off, cb, fSuppress)
* checkWriteProt(off, cb, fSuppress)
*
* @this {X86Seg}
* @param {number} off is a segment-relative offset
@ -218,16 +238,16 @@ X86Seg.checkReadProtDisabled = function checkReadProtDisabled(off, cb, fSuppress
* @param {boolean} [fSuppress] is true to suppress any errors
* @return {number|null} corresponding physical address if valid, null if not
*/
X86Seg.checkWriteProtEnabled = function checkWriteProtEnabled(off, cb, fSuppress)
X86Seg.checkWriteProt = function checkWriteProt(off, cb, fSuppress)
{
if (off + cb <= this.limit) {
return this.base + off;
}
return X86Seg.checkWriteProtDisabled.call(this, off, cb, fSuppress);
return X86Seg.checkWriteProtDisallowed.call(this, off, cb, fSuppress);
};
/**
* checkWriteProtDisabled(off, cb, fSuppress)
* checkWriteProtDown(off, cb, fSuppress)
*
* @this {X86Seg}
* @param {number} off is a segment-relative offset
@ -235,7 +255,24 @@ X86Seg.checkWriteProtEnabled = function checkWriteProtEnabled(off, cb, fSuppress
* @param {boolean} [fSuppress] is true to suppress any errors
* @return {number|null} corresponding physical address if valid, null if not
*/
X86Seg.checkWriteProtDisabled = function checkWriteProtDisabled(off, cb, fSuppress)
X86Seg.checkWriteProtDown = function checkWriteProtDown(off, cb, fSuppress)
{
if (off + cb > this.limit) {
return this.base + off;
}
return X86Seg.checkWriteProtDisallowed.call(this, off, cb, fSuppress);
};
/**
* checkWriteProtDisallowed(off, cb, fSuppress)
*
* @this {X86Seg}
* @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
*/
X86Seg.checkWriteProtDisallowed = function checkWriteProtDisallowed(off, cb, fSuppress)
{
if (!fSuppress) {
X86Help.opHelpFault.call(this.cpu, X86.EXCEPTION.GP_FAULT, 0);
@ -250,7 +287,7 @@ X86Seg.checkWriteProtDisabled = function checkWriteProtDisabled(off, cb, fSuppre
/**
* loadDesc6(sel, addrDesc)
*
* Used to load a protected-mode selector that refers to a 6-byte descriptor "cache" (LOADALL) entry:
* Used to load a protected-mode selector that refers to a 6-byte "descriptor cache" (aka LOADALL) entry:
*
* word 0: base address low
* word 1: base address high (0-7), segment type (8-11), descriptor type (12), DPL (13-14), present bit (15)
@ -282,7 +319,7 @@ X86Seg.prototype.loadDesc6 = function(sel, addrDesc)
/**
* loadDesc8(sel, addrDesc)
*
* Used to load a protected-mode selector that refers to an 8-byte descriptor table (GDT, LDT, IDT) entry:
* Used to load a protected-mode selector that refers to an 8-byte "descriptor table" (GDT, LDT, IDT) entry:
*
* word 0: segment limit (0-15)
* word 1: base address low
@ -303,93 +340,101 @@ X86Seg.prototype.loadDesc8 = function(sel, addrDesc)
var type = (acc & X86.DESC.ACC.TYPE.MASK);
var base = this.cpu.getWord(addrDesc + X86.DESC.BASE.OFFSET) | ((acc & X86.DESC.ACC.BASE1623) << 16);
var ext = (DEBUG? this.cpu.getWord(addrDesc + X86.DESC.EXT.OFFSET) : 0);
var selMasked = sel & X86.SEL.MASK;
while (true) {
if (sel) {
/*
* TODO: These descriptor tests are far from complete....
*/
if (this.id == X86Seg.ID.CODE) {
this.fReturn = false;
var rpl = sel & X86.SEL.RPL;
var dpl = (acc & X86.DESC.ACC.DPL.MASK) >> X86.DESC.ACC.DPL.SHIFT;
var regSP;
if (type == X86.DESC.ACC.TYPE.GATE_CALL) {
/*
* Since we are X86Seg.ID.CODE, we can use this.cpl instead of the more generic this.cpu.segCS.cpl
*/
if (rpl < this.cpl) rpl = this.cpl;
if (rpl <= dpl) {
var cplPrev = this.cpl;
if (this.load(base & 0xffff, true) != null) {
this.cpu.regIP = limit;
if (this.cpl < cplPrev) {
if (this.fCall !== true) {
base = null;
break;
}
regSP = this.cpu.regSP;
var i = 0, nWords = (acc & 0x1f);
while (nWords--) {
this.awScratch[i++] = this.cpu.getSOWord(this.cpu.segSS, regSP);
regSP += 2;
}
var addrTSS = this.cpu.segTSS.base;
var offSP = (this.cpl << 2) + X86.TSS.CPL0_SP;
var offSS = offSP + 2;
var regSPPrev = this.cpu.regSP;
var regSSPrev = this.cpu.segSS.sel;
this.cpu.regSP = this.cpu.getWord(addrTSS + offSP);
this.cpu.segSS.load(this.cpu.getWord(addrTSS + offSS));
this.cpu.pushWord(regSSPrev);
this.cpu.pushWord(regSPPrev);
while (i) this.cpu.pushWord(this.awScratch[--i]);
if (this.id == X86Seg.ID.CODE) {
this.fStackSwitch = false;
var fCall = this.fCall;
var rpl = sel & X86.SEL.RPL;
var dpl = (acc & X86.DESC.ACC.DPL.MASK) >> X86.DESC.ACC.DPL.SHIFT;
var regSP;
if (type == X86.DESC.ACC.TYPE.GATE_CALL) {
/*
* Since we are X86Seg.ID.CODE, we can use this.cpl instead of the more generic this.cpu.segCS.cpl
*/
if (rpl < this.cpl) rpl = this.cpl;
if (rpl <= dpl) {
var cplPrev = this.cpl;
if (this.load(base & 0xffff, true) != null) {
this.cpu.regIP = limit;
if (this.cpl < cplPrev) {
if (fCall !== true) {
base = null;
break;
}
return this.base;
regSP = this.cpu.regSP;
var i = 0, nWords = (acc & 0x1f);
while (nWords--) {
this.awScratch[i++] = this.cpu.getSOWord(this.cpu.segSS, regSP);
regSP += 2;
}
var addrTSS = this.cpu.segTSS.base;
var offSP = (this.cpl << 2) + X86.TSS.CPL0_SP;
var offSS = offSP + 2;
var regSPPrev = this.cpu.regSP;
var regSSPrev = this.cpu.segSS.sel;
this.cpu.regSP = this.cpu.getWord(addrTSS + offSP);
this.cpu.segSS.load(this.cpu.getWord(addrTSS + offSS));
this.cpu.pushWord(regSSPrev);
this.cpu.pushWord(regSPPrev);
while (i) this.cpu.pushWord(this.awScratch[--i]);
this.fStackSwitch = true;
}
return this.base;
}
}
else if (type >= X86.DESC.ACC.TYPE.CODE_EXECONLY /* || dpl > this.cpu.segCS.cpl */) {
rpl = sel & X86.SEL.RPL;
if (rpl > this.cpl) {
if (this.fCall !== false) {
base = null;
break;
}
regSP = this.cpu.popWord();
this.cpu.segSS.load(this.cpu.popWord());
this.cpu.regSP = regSP;
this.fReturn = true;
}
}
else {
X86Help.opHelpFault.call(this.cpu, X86.EXCEPTION.GP_FAULT, sel, true);
base = null;
break;
}
}
else if (this.id == X86Seg.ID.DATA || this.id == X86Seg.ID.STACK) {
else if (type >= X86.DESC.ACC.TYPE.CODE_EXECONLY /* || dpl > this.cpu.segCS.cpl */) {
rpl = sel & X86.SEL.RPL;
if (rpl > this.cpl) {
if (fCall !== false) {
base = null;
break;
}
regSP = this.cpu.popWord();
this.cpu.segSS.load(this.cpu.popWord());
this.cpu.regSP = regSP;
this.fStackSwitch = true;
}
}
else {
X86Help.opHelpFault.call(this.cpu, X86.EXCEPTION.GP_FAULT, sel, true);
base = null;
break;
}
if (DEBUG) this.cpu.assert(!!selMasked); // a null CS selector should be caught by the final preceding check
}
else if (this.id == X86Seg.ID.DATA) {
if (selMasked) {
if (type < X86.DESC.ACC.TYPE.DATA_READONLY || (type & (X86.DESC.ACC.TYPE.CODE | X86.DESC.ACC.TYPE.READABLE)) == X86.DESC.ACC.TYPE.CODE) {
X86Help.opHelpFault.call(this.cpu, X86.EXCEPTION.GP_FAULT, sel, true);
base = null;
break;
}
}
else if (this.id == X86Seg.ID.TSS) {
if (type != X86.DESC.ACC.TYPE.TSS && type != X86.DESC.ACC.TYPE.TSS_BUSY) {
X86Help.opHelpFault.call(this.cpu, X86.EXCEPTION.TS_FAULT, sel, true);
base = null;
break;
}
}
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) {
X86Help.opHelpFault.call(this.cpu, X86.EXCEPTION.GP_FAULT, sel, true);
base = null;
break;
}
else if (this.id == X86Seg.ID.OTHER) {
/*
* 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;
break;
}
}
else if (this.id == X86Seg.ID.TSS) {
if (!selMasked || type != X86.DESC.ACC.TYPE.TSS && type != X86.DESC.ACC.TYPE.TSS_BUSY) {
X86Help.opHelpFault.call(this.cpu, X86.EXCEPTION.TS_FAULT, sel, true);
base = null;
break;
}
}
else if (this.id == X86Seg.ID.OTHER) {
/*
* 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;
break;
}
}
this.sel = sel;
@ -473,28 +518,32 @@ X86Seg.prototype.restore = function(a)
*/
X86Seg.prototype.updateAccess = function(fProt)
{
if (fProt !== undefined) {
this.fCall = null; // true if "CALLF" in progress, false if "RETF [n]" in progress, null/undefined otherwise (X86Seg.ID.CODE only)
this.fReturn = false; // true if "RETF" performed, false otherwise
} else {
if (fProt === undefined) {
fProt = !!(this.cpu.regMSW & X86.MSW.PE);
}
if (fProt) {
this.load = X86Seg.loadProt;
this.checkRead = X86Seg.checkReadProtEnabled;
this.checkWrite = X86Seg.checkWriteProtEnabled;
this.checkRead = X86Seg.checkReadProt;
this.checkWrite = X86Seg.checkWriteProt;
if (this.acc & X86.DESC.ACC.TYPE.SEG) {
/*
* If the READABLE bit of CODE_READABLE is not set, then disallow reads
*/
if ((this.acc & X86.DESC.ACC.TYPE.CODE_READABLE) == X86.DESC.ACC.TYPE.CODE_EXECONLY) {
this.checkWrite = X86Seg.checkReadProtDisabled;
this.checkWrite = X86Seg.checkReadProtDisallowed;
}
/*
* If the CODE bit is set, or the the WRITABLE bit is not set, then disallow writes
*/
if ((this.acc & X86.DESC.ACC.TYPE.CODE) || !(this.acc & X86.DESC.ACC.TYPE.WRITABLE)) {
this.checkWrite = X86Seg.checkWriteProtDisabled;
this.checkWrite = X86Seg.checkWriteProtDisallowed;
}
/*
* If the CODE bit is not set *and* the EXPDOWN bit is set, then invert the limit check
*/
if ((this.acc & (X86.DESC.ACC.TYPE.CODE | X86.DESC.ACC.TYPE.EXPDOWN)) == X86.DESC.ACC.TYPE.EXPDOWN) {
if (this.checkRead == X86Seg.checkReadProt) this.checkRead = X86Seg.checkReadProtDown;
if (this.checkWrite == X86Seg.checkWriteProt) this.checkWrite = X86Seg.checkWriteProtDown;
}
}
this.cpl = this.sel & X86.SEL.RPL;
@ -506,6 +555,8 @@ X86Seg.prototype.updateAccess = function(fProt)
this.cpl = this.dpl = 0;
this.addrDesc = null;
}
this.fCall = null; // true if CALLF in progress, false if RETF in progress, null/undefined otherwise (X86Seg.ID.CODE only)
this.fStackSwitch = false; // true if a stack switch occurred on the last loadDesc8(), false otherwise (X86Seg.ID.CODE only)
return fProt;
};